Thermoluminescence dosimetry measurements of brachytherapy sources in liquid water

Journal Article · Mon Sep 15 04:00:00 EDT 2008 · Medical Physics

DOI:https://doi.org/10.1118/1.2968097· OSTI ID:21120914

Tailor, Ramesh; Tolani, Naresh; Ibbott, Geoffrey S ^[1]

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1. Radiation Physics, UT M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 94, Houston, Texas 77030 (United States)

Radiation therapy dose measurements are customarily performed in liquid water. The characterization of brachytherapy sources is, however, generally based on measurements made with thermoluminescence dosimeters (TLDs), for which contact with water may lead to erroneous readings. Consequently, most dosimetry parameters reported in the literature have been based on measurements in water-equivalent plastics, such as Solid Water. These previous reports employed a correction factor to transfer the dose measurements from a plastic phantom to liquid water. The correction factor most often was based on Monte Carlo calculations. The process of measuring in a water-equivalent plastic phantom whose exact composition may be different from published specifications, then correcting the results to a water medium leads to increased uncertainty in the results. A system has been designed to enable measurements with TLDs in liquid water. This system, which includes jigs to support water-tight capsules of lithium fluoride in configurations suitable for measuring several dosimetric parameters, was used to determine the correction factor from water-equivalent plastic to water. Measurements of several {sup 125}I and {sup 131}Cs prostate brachytherapy sources in liquid water and in a Solid Water phantom demonstrated a correction factor of 1.039{+-}0.005 at 1 cm distance. These measurements are in good agreement with a published value of this correction factor for an {sup 125}I source.

• OSTI ID: 21120914
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 9 Vol. 35; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BRACHYTHERAPY
CESIUM 131
CORRECTIONS
IODINE 125
LITHIUM FLUORIDES
MONTE CARLO METHOD
PHANTOMS
PROSTATE
RADIATION DOSES
THERMOLUMINESCENT DOSEMETERS
THERMOLUMINESCENT DOSIMETRY