Editing Radiology (section)

=== Nuclear medicine ===
{{main|Nuclear medicine}}

Nuclear medicine imaging involves the administration into the patient of radiopharmaceuticals consisting of substances with affinity for certain body tissues labeled with radioactive tracer. The most commonly used tracers are technetium-99m, iodine-123, iodine-131, gallium-67, indium-111, thallium-201 and [[fludeoxyglucose (18F)|fludeoxyglucose (<sup>18</sup>F)]] (<sup>18</sup>F-FDG). The [[heart]], [[lung]]s, [[thyroid]], [[liver]], [[brain]], [[gallbladder]], and bones are commonly evaluated for particular conditions using these techniques. While [[anatomy|anatomical]] detail is limited in these studies, nuclear medicine is useful in displaying [[physiology|physiological]] function. The excretory function of the kidneys, iodine-concentrating ability of the thyroid, blood flow to heart muscle, etc. can be measured. The principal imaging devices are the [[gamma camera]] and the PET Scanner, which detect the radiation emitted by the tracer in the body and display it as an image. With computer processing, the information can be displayed as axial, coronal and sagittal images (single-photon emission computed tomography - SPECT or Positron-emission tomography - PET). In the most modern devices, nuclear medicine images can be fused with a CT scan taken quasisimultaneously, so the [[physiology|physiological]] information can be overlaid or coregistered with the anatomical structures to improve diagnostic accuracy.{{citation needed|date=May 2024}}

[[Positron emission tomography]] (PET) scanning deals with positrons instead of gamma rays detected by [[gamma camera]]s. The positrons annihilate to produce two opposite traveling gamma rays to be detected coincidentally, thus improving resolution. In PET scanning, a radioactive, biologically active substance, most often <sup>18</sup>F-FDG, is injected into a patient and the radiation emitted by the patient is detected to produce multiplanar images of the body. Metabolically more active tissues, such as cancer, concentrate the active substance more than normal tissues. PET images can be combined (or "fused") with anatomic (CT) imaging, to more accurately localize PET findings and thereby improve diagnostic accuracy.{{citation needed|date=May 2024}}

The fusion technology has gone further to combine PET and MRI similar to PET and CT. [[PET/MRI]] fusion, largely practiced in academic and research settings, could potentially play a crucial role in fine detail of brain imaging, breast cancer screening, and small joint imaging of the foot. The technology recently blossomed after passing the technical hurdle of altered positron movement in strong magnetic field thus affecting the resolution of PET images and attenuation correction.{{citation needed|date=May 2024}}