Evaluatıon of the treatment fıeld devıatıons ın dıfferent set-up posıtıons durıng thoracıc radıotherapy ın lung cancer patıents

Purpose: To evaluate the treatmant field deviations in lung cancer patients treated with thoracic radiotherapy in three different set-up position and the influencing factors.Patients and Methods: 30 lung cancer patients having the indication for palliative thoracic radiotherapy, were randomised into three different set-up positions (arm along the body, lung board, armrest lung board) between April ? July 2011 in Dokuz Eylül University Oncology Department. The treatment field deviation were measured 2, 3, 4 times depending on total treatment time, on sternal and axiller cross. All the deviations were recorded on (x), (y), right and left (z) and (?) axis, Corrected Bonferonni Kruskal-Wallis used to compared the deviation in every axis, Non-parametric Friedman to compare the interfractional deviations. Correlation test is used to evaluate influencing parameters to the field deviations.Result: Mean significant differences of 5,66±4,15 mm p:0,49 deviations are observed in the right (z) axis and 5,53 ±4,81mm in the left (z) axis. No statistically significant deviations were found in interfractional deviation in every axis. There is no relation between the pain scor and field deviation. There is a statistically but not clinicall corelation between age, PTF, educational statu, heat differences and total fraction treatment.Conclusion: Both set-up position with lung board with armrest and arm along the body, gave better results than the lung board. According to our results, ıf lung board wıll be used adding the armrest will be mandatory. If arms along the body position is used, putting the field axis on half body layer of the patient is necessery in order to draw the cross on the body. Eventual errors can be minimised and theset-up quality improved by minimizing the total treatment time in every fraction and with can be air conditionig system, balancing the in and out door tempereture.Key Words: Set-up error, treatment field deviation, lung cancer, palliative radiotherapy, immobilization.