umin.ac.jp/ctr Identifier: C000000412.

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With advances in computer performance, the use of high-resolution voxel models of the entire human body has become more frequent in numerical dosimetries of electromagnetic waves. Using magnetic resonance imaging, we have developed realistic high-resolution whole-body voxel models for Japanese adult males and females of average height and weight. The developed models consist of cubic voxels of 2 mm on each side; the models are segmented into 51 anatomic regions. The adult female model is the first of its kind in the world and both are the first Asian voxel models (representing average Japanese) that enable numerical evaluation of electromagnetic dosimetry at high frequencies of up to 3 GHz. In this paper, we will also describe the basic SAR characteristics of the developed models for the VHF/UHF bands, calculated using the finite-difference time-domain method.

PURPOSEIt is not well known how the omission of whole-brain radiotherapy (WBRT) affects the neurocognitive function of patients with 1-4 brain metastases who are treated with stereotactic radiosurgery (SRS). MATERIALS AND METHODSIn a prospective randomized trial between WBRT+SRS and SRS-alone in patients with 1-4 brain metastases, neurocognitive function was assessed by the Mini-Mental Score Examination (MMSE). Among 132 enrolled patients, MMSE scores were available for 110 patients. RESULTSIn the baseline MMSE analyses, statistically significant differences were observed for total tumor volume, extent of tumor edema, age, and KPS. Among 92 patients who received follow-up MMSE, 39 patients had a baseline MMSE of 27 or lower (17 in the WBRT+SRS group, 22 in the SRS-alone group).Improvements of >=3 points in the MMSEs of 9 WBRT+SRS patients and 11 SRS-alone patients (P=0.85) were observed. Among 82 patients who had baseline MMSEs >=27 or whose baseline MMSEs were <=26 but improved to >=27 after the initial brain treatment, the 12-, 24-, and 36-month actuarial free Aoyama H et al. 4 rates of the 3-point drop in MMSE were 76.1%, 68.5%, and 14.7% in the WBRT+SRS group, and were 59.3%, 51.9%, and 51.9% in the SRS-alone group.The average duration until deterioration was 16.5 months in WBRT+SRS and 7.6 months in SRS-alone patients (P=0.05). CONCLUSIONSThe current study revealed that, for the majority of brain metastatic patients, control of the brain tumor is the most important factor for stabilizing neurocognitive function. However, the long-term adverse effect of WBRT on neurocognitive function may not be negligible.

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