Interstitial radiation therapy for hepatic metastases: sonographic guidance for applicator placement

A new technique is reported for the treatment of hepatic metastases using sonography-directed percutaneous placement of a 14-gauge needle applicator and a high-intensity "remote afterloading" iridium-192 (Ir-192) source for interstitial radiation therapy. The results with six patients show that the procedure is easily performed, patient tolerance is good, and there is minimal disruption of the patient's lifestyle. Hospitalizations have been less than 24 hr. Partial response or stable disease in the liver was observed in all six patients. Tumoricidal doses up to 5000 rad (cGy) in a single treatment with durations from 7 to 41 min were achieved in small volumes (less than 25 cm3) with no clinically significant toxicity on follow-up evaluations from 2-6 months. The technique appears to ablate discrete metastatic tumor deposits in the liver.