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Ni J, Gan G, Xu X. Quantitative study on dose distribution of Freiburg flap for keloid high-dose-rate brachytherapy based on MatriXX. J Appl Clin Med Phys 2023; 24:e14118. [PMID: 37593834 PMCID: PMC10476986 DOI: 10.1002/acm2.14118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 04/18/2023] [Accepted: 07/25/2023] [Indexed: 08/19/2023] Open
Abstract
PURPOSE To quantify the dose distribution effect of insufficient scattering conditions in keloid HDR brachytherapy with Freiburg fFlap (FF) applicator. MATERIALS AND METHODS A phantom composed of FF applicator, MatriXX and solid water slices was designed and scanned for treatment planning. Bolus with different thicknesses were covered to offer different scatter conditions. Planar dose distributions were measured by MatriXX. The maximum value (Max), average value (Avg) and γ passing rate (3 mm/3%) were evaluated by the software MyQA Platform. RESULTS The maximum and average doses measured by MatriXX were lower than the calculated values. The difference increased as field size decreased. The Max value, found at 0.86 cm level in the two tube case, was -20.0%, and the avg value was -11.9%. All the γ values were less than 95%. This difference gradually decreased with increasing bolus thickness and the γ values were significantly improved. CONCLUSION MatriXX could be used for dose verification of HDR brachytherapy with an FF applicator. When the FF applicator was applied for keloid, insufficient scattering conditions would cause an insufficient target dose. This difference could be reduced by covering the bolus with different thicknesses on the applicator. The smaller the field, the thicker the bolus required.
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Affiliation(s)
- Jie Ni
- Radiation Therapy CenterThe First Affiliated Hospital of Soochow UniversitySuzhouJiangsu ProvinceChina
| | - Guanghui Gan
- Radiation Therapy CenterThe First Affiliated Hospital of Soochow UniversitySuzhouJiangsu ProvinceChina
| | - Xiaoting Xu
- Radiation Therapy CenterThe First Affiliated Hospital of Soochow UniversitySuzhouJiangsu ProvinceChina
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Multicatheter interstitial brachytherapy versus stereotactic radiotherapy with CyberKnife for accelerated partial breast irradiation: a comparative treatment planning study with respect to dosimetry of organs at risk. Radiol Oncol 2021; 55:229-239. [PMID: 33768766 PMCID: PMC8042824 DOI: 10.2478/raon-2021-0016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 02/02/2021] [Indexed: 01/02/2023] Open
Abstract
Background The aim of the study was to dosimetrically compare multicatheter interstitial brachytherapy (MIBT) and stereotactic radiotherapy with CyberKnife (CK) for accelerated partial breast irradiation (APBI) especially concerning the dose of organs at risk (OAR-s). Patients and methods Treatment plans of thirty-two MIBT and CK patients were compared. The OAR-s included ipsilateral non-target and contralateral breast, ipsilateral and contralateral lung, skin, ribs, and heart for left-sided cases. The fractionation was identical (4 x 6.25 Gy) in both treatment groups. The relative volumes (e.g. V100, V90) receiving a given relative dose (100%, 90%), and the relative doses (e.g. D0.1cm3, D1cm3) delivered to the most exposed small volumes (0.1 cm3, 1 cm3) were calculated from dose-volume histograms. All dose values were related to the prescribed dose (25 Gy). Results Regarding non-target breast CK performed slightly better than MIBT (V100: 0.7% vs. 1.6%, V50: 10.5% vs. 12.9%). The mean dose of the ipsilateral lung was the same for both techniques (4.9%), but doses irradiated to volume of 1 cm3 were lower with MIBT (36.1% vs. 45.4%). Protection of skin and rib was better with MIBT. There were no significant differences between the dose-volume parameters of the heart, but with MIBT, slightly larger volumes were irradiated by 5% dose (V5: 29.9% vs. 21.2%). Contralateral breast and lung received a somewhat higher dose with MIBT (D1cm3: 2.6% vs. 1.8% and 3.6% vs. 2.5%). Conclusions The target volume can be properly irradiated by both techniques with similar dose distributions and high dose conformity. Regarding the dose to the non-target breast, heart, and contralateral organs the CK was superior, but the nearby organs (skin, ribs, ipsilateral lung) received less dose with MIBT. The observed dosimetric differences were small but significant in a few parameters at the examined patient number. More studies are needed to explore whether these dosimetric findings have clinical significance.
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Monte Carlo simulation and dosimetry measurements of an experimental approach for in vitro HDR brachytherapy irradiation. Appl Radiat Isot 2021; 172:109666. [PMID: 33773203 DOI: 10.1016/j.apradiso.2021.109666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 01/09/2021] [Accepted: 02/23/2021] [Indexed: 11/20/2022]
Abstract
Irradiation of tumor cell lines is a useful way to investigate the effects of ionizing radiation on biological molecules. We designed an easy and reproducible approach for in vitro experimental high dose rate brachytherapy, which was simulated by a Monte Carlo code and dosimetrically characterized by experimental methods to evaluate the correspondence between planned doses and doses absorbed by the cells. This approach is an acrylic platform containing T25 tissue culture flasks and multiwell tissue culture plates. It allows nine parallel needles carrying an 192Ir source to irradiate the adherent cells. The whole system composed of the acrylic platform, tissue culture flasks and 192Ir source tracking was simulated by the Monte Carlo N-Particle transport code (MCNPX). Dosimetric measurements were taken by well ionization chamber and radiochromic films. There was a slight difference, averaging from 2% to 7%, between the MCNPX results and film dosimetry results regarding uniform radiation created by the source arrangement. The results showed different values for planned and measured doses in each cell culture plate, which was attributed to the non-equivalent water material used and to the lack of full scattering coming from the top of the platform. This last contribution was different for each tissue culture plate and an individual dose correction factor was calculated. The dose correction factor must be applied to match the planned dose and the actual doses absorbed by the cells. The designed approach is an efficient tool for in vitro brachytherapy experiments for most commercial cell culture plates.
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Boman EL, Satherley TWS, Schleich N, Paterson DB, Greig L, Louwe RJW. The validity of Acuros BV and TG-43 for high-dose-rate brachytherapy superficial mold treatments. Brachytherapy 2017; 16:1280-1288. [PMID: 28967561 DOI: 10.1016/j.brachy.2017.08.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 08/16/2017] [Accepted: 08/18/2017] [Indexed: 12/20/2022]
Abstract
PURPOSE The purpose of this work is to validate the Acuros BV dose calculation algorithm for high-dose-rate (HDR) brachytherapy superficial mold treatments in the absence of full scatter conditions and compare this with TG-43 dose calculations. We also investigate the impact of additional back scatter material (bolus) applied above surface molds to the dose distributions under the mold. METHODS AND MATERIALS The absorbed dose at various depths was compared for simulations performed using either TG-43 or Acuros BV dose calculations. Parameter variations included treatment area, thickness of the bolus, and surface shape (flat or spherical). Film measurements were carried out in a flat phantom. RESULTS Acuros BV calculations and film measurements agreed within 1.5% but were up to 15% lower than TG-43 dose calculations when no bolus was applied above the treatment catheters. The difference in dose at the prescription depth (1 cm below the central catheter) increased with increasing treatment area: 3.3% difference for a 3 × 3.5 cm2 source loading area, 7.4% for 8 × 9 cm2, and 13.4% for 18 × 19 cm2. The dose overestimation of the TG-43 model decreased when bolus was added above the treatment catheters. CONCLUSIONS The TG-43 dosimetry formalism cannot model surface mold treatments in the absence of full scatter conditions within 5% for loading areas larger than approximately 5 × 5 cm2. The TG-43 model results in an overestimation of the delivered dose, which increases with treatment area. This confirms the need for model-based dose calculation algorithms as discussed in TG-186.
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Affiliation(s)
- Eeva L Boman
- Blood & Cancer Centre, Wellington Hospital, Wellington, NZ; Department of Oncology, Tampere University Hospital, Tampere, Finland; Department of Medical Physics, Tampere University Hospital, Tampere, Finland.
| | | | | | | | - Lynne Greig
- Blood & Cancer Centre, Wellington Hospital, Wellington, NZ
| | - Rob J W Louwe
- Blood & Cancer Centre, Wellington Hospital, Wellington, NZ
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Dose comparison between TG-43–based calculations and radiochromic film measurements of the Freiburg flap applicator used for high-dose-rate brachytherapy treatments of skin lesions. Brachytherapy 2017; 16:1065-1072. [DOI: 10.1016/j.brachy.2017.06.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 06/24/2017] [Accepted: 06/26/2017] [Indexed: 11/19/2022]
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Intraoperative high-dose-rate brachytherapy: An American Brachytherapy Society consensus report. Brachytherapy 2017; 16:446-465. [DOI: 10.1016/j.brachy.2017.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/19/2016] [Accepted: 01/02/2017] [Indexed: 11/22/2022]
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Automated construction of an intraoperative high-dose-rate treatment plan library for the Varian brachytherapy treatment planning system. Brachytherapy 2016; 15:531-536. [DOI: 10.1016/j.brachy.2016.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 03/25/2016] [Accepted: 04/05/2016] [Indexed: 11/17/2022]
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Park JM, Kim IH, Ye SJ, Kim K. Evaluation of treatment plans using various treatment techniques for the radiotherapy of cutaneous Kaposi's sarcoma developed on the skin of feet. J Appl Clin Med Phys 2014; 15:4970. [PMID: 25493522 PMCID: PMC5711114 DOI: 10.1120/jacmp.v15i6.4970] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 08/03/2014] [Accepted: 07/28/2014] [Indexed: 11/23/2022] Open
Abstract
The purpose of this study was to investigate the plan qualities of various treatment modalities for the radiotherapy of cutaneous Kaposi's sarcoma developed on the skin of the foot. A total of six virtual targets were generated on the skin of the foot in CT images. Five types of treatment plans were generated using photon beams (PB), electron beams (EB), high‐dose‐rate (HDR) brachytherapy with a Freiburg flap applicator, intensity‐modulated radiation therapy (IMRT), and volumetric‐modulated arc therapy (VMAT) techniques. Plans for each of the six targets (single‐target plans) and also for the combined target consisting of the six single targets combined (multitarget plans) were generated. Dose‐volumetric analysis was performed for the targets and normal tissues. The averaged conformity index (CI) and homogeneity index (HI) values for each single target using PB, EB, HDR, IMRT, and VMAT techniques were 1.97, 2.39, 1.60, 4.60, and 0.80 and 1.05, 1.11, 1.52, 1.04, and 1.04, respectively. For the multitarget, the CI values were 3.99, 5.08, 1.38, 1.95, and 0.84, and the values of HI were 1.10, 1.36, 1.43, 1.06, and 1.04, respectively. The averaged mean doses to normal tissue were 2.5, 2.7, 3.6, 1.7, and 2.9 Gy for single‐target plans, and 21.3, 14.6, 14.2, 14.3, and 13.0 Gy for the multitarget plans, respectively. The VMAT demonstrated dosimetric advantages and better treatment efficiency over other techniques for the radiotherapy of multifocal skin disease of the feet. PACS number: 87.55.dk
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Lee CD. Recent developments and best practice in brachytherapy treatment planning. Br J Radiol 2014; 87:20140146. [PMID: 24734939 PMCID: PMC4453147 DOI: 10.1259/bjr.20140146] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 04/10/2014] [Accepted: 04/14/2014] [Indexed: 12/20/2022] Open
Abstract
Brachytherapy has evolved over many decades, but more recently, there have been significant changes in the way that brachytherapy is used for different treatment sites. This has been due to the development of new, technologically advanced computer planning systems and treatment delivery techniques. Modern, three-dimensional (3D) imaging modalities have been incorporated into treatment planning methods, allowing full 3D dose distributions to be computed. Treatment techniques involving online planning have emerged, allowing dose distributions to be calculated and updated in real time based on the actual clinical situation. In the case of early stage breast cancer treatment, for example, electronic brachytherapy treatment techniques are being used in which the radiation dose is delivered during the same procedure as the surgery. There have also been significant advances in treatment applicator design, which allow the use of modern 3D imaging techniques for planning, and manufacturers have begun to implement new dose calculation algorithms that will correct for applicator shielding and tissue inhomogeneities. This article aims to review the recent developments and best practice in brachytherapy techniques and treatments. It will look at how imaging developments have been incorporated into current brachytherapy treatment and how these developments have played an integral role in the modern brachytherapy era. The planning requirements for different treatments sites are reviewed as well as the future developments of brachytherapy in radiobiology and treatment planning dose calculation.
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Affiliation(s)
- C D Lee
- Physics Department, Clatterbridge Cancer Centre, Bebington, Wirral, UK
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Sharma R, Jursinic PA. In vivomeasurements for high dose rate brachytherapy with optically stimulated luminescent dosimeters. Med Phys 2013; 40:071730. [DOI: 10.1118/1.4811143] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Uniyal S, Sharma S, Naithani U. Dosimetric verification of a high dose rate brachytherapy treatment planning system in homogeneous and heterogeneous media. Phys Med 2013; 29:171-7. [DOI: 10.1016/j.ejmp.2012.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 12/02/2011] [Accepted: 01/17/2012] [Indexed: 10/28/2022] Open
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Perez-Calatayud J, Ballester F, Das RK, Dewerd LA, Ibbott GS, Meigooni AS, Ouhib Z, Rivard MJ, Sloboda RS, Williamson JF. Dose calculation for photon-emitting brachytherapy sources with average energy higher than 50 keV: Report of the AAPM and ESTRO. Med Phys 2012; 39:2904-29. [PMID: 22559663 DOI: 10.1118/1.3703892] [Citation(s) in RCA: 191] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Jose Perez-Calatayud
- Radiotherapy Department, La Fe Polytechnic and University Hospital, Valencia, Spain
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Hyer DE, Sheybani A, Jacobson GM, Kim Y. The dosimetric impact of heterogeneity corrections in high-dose-rate ¹⁹²Ir brachytherapy for cervical cancer: Investigation of both conventional Point-A and volume-optimized plans. Brachytherapy 2012; 11:515-20. [PMID: 22386723 DOI: 10.1016/j.brachy.2012.01.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 12/19/2011] [Accepted: 01/16/2012] [Indexed: 11/18/2022]
Abstract
PURPOSE To evaluate the dosimetric impact of heterogeneity corrections on both conventional and volume-optimized high-dose-rate (HDR) ¹⁹²Ir brachytherapy tandem-and-ovoid treatment plans. METHODS AND MATERIALS Both conventional and volume-optimized treatment plans were retrospectively created using eight unique CT data sets. In the volume-optimized plans, the clinical target volume (CTV) and organs-at-risk (rectum, bladder, and sigmoid) were contoured on the CT data sets by a single physician. For each plan, dose calculations representing homogeneous water medium were performed using the Task Group (TG-43) formalism and dose calculations with heterogeneity corrections were performed using a commercially available treatment planning system. RESULTS For the conventional plans, the change in dose between TG-43 and heterogeneity-corrected calculations was assessed for the following points: Point-A (left and right) and International Commission on Radiation Units and Measurements (ICRU) 38 defined rectum and bladder points. It was found that the dose to the ICRU bladder decreased the most (-2.2±0.9%), whereas ICRU rectum (-1.7±0.8%), Point-A right (-1.1±0.4%), and Point-A left (-1.0±0.3%) also showed decreases with heterogeneity-corrected calculations. For the volume-optimized plans, the change in dose between TG-43 and heterogeneity-corrected calculations was assessed for the following dose-volume histogram parameters: D(90) of the CTV and D(2cc) of the rectum, bladder, and sigmoid. It was found that D(90) of the CTV decreased by -1.9±0.7% and D(2cc) decreased by -2.6±1.4%, -1.0±0.4%, and -2.0±0.6% for the rectum, bladder and sigmoid, respectively, with heterogeneity-corrected calculations. CONCLUSIONS Heterogeneity corrections on high-dose rate plans were found to have only a small dosimetric impact over TG-43-based dose calculations for both conventional Point-A and volume-optimized plans.
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Affiliation(s)
- Daniel E Hyer
- Department of Radiation Oncology, University of Iowa, Iowa City, IA, USA
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Vijande J, Ballester F, Ouhib Z, Granero D, Pujades-Claumarchirant MC, Perez-Calatayud J. Dosimetry comparison between TG-43 and Monte Carlo calculations using the Freiburg flap for skin high-dose-rate brachytherapy. Brachytherapy 2012; 11:528-35. [PMID: 22226080 DOI: 10.1016/j.brachy.2011.11.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 09/27/2011] [Accepted: 11/14/2011] [Indexed: 11/16/2022]
Abstract
PURPOSE The purpose of this work was to evaluate whether the delivered dose to the skin surface and at the prescription depth when using a Freiburg flap applicator is in agreement with the one predicted by the treatment planning system (TPS) using the TG-43 dose-calculation formalism. METHODS AND MATERIALS Monte Carlo (MC) simulations and radiochromic film measurements have been performed to obtain dose distributions with the source located at the center of one of the spheres and between two spheres. Primary and scatter dose contributions were evaluated to understand the role played by the scatter component. A standard treatment plan was generated using MC- and TG-43-based TPS applying the superposition principle. RESULTS The MC model has been validated by performing additional simulations in the same conditions but transforming air and Freiburg flap materials into water to match TG-43 parameters. Both dose distributions differ less than 1%. Scatter defect compared with TG-43 data is up to 15% when the source is located at the center of the sphere and up to 25% when the source is between two spheres. Maximum deviations between TPS- and MC-based distributions are of 5%. CONCLUSIONS The deviations in the TG-43-based dose distributions for a standard treatment plan with respect to the MC dose distribution calculated taking into account the composition and shape of the applicator and the surrounding air are lower than 5%. Therefore, this study supports the validity of the TPS used in clinical practice.
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Affiliation(s)
- Javier Vijande
- Department of Atomic, Molecular, and Nuclear Physics, University of Valencia, Burjassot, Spain.
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Uniyal SC, Naithani UC, Sharma SD, Srivastava AK. Radiochromic film dosimetry of rectal inhomogeneity and applicator attenuation in high dose rate brachytherapy of uterine cervix. J Appl Clin Med Phys 2012; 13:3654. [PMID: 22231217 PMCID: PMC5716133 DOI: 10.1120/jacmp.v13i1.3654] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 09/08/2011] [Accepted: 09/12/2011] [Indexed: 01/08/2023] Open
Abstract
Heterogeneities existing in the patient during treatment are neglected, as the treated subject is considered homogeneous in most of the commercially‐available treatment planning systems (TPSs) used for high dose rate (HDR) brachytherapy. The choice of a suitable dosimeter for experimental dosimetry near the HDR source is crucial, mainly due to existence of steep dose gradients. The present work aimed to assess the effect of rectal air heterogeneity and applicator attenuation in the HDR Ir‐192 brachytherapy treatment of carcinoma uterine cervix by utilizing GAFCHROMIC EBT2 film dosimetry. The dose to rectal walls under the condition of rectal air heterogeneity was measured experimentally using EBT2 film in a rectal phantom, and the measurements were validated by the Monte Carlo (MC) simulations. The applicator attenuation was measured by EBT2 film for a commonly used stainless steel uterine tube in a homogeneous water equivalent phantom. The measured doses were compared with the TPS calculated values. In case of the air cavity, the measured dose at the closest rectal surface was 12.8% less than the TPS calculated value due to lack of back scattering, whereas at the farthest rectal surface, it was higher by 24.5% due to no attenuation. The magnitude of attenuation due to the metal applicator was measured as high as 2% when compared with the TPS calculation. The dose reduction at the nearest rectal surface due to the effect of rectal air has indicated a clinically favorable dose distribution within the rectum, whereas the shielding effect posed by the metallic applicator was found to be less significant. Mutual agreement of the measured doses with the MC calculated dose values confirmed the suitability of EBT2 film for clinical dosimetry in HDR brachytherapy. PACS numbers: 87.53.Bn, 87.53.Jw, 87.56.bg, 87.55.Qr
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Affiliation(s)
- Satish C Uniyal
- Department of Radiology, Himalayan Institute of Medical Sciences, HIHT University, Jolly Grant, Dehradun 248140, India.
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Hira M, Podgorsak MB, Jaggernauth W, Malhotra HK. Measurement of dose perturbation around shielded ovoids in high-dose-rate brachytherapy. Brachytherapy 2011; 10:232-41. [DOI: 10.1016/j.brachy.2010.08.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 07/30/2010] [Accepted: 08/11/2010] [Indexed: 11/17/2022]
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Poon E, Verhaegen F. Development of a scatter correction technique and its application to HDR I192r multicatheter breast brachytherapy. Med Phys 2009; 36:3703-13. [DOI: 10.1118/1.3157105] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Kwan IS, Wilkinson D, Cutajar D, Lerch M, Rosenfeld A, Howie A, Bucci J, Chin Y, Perevertaylo VL. The effect of rectal heterogeneity on wall dose in high dose rate brachytherapy. Med Phys 2009; 36:224-32. [PMID: 19235390 DOI: 10.1118/1.3031111] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
When treating prostate cancer using high dose rate (HDR) brachytherapy, overdosing the rectal wall may lead to post-treatment rectal complications. An area of concern is related to how the rectal wall dose is calculated by treatment planning systems (TPSs). TPSs are used to calculate the dose delivered to the rectal wall, but they assume that the rectum is a water-equivalent homogeneous medium of infinite size and do not consider the effect that an air-filled "empty" rectal cavity would have on the dose absorbed along the rectal wall. The aim of this research is to quantify the effect that an air cavity has on the rectal wall dose, as its presence changes the backscatter conditions in the region. The MO Skin and RADFET dosimeters proved capable of measuring absolute dose with increasing distance from the HDR Ir-192 brachytherapy source. However, the anterior rectal wall doses measured by the MOSkin and RADFET in an empty rectal cavity were 14.7 +/- 0.2% and 13.7 +/- 0.6% lower than the dose measured in a homogeneous rectal phantom. Monte Carlo simulations corroborated the experimentally obtained results, reporting a -13.2 +/- 0.6% difference. The dose measured at the posterior wall of an empty rectal cavity was between 22% and 26% greater than the dose measured in a full rectal cavity. The heterogeneity of the rectal volume appears to have a significant effect on the rectal dose when compared to calculated rectal dose.
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Affiliation(s)
- I S Kwan
- Centre of Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales 2522, Australia
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Oh M, Wang Z, Malhotra HK, Jaggernauth W, Podgorsak MB. Impact of Surface Curvature on Dose Delivery in Intraoperative High-Dose-Rate Brachytherapy. Med Dosim 2009; 34:63-74. [DOI: 10.1016/j.meddos.2008.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 05/06/2008] [Accepted: 05/14/2008] [Indexed: 11/27/2022]
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Wojcicka JB, Lasher DE, McAfee SS, Fortier GA. Dosimetric comparison of three different treatment techniques in extensive scalp lesion irradiation. Radiother Oncol 2008; 91:255-60. [PMID: 18954915 DOI: 10.1016/j.radonc.2008.09.022] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 08/29/2008] [Accepted: 09/07/2008] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND PURPOSE This study compared lateral photon/electron plan (3DCRT), intensity modulated radiation therapy (IMRT) plan, and high dose rate (HDR) brachytherapy plan for total scalp irradiation. MATERIALS AND METHODS The techniques were planned on a patient with squamous cell carcinoma of the scalp for a prescribed dose of 60 Gy. Conformity indexes and dose volume histograms were used for the comparison. RESULTS Clinical target volume coverage factors for 3DCRT, IMRT, and HDR were 0.976, 0.998, and 0.967, and Conformation Numbers were 0.532, 0.713, and 0.761, respectively. The dose gradient across the target was 59-136%, 91-129%, and 58-242% for 3DCRT, IMRT, and HDR techniques, respectively. The 3DCRT and IMRT techniques produced low optical structure doses. 3DCRT produced hotspots in the brain, while IMRT produced brain sparing. HDR produced the highest integral doses to the brain and optical structures. CONCLUSIONS IMRT provided the best target dose homogeneity and coverage, and delivered clinically acceptable doses to normal structures. HDR produced the most conformal plan, but the total dose delivered is limited by doses to the brain and eyes. HDR is a clinically feasible alternative for less extensive lesions, lower prescription doses, and for patients who cannot lie on the treatment table.
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Affiliation(s)
- Jadwiga B Wojcicka
- Department of Radiation Oncology, York Cancer Center, York, PA 17403, USA.
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Melchert C, Kohr P, Schmidt R. Calculation of dose decrease in a finite phantom of a Ir192 point source. Med Phys 2007; 34:3943-50. [DOI: 10.1118/1.2775664] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Retrospective analysis of dose delivery in intra-operative high dose rate brachytherapy. Radiol Oncol 2007. [DOI: 10.2478/v10019-007-0030-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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