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Evolution of radiotherapeutic methods from 2D to 3D techniques in radiotherapy of the head and neck area
URBANOVÁ, Petra
Malign tumours of the ENT area rank fifth to sixth in the global occurrence of malignities. Two thirds of patients with head and neck tumours start their treatment with locally developed condition. In the Czech Republic, head and neck tumours represent 2 {--} 3 % of all malignant tumours. The most common head and neck tumours occur in the areas of larynx, hypopharynx, and oropharynx. In the everyday life, the face, head, and neck represent areas most exposed in external contact, perception, and control of oneself. The centres of mimics, communication, and speech are located there. Head, neck, and especially the face are the most visible parts of the human body. This also makes for the specific nature of oncological conditions of the head and neck. Currently, thanks to modern technologies, powerful computer systems, and a range of modern appliances, radiotherapy takes up prominent position in the treatment of head and neck carcinomas. Thanks to advanced imaging technologies, new techniques can be performed with linear accelerators, especially the IMRT and IGRT methods. These techniques allow for substantially lower radiation load on the surrounding healthy organs, which was not possible previously. Results of comparative studies based on average values speak clearly for the latest technologies and modern IMRT techniques. The resulting dosage load on the critical organs (the spinal cord) is much higher in patients planned with the older techniques than in the case of the IMRT. When using IMRT techniques, dose gradient is steeper, and so are the mean dose values (Dmean), than in the case of 3D techniques planning, which allows for the escalation of the dose in the target volume in the next phases of radiotherapy. The other studied parameter is also lower {--} the maximum dose in the PTV target volume, which is usually easy to keep below 107 % of the total prescribed dose (in accordance with international recommendations the dose in target volume should range between 95 % and 107 % of the total dose). The aim of the bachelor{\crq}s thesis was to compare the new and older radiotherapeutic methods applied to the head and neck area. Comparing these methods is very complicated as the planning itself is a sophisticated issue. The evaluation was carried out through statistic processing of 25 patients treated with the IMRT technique. In order to make the comparison as exact as possible the 3D plan was performed also on identically designed target volume.
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