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Practical InformationThe ExamNuclear Medicine examination procedures for diagnosis purposes: where and how they are carried out, which techniques are used and what they entail, how long they last, what are the advantages of such exams. by Eric Laurent, MD, CHIREC Group, Belgium Head of the NM Department, Edith Cavell Clinique, Brussels. These diagnostic exams take place in the Nuclear Medicine Department. They are neither dangerous nor painful. The process begins with the intravenous injection of a tracer marked with a radioactive isotope, specifically targeting the organ to be observed. Concerning certain digestive exams, the tracer will be administered via the mouth in the form of a drink or a meal. No pain and no after effects are expected, and allergic reactions are extremely rare. Some injections will be filmed in order to study the dynamic distribution characteristics. The isotope emits a feeble radiation quantity, yet consequent enough to form an image under the camera detectors. The scintigraphy-delivered radiation does not exceed (and is very often inferior) to that of a CT Scan.
The required time for tracer fixation in the observed organ can vary. As a result, the time gap between the injection and camera procedure can last from a few minutes to a few hours. This time-period will be given to you when you fix an appointment. Camera image acquisitions last from 15 to 45 minutes, depending on the type of exam and the area to be explored. The process takes place either in a lying down position, or standing in front of the detector. To obtain the best possible images, the camera will move as close to your body as possible without ever touching you. You will be alone in the room, and will be asked to remain still and silent during the exam. Scintigraphy cameras cause less claustrophobia problems than MRIs and CT Scans. The exam is silent and is permanently monitored by a professional who can stop the process at any time if necessary. Sometimes, a scintigraphy acquisition is coupled to a CT Scan, carried out at the same time for increased diagnosis precision. This is systematically the case with the PET-CT. |
The isotope most often used for diagnosis purposes is Technetium 99m (99mTc). Its half-life is short (6 hours), meaning that it soon loses its radioactive properties. The quality and quantity of the product injected follows strict norms, and is controlled.