Medical physicists are scientists employed across many different fields of healthcare, contributing to the diagnosis and treatment of disease.
Physicists working in nuclear medicine specialise in the use of radioactive materials, principally for diagnostic purposes but some treatments are administered in the department.
Radioactive materials emit radiation, but we can use gamma, beta, and alpha radiation to help care for patients. Medical physicists are the experts in radiation safety and carefully tune the amount of radioactive material administered to make sure that patients have the best outcome with the lowest possible risk.
Balancing the benefits versus the risk is not always an easy task! Medical physicists use the most up-to-date scientific research to bring innovation into the hospital. Despite the important work they do, a patient may never see a medical physicist in nuclear medicine.
Technologists are another group of people with important roles and are a little bit like a radiographer. They will perform many of the practical tasks related to a patient’s appointment in nuclear medicine and are experts at performing scans and the safe administration of pharmaceuticals. Skilled laboratory technicians, they manufacture and dispense our radioactive pharmaceuticals to the highest clinical standards.
The radioactive material must be attached to something that takes delivers it to the target area. This is the job of the pharmaceutical, which has a molecular form that allows it to act like a homing device. For example, a radioactive material may be attached to a pharmaceutical that specifically binds to a particular particular disease site. Once in place, the radioactive material enables us to pinpoint its location in the body.
The majority of patient appointments in nuclear medicine are for diagnostic imaging. Travelling in straight lines, the penetrating gamma radiation emitted from the radioactive material easily escapes the patient’s body. We can detect this using a gamma camera. Within the gamma camera, the gamma ray is converted into a shower of visible light, which in turn is converted into an electrical signal. The computer then traces back the origin of this signal to produce an image. Gamma rays emitted from the location of the disease area allows the gamma camera to localise the position of the radioisotope within the body.
Nuclear medicine therapies work along a similar principle. The radioactive material homes into the target site, carried by the pharmaceutical. Instead of gamma rays, we use radioactive materials that emit beta or alpha radiation. These types of emissions are much more damaging to human tissue but only travel a couple of millimetres, allowing us to treat disease by selectively destroying the tissue in a defined area but saving healthy tissue from the effects of radiation.
In addition it is possible to subsequently locate the areas that have taken up the radiation within the body using the gamma camera.
Whatever type of nuclear medicine appointment the patient attends in nuclear medicine, their safety and comfort is paramount.