Commissioning and initial experience with the first clinical gantry-mounted proton therapy system.

The purpose of this study is to describe the comprehensive commissioning process and initial clinical experience of the Mevion S250 proton therapy system, a gantry-mounted, single-room proton therapy platform clinically implemented in the S. Lee Kling Proton Therapy Center at Barnes-Jewish Hospital in St. Louis, MO, USA. The Mevion S250 system integrates a compact synchrocyclotron with a C-inner gantry, an image guidance system and a 6D robotic couch into a beam delivery platform. We present our commissioning process and initial clinical experience, including i) CT calibration; ii) beam data acquisition and machine characteristics; iii) dosimetric commissioning of the treatment planning system; iv) validation through the Imaging and Radiation Oncology Core credentialing process, including irradiations on the spine, prostate, brain, and lung phantoms; v) evaluation of localization accuracy of the image guidance system; and vi) initial clinical experience. Clinically, the system operates well and has provided an excellent platform for the treatment of diseases with protons.

Salvage radioembolization of liver-dominant metastases with a resin-based microsphere: initial outcomes.

PURPOSE: The use of radioembolization of hepatic metastases with yttrium-90 ((90)Y) microspheres is increasing. The present report describes the outcomes in a cohort of patients with metastatic liver tumors treated with a resin-based microsphere agent. MATERIALS AND METHODS: Thirty patients with colon (n = 13), breast (n = 7), and other primary cancers (n = 10) were treated after the failure of first- and second-line therapy. Overall survival (OS), time to progression (TTP), and time to treatment failure (TTTF) were calculated from the first treatment. Response was measured according to Response Evaluation Criteria In Solid Tumors at interval follow-up imaging. RESULTS: Thirty patients underwent 56 infusions of (90)Y, and 18 remained alive at the end of the study. Fourteen patients (47%) had a partial response or stable disease. OS (604 vs 251 days), TTP (223 vs 87 days), and TTTF (363 vs 87 days) were all significantly longer for patients who had a partial response or stable disease (P < .05). Median OS, TTP, and TTTF for patients with colorectal carcinoma were 357, 112, and 107 days, respectively, versus 638, 118, and 363 days in patients with other metastatic sources. Median survival was not reached for patients with breast carcinoma, and the TTP and TTTF were each 282 days. One patient (3%) experienced grade 3 toxicity (gastrointestinal ulceration). CONCLUSIONS: (90)Y microsphere therapy produced promising survival rates compared with systemic salvage options, with minimal toxicity.

Injectable Hydrogels for Localized Chemotherapy and Radiotherapy in Brain Tumors.

Overall survival of patients with newly diagnosed glioblastoma (GBM) remains dismal at 16 months with state-of-the-art treatment that includes surgical resection, radiation, and chemotherapy. GBM tumors are highly heterogeneous, and mechanisms for overcoming tumor resistance have not yet fully been elucidated. An injectable chitosan hydrogel capable of releasing chemotherapy (temozolomide [TMZ]) while retaining radioactive isotopes agents (iodine, [131I]) was used as a vehicle for localized radiation and chemotherapy, within the surgical cavity. Release from hydrogels loaded with TMZ or 131I was characterized in vitro and in vivo and their efficacy on tumor progression and survival on GBM tumors was also measured. The in vitro release of 131I was negligible over 42 days, whereas the TMZ was completely released over the first 48 h. 131I was completely retained in the tumor bed with negligible distribution in other tissues and that when delivered locally, the chemotherapy accumulated in the tumor at 10-fold higher concentrations than when delivered systemically. We found that the tumors were significantly decreased, and survival was improved in both treatment groups compared to the control group. Novel injectable chemo-radio-hydrogel implants may potentially improve the local control and overall outcome of aggressive, poor prognosis brain tumors.