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Dosimetric and Radiobiological Plan Evaluation Parameters for Fractionated High-Dose Rate GYN Brachytherapy
Title
Dosimetric and Radiobiological Plan Evaluation Parameters for Fractionated High-Dose Rate GYN Brachytherapy.
Creator
Shojaei, Marjan, Pella, Silvia, Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description
Intracavitary high-dose-rate brachytherapy (HDRBT) is a treatment option for endometrial cancer, depending on the cancer stage. Because of the steep high dose gradient of HDRBT, very small differences in the treatment plans, surrounding organ’s anatomy, or procedures during the treatment could potentially cause significant dose variation to the tumor, as well as organs at risks (OAR) nearby the treatment area, which could result in unwanted radiobiological side effects. In this retrospective...
Show moreIntracavitary high-dose-rate brachytherapy (HDRBT) is a treatment option for endometrial cancer, depending on the cancer stage. Because of the steep high dose gradient of HDRBT, very small differences in the treatment plans, surrounding organ’s anatomy, or procedures during the treatment could potentially cause significant dose variation to the tumor, as well as organs at risks (OAR) nearby the treatment area, which could result in unwanted radiobiological side effects. In this retrospective study, the radiobiological plan evaluation parameters Equivalent Uniform Dose (EUD), Normal Tissue Complication Probability (NTCP) are used as assessment tools to evaluate HDRBT plans. Furthermore, gynecological applicator position in the coordinate system, and possible dose variations to the tumor and critical organs from the initial fraction in comparison with subsequent fractions over the entire multi fractionated treatment are studied. The evaluations were performed for 118 HDR treatment plans for 30 patients by registration of the subsequent treatment plans into the initial CT-image guided plan. Dose fractionation regimens varied from 4Gy to 7Gy per fraction, 1 or 2 fractions per week, depending on the cancer stage. Our results demonstrate no significant radiobiological impacts on organs at risks (OAR). In addition, the results of the applicator positions’ study indicate that improvement of immobilization and localization devices are recommended.
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Date Issued
2018
PURL
http://purl.flvc.org/fau/fd/FA00013144
Subject Headings
Brachytherapy, Radiobiology, Radiation dosimetry--Evaluation
Format
Document (PDF)
A Dosimetric Comparison of 3D-CRT, IMRT, and SAVI HDR via NTCP/TCP and DVH Analysis of Critical Organs for Breast Cancer
Title
A Dosimetric Comparison of 3D-CRT, IMRT, and SAVI HDR via NTCP/TCP and DVH Analysis of Critical Organs for Breast Cancer.
Creator
Wisnoskie, Sarah, Pella, Silvia, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description
Accelerated Partial Breast Irradiation (APBI) is a common treatment of breast cancer with many modalities including 3D Conformal Radiation Therapy (3D-CRT), Intensity Modulated Radiation Therapy (IMRT), and High Dose Rate Brachytherapy (HDR). In this research, a retrospective analysis of patient’s data was performed to analyze the NTCP/TCP (Normal Tissue Complication Probability/Tumor Control Probability) and Dose Volume Histogram (DVH) parameters for HDR with SAVI, 3D, and IMRT and compare...
Show moreAccelerated Partial Breast Irradiation (APBI) is a common treatment of breast cancer with many modalities including 3D Conformal Radiation Therapy (3D-CRT), Intensity Modulated Radiation Therapy (IMRT), and High Dose Rate Brachytherapy (HDR). In this research, a retrospective analysis of patient’s data was performed to analyze the NTCP/TCP (Normal Tissue Complication Probability/Tumor Control Probability) and Dose Volume Histogram (DVH) parameters for HDR with SAVI, 3D, and IMRT and compare them focusing on critical organs such as the heart, ipsilateral lung, chest wall, ribs, and skin. TCP was 90.275%, 55.948%, and 53.369% for HDR, 3D, and IMRT respectively. The ribs were the most sensitive critical organ for all 3 modalities with a mean NTCP of 8%, 15%, and 8% for HDR, 3D, and IMRT respectively. DVH analysis showed HDR spares critical organs more than EBRT except for 2 patients receiving high doses to the ribs and chest wall.
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Date Issued
2019
PURL
http://purl.flvc.org/fau/fd/FA00013281
Subject Headings
Radiation dosimetry--Evaluation, Breast--Cancer--Treatment, Organs, Tissues--Effect of radiation on
Format
Document (PDF)
CONSISTENCY OF CT NUMBER AND ELECTRON DENSITY IN TREATMENT PLANNING SYSTEM VERSUS CT SCANNER, AND DOSIMETRIC CONSEQUENCES
Title
CONSISTENCY OF CT NUMBER AND ELECTRON DENSITY IN TREATMENT PLANNING SYSTEM VERSUS CT SCANNER, AND DOSIMETRIC CONSEQUENCES.
Creator
Hana, Evan Makdasy, Pella, Silvia, Leventouri, Theodora, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description
The Computer Tomography (CT) scanned images are very important for the Treatment Planning System (TPS) to provide the electron density of the different types of tissues that the radiation penetrates in the path to the tumor to be treated. This electron density is converted to an attenuation coefficient, which varies with tissue for each structure and even varies by the tissue volume. The purpose of this research is to evaluate the CT numbers, and convert them into relative electron densities....
Show moreThe Computer Tomography (CT) scanned images are very important for the Treatment Planning System (TPS) to provide the electron density of the different types of tissues that the radiation penetrates in the path to the tumor to be treated. This electron density is converted to an attenuation coefficient, which varies with tissue for each structure and even varies by the tissue volume. The purpose of this research is to evaluate the CT numbers, and convert them into relative electron densities. Twenty-five patients’ data and CT numbers were evaluated in the CT scanner and in Eclipse and were converted into relative electron density and compared with each other. The differences between the relative electron density in the Eclipse was found to be from 0 up to 6% between tissue equivalent materials, the final result for all equivalent tissue materials was about 2%. For the patients’ data, the percentage difference of CT number versus electron density was found to be high for high relative electron density organs, namely the final average result for the spine was 8%, less for pelvis, and less for rib while for the other organs it was even less. The very lowest was 0.3% compared with 1% which is acceptable for clinical standards.
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Date Issued
2019
PURL
http://purl.flvc.org/fau/fd/FA00013315
Subject Headings
Tomography, X-Ray Computed, Electron density, Radiation dosimetry--Evaluation, Tomography Scanners, X-Ray Computed
Format
Document (PDF)