Permanent radioactive iodine seed implants following radical resection in recurrent human malignant high grade astrocytomas
Radical brain tumor resection coupled with iodine seed (I-125) implantation was performed 9 times on 8 patients with recurrent malignant cerebral gliomas. Sodium fluorescein dye was administered intravenously at the time of craniotomy as a ‘tumor marker’. Fluorescent-stained tissues were identified by mercury arc lamp illumination and subsequently removed using an ultrasonic surgical tissue aspirator. I-125 seeds were placed intraoperatively at nonfluorescent tumor margins. The seed number and activity were determined graphically from a computer model for ‘shell’ irradiation. A calculated tumor dose of 25–30,000 cGy (rads) (complete decay) was delivered.
The first 6 patients were treated from December 1982 through November 1983 with follow-up examination in 100% of patients. The first 3 patients had pre- and postoperative Karnofsky ratings of 50/70, 40/40 and 60/90 and survived 9, 1, and 5 months, respectively, following surgery and seed implantation. The last 3 patients in this group had pre- and postoperative Karnofsky ratings of 100/100, 80/80, and 90/90, and are living as well, 16, 14, and 12 months, respectively, following radioactive seed implants. All four of the longterm surviving patients developed a delayed-onset of cerebral edema and developed cyst formation in the site of tumor resection which is clinically significant in three.
Seven of eight patients underwent aggressive surgical removal of ‘all’ fluorescein tussues to the extent that their postoperative CT scans showed disappearance of contrast dye enhancing images. Both therapeutic modalities, performed together at cranial surgery, offer a simple, direct, and more precise approach for treating brain malignancies.
Key wordsblood-brain barrier brachytherapy brain neoplasms fluorescein tracer agent interstitial irradiation radiation therapy
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