Comparison of measured backscatter factors with Monte Carlo simulations for low energy X-ray

Kim, Min Suk; Ryu, Jun Seok; Park, Shin-Woong; Ye, Yun

doi:10.1016/j.nima.2006.05.152

Cited by 4 publications

(1 citation statement)

References 7 publications

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“…In previous work, B w have been experimentally determined using specially designed parallel-plate ionisation chambers or small thermoluminescent dosimeters [14][15][16][17][18]. For these reasons, the B W in the reference dosimetry protocols has largely been determined via Monte Carlo simulations [6,11,13,[19][20][21].…”

Section: Introductionmentioning

confidence: 99%

The measurement of backscatter factors of kilovoltage X-ray beams using Gafchromic™ EBT2 film

Smith

Hill

Nakano

et al. 2011

Australas Phys Eng Sci Med

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Backscatter factors are essential in the determination of radiation dose for kilovoltage X-ray beams. The accurate measurement of backscatter factors in water (B (W)) is difficult and published values are based largely on Monte Carlo calculations. A number of studies have found that the measurement of B (W) in the energy range from 50 to 300 kVp is possible using Gafchromic EBT film, but this film is no longer commercially available. In this work, we evaluated whether the newer Gafchromic EBT2 film is suitable for the determination of B (W) for kilovoltage X-ray beams. B (W) were measured with Gafchromic EBT2 film for beam qualities of 50, 100 and 280 kVp and field sizes of 2, 3, 4 and 6 cm diameter and compared with tabulated values published in the AAPM TG-61 protocol. We found that rotation of the film position during readout had a small but non-negligible effect on the optical density readings. The agreement between measured and published B (W) was better than 3%, with the largest difference of occurring for the 2 cm diameter field with the 50 kVp X-ray beam. However, these differences are consistent with the total estimated uncertainty for the measurements, as calculated by the ISO GUM. Our results demonstrate that Gafchromic EBT2 film is a suitable dosimeter for B (W) measurements for clinical kilovoltage X-ray beams.

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Section: Introductionmentioning

confidence: 99%

The measurement of backscatter factors of kilovoltage X-ray beams using Gafchromic™ EBT2 film

Smith

Hill

Nakano

et al. 2011

Australas Phys Eng Sci Med

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Radiation dose measurements of an on-board imager X-ray unit using optically-stimulated luminescence dosimeters

Smith

Haque

Morales

et al. 2015

Australas Phys Eng Sci Med

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Cone beam computed tomography (CBCT) is now widely used to image radiotherapy patients prior to treatment for the purpose of accurate patient setup. However each CBCT image delivered to a patient increases the total radiation dose that they receive. The measurement of the dose delivered from the CBCT images is not readily performed in the clinic. In this study, we have used commercially available optically stimulated luminescence (OSLD) dosimeters to measure the dose delivered by the Varian OBI on a radiotherapy linear accelerator. Calibration of the OSLDs was achieved by using a therapeutic X-ray unit. The dose delivered by a head CBCT scan was found to be 3.2 ± 0.3 mGy which is similar in magnitude to the dose of a head computed tomography (CT) scan. The results of this study suggest that the radiation hazard associated with CBCT is of a similar nature to that of conventional CT scans. We have also demonstrated that the OSLDs are suitable for these low X-ray dose measurements.

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Advances in kilovoltage x-ray beam dosimetry

et al. 2014

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This topical review provides an up-to-date overview of the theoretical and practical aspects of therapeutic kilovoltage x-ray beam dosimetry. Kilovoltage x-ray beams have the property that the maximum dose occurs very close to the surface and thus, they are predominantly used in the treatment of skin cancers but also have applications for the treatment of other cancers. In addition, kilovoltage x-ray beams are used in intra operative units, within animal irradiators and in on-board imagers on linear accelerators and kilovoltage dosimetry is important in these applications as well. This review covers both reference and relative dosimetry of kilovoltage x-ray beams and provides recommendations for clinical measurements based on the literature to date. In particular, practical aspects for the selection of dosimeter and phantom material are reviewed to provide suitable advice for medical physicists. An overview is also presented of dosimeters other than ionization chambers which can be used for both relative and in vivo dosimetry. Finally, issues related to the treatment planning and the use of Monte Carlo codes for solving radiation transport problems in kilovoltage x-ray beams are presented.

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Comparison of measured backscatter factors with Monte Carlo simulations for low energy X-ray

Cited by 4 publications

References 7 publications

The measurement of backscatter factors of kilovoltage X-ray beams using Gafchromic™ EBT2 film

The measurement of backscatter factors of kilovoltage X-ray beams using Gafchromic™ EBT2 film

Radiation dose measurements of an on-board imager X-ray unit using optically-stimulated luminescence dosimeters

Advances in kilovoltage x-ray beam dosimetry

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