TURKISH JOURNAL OF ONCOLOGY 2023 , Vol 38 , Num 3
To study the Multimodality End-to-end Testing for Bilateral Metallic Implant in Pelvis
Pawan Kumar SINGH1,Deepak TRIPATHI1,Rohit VERMA1,Sukhvir SINGH3,Manindra BHUSHAN4,Kothanda RAMAN4,Soumitra BARIK4,Gourav KUMAR4,Munish GAIROLA4
1Department of Physics, Amity Institute of Applied Sciences, Amity University, Noida (U.P.)-India
2Department of Physics, USAR, Guru Govind Singh University, Surajmal Vihar, New Delhi-India
3Radiological Physics & Internal Dosimetry Group, Institute of Nuclear Medicine & Allied Sciences, Defence Research & Development Organisation, New Delhi-India
4Division of Medical Physics, Department of Radiation Oncology, Rajiv Gandhi Cancer Institute and Research Centre, New Delhi-India DOI : 10.5505/tjo.2023.3892 OBJECTIVE
The end-to-end (E2E) testing method enables understanding the difficulties and uncertainties in treating any specific case type. This study was focused on bilateral metallic implant cases.

METHODS
The study was performed on a cylindrical phantom of Perspex with holes for implant inserts. Two stainless steel metal rods of 7.5-8.0 g/cc mass density were inserted in the phantom. The ionization chamber CC13 was kept at a 5 cm depth in the phantom. The phantom was scanned on a computed tomography simulator in pelvis protocol with a 1mm slice thickness. The scans were imported to the contouring station without applying artifacts correction. Chamber volume was contoured as gross tumor volume (GTV); margin to GTV, clinical target volume, and planning target volume were created. Four isocentric plans (Conventional, three-dimensional conformal radiotherapy[3D-CRT], intensity-modulated radiotherapy [IMRT], and volumetric-modulated radiotherapy [VMAT]) were generated for two LinacsTruebeam (TB)-sTx and 2300-CD. The conventional plan was a single anterior field, 3D-CRT was four field box techniques, IMRT was seven field plan, and VMAT was with two complete arc. Pre-treatment verification was done using CBCT. Four plans were created on helical tomotherapy with different prescriptions and delivered using MVCT guidance.

RESULTS
In conventional plans, variations were -1.40%, -1.57%, and for 3DCRT, variations were -5.08% and -4.93%, for IMRT, the differences between measured and TPS doses were 1.84 % and -1.55% for VMAT plans, and the variations were 0.68% and -0.88% for TB and 2300-CD, respectively. The tomotherapy plans with gradient showed deviations more significant than 3%. Similarly, the variations for single prescription plans were within 3%.

CONCLUSION
The phantom design used in the test provided a comprehensive understanding of simulation and delivery problems. Keywords : End-to-end; metallic implant; MVCT; phantom study