摘要:

A wide‐range self‐contained amplifier and charge‐to‐time converter module for energy detectors was designed, prototyped and built. The charge‐to‐time conversion is accomplished using a LeCroy MQT300L integrated circuit and a switch is provided to convert either positive or negative charge inputs. This new module replaces the charge preamplifier, shaping amplifier, fast amplifier, CFD, and level discriminator normally found in a traditional NIM‐based system and can be placed close to the detector. It is powered from a small, dedicated AC‐DC power supply. The module is self‐triggering and provides an ECL timing signal from an onboard constant fraction discriminator. The outputs are routed to a standard RJ45 connector and conditioned for long cabling. Details of module linearity and timing resolution will be discussed. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1619891

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Recent progress of cyclotron ion beam development for applications in materials science and biotechnology at the ion‐irradiation research facility TIARA of the Japan Atomic Energy Research Institute(JAERI) is overviewed. The AVF cyclotron in TIARA can accelerate protons and heavy ions up to 90 MeV and 27.5 MeV/n, respectively. In order to conform to the requirement of a reliable tuning of microbeam formation, the cyclotron beam current has been stabilized by controlling the temperature of the magnet yoke and pole within +/−0.5° and hence by decreasing the variation of the magnetic field &Dgr;B/B below 10−5. A heavy ion microbeam with energy of hundreds MeV is a significantly useful probe for researches on biofunctional elucidation in biotechnology. Production of the microbeam with spot size as small as 1&mgr;m by quadrupole lenses requires the energy spread of the beam &Dgr;E/E < 2 × 10−4. In order to minimize the energy spread of the cyclotron beam, the fifth‐harmonic voltage waveform has been successfully superposed on the fundamental one to make energy gain uniform. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1619892

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The University of Texas M.D. Anderson Cancer Center (MDACC), in partnership with Sanders Morris Harris Inc., a Texas‐based investment banking firm, and The Styles Company, a developer and manager of hospitals and healthcare facilities, is building a proton therapy facility near the MDACC main complex at the Texas Medical Center in Houston, Texas USA. The MDACC Proton Therapy Center will be a freestanding, investor‐owned radiation oncology center offering state‐of‐the‐art proton beam therapy. The facility will have four treatment rooms: three rooms will have rotating, isocentric gantries and the fourth treatment room will have capabilities for both large and small field (e.g. ocular melanoma) treatments using horizontal beam lines. There will be an additional horizontal beam room dedicated to physics research and development, radiation biology research, and outside users who wish to conduct experiments using proton beams. The first two gantries will each be initially equipped with a passive scattering nozzle while the third gantry will have a magnetically swept pencil beam scanning nozzle. The latter will include enhancements to the treatment control system that will allow for the delivery of proton intensity modulation treatments. The proton accelerator will be a 250 MeV zero‐gradient synchrotron with a slow extraction system. The facility is expected to open for patient treatments in the autumn of 2005. It is anticipated that 675 patients will be treated during the first full year of operation, while full capacity, reached in the fifth year of operation, will be approximately 3,400 patients per year. Treatments will be given up to 2‐shifts per day and 6 days per week. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1619893

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Dose distributions produced by using proton and ion beams in radiation therapy conform closely to the target volume maximizing the sparing of adjacent normal tissues and sensitive structures. Worldwide, through 2001, over 30,000 patients have been treated with proton beams and over 3,500 with ion beams. In 2002, there are 21 operating proton therapy facilities, including several hospital‐based dedicated facilities. Seven of these facilities are limited to treating eye tumors only. Carbon ions are available at two facilities in Japan and one in Germany. All existing centers use either a cyclotron or a synchrotron and several facilities have one gantry or more to provide beams at any angle to the patient. For several treatment sites, there are good long‐term follow‐up results, increasing the interest worldwide in having proton or ion beams more readily available. As a result many new facilities are under construction or being planned and some existing facilities are being upgraded. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1619894

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The first proton therapy patient was successfully treated for astrocytoma using a modified nuclear experimentation beam line and in‐house treatment planning in 1993. In 1998, IUCF constructed an eye treatment clinic, and conducted a phase III clinical trial investigating proton radiation treatment of AMD. Treatment was planned using Eyeplan modified to match the IUCF beam characteristics. MPRI was conceptualized in 1996 by a consortium of physicians and physicists. Reconfiguration began in 2000; construction of the achromatic trunk line began in 2001, followed by manufacture of 4 energy selection lines and two fixed horizontal beam treatment lines. Two isocentric, rotational gantries will be installed following completion of the horizontal beam lines. A fifth line will supply the full‐time radiation effects research station. Standard proton delivery out of the main stage is specified at 500 nA of 205 MeV. Clinic construction began in April, 2002 and will be completed by mid‐December. Design, construction and operation of these proton facilities have been accomplished by the proton therapy group at IUCF. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1619895

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Fluorine‐18 is currently the most widely used radioisotope in PET imaging. While much attention has been paid in recent years to production methods from18O(p,n)18F, the current work revisits production techniques using non‐enriched neon targets and the20Ne(d,&agr;)18F reaction. While this reaction was originally pursued, and ultimately replaced by the higher yielding18O reactions, there is an opportunity using high current low‐energy deuteron accelerators and the inherent simplicity of gas targetry to provide viable alternatives to the costly18O water target systems.18F production systems have been developed for the gas‐phase20Ne(d,&agr;)18F reaction with deuterons from a 3MV NEC 9SDH‐2 electrostatic tandem accelerator. High power target systems allowing for irradiation in excess of 100uA provided [18F]F2yields to 86&percent; of the theoretical maximum, and [18F]F−yields with a wash‐off system of 80&percent; of the maximum. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1619896

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

For more than 10 years Radium Institute is producing radiopharmaceuticals for St. Petersburg (Russia) hospitals. We have developed technologies for sodium iodide, sodium iodohippurate, MIBG and BMIPP, labeled by iodine‐123, and gallium‐67 citrate. Radionuclidic purity of 99,98&percent; is reached for radiopharmaceuticals labeled by iodine‐123. Radionuclidic purity is over 99.9&percent; for gallium‐67 citrate on the date of delivery. Radiochemical purity of 95&percent; and more is reached through the application of appropriate technologies for each RPH. It takes no longer than 4 hours for all technologies. Over 150,000 patients were investigated. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1619897

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

This work describes the production of10C(t12 = 19 s)from an enriched10B2O3target using a CTI RDS‐112 11 MeV proton cyclotron. Proton beam heating is used to raise the target to a molten state (∼ 1300 °C), enabling the activity to diffuse to the surface of the melt. An infrared thermocouple monitors the melt temperature. Helium sweep gas then transports the activity to flow‐through chemistry processing for human inhalation of10CO2for blood flow imaging with Positron Emission Tomography. The temperature‐related diffusion of activity out of the white‐hot molten glass target is discussed. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1619898

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

A gridded‐niobium target was constructed for the improvement of routine [18F]‐fluorine production from18O‐enriched water on a CTI RDS 112 cyclotron. Niobium was chosen for its inertness and excellent thermal properties. The target volume consists of a 400&mgr;L (active volume) niobium chamber mounted with a single entrance foil supported against an array of 3mm hexagonal holes with 0.25mm aluminum septa, machined by EDM. The target operates at high beam currents and elevated pressures and temperatures with significant reductions in maintenance intervals. Several diagnostic tools such as autoradiography, activation, and neutron logging optimize the performance and yield of the target. Entrance foils including Havar and Nb are used to assess the [18F] chemical compatibility, with FDG synthesis as the test reaction. The gridded, single‐foiled niobium target chamber appears to be an improvement compared to a standard double‐foiled helium cooled water target used with RDS cyclotrons. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1619899

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Absorbed‐dose images and depth‐dose profiles have been measured in a tissue‐equivalent phantom exposed to an epithermal neutron beam designed for neutron capture therapy. The spatial distribution of absorbed dose has been measured by means of gel dosimeters, imaged with optical analysis. From differential measurements with gels having different isotopic composition, the contributions of all the components of the neutron field have been separated. This separation is important, owing to the different biological effectiveness of the various kinds of emitted radiation. The doses coming from the reactions1H(n,&ggr;)2H and14N(n,p)14C and the fast‐neutron dose have been imaged. Moreover, a volume simulating a tumour with accumulation of10B and/or157Gd has been incorporated in the phantom and the doses due to the reactions with such isotopes have been imaged and profiled too. The results have been compared with those obtained with other experimental techniques and the agreement is very satisfactory. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1619900

出版商:AIP    

年代:1903

数据来源: AIP