Thanks to social developments, social welfare improvements and medical technology advancements, life expectancies of both sexes have steadily increased in the past decades. However, cancer, which costs most lives, is becoming more prevalent than before. Radiotherapy is one of the three pillars of cancer treatment. It is estimated that about 40% of the cancer patients are cured by radiotherapy or a combination with other methods1.
Throughout the whole radiotherapy treatment journey - from screening to diagnosis, staging to therapy suggestions, treatment planning to on-couch treatment, a multidisciplinary team that includes oncologists, radiologists, nurses and radiotherapists will be required. While the patient is experiencing a reassuring treatment journey, medical physicists are another group of medical professionals behind the scene to assure the quality of the treatment.
What do Medical Physicists do?
Medical physicists specialise in applying the principles and methods of engineering, physics and medicine on prevention, diagnosis and treatment, especially in the cancerous area. Those who are willing to engage in the medical field and are devoted to these disciplines will find their place in medical physics.
Medical physicists are responsible for ensuring quality service, providing clinical consultation and technology, as well as doing research on the industry development. The main areas in medical physics include engineering physics, health physics, imaging physics and radiotherapy physics.
Most of the time, medical physicists work at the backstage together with other medical professionals. They regularly work with technicians to ensure that the high-tech and high-precision radiotherapy machines are functioning as expected and following the international and local protocols, standards and regulations. These routine quality assurance processes are essential for assuring the quality of the therapeutic effects on patients.
For example, medical physicists will conduct the daily (usually before everyday hospital operation), weekly, monthly, quarterly and/ or annual quality check on the linear accelerator to ensure that the radiation beam output and energy are accurate, the field profile symmetry and flatness are up to standard, and the multi-leaf collimator movements are precise. The Treatment Planning System that uses parameters and characteristics of the radiation beam is a computation system that formulates a treatment course for a specific patient. Investigations and corrective maintenances shall be done immediately when a parameter is found to be out of tolerance in quality checks, otherwise the treatment courses for the patients may become useless or even develop complications.
Medical physicists also help establish local rules in hospital in handling issues related to public radiation health. For example, when ward nurses discovered that an admitted patient is implanted with radiative sources, emergency response protocol co-written by the medical physicist should be followed and implemented accordingly. Sometimes, the patient is not sure about the type of radiative source or even the presence of the radiative source implanted and no related medical records could be provided; the medical physicists shall usually assist in doing research. After gathering the basic information, follow-up actions could be introduced appropriately to avoid public radiation health risk.
Besides, medical physicists are responsible for handling various suitable advance medical technologies and machines and their corresponding software selection and acquisition. Recently, a local hospital in Hong Kong is acquiring a proton therapy machine, and two local hospitals are adopting magnetic resonance linear accelerator. At the same time, those peripheral accessories will need to be purchased. These new machines and accessories are complicated and require thorough testing and commissioning by hospital medical physicists to make sure they could be used in patients’ treatments properly.
To better perform their responsibilities, regardless of being responsible for radiation hazard management or advanced medical technologies acquisition, medical physicists have to be kept updated with the new technologies and developments. Occasionally, medical physicists have to join or even publish their research papers in international seminars, conferences and discussion forums. As medical physicists understand the theory of radiation and the machine operations well, they will share their experiences and organise lectures for the technicians and radiation therapists, and sometimes provide professional treatment advice to medical doctors.
How can I be a Medical Physicists?
Usually, the ones with biomedical engineering or physics background will be eligible to strive for a medical physicist career. Since research is part of their job duties, a master degree is the entry point for being a resident medical physicist, and indeed a doctorate will be much preferred. Resident medical physicists will receive on-the-job training and have to prepare for the professional qualification examination provided by Hong Kong Association of Medical Physics (HKAMP) or Hong Kong Institution of Physicists in Medicine (HKIPM). After accreditation, having Continuing Professional Development (CPD) to achieve professional excellence is required, as the medical industry is improving at a fast pace. Joining international seminar and conferences is also a good way to keep up with the latest technology.
You may also consider taking the postgraduate courses related to medical physics. In recent years, both overseas universities such as University College London, The University of Sydney and local universities like The University of Hong Kong and The Hong Kong Polytechnic University are providing related postgraduate courses for interested parties.
1 MOLLER, T.R., et al., A prospective survey of radiotherapy practice 2001 in Sweden, Acta Oncol. 42 (2003) 387–410.
By Mr Peter NAM from the Biomedical Division of the HKIE