Toward Neuro-Oncologic Clinical Trials of High-Dose-Rate Synchrotron Microbeam Radiation Therapy: First Treatment of a Spontaneous Canine Brain Tumor.

PURPOSE: The high potential of microbeam radiation therapy (MRT) in improving tumor control while reducing side effects has been shown by numerous preclinical studies. MRT offers a widened therapeutic window by using the periodical spatial fractionation of synchrotron generated x-rays into an array of intense parallel microbeams. MRT now enters a clinical transfer phase. As proof of principle and cornerstone for the safe clinical transfer of MRT, we conducted a "first in dog" trial under clinical conditions. In this report, we evaluated whether a 3-dimensional conformal MRT can be safely delivered as exclusive radiosurgical treatment in animal patients METHODS AND MATERIALS: We irradiated a 17.5-kg French bulldog for a spontaneous brain tumor (glioma suspected on magnetic resonance imaging) with conformal high-dose-rate microbeam arrays (50-µm-wide microbeams, replicated with a pitch of 400 µm) of synchrotron-generated x-rays. The dose prescription adjusted a minimal cumulated valley dose of 2.8 Gy to the plnning target volume (PTV) (cinical target volume (CTV)+ 1 mm). Thus, each beam delivered 20 to 25 Gy to the target as peak doses, and ∼1 Gy as valley doses RESULTS: The treatment was successfully delivered. Clinical follow-up over 3 months showed a significant improvement of the dog's quality of life: the symptoms disappeared. Magnetic resonance imaging, performed 3 months after irradiation, revealed reduction in tumor size (-87.4%) and mass effect with normalization of the left lateral ventricle. CONCLUSIONS: To our knowledge, this neuro-oncologic veterinary trial is the first 3-dimensional conformal synchrotron x-ray MRT treatment of a spontaneous intracranial tumor in a large animal. It is an essential last step toward the clinical transfer of MRT in the near future to demonstrate the feasibility and safety of treating deep-seated tumors using synchrotron-generated microbeams.

Multiscale pink-beam microCT imaging at the ESRF-ID17 biomedical beamline.

Recent trends in hard X-ray micro-computed tomography (microCT) aim at increasing both spatial and temporal resolutions. These challenges require intense photon beams. Filtered synchrotron radiation beams, also referred to as `pink beams', which are emitted by wigglers or bending magnets, meet this need, owing to their broad energy range. In this work, the new microCT station installed at the biomedical beamline ID17 of the European Synchrotron is described and an overview of the preliminary results obtained for different biomedical-imaging applications is given. This new instrument expands the capabilities of the beamline towards sub-micrometre voxel size scale and simultaneous multi-resolution imaging. The current setup allows the acquisition of tomographic datasets more than one order of magnitude faster than with a monochromatic beam configuration.

The impact of the interview in pediatric residency selection.

OBJECTIVE: To better understand the impact of USMLE scores and interview scores on the National Resident Matching Program (NRMP) rank of applicants to the residency program at The Children's Hospital of Philadelphia. METHODOLOGY: We evaluated 935 applicants' files from 2000, 2001, and 2002. For each candidate, one interviewer had access to the full application, while the other interviewer was blinded to USMLE scores and grades. Interview scores were generated by both interviewers. Statistical analysis was performed to evaluate relationships between USMLE scores, interview scores, and NRMP rank list number. RESULTS: There were a wide range of USMLE scores among candidates who interviewed (range 181 to 269, 227.7 +/- 17.1, M +/- standard deviation). USMLE scores were weakly correlated to nonblinded interview scores (r = -0.17), final committee scores (r = -0.26), and NRMP ranking (r = -0.21): P < .0005. Blinded interviews did not correlate with USMLE scores. Both nonblinded and blinded interviews had stronger correlations with NRMP rank list number (r = 0.49, P < .0005 and r = 0.36, P < .0005, respectively). The nonblinded interview accounted for 20.6% of variance in the NRMP rank list order. CONCLUSIONS: Interview scores were the most important variable for candidate ranking on the NRMP list. Furthermore, when interviewers had access to board scores, there was a modest correlation to performance on the USMLE. While interviews may reflect a candidate's personality, they may not effectively measure desired characteristics when access to academic markers is unrestricted. We suggest incorporating blinded interviews into the selection process to give candidates a better opportunity to display communication skills, emotional stability, and "fit" for the program.