[en] A detailed description of the Pelletron accelerator system at the Department of Physics, University of Lund, Sweden, is given. The construction, running experience, operating instructions, and suggestions about maintenance are presented. The experimental setups, gashandling equipment and other facilities constructed at the laboratory are described. (author)

[en] A detailed description of a Nielsen type heavy ion source constructed at the laboratory to be used at the accelerator is given. Results from tests with Li, B and P ions are presented. Suggestions for further developments of the ion source are given. An operating instruction for the ion source is included. (Authors)

[en] Several improvements that have been implemented in the Pelletron system are described. The main components are protective automatically closing valves at each end of the accelerator tank, pick-up wheels and corona point supports of a new design, and valves in the stripper housing. These modifications result in improved operation reliability and a minimum of service interruptions. (orig.)

[en] C-14, a pure low-energetic beta-emitter, is produced through various nuclear reactions in nuclear power plants. Some of this C-14 is air-borne and is transported via the ventilation system through the stack of the power station and is integrated in living matter in the surroundings of the plant. The long half-life of the isotope (T1/2=5730 years) and the biological importance of carbon may lead to a not negligible contribution of the radiation dose for those living in the neighbourhood of nuclear power plants. C-14 has earlier been measured radiometrically with mainly two different methods, using proportional counters or liquid scintillators. In this report a new method is described, using an accelerator based technique. accelerator mass spectrometry (AMS). This technique has at least three advantages over the radiometrical methods. It requires only a few litres of gas per sample, which is 100-1000 times less compared to the radiometrical methods. It is insensitive to the beta and gamma rays from other radioactive isotopes in the stack air. The measuring time with AMS, about 20 minutes per sample, is considerably shorter compared to the radiometrical methods, which demand several hours per sample. The integrity of the AMS method is high and it might be convenient for regulatory supervision. (22 refs.)

[en] To describe the normal MR appearance after cholecystectomy and the findings in patients with postoperative complications using fast pulse sequences in abdominal MR imaging. Material and methods: In a prospective study of 119 patients, 64 were examined with MR after cholecystectomy. In total, 56 patients with uncomplicated cholecystectomy were examined with MR 1-5 days (mean 1.6 days) after cholecystectomy. Nine patients had an abdominal postoperative complication and 8 of these were examined with MR after the complication commenced 1-12 days after the cholecystectomy. Results: Oedema in the gallbladder fossa was the only finding in 39 patients (61%), all with uneventful recovery. Small fluid collections in an area consistent with the gallbladder fossa were seen in 9/64 (14%) patients, of which 3 had surgical complications: 1 bleeding and 2 bile duct leakage. Twenty-two (34%) patients had small locally situated fluid collections adjacent to the liver, 14 were uneventful and 8 showed postoperative surgical complications. Seven patients had fluid in the rest of the abdomen of which 5 had surgical complications; 4 due to bile duct leakage and 1 acute pancreatitis. One patient had a postoperative bleeding not seen on MR images. Conclusion: MR is very sensitive in detecting fluid collections. Early MR findings following cholecystectomy are normally only subtle changes, mainly in the gallbladder fossa. Fluid collections diagnosed elsewhere than in the gallbladder fossa usually indicate a surgical complication and a surgical complication is unlikely if MR fails to show a fluid collection

[en] Purpose: The diagnostic value and cost-efficiency of MR imaging were compared with US before endoscopic retrograde cholangiopancreatography (ERCP) in patients with clinically suspected biliary tract disease. Material and Methods: In a prospective study of 219 patients, 85 were examined with both MR and US before ERCP. Results: To find the correct diagnosis in the jaundiced patients the sensitivity of US, MR and ERCP was 53%, 93%, and 89%, respectively. In the patients with abdominal upper quadrant pain and normal serum bilirubin, the sensitivity of US, MR and ERCP was 50%, 100% and 70%, respectively. Examination with MR costs four times more than US. Screening with US and supplemental MR in non-diagnostic cases would cost 80% of the total amount compared to screening with MR only. Conclusion: MR had a higher sensitivity than US for diagnosing biliary tract disease and MR was superior to US in visualising stones in the common bile duct and in diagnosing the cause of cholestasis. However, screening with US and supplemental MR in non-diagnostic cases is at present most cost-effective. With increased accessibility and slightly lower costs, MR will probably replace US as screening method in patients with suspected biliary tract disease

[en] Purpose: The diagnostic value of fast pulse sequences in MR imaging was compared with US in patients with clinically suspected acute cholecystitis. Material and Methods: In a prospective study of 94 patients, 35 were examined with both MR and US within 24 h. Results: MR diagnoses were acute cholecystitis in 23, gallbladder and common bile duct stones in 3, other pathologic conditions of the abdomen in 7 and normal in 2 patients. US diagnoses were acute cholecystitis in 17, gallbladder stones in 8, other pathologic conditions of the abdomen in 2, normal in 5 and non-conclusive in 3 patients. Conclusion: MR has a higher sensitivity than US for diagnosing acute cholecystitis and, with increased accessibility (may be the first imaging method)

[en] Purpose: To study the appearance of bile in clinical MR cholangiopancreatography (MRCP) with special reference to its chemical and physical properties. Material and Methods: Gallbladder bile was collected during surgery from 38 patients and studied with respect to chemical constituents. The relaxation rates 1/T1 and 1/T2 of bile were also determined in vitro. In 16 of these 38 patients, abdominal imaging was performed using MRCP as well as T1-weighted GE sequences. Results: For 9 of the 13 chemical parameters studied, a positive significant correlation with 1/T1 as well as 1/T2 was found. The median relaxation rates 1/T1 and 1/T2 were 0.76 and 1.48/s, respectively. The corresponding ranges were 0.38-3.13/s and 0.70-5.75/s, respectively. On the MRCP images a few patients showed gallbladder of poor visibility due to low signal-to-noise ratio. This coincided with a high relaxation rate 1/T2 of bile. On the T1-weighted GE sequences a few patients showed hyperintense gallbladder relative to liver, coinciding with high relaxation rates 1/T1 of bile. Conclusion: Bile was found to show a large interindividual variation with respect to relaxation rates 1/T1 and 1/T2. The relaxation rates increased with increasing amounts of substances in the bile. For some patients (11%) MRCP imaging is unsuccessful due to high relaxation rate of bile

[en] Routine production of [¹⁸F]fluoride has been carried out by 6 MeV proton irradiation of H₂¹⁸O water using a small-volume silver target vessel. By optimizing the target design, a 120 min irradiation of 600 μl 97% enriched [¹⁸O]H₂O at a beam current of 10 μA gives a practical yield of 5700±80 MBq (154±2 mCi). The produced [¹⁸F]fluoride has been used for no-carrier-added synthesis of 2-¹⁸FDG. (orig.)

[en] Accelerator mass spectrometry (AMS) requires ion sources delivering intense negative ion beams of high stability. At the Lund 3 MV Pelletron tandem accelerator a new Cs-sputtering source has therefore been constructed and installed. The source is equipped with a mechanism for automatically cracking the cesium glass ampoule inside the oven when the source is evacuated. The source is also equipped with a multiple sample holder which permits on-line sample changing without disrupting the operation of the electrostatic accelerator. In order to maximise the negative ion beam current the sample holder has a mechanism for moving the sample relative to the cesium beam. By doing this the lifetime of the samples can be increased. (orig.)