ESTRO 2024 - Abstract Book

S3410

Physics - Detectors, dose measurement and phantoms

ESTRO 2024

Carbon ions (320 MeV/u), position 2

0.00087 (10)

Conclusion:

The results suggest that the sensitivity of the FRICKE solution decreases with increasing LET, a clear LET-dependence is seen in both, the simulations and experiments. However, both approaches still need to be optimized. The signal to-noise ratio when measuring the absorption is very low due to the small signal and a reason for the high uncertainties. To further investigate dependencies affecting experimental G-values, a flurescence marker will be used next. The FRICKE solution showed a number of dependencies (for example oxygen concentration) in the experiments, which could have a significant influence on the measurements, that will be investigated in further studies.

Keywords: Fricke solution, dosimetry, particle therapy

3252

Digital Poster

Control limits for single isocenter multiple brain targets SRS PSQA with a high resolution detector

Serenella Russo 1 , Andrea Bruschi 1 , Alessandro Ghirelli 1 , Silvia Pini 1 , Paolo Alpi 2 , Raffaella Barca 2 , Simona Fondelli 2 , Barbara Grilli Leonulli 2 , Camilla Delli Paoli 2 , Fiammetta Meacci 2 , Lisa Paoletti 2 , Silvia Scoccianti 2

1 AUSL Toscana Centro, Medical Physics, Florence, Italy. 2 AUSL Toscana Centro, Radiotherapy, Florence, Italy

Purpose/Objective:

Single ‐ isocenter multiple brain metastasis stereotactic radiosurgery (SRS) is an advanced treatment modality largely increasing in clinical practice due to the efficiency benefits. The increased confidence in the accuracy of the planning and delivery technology has fostered the clinical use of this tecnique. Thus, Patient Specific Quality Assurance (PSQA) procedures play a crucial role in ensuring the safety and effectiveness of SRS treatments. The spatial resolution of the measurement system for PSQA has the utmost importance and should be adequate to sample the SRS volume. New generation device (myQA SRS, IBA Dosimetry) suitable for online verification and with a “film like” resolution has recently become available. The aim of this work is to evaluate tolerance limits according to TG-218 recommendations for PSQA performed by this new device in single ‐ isocenter multiple brain metastasis SRS.

Material/Methods:

PSQA measurements were performed by the complementary metal oxide semiconductor detectors of the myQA SRS matrix, which has a sensor grid of 300 × 350 pixels with a spacing of 400 µm in an active area of 120 mm x 140 mm. The myQA SRS is located inside the myQA SRS phantom specially designed to house the detector for end to-end dosimetry testing, even for verification of non-coplanar beams, thus ensuring to measure using a true