Evaluation of the surface radiation dose and dose gradient in early stage breast cancer using high-dose-rate brachytherapy MammoSite™ applicator

Sadeghi, Amir; Prestidge, Bradley R.; Lee, Jui-Min; Rosenthal, Arthur

doi:10.1016/j.brachy.2006.02.004

Cited by 15 publications

(7 citation statements)

References 19 publications

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“…This is considerably lower than the same ratio for the MammoSite applicator as recently published by Sadeghi et al [10]. The average dose ratio of 78% between prescribed and maximum skin dose found in the study is likely to reflect the differences in attenuation between the 50 kVp X-ray source used in the present study and the 192-Ir HDR brachytherapy source employed in the MammoSite device.…”

Section: Discussionmentioning

confidence: 34%

Thermoluminescence dosimetry for skin dose assessment during intraoperative radiotherapy for early breast cancer

Fogg

Das

Kron

et al. 2010

Australas Phys Eng Sci Med

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Dosimetry for intraoperative radiotherapy (IORT) after wide local excision for breast cancer using a 50 kV X-ray needle (Intrabeam) was performed in vivo using thermoluminescence dosimetry. Eight LiF:Mg,Ti chips were placed on the skin around the incision site after wide local excision while the tumour bed was irradiated to a prescribed dose of 5 Gy 10 mm from the applicator surface. The maximum and mean measured skin dose for 57 patients ranged from 0.64 to 7.1 Gy and 0.56 to 4.78 Gy, respectively, reflecting different tissue thicknesses overlying the applicator. The average maximum dose of 2.93+/-1.46 Gy was below the threshold for severe radiation skin toxicity.

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Section: Discussionmentioning

confidence: 34%

Thermoluminescence dosimetry for skin dose assessment during intraoperative radiotherapy for early breast cancer

Fogg

Das

Kron

et al. 2010

Australas Phys Eng Sci Med

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“…A similar reduction should apply with Ir-192 where Skowronek et al [ 45 ] find skin doses (D max ) of 81.34-85.83% of prescription dose when calculated in water. This is confirmed by measurements of skin dose by Sadeghi et al [ 47 ] who find average skin doses of 78.5% (range 56-488cGy, average 267cGy for a prescription dose of 340cGy) depending on tumor depth and size of applicator.…”

Section: Main Textsupporting

confidence: 71%

Present state and issues in IORT Physics

Hensley

2017

Radiat Oncol

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Literature was reviewed to assess the physical aspects governing the present and emerging technologies used in intraoperative radiation therapy (IORT). Three major technologies were identified: treatment with electrons, treatment with external generators of kV X-rays and electronic brachytherapy. Although also used in IORT, literature on brachytherapy with radioactive sources is not systematically reviewed since an extensive own body of specialized literature and reviews exists in this field. A comparison with radioactive sources is made in the use of balloon catheters for partial breast irradiation where these are applied in almost an identical applicator technique as used with kV X-ray sources. The physical constraints of adaption of the dose distribution to the extended target in breast IORT are compared. Concerning further physical issues, the literature on radiation protection, commissioning, calibration, quality assurance (QA) and in-vivo dosimetry of the three technologies was reviewed. Several issues were found in the calibration and the use of dosimetry detectors and phantoms for low energy X-rays which require further investigation. The uncertainties in the different steps of dose determination were estimated, leading to an estimated total uncertainty of around 10-15% for IORT procedures. The dose inhomogeneity caused by the prescription of electrons at 90% and by the steep dose gradient of kV X-rays causes additional deviations from prescription dose which must be considered in the assessment of dose response in IORT.Electronic supplementary materialThe online version of this article (doi:10.1186/s13014-016-0754-z) contains supplementary material, which is available to authorized users.

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“…16 Attempts have been made by several investigators to measure the exit skin dose received during intracavitary APBI treatments. The detectors have included thermoluminescent dosimeters ͑TLDs͒, 9,17,18 radiochromic film, 19 and metal oxide semiconductor field effect transistors. 18,20,21 While all of these detectors are relatively thin and therefore well-suited for surface measurements, they all measure the dose at some distance above the skin.…”

Section: Introductionmentioning

confidence: 99%

“…The detectors have included thermoluminescent dosimeters ͑TLDs͒, 9,17,18 radiochromic film, 19 and metal oxide semiconductor field effect transistors. 18,20,21 While all of these detectors are relatively thin and therefore well-suited for surface measurements, they all measure the dose at some distance above the skin. As demonstrated by Stathakis et al 22 for high energy photon beams, corrections that account for the dose gradient and electronic disequilibrium at the surface must be applied to determine the actual dose at the basal skin layer from measurements made at the surface.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2010

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Purpose: Intracavitary accelerated partial breast irradiation ͑APBI͒ has become a popular treatment for early stage breast cancer in recent years due to its shortened course of treatment and simplified treatment planning compared to traditional external beam breast conservation therapy. However, the exit dose to the skin is a major concern and can be a limiting factor for these treatments. Most treatment planning systems ͑TPSs͒ currently used for high dose-rate ͑HDR͒ 192Ir brachytherapy overestimate the exit skin dose because they assume a homogeneous water medium and do not account for finite patient dimensions. The purpose of this work was to quantify the TPS overestimation of the exit skin dose for a group of patients and several phantom configurations. Methods: The TPS calculated skin dose for 59 HDR 192 Ir APBI patients was compared to the skin dose measured with LiF:Mg,Ti thermoluminescent dosimeters ͑TLDs͒. Additionally, the TPS calculated dose was compared to the TLD measured dose and the Monte Carlo ͑MC͒ calculated dose for eight phantom configurations. Four of the phantom configurations simulated treatment conditions with no scattering material beyond the point of measurement and the other four configurations simulated the homogeneous scattering conditions assumed by the TPS. Since the calibration TLDs for this work were irradiated with 137 Cs and the experimental irradiations were performed with 192 Ir, experiments were performed to determine the intrinsic energy dependence of the TLDs. Correction factors that relate the dose at the point of measurement ͑center of TLD͒ to the dose at the point of interest ͑basal skin layer͒ were also determined and applied for each irradiation geometry. Results: The TLD intrinsic energy dependence for 192 Ir relative to 137 Cs was 1.041Ϯ 1.78%. The TPS overestimated the exit skin dose by an average of 16% for the group of 59 patients studied, and by 9%-15% for the four phantom setups simulating treatment conditions. For the four phantom setups simulating the conditions assumed by the TPS, the TPS calculated dose agreed well with the TLD and MC results ͑within 3% and 1%, respectively͒. The inverse square geometry correction factor ranged from 1.023 to 1.042, and an additional correction factor of 0.978 was applied to account for the lack of charged particle equilibrium in the TLD and basal skin layer. Conclusions: TPS calculations that assume a homogeneous water medium overestimate the exit skin dose for intracavitary APBI treatments. It is important to determine the actual skin dose received during intracavitary APBI to determine the skin dose-response relationship and establish dose limits for optimal skin sparing. This study has demonstrated that TLDs can measure the skin dose with an expanded uncertainty ͑k =2͒ of 5.6% when the proper corrections are applied.

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Evaluation of the surface radiation dose and dose gradient in early stage breast cancer using high-dose-rate brachytherapy MammoSite™ applicator

Cited by 15 publications

References 19 publications

Thermoluminescence dosimetry for skin dose assessment during intraoperative radiotherapy for early breast cancer

Thermoluminescence dosimetry for skin dose assessment during intraoperative radiotherapy for early breast cancer

Present state and issues in IORT Physics

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

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