(Sunday, 7/14/2019) 3:30 PM - 4:00 PM
Room: Exhibit Hall | Forum 6
Purpose: With technical advances in radioactive isotope generation, isotopes with positron decay (PDI) become a viable alternative to their stable counterparts for hadrontherapy. With substantial signal boosting for positron emission tomography (PET), PDI is promising for accurate and precise online beam range (RB) verification. However, the quantification is still lacking to date. In this study, we quantitatively investigated the performance of prompt gamma imaging (PGI) and PET for the radioactive C-11 ion beam.
Methods: Geant4 10.3.p02 was employed to simulate dose, prompt gamma (PG) and annihilation gamma (AG) distributions generated from C-11 and C-12 ion beams impinging water and PMMA phantoms. QGSP_BIC_HP physics-list was used to govern the relevant physics processes for four therapeutic energies (ET) (to reach the same penetration depth at each energy level for two species). Post processing to obtain PGI and PET was performed with in-house-developed software and GATE, respectively. PG yield distributions with time-of-flight (TOF) and energy selection and AG yields with different acquisition times were compared between C-11 and C-12.
Results: For water phantom at the lowest ET, the measured PG counts from C-11 were 25% lower with TOF window of [0.1, 0.4] ns and energy window of [2, 7] MeV, while AG was 8 folds higher for an acquisition time of 5 min, respectively, than that from C-12. For the highest ET, PG and AG for C-11 are 9% lower and 1.09 folds higher, correspondingly. In general, with the increasing ET, PG yield rates decreased, while AG yield rates increased for both species. With a 5-min acquisition, FWHM were 0.61 mm for C-11 and 6.01 mm for C-12 at the lowest ET. Results in PMMA were similar to those in water.
Conclusion: C-11 ion beam can be an excellent option for accurate and precise online RB verification using combined PGI and PET.
Funding Support, Disclosures, and Conflict of Interest: This work was supported in part by the UT Southwestern Medical Center under Particle Therapy Seed Grant. All the simulations were performed at Texas Advanced Computing Center.
Keywords
Not Applicable / None Entered.
Taxonomy
Not Applicable / None Entered.
Contact Email
