Application of a radiophotoluminescent glass dosimeter to nonreference condition dosimetry in the postal dose audit system.

Purpose: The purpose of this study was to obtain a set of correction factors of the radiophotoluminescent glass dosimeter (RGD) output for field size changes and wedge insertions.

Methods: Several linear accelerators were used for irradiation of the RGDs. The field sizes were changed from 5 × 5 cm to 25 × 25 cm for 4, 6, 10, and 15 MV x-ray beams.

Detector to detector corrections: a comprehensive experimental study of detector specific correction factors for beam output measurements for small radiotherapy beams.

Purpose: The aim of the present study is to provide a comprehensive set of detector specific correction factors for beam output measurements for small beams, for a wide range of real time and passive detectors. The detector specific correction factors determined in this study may be potentially useful as a reference data set for small beam dosimetry measurements.

Methods: Dose response of passive and real time detectors was investigated for small field sizes shaped with a micromultileaf collimator ranging from 0.

Positional dependence of the CT number with use of a cone-beam CT scanner for an electron density phantom in particle beam therapy.

We evaluated the CT number accuracy in determining a CT calibration method for treatment planning by use of a 256 multi-slice CT (MSCT) scanner. An electron density phantom, which extends full length in the longitudinal direction, was scanned by the 256 MSCT scanner in a single rotation. We inserted four types of samples (air, 100 % ethanol, 40 wt% aqueous K(2)HPO(4), and water) into the phantom.

Development of a multi-layer ionization chamber for heavy-ion radiotherapy.

A multi-layer ionization chamber (MLIC) which consists of a stack of parallel plate-type ionization chambers in which the parallel configuration is in the depth direction was developed at the National Institute of Radiological Science (NIRS) and has been used as a field dosimeter for MU calibration since 2002. Although the MLIC can measure depth dose distributions at one time, a correction is needed to obtain an accurate dose at the center of the spread-out Bragg peak (SOBP) in a water phantom. We attributed the observed difference between the correct dose at the center of the SOBP and the measured dose to the lack of water equivalence of the MLIC.

FcgammaRIIB deficiency with Fas mutation is sufficient for the development of systemic autoimmune disease.

MRL.Fas(lpr/lpr) mice, a model for systemic lupus erythematosus (SLE) and arthritis in humans, have a Fas mutation that results in spontaneous development of systemic autoimmune diseases and a short life span. Half of them die by 5-6 months of age due to massive progression of systemic autoimmune diseases, such as lupus nephritis.