Roles and responsibilities of medical physicists in oncology
Núria Jornet, from Spain, is Chair of ESTRO Physics Committee. Here she provides a fascinating insight into the work of medical physicists in oncology
It is still quite unknown by the general public and also by medical sector professionals that there are physicists working in hospitals. However, physics has interacted with medicine from the beginning of medical sciences, when physical techniques such as heat were used to treat or diagnose illnesses. The beginning of the 20th century, with the discovery of radioactivity and X-rays and their immediate application in medicine, was the birth of a new physics discipline; Medical Physics. At that time, the first posts for physicists in hospitals were linked to radiology departments and their main task was to guarantee the safe use of ionising radiation.
Today, medical physicists in hospitals can have clinical duties and/or work in research and development. Personalised medicine is largely based on imaging techniques based on physical phenomena such as ultrasounds, nuclear magnetic resonance, laser or ionising radiation. As a consequence, the main areas of clinical work are related to radiation oncology, medical imaging, nuclear medicine and radiation protection (personnel and public). In radiation oncology, medical physicists are needed to ensure that treatments are safely delivered with the highest achievable quality. As far as research and development is concerned, medical physicists have a leading role and are the driving force to further improve radiotherapy techniques and technologies.
Making the treatment plan the best it can be
Therefore, it is the responsibility of medical physicists to accept, commission and regularly control the performance of radiotherapy equipment; linear accelerators, imaging equipment for treatment simulation (CT,PET-CT, MRI), treatment planning systems. For each patient, once the radiation oncologist has defined the volume that has to be treated, the organs that have to be preserved and the treatment dose, the medical physicist will make sure that the treatment plan is the best that can be achieved with the available technology and check that the planned dose distribution is accurate and agrees with the one that is delivered. As physicists we are trained to derive the laws that rule nature from observation and analysis, so we have the background to help model tumour control and treatment toxicity.
More research-oriented medical physicists are substantially contributing to clinically relevant fields: such as the advent of biological and functional imaging, whose translation into the clinic is resulting in an improved characterisation of tumours, and more personalised treatments that will hopefully result in better survival, less toxicity and wiser use of resources.
New technologies and techniques
Medical physicists have a pivotal role in the development and safe implementation of new technologies and techniques in radiation oncology, not only regarding the treatment itself but also in many emerging fields of research and clinical services. These include:
- the individualisation of the treatments through adaptive radiotherapy
- the use of quantitative imaging for predicting response and toxicity (radiomic)
- the optimisation, validation and implementation of functional imaging
- the set up and spread of proton facilities and of MRI-Linacs
- the use of advanced methods for handling big-data to develop and validate predictive models in the actual personalised medicine scenario
- the development of pre-clinical facilities for animal experiments
- the need for better modelling of tumour kinetics
- the growing need for physics skills in controlled clinical trials and many others.
Medical physicists have a “central” position between clinic, technology development and science. Totally novel medical applications of physics in medicine continue to emerge. Probably medical physics has to evolve into fields other than radiation, such as nanoparticles, statistical physics, etc. We have the opportunity to contribute more, owing to our position and our specific and high-level scientific attitude, to the development of the cancer cures of the future.
Nuria Jornet, PhD Medical Physics, Chair of ESTRO Physics Committee, Medical Physicist at Servei de Radiofísica i Radioprotecció, Hospital Sant Pau, Barcelona (Spain)