ESTRO 36 Abstract Book

S1011 ESTRO 36 _______________________________________________________________________________________________

plan was recalculated on the CBCT for the first and last fractions. Comparisons were made in terms of changes in CTV volumes over the course of treatments. Bladder, bowel and rectum dose was assessed using V30Gy and A total of 100 CBCTs from 4 patients were analysed. All CTVs were within the PTVs chosen for the PoD treatments. The median reduction of CTV volume at the end of treatments was 56%. The CTV reduced over the course of treatment in all patients, and the largest extent of volume reduction was found to be after the first 2 weeks of treatment, with a median reduction of 37%. The changes of dosimetric parameters on CTV and OARs are summarised in the table below. V40Gy. Results

hold to isocenter verification and correction was taken. In addition two MV portal images using the treatment beam to evaluate reproducibility of respiratory motion and to control heart covering in tangential fields was taken. To image analysis an Off-line Imaging Program in ARIA Oncology Information System was used. Reproducibility of movements during respiration under control of RPM system was evaluated after set-up images matching to spine and chest wall. Accuracy of patient positioning and reproducibility of respiratory motion during radiation was evaluated by analysis of tangential field imaging and effectiveness of DIBH technique by presence of heart in tangential fields. Results The average reproducibility of movements during respiratory cycle controlled by RPM system was in a row - 0,07 (±0,2); 0,003 (±0,2); -0,009 (±0,02) cm in vertical, longitudinal and lateral axis. Margin for reproducibility of respiratory cycle was calculated according to van Herk formula and equals: vertical:0,6; longitudinal:0,9 and lateral:0,1 cm. Analysis of tangential field images has shown high accuracy in patients positioning and reproducibility of respiratory motion during radiation therapy with mean systematic setup error Σ:0,037; 0,08; 0,034 cm in vertical, longitudinal and lateral axis. In spite of high reproducibility of respiratory movements and patients positioning part of the heart was included in some tangential field images. Conclusion DIBH technique is an useful irradiation method to decrease the rate of cardiac complications in left sided breast cancer patients. Developing of detailed protocol of imaging control for DIBH technique and its current analysis is essential for adequate treatment realization. In spite of good reproducibility of respiratory motion controlled by RPM and elimination of set-up error by daily imaging verification, in some cases irradiated field includes heart. It may be caused by insufficient lung expansion caused by wrong diaphragm movement, which is beyond RPM system control. Proper instructions in thoracic and abdominal breathing training are important issues in DIBH technique implementation. EP-1850 Effect on Smoking Behavior, Emotional Distress and Quality of Life in Male H/N Cancer Survivors H.Y. Kuan 1 , H.X. Zhao 2 , C.Y. Huang 2 , J.T.C. Chang 1 1 chang gung memorial hospital, Department of Radiation Oncology, Taoyuan, Taiwan 2 Chung Yuan Christian University, Department of Psychology, Chungli, Taiwan Purpose or Objective To examine the moderation of search for meaning on the relationship between presence of meaning, smoking behavior, emotional distress, and quality of life among male survivors with head and neck cancer. Material and Methods The head and neck cancer survivors completed the radical cancer treatment longer than 6 months and with smoking history were invited to the study. The participants were interviewed with Substance Use Behavior Questionnaire, Meaning in Life Questionnaire, Short Form Profile of the Mood State, and Functional Assessment of Cancer Therapy Scale-Head and Neck Version in addition to the basic personal characteristic data. Multiple Regression Analysis was used to examine the inter-action effects among different interested outcome. Electronic Poster: RTT track: Patient care, side effects and communication

Dosimetric parameters

Median % difference between the first and last fraction of treatment

D98%CTV D50%CTV

Increase by 1.15% increase by 0.77% Increase by 77.66%

V30Gy Bowel V40Gy Bowel

Increase by 129.53% V30Gy Bladder Decrease by V0.16% V40Gy Bladder Increase by 5.50% V30Gy Rectum Increase by 16.30% V40Gy Rectum Increase by 51.08%

Given that PTVs remained unchanged, it follows logically that the increased bowel dose can be directly attributed to its anatomical displacement caused by a regressing CTV. Conclusion This study has shown that consistent CTV coverage is retained through the implementation of adaptive PoD, though, the CTV volume reduces over the course of treatment. As a result, the dose to bowel increases due to the increased amount of bowel within the PTV. It is suggested that proactive replanning of these patients after the first 2 weeks of treatments might be beneficial, in order to reduce bowel dose by taking account of tumour regression. EP-1849 Implementation and verification of DIBH technique for treatment of left-sided breast cancer patients D. Dupla 1 , K. Konat 1 , M. Janiszewska 2 , A. Maciejczyk 1 , R. Matkowski 3 1 Lower Silesian Oncology Center/Wrocław Medical Uniwersity, Radiation Therapy/Oncology, Wrocław, Poland 2 Lower Silesian Oncology Center, Medical Physics, Wrocław, Poland 3 Wrocław Medical University, Oncology, Wrocław, Poland Purpose or Objective The aim of this study was to present specific way of preparation, planning and realization of deep breath-hold (DIBH) technique which is used for treatment of patients with left-sided breast cancer. Material and Methods 283 patients with left-sided breast cancer were irradiated with DIBH technique controlled by Real-time Position Management (RPM) system in Lower Silesian Oncology Center (Wroclaw, Poland) from 2013 to April 2016. Conventional fractionation of 50 Gy for breast with or without regional lymph nodes, and 56,25/60,2 Gy for simultaneous integrated boost in 25/28 fractions were prescribed. 3D, 3D/Intensity Modulated Radiation Therapy techniques were used. Correctness of realization and reproducibility of irradiation was controlled by Image Guided Radiation Therapy protocol. Before each of fractions two orthogonal paired kV images on deep breath