1992 Fiscal Year Final Research Report Summary
Depth-dose evaluation for gadolinium neutron capture therapy
| Project/Area Number |
03680197
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Nuclear engineering
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| Research Institution | Musashi Institute of Technology |
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Principal Investigator |
MATSUMOTO Tetsuo Atomic Energy Research Lab. Musashi Institute of Tech. Assistant Professor, 原子力研究所, 講師 (00139411)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Gadolinium / Neutron capture / Neutron transport code / Dose distribution / capture gamma-rays / Internal conversion electrons / Phantom |
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| Research Abstract |
The isotope gadolinium (^<157>Gd) has been suggested as an alternative neutron capture (NCT) agent to ^<10>B. Possible advantages of Gd-NCT are as follows : (i) thermal neutron cross sections (245,000 barn) for ^<157>Gd is 66 times larger than that of ^<10>B. (ii) gadolinium neutron capture reactions produce prompt gamma-rays with relatively low energy accompanying by emission of low energy conversion and Auger electrons. (iii) gadolinium is used as a contrast medium for magnetic resonance imaging (MRI) and may lead to an effective Gd-NCT compound.
In this study the depth-dose distributions were evaluated by phantom experiments and calculations for possible application of Gd-NCT. The experiments were carried out at the irradiation port in the experimental beam hole (7R) of JRR3M. The distributions of thermal neutron flux and gamma-ray dose rate in a tumor-simulated phantom were measured by gold foil activation, TLDs and film methods. A two-dimensional neutron-coupled gamma-ray transport code (DOT3.5) was also employed for the calculations of neutron and capture gamma-ray fluence rates.
The calculations and experiments showed that (i) a significant dose can be delivered to a tumor when Gd is accumulated in the tumor. (ii) the dose distribution was a function of storongly interrelated parameters such as gadolinium concentrations, tumor site and collimator aperture (neutron beam size). (iii) the Gd-NCT by thermal neutrons appears to be strong potential for treatment of superficial tumors.
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