Ionizing radiation: its biological impacts and how it is used to treat disease

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Hello, and welcome to the Physics World weekly

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podcast.

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Our guests this week are two medical physicists

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who talk about the biological

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impacts of ionizing

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radiation.

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And they also explain how radiation can be

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used to treat diseases

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such as cancer.

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This episode was created in collaboration

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with IPEM,

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the Institute of Physics and Engineering in Medicine.

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IPEM owns the journal Physics in Medicine and

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Biology.

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Here's Physics World's Tammy Freeman in conversation

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with our two guests.

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Radiation is both a hazard to the human

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body and a beneficial tool that can be

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exploited for medical application.

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Radiation therapy, for example, uses beams of photons

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or charged particles such as protons to destroy

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tumors.

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But how exactly does the radiation kill cancer

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cells?

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How can we prevent normal tissue from getting

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damaged during this process?

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And how are medical physicists

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exploiting the underlying

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radio biology processes for the benefit of patients?

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To discuss these questions in more depth, I'm

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joined today by Ileana Silvestre

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Palacio,

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medical physicist working at The UK's National Physical

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Laboratory,

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and Ruth McLaughlin,

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consultant radiotherapy

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physicist

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at Imperial College Healthcare NHS Trust.

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Welcome to the podcast, Ruth and Ileana.

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Thank you.

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Hello. Thank you.

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So let's start by looking at radio therapy.

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This is used to treat cancers, and this

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is a really important medical use of radiation.

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So can you just briefly explain how this

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treatment works?

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We're using radiation, usually high energy x X

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rays, but there's other modalities like electrons and

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protons and carbon ions, basically to kill the

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cancer cells so that we can shrink and

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destroy the tumor.

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We're aiming to cause the maximum damage to

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the tumor

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while minimizing

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the radiation effects of the normal and the

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healthy tissues.

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The radiation damages the DNA of the cancer

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cells causing them to stop dividing and to

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die.

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The cancer cells will continue to,

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die for weeks or even months following the

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radiotherapy treatment,

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but it can also affect the healthy cells

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causing temporary cell damage.

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Most healthy cells, though, will recover,

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and they'll go back to working normally, and

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the side effects

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usually improve a few weeks following completion of

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treatment.

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Okay. So how are the the beams of

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ionizing radiation are directed onto the tumour? So

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how how do they actually kill the cancer

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cells?

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Before commenting on how ionizing radiation

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kill cancer cells,

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I could be it could be worth talking

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about radiobiology

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in relation to the radiotherapy process.

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Radiobiology

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is a multidisciplinary

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area of science

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that involves all aspects

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of biology,

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physics, and medicine,

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and and to study how radiation affects cells,

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the tissues, and biological systems as well. It

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is is

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a specialty that intends to understand

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how radiation induce damages,

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the repair mechanisms,

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and the biological response to radiation.

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So what happens then when cells are exposed

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to ionization

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ionizing radiation?

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At first, there is a physical

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effect between the radiation and the atoms of

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molecules

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on that occurs into those cells. But as

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a consequence of that, then a possible biological

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damage to the cell functions will follow, and

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that damage will end up in killing and

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really,

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causing the death of the cells,

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which can could occur through a process of

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apoptosis,

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necrosis,

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or mitosis of

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the cells.

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That more or less, that's what I think

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how what happened. Yes.

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How do we know that cells react to

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radiation?

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Through studying the effects on people who have

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been subject to to radiation.

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And a lot of the information we've got,

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unfortunately, has been the result of radiation incidents

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and accidents, the atomic bombs,

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the Chernobyl incidents, for example.

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But also

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for many, many, many years, patients have received

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radiation as part of their cancer treatment.

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So we have large cancer registries,

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so we can follow-up these patients or the

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people who've been involved in these incidents

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and,

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look at

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how their exposure to radiation,

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is there any link to that, to any

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side effects that we see in them in

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in later life. And then scientists try to

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apply models

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to that,

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try to relate the level of exposure, the

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type of exposure with the effects that they

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see, and see if they can use that

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to predict

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how for future

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patients

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or people

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coming into contact with radiation

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predict how they are likely to be affected

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by that dose.

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Okay. So

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when you're delivering radiation therapy,

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treatments are usually delivered using a series of

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daily radiation, so a treatment every day over

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several weeks.

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And this is called fractionation.

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So can you explain why this is used

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and what are the benefits of this?

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Oh, yeah. I could say a little bit

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even going a little bit back, you know,

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at the beginning of the twentieth century where

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where some doctors were already using radiation

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to treat certain

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tumors.

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As an interesting fact, that was the case

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of the Scottish radiotherapist,

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Ralston Patterson,

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who who used x rays to treat patients

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with primary carcinomas of the lung.

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At this early period,

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the pioneers of radiotherapy did not really know

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what was the dose

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fractionated

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dose of x rays.

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So the concept of fractionation of the x-ray

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treatment was introduced by Claude

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of the x-ray treatment was introduced by Claudius

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Rigault

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from the Foundation

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Curie in Paris and his collaborator,

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Henrik Couture.

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It was introduced at the first International Congress

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of Radiology,

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which was held in 1925 in London.

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So Regard

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irradiated, previous to the conference, of course, and

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through their investigation,

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irradiated testicular tissues of in grams and observed

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that different types of of cell had different

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sensitive to radiation.

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And with that result, it was then increasingly

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appreciated that cells in a state of growth,

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division, and reproduction

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were more radiosensitive

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than those in resting states

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stages,

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and then that began to influence

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treatment decisions in terms of the overall dose

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and how often or how frequent this dose

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will will be delivered.

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And that is the hypothesis

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on in vitro study was then translated

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to clinical study to the first clinical study

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by Couture

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who introduced protracted

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fractionation radiotherapy

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in human patients

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so early

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as in talking about the beginnings of the

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twentieth century.

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The the first findings became the cornerstone of

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the conventional radiotherapy fractionation

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as they are used up to today.

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And that led to also to the understanding

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of the principle of the functioning of the

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four heirs in radiotherapy.

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It means the

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function of the repair, redistribution,

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repopulation,

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and oxygenation,

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as well as of the understanding of the

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linear quadratic model, which is the model that

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is mostly used

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for understanding what to be the fractionation.

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So you mentioned that cells at different stages

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in their cycle react differently to radiation.

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Do different types of cells themselves also react

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differently to radiation?

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They do. Not all cells are equally sensitive

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to radiation. Elian has already said about radiation

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sensitivity,

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and the linear quadratic model,

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and parameters on that are give us our

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alpha beta ratio, and the values of that

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is related to how radio sensitive cells are.

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Generally, it's cells that are actively dividing and

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replicating that are more vulnerable

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because the radiation damage to their DNA can

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disrupt the cell cycle and lead to cell

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death and mutations.

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So lymphocytes, white blood cells, blood forming cells

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like in the bone marrow are highly sensitive

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due to their rapid turnover and constant regeneration.

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Reproductive and gastrointestinal

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cells also fall into this category.

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Nerve and muscle cells are relatively resistant to

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radiation damage because they divide infrequently.

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And with radiotherapy treatments, we see different effects

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at different time points

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even during and certainly post radiotherapy treatment.

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Acute early effects,

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we can often see them starting actually during

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treatment because we we're treating patients

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daily over a number of weeks, and these

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effects can actually occur while we're still delivering

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the treatment. It depends on where in the

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body exactly we're treating, but fatigue is a

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common side effect,

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skin reactions,

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hair loss in the treatment area, if we're

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treating the head and neck region,

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dry mouth, if we're treating the pelvic region,

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bladder irritation can cause frequent need to go

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to the toilet.

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But medications can be given to counter a

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lot of these things, and improvements usually seem

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within six to eight weeks

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following the completion of the rate of the

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treatment.

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But late effects,

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they can occur months or even years

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after the radiotherapy treatment. And we're when we're

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designing

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our radiotherapy treatments, we're very aware

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of potentials of these late effects and minimizing

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the chances of these things happening. And things

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that you can see years later can be

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fibrosis of the skin,

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cognitive changes to the brain if we've irradiated

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the brain,

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cataracts,

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and heart complications.

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Okay. So it's it's obviously, like, really important

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to make sure that it's a little as

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possible radiation to normal tissue.

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So

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we we can use physics techniques to protect

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normal tissues by precisely shaping

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and directing the radiation

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beams during the treatment.

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Can you can you explain how this works?

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The use of highly conforming radiation techniques

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00:10:57,264 --> 00:10:59,825
reduce the area of healthy healthy tissue that

286
00:10:59,825 --> 00:11:01,044
can be that

287
00:11:01,504 --> 00:11:02,245
is irradiated.

288
00:11:02,945 --> 00:11:05,745
That can be in the in the these

289
00:11:05,745 --> 00:11:08,404
days is supported by the use of some

290
00:11:08,759 --> 00:11:10,540
devices called multi leaf collimators,

291
00:11:10,920 --> 00:11:12,840
but also with the use of micro leaf

292
00:11:12,840 --> 00:11:14,300
collimator, which are even

293
00:11:14,679 --> 00:11:17,259
devices that have thinner leaves that conform

294
00:11:17,879 --> 00:11:20,759
the shape to the treatment volume and spare

295
00:11:20,759 --> 00:11:23,179
the healthy tissue as most as possible.

296
00:11:23,485 --> 00:11:26,365
But also with the implementation of so called

297
00:11:26,365 --> 00:11:26,865
stereotactic

298
00:11:27,404 --> 00:11:31,245
kind of therapeutic deliveries, which try to treat

299
00:11:31,245 --> 00:11:32,144
very small

300
00:11:32,605 --> 00:11:35,965
volumes, but also with very small collimators, could

301
00:11:35,965 --> 00:11:39,590
be circular collimator or also conformed by different

302
00:11:39,590 --> 00:11:41,690
leaves. That's one way of

303
00:11:42,149 --> 00:11:43,049
supporting the

304
00:11:43,509 --> 00:11:46,230
improvement of treating the tumor and not treating

305
00:11:46,230 --> 00:11:47,910
the or not giving those to the health

306
00:11:47,910 --> 00:11:48,410
tissue.

307
00:11:48,804 --> 00:11:51,125
But also lately, we there is a path

308
00:11:51,205 --> 00:11:53,384
pipeline to for the introduction of,

309
00:11:55,764 --> 00:11:56,665
adaptive radiotherapy.

310
00:11:57,205 --> 00:11:59,605
So maybe I will left Ruth to speak

311
00:11:59,605 --> 00:12:02,165
a little bit how that adaptive radiotherapy can

312
00:12:02,165 --> 00:12:05,240
help to improve the radiotherapy process in general

313
00:12:05,240 --> 00:12:07,879
and the protection of the healthy tissues while

314
00:12:07,879 --> 00:12:09,419
giving the dose to the tumor?

315
00:12:10,279 --> 00:12:12,360
So I I've been working as a clinical

316
00:12:12,360 --> 00:12:15,000
radiotherapy physicist for over twenty years now. And

317
00:12:15,000 --> 00:12:17,514
in that twenty years, we've seen massive advances

318
00:12:17,575 --> 00:12:20,055
in the technology and way that we can

319
00:12:20,055 --> 00:12:20,955
better target

320
00:12:21,335 --> 00:12:22,235
those high doses,

321
00:12:22,695 --> 00:12:23,915
to the tumors. So

322
00:12:24,375 --> 00:12:26,715
we've always treated with multiple beams.

323
00:12:27,415 --> 00:12:29,860
That allows us to build up a high

324
00:12:29,860 --> 00:12:32,839
dose by targeting it at the tumor while

325
00:12:32,980 --> 00:12:33,480
distributing

326
00:12:33,860 --> 00:12:36,500
the a lower dose to the surrounding tissues.

327
00:12:36,500 --> 00:12:38,579
But as Ileana said, one of the big

328
00:12:38,579 --> 00:12:40,759
advances was the use of the multileaf collimator.

329
00:12:41,139 --> 00:12:43,424
Twenty five years ago, the majority of external

330
00:12:43,424 --> 00:12:46,245
beam radiotherapy treatments, we were treating with rectangular

331
00:12:46,384 --> 00:12:48,384
fields. So you can imagine there was quite

332
00:12:48,384 --> 00:12:51,664
a lot of adjacent normal tissues included in

333
00:12:51,664 --> 00:12:53,044
those high dose volumes.

334
00:12:53,345 --> 00:12:56,339
The multi leaf collimators, which are these little

335
00:12:56,399 --> 00:12:59,440
leaves of tungsten that allow us to better

336
00:12:59,440 --> 00:12:59,940
shape,

337
00:13:00,879 --> 00:13:03,279
the radiation field to the shape of the

338
00:13:03,279 --> 00:13:04,100
of the tumor,

339
00:13:04,559 --> 00:13:07,379
allowed us to better protect the normal tissues,

340
00:13:07,519 --> 00:13:09,424
but also paved the way for us to

341
00:13:09,424 --> 00:13:11,764
be able to deliver these treatments more dynamically.

342
00:13:12,065 --> 00:13:14,884
Instead of static beams, we can now

343
00:13:15,904 --> 00:13:18,625
treat where we are with the beam on,

344
00:13:18,625 --> 00:13:21,569
the machine is rotating around the patient, the

345
00:13:21,569 --> 00:13:22,709
multileaf collimators

346
00:13:23,169 --> 00:13:25,730
are moving. We can vary the rate at

347
00:13:25,730 --> 00:13:28,049
which the dose is delivered. With the modern

348
00:13:28,049 --> 00:13:28,549
computational,

349
00:13:31,569 --> 00:13:33,669
software and power that we've got,

350
00:13:34,209 --> 00:13:35,029
we can now

351
00:13:35,455 --> 00:13:37,855
tell the computer what we want the dose

352
00:13:37,855 --> 00:13:40,095
distribution to look like, and it can run

353
00:13:40,095 --> 00:13:41,955
its inverse planning algorithms

354
00:13:42,575 --> 00:13:43,235
to calculate

355
00:13:43,774 --> 00:13:46,495
how better that could be delivered. And it's

356
00:13:46,495 --> 00:13:48,595
all about targeting that high dose

357
00:13:49,039 --> 00:13:51,360
to to the tumor. And the advent of

358
00:13:51,360 --> 00:13:54,079
image guidance as well, now we can image

359
00:13:54,079 --> 00:13:54,740
the patient

360
00:13:55,439 --> 00:13:56,259
on the machine

361
00:13:57,199 --> 00:13:59,279
as they're in their treatment position just before

362
00:13:59,279 --> 00:14:01,439
we then treat them. We we can delete

363
00:14:01,600 --> 00:14:02,980
we can acquire

364
00:14:03,514 --> 00:14:04,735
home beam CT,

365
00:14:05,355 --> 00:14:08,475
good quality CT image that's showing us how

366
00:14:08,475 --> 00:14:10,815
well the patient's set up, how the anatomy

367
00:14:11,035 --> 00:14:13,595
we can compare that with the planning images

368
00:14:13,595 --> 00:14:14,414
that we took,

369
00:14:14,955 --> 00:14:16,495
to make sure that we are

370
00:14:17,009 --> 00:14:18,470
targeting that treatment

371
00:14:18,850 --> 00:14:21,170
where we intend it to be treated. And

372
00:14:21,170 --> 00:14:23,570
because we're now getting this three d image

373
00:14:23,570 --> 00:14:24,070
information,

374
00:14:24,370 --> 00:14:27,170
we can actually see if the anatomy's changed,

375
00:14:27,170 --> 00:14:29,330
if the tumor has grown, if the tumor

376
00:14:29,330 --> 00:14:31,164
has shrunk, and this is paving the way

377
00:14:31,164 --> 00:14:33,004
for us to be able to adapt treatment

378
00:14:33,004 --> 00:14:35,725
further to respond to how those tumors are

379
00:14:35,725 --> 00:14:37,985
changing while we are treating the patient.

380
00:14:38,524 --> 00:14:40,304
So so this is what's known as adaptive

381
00:14:40,365 --> 00:14:40,865
radiotherapy.

382
00:14:41,404 --> 00:14:43,105
So for example, if,

383
00:14:43,779 --> 00:14:46,659
something's changed in the patient's anatomy between the

384
00:14:46,659 --> 00:14:47,159
treatments,

385
00:14:47,620 --> 00:14:48,919
you can change the delivery

386
00:14:50,179 --> 00:14:52,899
to match the anatomy changes and make sure

387
00:14:52,899 --> 00:14:53,960
it stays accurate.

388
00:14:55,139 --> 00:14:57,480
So you've got these really accurate

389
00:14:57,945 --> 00:14:58,445
plans.

390
00:14:58,904 --> 00:15:01,644
But how how can physicists help prevent

391
00:15:02,504 --> 00:15:03,004
unintentional

392
00:15:03,705 --> 00:15:04,524
over radiation

393
00:15:04,985 --> 00:15:07,065
during treatments? How do they know that everything's

394
00:15:07,065 --> 00:15:09,565
gonna work perfectly before they start?

395
00:15:10,184 --> 00:15:12,205
Every radiotherapy equipment is under

396
00:15:12,825 --> 00:15:14,709
restricted and very well

397
00:15:15,649 --> 00:15:16,870
defined quality

398
00:15:17,250 --> 00:15:18,549
assurance program.

399
00:15:19,169 --> 00:15:21,649
So, not only the machine itself, it has

400
00:15:21,649 --> 00:15:23,589
a daily QA

401
00:15:24,449 --> 00:15:24,929
test,

402
00:15:25,329 --> 00:15:29,334
monthly, yearly, but also the plans are specifically

403
00:15:29,634 --> 00:15:30,615
tested before

404
00:15:31,074 --> 00:15:31,894
giving the

405
00:15:32,274 --> 00:15:34,754
radiotherapy plan to the patient. So there is

406
00:15:34,754 --> 00:15:35,654
something called

407
00:15:36,595 --> 00:15:39,495
a specific patient QA, which is performed

408
00:15:40,019 --> 00:15:43,480
mostly before the first treatment, but perhaps sometimes

409
00:15:43,860 --> 00:15:45,080
in between treatments,

410
00:15:45,700 --> 00:15:46,500
halfway through at the

411
00:15:47,540 --> 00:15:49,860
oh, Ruth maybe have the clinical experience of

412
00:15:49,860 --> 00:15:52,580
what they probably do particularly in her center.

413
00:15:52,580 --> 00:15:55,720
But quality assurance is paramount to keep

414
00:15:56,075 --> 00:15:58,875
safety in the delivery of of radiotherapy treatment

415
00:15:58,875 --> 00:16:00,254
plans, in my opinion.

416
00:16:01,754 --> 00:16:03,914
Everything we do in radiotherapy goes through a

417
00:16:03,914 --> 00:16:06,254
series of checks, and it involves a multidisciplinary

418
00:16:06,715 --> 00:16:09,009
team working together to ensure we provide this

419
00:16:09,009 --> 00:16:11,250
safe and effective treatment for our patients. The

420
00:16:11,250 --> 00:16:13,730
patient's the center of everything we do, and

421
00:16:13,730 --> 00:16:16,710
our team consists of highly trained professionals, including

422
00:16:16,769 --> 00:16:20,210
radiation oncologists, medical physicists, therapeutic radiographers, and other

423
00:16:20,210 --> 00:16:20,710
professionals,

424
00:16:21,254 --> 00:16:23,514
each with specific expertise and responsibilities.

425
00:16:24,375 --> 00:16:26,774
As physicists, we're involved in all aspects of

426
00:16:26,774 --> 00:16:28,154
the radiotherapy pathway.

427
00:16:28,695 --> 00:16:31,654
From creating the accurate treatment plans, implementing the

428
00:16:31,654 --> 00:16:34,235
rigorous quality assurance process procedures,

429
00:16:34,789 --> 00:16:37,509
meticulously calibrating our equipment, making sure that our

430
00:16:37,509 --> 00:16:40,629
equipment is calibrated with a traceable calibration factor

431
00:16:40,629 --> 00:16:43,269
back to Ileana's work at the NPL with

432
00:16:43,269 --> 00:16:44,490
their primary standards,

433
00:16:45,110 --> 00:16:47,429
monitoring the performance of the equipment with a

434
00:16:47,429 --> 00:16:49,995
quality assurance program to ensure that we have

435
00:16:49,995 --> 00:16:52,634
these precise and safe radiation delivery. And, of

436
00:16:52,634 --> 00:16:54,174
course, we're working under legislation,

437
00:16:54,794 --> 00:16:58,495
the, IRR 17, the ionizing radiation regulations,

438
00:16:59,274 --> 00:17:01,214
and Irma, the ionizing radiation

439
00:17:01,670 --> 00:17:03,450
for medical exposure regulations.

440
00:17:04,549 --> 00:17:06,309
Actually, if there is something I can add

441
00:17:06,309 --> 00:17:07,690
to it, it's also interesting.

442
00:17:08,070 --> 00:17:10,470
Something that NPL is quite involved is the

443
00:17:10,470 --> 00:17:14,070
development of, audits or specific audits or end

444
00:17:14,070 --> 00:17:16,775
to end type of audits that actually are

445
00:17:16,775 --> 00:17:19,174
a requirement for hospitals to be able to

446
00:17:19,174 --> 00:17:21,894
participate in clinical trials. So at the moment

447
00:17:21,894 --> 00:17:23,434
at NPL, we are delivering

448
00:17:23,894 --> 00:17:26,555
a a stereotactic radiosurgery end to end audit,

449
00:17:26,694 --> 00:17:28,934
and we are delivering the Spain the Spine

450
00:17:28,934 --> 00:17:31,789
Saver audit, which are two type of audits

451
00:17:31,789 --> 00:17:32,289
that,

452
00:17:33,230 --> 00:17:36,269
verify the whole process since the acquisition of

453
00:17:36,269 --> 00:17:37,730
the CT scan of the patient,

454
00:17:38,109 --> 00:17:40,049
the planning process of the

455
00:17:40,670 --> 00:17:42,914
volumes, and by keeping all the

456
00:17:43,394 --> 00:17:45,475
constraint of the dose to the tumor, dose

457
00:17:45,475 --> 00:17:47,575
to the healthy tissue up to the delivery

458
00:17:47,715 --> 00:17:49,795
of the treatment. So for that, we use,

459
00:17:50,115 --> 00:17:50,615
detectors,

460
00:17:50,914 --> 00:17:51,414
anthropomorphic

461
00:17:51,795 --> 00:17:53,734
functions, so functions that simulate

462
00:17:54,275 --> 00:17:55,795
the part of the body of the patient

463
00:17:55,795 --> 00:17:57,234
that is going to be treated in the

464
00:17:57,234 --> 00:17:58,295
case of the stereotactic

465
00:17:59,109 --> 00:18:00,169
brain surgery,

466
00:18:01,750 --> 00:18:03,269
the area of the head and the neck

467
00:18:03,269 --> 00:18:05,109
of the patient. And in the case of

468
00:18:05,109 --> 00:18:07,769
the savior spine outdid pelvis phantom,

469
00:18:08,230 --> 00:18:10,490
and we deliver that to the hospitals.

470
00:18:10,869 --> 00:18:11,690
They perform

471
00:18:12,335 --> 00:18:15,214
the procedure of delivery or of going through

472
00:18:15,214 --> 00:18:16,815
all the process, and then they send the

473
00:18:16,815 --> 00:18:19,055
fountain back to us where we analyze the

474
00:18:19,055 --> 00:18:21,535
result of the detectors that are inside of

475
00:18:21,535 --> 00:18:22,355
the fountains.

476
00:18:22,815 --> 00:18:25,234
In this case, alanine detectors and film,

477
00:18:26,000 --> 00:18:28,960
graphene detectors. And then we report back to

478
00:18:28,960 --> 00:18:29,460
RTTQA,

479
00:18:29,920 --> 00:18:32,340
which is the organization in The UK that

480
00:18:32,480 --> 00:18:33,460
has the responsibility

481
00:18:33,840 --> 00:18:34,980
to guide and control

482
00:18:35,360 --> 00:18:37,600
all these clinical trials. So that that's an

483
00:18:37,600 --> 00:18:40,799
important asset also also of guaranteeing the safety

484
00:18:40,799 --> 00:18:41,299
and

485
00:18:41,894 --> 00:18:44,335
quality of the plants that are delivered. The

486
00:18:44,455 --> 00:18:45,035
and then

487
00:18:45,414 --> 00:18:47,515
our hospitals are able to compare results

488
00:18:47,815 --> 00:18:50,715
and value of it valuable information can be

489
00:18:50,855 --> 00:18:52,955
obtained from those clinical trials.

490
00:18:53,815 --> 00:18:55,755
And we've just taken part in that. Eliana,

491
00:18:56,375 --> 00:18:59,349
sent us her phantom for our SRS, which

492
00:18:59,349 --> 00:19:00,490
we then scanned,

493
00:19:01,670 --> 00:19:02,170
planned,

494
00:19:02,630 --> 00:19:03,769
delivered the treatment

495
00:19:04,230 --> 00:19:06,309
to that phantom on our treatment machine, and

496
00:19:06,309 --> 00:19:08,070
then we send the phantom back to Ileana.

497
00:19:08,070 --> 00:19:08,730
And Ileana

498
00:19:09,029 --> 00:19:11,445
analyzes that and hopefully gives us the the

499
00:19:11,445 --> 00:19:12,664
green light to say that

500
00:19:13,204 --> 00:19:15,065
we're in tolerance and as expected.

501
00:19:15,845 --> 00:19:16,345
Excellent.

502
00:19:17,765 --> 00:19:18,984
Okay. And then

503
00:19:19,445 --> 00:19:20,664
researchers are also,

504
00:19:22,005 --> 00:19:25,659
developing new types of radiation treatments that sort

505
00:19:25,659 --> 00:19:28,059
of exploit the parameters of the beam for

506
00:19:28,059 --> 00:19:29,359
for specific needs.

507
00:19:29,819 --> 00:19:32,720
And one example of this is flash radiotherapy,

508
00:19:33,259 --> 00:19:35,039
which is an emerging technique

509
00:19:35,515 --> 00:19:37,855
in which the radiation is delivered at extremely

510
00:19:37,914 --> 00:19:39,914
high dose rates in a fraction of a

511
00:19:39,914 --> 00:19:40,414
second.

512
00:19:40,875 --> 00:19:42,315
And this is a very new thing, but

513
00:19:42,315 --> 00:19:44,474
how does this really fast treatment, how does

514
00:19:44,474 --> 00:19:45,214
this help?

515
00:19:46,154 --> 00:19:49,134
Everybody's talking about flash and other new modalities.

516
00:19:49,275 --> 00:19:51,059
And I I think from my point of

517
00:19:51,059 --> 00:19:52,279
view, it it promises

518
00:19:52,660 --> 00:19:55,079
that it will reduce normal tissue toxicity.

519
00:19:55,539 --> 00:19:57,539
That's one of the main uptakes of why

520
00:19:57,539 --> 00:19:58,839
everybody thinking that.

521
00:19:59,140 --> 00:20:00,900
From other point of view is that it

522
00:20:00,900 --> 00:20:03,059
will the treatment could be delivered in a

523
00:20:03,059 --> 00:20:04,005
very, very short

524
00:20:04,884 --> 00:20:06,565
time, which it will help in many ways.

525
00:20:06,565 --> 00:20:07,305
For instance,

526
00:20:07,684 --> 00:20:09,464
problems associated to eye mobilization.

527
00:20:09,765 --> 00:20:11,525
If you are delivering the treatment in a

528
00:20:11,525 --> 00:20:12,825
very short period of time,

529
00:20:13,125 --> 00:20:15,365
this problem with eye mobilization of the patient

530
00:20:15,365 --> 00:20:16,105
or movements

531
00:20:16,404 --> 00:20:18,599
during the treatment will be reduced, of course.

532
00:20:19,240 --> 00:20:19,740
But

533
00:20:20,679 --> 00:20:23,160
it is, in my opinion, at early stage,

534
00:20:23,160 --> 00:20:24,940
it's a very complicated

535
00:20:25,559 --> 00:20:26,059
technologically

536
00:20:26,519 --> 00:20:27,179
and mostly

537
00:20:27,640 --> 00:20:28,140
dosimetry,

538
00:20:28,519 --> 00:20:30,380
establishing a transverse dosimetry

539
00:20:31,105 --> 00:20:32,704
to determine that the dose you are giving

540
00:20:32,704 --> 00:20:34,944
to the patient is the adequate, is proven

541
00:20:34,944 --> 00:20:35,444
challenging.

542
00:20:35,904 --> 00:20:38,384
And there are still physicists around the world

543
00:20:38,384 --> 00:20:40,404
and other scientists and other,

544
00:20:41,264 --> 00:20:42,724
members of this multidisciplinary

545
00:20:43,264 --> 00:20:45,180
team trying to understand what is the best

546
00:20:45,820 --> 00:20:46,539
way to,

547
00:20:47,660 --> 00:20:50,140
deliver this type of treatment in a safe

548
00:20:50,460 --> 00:20:53,740
safer way? Flash radiotherapy techniques are actually being

549
00:20:53,740 --> 00:20:55,580
used on patients at the moment through through

550
00:20:55,580 --> 00:20:56,720
some clinical trials.

551
00:20:57,340 --> 00:20:59,205
So as Leanna said, there's there's been lots

552
00:20:59,205 --> 00:21:00,984
and lots of interest in this. Initially,

553
00:21:01,365 --> 00:21:04,404
it started using conventional linear accelerators, but they're

554
00:21:04,404 --> 00:21:07,305
electron, high energy electron treatments we could deliver.

555
00:21:07,525 --> 00:21:09,365
What we're talking about for dose rates for

556
00:21:09,365 --> 00:21:12,105
flash? Well, our standard radiotherapy, we're typically

557
00:21:12,539 --> 00:21:15,259
delivering about five gray of dose in a

558
00:21:15,259 --> 00:21:18,059
minute. This is talking about delivering greater than

559
00:21:18,059 --> 00:21:19,759
forty gray in a second.

560
00:21:21,100 --> 00:21:23,740
But with animal studies, there was promising results.

561
00:21:23,740 --> 00:21:25,625
It was showing that there was a reduction

562
00:21:25,845 --> 00:21:28,805
in the normal tissue complication, the normal tissue

563
00:21:28,805 --> 00:21:29,305
effects,

564
00:21:29,845 --> 00:21:31,945
but no change in the tumor control.

565
00:21:33,684 --> 00:21:35,305
And they did lots of experiments

566
00:21:35,765 --> 00:21:38,980
with monkey, pig, and cats, And, actually, in

567
00:21:38,980 --> 00:21:41,299
France in 2019, they used it to treat,

568
00:21:41,539 --> 00:21:43,880
a recurrent skin lesion on a patient,

569
00:21:44,339 --> 00:21:44,839
and

570
00:21:45,220 --> 00:21:47,240
the result was was very good.

571
00:21:48,819 --> 00:21:52,005
And proton therapy, there's lots of excitement about

572
00:21:52,644 --> 00:21:54,884
potential flash with proton therapy. So one of

573
00:21:54,884 --> 00:21:55,625
the vendors

574
00:21:56,005 --> 00:21:58,644
has bit, got a group together working on

575
00:21:58,644 --> 00:22:00,884
that. And in The United States, there are

576
00:22:00,884 --> 00:22:03,204
now a couple of trials called the fast

577
00:22:03,204 --> 00:22:05,250
zero one and the fast zero two trial,

578
00:22:05,329 --> 00:22:07,029
which is looking at using proton,

579
00:22:07,730 --> 00:22:08,710
flash radiotherapy,

580
00:22:09,730 --> 00:22:11,589
on patients who have painful

581
00:22:11,970 --> 00:22:12,950
bone metastases

582
00:22:13,650 --> 00:22:16,529
that we know that other conventional techniques are

583
00:22:16,529 --> 00:22:18,069
not so good at treating.

584
00:22:18,974 --> 00:22:21,375
And there's also a trial I've just heard

585
00:22:21,375 --> 00:22:24,414
about last week, LAANC. It's a randomized phase

586
00:22:24,414 --> 00:22:26,734
two trial. It's going to be using, going

587
00:22:26,734 --> 00:22:27,954
back to the electron

588
00:22:28,255 --> 00:22:30,515
treatments, but it's going to be a randomized

589
00:22:30,654 --> 00:22:31,634
trial comparing

590
00:22:32,099 --> 00:22:33,400
delivering flash radiotherapy

591
00:22:33,779 --> 00:22:35,240
with conventional radiotherapy

592
00:22:35,940 --> 00:22:36,420
for,

593
00:22:38,019 --> 00:22:39,400
BCCs and SCC

594
00:22:39,779 --> 00:22:40,519
skin cancers.

595
00:22:42,420 --> 00:22:43,240
Oh, it worked?

596
00:22:44,115 --> 00:22:45,734
People have lots of theories.

597
00:22:46,434 --> 00:22:48,134
No one's completely sure.

598
00:22:48,994 --> 00:22:50,914
One theory is it's to do with the

599
00:22:50,914 --> 00:22:53,894
oxygen, that this rapid delivery of the radiation

600
00:22:54,115 --> 00:22:57,394
induces oxygen depletion, which protects the normal tissues,

601
00:22:57,394 --> 00:22:59,589
but not the cancer cells. We know that

602
00:22:59,589 --> 00:23:02,009
tissues that are hypoxic, that have,

603
00:23:04,069 --> 00:23:05,289
are missing oxygen,

604
00:23:06,069 --> 00:23:08,490
that this makes them more radio resistant.

605
00:23:09,029 --> 00:23:10,730
So it's thought that possibly

606
00:23:11,284 --> 00:23:13,765
the difference in the tissue toxicity may be

607
00:23:13,765 --> 00:23:15,605
due to the level of the hypoxia that

608
00:23:15,605 --> 00:23:17,524
we see at ultra high dose rates and

609
00:23:17,524 --> 00:23:18,505
subsequent radioresistance.

610
00:23:19,605 --> 00:23:22,005
It could be differences in the tissue response.

611
00:23:22,005 --> 00:23:24,005
Maybe the normal tissues are just better at

612
00:23:24,005 --> 00:23:26,744
repairing damage from a rapid burst of radiation,

613
00:23:27,390 --> 00:23:29,330
while cancer cells are maybe more vulnerable.

614
00:23:30,190 --> 00:23:32,430
And possibly, it could be a modified immune

615
00:23:32,430 --> 00:23:35,089
response because of the shorter treatment times.

616
00:23:36,029 --> 00:23:37,390
There's lots of theories out there at the

617
00:23:37,390 --> 00:23:38,769
moment. We're not sure.

618
00:23:39,150 --> 00:23:41,034
So lots of work to be done finding

619
00:23:41,034 --> 00:23:42,914
out why it works, but but it it

620
00:23:42,914 --> 00:23:43,815
sounds promising.

621
00:23:45,875 --> 00:23:47,575
So there's another technique

622
00:23:47,875 --> 00:23:49,555
that sort of tries to do a similar

623
00:23:49,555 --> 00:23:52,275
thing, I. E. Prevent the damage to normal

624
00:23:52,275 --> 00:23:52,775
tissue,

625
00:23:53,315 --> 00:23:55,910
and that's the use of mini beams or

626
00:23:55,910 --> 00:23:56,809
micro beams.

627
00:23:57,269 --> 00:24:00,150
And here, the, treatment beam is split up

628
00:24:00,150 --> 00:24:03,589
into an array of tiny, thin radiation beams

629
00:24:03,589 --> 00:24:04,730
that create alternating

630
00:24:05,750 --> 00:24:07,670
peaks of high dose and then low dose

631
00:24:07,670 --> 00:24:08,170
valleys.

632
00:24:08,765 --> 00:24:11,484
So, again, what how could this help improve

633
00:24:11,484 --> 00:24:12,384
cancer treatment?

634
00:24:13,325 --> 00:24:15,744
Actually, it's not so such a new thing.

635
00:24:16,765 --> 00:24:18,144
Already when the kV

636
00:24:18,605 --> 00:24:19,904
radiotherapy started,

637
00:24:20,845 --> 00:24:23,069
right after the discovery of the X rays,

638
00:24:23,230 --> 00:24:24,909
there was the use of this so called

639
00:24:24,909 --> 00:24:27,250
grid therapy where radiotherapies

640
00:24:27,630 --> 00:24:29,649
were trying to protect the skin

641
00:24:30,190 --> 00:24:32,829
by when they needed to irradiate tumors that

642
00:24:32,829 --> 00:24:35,250
were a little bit below the skin's surface,

643
00:24:35,515 --> 00:24:37,775
and that created that the same type of

644
00:24:38,394 --> 00:24:41,434
dose distribution. So protecting and trying to protect

645
00:24:41,434 --> 00:24:43,755
the toxicity that the skin will deliver. So

646
00:24:43,755 --> 00:24:45,674
it's not something so new. It's just that

647
00:24:45,674 --> 00:24:46,174
now,

648
00:24:46,554 --> 00:24:47,375
we are technologically

649
00:24:47,835 --> 00:24:48,654
better prepared

650
00:24:49,750 --> 00:24:50,569
to be more,

651
00:24:51,269 --> 00:24:52,730
aware of what could be

652
00:24:53,269 --> 00:24:54,569
the way of implementing

653
00:24:54,869 --> 00:24:57,029
this that is safer for the patient and

654
00:24:57,029 --> 00:24:58,970
more in a more controlled way.

655
00:24:59,430 --> 00:25:01,849
So, and that they have been intent

656
00:25:02,869 --> 00:25:04,125
to implementing this

657
00:25:05,325 --> 00:25:06,865
mini wings or with protons,

658
00:25:08,924 --> 00:25:11,484
with, basically at the moment with protons with

659
00:25:11,484 --> 00:25:13,325
m v too, but it's a little bit

660
00:25:13,325 --> 00:25:15,244
more complicated because then you have to have,

661
00:25:15,244 --> 00:25:18,929
like, that sort of collimators that could be

662
00:25:18,929 --> 00:25:20,929
difficult to design or difficult to use at

663
00:25:20,929 --> 00:25:23,029
the moment, but it's it's it's

664
00:25:25,730 --> 00:25:28,609
proven that it's something that will benefit. And

665
00:25:28,609 --> 00:25:30,769
in my opinion, but I might be not

666
00:25:30,769 --> 00:25:33,255
totally right, it will benefit patients that has

667
00:25:34,134 --> 00:25:34,714
like huge

668
00:25:35,095 --> 00:25:36,714
bulk tumor tumors

669
00:25:37,015 --> 00:25:38,075
because the the,

670
00:25:38,855 --> 00:25:42,055
presence of this up scope abscopal effect and

671
00:25:42,055 --> 00:25:43,974
bystander effect can,

672
00:25:44,375 --> 00:25:46,615
help that even though you are delivering a

673
00:25:46,615 --> 00:25:47,994
dose to a gray area,

674
00:25:48,329 --> 00:25:50,890
this information that is missed passed is passed

675
00:25:50,890 --> 00:25:53,549
between cells that are irradiated or not irradiated

676
00:25:54,009 --> 00:25:55,950
can contribute to a better

677
00:25:56,730 --> 00:25:58,890
control of the tumor and also a sparing

678
00:25:58,890 --> 00:25:59,950
of the healthy tissue

679
00:26:00,375 --> 00:26:02,855
without affecting the dose delivered to the tumor.

680
00:26:03,174 --> 00:26:04,855
So I I think it's something new as

681
00:26:04,855 --> 00:26:04,934
well.

682
00:26:05,734 --> 00:26:07,035
And there is not a clear

683
00:26:08,214 --> 00:26:09,355
yet pipeline

684
00:26:10,134 --> 00:26:12,375
of how to introduce it, although there are

685
00:26:12,375 --> 00:26:12,875
being

686
00:26:14,309 --> 00:26:16,309
papers published is about how could be the

687
00:26:16,309 --> 00:26:17,130
way to

688
00:26:19,349 --> 00:26:22,390
perform clinical trials that demonstrates the validity of

689
00:26:22,390 --> 00:26:23,130
these techniques.

690
00:26:23,509 --> 00:26:25,849
So it's it's that that's what my understanding

691
00:26:25,990 --> 00:26:29,585
of at the moment of this technique, mini

692
00:26:29,585 --> 00:26:31,825
beans. But I'm so saying actually interesting, sorry

693
00:26:31,825 --> 00:26:33,984
that I extended myself a little bit, but

694
00:26:33,984 --> 00:26:35,285
NPL is going to,

695
00:26:36,464 --> 00:26:37,445
in in between,

696
00:26:37,825 --> 00:26:38,484
at at

697
00:26:39,105 --> 00:26:41,569
mid March, is going to be a workshop

698
00:26:41,630 --> 00:26:43,809
on spatial fractionation radiotherapy

699
00:26:44,349 --> 00:26:45,730
or mini beam radiotherapy.

700
00:26:46,029 --> 00:26:46,529
Well,

701
00:26:47,309 --> 00:26:50,589
physicists, mostly physicists, some clinicians as well from

702
00:26:50,589 --> 00:26:51,569
Europe mostly

703
00:26:51,950 --> 00:26:54,289
are going to present their results in this,

704
00:26:54,974 --> 00:26:57,295
and the from the dosimetry point of view,

705
00:26:57,295 --> 00:26:59,694
but also the idea will be to establish

706
00:26:59,694 --> 00:27:02,174
maybe a road map on how to,

707
00:27:02,734 --> 00:27:06,194
introduce this, how to get to better

708
00:27:06,654 --> 00:27:09,214
organization or how to introduce this technique into

709
00:27:09,214 --> 00:27:09,714
the

710
00:27:10,140 --> 00:27:11,599
normal clinical environment.

711
00:27:12,539 --> 00:27:14,460
Lots of results out there from our animal

712
00:27:14,460 --> 00:27:16,000
experiments. That's promising

713
00:27:16,380 --> 00:27:18,859
and has shown an improvement in tolerance of

714
00:27:18,859 --> 00:27:21,359
normal tissues, particularly brain and skin tissue.

715
00:27:21,740 --> 00:27:23,695
To withstand peak doses as high as a

716
00:27:23,695 --> 00:27:26,015
hundred and a 50 gray. You know, when

717
00:27:26,015 --> 00:27:28,035
conventional radiotherapy, we're only

718
00:27:28,335 --> 00:27:29,955
going as high as seventy,

719
00:27:30,335 --> 00:27:31,154
eighty gray.

720
00:27:31,695 --> 00:27:34,414
So there's hope that this will allow us

721
00:27:34,414 --> 00:27:36,494
to be safely be able to escalate the

722
00:27:36,494 --> 00:27:38,275
dose that we give to these radioresistant

723
00:27:38,654 --> 00:27:40,309
tumors, these tumors that we know that we

724
00:27:40,309 --> 00:27:42,330
we struggle to completely control.

725
00:27:44,230 --> 00:27:46,230
K. So there seems to be some various

726
00:27:46,230 --> 00:27:49,750
ways to use the radiation beams in different

727
00:27:49,750 --> 00:27:50,250
ways,

728
00:27:50,950 --> 00:27:52,490
for different types of treatment.

729
00:27:52,894 --> 00:27:55,214
Are there any medical therapies that use much

730
00:27:55,214 --> 00:27:56,914
lower doses of radiation?

731
00:27:58,575 --> 00:28:00,994
At Dartmouth, for many, many years, we we've

732
00:28:01,454 --> 00:28:04,974
treated patients with total body irradiation and total

733
00:28:04,974 --> 00:28:05,954
lymph node irradiation,

734
00:28:06,470 --> 00:28:08,730
and this is, as part of the preparation

735
00:28:09,109 --> 00:28:11,190
regimen for patients who are going to have

736
00:28:11,190 --> 00:28:13,829
bone marrow transplant. And for these patients, because

737
00:28:13,829 --> 00:28:14,650
we're irradiating

738
00:28:14,950 --> 00:28:17,450
the whole of their body, we we're delivering

739
00:28:17,589 --> 00:28:18,329
very low

740
00:28:18,710 --> 00:28:21,349
doses in in total and low dose per

741
00:28:21,349 --> 00:28:21,849
fraction.

742
00:28:22,365 --> 00:28:22,865
And

743
00:28:23,964 --> 00:28:26,464
the reason we're doing this is we're

744
00:28:27,085 --> 00:28:28,684
patients who are going to have a stem

745
00:28:28,684 --> 00:28:30,545
cell transplant and bone marrow transplant,

746
00:28:31,085 --> 00:28:32,384
their own body

747
00:28:32,765 --> 00:28:35,210
is immune system may say see these cells

748
00:28:35,210 --> 00:28:36,750
as foreign and attack it,

749
00:28:37,529 --> 00:28:39,369
and the immune system will destroy them, and

750
00:28:39,369 --> 00:28:41,609
then that transplant will fail. So by having

751
00:28:41,609 --> 00:28:45,070
this low dose radiation treatment before you transplant

752
00:28:45,289 --> 00:28:46,990
can help keep that from happening,

753
00:28:47,845 --> 00:28:50,244
and it's thought to be immune enhancement rather

754
00:28:50,244 --> 00:28:52,184
than direct radiation cell killing,

755
00:28:52,884 --> 00:28:55,524
that enables it to have this effect. So

756
00:28:55,524 --> 00:28:57,304
we've been doing that for a long time,

757
00:28:57,845 --> 00:28:59,605
but there's also growing interest in the use

758
00:28:59,605 --> 00:29:01,865
of low dose radiotherapy for pain relief

759
00:29:02,200 --> 00:29:03,019
for noncancerous

760
00:29:03,320 --> 00:29:03,820
diseases.

761
00:29:04,279 --> 00:29:06,279
So I'm sure there's probably people out there

762
00:29:06,279 --> 00:29:07,820
who've seen there's been a couple of documentaries

763
00:29:08,039 --> 00:29:09,420
on Usain Bolt,

764
00:29:10,039 --> 00:29:11,340
the Olympic sprinter.

765
00:29:11,720 --> 00:29:13,900
He had some low dose radiotherapy

766
00:29:14,200 --> 00:29:14,700
treatment,

767
00:29:15,075 --> 00:29:16,914
for tendonitis. I think it was in in

768
00:29:16,914 --> 00:29:19,255
his ankle, and as a result of that

769
00:29:19,315 --> 00:29:21,575
went on and, won more gold medals.

770
00:29:21,875 --> 00:29:23,954
It's been practiced for many, many years in

771
00:29:23,954 --> 00:29:24,454
Germany,

772
00:29:24,755 --> 00:29:25,575
and Austria,

773
00:29:26,115 --> 00:29:28,375
and it's a widely emerging treatment for inflammatory

774
00:29:28,674 --> 00:29:29,494
joint diseases,

775
00:29:30,279 --> 00:29:30,779
osteoarthritis,

776
00:29:31,240 --> 00:29:34,299
tendonitis. It's been proposed as potential treatment for,

777
00:29:34,759 --> 00:29:37,980
lung complications from COVID, potentially for Alzheimer's.

778
00:29:38,920 --> 00:29:41,240
It uses very low doses of radiation, so

779
00:29:41,240 --> 00:29:42,299
whereas in conventional

780
00:29:42,765 --> 00:29:44,224
radiotherapy we're delivering,

781
00:29:45,005 --> 00:29:47,184
fractions of about two grey

782
00:29:47,565 --> 00:29:50,865
over daily, over several weeks, this is delivering

783
00:29:51,565 --> 00:29:53,884
a half a grey to one grey per

784
00:29:53,884 --> 00:29:54,384
fraction,

785
00:29:54,779 --> 00:29:56,700
to a total dose of two or six

786
00:29:56,700 --> 00:29:58,559
gray, only about six treatments,

787
00:30:00,940 --> 00:30:02,559
and it's been shown to

788
00:30:03,180 --> 00:30:04,960
reduce pain and the inflammation.

789
00:30:06,059 --> 00:30:10,174
The therapeutic mechanism is always it's complicated, multifaceted,

790
00:30:10,554 --> 00:30:11,615
not fully understood,

791
00:30:12,315 --> 00:30:14,815
but it's thought it's got some immune effects

792
00:30:15,034 --> 00:30:16,095
and anti inflammatory

793
00:30:16,554 --> 00:30:17,054
effects,

794
00:30:17,914 --> 00:30:20,255
and potentially it's leading to an enhanced

795
00:30:21,619 --> 00:30:24,259
immune surveillance. So it's kind of triggering the

796
00:30:24,259 --> 00:30:27,220
immune system to recognize that there's there's something

797
00:30:27,220 --> 00:30:29,400
going on and getting your own immune system

798
00:30:29,619 --> 00:30:30,200
to then

799
00:30:30,820 --> 00:30:31,860
correct the,

800
00:30:32,420 --> 00:30:33,615
the issue that you've got.

801
00:30:34,335 --> 00:30:36,734
We do see in conventional radiotherapy actually as

802
00:30:36,734 --> 00:30:39,214
well something called the bystander effect. So there

803
00:30:39,214 --> 00:30:40,894
are reports out there in the literature of

804
00:30:40,974 --> 00:30:42,434
for example, if you've got a patient,

805
00:30:44,734 --> 00:30:47,315
and their primary tumor was treated previously

806
00:30:47,880 --> 00:30:49,720
and has been cured, but they've come back

807
00:30:49,720 --> 00:30:51,420
and they've got they may have a metastatic

808
00:30:52,200 --> 00:30:54,279
tumor in the lung and a metastatic tumor

809
00:30:54,279 --> 00:30:56,220
in the liver, and we can treat those

810
00:30:56,359 --> 00:30:57,820
using these stereotactic

811
00:30:58,359 --> 00:30:58,859
technique.

812
00:30:59,480 --> 00:31:01,275
And what they've seen in some patients is

813
00:31:01,355 --> 00:31:03,615
by treating the tumor in the lung,

814
00:31:03,994 --> 00:31:05,375
the tumor in the liver

815
00:31:05,755 --> 00:31:06,255
also

816
00:31:06,714 --> 00:31:09,695
disappears. Now it hasn't been directly irradiated,

817
00:31:10,234 --> 00:31:12,714
but possibly by treating that tumor in the

818
00:31:12,714 --> 00:31:14,730
lung it's kind of woken up the immune

819
00:31:14,730 --> 00:31:16,730
system and made it recognize that there are

820
00:31:16,730 --> 00:31:18,269
these cancer cells that

821
00:31:18,809 --> 00:31:21,049
need to be dealt with. Another area is

822
00:31:21,049 --> 00:31:22,990
now the use of low dose in diagnostics

823
00:31:23,130 --> 00:31:25,309
and nuclear medicine as part of the combined

824
00:31:25,369 --> 00:31:26,670
part of first,

825
00:31:27,130 --> 00:31:28,670
finding where is the

826
00:31:29,924 --> 00:31:30,424
radionuclide

827
00:31:30,804 --> 00:31:33,464
we which area would be targeted by radionuclide

828
00:31:33,684 --> 00:31:36,265
by using lower dose and then by specifically

829
00:31:36,804 --> 00:31:39,765
using larger dose to complement the treatment. So

830
00:31:39,765 --> 00:31:42,105
it's it's part of the so called diagnostic,

831
00:31:42,884 --> 00:31:43,625
use of

832
00:31:44,210 --> 00:31:44,710
radionuclides

833
00:31:45,170 --> 00:31:46,869
for molecular radiotherapy.

834
00:31:47,250 --> 00:31:49,970
Finally, that's sort of looking ahead into the

835
00:31:49,970 --> 00:31:50,470
future.

836
00:31:51,490 --> 00:31:53,570
How do you think radiation will continue to

837
00:31:53,570 --> 00:31:57,089
play a really essential role in medical treatments?

838
00:31:57,089 --> 00:31:58,630
How how could you see it evolving?

839
00:31:59,365 --> 00:32:00,724
I think it's still going to be with

840
00:32:00,724 --> 00:32:02,644
us and needed for a long time to

841
00:32:02,644 --> 00:32:03,944
come. Cancer incidence

842
00:32:04,484 --> 00:32:07,365
worldwide is continuing to increase. It's expected to

843
00:32:07,365 --> 00:32:09,784
be doubling by two thousand and forty.

844
00:32:10,244 --> 00:32:12,644
And radiotherapy is a highly effective treatment of

845
00:32:12,644 --> 00:32:15,220
cancer. It we know that it delivers long

846
00:32:15,220 --> 00:32:17,320
term tumor control, and it also has

847
00:32:17,859 --> 00:32:19,400
great value as palliative

848
00:32:20,019 --> 00:32:23,539
as treatment as well. So worldwide, around half

849
00:32:23,539 --> 00:32:26,019
of patients with cancer will receive some form

850
00:32:26,019 --> 00:32:26,759
of radiotherapy.

851
00:32:27,734 --> 00:32:29,674
And of those cured by cancer,

852
00:32:30,134 --> 00:32:32,075
forty percent will have had radiotherapy.

853
00:32:33,654 --> 00:32:36,134
Early detection is key. The smaller the tumor

854
00:32:36,134 --> 00:32:37,974
is, the less likely is to have spread

855
00:32:37,974 --> 00:32:40,109
and the easier it is to treat. And

856
00:32:40,109 --> 00:32:42,430
radiotherapy has the capacity to treat large number

857
00:32:42,430 --> 00:32:44,450
of patients, and it's very cost effective.

858
00:32:45,150 --> 00:32:47,789
A linear accelerator can treat 40 or 50

859
00:32:47,789 --> 00:32:49,089
patients a day.

860
00:32:49,549 --> 00:32:52,654
A single course of radiotherapy treatment typically cost

861
00:32:52,654 --> 00:32:54,494
between 3 to £7,000

862
00:32:54,494 --> 00:32:56,174
per patient when you think that a cycle

863
00:32:56,174 --> 00:32:58,595
of chemotherapy can cost 30,000.

864
00:32:59,294 --> 00:33:01,534
So, yeah, I think we're gonna be around

865
00:33:01,534 --> 00:33:03,694
for a long time to come. But how

866
00:33:03,694 --> 00:33:05,774
we deliver it, I mean, over my twenty

867
00:33:05,774 --> 00:33:08,799
plus year career, things have changed and become

868
00:33:08,799 --> 00:33:10,019
far more complex.

869
00:33:11,200 --> 00:33:12,419
We've got the modalities

870
00:33:12,799 --> 00:33:13,299
protons.

871
00:33:13,599 --> 00:33:15,599
The in The UK, we now have this

872
00:33:15,599 --> 00:33:18,259
three proton facilities. We've got the long standing

873
00:33:18,399 --> 00:33:18,899
low

874
00:33:19,244 --> 00:33:22,924
energy proton facility for treating the tumors at

875
00:33:22,924 --> 00:33:24,305
the back of the eye at the Clatterbridge,

876
00:33:25,085 --> 00:33:27,664
and also the two high energy proton facilities,

877
00:33:27,884 --> 00:33:29,484
the one in Manchester at the Christi and

878
00:33:29,484 --> 00:33:31,105
the one at University College,

879
00:33:31,404 --> 00:33:32,144
in London.

880
00:33:32,900 --> 00:33:35,539
So I I think we will change. Different

881
00:33:35,539 --> 00:33:38,440
tumor types will be treated with different modalities.

882
00:33:38,659 --> 00:33:40,359
I think we've learned lots about,

883
00:33:40,740 --> 00:33:43,059
our fractionation as well. We used to deliver

884
00:33:43,059 --> 00:33:45,299
not that long ago, for example, breast cancer

885
00:33:45,299 --> 00:33:47,460
treatments would be a five week course of

886
00:33:47,460 --> 00:33:47,960
treatment.

887
00:33:48,644 --> 00:33:50,884
Now through clinical trials, we've shown that we

888
00:33:50,884 --> 00:33:54,005
can deliver as effective treatment over just five

889
00:33:54,005 --> 00:33:56,184
treatments. I think those things will change,

890
00:33:57,125 --> 00:33:58,805
but I certainly expect to,

891
00:33:59,845 --> 00:34:02,904
be long retired and there still be radiotherapy

892
00:34:03,205 --> 00:34:03,705
treatments.

893
00:34:04,769 --> 00:34:06,370
Yeah. I I I think I also it

894
00:34:06,370 --> 00:34:07,509
will be more personalized.

895
00:34:08,050 --> 00:34:10,070
It will be include immunotherapy

896
00:34:11,170 --> 00:34:12,309
associated to radiotherapy.

897
00:34:12,849 --> 00:34:15,170
So finding the gene, the proper gene of

898
00:34:15,170 --> 00:34:17,030
this your tumor, the

899
00:34:17,635 --> 00:34:19,655
person's tumor, and then the

900
00:34:20,114 --> 00:34:22,695
using radiotherapy in combination with this

901
00:34:22,994 --> 00:34:23,494
immunotherapy

902
00:34:23,875 --> 00:34:25,555
agent with with this,

903
00:34:27,235 --> 00:34:28,835
the in in a way that I think

904
00:34:28,835 --> 00:34:31,315
radiotherapy will be at at at some point

905
00:34:31,315 --> 00:34:31,815
personalized

906
00:34:32,195 --> 00:34:32,934
to the patient.

907
00:34:33,690 --> 00:34:35,389
That will maybe increase the

908
00:34:36,089 --> 00:34:38,909
cost of cryotherapy, but the benefits will be,

909
00:34:39,449 --> 00:34:40,030
I think,

910
00:34:41,690 --> 00:34:43,230
great for the patient

911
00:34:43,530 --> 00:34:45,769
as well as all the introduction of this

912
00:34:45,769 --> 00:34:47,835
flash that we talk about, the mini beams.

913
00:34:48,234 --> 00:34:50,474
It would be forever there. I believe that

914
00:34:50,474 --> 00:34:52,954
too, that cryotherapy is not going to as

915
00:34:52,954 --> 00:34:54,494
long as there there is cancer

916
00:34:55,034 --> 00:34:56,894
and cancer needs to be treated,

917
00:34:57,195 --> 00:34:58,175
I think cryotherapy

918
00:34:59,675 --> 00:35:00,494
will be there.

919
00:35:01,920 --> 00:35:04,639
Excellent. Well, thank you very much to both

920
00:35:04,639 --> 00:35:06,500
of you. Thanks for joining us today.

921
00:35:14,244 --> 00:35:17,625
That was Physics World's Tammy Freeman in conversation

922
00:35:17,844 --> 00:35:18,664
with NPL's

923
00:35:19,364 --> 00:35:19,864
Ileana

924
00:35:20,244 --> 00:35:20,744
Silvestra

925
00:35:21,045 --> 00:35:21,545
Patello

926
00:35:21,925 --> 00:35:23,224
and Ruth McLaughlin

927
00:35:23,605 --> 00:35:24,824
who is at Imperial

928
00:35:25,204 --> 00:35:26,264
College Healthcare

929
00:35:26,565 --> 00:35:27,704
NHS Trust.

930
00:35:28,099 --> 00:35:30,280
Thanks to all three for a fascinating

931
00:35:30,579 --> 00:35:31,079
conversation,

932
00:35:31,619 --> 00:35:34,659
and a special thanks to Fred Ailes, who

933
00:35:34,659 --> 00:35:36,599
is our audio engineer.

934
00:35:37,380 --> 00:35:40,840
This episode was created in collaboration with IPEM,

935
00:35:41,405 --> 00:35:45,105
the Institute of Physics and Engineering in Medicine.

936
00:35:45,804 --> 00:35:47,585
IPEM owns the journal

937
00:35:47,885 --> 00:35:50,224
Physics in Medicine and Biology.

938
00:35:51,324 --> 00:35:51,824
Raucous,

939
00:35:52,284 --> 00:35:53,905
diverse, and loud,

940
00:35:54,420 --> 00:35:58,039
That's how the philosopher and physics world columnist

941
00:35:58,339 --> 00:35:59,400
Robert Kress

942
00:35:59,780 --> 00:36:02,760
described the stand up for science demonstration

943
00:36:03,539 --> 00:36:04,359
at Washington

944
00:36:04,739 --> 00:36:08,280
Square Park in New York City on Friday,

945
00:36:08,579 --> 00:36:10,119
March.

946
00:36:10,715 --> 00:36:12,474
This was one of 32

947
00:36:12,474 --> 00:36:15,934
similar events across The US where participants

948
00:36:16,315 --> 00:36:17,855
gathered to protest

949
00:36:18,315 --> 00:36:19,934
planned cuts to key

950
00:36:20,315 --> 00:36:20,815
scientific

951
00:36:21,114 --> 00:36:21,614
agencies

952
00:36:21,914 --> 00:36:22,735
in the country.

953
00:36:23,420 --> 00:36:25,900
When he was there, Bob spoke to the

954
00:36:25,900 --> 00:36:29,119
organizer of the New York event and also

955
00:36:29,180 --> 00:36:30,640
to several protesters.

956
00:36:31,420 --> 00:36:33,519
And in an article, he shares

957
00:36:33,820 --> 00:36:36,815
some of the clever slogans that were chanted

958
00:36:37,195 --> 00:36:39,054
and appeared on placards

959
00:36:39,434 --> 00:36:40,335
at the protest.

960
00:36:40,954 --> 00:36:43,594
You can read Bob's article on the Physics

961
00:36:43,594 --> 00:36:44,414
World website.

962
00:36:45,034 --> 00:36:46,335
Just look for the headline,

963
00:36:46,954 --> 00:36:47,454
Demonstrators

964
00:36:47,994 --> 00:36:49,135
March for Science

965
00:36:49,619 --> 00:36:50,920
in New York City.

966
00:36:51,619 --> 00:36:53,539
I'm afraid that's all the time we have

967
00:36:53,539 --> 00:36:54,759
for this week's podcast.

968
00:36:55,219 --> 00:36:57,719
I'll be back next week in conversation

969
00:36:58,179 --> 00:36:59,880
with the quantum cryptography

970
00:37:00,339 --> 00:37:00,839
pioneer,

971
00:37:01,460 --> 00:37:02,519
Arthur Eckert.