Impact of radiation attenuation by a carbon fiber couch on patient dose verification.

The aim of this study was to understand the difference between the measured and calculated irradiation attenuations obtained using two algorithms and to identify the influence of couch attenuation on patient dose verification. We performed eight tests of couch attenuation with two photon energies, two longitudinal couch positions, and two rail positions. The couch attenuation was determined using a radiation treatment planning system.

A study on the dose distributions in various materials from an Ir-192 HDR brachytherapy source.

Dose distributions of (192)Ir HDR brachytherapy in phantoms simulating water, bone, lung tissue, water-lung and bone-lung interfaces using the Monte Carlo codes EGS4, FLUKA and MCNP4C are reported. Experiments were designed to gather point dose measurements to verify the Monte Carlo results using Gafchromic film, radiophotoluminescent glass dosimeter, solid water, bone, and lung phantom. The results for radial dose functions and anisotropy functions in solid water phantom were consistent with previously reported data (Williamson and Li).

Air kerma standard and measurement comparison on source strength determination for high-dose rate 192Ir brachytherapy in Taiwan.

This paper describes the establishment by the Institute of Nuclear Energy Research (INER, Taiwan) of the reference air kerma rate (RAKR) calibration standard for measurement of high-dose rate (HDR) (192)Ir brachytherapy source strength. A bilateral comparison has been made in the RAKR standards for HDR (192)Ir brachytherapy sources at the INER and Physikalisch-Technische Bundesanstalt (PTB, Germany) and the measurement difference was within the overall standard uncertainty and showed good agreement between the two calibration standard systems established at the INER and the PTB. Besides, INER also worked with 20 domestic hospitals to organise an on-site measurement comparison programme to explore the status of HDR (192)Ir brachytherapy source strength determination in Taiwan.

Dose measurements for gamma knife with radiophotoluminescent glass dosemeter and radiochromic film.

Stereotactic radiosurgery (SRS) is designed for patients with small lesion areas that are not suitable for actual surgery. SRS delivers high dose to the lesion with high gradient on the irradiation margin area. In this study, radiophotoluminescent glass dosemeter (RPLGD) and radiochromic film were used to measure the output factor of a gamma knife.

A statistical approach to infer the minimum setup distance of a well chamber to the wall or to the floor for 192Ir HDR calibration.

We propose a new method based on statistical analysis technique to determine the minimum setup distance of a well chamber used in the calibration of 192Ir high dose rate (HDR). The chamber should be placed at least this distance away from any wall or from the floor in order to mitigate the effect of scatter. Three different chambers were included in this study, namely, Sun Nuclear Corporation, Nucletron, and Standard Imaging.

The absolute counting of 166mHo, 58Co and 88Y.

In this study, absolute 4pi beta-gamma-coincidence counting was used to measure the mass activity of 166mHo, 58Co and 88Y. For 166mHo and 88Y, three gamma windows were set to study the systematic error caused by the different gamma window settings. To eliminate the effect arising from the large difference in counting efficiency of the 4pi beta counter between electron capture events and beta+ particles, the two-dimensional extrapolation method was used to measure 58Co.