ESTRO 2023 - Abstract Book

S2044

Digital Posters

ESTRO 2023

As of 19th October 2022, 1080 patients were invited to use the system 753 patients have actively used the system. The mean age of patients is 62.9 years old. Of note there are 161 patients between 70 and 79 years and 56 patients over the age of 80. The majority of patients using the system have a diagnosis of breast cancer (37.4%) followed by prostate (15.9%). When care teams have responded to patient’s questionnaire entries or symptom entry patients have rated the response as 4.56 out of 5.0. There have been 796 questions about a symptom entered by patients and 603 responses back to patients. We have sent 8210 automated messages to patients. 890 patient information articles (leaflets or URLs) have been sent to 415 patients. Conclusion We have seen a good initial uptake to the system. Patients from an older age group were still active in use of the system in spite of fears they would be put off by a digital platform. The cancer diagnosis reflects the distribution of work in our department. Satisfaction scores were high. Early positive experience means we will now further integrate Noona into more clinics/clinical scenarios. Purpose or Objective Head and neck cancer (HNC) requires robust immobilisation, with thermoplastic masks, to ensure safe delivery of radiotherapy (RT) dose to planning target volumes. RT technique precision has evolved over the past decade optimising dose delivery, however, neck flexion and shoulder position may vary daily requiring repeat imaging on set-up. These variations can change the treatment plan dosimetry due to the steep dose gradients. This evaluation aimed to compare immobilisation systems, report the set-up errors for each and determine which reduced imaging frequency during treatment. Materials and Methods This prospective comparison was undertaken between September 2021 and March 2022. All HNC patients and subsites were included. Patients were selected consecutively from the RT patient management system. All patients were positioned with the pro-step knee rest and one of the below systems (a,b,c). b) Klarity 2.4mm thick (15% perforation) 5-point head and shoulder mask, foam HR plus an additional individualised accu-cushion placed on the HR and moulded to the patients neck. c) Portrait 3.2mm thick S-Frame mask with reinforced strips at the forehead, chin and shoulders, a plastic silverman HR and accu-cushion under the neck. The Klarity masks were connected to the IMRT board attached at the end of the treatment bed. The Portrait masks connected to an overlay board placed on top of the treatment bed, secured by a locking bar. IGRT involved acquisition of daily online 2D-KV orthogonal images, with shifts applied pre-treatment delivery. Patient’s were reset-up and reimaged where gross error was obvious on acquired images to improve neck flexion, rotation and lateral movement. Data collected included the number of reset-ups, the total 2D-KV images acquired and the mean 2D-KV images over a treatment course. Systematic and random errors were calculated. The Anova one-way and Tukey tests were used to compare mean shifts between the groups using the SSPS system, p ≤ 0.05. Results 51 patients were included. All received radical RT over 30 fractions, except 1 patient in group (c) who had 20#s. For groups a) and b) 1200 images were expected over a treatment course in each group, however 199 (16.6%) additional images were acquired in group a) and 161 (13.4%) in group b). For group c) there was 76 additional (11.9%) images of an expected 640. Table 1 displays a breakdown for each cohort. Immobilisation systems; a) Klarity 2.4mm thick (15% perforation) 5-point head and shoulder mask, foam headrest (HR). PO-2273 Comparison of immobilisation, imaging and set-up errors during head and neck radiotherapy L. Hay 1 , L. Devlin 1 , A. Duffton 1 1 The Beatson West of Scotland Cancer Centre, Radiotherapy, Glasgow, United Kingdom

Population mean imaging shifts, SD, range, systematic and random set-up errors are shown in table 2.

The mean shifts between the groups do not differ significantly in any direction, vert F(2, 48)=1.65, p ≤ 0.20, long F(2, 48)=0.19, p ≤ 0.83 and lat F(2, 48)=0.71, p ≤ 0.50.