Nuclear Medicine

Nuclear Medicine (NM) is the diagnosis and treatment of diseases (including cancer) with the use of radiopharmaceuticals. This is a combination of a radioactive tracer and a pharmaceutical compound. Radiopharmaceuticals are ingested by or injected intravenously inside the patient. The pharmaceutical portion of the compound is required to transport the radioactive tracer to the area of interest within a patient. The radioactive tracer is required to locate the pharmaceutical. Radiation emitted is recorded via a gamma camera or a PET scanner, where static (photos) or dynamic images (videos) are acquired over a short period of time. Unlike the majority of other modalities (such as CT, MRI etc.) which target patient anatomy, examinations in NM give physiological information of the patient. Common examinations include myocardial perfusion scanning, bone scans, renal cortical scintigraphy, renograms and cancer diagnosis and staging with FDG.

The medical physicist in this area ensures safe, effective and optimal use of radioactive sources in a hospital setting to diagnose and treat malignancies. Apart from sources, medical physicists are also responsible for the acceptance and commissioning of a number of systems such as SPECT-CT and PET-CT systems, contamination and dose rate monitors, dose calibrators and well counters.

In nuclear medicine, most clinical examinations require image processing to provide a combination of reliable qualitative and quantitative information. The medical physicists work with computer engineers to develop several image processing libraries, for example to construct 3D images from the 2D images that are typically acquired in a Nuclear Medicine Unit. The medical physicist then further develops the necessary quality assurance protocols to ensure that the 3D images are of diagnostic quality through collaboration with the nuclear medicine physicians.

During nuclear medicine therapeutic procedures, such as liver therapy with Y-90 sources, medical physicists calculate the optimal amount of radioactive tracer that should be injected in order to kill a tumour while minimizing radiation-induced damage to healthy tissue.

Medical physicists in this area continually monitor and advise on the precautions necessary to keep members of staff and the public safe. This includes the preparation of risk assessments as well as any required radiation barrier calculations. Physicists work closely with the radiation protection expert to achieve this goal.