[en] We present the complete calculation of the transverse momentum distribution for the decay b → sγ. The contributions of the leading operator O₇ are computed: infrared logarithms are resummed with next-to-leading accuracy according to usual techniques of resummation. Non logarithmic terms are evaluated to O(α_s) by calculating one loop diagrams

[en] For an optimal tuning of the radiation protection planning, a Monte Carlo model using the MCNPX code has been built, allowing an accurate estimate of the spectrometric and geometrical characteristics of photoneutrons generated by a Varian TrueBeam Stx© medical linear accelerator. We considered in our study a device working at the reference energy for clinical applications of 15 MV, stemmed from a Varian Clinac©2100 modeled starting from data collected thanks to several papers available in the literature. The model results were compared with neutron and photon dose measurements inside and outside the bunker hosting the accelerator obtaining a complete dose map. Normalized neutron fluences were tallied in different positions at the patient plane and at different depths. A sensitivity analysis with respect to the flattening filter material were performed to enlighten aspects that could influence the photoneutron production. - Highlights: • A Monte Carlo model of a medical LINAC and of the hosting bunker is presented. • The photoneutrons production is analysed. • The related radiation protection issues have been considered.

[en] The high cost of virgin ¹⁸O-enriched water has forced many researchers to study methods to purify and recycle enriched water after the first irradiation for the production of radiopharmaceuticals. In our study, [¹⁸O]H₂O was purified by ozonolysis and distillation. Analyses showed a large decrease in impurities after this treatment. The purification procedure was carried out after the production of 94 batches of [¹⁸F]-FDG, which were manufactured using a GE Minitrace cyclotron and a GE Mx TracerLab synthesizer. Saturation yields after bombardment, using virgin and re-purified water were, respectively, 2864±204 MBq/μA and 2727±167 MBq/μA, a decrease of 5.5%. The decrease in [¹⁸F]-FDG yield, from 67.2±0.7% to 65.5±0.9%, can be ascribed to the irradiation step only