Determination of exit skin dose for intracavitary accelerated partial breast irradiation with thermoluminescent dosimeters

Raffi, Julie A.; DeWerd, Larry A.; Micka, J; Kunugi, Keith A.; Davis, Stephen D.

doi:10.1016/j.brachy.2008.02.120

Cited by 10 publications

(15 citation statements)

References 15 publications

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“…However, their labor‐intensive signal readout process and individual calibration make their routine use impractical at clinical sites. The use of TLDs calibrated in high energy photon beams is further complicated due to their intrinsic energy dependence which is related to the linear energy transfer (LET) of secondary electrons and affected by annealing and readout conditions . EPR dosimeters made of lithium formate (LiFo) and alanine were shown to have dosimetric properties suitable for dosimetry of HDR 192 Ir BT sources but do not provide high spatial resolution due to their size (typically, diameter 5 mm, thickness 2.5 mm), exhibit intrinsic energy dependence, are time‐consuming to use and require dedicated readout equipment.…”

Section: Introductionmentioning

confidence: 99%

Suitability of microDiamond detectors for the determination of absorbed dose to water around high‐dose‐rate ¹⁹²Ir brachytherapy sources

et al. 2017

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Purpose: Experimental dosimetry of high-dose-rate (HDR) 192 Ir brachytherapy (BT) sources is complicated due to high dose and dose-rate gradients, and softening of photon energy spectrum with depth. A single crystal synthetic diamond detector microDiamond (PTW 60019, Freiburg, Germany) has a small active volume, high sensitivity, direct readout, and nearly water-equivalent active volume. The purpose of this study was to evaluate the suitability of microDiamond detectors for the determination of absorbed dose to water around HDR 192 Ir BT sources. Three microDiamond detectors were used, allowing for the comparison of their properties. Methods: In-phantom measurements were performed using microSelectron and VariSource iX HDR 192 Ir BT treatment units. Their treatment planning systems (TPSs), Oncentra (v. 4.3) and BrachyVision (v. 13.6), respectively, were used to create irradiation plans for a cubic PMMA phantom with the microDiamond positioned at one of three source-to-detector distances (SDDs) (1.5, 2.5, and 5.5 cm) at a time. The source was stepped in increments of 0.5 cm over a total length of 6 cm to yield absorbed dose of 2 Gy at the nominal reference-point of the detector. Detectors were calibrated in 60 Co beam in terms of absorbed dose to water, and Monte Carlo (MC) calculated beam quality correction factors were applied to account for absorbed-dose energy dependence. Phantom correction factors were applied to account for differences in dimensions between the measurement phantom and a water phantom used for absorbed dose calculations made with a TPS. The same measurements were made with all three of the detectors. Additionally, dose-rate dependence and stability of the detectors were evaluated in 60 Co beam. Results: The percentage differences between experimentally determined and TPS-calculated absorbed doses to water were from À1.3% to +2.9%. The values agreed to within experimental uncertainties, which were from 1.9% to 4.3% (k = 2) depending on the detector, SDD and treatment delivery unit. No dose-rate or intrinsic energy dependence corrections were applied. All microDiamonds were comparable in terms of preirradiation dose, stability of the readings and energy response, and showed a good agreement. Conclusions:The results indicate that the microDiamond is potentially suitable for the determination of absorbed dose to water around HDR 192 Ir BT sources and may be used for independent verification of TPS's calculations, as well as for QA measurements of HDR 192 Ir BT treatment delivery units at clinical sites.

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Section: Introductionmentioning

confidence: 99%

Suitability of microDiamond detectors for the determination of absorbed dose to water around high‐dose‐rate ¹⁹²Ir brachytherapy sources

et al. 2017

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“…Monte Carlo studies [26][27][28][29][30][31][32] showed that TPS calculations overestimate doses in breast brachytherapy owing to tissue inhomogeneity, contrast in balloon and finite patient dimension. The dose rate overestimation at the prescription line was up to approximately 10%.…”

Section: Discussionmentioning

confidence: 98%

“…26,27 Skin dose was overestimated up to 15%. 28,29 The radiopaque iodinebased contrast solution filled in the balloon reduced the dose rate at the prescription line up to approximately 6% 30-32 at contrast concentration of 25%. Limiting the contrast concentration to 10% would ensure that less than 3% reduction in the PD owing to contrast agent.…”

Section: Discussionmentioning

confidence: 99%

Dosimetric experience with 2 commercially available multilumen balloon-based brachytherapy to deliver accelerated partial-breast irradiation

Kim

Chen

et al. 2015

Medical Dosimetry

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“…30 The percent difference between the TPS and TLD measurement skin doses was found in the range from -15% to 44%. 35 The peripheral doses at 20cm away from the target area was found 2.52 cGy and 2.07 cGy using TLDs in LINAC and tomotherapy delivery correspondingly, for a planning target volume (PTV) dose of 200 cGy. 36 However, the surface dose measurement outside the treatment area at several points of interest in a real patient using TLDs is limited.…”

Section: Introductionmentioning

confidence: 97%

Evaluation of surface dose outside the treatment area for five breast cancer irradiation modalities using thermo-luminescent dosimeters

Khànal

2015

Int J Cancer Ther Oncol

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Evaluation of surface dose outside the treatment area for five breast cancer irradiation modalities using thermo-luminescent dosimeters Original Article AbstractPurpose: To measure and compare the surface dose outside the treatment area at six different points of interest (POIs) for five different breast cancer radiation treatment modalities by using thermo-luminescent dosimeters (TLDs). This experiment will evaluate the magnitude of the dose due to scatter and leakage radiation at different areas outside the target on a patient that could potentially lead, in the long term, to radiation induced secondary malignancies. Methods: TLD-100 were calibrated according to the University of Wisconsin Radiation Calibration Laboratory protocol and then used for dose measurements at selected POIs namely sternum, lower abdomen, contralateral breast, thyroid, shoulder, and eye. Twenty five breast cancer patients and the following modalities were included in this study: Strut-adjusted volume implant (SAVI), mammosite multi-lumen (ML), Accuboost, electron boost and photon boost. The surface doses in all patients were measured in a single fraction. The delivered target doses were normalized to 200 cGy. Finally, breast quadrant analysis was performed. Results: The maximum average dose for each POI was as follows: Sternum 6.51 cGy (SD 2.93), lower abdomen 4.50 cGy (SD 2.63), contralateral breast 8.52 cGy (SD 3.86), thyroid 5.50 cGy (SD 2.75), shoulder 5.58 cGy (SD 2.77), and eye 2.65 cGy (SD 0.68). The highest POI dose of 15.84 cGy was found in contralateral breast. Conclusion: The measured surface dose at each POI varies with the modality of treatment. The surface doses show a strong correlation to the tumor bed location in the breast quadrant. The SAVI, electron boost, and photon boost modalities had delivered smaller surface dose at POIs than the Accuboost and Mammosite ML modalities. While the measured doses fall within the low range, its significance in producing second malignancies would require a large cohort of patients and a longer follow up.

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Determination of exit skin dose for intracavitary accelerated partial breast irradiation with thermoluminescent dosimeters

Cited by 10 publications

References 15 publications

Suitability of microDiamond detectors for the determination of absorbed dose to water around high‐dose‐rate ¹⁹²Ir brachytherapy sources

Suitability of microDiamond detectors for the determination of absorbed dose to water around high‐dose‐rate ¹⁹²Ir brachytherapy sources

Dosimetric experience with 2 commercially available multilumen balloon-based brachytherapy to deliver accelerated partial-breast irradiation

Evaluation of surface dose outside the treatment area for five breast cancer irradiation modalities using thermo-luminescent dosimeters

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Determination of exit skin dose for intracavitary accelerated partial breast irradiation with thermoluminescent dosimeters

Cited by 10 publications

References 15 publications

Suitability of microDiamond detectors for the determination of absorbed dose to water around high‐dose‐rate 192Ir brachytherapy sources

Suitability of microDiamond detectors for the determination of absorbed dose to water around high‐dose‐rate 192Ir brachytherapy sources

Dosimetric experience with 2 commercially available multilumen balloon-based brachytherapy to deliver accelerated partial-breast irradiation

Evaluation of surface dose outside the treatment area for five breast cancer irradiation modalities using thermo-luminescent dosimeters

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Suitability of microDiamond detectors for the determination of absorbed dose to water around high‐dose‐rate ¹⁹²Ir brachytherapy sources

Suitability of microDiamond detectors for the determination of absorbed dose to water around high‐dose‐rate ¹⁹²Ir brachytherapy sources