ESTRO meets Asia 2024 - Abstract Book

S344

Physics – Quality assurance and auditing

ESTRO meets Asia 2024

acceptance tests as per manufacturer’s CAT procedure followed by commissioning tests and guidelines laid down by IEC protocols (IEC 60601 & IEC 60976) and local competent authority (AERB,India) . In this study, the results of safety checks, mechanical tests & dosimetric measurements are presented.

Material/Methods:

The Shinva XHA600E equipped with digital platform and MV portal imaging resolution of 2048 x 2048 pixels capable to deliver 3D conformal, Dynamic-IMRT and VMAT technique with dose rate ranging from 0 to 600 MU/min and asymmetric jaws of maximum field size of 40x40 cm 2 followed by 40 pairs of tertiary MLC made of tungsten material & leaf speed of 3cm/sec. The accuracy of MLC leaf position is ensured with encoder method. Dosimetric measurements were performed using 0.6cc Ionization Chamber for larger field sizes and semiflex chamber for small field sizes. The PDD & Profile measurements were performed with PTW MP3 –M RFA water phantom with scanning capacity of 50x50x50 cm 3 . Radiochromic films were used for VMAT performance tests, field congruence tests & spoke tests of gantry, collimator and couch.

Results:

Acceptance test begins with safety checks to ensure safe environment for staff and public. The electrical tests and radiation safety tests satisfied all safety interlocks as per IEC 60601 and AERB recommendations with LASER based anti-collision interlock. The observed average radiation leakage through X&Y collimator jaws at NTD was 0.71% & 0.52% respectively. The transmission leakage through tertiary MLC was 2.33%. The iso-centre spoke tests of Gantry, collimator & couch were found ≤1mm. The field congruence for 5x5-30x30cm 2 showed deviation of 1 mm. All the mechanical test results are well within tolerance limits including VMAT technique. The beam quality index was 0.671(0.667±3%). The PDD was 67.09% (67.5±2%) and Dmax was 1.5 cm (1.5±0.2cm) for 10x10cm 2 . The beam penumbra for 10x10 cm 2 at Dmax is ≤ 6.00 mm for XY profiles. The photon beam reproducibility and MU linearity were 0.072 % and 0.45% respectively. The maximum deviation of Monitor response at different gantry angles was 0.343% and beam stability throughout the day was 0.256%. The flatness and symmetry for various static gantry and ARC mode field sizes at 10.0 cm depth in isocentric setup was well within the tolerance limits. For VMAT performance tests, the monitor chamber constancy during ARC mode was 0.120% and accuracy of dose with variation of dose rate and gantry speed was 1.067%.

Conclusion:

Acceptance and Commissioning tests of Shinva Linac XHA600E with digital platform and VMAT technique were analyzed and were found satisfactory as per the IEC standards & local competent authority (AERB) recommendations.

Keywords: LINAC COMMISSIONING, SHINVA LINAC ,ACCEPTANCE TEST

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