Experimental validation of Monte Carlo dosimetry for therapeutic beta emitters with radiochromic film in a 3D‐printed phantom

• DOI: 10.1002/mp.15926
• Publication Date: 2022-08-19T10:10:04Z
• Authors: Benjamin Van; Yuni K. Dewaraja; Jeremy T. Niedbala; Gerrid Rosebush; Matthew Kazmierski; David Hubers; Justin K. Mikell; Scott J. Wilderman
• Keywords: Dose profile

Validation of dosimetry software, such as Monte Carlo (MC) radiation transport codes used for patient-specific absorbed dose estimation, is critical prior to their use in clinical decision making. However, direct experimental validation the clinic generally not performed low/medium-energy beta emitters radiopharmaceutical therapy (RPT) due challenges measuring energy deposited by short-range particles. Our objective was design a practical phantom geometry radiochromic film (RF)-based measurements beta-emitting radionuclides and perform experiments directly validate our in-house developed Dose Planning Method (DPM) MC code dedicated internal dosimetry.The setup designed from that have range sufficiently penetrating ∼200 μm water well capture any photon contributions dose. Assayed 177 Lu 90 Y liquid sources, 13-450 MBq estimated deliver 0.5-10 Gy sensitive layer RF, were injected into cavity two 3D-printed half-cylinders had been sealed with 12.7 or 25.4 thick Kapton Tape. A 3.8 × 6 cm strip GafChromic EBT3 RF sandwiched between taped half-cylinders. After 2-48 h exposures, films retrieved wipe tested contamination. Absorbed measured using commercial triple-channel optimization method calibration generated via MV beam. Profiles analyzed across central 1 cm2 area validation. Eleven completed nine both saline bone equivalent solution. Depth curves stacking multiple strips single filled half-cylinder an acrylic backing. All modeled DPM generate voxelized estimates. We extended study benchmark general purpose MCNP6 EGSnrc against results well.A total 20 showed phantoms final values reproducible. The agreement estimates on average -4.0% (range -10.9% 3.2%) all -1.0% -2.7% 0.7%) experiments. depth agreed 1.2% -8.0% 15.2%) depths 4.0% -5.0% 9.3%) Y. MCNP board, within 4.7% 3.4% respectively, geometries depths. betas greater than 92% (betas + other radiations) Lu, indicating measurement dominant contribution design.The reproducible insert simple sources demonstrate this reliable experimentally validating algorithms therapies unsealed sources. doses close codes, thereby RPT dosimetry.