On the development of an interstitial radiation protocol for a multicenter consortium. Experience with permanent low-dose rate and temporary high-dose rate 125I implants in 'failed' and 'newly diagnosed' glioblastoma patients: quality assurance methodology and a possible future adjuvant for therapeutic enhancement.

Three interstitial implant trial groups (one permanent low-dose rate 125I and two temporary high-dose rate 125I implants) in glioblastoma patients ('newly diagnosed' and 'failed') were compared to non-randomized similar control groups for efficacy. The results formed the basis for the BTCG 87-01 national implant trial. The 'pilot' trial demonstrated: 1) the effectiveness of a temporary high-dose rate 125I implant in 'failed' and 'newly diagnosed' patients; 2) the ability of a multicenter consortium to adhere to a standard protocol; 3) a methodology to insure quality assurance; and 4) the possibility of the future adjuvant application of hyperthermia using a single catheter system.

On a method of dosimetry planning and implantation of 125I for interstitial irradiation of malignant gliomas.

Utilizing a treatment concept geared to the cell cycle of the glioma, a CT determined tumor volume and boundaries, 125I dosimetry data and a reference probe template system, it is now feasible to produce a volume implant of an intracranial mass based on prospective planning with accurate postimplant correspondence. The cell cycle oriented treatment plan is felt perhaps to be more beneficial in the treatment of the highly malignant glioblastoma, considering its wide range of cell cycle times, large irregular volumes and large dormant segment, than would be a similar isotope source delivering a high-dose rate, but short-term course irradiation. Seeds are contained within Lexan tubes, thereby allowing accurate assessment of postoperative dosimetry planning, negating seed migration and possible 'cold spots' within a volume implant as would be noted with unrestrained seeds. The implant described in this communication is designed to remain in place for approximately 20 months, a period of time well beyond the life expectancy of any group of failed glioma patients. Although ultimately the system may prove most beneficial in newly diagnosed glioblastomas, the current trial in patients having previously undergone 5-6000 rads of external beam therapy is not considered hazardous to surrounding brain.