Making a Difference with Physics and Cancer Treatment
Protons have unique physical and radiobiological properties, and so proton beam therapy offers advantages for specific cancer types. In particular, they can be shaped as narrow, focused beams that accurately target the tumour with minimal damage to healthy tissue. Although significant progress has been made in the use of particle beams for cancer treatment, further work is needed to maximize the healthcare benefits from these therapies. This is the area on which Jacinta Yap is working, within the international training network OMA. Jacinta is a Marie Curie Fellow in the QUASAR group of the University of Liverpool and is based at the Cockcroft Institute, UK.
On the 150th anniversary of the birth of twice Nobel Prize winner Marie Curie we asked Jacinta what inspired her to study accelerator science and follow in the footsteps of this great scientist.
Motivated by physics in medicine
I think my past is quite unconventional. Growing up I had an interest in maths and science but I didn’t really know what I wanted to do at university. Initially I wanted to do a science degree, but given my dad and brother’s background in mechanical engineering, my parents advised me to pursue something more practical and so I did a major in mechanical engineering.
After that I thought maybe medicine, radiology or radiation oncology. That’s when I came across medical physics, and it's got everything that I’m interested in and what motivates me: science, medicine, physics and all the technical aspects from engineering.
I wanted to use my technical expertise but also to do something that would impact people's lives directly. As a medical physicist, I will work in a hospital and interact with patients, doctors and machines, seeing first-hand the difference I am making.
Medical physicists use software to create the treatment plan for cancer patients; this involves physically marking areas on the patient's CT scan or x-ray to be irradiated later. This plan is then verified with the doctor.
A clinic is a very dynamic environment – lots of things were happening all the time, people walking in and out. There was a lot of interaction with patients and with other staff. Without a medical physicist they wouldn’t have the technical expertise they need to treat these patients. They are right at the forefront. I think that’s the type of role I would like to have.
Proton therapy improved treatment for cancer
I started at Liverpool University last October and it's been a lot of learning so far. I think the first year of your PhD is trying to find your feet, looking at different avenues to research and how you can go about things. Also a lot of reading!
There are still a lot of unanswered questions in proton therapy; it is not fully understood or substantially proven why it is better than using conventional radiotherapy. My project with the Optimisation of Medical Accelerators network is looking at both beam diagnostics and radiobiology. OMA is a great example of the international opportunities and collaborations involved in researching and advancing proton therapy.
Cancer is different for every person; it is impacted by gender, age, the type of cell, the type of tissue, what stage the cell is at – there are so many factors.
There are many treatments for cancer – chemotherapy, immunotherapy etc – and it has to be personalised to the specific cancer, the symptoms and the organs.
It's very difficult to pinpoint exactly why proton therapy is effective overall, because there are so many different factors. One thing that is agreed is that proton therapy can do more DNA damage to the cancer. If you compare the damage with other types of radiation you can see that cells are slower to repair.
We are trying to figure out why proton therapy does more cluster damage, why this makes it harder to repair, or if it creates more strand breaks… basically pairing up the physics with the biology.
Optimising the beam for therapy
With proton therapy you need a very precise beam to ensure that the dose is delivered very accurately.
We are developing a detector that would measure the proton beam in real time, without interfering with it, and that can be installed in a hospital therapy room.
Currently the beam is measured by going through ionisation chambers: this degrades the beam and makes it spread. Our device aims to provide the same information with minimal interference to the beam where, by measuring and analysing the beam halo, the particles outside of the beam, we can figure out what the beam is actually doing as well as its properties.
There is a lot of work to be done before the beam is actually used on a patient. In hospitals they have detectors to measure the beam before and after the patient is treated, for quality assurance. From this they can double check that everything is fine, but it is not in real time.
Simulations use software to predict through complex equations what happens with to the beam when the treatment takes place. It's quite heavy coding: there are a lot of different properties and parameters that you can input into these equations to figure out how the beam will behave.
You still need the monitoring devices because that’s what actually tells you what is happening with the beam, whereas the simulation is just an equation that gives you a result, it's not necessarily reflective of what's actually happening.
Together these approaches will allow us to develop a new, non-interceptive method of online beam monitoring; this will improve the accuracy of proton cancer therapy.
Being a woman in science
Coming from engineering I've always been one of the few women. Although I'm lucky – I haven’t really experienced much discrimination in the field. I think it’s a good challenge and when you work with other women there is a bond.
Being a woman in this field can be quite valuable. I find that sometimes I can think of different areas or different ideas that other people have not thought of before. It brings another perspective to a lot of things.
There are quite a lot of women who are prominent in medical physics, so that’s been really cool. I always find it inspiring when I see women who have done so much for their particular field. In proton therapy itself quite a few women publish in a lot of prominent journals, and have higher up roles. Within the OMA project, Katia Parodi comes to mind: she heads one of the partner institutions.
Inspired by Marie Curie
I was actually recently in Krakow, where there has been a long established university, the university Marie Curie wanted to go to. At that time they didn’t accept women so she went to France.
For me, I think Marie Curie represents courage; she was able to overcome all these challenges and to pursue something fearlessly.
She is probably the first prominent female researcher who has done really incredible things, and it's because of her legacy that people like me are able to come overseas and pursue our own dreams. She is an inspiration.