Neutron dosimetry for a general Cf-252 brachytherapy source

Authors
Citation
Mj. Rivard, Neutron dosimetry for a general Cf-252 brachytherapy source, MED PHYS, 27(12), 2000, pp. 2803-2815
Citations number
25
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
Journal title
MEDICAL PHYSICS
ISSN journal
00942405 → ACNP
Volume
27
Issue
12
Year of publication
2000
Pages
2803 - 2815
Database
ISI
SICI code
0094-2405(200012)27:12<2803:NDFAGC>2.0.ZU;2-7
Abstract
This paper extends previous work to characterize neutron dosimetry in the v icinity of Cf-252 brachytherapy sources. A general source is examined with an arbitrary length, diameter, and encapsulation using Monte Carlo methods. Fast neutron dosimetry and thermal neutron fluence rates were determined i n a variety of clinically relevant media of varying dimensions. Applicator Tube, point source, high dose rate VariSource, and high dose rate mu Select ron source geometries were analyzed. Fast neutron dosimetry was relatively independent of encapsulation thickness for an assortment of encapsulation m aterials less than 2 mm thick. Large variations in phantom size made minima l differences in the fast neutron dose close: to the source. Specific sourc e geometries were compared with dosimetry obtained from a simplified point model. The consequence of these results is a convenient means of accurately predicting clinical fast neutron dosimetry characteristics around a genera l Cf-252 brachytherapy source in a variety of media without requiring neutr on transport. Thermal neutron fluence rates were determined for a variety o f source encapsulation materials, encapsulation thicknesses, and phantom si zes. At a distance of 3 cm from the source center, the thermal neutron flue nce rate for a 30 cm diameter phantom was a 2.65 times greater than for a 1 0 cm diameter water phantom. These results demonstrate 252Cf thermal neutro n fluence rate is relatively independent of encapsulation thickness and com position, yet highly dependent on hydrogen mass density and phantom size fo r phanta with diameters <30 cm. (C) 2000 American Association of Physicists in Medicine. [S0094-2405(00)00712-4].