System evaluation of automated production and inhalation of O-15-labeled gaseous radiopharmaceuticals for the rapid O-15-oxygen PET examinations

Background(15)O-oxygen inhalation PET is unique in its ability to provide fundamental information regarding cerebral hemodynamics and energy metabolism in man. However, the use of O-15-oxygen has been limited in a clinical environment largely attributed to logistical complexity, in relation to a long study period, and the need to produce and inhale three sets of radiopharmaceuticals. Despite the recent works that enabled shortening of the PET examination period, radiopharmaceutical production has still been a limiting factor. This study was aimed to evaluate a recently developed radiosynthesis/inhalation system that automatically supplies a series of O-15-labeled gaseous radiopharmaceuticals of (CO)-O-15, O-15(2), and (CO2)-O-15 at short intervals.MethodsThe system consists of a radiosynthesizer which produces (CO)-O-15, O-15(2), and (CO2)-O-15; an inhalation controller; and an inhalation/scavenging unit. All three parts are controlled by a common sequencer, enabling automated production and inhalation at intervals less than 4.5min. The gas inhalation/scavenging unit controls to sequentially supply of qualified radiopharmaceuticals at given radioactivity for given periods at given intervals. The unit also scavenges effectively the non-inhaled radioactive gases. Performance and reproducibility are evaluated.ResultsUsing an O-15-dedicated cyclotron with deuteron of 3.5MeV at 40A, (CO)-O-15, O-15(2), and (CO2)-O-15 were sequentially produced at a constant rate of 1400, 2400, and 2000MBq/min, respectively. Each of radiopharmaceuticals were stably inhaled at </p

Identification of 45 New Neutron-Rich Isotopes Produced by In-Flight Fission of a 238U Beam at 345 MeV/nucleon

A search for new isotopes using in-flight fission of a 345 MeV/nucleon 238U beam has been carried out at the RI Beam Factory at the RIKEN Nishina Center. Fission fragments were analyzed and identified by using the superconducting in-flight separator BigRIPS. We observed 45 new neutron-rich isotopes: 71Mn, 73,74Fe, 76Co, 79Ni, 81,82Cu, 84,85Zn, 87Ga, 90Ge, 95Se, 98Br, 101Kr, 103Rb, 106,107Sr, 108,109Y, 111,112Zr, 114,115Nb, 115,116,117Mo, 119,120Tc, 121,122,123,124Ru, 123,124,125,126Rh, 127,128Pd, 133Cd, 138Sn, 140Sb, 143Te, 145I, 148Xe, and 152Ba

Adequacy of a compartment model for CMRO2_{2} quantitation using 15^{15}O-labeled oxygen and PET: a clearance measurement of 15^{15}O-radioactivity following intracarotid bolus injection of 15^{15}O-labeled oxyhemoglobin on Macaca fascicularis

We aimed at evaluating the adequacy of the commonly employed compartmental model for quantitation of cerebral metabolic rate of oxygen (CMRO2) using 15O-labeled oxygen (15O2) and positron emission tomography (PET). Sequential PET imaging was carried out on monkeys following slow bolus injection of blood samples containing 15O2–oxyhemoglobin (15O2–Hb), 15O-labeled water (H215O), and C15O-labeled hemoglobin (C15O–Hb) into the internal carotid artery (ICA). Clearance slopes were assessed in the middle cerebral artery territory of the injected hemisphere. The time–activity curves were bi-exponential for both 15O2–Hb and H215O. Single exponential fitting to the early (5 to 40 seconds) and late (80 to 240 seconds) periods after the peak was performed and the 15O2–Hb and H215O results were compared. It was found that a significant difference between the clearance rates of the 15O2–Hb and H215O injections is unlikely, which supports the mathematical model that is widely used to describe the kinetics of 15O2–Hb and H215O in cerebral tissues and is the basis of recent approaches to simultaneously assess CMRO2 and cerebral blood flow in a single PET session. However, it should be noted that more data are necessary to unequivocally confirm the result

System evaluation of automated production and inhalation of 15O-labeled gaseous radiopharmaceuticals for the rapid 15O-oxygen PET examinations

BACKGROUND:15O-oxygen inhalation PET is unique in its ability to provide fundamental information regarding cerebral hemodynamics and energy metabolism in man. However, the use of 15O-oxygen has been limited in a clinical environment largely attributed to logistical complexity, in relation to a long study period, and the need to produce and inhale three sets of radiopharmaceuticals. Despite the recent works that enabled shortening of the PET examination period, radiopharmaceutical production has still been a limiting factor. This study was aimed to evaluate a recently developed radiosynthesis/inhalation system that automatically supplies a series of 15O-labeled gaseous radiopharmaceuticals of C15O, 15O2, and C15O2 at short intervals.METHODS:The system consists of a radiosynthesizer which produces C15O, 15O2, and C15O2; an inhalation controller; and an inhalation/scavenging unit. All three parts are controlled by a common sequencer, enabling automated production and inhalation at intervals less than 4.5 min. The gas inhalation/scavenging unit controls to sequentially supply of qualified radiopharmaceuticals at given radioactivity for given periods at given intervals. The unit also scavenges effectively the non-inhaled radioactive gases. Performance and reproducibility are evaluated.RESULTS:Using an 15O-dedicated cyclotron with deuteron of 3.5 MeV at 40 μA, C15O, 15O2, and C15O2 were sequentially produced at a constant rate of 1400, 2400, and 2000 MBq/min, respectively. Each of radiopharmaceuticals were stably inhaled at < 4.5 min intervals with negligible contamination from the previous supply. The two-hole two-layered face mask with scavenging device minimized the gaseous radioactivity surrounding subject\u27s face, while maintaining the normocapnia during examination periods. Quantitative assessment of net administration doses could be assessed using a pair of radio-detectors at inlet and scavenging tubes, as 541 ± 149, 320 ± 103, 523 ± 137 MBq corresponding to 2-min supply of 2574 ± 255 MBq for C15O, and 1-min supply of 2220 ± 766 and 1763 ± 174 for 15O2 and C15O2, respectively.CONCLUSIONS:The present system allowed for automated production and inhalation of series of 15O-labeled radiopharmaceuticals as required in the rapid 15O-Oxygen PET protocol. The production and inhalation were reproducible and improved logistical complexity, and thus the use of 15O-oxygen might have become practically applicable in clinical environments

System evaluation of automated production and inhalation of 15O-labeled gaseous radiopharmaceuticals for the rapid 15O-oxygen PET examinations

Abstract Background 15O-oxygen inhalation PET is unique in its ability to provide fundamental information regarding cerebral hemodynamics and energy metabolism in man. However, the use of 15O-oxygen has been limited in a clinical environment largely attributed to logistical complexity, in relation to a long study period, and the need to produce and inhale three sets of radiopharmaceuticals. Despite the recent works that enabled shortening of the PET examination period, radiopharmaceutical production has still been a limiting factor. This study was aimed to evaluate a recently developed radiosynthesis/inhalation system that automatically supplies a series of 15O-labeled gaseous radiopharmaceuticals of C15O, 15O2, and C15O2 at short intervals. Methods The system consists of a radiosynthesizer which produces C15O, 15O2, and C15O2; an inhalation controller; and an inhalation/scavenging unit. All three parts are controlled by a common sequencer, enabling automated production and inhalation at intervals less than 4.5 min. The gas inhalation/scavenging unit controls to sequentially supply of qualified radiopharmaceuticals at given radioactivity for given periods at given intervals. The unit also scavenges effectively the non-inhaled radioactive gases. Performance and reproducibility are evaluated. Results Using an 15O-dedicated cyclotron with deuteron of 3.5 MeV at 40 μA, C15O, 15O2, and C15O2 were sequentially produced at a constant rate of 1400, 2400, and 2000 MBq/min, respectively. Each of radiopharmaceuticals were stably inhaled at < 4.5 min intervals with negligible contamination from the previous supply. The two-hole two-layered face mask with scavenging device minimized the gaseous radioactivity surrounding subject’s face, while maintaining the normocapnia during examination periods. Quantitative assessment of net administration doses could be assessed using a pair of radio-detectors at inlet and scavenging tubes, as 541 ± 149, 320 ± 103, 523 ± 137 MBq corresponding to 2-min supply of 2574 ± 255 MBq for C15O, and 1-min supply of 2220 ± 766 and 1763 ± 174 for 15O2 and C15O2, respectively. Conclusions The present system allowed for automated production and inhalation of series of 15O-labeled radiopharmaceuticals as required in the rapid 15O-Oxygen PET protocol. The production and inhalation were reproducible and improved logistical complexity, and thus the use of 15O-oxygen might have become practically applicable in clinical environments

Measurements of total reaction cross sections for 17Ne using a solid hydrogen target

We measured the energy dependence of the total reaction cross sections (σR) for the proton-drip-line nucleus, 17Ne, using a solid hydrogen target. We compared the experimental data with theoretical calculations using the Glauber model. We found that the theoretical cross sections overestimate the experimental ones in the low-energy region (∼100A MeV), whereas they significantly underestimate the experimental data in the intermediate-energy region (∼300-500A MeV). These trends are the same as those for σR for carbon–proton collisions, which were measured previously. We discuss several possibilities for resolving this discrepancy. This work demonstrates the necessity of additional careful investigations of the energy dependence of σR for various nuclei on proton targets in order to determine nuclear size properties precisely

Efficiency and timing performance of time-of-flight detector utilizing thin foils and crossed static electric and magnetic fields for mass measurements with Rare-RI Ring facility

We developed a time-of-flight (TOF) detector for mass measurements of rare radioactive isotopes (RIs) with a storage ring, called the Rare-RI Ring, in RIKEN. For successful mass measurements, a time resolution of less than 100 ps and a detection efficiency close to 100% are required. Additionally, the change of ion velocity in the detector should be as small as possible ( ). To satisfy these requirements, the TOF detector utilizes ion-induced secondary electrons emitted from a thin foil and the crossed static electric and magnetic fields to transport the electrons isochronously to the microchannel plate detectors. The TOF detector was tested in both offline test with an alpha source and online test with heavy ions. In the online test with 84Kr ions of 200 MeV/nucleon, a time resolution of 38.6(2) ps in sigma and a position-averaged detection efficiency of 95.2(2)% were achieved in the entire area of 45-mm-diameter aluminum-coated Mylar foil. This good performance is attributed to the electromagnetic field achieved, which is the strongest thus far for a detector with this design