Responsibilities of the Medical Physicist
It is the responsibility of medical physicists working in the Oncotherapy Department to ensure that all equipment, and especially equipment used for treatment of patients function according to specifications. New treatment techniques and computer procedures are also developed and verified before being implemented in co-operation with the personnel of the Oncotherapy Department.
The medical physicist in the Department of Oncotherapy is involved in maintaining and ensuring the correct functioning of equipment employed for the purpose of localising and treating cancer tumours in patients. This includes accurate dosimetry or the measurement of radiation beam intensity and the administration of treatment according to the prescription of the oncotherapist. Regular quality control in respect of equipment is therefore essential. During the localisation of tumours we use diagnostic imaging procedures such as computed tomography (CT) and X-ray simulation. Medical physicists are responsible for quality control of the imaging equipment to ensure that tumour size and density is determined correctly for accurate computer planning of the radiation treatment of patients.
The medical physicist accurately measure the radiation distribution obtained from linear accelerators during the acceptance of the machines. These measurements are transferred to a radiation treatment planning system that is computer based and the algorithms employed by the computer are also tested to ensure that the calculated simulations are valid.
The medical physicist is also responsible for the maintenance of computers and quality control in planning. The medical physicist is involved in the drawing up of specifications and the recommendation of purchase of equipment that will be the best for patient treatment. Following the purchase of such equipment, the medical physicist run well-specified acceptance tests before the equipment is accepted for implementation of patient treatment. After the equipment has been put into service, the medical physicist does daily quality control on the equipment to ensure that patients do indeed receive the correct prescribed radiation dose during treatment.
Radiation dose administered to individual patients during treatment is also checked regularly by means of thermoluminescent dosimeters. Doses are measured in cases where radiation sensitive organs, such as the eye, are located near the field of radiation, in order to ensure that such organs do not receive an unacceptably high dose.
The medical physicist is also responsible for implementing and execution of radiation safety control in the Oncotherapy Department to make sure that the radiation doses to personnel and general public are not higher than the permissible doses.