[en] Tahlium-201 (201-Ti) is one the radioisotopes which can not be produced by nuclear reactor but has characteristic supporting ist application for diagnosis of cardiovascular disease. BATAN'S cyclotron, having proton bean energy of 25.5 MeV, is suitable for producing 201-Ti by nuclear reaction of 203-Ti (p,3n)201Pb....>201-Ti. Enriched 203 Ti up to 99% electroplated on target assembly surface was used as target material. The proton bean current coming to the target was around 30 to 46 uA whereas the beam extraction effiency was around 62 to 82%. The irradiation was carried out in about 5.8 to 8.0 hours. There are a lot of cyclotron operation variables affecting beam extraction efficiency, and the interdependence of the variable is not known, so that extraction efficiency fluctuates from one experiment to another. Fluctuations of 201-Ti production yield indicates that there are some critical stages in the processing sequence in which the 201-Ti is partly lost. Generally, thr resulting 201-Ti bulk solution is suitable to be formulated for radiopharmaceuticals preparation. For increasing cyclotron operational safety, a system to control the profile of beam collision on the preseptum is required. (authors). 16 refs.; 2 tabs.; 5 figs

[en] Thallium-201 is a radioisotope widely used for visualization of heart or cardiovascular diagnosis. It is generally produced by means of ²⁰³Tl(p,3n)²⁰¹Pb -->²⁰¹Tl reaction using enriched ²⁰³Tl (more than 95%) as target material. Since the enriched ²⁰³Tl is very expensive, the recovery of ²⁰³Tl from ²⁰¹Tl-processing waste is very important. For this reason, a high accuracy and good precision method for Tl measurement is required. Having a single absorbance maximum at 214 nm which is stable up 24 hours post preparation, it is expected that Tl can be quantitatively determined by spectrophotometry in the UV region. The chemical matrices in the ²⁰¹Tl-processing waste were separated by hydroxide precipitation, stipping extraction and charcoal adsorption techniques. The linearity of the absorbance standard curve is given by regression line A = 0.0013 + 0.0223C with C is concentration in mg/dm³. The regression coefficient was found to be 0.9999. Evaluation using simulated waste solutions and ²⁰¹Tl-processing waste samples showed that both the accuracy and the precision, in terms of repeatability, of the measurement were high. (author)

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