Thyroid uptake of 125iodine after prostate permanent brachytherapy

To decrease the seed migration rate after 125I prostate brachytherapy and improve the quality of implants to our knowledge we report for the first time the detection of thyroid uptake, possibly from a damaged seed, in a patient after 125I implantation.

Seed migration detection is routinely offered to our patients at the post-evaluation visit. A seed migration detector and comprehensive investigation procedure have been developed for the task. Chest radiographs are ordered to document the location of the detected seed. A fluoroscopic study may be performed if intracardiac radioactivity is detected.

Since November 2001, 246 patients have been studied for seed migration. A total of 23,184 125I seeds were implanted, of which 75 were lost through the urethra and 25 migrated to the thorax. In the routine survey of a patient on February 13, 2003 radioactivity in the chest-neck region was sensed. Repeat radiographs and fluoroscopic examinations were negative for seed migration. Using a gamma camera butterfly-shaped uptake was noted in the thyroid region. The energy peak of the uptake matched the spectrum of the 125I source. The patient denied any intake of other iodine medication. The results suggested possible 125I leakage from at least 1 seed implanted in the prostatic region.

Improved control of seed migration has been achieved. The detection of thyroid uptake is reported. Detection techniques and subsequent actions are described.