CPT® Code 78018

The CPT® Code 78018 refers to a nuclear medicine imaging study specifically designed to assess the presence and extent of metastatic disease related to thyroid carcinoma throughout the entire body. This procedure involves the administration of radioactive iodine isotopes, commonly known as radioactive tracers, which can be given either orally in liquid or capsule form or intravenously. The method of administration dictates the timing of the imaging procedure; if the tracer is taken orally, imaging occurs several hours to 24 hours later, allowing sufficient time for the tracer to circulate and localize in areas of potential metastasis. Conversely, if the tracer is administered intravenously, imaging is conducted approximately 30 minutes post-administration, as the tracer is expected to be more rapidly distributed throughout the body. During the imaging process, the radioactive isotopes emit gamma rays, which are captured by a gamma camera. This camera, in conjunction with computer processing, generates images that are displayed on a computer screen for analysis. The procedure is comprehensive, as it encompasses a whole-body survey, unlike related codes such as 78015, which focuses on limited regions like the neck and chest. In the whole-body scan, the patient is positioned supine on the examination table for the initial scan of the front body, followed by a prone position to scan the back. The resulting images provide critical information regarding the distribution of metastatic sites, which is essential for the physician's evaluation and subsequent reporting of findings.