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Purpose/Objective(s): SBRT for cancers of the cervix may offer an alternative to brachytherapy for those patients who are not candidates for brachytherapy procedures. SBRT dose-fractionation schedules may be selected to approximate those of HDR in order to achieve similar radiobiologic dosing, while SBRT technique eliminates the need for applicator placement and sedation. Herein, we report health-related quality of life, toxicity and disease control outcomes of a prospective, phase II trial of SBRT for primary cervical cancers. Materials/Methods: Eligible patients included those with (1) pathologically confirmed cervical squamous cell carcinoma or adenocarcinoma; (2) FIGO stage IB, IIA or IIB disease; (3) technical or medical contraindication to brachytherapy; and (4) primary GTV < 125 cc following induction therapy. Induction therapy consisted of external beam radiotherapy (EBRT) to a minimum dose of 45.0 Gy encompassing primary tumor and regional pelvic lymphatics. All patients received weekly cisplatin-based chemotherapy concurrent with EBRT. SBRT boost treatment planning then followed, and GTV delineation was aided by co-registration of the boost planning CT set to a post-EBRT MRI. A boost dose of 40.0 Gy was prescribed to the primary tumor and delivered over a 10-day schedule of 5 fractions of 8.0 Gy each. Assessments included (1) disease response was determined pathologically by 3-month post-therapy biopsy and radiographically by biannual PET/CT imaging for 2 years; (2) acute and chronic toxicities were assessed using the National Cancer Institute's CTCAE v3 toxicity scales; and (3) quality-of-life was scored using FACT-G measurements. Results: Fifty-five patients with FIGO stage IB-IIB cervical cancer have been treated since June 2007 and have been followed for a median of 72.0 months (range, 60 e 132 months). Stage distribution was as follows: 6/55 FIGO stage IB1, 18/55 FIGO stage IB2, 3/55 FIGO stage IIA1, 6/55 FIGO stage IIA2 and 22/55 FIGO stage IIB. Post-SBRT biopsy at 3 months was negative for 52 of 55 patients, or 94.5%, for all patients. At 5 years, estimated local control by combined pathologic and radiographic (i.e., PET SUVmax < 2.5) criteria at the SBRT treatment site is 92.3% for all patients. No NCI CTCAE grade 3 or greater urinary or bowel toxicities have been observed to date. Urinary frequency was the most common grade 1 e 2 acute toxicity, observed for 43.2% of patients. Post-treatment FACT-G overall scores at 2 years were statistically superior compared to pre-treatment assessments and for the following domains: physical, emotional and functional wellbeing. Conclusion: At a minimum follow-up of 5 years, SBRT offers an effective and well-tolerated boost modality for selected FIGO stage IB-IIB cervix cancer patients otherwise contraindicated for brachytherapy. To our knowledge, this prospective phase 2 study reports the largest cohort of cervical cancer cases treated with curative intent using boost SBRT.

We have studied channeling effects in a Cesium Iodide (CsI) crystal that is similar in composition to the ones being used in a search for Weakly Interacting Massive Particles (WIMPs) dark matter candidates, and measured its energy-dependent quenching factor, the relative scintillation yield for electron and nuclear recoils. The experimental results are reproduced with a GEANT4 simulation that includes a model of the scintillation efficiency as a function of electronic stopping power. We present the measured and simulated quenching factors and the estimated effects of channeling. *

For the GBAR (Gravitational Behaviour of Antihydrogen at Rest) experiment at CERN's Antiproton Decelerator (AD) facility we have constructed a source of slow positrons, which uses a low-energy electron linear accelerator (linac). The driver linac produces electrons of 9 MeV kinetic energy that create positrons from bremsstrahlung-induced pair production. Staying below 10 MeV ensures no persistent radioactive activation in the target zone and that the radiation level outside the biological shield is safe for public access. An annealed tungsten-mesh assembly placed directly behind the target acts as a positron moderator. The system produces 5 × 10 7 slow positrons per second, a performance demonstrating that a low-energy electron linac is a superior choice over positron-emitting radioactive sources for high positron flux.

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