Epithermal beam development at the BMRR (Brookhaven Medical Research Reactor): Dosimetric evaluation

Conference · Thu Aug 24 04:00:00 EDT 1989

OSTI ID:5473833

Saraf, S K; Fairchild, R G; Kalef-Ezra, J; Laster, B H; Fiarman, S; Ramsey, E ^[1]

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1. Brookhaven National Lab., Upton, NY (USA)

The utilization of an epithermal neutron beam for neutron capture therapy (NCT) is desirable because of the increased tissue penetration relative to a thermal neutron beam. Over the past few years, modifications have been and continue to be made at the Brookhaven Medical Research Reactor (BMRR) by changing its filter components to produce an optimal epithermal beam. An optimal epithermal beam should contain a low fast neutron contamination and no thermal neutrons in the incident beam. Recently a new moderator for the epithermal beam has been installed at the epithermal port of the BMRR and has accomplished this task. This new moderator is a combination of alumina (Al{sub 2}O{sub 3}) bricks and aluminum (Al) plates. A 0.51 mm thick cadmium (Cd) sheet has reduced the thermal neutron intensity drastically. Furthermore, an 11.5 cm thick bismuth (Bi) plate installed at the port surface has reduced the gamma dose component to negligible levels. Foil activation techniques have been employed by using bare gold and cadmium-covered gold foil to determine thermal as well as epithermal neutron fluence. Fast neutron fluence has been determined by indium foil counting. Fast neutron and gamma dose in soft tissue, free in air, is being determined by the paired ionization chamber technique, using tissue equivalent (TE) and graphite chambers. Thermoluminescent dosimeters (TLD-700) have also been used to determine the gamma dose independently. This paper describes the methods involved in the measurements of the above mentioned parameters. Formulations have been developed and the various corrections involved have been detailed. 12 refs.

• Research Organization: Brookhaven National Lab., Upton, NY (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 5473833
• Report Number(s): BNL-43271; CONF-8903150--4; ON: DE90001272
• Country of Publication: United States
• Language: English

Related Subjects

550603* -- Medicine-- External Radiation in Therapy-- (1980-)
62 RADIOLOGY AND NUCLEAR MEDICINE
BARYONS
BEAMS
BORON COMPOUNDS
DOSIMETRY
ELEMENTARY PARTICLES
EPITHERMAL NEUTRONS
FERMIONS
HADRONS
IMAGE PROCESSING
MATERIALS
MEDICINE
NEUTRON BEAMS
NEUTRON CAPTURE THERAPY
NEUTRON THERAPY
NEUTRONS
NUCLEAR MEDICINE
NUCLEON BEAMS
NUCLEONS
OPTIMIZATION
PARTICLE BEAMS
PROCESSING
RADIOLOGY
RADIOTHERAPY
THERAPY
THERMOLUMINESCENT DOSIMETRY
TISSUE-EQUIVALENT MATERIALS
USES