Purpose: To describe a method and evaluate the efficacy of using a p-type silicon diode as an alternative to thermoluminescent dosimeters for verifying the accuracy of total marrow irradiation setups and calculations.
Methods And Materials: A calibration factor has been measured for a 6 MV photon beam incident horizontally onto a polystyrene phantom inside an in-house built total marrow irradiation stand. Signal responses due to positioning and orientation of the diode with respect to the source were compared to a 0.
Twenty patients with inoperable arteriovenous malformations (AVMs) of the brain were treated with neutron radiosurgery. A 50 MeV cyclotron was used to deliver 9 Gy in a single fraction through 7 to 14 isocentric portals. The size and shape of the portals were customized to each treatment site.
View Article and Find Full Text PDFA technique employing single fraction neutron radiosurgery for treatment of intracranial vascular malformations has been developed at the University of Washington and is described in this report. The natural history of arteriovenous malformations of the brain is briefly reviewed, along with currently available therapeutic methods for treatment of these lesions. The characteristics of the neutron beam used for radiosurgery are described, along with methods for patient immobilization, radiation treatment planning, dosimetry, and delivery of treatment using this technique.
View Article and Find Full Text PDFDosimetry intercomparisons have been performed between the Clatterbridge high-energy neutron facility and the following institutions, all employing beams with similar neutron energies: Université Catholique de Louvain, Belgium; University of Washington, Seattle, USA; MD Anderson Hospital, Houston, USA; and Fermi National Accelerator Laboratory, Batavia, USA. The purpose of the intercomparison was to provide a basis for the exchange of dose-response data and to facilitate the involvement of Clatterbridge in collaborative clinical trials. Tissue-equivalent ionization chambers were used by the participants in each intercomparison to compare measurements of total (neutron plus gamma) absorbed dose in the host institution's neutron beam, following calibration of the chambers in a reference photon beam.
View Article and Find Full Text PDFThirty-two patients with inoperable, recurrent, or gross residual malignant salivary gland tumors received fast neutron radiotherapy at the University of Washington. Eleven patients were treated with low energy neutrons alone, four received a combined photon-low energy neutron treatment regimen ("mixed beam"), and 17 were treated with high energy neutrons alone. Patients treated for microscopic residual tumor after a surgical resection were excluded from this study.
View Article and Find Full Text PDF