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Evaluation of the clinical results of in-vivo dosimetry in oncology in České Budějovice
ČAJANOVÁ, Nikola
Today radiotherapy or treatment using ionizing radiation effects is one of the main methods of treatment of oncological diseases. Sufficiently high doses of ionizing radiation are able to inactivate and kill cancer cells. The surrounding healthy tissue, however, these effects of radiation is harmful. The strategic aim of radiotherapy is the removal of tumor bearing the least damage to the surrounding healthy tissue. The task of the radiotherapy is to find the optimum compromise between these two conflicting requirements. Radiation treatment planning is a very lengthy and complex process. It should be precisely executed, in order to maintain the highest efficiency and safety of the treatment. The destination volume identified by the radiation oncologist must be using various imaging techniques (CT) exactly localize before start the exposure. It is also necessary to make the determination of the size of the individual and the total dose, fractionation, irradiation conditions, the size and arrangement of irradiation fields, etc. The entire planning process is the need to constantly verify. Verification is carried out during the planning of the patient, irradiation conditions (System verification), the target volume (verification) and verification of dose (measurement) to ensure the highest quality of radiotherapy. Ensuring quality in radiotherapy deals with international Quality Assurance (QA), which by law must have each of the departments of radiation oncology in the Czech Republic drawn. This program defines the procedures to be followed in order to eliminate all inaccuracies that could lead to sub-optimal treatment of radiation excessive or insufficient exposure. One of the tools for QA in radiotherapy is also the in-vivo dosimetry, which is the main subject of this Bachelor's study. Part of the verification system, and as the last fuse QA throughout the algorithm of radiation treatment is in-vivo dosimetry. Using this technique, measure input and output radiation dose in terms of in-vivo, i.e.. directly on the patient. The measurement shall be verified, that the scheduled dose agree with a dose of radiation. In-vivo dosimetry is performed on radical cancer patients during external radiation on a Linear Collider. The radiation dose is detected by using semiconductor diodes or termoluminescent materials. In-vivo measurement is not only to control the dose delivered to the target volume, but also absorbed dose in critical organs or in situations where it is difficult to predict the dose. Through the in-vivo dosimetry in time can reveal various system inaccuracies or random errors for individual patients. To detect incorrect radiation doses are used tolerance limits. When exceeding the limits it is necessary to perform a detailed inspection of all steps of the radioterapeutic process. To get acquainted with the issue of in-vivo dosimetry and its representation in the current radiotherapy was handled by the theoretical part of the Bachelor´s thesis with the use of specialized information sources...
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