The role of a Medical Physicist
A Medical Physicist is a holder of a Physics degree, a two-year Master’s degree in Medical Physics followed by one-year Clinical Practice. He/she receives two professional certifications by the Ministry of Health, after arduous writing exams: A professional certificate in the field of Ionizing Radiation and a professional certificate in the field of Non – Ionizing Radiation. Commonly, a Medical Physicist has also completed 3-4 year of doctoral studies with thesis topics related to medicine. Overall, a Medical Physicist is a scientist with 7 to 11 years of post-secondary education, which includes a vast amount of knowledge in medicine, biology, technology, electronics, chemistry, and information technology.
A Medical Physicist is the main person responsible for all the specifications of machines producing ionizing radiation such as radiotherapy, diagnostic and nuclear medicine units, for diagnostic or therapeutic purposes. Before the machinery installation in a hospital, the medical physicist prepares a radiation protection study on room design, shielding optimization, focusing on medical personnel and patient safety and then he/she supervises the machinery installation. The commissioning and acceptance testing is a medical physicist’s responsibility. The completion of these processes, of which the duration ranges from several days to months leads to the proper operation of the units and the Medical Physicist takes responsibility for the supervision and performance of the periodic quality controls, according to the necessity of each operating unit and the specifications of international quality control protocols.
Medical Physicist‘s role in Ionising radiation procedures
Medical Physicist‘s role in Radiotherapy
Radiotherapy is a medical act during which targeted high energy radiation is directed to cancer cells and tissues aiming the reduction and final elimination of the tumor. The Medical Physicist, as a radiation therapy oncology group member, has full responsibility of the physical – technical radiotherapy issues related to the patient, the dosimetry of the treatment unit and the safe dose delivery (taking into consideration the inevitably irradiated healthy tissues). The Medical Physicist cooperates with the Radiation Oncologist for the patient treatment, prepares or/and supervises the treatment planning and the beam arrangement in a computerised treatment planning system, aiming the tight focusing of the beams on the malignant tumor, while preserving the healthy tissues as much as possible. The Medical Physicist together with the other oncology group members ensure the precision of all the steps of the treatment procedure: Immobilisation, Image registration, Target delineation, Treatment Planning, and Radiotherapy Treatment.
The Medical Physicist’s contribution to the most modern techniques of radiotherapy (IMRT, IGRT, and VMAT) and the highly specialized radiotherapy methods such as Stereotactic Radiotherapy, is fundamental and guarantees the accurate application of them. In addition, during the therapeutic procedure which is called brachytherapy and includes radioactive materials being inserted or implanted inside the patient’s body, the Medical Physicist is responsible for the safe handling and the dosimetry of radioactive sources. The quality control protocol application and the supervision/ performance of the respective procedures by a Medical Physicist ensure the proper performance of the radiotherapy, in a precise and reproducible manner.
Medical Physicist‘s role in Nuclear Medicine
Radioactive compounds – called radiopharmaceuticals – in Nuclear Medicine, are administered to the patient (through the mouth, through inhalation or intravenously) for imaging or therapeutic purposes. During imaging, specially designed cameras (g-camera, SPECT, PET) detect and image the distribution of a radiopharmaceutical within the human body. The data collected by the detecting systems makes possible the emergence of a pathologic condition or function of the organs being imaged. In radiotherapy, specific tissues – organs uptake of the radiopharmaceuticals is carried out and the radiopharmaceuticals develop a lesion-targeted action to the ailing tissues. A Medical Physicist is involved in the nuclear medicine group which consists of the Nuclear Medicine Physicians, Technologists and Nurses. The Medical Physicist assesses and handles issues related to the use of open radioactive sources such as the radiopharmaceuticals and more generally the physical aspects of nuclear medicine applications.
The Medical Physicist exploits his/her knowledge about possible patient side – effects caused by radiation and the radiation exposure of the medical personnel and the patient’s relatives in order to develop accurate methods for the most effective dosage and safest in terms of radioprotection. He/she also has the required technical knowledge about the image and data analysis during the administration of the radioactive compounds.
Medical Physicist‘s role in Radiology
In the field of Radiology and Digital Imaging, a Medical Physicist gets involved with high-quality and high-precision machining technology such as Computed Tomography (CT) and Magnetic Resonance (MR) scanners, which can image the anatomy and functions of the human body. The high-tech machinery allows the Diagnostic Radiologists to detect anomalies, even if their size is very small or/and watch normal organ functions such as blood flow. The assurance of efficient and safe use of the high-tech machinery is the Medical Physicist’s role. Usually, the Medical Physicist participates in therapeutic procedures by applying image-guidance tools in e.g. brain neurosurgery or/and interventional cardiology. Medical Physics has made a major contribution in the medical imaging progress. Early detection of breast cancer represents tangible evidence. The image-guidance tools used for disease diagnosis, namely mammography, CT, MRI, PET and Ultrasound (US) have been developed, tested and standardized by Medical Physicists, working closely with Diagnostic Radiologists. Medical physicists were the first to develop standards and protocols which have now become federal law, resulting in improved image quality and reduced absorbed radiation dose to the patient during diagnostic tests.
Medical Physicist‘s role in Radioprotection
The radiation applications in medicine involve dangers for the irradiated patient’s body. For example, the radiation when used to kill cancer cells can cause severe damage to healthy cells as well. The activities of Medical Physicists in hospitals and more generally in healthcare facilities which aim for the safe use of radiation are described in one word: “RADIOPROTECTION”. Taking into consideration that the hospital’s Laboratory of Medical Physics and therefore the Medical Physicist (“Radioprotection Regulation”, 216/Β/6-3-2001) are nominated as legally and scientifically responsible for radioprotection issues, Radioprotection combines all the activities and procedures which ensure the effectiveness of radiotherapy (required dose for cancer tissue destruction) or diagnosis (required dose for accurate and clear imaging) and also the absorbed dose minimisation of the exposed healthy tissues. All these radioprotection activities and procedures are achieved with: ● the selection and regular checking of appropriate and high-tech irradiation device, ● the safe use of the radiology, nuclear medicine and/or radiotherapy units and checking the radiation exposure with appropriate radiation detectors-meters, ● the appropriate shielding design, ● the safe use and storage of radioactive materials and the safe disposal of the radioactive waste of the hospitals, ● the creation of prevention protocols, protocols for dealing with radiation accidents, and protocols promoting the neutralisation of contaminated areas by radiation, ● the supervision, provision of education and assistance to the employees and governing body members of organizations so that the radioprotection regulations etc. will constantly be respected and applied.
Research and Teaching
Many Medical Physicists are engaged in medical research, at Universities, Hospitals and Research Centers. Their achievements guaranteed improved radiotherapy treatments as well as better and more accurate diagnoses, from the era of Wilhelm Roentgen and Marie Curie to date.