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Title: SU-F-T-314: Estimation of Dose Distributions with Different Types of Breast Implants in Various Radiation Treatment Techniques for Breast Cancer

Abstract

Purpose: This study investigates the effects of different kinds and designs of commercialized breast implants on the dose distributions in breast cancer radiotherapy under a variety of conditions. Methods: The dose for the clinical conventional tangential irradiation, Intensity Modulated Radiation Therapy (IMRT), volumetric modulated arc therapy (VMAT) breast plans was measured using radiochromic films and stimulated luminescence dosimeter (OSLD). The radiochromic film was used as an integrating dosimeter, while the OSLDs were used for real-time dosimetry to isolate the contribution of dose from individual segment. The films were placed at various slices in the Rando phantom and between the body and breast surface OSLDs were used to measure skin dose at 18 positions spaced on the two (right/left) breast. The implant breast was placed on the left side and the phantom breast was remained on the right side. Each treatment technique was performed on different size of the breasts and different shape of the breast implant. The PTV dose was prescribed 50.4 Gy and V47.88≥95%. Results: In different shapes of the breast implant, because of the shadow formed extensive around the breast implant, dose variation was relatively higher that of prescribed dose. As the PTV was delineated on the wholemore » breast, maximum 5% dose error and average 3% difference was observed averagely. VMAT techniques largely decrease the contiguous hot spot in the skin by an average of 25% compared with IMRT. The both IMRT and VMAT techniques resulted in lower doses to normal critical structures than tangential plans for nearly all dose analyzation. Conclusion: Compared to the other technique, IMRT reduced radiation dose exposure to normal tissues and maintained reasonable target homogeneity and for the same target coverage, VMAT can reduce the skin dose in all the regions of the body.« less

Authors:
; ;  [1];  [2];  [1];  [2];  [2]; ; ;  [3]
  1. Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of)
  2. (Korea, Republic of)
  3. Department of Radiation Oncology, Gangnam Severance Hospital, Seoul (Korea, Republic of)
Publication Date:
OSTI Identifier:
22648920
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; ANIMAL TISSUES; HOT SPOTS; IMPLANTS; MAMMARY GLANDS; NEOPLASMS; RADIATION DOSE DISTRIBUTIONS; RADIOTHERAPY; SKIN

Citation Formats

Lee, M, Lee, S, Suh, T, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Jung, J, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Department of Radiation Oncology, College of Medicine, Soonchunhyang University Bucheon Hospital, Bucheon, Kim, S, Cho, Y, and Lee, I. SU-F-T-314: Estimation of Dose Distributions with Different Types of Breast Implants in Various Radiation Treatment Techniques for Breast Cancer. United States: N. p., 2016. Web. doi:10.1118/1.4956499.
Lee, M, Lee, S, Suh, T, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Jung, J, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Department of Radiation Oncology, College of Medicine, Soonchunhyang University Bucheon Hospital, Bucheon, Kim, S, Cho, Y, & Lee, I. SU-F-T-314: Estimation of Dose Distributions with Different Types of Breast Implants in Various Radiation Treatment Techniques for Breast Cancer. United States. doi:10.1118/1.4956499.
Lee, M, Lee, S, Suh, T, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Jung, J, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Department of Radiation Oncology, College of Medicine, Soonchunhyang University Bucheon Hospital, Bucheon, Kim, S, Cho, Y, and Lee, I. 2016. "SU-F-T-314: Estimation of Dose Distributions with Different Types of Breast Implants in Various Radiation Treatment Techniques for Breast Cancer". United States. doi:10.1118/1.4956499.
@article{osti_22648920,
title = {SU-F-T-314: Estimation of Dose Distributions with Different Types of Breast Implants in Various Radiation Treatment Techniques for Breast Cancer},
author = {Lee, M and Lee, S and Suh, T and Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul and Jung, J and Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul and Department of Radiation Oncology, College of Medicine, Soonchunhyang University Bucheon Hospital, Bucheon and Kim, S and Cho, Y and Lee, I},
abstractNote = {Purpose: This study investigates the effects of different kinds and designs of commercialized breast implants on the dose distributions in breast cancer radiotherapy under a variety of conditions. Methods: The dose for the clinical conventional tangential irradiation, Intensity Modulated Radiation Therapy (IMRT), volumetric modulated arc therapy (VMAT) breast plans was measured using radiochromic films and stimulated luminescence dosimeter (OSLD). The radiochromic film was used as an integrating dosimeter, while the OSLDs were used for real-time dosimetry to isolate the contribution of dose from individual segment. The films were placed at various slices in the Rando phantom and between the body and breast surface OSLDs were used to measure skin dose at 18 positions spaced on the two (right/left) breast. The implant breast was placed on the left side and the phantom breast was remained on the right side. Each treatment technique was performed on different size of the breasts and different shape of the breast implant. The PTV dose was prescribed 50.4 Gy and V47.88≥95%. Results: In different shapes of the breast implant, because of the shadow formed extensive around the breast implant, dose variation was relatively higher that of prescribed dose. As the PTV was delineated on the whole breast, maximum 5% dose error and average 3% difference was observed averagely. VMAT techniques largely decrease the contiguous hot spot in the skin by an average of 25% compared with IMRT. The both IMRT and VMAT techniques resulted in lower doses to normal critical structures than tangential plans for nearly all dose analyzation. Conclusion: Compared to the other technique, IMRT reduced radiation dose exposure to normal tissues and maintained reasonable target homogeneity and for the same target coverage, VMAT can reduce the skin dose in all the regions of the body.},
doi = {10.1118/1.4956499},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = 2016,
month = 6
}
  • Purpose: Contemporary radiotherapy treatment techniques, such as intensity-modulated radiation therapy and volumetric modulated arc therapy, could increase the radiation-induced malignancies because of the increased beam-on time, i.e., number of monitor units needed to deliver the same dose to the target and the larger volume irradiated with low doses. In this study, whole-body dose distributions from typical radiotherapy patient plans using different treatment techniques and therapy machines were measured using the same measurement setup and irradiation intention. Methods: Individually calibrated thermoluminescent dosimeters were used to measure absorbed dose in an anthropomorphic phantom at 184 locations. The dose distributions from 6 MVmore » beams were compared in terms of treatment technique (3D-conformal, intensity-modulated radiation therapy, volumetric modulated arc therapy, helical TomoTherapy, stereotactic radiotherapy, hard wedges, and flattening filter-free radiotherapy) and therapy machine (Elekta, Siemens and Varian linear accelerators, Accuray CyberKnife and TomoTherapy). Results: Close to the target, the doses from intensity-modulated treatments (including flattening filter-free) were below the dose from a static treatment plan, whereas the CyberKnife showed a larger dose by a factor of two. Far away from the treatment field, the dose from intensity-modulated treatments showed an increase in dose from stray radiation of about 50% compared to the 3D-conformal treatment. For the flattening filter-free photon beams, the dose from stray radiation far away from the target was slightly lower than the dose from a static treatment. The CyberKnife irradiation and the treatment using hard wedges increased the dose from stray radiation by nearly a factor of three compared to the 3D-conformal treatment. Conclusions: This study showed that the dose outside of the treated volume is influenced by several sources. Therefore, when comparing different treatment techniques, the dose ratios vary with distance to the isocenter. The effective dose outside the treated volume of intensity-modulated treatments with or without flattening filter was 10%-30% larger when compared to 3D-conformal radiotherapy. This dose increase is much lower than the monitor unit scaled effective dose from a static treatment.« less
  • Purpose: In this study, dosimetric comparison of field in field (FIF) and intensity modulated radiation therapy (IMRT) techniques used for treatment of whole breast radiotherapy (WBRT) were made. The dosimetric accuracy of treatment planning system (TPS) for Anisotropic Analytical Algorithm (AAA) and Acuros XB (AXB) algorithms in predicting PTV and OAR doses was also investigated. Methods: Two different treatment planning techniques of left-sided breast cancer were generated for rando phantom. FIF and IMRT plans were compared for doses in PTV and OAR volumes including ipsilateral lung, heart, left ascending coronary artery, contralateral lung and the contralateral breast. PTV and OARsmore » doses and homogeneity and conformality indexes were compared between two techniques. The accuracy of TPS dose calculation algorithms was tested by comparing PTV and OAR doses measured by thermoluminescent dosimetry with the dose calculated by the TPS using AAA and AXB for both techniques. Results: IMRT plans had better conformality and homogeneity indexes than FIF technique and it spared OARs better than FIF. While both algorithms overestimated PTV doses they underestimated all OAR doses. For IMRT plan, PTV doses, overestimation up to 2.5 % was seen with AAA algorithm but it decreased to 1.8 % when AXB algorithm was used. Based on the results of the anthropomorphic measurements for OAR doses, underestimation greater than 7 % is possible by the AAA. The results from the AXB are much better than the AAA algorithm. However, underestimations of 4.8 % were found in some of the points even for AXB. For FIF plan, similar trend was seen for PTV and OARs doses in both algorithm. Conclusion: When using the Eclipse TPS for breast cancer, AXB the should be used instead of the AAA algorithm, bearing in mind that the AXB may still underestimate all OAR doses.« less
  • Purpose: Whole breast irradiation with deep-inspiration breath-hold (DIBH) technique among left-sided breast cancer patients significantly reduces cardiac irradiation; however, a potential disadvantage is increased incidental irradiation of the contralateral breast. Methods and Materials: Contralateral breast dose (CBD) was calculated by comparing 400 treatment plans of 200 left-sided breast cancer patients whose tangential fields had been planned on gated and nongated CT data sets. Various anatomic and field parameters were analyzed for their impact on CBD. For a subgroup of patients (aged {<=}45 years) second cancer risk in the contralateral breast (CB) was modeled by applying the linear quadratic model, compoundmore » models, and compound models considering dose-volume information (DVH). Results: The mean CBD was significantly higher in DIBH with 0.69 Gy compared with 0.65 Gy in normal breathing (P=.01). The greatest impact on CBD was due to a shift of the inner field margin toward the CB in DIBH (mean 0.4 cm; range, 0-2), followed by field size in magnitude. Calculation with different risk models for CBC revealed values of excess relative risk/Gy ranging from 0.48-0.65 vs 0.46-0.61 for DIBH vs normal breathing, respectively. Conclusion: Contralateral breast dose, although within a low dose range, was mildly but significantly increased in 200 treatment plans generated under gated conditions, predominately due to a shift in the medial field margin. Risk modeling for CBC among women aged {<=}45 years also pointed to a higher risk when comparing DIBH with normal breathing. This risk, however, was substantially lower in the model considering DVH information. We think that clinical decisions should not be affected by this small increase in CBD with DIBH because DIBH is effective in reducing the dose to the heart in all patients.« less
  • Purpose: Estimates of secondary cancer risk after radiotherapy are becoming more important for comparative treatment planning. Modern treatment planning systems provide accurate three-dimensional dose distributions for each individual patient. These data open up new possibilities for more precise estimates of secondary cancer incidence rates in the irradiated organs. We report a new method to estimate organ-specific radiation-induced cancer incidence rates. The concept of an organ equivalent dose (OED) for radiation-induced cancer assumes that any two dose distributions in an organ are equivalent if they cause the same radiation-induced cancer incidence. Methods and Materials: The two operational parameters of the OEDmore » concept are the organ-specific cancer incidence rate at low doses, which is taken from the data of the atomic bomb survivors, and cell sterilization at higher doses. The effect of cell sterilization in various organs was estimated by analyzing the secondary cancer incidence data of patients with Hodgkin's disease who were treated with radiotherapy in between 1962 and 1993. The radiotherapy plans used at the time the patients had been treated were reconstructed on a fully segmented whole body CT scan. The dose distributions were calculated in individual organs for which cancer incidence data were available. The model parameter that described cell sterilization was obtained by analyzing the dose and cancer incidence rates for the individual organs. Results: We found organ-specific cell radiosensitivities that varied from 0.017 for the mouth and pharynx up to 1.592 for the bladder. Using the two model parameters (organ-specific cancer incidence rate and the parameter characterizing cell sterilization), the OED concept can be applied to any three-dimensional dose distribution to analyze cancer incidence. Conclusion: We believe that the concept of OED presented in this investigation represents a first step in assessing the potential risk of secondary cancer induction after the clinical application of radiotherapy.« less
  • In breast cancer radiotherapy, the internal mammary lymphatic chain is treated in the target volume in a group of patients with high-risk criteria. Because of the variability of the anatomic region and structures in the irradiation field, there are a number of different techniques in breast radiotherapy. While irradiating the target volume, we also consider minimizing the dose to critical structures such as heart, lung, and contralateral breast tissue. In this study, we evaluated the dose distribution of different radiotherapy techniques in patients with left-sided breast cancer who had breast-conserving surgery. A three-dimensional computerized planning system (3DCPS) was used formore » each patient to compare wide-field, oblique photon-electron, and perpendicular photon-electron techniques in terms of dose homogeneities in the target volume; the doses received by the contralateral breast, heart, and lung; and the coverage of the internal mammary chain. Data from 3DCPS were controlled by the Rando-phantom and thermoluminescence dosimetry. Critical structures were irradiated with acceptable dose percentages in addition to the internal mammary chain with both wide-field and photon-electron techniques. We detected more frequent hot spots in the oblique photon-electron technique than in the other techniques, and this situation necessitated changing the junctions. The wide-field technique was easy to perform and exposed less radiation dose to the heart than photon-electron techniques. In conclusion, we suggest the use of the wide-field technique in breast irradiation when the internal mammary area is in the target volume.« less