Visit to Taipei Veterans General Hospital
The AOCMP 2022 organizing team graciously arranged a site visit to the Taipei Veterans General Hospital Heavy Ion Therapy Center (HITC) on the evening of December 10, 2022. Delegates had a guided tour of the facility by radiation professionals of the center.
The HITC has a Carbon (C 6+) slow cycle slow extraction synchrotron accelerator. CH4 gas is the ion source. The carbon ions are accelerated to 89 energies varying from 138.3 MeV/u to 430MeV/u (70% of speed of light) with an effective range of 4g/cm2– 30g/cm2. The maximum field size at iso-center is 20 cm x 20 cm. A 3D pencil beam raster scanning system in which the beam is not switched off between 2 irradiation positions is adopted. The movement between the irradiation points is maintained fast enough for the absorbed dose delivered in between the points to be very small. The beam is temporarily turned off if the irradiation points are too far. The accelerator is coupled with a real time image gating system, an in-room CT and a 6D couch. The nozzle has main and sub parallel plate chambers for fluence measurements and multiwire proportional counter spot position monitoring for beam profile and positions near irradiation surface. Range shifters shift the irradiation volume to the desired depth and mini ridge filters expand the width of Bragg curve.
Photography was not permitted inside the accelerator vault. The faculty and staff described the parts and broadly explained the functions. It was a wonderful opportunity for the AOCMP delegates to visit the pioneers in heavy ion therapy and I would like to thank the organizers for arranging such a visit. Thank you to the members of HITC team for their explanations and warm welcome.