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Purpose: A novel 32P brachytherapy source has been in use at our institution intraoperatively for temporary radiation therapy of the spinal dura and other localized tumors. We describe the dosimetry and clinical implementation of the source. Methods and Materials: Dosimetric evaluation for the source was done with a complete set of MCNP5 Monte Carlo calculations preceding clinical implementation. In addition, the depth dose curve and dose rate were measured by use of an electron field diode to verify the Monte Carlo calculations. Calibration procedures using the diode in a custom-designed phantom to provide an absolute dose calibration and to check dose uniformity across the source area for each source before treatment were established. Results: Good agreement was established between the Monte Carlo calculations and diode measurements. Quality assurance measurements results are provided for about 100 sources used to date. Clinical source calibrations were usually within 10% of manufacturer specifications. Procedures for safe handling of the source are described. Discussion: Clinical considerations for using the source are discussed. [ABSTRACT FROM AUTHOR]

: PurposeAfter vertebral or paravertebral tumor resection, tumor cells may remain on the dura. Because a tumoricidal dose is difficult to achieve using external beam radiotherapy without exceeding the spinal cord tolerance, we developed intraoperative applicators to deliver additional dose to the dura.: Methods and materialsEight patients with vertebral or paravertebral tumor underwent conformal external beam radiotherapy, tumor resection, and intraoperative radiotherapy to the dura involved by tumor. At surgery, vertebra, soft tissue, and epidural tumor were resected. A radioactive applicator plaque was placed on the dura to deliver 7.5–15 Gy, and then removed. Vertebral reconstruction and stabilization was completed. Chemotherapy was administered for large, high-grade sarcomas.: ResultsWe progressed through three plaque designs, initially 192Ir, subsequently liquid 90Y, and finally 90Y foil in a semicylindrical polycarbonate plaque, in the treatment of 8 patients. The low-energy 90Y β-emissions provided a more attractive depth dose profile than that achievable with iridium and gave negligible staff radiation exposure. The 90Y depth dose measured 29% at 2 mm and 9% at 4 mm from the surface of the foil plaque, with acceptable surface dose homogeneity. The average surface dose rate ranged from 18.7 to 47.6 cGy/min for the iridium plaques and 45.2 to 187.5 cGy/min for the 90Y plaques. The treatments have been without acute or late neurologic complications. The disease of 6 of 8 patients was locally controlled at median potential follow-up of 24 months.: ConclusionsThe 90Y foil applicator is technically elegant, easy to use, and superior to the earlier models. It has been incorporated into a protocol for spinal tumor treatment. [Copyright &y& Elsevier]