We assessed the accuracy of a prototype radiation detector with a built in CMOS amplifier for use in dosimetry for high dose rate brachytherapy. The detectors were fabricated on two substrates of epitaxial high resistivity silicon. The radiation detection performance of prototypes has been tested by ion beam induced charge (IBIC) microscopy using a 5.5 MeV alpha particle microbeam. We also carried out the HDR Ir-192 radiation source tracking at different depths and angular dose dependence in a water equivalent phantom. The detectors show sensitivities spanning from (5.8 ± 0.021) × 10−8 to (3.6 ± 0.14) × 10−8 nC Gy−1 mCi−1 mm−2. The depth variation of the dose is within 5% with that calculated by TG-43. Higher discrepancies are recorded for 2 mm and 7 mm depths due to the scattering of secondary particles and the perturbation of the radiation field induced in the ceramic/golden package. Dwell positions and dwell time are reconstructed within ±1 mm and 20 ms, respectively.
Patients with metastatic brain tumors are among the most desperate of patients for at least a modestly effective treatment let alone a cure, and GT Medical Technologies Inc., of Tempe, Ariz., reported the interim findings from a study of 48 patients suffering from a total of 51 brain metastases. Four-month data from this study demonstrate that implant of the Gammatile device is safe as demonstrated by the lack of adverse events, and these results combined with other data suggest that this device can offer this patient population real hope of surviving one of the deadliest series of afflictions known to humankind.