Author: Ingrid Isabel Valencia Lozano
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
During a radiotherapy treatment, skin of the patient is always exposed to the radiation; as a consequence late effects can be appear. Therefore, dose values in this region may be of interest for clinical evaluation and investigation of those undesirable effects. However, surface dose is not intuitive and is difficult to measure and calculate; the parameters, which modify it are not always the same and each one are dependent to the others. The aim of this project is to quantify absorbed dose in the build-up region and near to the skin approximately between 0 mm - 1 mm using two methods. One of them, an analytical calculation using Monte Carlo simulations; and the other an experimental approach using an extrapolation chamber. Monte Carlo simulations are performed with the PENELOPE package of subroutines for 6MV and 15MV photon beams. Experimental setup consists in the use of an extrapolation chamber (PTW model 23392), considered the most suitable instrument to measure absorbed dose in the build-up region, but its not commonly available in the hospitals because its use is not practical. The chamber was adapted for its use in clinical environments in a previous work, then for this work the measurement process is easier and results with high level of accuracy can be obtained. In this way, EC (extrapolation chamber) measurements served as the gold standard in our study to validate the Monte Carlo simulations and also with results reported by previous studies. As a result, we found that simulation outcomes are in good agreement with experimental data.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 36
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Book Description
We have successfully developed a practical approach to predicting the location of skin surface dose at potential biopsy sites that receive 1 cGy and 10 cGy, respectively, in support of in vivo biologic dosimetry in humans. This represents a significant technical challenge as the sites lie on the patient surface out side the radiation fields. The PEREGRINE Monte Carlo simulation system was used to model radiation dose delivery and TLDs were used for validation on a phantom and confirmation during patient treatment. In the developmental studies the Monte Carlo simulations consistently underestimated the dose at the biopsy site by approximately 15% for a realistic treatment configuration, most likely due to lack of detail in the simulation of the linear accelerator outside the main beam line. Using a single, thickness-independent correction factor for the clinical calculations, the average of 36 measurements for the predicted 1 cGy point was 0.985 cGy (standard deviation: 0.110 cGy) despite patient breathing motion and other real world challenges. Since the 10 cGy point is situated in the region of high dose gradient at the edge of the field, patient motion had a greater effect and the six measured points averaged 5.90 cGy (standard deviation: 1.01 cGy), a difference that is equivalent to approximately a 6 mm shift on the patient's surface.
Author: International Atomic Energy Agency
Publisher:
ISBN:
Category : Medical
Languages : en
Pages : 260
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Book Description
This Code of Practice, which has also been endorsed by WHO, PAHO and ESTRO, fulfils the need for a systematic and internationally unified approach to the calibration of ionization chambers in terms of absorbed dose to water and to the use of these detectors in determining the absorbed dose to water for the radiation beams used in radiotherapy. It provides a methodology for the determination of absorbed dose to water in the low, medium and high energy photon beams, electron beams, proton beams and heavy ion beams used for external radiation therapy.
Author: International Commission on Radiation Units and Measurements
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 40
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Book Description
Author: Vinzenz Brendler
Publisher:
ISBN:
Category : Ion bombardment
Languages : en
Pages : 117
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Book Description
Author: Katia Parodi
Publisher:
ISBN:
Category :
Languages : en
Pages : 117
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Book Description
Author: International Atomic Energy Agency
Publisher:
ISBN: 9789201006103
Category : Calibration standards
Languages : en
Pages : 0
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Book Description
Author: Michael C. Joiner
Publisher: CRC Press
ISBN: 0429955391
Category : Medical
Languages : en
Pages : 711
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Book Description
Basic Clinical Radiobiology is a concise but comprehensive textbook setting out the essentials of the science and clinical application of radiobiology for those seeking accreditation in radiation oncology, clinical radiation physics, and radiation technology. Fully revised and updated to keep abreast of current developments in radiation biology and radiation oncology, this fifth edition continues to present in an interesting way the biological basis of radiation therapy, discussing the basic principles and significant developments that underlie the latest attempts to improve the radiotherapeutic management of cancer. This new edition is highly illustrated with attractive 2-colour presentation and now includes new chapters on stem cells, tissue response and the convergence of radiotherapy, radiobiology, and physics. It will be invaluable for FRCR (clinical oncology) and equivalent candidates, SpRs (and equivalent) in radiation oncology, practicing radiation oncologists and radiotherapists, as well as radiobiologists and radiotherapy physicists.
Author: Feng Zhou
Publisher:
ISBN:
Category :
Languages : en
Pages : 148
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Book Description
Author: Committee to Assess Health Risks from Exposure to Low Levels of Ionizing Radiation
Publisher: National Academies Press
ISBN: 0309133343
Category : Science
Languages : en
Pages : 422
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Book Description
This book is the seventh in a series of titles from the National Research Council that addresses the effects of exposure to low dose LET (Linear Energy Transfer) ionizing radiation and human health. Updating information previously presented in the 1990 publication, Health Effects of Exposure to Low Levels of Ionizing Radiation: BEIR V, this book draws upon new data in both epidemiologic and experimental research. Ionizing radiation arises from both natural and man-made sources and at very high doses can produce damaging effects in human tissue that can be evident within days after exposure. However, it is the low-dose exposures that are the focus of this book. So-called “late” effects, such as cancer, are produced many years after the initial exposure. This book is among the first of its kind to include detailed risk estimates for cancer incidence in addition to cancer mortality. BEIR VII offers a full review of the available biological, biophysical, and epidemiological literature since the last BEIR report on the subject and develops the most up-to-date and comprehensive risk estimates for cancer and other health effects from exposure to low-level ionizing radiation.
