ESTRO 2022 - Abstract Book

S267

Abstract book

ESTRO 2022

Results The investigation showed the efficacy of various hearing protection tested. Table 1 shows the SPL measured along with the calculated SNR and manufacturer-quoted SNR. SFEP showed the most attenuation. SEP and OP had a similar performance The recorded levels of the scanner exceed 80dB, therefore hearing protection must be worn to reduce the SPL at the ear drum to 85dB(A). SEP is preferred over OP, although the acoustic noise results is 2dB above the recommended level, 87dB, it does not require specialist training to fit unlike the putty. The risk of damaging the hearing of patients fitted with SEP is minimal given short scan times.

Conclusion In RT there has been little research into appropriate hearing protection for paediatrics. SEP, are recommended for use. These measured a minimally greater noise level than OP. However, OP requires specialist training to fit, which is inappropriate for RT workflow. This work is not only very important in the context of having of having a dedicated MRI in RT but also future proofing patient welfare as we move towards MR only planning. Future work to be undertaken to ensure exam times do not exceed 45mins and that staff are trained appropriately to fit the recommended earplugs.

MO-0306 Comparison between 2 surface guidance systems for lung treatments

W. Vingerhoed 1 , P. Brokken 1 , D.N.H. Flavia 1 , G. De Kerf 1 , K. Schaerlaeken 1 , A. Sprangers 1 , D. Verellen 1

1 GZA, Radiotherapy, Antwerp, Belgium

Purpose or Objective With the introduction of a second system for SGRT(3) on 9 linacs (next to the previous SGRT(1) system for SBRT applications on a Varian TrueBeam STX platform), we investigated the positioning residual error obtained by Cone Beam CT matching after surface guided positioning for lung patients. Further, we compared 2 different surface scanning systems and 2 different immobilization devices for the thorax. In addition, a comparison with conventional lung treatments with external markings was performed. Materials and Methods A search on our ARIA database yielded the online matched parameters of all the lung patients who were irradiated in the first 10 months of 2022. Further a historical dataset was retrieved one year earlier for patients positioned on device A[2] 1 with SGRT[1] 2 to compare both SGRT systems. Patients with arms positioned next to the thorax were excluded. Further, the data were sorted according to the positioning technique. This resulted in 4 groups:

1) 123 patients positioned (2420 fractions) on device A[2] without surface guidance 2) 55 patients positioned (1053 fractions) on device A[2] with SGRT[3] 3