patient-specific dosimetric validation of pelvic imrt and vmat plans using a custom-designed female pelvic phantom and arc-check qa system

Introduction: to ensure the accuracy of advanced radiotherapy techniques in the therapy of female pelvic malignancies using radiotherapy, comprehensive quality assurance protocols and patient-specific dosimetry was performed using a custom-designed female pelvic (cdfp) phantom and arc-check.material and methods: volumetric modulated arc therapy (vmat) and intensity modulated radiation therapy (imrt) plans originally developed for patients with cervical cancer were transferred to the cdfp phantom and arc-check. the doses for patient-specific quality assurance (psqa) of advanced techniques were calculated using different algorithms in treatment planning system (tps). to acquire dose measurements, a 0.600 cc ion chamber, sun nuclear 125c (snc125c) and a pinpoint 0.015 cc chamber were employed. the percentage deviation between the computed and administered dose was calculated. results: percentage discrepancies between planned and administered doses were analyzed. the maximum percentage deviation, mean ± standard deviation(sd) differences for 0.6 cc ion chamber and a pin-point 0.015 cc chamber were found to be -3.6%, -0.89% ± 1.59  and 3.51%, 1.10% ± 1.31  for the imrt treatment technique and -3.32%, -0.84% ± 1.53 and 3.6%, 1.25% ± 1.34 for the vmat treatment technique using aaa algorithms using 6mv beam for cdfp phantom respectively. the maximum of percentage deviation, mean ± sd differences for 0.6 cc ion chamber and a snc125c chamber were found to be -3.40%, -0.273% ± 2.161 and 3.107%, -0.028% ± 2.046  for cdfp phantom and -2.72%, -0.35% ± 1.41 and 2.74%, 0.197% ± 1.50 for arc-check using vmat treatment technique using 6mv beam and monte carlo algorithm respectively.conclusion: the inherent properties of anthropomorphic phantoms like the cdfp, such an anatomical fidelity and tissue equivalence, make them extremely useful in the quality assurance radiotherapy-programs. their application increases the accuracy of dosimetric validation and therefore, these phantoms are applicable in the use of high-accuracy treatment modalities such as imrt and vmat