Yutong Zhao: A Brilliant Master Graduate and Our New PhD Candidate at UWA Medical Physics Team

Updated: Oct 2, 2021

Today we are going to introduce Yutong Zhao, one of our master graduates, who has just started a PhD in our group this week.

The title of Yutong’s masters project was: “Towards optimal SABR margins in prostate radiation therapy” under supervision of Dr Shahin Fattahi from Genesis Cancer Care, Adj/Prof Martin Ebert from the Radiation Oncology Department at SCGH, Dr David Waterhouse and Simon Goodall both from Genesis Cancer Care.

Yutong’s PhD will be on “Practical implementation of prostate cancer radiotherapy based on tumour biological characterization” under supervision of Adj Prof Martin A. Ebert, Dr Pejman Rowshanfarzad, Dr Darren Grasso, and Prof Annette Haworth.

We wish Yutong all the best in his new research journey!

Here are some comments from Dr. Pejman Rowshanfarzad who was Yutong’s coordinator and lecturer during his masters.

“Yutong is hard working, focussed, responsible and dutiful. He communicates well with his supervisors and presents his work regularly and on time.

Yutong has received High Distinction in his master’s research. He is going to be the first author on a manuscript in preparation for a peer-reviewed journal. This demonstrates his high level of motivation and enthusiasm.

Yutong’s work was presented in the Engineering and Physical Sciences in Medicine (EPSM) conference in November 2020.”

And here are Yutong’s supervisor, Prof. Martin Ebert’s comments:

“Yutong is very enthusiastic about Medical Physics and it was a pleasure to watch him plan out his MSc project, work with clinical staff to implement it and then put his results together in his final report. Yutong’s enthusiasm is infectious and the group is always keen to hear updates from him – he has a wonderful sense of humour and maintains a positive outlook, even when results are not going the way he would like.

I am looking forward to continuing to work with Yutong during his PhD.”

Yutong kindly accepted to answer a few questions about his experience in our Medical Physics research Group.

Introduction and your current position and role:

I just completed my master degree and I have been accepted to start a PhD in medical physics at UWA.

What did you enjoy most about UWA, and Medical Physics research group?

I really enjoy the time I spend in UWA libraries, both UWA libraries are fabulous, there are quiet environment, nice learning atmosphere and fast network. My friends and I spend a lot of time over there doing our assignments and discussing problems.

All my memory about UWA medical physics research group is happy and warm. My friends in other universities always complain about their supervisors who abuse power and tutors without responsibility, I am totally sympathetic to their situation I feel really sorry for the mental damage they suffered. That is the reason I extremely value and appreciate the knowledgeable supervisors, responsible tutors and easy-going classmates I have in the medical physics research group.

And in the research group, you could see there are so many talented students coming up with their fascinating research and brilliant ideas, multiple research topics would be included from immunotherapy to flash radiotherapy, from 3D printing to deep learning.

Can you give us your top three reasons to study Medical Physics?

1. Using the radiation in the medical field is soooooo cool. I don’t think this part needed more explanation, imagine how poor superheroes gained their superpower.

2. I personally worked in the hospital for a while as an intern, I saw patients were tortured by cancer and side effects and I heard their relatives crying in the corridor. There are so many improvements that could be done in the radiotherapy and medical diagnosis. I believe any improvement could potentially change the fate of a desperate family.

3. Any dreams need material support, no one can simply use love to accelerate electrons. In my understanding, before the invention of a mature immunotherapy method, both medical physicists and radiation therapists are well-paid jobs.

How do you feel you have made a difference in your field of research?

At this stage of my life, I don’t expect to achieve something huge, since I am just a novice in the field of scientific research. It would be great if I could be a not very necessary gearwheel of the big machine. However, with the increasing knowledge and experience I gained, the day I change the field and achieve something significant definitely will come soon.

What is your best advice to current students and Medical Physics applicants?

Romain Rolland says, “There is only one heroism in the world: to see the world as it is, and to love it.” What is the reality of the world? There are various explanations, but I personally think It means that a person breaks the previous ideals and dreams in the process of growing up, and finally recognizes the reality that his abilities are limited. So, if there is any advice I could give to you, I will recommend people embrace the reality of the world as it is, but believe in what it should be, don’t be disappointed and be the hero of yourself.

Here is Yutong’s master thesis abstract:

Abstract

Introduction: The planning organ at risk volumes (PRVs) is tissue volume which accounts for geometric uncertainty of organ at risk (OARs) in the radiotherapy treatment process. The PRVs could be created by drawing a margin around OARs, and this idea was addressed by ICRU Report 62. For the prostate cancer radiotherapy, especially for the prostate cancer Stereotactic Ablative Body Radiotherapy (SABR), the PRV margins are highly recommended to be applied on OARs such as bladder and rectum. Through using PRV margins, the OARs motion can be fully considered in the treatment planning stage; therefore, the treatment planner could decrease radiation dose to ORAs by reducing radiation dose to PRV margins area of OARs. This project is aiming to measure the bladder and rectum motion so to find a way to generate proper PRV margins for bladder and rectum in prostate cancer radiotherapy.

Method: This project contoured bladder and rectum of 16 patients on CBCT and CT images. Through comparing CBCT organ contour and CT organ contour, the bladder wall and rectum wall inter-fraction displacement distance could be measured. Then an investigation about wall position distribution pattern was conducted. Finally, the PRV margin recipe was created and used to generate bladder and rectum PRV margins.

Result: From the studied cases in this project, we found generally the posterior and anterior directions of bladder wall would experience a larger outward displacement than other directions. This project demonstrates that for the bladder, a PRV margin with size of 0.75 cm in right and left directions, 1 cm in anterior direction, 0.8 cm in posterior direction, and 0.55 cm in inferior direction could cover at least 90% of bladder motion for 90% (14/15) of patients. However, if the effective bladder volume controlling method could be applied to control the bladder volume, a smaller bladder PRV margin with margin width 0.6 cm (right), 0.65 cm (left), 1 cm (anterior), 0.8 cm (posterior), and 0.45 cm (inferior) could be used to cover at least 90% of bladder motion for 90% (11/12) of patients. For rectum, we notice that the rectum wall displacement degree from top to bottom is getting smaller. Thus, in this project, the rectum is segmented into superior part, middle part, and lower part, and the different rectum PRV margins are given to those three different rectum regions separately. There are three rectum PRV margins were generated and tested as qualified, they could cover at least 90% of their rectum wall outward motion for 100% (13/13), 90% (12/13), and 85% (11/13) patients separately.

Conclusion: Through dose distribution investigation, the results agree that the PRV margins we generated could prevent OARs receiving potential exceed radiation dose. With more studied cases and stricter bladder and rectum volume control, it is possible to apply a smaller PRV margin with more accurate margin size. Compared with giving rectum PRV margin without any segmentation, the PRV margins based on our rectum segmentation method could improve its’ coverage to rectum motion. Hence, it is better to perform rectum segmentation before applying PRV margins.