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Your search keyword '"Tadayuki Kotsuma"' showing total 3 results
Start Over Author "Tadayuki Kotsuma" Journal radiation oncology
3 results on '"Tadayuki Kotsuma"'

1. Quantitative assessment of inter-observer variability in target volume delineation on stereotactic radiotherapy treatment for pituitary adenoma and meningioma near optic tract

Author

Koichi Yamashita, Norihiro Aibe, Hiroya Shiomi, Yoshimi Baba, Takuji Tsubokura, Manabu Nishikata, Takuya Nishimura, Tadayuki Kotsuma, Hideya Yamazaki, Mikio Ogita, Hiroki Udono, and Naohiro Kodani

Subjects
lcsh:Medical physics. Medical radiology. Nuclear medicine, Adenoma, Male, Organs at Risk, lcsh:R895-920, medicine.medical_treatment, Pituitary neoplasm, Radiosurgery, lcsh:RC254-282, Meningioma, Cyberknife, Pituitary adenoma, Image Interpretation, Computer-Assisted, Humans, Medicine, Pituitary Neoplasms, Visual Pathways, Radiology, Nuclear Medicine and imaging, Observer Variation, Contouring, business.industry, Research, Radiotherapy Planning, Computer-Assisted, Organ Size, Middle Aged, lcsh:Neoplasms. Tumors. Oncology. Including cancer and carcinogens, medicine.disease, Tumor Burden, Oncology, Radiology Nuclear Medicine and imaging, Optic nerve, Female, business, Nuclear medicine
Abstract

Background To assess inter-observer variability in delineating target volume and organs at risk in benign tumor adjacent to optic tract as a quality assurance exercise. Methods We quantitatively analyzed 21 plans made by 11 clinicians in seven CyberKnife centers. The clinicians were provided with a raw data set (pituitary adenoma and meningioma) including clinical information, and were asked to delineate the lesions and create a treatment plan. Their contouring and plans (10 adenoma and 11 meningioma plans), were then compared. In addition, we estimated the influence of differences in contouring by superimposing the respective contours onto a default plan. Results The median planning target volume (PTV) and the ratio of the largest to the smallest contoured volume were 9.22 cm3 (range, 7.17 - 14.3 cm3) and 1.99 for pituitary adenoma, and 6.86 cm3 (range 6.05 - 14.6 cm3) and 2.41 for meningioma. PTV volume was 10.1 ± 1.74 cm3 for group 1 with a margin of 1 -2 mm around the CTV (n = 3) and 9.28 ± 1.8 cm3(p = 0.51) for group 2 with no margin (n = 7) in pituitary adenoma. In meningioma, group 1 showed larger PTV volume (10.1 ± 3.26 cm3) than group 2 (6.91 ± 0.7 cm3, p = 0.03). All submitted plan keep the irradiated dose to optic tract within the range of 50 Gy (equivalent total doses in 2 Gy fractionation). However, contours superimposed onto the dose distribution of the default plan indicated that an excessive dose 23.64 Gy (up to 268% of the default plan) in pituitary adenoma and 24.84 Gy (131% of the default plan) in meningioma to the optic nerve in the contours from different contouring. Conclusion Quality assurance revealed inter-observer variability in contour delineation and their influences on planning for pituitary adenoma and meningioma near optic tract.

Published
2011
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2. Predictive value of skin invasion in recurrent head and neck cancer patients treated by hypofractionated stereotactic re-irradiation using a cyberknife.

Author

Hideya Yamazaki, Mikio Ogita, Kengo Himei, Satoaki Nakamura, Gen Suzuki, Tadayuki Kotsuma, Ken Yoshida, Yasuo Yoshioka, Yamazaki, Hideya, Ogita, Mikio, Himei, Kengo, Nakamura, Satoaki, Suzuki, Gen, Kotsuma, Tadayuki, Yoshida, Ken, and Yoshioka, Yasuo

Subjects
HEAD & neck cancer, STEREOTACTIC radiotherapy, IRRADIATION, SKIN tumors, PROGNOSIS, INTENSITY modulated radiotherapy, IMAGE-guided radiation therapy, CANCER relapse, HEAD tumors, NECK tumors, RADIOSURGERY, RETROSPECTIVE studies, KAPLAN-Meier estimator, SURGERY
Abstract

Background: This study aimed to elucidate the influence of skin invasion in patients with recurrent head and neck cancer treated with re-irradiation using stereotactic radiotherapy.Materials: We reviewed 104 patients treated using CyberKnife in four institutions.Results: Nine cases of skin invasion were recognized (8.6 %). Larger tumors tended to exhibit skin invasion. The skin invasion (+) group showed a lower response rate (0/9, 0 %) than the skin invasion (-) group (56/95, 59 %) (p = 0.002). The skin invasion (+) group showed lower local control (LC) and progression free survival (PFS) rates, both 0 % at 6 months, than the skin invasion (-) group, which had a LC of 69 % (p = 0.0001) and a PFS of 48 % at 1 year (p = 0.0157). Median survival time and one-year survival rates for the skin invasion (+) and (-) groups were 6.6 vs. 15.3 months and 14 % vs. 59 % (p = 0.0005), respectively. No patient with skin invasion survived more than 14.4 months. The percentage of patients who developed grade 3 or higher toxicity was 44 % in the skin invasion (+) group and 18 % in the skin invasion (-) group (p = 0.14).Conclusions: Skin invasion is an important predictor of poor prognosis in recurrent head and neck cancer after re-irradiation with stereotactic radiation therapy. [ABSTRACT FROM AUTHOR]

Published
2015
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3. A Japanese prospective multi-institutional feasibility study on accelerated partial breast irradiation using interstitial brachytherapy: treatment planning and quality assurance.

Author

Yuki Otani, Takayuki Nose, Takushi Dokiya, Toshiaki Saeki, Yu Kumazaki, Shuuji Asahi, Iwao Tsukiyama, Ichirou Fukuda, Hiroshi Sekine, Naoto Shikama, Takao Takahashi, Ken Yoshida, Tadayuki Kotsuma, Norikazu Masuda, Eisaku Yoden, Kazutaka Nakashima, Taisei Matsumura, Shino Nakagawa, Seiji Tachiiri, and Yoshio Moriguchi

Subjects
RADIOISOTOPE brachytherapy, QUALITY assurance, BREAST cancer patients, FEASIBILITY studies, PARAMETERS (Statistics)
Abstract

Background: In Japan, breast-conserving surgery with closed cavity has generally been performed for breast cancer patients, and accelerated partial breast irradiation (APBI) is considered difficult because Asian females generally have smaller breast sizes than Western females. Therefore, common identification of target and treatment plan method in APBI is required. A prospective multicenter study was conducted in Japan to determine institutional compliance with APBI using high-dose-rate interstitial brachytherapy (ISBT) designed for Japanese female patients. Methods: For this study, 46 patients were recruited at eight institutions from January 2009 to December 2011. The reproducibility of the ISBT-APBI plan was evaluated using three criteria: (1) minimum clinical target volume dose with a clip dose ≥ 6 Gy/fraction, (2) irradiated volume constraint of 40-150 cm3, and (3) uniformity of dose distribution, expressed as the dose non-uniformity ratio (DNR, V150/V100) < 0.35. The ISBT-APBI plan for each patient was considered reproducible when all three criteria were met. When the number of non-reproducible patients was ≤ 4 at study completion, APBI at this institution was considered statistically reproducible. Results: Half of the patients (52 %) had a small bra size (A/B cup). The mean values of the dose-constrained parameters were as follows: Vref, 117 cm3 (range, 40-282), DNR, 0.30 (range, 0.22-0.51), and clip dose, 784 cGy (range, 469-3146). A total of 43/46 treatment plans were judged to be compliant and ISBT-APBI was concluded to be reproducible. Conclusions: This study showed that multi-institutional ISBT-APBI treatment plan was reproducible for small breast patient with closed cavity. [ABSTRACT FROM AUTHOR]

Published
2015
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