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Radiotherapy of breast cancer
TRAKALOVÁ, Barbora
Diagnosis code C50 represents malignant neoplasm of breast. It is the most frequent tumour disease in women. In 2009, 5975 cases were newly diagnosed in women in the Czech Republic and 1607 women died of this disease. There exist many risk factors which can cause tumour such as hereditary disposition, age, menses, menopause and other factors. At the same time, we can influence many factors and so prevent the disease. Prevention is also important, whether in the form of self - investigation of breast or mammography screening, which is recoverable by insurance from the age of 45. Treatment of breast carcinoma includes a lot of medical modalities such as surgical, hormonal and biological treatment, chemotherapy and radiotherapy. This thesis deals in more details with radiotherapy which is irreplaceable in treatment of this disease. Radiotherapy is a treatment of malignant and benign tumours by means of ionising radiation. In order to treat patients with radiotherapy, a team of doctors and radiologists shall create an individual radiation plan for them including the exact target volume, critical organs, radiation technology, fractionation and particular radiation exposure, radiation position and many other data necessary to accurate irradiation. A technology of two tangential fields is the most applied technology at breast cancer treatment. This technology is also applied in Nemocnice České Budějovice a.s. where I have created a file of 60 patients with breast carcinoma treated on oncology department in the year 2011. There have been used 536 verification images on the whole, it means 1608 evaluation. In course of treatment a patient should have an identical radiation position, which is reached with irradiation and fixation aids. However, from various reasons small or bigger deviations from the optimal position happen and therefore a possibility of irradiation of another volume than the required target one can occur. It is necessary to be aware of the fact that during a treatment of oncology patients there can often appear change of weight, change of body shape of a patient and at advanced stages even also change of physical state and movability of a patient. Therefore large deviations can happen in patients with breast carcinoma namely for example in case of breast deformation or abnormal loss of weight due to the treatment. In Nemocnice České Budějovice a.s., the maximum allowed deviation for vertical, lateral and longitudinal axis is stated 0,7 cm and for rotation 3°. I have noticed the acquired deviation values from verification images into a chart and consequently into a figure where are shown the average deviations and frequencies of these deviation in particular axes for each radiation field. The biggest deviation has happened in vertical axis and the average deviation in that axis was 0,29 cm. The maximum allowed deviation was exceeded only at 3 %, so at 45 deviation from the total evaluation. This thesis should prove the fact that verification images enable to prevent possible errors during radiotherapy. This hypothesis has been confirmed because only 3 % evaluation exceeded the maximum allowed deviations. Verification images enable us to disclose wrong irradiation position, therefore only the target volume is irradiated and follows no irradiation of the surrounding healthy tissue and critical organs.
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Importace of verification treatment irradiaton position of IMRT prostate
KŘÍŽOVÁ, Marcela
Prostate cancer is the most frequent oncological disease in men. Based on the disease phase and extent, patiens with prostate carcinoma diagnosis are treated with number of different therapies including radical prostatectomy, hormone therapy, chemotherapy, brachytherapy, conventional radiotherapy, conformal radiotherapy and combination of these. This Bachelor Thesis deals with prostate carcinoma treatment using a special conformal radiotherapy method - IMRT (Intensity Modulated Radiotherapy). The first section describes the disease charakter from the clinical point of view and the disease diagnosis, followed by treatment modalities. The main part examines and describes IMRT, treatment planning and resultes from statistic evaluation of irradiation position deviations. IMRT technique allows escalation of the irradiation dose while protecting critical structures. In this way the patient can be irradiated with a total dose of 80 grays (Gy). Patients are irradiated in a linear accelerator. Modulation of the radiation beam using multileaf collimator allows irradiation of different segments of target volume with different doses, so that overal homogenity of the irradiation treatment is achieved through nonhomogenous distribution of the dose. Escalation of the irradiation dose is in a close relationship with the irradiaion position and isocentre position kontrol, so that the treatment quality is guaranteed preventing damane to surrounding healthy tissue. Fixing the patient in irradiation position as well as reproductibility of the position is of essentials importance. The isocentre in irradiation position is verified efore every fraction. Verification portal images are acquired using EPID (Electonic Portal Image Device) Portal Vision LC 250 and then compared with reference verification images acquired by CT when planning the treatment. Portal images are made up of two fields of 12x12 cm size under 0 and 90 or 270 degrees. Deviations are recorded in craniocaudal, mediolateral and anterior-posterior axes, and if they exceed 3mm, the irradiation position is corrected on the irradiation table. In this Thesis, deviations in a group of 30 patients were evaluated using the Aria-Offline Review programme which is an accesory to the treatment planning system. In one third of the statistical group of patient, deviations identified using on offline review were compared with deviations identified by start efore each fraction. Dutiny statistical processing, deviations were recorded within ranges 0-3 mm, 3,1-5 mm and over 5mm. 69% of acceptable deviations were recorded within the 0-3 mm range in the craniocaudal axis, 71% in the mediolateral axis and 67% in the anterior-posterior axis. Based on a complete analysis and evaluation of the deviations we can conclude that verification of the irradiation position in treatment of prostate carcinoma using IMRT is essentials to guarantee the irradiation treatment quality. We have also verified that deviations between 0 and 3 mm are acceptable and in no way impair the treatment quality.
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