1996 Fiscal Year Final Research Report Summary
Optimization of Ir-192 high-dose rate intraluminal brachytherapy for superficial esophageal cancer
| Project/Area Number |
07671005
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Radiation science
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
HIROKAWA Yutaka Hiroshima University, School of Medicine, Associate Proffessor, 医学部, 助教授 (40116653)
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| Co-Investigator(Kenkyū-buntansha) |
AKAGI Yukio Hiroshima University, Medical Hospital, Research Associate, 医学部附属病院, 助手 (40222509)
TANAKA Shinji Hiroshima University, Medical Hospital, Research Associate, 医学部附属病院, 助手 (00260670)
HIRAI Toshihiro Hiroshima University, Research Institute for Radiation Biology and Medicine, Ass, 原爆放射能医学研究所, 助教授 (60165149)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Esophageal cancer / Superficial cancer / Radiation therapy / Intraluminal irradiation / Dose calculation / Optimization / Treatment outcome / Complication |
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| Research Abstract |
Intraluminal brachytherapy using Iridium-192 high-dose rate remote afterloading system (Ir-192 HDR-RALS) is a foreseeable modality to treat esophageal cancer. To investigate optimum dose for esophageal brachytherapy, we calculated the mucosal surface dose and reference dose at a depth of 5 mm for given parameters such as source intensity, diameter of applicator, step distance of source movement, and mode of dose calculation. According to computationwith non-optimized method, dose profile on longitudinal axis was poor in homogeneity. Dose calculation with optimization worked well to obtain homogenous dose distribution.
To investigate an effective and safe fraction dose and number of intraluminal brachytherapy following external irradiation for superficial esophageal cancer treated with an Ir-192 HDR-RALS,35 consecutive patients with superficial esophageal cancer were analyzed. All patients were treated with external beam irradiation with doses ranging from 50 to 61 Gy, and intraluminal brachytherapy boost with double balloon applicator was used by Ir-192 HDR-RALS.Six (17%) of the 35 patients recurred and 7 (20%) had late complication (esophageal ulcer).
Univariate analysis showed that significant treatment parameters for late complication include total mucosal dose, fraction number and intraluminal mucosal dose. The probability of local recurrence was not influenced by the patient characteristics nor treatment parameters. We would recommend that the fraction dose is to be decreased to less than 2.5 Gy and the fraction number is to be increased more than 4 times in order to reduce esophageal ulcer.
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