Brachytherapy in Japan

This study aimed to assess the current state of brachytherapy (BT) resources, practices and resident education in Japan. A nationwide survey was undertaken encompassing 177 establishments facilitating BT in 2022. Questionnaires were disseminated to each BT center, and feedback through online channels or postal correspondence was obtained. The questionnaire response rate was 90% (159/177), and every prefecture had a response in at least one center. The number of centers in each prefecture ranged from 0.6 to 3.6 (median: 1.3) per million population. The annual number of patients in each center ranged from 0 to 272 (median: 31). While most prefectures provided intracavitary (IC) BT for gynecological cancers and interstitial (IS) BT for prostate cancer, only one-third of the prefectures provided IS BT for cancer sites other than the prostate. The institutional image-guided BT implementation rate was 71%. IC and IS BT was performed for 15.4% of IC BT cases of gynecological cancer. Only 47% of the BT training centers answered that they could provide adequate training in BT for residents. The most common reason for this finding was the insufficient number of patients in each center. The results show that, although BT has achieved uniformity in terms of facility penetration, new technologies are not yet widespread enough. Furthermore, IS BT, which requires advanced skills, is limited to a few BT centers, and considerable number of BT training centers do not have sufficient caseloads to provide the necessary experience for their residents

機能的MR撮影法による頭頸部腫瘍の診断と早期治療効果判定の検討

application/pdfMRI を用いた血流と拡散の研究は、脳腫瘍で活発に行われ臨床的にも有用性が確立しているが、頭頸部腫瘍においては十分に検討がされていない。本研究の目的は、3 テスラMRI を使い、頭頸部腫瘍における血流と拡散の情報を非侵襲的に取得する新たな撮影法とそれらのデータを定量評価するための解析ソフトウェアを開発することである。ターボスピンエコー法を用いたarterial spin labelingという血流撮像法と拡散強調画像で頭頚部腫瘍の定量的評価法の確立を試みた。血流量と拡散の情報を解析するソフトウェアを使うことで頭頚部腫瘍の診断で良悪性の鑑別が可能となり、腫瘍の質的診断に有用であることを証明した。Pseudocont inuous arterial spin labeling (pCASL) imaging enables noninvasive quantification of tumor blood flow in the head and neck. The purpose of this study was to compare echo-planar (EP) and turbo spin-echo (TSE) sequences of pCASL, to demonstrate the clinical applications and usefulness of this method in the diagnosis of particular diseases via both tumor blood flow (TBF) quantification and the apparent diffusion coefficient (ADC) obtained by diffusion-weighted imaging (DWI), and to demonstrate changes in TBF after chemoradiation treatments. TSE pCASL showed less image torsion and higher lesion conspicuity than EP pCASL. Combination of TSE pCASL and ADC enabled to differentiate benign parotid tumors from malignant parotid tumors. TBF changes were observed in head and neck squamous cell carcinomas in response to chemoradiation at an early stage. This study showed that the combination of pCASL and ADC is a promising tool for head and neck tumors.2016年度～2021年度科学研究費補助金(基盤研究(C))研究成果報告書16K1031