[Comparison of setup accuracy between ExacTrac X-ray 6 dimensions and cone-beam computed tomography for intracranial and pelvic image-guided radiotherapy].

The aim of this study was to compare the setup difference measured with ExacTrac X-ray 6D (ETX6D) and cone-beam computed tomography (CBCT) for non-invasive fractionated radiotherapy. Setup data were collected on a Novalis Tx treatment unit for both a head phantom and patients with intracranial tumors and a pelvic phantom and patients with prostate cancer. Initially, setup was done for a phantom using ETX6D.

[Influence of high-definition multileaf collimator for three-dimensional conformal radiotherapy and intensity-modulated radiotherapy of prostate cancer].

The focus of this work is to evaluate the dosimetric impact of treatment planning for three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) of prostate cancer using Varian/BrainLAB 120-leaf high-definition multileaf collimator (HD120 MLC) with 2.5 mm leaf width and Varian 120-leaf millennium multileaf collimator (M120 MLC) with 5 mm leaf width. We measured the leaf transmission and dosimetric leaf gap (DLG) of two multileaf collimator (MLC) systems using Farmer ionization chamber.

[Evaluation on the effect of dosimetry using a depth of calibration point or a depth of temporary dose maximum in high energy electron beams.].

The Japan Society of Medical Physics (JSMP) has published a new dosimetry protocol "JSMP-01" for the calibration of radiotherapy beams. This protocol provides a new definition of the calibration point (depth) in order to obtain the absorbed dose at a reference point (D(r)) by the calculation in high energy electron beams. This study evaluated the difference in the absorbed dose at the depth dose maximum (D(dmax)) and D(r) calculated from the absorbed dose at the calibration point.

Methodology development for quantitative optimization of security enhancement in medical information systems -Case study in a PACS and a multi-institutional radiotherapy database-.

The target of our study is to establish the methodology for analyzing level of security requirements, for searching suitable security measures and for optimizing security distribution to every portion of medical practice. Quantitative expression must be introduced to our study as possible for the purpose of easy follow up of security procedures and easy evaluation of security outcomes or results. Results of system analysis by fault tree analysis (FTA) clarified that subdivided system elements in detail contribute to much more accurate analysis.

[Survey of bone mineral density in residents of selected areas of Hiroshima prefecture: effects of age and constitution on bone mineral density].

Because the complications of decreased bone mineral density, such as femoral neck fractures and severe spinal deformities, have a strong impact on daily life, prevention has become more important than therapy. The present study included as subjects 771 women residing in Innoshima City, Sera-gun, and Mihara City, all in Hiroshima Prefecture. We determined bone mineral density in the lumbar spine and femoral neck of these women, measured their height and weight, and examined the effect of age and body mass index (BMI) on bone density rate (YAM%).