ABSTRACT
The SnO268Ge/68Ga generator system is widely used in medical imaging to provide a regular supply of the radionuclide 68Ga (T½ = 68.3 min) for positron emission tomography (PET). These generators are also used to supply 68Ga for the fabrication of tracer particles for application in positron emission particle tracking (PEPT). The tracer particles are fabricated by radiolabelling ion exchange resins such as Purolite NRW100 with 68Ga; however, contaminants from the degradation of the SnO2 column over time interfere with the uptake of 68Ga. The major contaminants are Zn(II), Fe(III) and Sn(IV) with 68Ge (IV) being eluted from the column as it degrades. This paper describes an improved method to purify the 68Ga supply using an Amberchrom CG-71m absorption resin column integrated into a newly designed separation panel. This method reduces the amount of Zn(II) and Fe(III) in the 68Ga eluate and improves the radiolabelling performance by more than 10% when compared to the un-purified product. The method can extend the life-span of the generator by several months.
ABSTRACT
Within the framework of the EURADOS Working Group 11, a comparison of passive neutron dosemeters in high-energy neutron fields was organised in 2011. The aim of the exercise was to evaluate the response of poly-allyl-glycol-carbonate neutron dosemeters from various European dosimetry laboratories to high-energy neutron fields. Irradiations were performed at the iThemba LABS facility in South Africa with neutrons having energies up to 66 and 100 MeV.
Subject(s)
Neutrons , Polymers/chemistry , Radiation Monitoring/instrumentation , Radiation Protection/instrumentation , Air , Aircraft , Calibration , Carbonates/chemistry , Cosmic Radiation , Cyclotrons , Europe , Humans , Phantoms, Imaging , Radiation Dosage , Radiation Monitoring/methods , Radiation Protection/methods , Scintillation Counting , South Africa , SpacecraftABSTRACT
THE QUALITY STANDARDS OF THE FRENCH SOCIETY OF VASCULAR MEDICINE FOR THE ULTRASONOGRAPHIC ASSESSMENT OF VASCULAR MALFORMATIONS ARE BASED ON THE TWO FOLLOWING REQUIREMENTS: Technical know-how: mastering the use of ultrasound devices and the method of examination. Medical know-how: ability to adapt the methods and scope of the examination to its clinical indication and purpose, and to rationally analyze and interpret its results. AIMS OF THE QUALITY STANDARDS: To describe an optimal method of examination in relation to the clinical question and hypothesis. To achieve consistent practice, methods, glossary, and reporting. To provide good practice reference points, and promote a high-quality process. ITEMS OF THE QUALITY STANDARDS: The three levels of examination; their clinical indications and goals. The reference standard examination (level 2), its variants according to clinical needs. The minimal content of the examination report; the letter to the referring physician (synthesis, conclusion and proposal for further investigation and/or therapeutic management). Commented glossary (anatomy, hemodynamics, semiology). Technical bases. Settings and use of ultrasound devices. Here, we discuss the methods of using ultrasonography for the assessment of peripheral vascular malformations and tumors.
Subject(s)
Quality Assurance, Health Care , Ultrasonography, Doppler/standards , Vascular Malformations/diagnostic imaging , Vascular Neoplasms/diagnostic imaging , Arm/blood supply , Arteries/diagnostic imaging , Hemangioma/diagnostic imaging , Humans , Leg/blood supply , Lymphangioma/diagnostic imaging , Physical Examination/methods , Physical Examination/standards , Ultrasonography, Doppler/instrumentation , Ultrasonography, Doppler/methods , Ultrasonography, Doppler, Color/methods , Ultrasonography, Doppler, Color/standards , Ultrasonography, Doppler, Pulsed/methods , Ultrasonography, Doppler, Pulsed/standards , Ultrasonography, Interventional/standards , Vascular Malformations/classification , Veins/diagnostic imaging , Venous Thrombosis/diagnostic imagingABSTRACT
A compact liquid organic neutron spectrometer based on a single NE213 liquid scintillator (5 cm diameter x 5 cm) is described. The spectrometer is designed to measure neutron fluence spectra over the energy range 2-200 MeV and is suitable for use in neutron fields having any type of time structure. Neutron fluence spectra are obtained from measurements of two-parameter distributions (counts versus pulse-height and pulse shape) using the Bayesian unfolding code MAXED. Calibration and test measurements made using a pulsed neutron beam with a continuous energy spectrum are described and the application of the spectrometer to radiation dose measurements is discussed.
Subject(s)
Neutrons , Organic Chemicals/chemistry , Organic Chemicals/radiation effects , Radiometry/instrumentation , Radiometry/methods , Spectrum Analysis/instrumentation , Equipment Design , Equipment Failure Analysis , Miniaturization , Radiation Dosage , Reproducibility of Results , Sensitivity and Specificity , SolutionsABSTRACT
A NE230 deuterated liquid scintillator detector (25 mm diameter x 25 mm) has been used to investigate neutron energy spectra as a function of position in a water phantom under irradiation by a quasi-monoenergetic 64 MeV neutron beam. Neutron energy spectra are obtained from measurements of pulse height spectra by the NE230 detector using the Bayesian unfolding code MAXED. The experimentally measured energy spectra are compared with spectra calculated by Monte Carlo simulation using the code MCNPX.
Subject(s)
Neutrons , Radiation Monitoring/instrumentation , Radiation Protection/instrumentation , Scintillation Counting/instrumentation , Spectrum Analysis/instrumentation , Water/chemistry , Equipment Design , Equipment Failure Analysis , Radiation Dosage , Radiation Monitoring/methods , Radiation Protection/methods , Reproducibility of Results , Scattering, Radiation , Scintillation Counting/methods , Sensitivity and Specificity , Spectrum Analysis/methodsABSTRACT
Well-characterised neutron fields are a prerequisite for the investigation of neutron detectors. Partly in collaboration with external partners, the PTB neutron metrology group makes available for other users neutron reference fields covering the full energy range from thermal to 200 MeV. The specification of the neutron fluence in these beams is traceable to primary standard cross sections.
Subject(s)
Algorithms , Equipment Failure Analysis/standards , Models, Chemical , Neutrons , Radiation Protection/standards , Radiometry/methods , Radiometry/standards , Computer Simulation , Equipment Failure Analysis/methods , Germany , Internationality , Radiation Dosage , Radiation Protection/methods , Radioisotopes/analysis , Reference Standards , Scattering, RadiationABSTRACT
A stacked scintillator neutron spectrometer (S3N) consisting of three slabs of liquid organic scintillator is described. A pulsed beam providing a broad spectrum of neutron energies is used to determine the detection efficiency of the spectrometer as a function of incident neutron energy and to measure the pulse height response matrix of the system. Neutron spectra can then be determined for beams with any kind of time structure by unfolding pulse height spectra measured by the S3N. Examples of fluence spectrum measurements in the energy range 20-150 MeV are presented.
Subject(s)
Neutrons , Radioisotopes/analysis , Scintillation Counting/instrumentation , Scintillation Counting/methods , Spectrum Analysis/instrumentation , Spectrum Analysis/standards , Calibration/standards , Guidelines as Topic , Linear Energy Transfer , Reference Standards , Reproducibility of Results , Scattering, Radiation , Scintillation Counting/standards , Sensitivity and Specificity , South Africa , Spectrum Analysis/methodsABSTRACT
Four methods for employing neutrons to detect abandoned small anti-personnel landmines are presented and discussed. The techniques used are based on measurements of effects due to the scattering of neutrons on the hydrogen content of the landmine.
Subject(s)
Blast Injuries/prevention & control , Neutrons , Computer Simulation , Humans , Hydrogen/chemistry , Monte Carlo Method , Scattering, Radiation , WarfareABSTRACT
OBJECTIVE: To evaluate prospectively the laparoscopic surgery for giant hiatal hernias treated by fundoplication and hiatal prosthesis. PATIENTS AND METHODS: Ten patients were included in this study. Surgical technic included the dissection of oesophageal hiatus, the sac excision and the dissection of the abdominal oesophagus to obtain a physiological length. The decision criterion for a prosthesis was the hiatus oesophagus diameter of 5 cm or more. The crura were closed and the hiatus was reinforce by a prosthesis of 15 x 15 cm. All patients underwent a fundoplication whether partial or complete. RESULTS: Eight patients had a type III hernia, and 2 had a type II. The mean size for the hiatus was 6.5 cm (5.5-8). Eight patients underwent a total fundoplicature and 2 a partial one. The prosthesis was made of polypropylene in 5 cases. Average operating time was 182 min (78-240). One patient had postoperative morbidity, with gastroplagia which resolved. There was no mortality. Mean hospitalisation duration was 7.7 days (5-12). No one case of recurrence have been noticed after a mean follow-up of 24 months (8-40). CONCLUSION: It appears that the large size hiatal hernia (more than 5 cm) can be treated with good results by using a prosthesis during laparoscopic fundoplication.
Subject(s)
Fundoplication/methods , Hernia, Hiatal/surgery , Laparoscopy/methods , Prosthesis Implantation , Aged , Female , Hernia, Hiatal/pathology , Humans , Length of Stay , Male , Middle Aged , Morbidity , Prospective Studies , Recurrence , Surgical Mesh , Treatment OutcomeABSTRACT
Laparoscopic treatment of inguinal hernias has expanded rapidly during the last decade. Several studies have evaluated the early results of this technique, and the rate of recurrence was estimated less than 5% with a range from 0.5% to 10%. The long-term recurrence after such treatment is still not well known. This study reports the 2 year follow-up of laparoscopic treatment of 236 inguinal hernias (220 patients) from January 1996 to December 1997. All patients were contacted by telephone, 196 (90%) (193 men and 3 women) were examined by a senior surgeon. The average time from operation to examination was 34 months (range 20-42 months). We observed a 15% recurrence rate (35 hernias in 34 patients) of which 5% (12 cases) were symptomatic but 10% (23 cases) were totally asymptomatic and diagnosed on clinical examination. The postoperative inguinal haematoma and the physical activity of the patients seem to predispose the recurrence. Chronic pain was rarely observed in this study.
Subject(s)
Hernia, Inguinal/surgery , Adult , Aged , Aged, 80 and over , Female , Humans , Laparoscopy , Male , Middle Aged , Recurrence , Time FactorsSubject(s)
Models, Structural , Neutron Capture Therapy , Gamma Rays , Humans , Neutrons , Radiotherapy DosageABSTRACT
High-resolution neutron fluence spectra have been measured in the National Accelerator Centre's p(66)/Be(40) neutron therapy beam by the pulsed-beam time-of-flight method. ICRU muscle kerma spectra have been derived from the fluence spectra. Spectral changes resulting from different irradiation conditions have been quantified in terms of the average neutron energy and the fractional low-energy (< 16 MeV) contribution. The changes observed with different thicknesses of polyethylene filtration are consistent with changes in quality parameters determined in biological and microdosimetric experiments. The dosimetry parameters (KtissueA150) N and (Wgas) N calculated for the measured spectra agree with the values recommended in the neutron dosimetry protocol. The shapes of the present fluence spectra differ from previous measurements of p(> 40)/Be spectra. In particular, they differ significantly from the spectrum measured by recoil techniques in an identical neutron therapy unit at the Clatterbridge Hospital, UK. The reasons for the difference are not known.
