In physics, attenuation (in some contexts also called extinction) is the gradual loss in intensity of any kind of flux through a medium. For instance, sunlight is attenuated by dark glasses, X-rays are attenuated by lead, and light and sound are attenuated by water.n engineering, attenuation is usually measured in units of decibels per unit length of medium (dB/cm, dB/km, etc.) and is represented by the attenuation coefficient of the medium in question.
PET Scan (Skull to Mid-Thigh) Cost and Procedure Information. Positron Emission Tomography, also called a PET scan, is a diagnostic examination that involves the acquisition of physiologic images based on the detection of radiation from the emission of positrons. Positrons are tiny particles emitted from a radioactive substance administered to the patient.
There is abnormal increased uptake of In-111 white blood cells in the right femur (arrow) and thigh, not matched by a similar area on the Tc-99m bone marrow scan indicating active infection in this patient. 1  Positron emission tomography (PET) uses 18F-fluorodeoxyglucose (FDG) as a scanning agent.