The Use of a Spreadsheet Computer Program to Expedite TLD Reporting

Wolf, Darrell; Dean, Robert; Cytacki, Edmund P.; Evans, Richard

doi:10.1016/0958-3947(89)90183-0

Cited by 1 publication

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“…Hence, a single chip lying free on the surface has 0 neighbours (geometry A), a chip fitting in a 1 mm deep hole of solid water has 4 neighbours (geometry B) and two TLDs next to each other free lying on the surface have 2.2 neighbours each (1 x 2.2 the relative electron density of LiF f3 x 0 for the surrounding air). The latter arrangement which is commonly used in radiotherapy physics to have at least two readings per measurement point (Gooden and Brickner 1972, Wolf et al 1989, Kron et ai 1990 increases the dose measured by each chip on the surface by up to 1%. This systematic error is too small to be picked up in clinical practice of in vivo dosimetry on patients, but it should not be neglected in phantom measurements.…”

Section: Measurements With Tl Dosimeters In Contact With Each Othermentioning

confidence: 99%

Thermoluminescence dosimetry of therapeutic X-rays with LiF ribbons and rods

1993

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Exhuded LiF ribbons (3.1 x 3.1 x 0.9 mm') and rods (6 x 1 x I mm3) we commonly used thermoluminescence dosimeters (n dosimeters) for clinical dosimetry in radiotherapy. The dose distribution in these crystals was investigated in a 6 MV x-ray beam using s d e z LiF n dosimeter types (thin ribbons with a thickness of 0.14 mm and small cubes with 1 nun side length). Using the thin ribbons, the effective depth of measurement in the normal ribbons was found to be shifted towards the surface. Measuring on the surface of a solid water phantom in a IO x 10 emz field it was found to be at a depth of 0.4 mm as compared to the physical centre of the ribbons of 0.44 mm. In the investigations with small cubes assembled in form of ribbons and rods it was found that a higher &se was deposited in the centre of the ribbons and mds. Accordingly it was found that n. dosimeters in close contact w i t h each other increase their respective reading. Using two ribbons in contact with each other on the surface of a phantom leads to an overestimation of dose of about 1%. The specific dose response of LiF increases with dosimeter size. this is most likely due to increased e l m " scatter from the additional LiF material with density higher than unity. This emphasizes the role of n dosimeters as relative dosimeters where siandards of equal size and geamey should be used to evaluate the readings.

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Section: Measurements With Tl Dosimeters In Contact With Each Othermentioning

confidence: 99%