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Analysis of deviations in the localization of radiation fields in the course of radiation by means of EPID in patients with tumours in head and neck
GRABMÜLLEROVÁ, Hana
Oncology diseases are serious and alarming problems in the world and our country, too. The most common ENT tumours affect larynx, oropharynx and hypopharynx. The factor which causes the occurrence of tumours is smoking. Chronic thermal excitation, pH changes of mucous membrane and vasoconstriction caused by nicotine can also participate in the occurrence of malign changes. Among other etiological factors belong: alcohol, U radiation, ionizing radiation, transport and industry exhalations, nutritional exhaustion, and immunodeficiency. Current treatment includes surgery, radiotherapy, cytostatic chemotherapy, hormone therapy, bio therapy and their combinations. The prosperity of oncology patients is 22% by surgery, 18 % by radiotherapy and 5% by chemotherapy. Radio therapy remains the basic treatment of oncology diseases. According to the newest knowledge and requests its quality is ensured. The accuracy of radiation treatment and the increases in therapeutic results are developed. The risk of over dosing, which leads to the occurrence of many complications, and also the risk of under dosing, which decreases the chance of the complete cure, decline. Quality assurance is currently carried out on electronic portal image device EPID (Electronic Portal Imaging). The reason of permitted small deviation (0,3cm) in tumours of head and neck is the proximity of critical organs to the target volume and often small radiated volumes. The aim of the thesis was the analysis of the group of patients with the tumours of head and neck treated at oncology department in Nemocnice České Budějovice, a.s. (Hospital in České Budějovice Inc.) by the form of portal evaluation. The hypothesis was average deviation 0,3cm in localization of radiated fields in the evaluated group. The analysis of deviations in localization of radiation fields in the course of radiation of evaluated group was carried out. The gained deviations were compared with the data in professional literature. The methodology included the characteristics of evaluated group of patients according to radiation posture, fixation of a patient, radiation technique, localization of tumour, the extent of disease TNM, patient´s age and sex-a man, a woman. The evaluation was carried out by means of EPID for particular radiation fields. Statistically, maximum, minimum and average deviation in localization of radiation fields was evaluated and the results were compared with the hypothesis by means of the test {$\psi$}2. The presupposed hypothesis was not proved. From the measured data it was found out that in practice acquired deviations are smaller than deviations presupposed by the hypothesis. The important part of radio therapeutic practice is the programme of Quality Assurance (QA). The results will serve the workers of radiation oncology in Nemocnice České Budějovice, a.s. (Hospital in České Budějovice Inc.) for evaluation of radiotherapy quality in the tumours of head and neck.
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