Roger K. Rice

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PURPOSE To present the clinical implementation of a new HDR device for partial breast irradiation, the Strut-Adjusted Volume Implant (SAVI), at the University of California, San Diego. METHODS AND MATERIALS The SAVI device has multiple peripheral struts that can be differentially loaded with the HDR source. Planning criteria used for evaluation of the(More)
A mathematical model was used to estimate the cost-effectiveness of colorectal cancer screening strategies for people who are at high risk because of a first-degree relative with colorectal cancer. The model uses indirect evidence about such factors as cancer incidence, sensitivity and specificity of different tests, and treatment effectiveness. The(More)
A well defined set of clinically relevant reference measurements for photon dose calculations in the presence of the lung have been provided. These benchmark data were mainly obtained in low-density (rho = 0.31 gcm-3) lunglike material as well as in waterlike plastic for 4 and 15 MV X-ray beams. Some additional measurements were performed with materials(More)
OBJECTIVES To report our experience using Image-Guided Radiation Therapy (IGRT) in patients undergoing post-prostatectomy irradiation. METHODS Twenty-six patients were treated with radiotherapy following radical prostatectomy using Intensity Modulated Radiation Therapy (IMRT). Prostate bed localization was done using image guidance to align surgical clips(More)
BACKGROUND AND PURPOSE In this study, we investigated IMRT QA using Statistical Process Control for the purpose of comparing the processes of patient-specific measurements and the corresponding independent computer calculations. MATERIALS AND METHODS Point dose data from the treatment planning system (TPS), independent computer calculations, and physical(More)
Cone beam CT (CBCT) has been widely used for patient setup in image-guided radiation therapy (IGRT). Radiation dose from CBCT scans has become a clinical concern. The purposes of this study are (1) to commission a graphics processing unit (GPU)-based Monte Carlo (MC) dose calculation package gCTD for Varian On-Board Imaging (OBI) system and test the(More)
The optically-guided frameless system (OFLS) has been used in our clinic for intracranial stereotactic radiosurgery (SRS) since 2006, as it is especially effective in IMRT-based radiosurgery (IMRS), which allows treating multiple brain lesions simultaneously using single isocenter approach. This study reports our retrospective analysis of patient setup(More)
We have employed a frameless localization system for intracranial radiosurgery, utilizing a custom biteblock with fiducial markers and an infra-red camera for set-up and monitoring patient position. For multiple brain metastases or large irregular lesions, we use a single-isocenter intensity-modulated approach. We report our quality assurance measurements(More)
The purpose of this study is two-fold: first is to investigate the process of IMRT QA using control charts and second is to compare control chart limits to limits calculated using the standard deviation (sigma). Head and neck and prostate IMRT QA cases from seven institutions in both academic and community settings are considered. The percent difference(More)
Dose distributions produced by small circular beams of 6 MV x-rays have been measured using ionisation chambers of small active volume. Specific quantities measured include tissue maximum ratios (TMR), total scatter correction factors (St), collimator scatter correction factors (Sc) and off-axis ratios (OAR). Field sizes ranged from 12.5 to 30 mm diameter,(More)