fiducial marker
Pronunciation: fi-DOO-shal MAR-ker
Radiopaque objects implanted near tumors to enable precise target localization and motion tracking during radiation therapy.
Full Definition
Fiducial markers are small, radiopaque objects (typically gold seeds, coils, or carbon markers) surgically implanted in or near tumor sites to serve as reference points for image-guided radiation therapy. These markers are clearly visible on both planning CT scans and daily imaging, allowing radiation therapists to precisely align the patient and account for organ motion or setup variations. Fiducial markers are particularly valuable for treating mobile organs like the prostate, liver, and lung, where internal anatomy can shift between fractions. The markers enable real-time tracking during treatment delivery and facilitate accurate dose delivery to moving targets while minimizing radiation exposure to healthy tissues.
Usage
Usage note: From Latin 'fiducia' meaning trust; essential for image-guided radiotherapy protocols.
In Context
- "Three gold fiducial markers were implanted transperineally to enable prostate motion tracking." — Procedure note
- "Daily cone-beam CT imaging verified fiducial marker positions before treatment delivery." — Treatment verification report