Measurement of dosimetric parameters for the Alpha-Omega high-dose-rate Iridium-192 source.

Thermoluminescent (TLD) measurements of dose-rate constant, anisotropy function, and radial dose function are reported for the Alpha-Omega high dose rate (HDR) Iridium-192 ((192)Ir) source, which has been available since 1998 for use in the MicroSelectron HDR afterloader manufactured by the Nucletron Corporation. Measurement results are compared with published or available Monte Carlo calculations for both sources. They are found in good agreement, and, within experimental accuracy, no difference is seen in the dosimetric parameters of both sources.

Changing face and different countenances of prostate cancer: racial and geographic differences in prostate-specific antigen (PSA), stage, and grade trends in the PSA era.

The purpose of this investigation was to examine changes in pretreatment prostate-specific antigen (PSA), stage, and grade over the past decade as a function of race and geographic region. A multiinstitutional database representing 6,790 patients (1,417 African-American, 5,373 white) diagnosed with nonmetastatic prostate cancer between 1988 and 1997 was constructed. PSA, stage, and grade data were tabulated by calendar year and region, and time trend analyses based on race and region were performed.

Determination of the tissue attenuation factor along two major axes of a high dose rate (HDR) 192Ir source.

Quantitative information on photon scattering around brachytherapy sources is needed to develop dose calculation formalisms capable of predicting dosimetric parameters with minimal empiricism. Photon absorption and scatter around brachytherapy sources can be characterized using the tissue attenuation factor, defined as the ratio of dose in water to water kerma in free space. In this study, the tissue attenuation factor along two major axes of a high dose rate (HDR) 192Ir source was determined by TLD measurements and MCNP Monte Carlo calculations.

Validity of the interval method for the determination of the anisotropy factor of high dose rate 192Ir sources.

Purpose: This study investigates the validity of the interval method to determine the anisotropy factors of high dose rate (HDR) 192Ir sources.

Methods And Materials: A calculation method, which is one of the various numerical implementations of the Sievert integral and known as the interval method, is applied to determine the anisotropy factors of a HDR 192Ir source. Calculated results from r = 1 cm to 10 cm are compared to published data.