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Michael F Mcnittgray - One of the best experts on this subject based on the ideXlab platform.
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aapm rsna physics tutorial for residents topics in ct Radiation Dose in ct
Radiographics, 2002Co-Authors: Michael F McnittgrayAbstract:This article describes basic Radiation Dose concepts as well as those specifically developed to describe the Radiation Dose from computed tomography (CT). Basic concepts of Radiation Dose are reviewed, including exposure, absorbed Dose, and Effective Dose. Radiation Dose from CT demonstrates variations within the scan plane and along the z axis because of its unique geometry and usage. Several CT-specific Dose descriptors have been developed: the Multiple Scan Average Dose descriptor, the Computed Tomography Dose Index (CTDI) and its variations (CTDI100, CTDIw, CTDIvol), and the Dose-length product. Factors that affect Radiation Dose from CT include the beam energy, tube current‐time product, pitch, collimation, patient size, and Dose reduction options. Methods of reducing the Radiation Dose to a patient from CT include reducing the milliampere-seconds value, increasing the pitch, varying the milliampere-seconds value according to patient size, and reducing the beam energy. The Effective Dose from CT can be estimated by using Monte Carlo methods to simulate CT of a mathematical patient model, by estimating the energy imparted to the body region being scanned, or by using conversion factors for general anatomic regions. Issues related to Radiation Dose from CT are being addressed by the Society for Pediatric Radiology, the American Association of Physicists in Medicine, the American College of Radiology, and the Center for Devices and Radiological Health of the Food and Drug Administration. © RSNA, 2002
Phd Michael F Mcnitt-gray - One of the best experts on this subject based on the ideXlab platform.
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IMAGING & THERAPEUTIC TECHNOLOGY AAPM/RSNA Physics Tutorial for Residents: Topics in CT Radiation Dose in CT 1
2020Co-Authors: Phd Michael F Mcnitt-grayAbstract:This article describes basic Radiation Dose concepts as well as those specifically developed to describe the Radiation Dose from computed tomography (CT). Basic concepts of Radiation Dose are reviewed, including exposure, absorbed Dose, and Effective Dose. Radiation Dose from CT demonstrates variations within the scan plane and along the z axis because of its unique geometry and usage. Several CT-specific Dose descriptors have been developed: the Multiple Scan Average Dose descriptor, the Computed Tomography Dose Index (CTDI) and its variations (CTDI 100 , CTDI w , CTDI vol ), and the Dose-length product. Factors that affect Radiation Dose from CT include the beam energy, tube current-time product, pitch, collimation, patient size, and Dose reduction options. Methods of reducing the Radiation Dose to a patient from CT include reducing the milliampere-seconds value, increasing the pitch, varying the milliampere-seconds value according to patient size, and reducing the beam energy. The Effective Dose from CT can be estimated by using Monte Carlo methods to simulate CT of a mathematical patient model, by estimating the energy imparted to the body region being scanned, or by using conversion factors for general anatomic regions. Issues related to Radiation Dose from CT are being addresse
Naoaki Kohno - One of the best experts on this subject based on the ideXlab platform.
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high biologically Effective Dose Radiation therapy using brachytherapy in combination with external beam radiotherapy for high risk prostate cancer
Journal of Contemporary Brachytherapy, 2017Co-Authors: Keisei Okamoto, Akinori Wada, Naoaki KohnoAbstract:Purpose To evaluate the outcomes of high-risk prostate cancer patients treated with biologically Effective Dose (BED) ≥ 220 Gy of high-Dose radiotherapy, using low-Dose-rate (LDR) brachytherapy in combination with external beam radiotherapy (EBRT) and short-term androgen deprivation therapy (ADT). Material and methods From 2005 to 2013, a total of 143 patients with high-risk prostate cancer were treated by radiotherapy of BED ≥ 220 Gy with a combination of LDR brachytherapy, EBRT, and androgen deprivation therapy (ADT). The high-risk patients in the present study included both high-risk and very high-risk prostate cancer. The number of high-risk features were: 60 patients with 1 high-risk factor (42%), 61 patients with 2 high-risk factors (43%), and 22 patients with 3 high-risk factors (15%) including five N1 disease. External beam radiotherapy fields included prostate and seminal vesicles only or whole pelvis depending on the extension of the disease. Biochemical failure was defined by the Phoenix definition. Results Six patients developed biochemical failure, thus providing a 5-year actual biochemical failure-free survival (BFFS) rate of 95.2%. Biochemical failure was observed exclusively in cases with distant metastasis in the present study. All six patients with biochemical relapse had clinical failure due to bone metastasis, thus yielding a 5-year freedom from clinical failure (FFCF) rate of 93.0%. None of the cases with N1 disease experienced biochemical failure. We observed four deaths, including one death from prostate cancer, therefore yielding a cause-specific survival (CSS) rate of 97.2%, and an overall survival (OS) rate of 95.5%. Conclusions High-Dose (BED ≥ 220 Gy) radiotherapy by LDR in combination with EBRT has shown an excellent outcome on BFFS in high-risk and very high-risk cancer, although causal relationship between BED and BFFS remain to be explained further.
Keisei Okamoto - One of the best experts on this subject based on the ideXlab platform.
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high biologically Effective Dose Radiation therapy using brachytherapy in combination with external beam radiotherapy for high risk prostate cancer
Journal of Contemporary Brachytherapy, 2017Co-Authors: Keisei Okamoto, Akinori Wada, Naoaki KohnoAbstract:Purpose To evaluate the outcomes of high-risk prostate cancer patients treated with biologically Effective Dose (BED) ≥ 220 Gy of high-Dose radiotherapy, using low-Dose-rate (LDR) brachytherapy in combination with external beam radiotherapy (EBRT) and short-term androgen deprivation therapy (ADT). Material and methods From 2005 to 2013, a total of 143 patients with high-risk prostate cancer were treated by radiotherapy of BED ≥ 220 Gy with a combination of LDR brachytherapy, EBRT, and androgen deprivation therapy (ADT). The high-risk patients in the present study included both high-risk and very high-risk prostate cancer. The number of high-risk features were: 60 patients with 1 high-risk factor (42%), 61 patients with 2 high-risk factors (43%), and 22 patients with 3 high-risk factors (15%) including five N1 disease. External beam radiotherapy fields included prostate and seminal vesicles only or whole pelvis depending on the extension of the disease. Biochemical failure was defined by the Phoenix definition. Results Six patients developed biochemical failure, thus providing a 5-year actual biochemical failure-free survival (BFFS) rate of 95.2%. Biochemical failure was observed exclusively in cases with distant metastasis in the present study. All six patients with biochemical relapse had clinical failure due to bone metastasis, thus yielding a 5-year freedom from clinical failure (FFCF) rate of 93.0%. None of the cases with N1 disease experienced biochemical failure. We observed four deaths, including one death from prostate cancer, therefore yielding a cause-specific survival (CSS) rate of 97.2%, and an overall survival (OS) rate of 95.5%. Conclusions High-Dose (BED ≥ 220 Gy) radiotherapy by LDR in combination with EBRT has shown an excellent outcome on BFFS in high-risk and very high-risk cancer, although causal relationship between BED and BFFS remain to be explained further.
Akinori Wada - One of the best experts on this subject based on the ideXlab platform.
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high biologically Effective Dose Radiation therapy using brachytherapy in combination with external beam radiotherapy for high risk prostate cancer
Journal of Contemporary Brachytherapy, 2017Co-Authors: Keisei Okamoto, Akinori Wada, Naoaki KohnoAbstract:Purpose To evaluate the outcomes of high-risk prostate cancer patients treated with biologically Effective Dose (BED) ≥ 220 Gy of high-Dose radiotherapy, using low-Dose-rate (LDR) brachytherapy in combination with external beam radiotherapy (EBRT) and short-term androgen deprivation therapy (ADT). Material and methods From 2005 to 2013, a total of 143 patients with high-risk prostate cancer were treated by radiotherapy of BED ≥ 220 Gy with a combination of LDR brachytherapy, EBRT, and androgen deprivation therapy (ADT). The high-risk patients in the present study included both high-risk and very high-risk prostate cancer. The number of high-risk features were: 60 patients with 1 high-risk factor (42%), 61 patients with 2 high-risk factors (43%), and 22 patients with 3 high-risk factors (15%) including five N1 disease. External beam radiotherapy fields included prostate and seminal vesicles only or whole pelvis depending on the extension of the disease. Biochemical failure was defined by the Phoenix definition. Results Six patients developed biochemical failure, thus providing a 5-year actual biochemical failure-free survival (BFFS) rate of 95.2%. Biochemical failure was observed exclusively in cases with distant metastasis in the present study. All six patients with biochemical relapse had clinical failure due to bone metastasis, thus yielding a 5-year freedom from clinical failure (FFCF) rate of 93.0%. None of the cases with N1 disease experienced biochemical failure. We observed four deaths, including one death from prostate cancer, therefore yielding a cause-specific survival (CSS) rate of 97.2%, and an overall survival (OS) rate of 95.5%. Conclusions High-Dose (BED ≥ 220 Gy) radiotherapy by LDR in combination with EBRT has shown an excellent outcome on BFFS in high-risk and very high-risk cancer, although causal relationship between BED and BFFS remain to be explained further.