Status of ion sources at National Institute of Radiological Sciences

Abstract

The National Institute of Radiological Sciences (NIRS) maintains various ion accelerators in order to study the effects of radiation of the human body and medical uses of radiation. Two electrostatic tandem accelerators and three cyclotrons delivered by commercial companies have offered various life science tools; these include proton-induced x-ray emission analysis (PIXE), micro beam irradiation, neutron exposure, and radioisotope tracers and probes. A duoplasmatron, a multicusp ion source, a penning ion source (PIG), and an electron cyclotron resonance ion source (ECRIS) are in operation for these purposes. The Heavy-Ion Medical Accelerator in Chiba (HIMAC) is an accelerator complex for heavy-ion radiotherapy, fully developed by NIRS. HIMAC is utilized not only for daily treatment with the carbon beam but also for fundamental experiments. Several ECRISs and a PIG at HIMAC satisfy various research and clinical requirements.

Amino acid transport system - A substrate predicts the therapeutic effects of particle radiotherapy

“…11 C-Met is a useful radiopharmaceutical to estimate the therapeutic efficiencies of radiotherapy such as conventional and particle radiotherapies [ 12 , 15 , 38 , 39 ]. Indeed, 11 C-Met has been used to estimate the therapeutic efficacy of carbon-ion radiotherapy at NIRS.…”

“…Under these conditions, 14 C-MeAIB uptake by tumor tissues post 6-Gy irradiation did not change up to 5 days, while the uptake and accumulation of 14 C-MeAIB by tumor tissues irradiated with 25-Gy displayed significant decrease 3 days post-irradiation ( Fig 5 ). The short half-life tracer 11 C-Met has been used to estimate the therapeutic efficiencies of particle radiotherapy in clinical practice [ 12 , 15 ] and a decrease in the uptake of 11 C-Met has been shown to represent a positive treatment effect [ 45 ]. Thus, these results suggested that early changes in the uptake of 14 C-MeAIB may also have a potential to display an early effect of the carbon-ion beam dose and tumor responses to this radiotherapy.…”

“…Since activated inflammatory immune cells are present and recruited at the irradiation sites post-irradiation and these cells also incorporated 18 F-FDG, which frequently occurs, this complicates diagnostic accuracy [ 13 , 14 ]. 11 C-Met is, therefore, frequently used to estimate the therapeutic efficacy of particle beam radiotherapy [ 7 , 12 , 15 ]. However, due to the short half-life (20 min) of the 11 C-isotope, adjacency to GMP-capable cyclotron facilities is required to produce and use 11 C-Met for clinical practice [ 16 ].…”

Evaluation of nuclear reaction cross-sections and fragment yields in carbon beams using the SHIELD-HIT Monte Carlo code. Comparison with experiments

“…About 4•10 12 methane molecules can be produced each 20 minutes. To improve the efficiency of the ion source an electron string ion source is under development phase in collaboration with the Joint Institute for Nuclear Research (JINR), Russia (Hojo et al, 2008;Noda et al, 2011;Kitagawa et al, 2012). The proton irradiation generates a sufficient number of particles, however, the number of 11 C ions which are eventually injected into the HIMAC synchrotron is limited by the rather low efficiency of the compression/ionization process (Shirai et al, 2009), 10 7 -10 8 particles per injection versus the 10 10 usually necessary for treatment (Shirai et al, 2009).…”

Advanced Treatment Planning

“…Other ion beam modalities have been investigated clinically in the past at LBL (neon, silicon and argon ions) and more have been suggested (oxygen and lithium ion beams) for future clinical practice. At the National Institute of Radiological Sciences (NIRS) in Japan, the HIMAC (Heavy Ion Medial Accelerator) can accelerate various ions (H, He, C, O, Ne, Ar, Fe, Kr, and Xe) in the therapeutic energy range. However, patients are treated only with carbon ion beams.…”