Links & GlossaryNuclear Med. Glossary S-ZThe Nuclear Medicine Glossary by Richard Zimmerman, IBA Letters S to ZScanner :an imaging tool using X- or γ-rays that provide virtual sectioning (scans) of the area being analyzed. Scintigraphy :method of imaging based on recording γ or β+ radiation emitted by a substance injected into the patient which concentrates in a particular organ or tissue (heart, thyroid, bones, etc.). Sealed source :a radioactive substance placed in a sealed container, irradiating but not contaminating. The implants used in internal radiotherapy are sealed sources. Side-effects or undesirable effects :disturbance to the state of health of any sort not linked to the principal illness, but more often to the treatment itself. For example: headaches, gastric problems, nausea and vomiting, hair loss, and changes in blood count as a result of, or in parallel to, chemotherapy. Sievert(Sv) :unit of equivalent dose, corresponding to a corrected dose of the ionizing effect of the radiation (for X, β+, and γ radiation, 1 Sv = 1 Gy). Previously the Rem was used, with one Sievert equivalent to 100 Rems. Source :origin of radiation. By extension, the radioactive substance itself. Specific activity :radioactive activity value comparing the activity of the radionuclide with the total mass of the element present. When the radioisotope is present in its pure form, even in an extremely dilute solution, we talk about a carrier-free radioisotope solution. It is expressed in becquerels per mass unit. Specific concentration :value that determines the degree of radioactive substance per volume unit. It is expressed in Becquerels per volume unit. Specific/specificity :describes molecules that only target a single type of cell or receptor. SPECT :single-photon emission computed tomography. The imaging modality based on the measurement of γ-ray emission. Targeted or vectorized radiotherapy :a more general term including metabolic radiotherapy. This nuclear medicine technique consists in treating a specific tissue of the organism with ionizing radiation, itself originating from the concentration of a substance which participates in a biological mechanism (the vector) and to which a suitable radionuclide is grafted. Tomography :radiography providing a clear image of a single cross-section. Vector :chemical substance which has the property of being recognized by certain macromolecules present in tissue (receptor, enzyme, etc.) and on which is grafted another toxic or radioactive substance, for therapeutic or diagnostic purposes. X-rays :invisible short wave light radiation produced either directly by a radioactive substance or indirectly by excitation of atoms, and capable of traversing material |