ESTRO 38 Abstract book

S1201 ESTRO 38

to neck and a 5-point open-face thermoplastic mask. Fiducial markers and tattoos were used for positioning reference. In addition the patient receiving TSI was also wearing a wet suit for the bolus effect. It is important that the position is reproducible and comfortable to ensure the same position during 1,5-2 hours treatment time. A small break during change of position from head first to feet first is included. Four patients received a questionnaire with 37 questions after all radiotherapy sessions was finished, which included questions enquiring their experiences during their radiotherapy sessions. Five patients were also asked to rate their pain level and level of nausea using Visual Analog Scale after every session, and if so if they vomited. Their skin and mucous membrane were observed. They all received 12 Gy/6 sessions.

(NCT03658525), to be treated on the MR-linac will receive 60Gy in 20 fractions. These patients have been advised to drink 350ml of water 30 minutes before their MR-linac appointment time, to achieve a minimum bladder volume of 250ml during treatment (O’Doherty et al, 2006). The daily volume of water drunk, and time before treatment, was recorded. A T2 weighted MR image was acquired at three time points: the start of each session, prior to treatment delivery and post treatment delivery. The bladder was retrospectively outlined for all three images. The volume of the bladder and time of MRI acquisition documented. The average rate of intrafraction filling was determined. The dose delivered to the re-outlined bladder at each timepoint was re-calculated and documented to assess if mandatory dose constraints were met with the initial bladder size and increased bladder size pre and post treatment. The effect on dose constraints will be investigated. Results The bladder filing guidelines were altered 11 times during the course of treatment. The patient drank 1 to 2 cups of water 25 to 35 minutes before treatment and had to partially empty his bladder 12 times prior to treatment. We will continue to assess the revised guidelines on future patients. The median (range) percentage increase in bladder volume across 25 minutes from initial planning MRI to pre- treatment MRI was 62% (34% to 126%) and across 36 minutes from initial planning MRI to post treatment MRI was 89% (46% to 174%). The mean (SD) rate of bladder filling was 4.3cc per minute (1.5cc per minute) from initial planning MRI to post treatment MRI. For the first fraction the mandatory bladder dose constraints were met for all three time points. Further fractions will be investigated. Conclusion Although the bladder filling guidelines were altered regularly, our initial analysis has indicated that the mandatory bladder dose constraints were achieved. The rate of bladder filling during treatment delivery indicated the bladder volume was at recommended minimum for departmental guidance. The advantage of bladder filling displacing small bowel superiorly was noted across the course of treatment and will be investigated further. EP-2174 Patients’ experiences with whole body irradiation using Tomotherapy P. Schon 1 , P. Lannerheim-Saure 1 , C. Hagstrom 1 , A. Löfgren 1 1 Skåne University Hospital, Department of Radiation Therapy, Lund, Sweden Purpose or Objective At our clinic, the traditional Total Body Irradiation treatment (TBI) using a linear accelerator has been replaced with Total Marrow Irradiation (TMI) with Tomotherapy, treating patients with leukaemia prior to stem cell transplantation. The reason to use TMI instead of TBI is to minimize dosage to healthy tissue. Total Skin Irradiation (TSI) is a similar treatment used for treating patients with severe mycosis fungoides. To be able to complete the treatment, the patient´s well-being is crucial during the treatment. Therefore quality control that focus on the patient´s experience is imperative. The purpose was to explore the patient's experience of full body irradiation, when treated with Tomotherapy. Material and Methods The oncology nurse perform the preparations, which includes giving information and support based on the patient´s need prior to the start of the treatment. TMI- and TSI-treatments were similar to each other concerning immobilization and position of the patient. The patient was immobilized using a large vacuum cushion, from feet

Results All patients felt some level of pain and chafing during treatment (Fig 1). The TBI-patients felt more pain and nausea. The TSI-patient´s skin improved during all sessions, but there were some bleeding. All patients felt safe, but the TBI-patients found the environment more frightening. The TSI-patient lacked information about side-effects and self-care, but found the overall information sufficient. None of the patients felt completely relaxed, but they all felt that the treatment sessions were manageable, though the treatment time was The quality control revealed that the patient were lacking some information and support. The oncology nurses should focus on information and prevention to increase the patient´s well-being. To minimize treatment time the nurse ought to develop skills handling the technology and treatment procedure. Based on the results, the patients´ positioning was improved owing to some modifications, minimizing pressure and enhancing mobility of vulnerable parts of the body. EP-2175 No more Lines – Omitting skin marks, safe to align with tattoo only for lung cancer patients? L. Wiersema 1 , J. Stam 1 , T. Wiersma 1 , J. Belderbos 1 , A. Licup 1 , F. Koetsveld 1 , P. Remeijer 1 1 Netherlands Cancer Institute, radiotherapy, Amsterdam, The Netherlands Purpose or Objective In our department besides ink tattoos, skin marks are used for patient positioning treated within the thoracic area. The tattoos and skin marks are placed by RTT’s during the Computed Tomography (CT) simulation. The added value of the skin marks is being questioned by physicians and RTT’s. Patients are instructed to retrace the skin marks until the first day of treatment in case of fading, this introduces a risk of shifting the skin marks. Besides, there is also a degree of discomfort for the patients, because the skin marks might show from underneath their clothes, whereas some patients may also present with an allergic reactions to the ink. The purpose of this study was to see challenging. Conclusion