B. Király

Excitation functions of 3He- and α-particle induced nuclear reactions on natSb for production of medically relevant 123I and 124I radioisotopes

Excitation functions were measured using the stacked foil irradiation technique from threshold energies to 28 MeV for (3)He- and to 21 MeV for alpha-particle induced nuclear reactions on natural antimony leading to the formation of (121,123,124)I radioisotopes. The measured excitation functions were compared with the contradicting results of the earlier investigations found in the literature and with the curves predicted by the ALICE-IPPE and EMPIRE-II codes. Integral yields were also calculated and compared with the experimental thick target yields reported in the literature.

Investigation of alternative production routes of 99mTc: Deuteron induced reactions on 100Mo

Activation cross sections of deuteron induced nuclear reactions on enriched (100)Mo have been studied up to 50 MeV using the stacked foil irradiation technique and gamma spectroscopy. The excitation functions for production of (99m)Tc, (ind99)Mo, (ind98m)Nb, (ind97mg)Nb radioisotopes were measured for the first time and compared with the results of the ALICE-D, EMPIRE-D and TALYS codes. Production possibilities of the medically important (99m)Tc are discussed.

Experimental study of the excitation functions of proton induced nuclear reactions on 167Er for production of medically relevant 167Tm

(167)Tm (T(1/2)=9.25d) is a candidate radioisotope for medical therapy and diagnostics due to its Auger-electron and low-energy X- and gamma-ray emission. Excitation functions of the (167)Er(p,n)(167)Tm reaction and (168)Er(p,n)(168)Tm, (167)Er(p,2n)(166)Tm, (166)Er(p,2n)(165)Tm disturbing reactions were measured up to 15MeV by using the stacked foil irradiation technique and gamma-ray spectroscopy. The measured excitation functions agree well with the results of ALICE-IPPE, EMPIRE-II and TALYS nuclear reaction model codes. The thick target yield of (167)Tm in the 15-8MeV energy range is 6.9MBq/microAh. A short comparison of charged particle production routes of (167)Tm is given.

New cross-sections for production of 103Pd; review of charged particle production routes

Production cross-sections of (103)Ag obtained by irradiating (nat)Pd and (nat)Cd with 70 MeV protons are presented and compared with ALICE-IPPE model calculations. Production of (103)Ag is of interest for the generation of (103)Pd widely used in brachytherapy. The investigated energy range of the (103)Rh(d,2n)(103)Pd reaction was extended up to 40 MeV and the results were compared with the curves of ALICE-IPPE, EMPIRE-II and GNASH theoretical codes. Thick target yields were calculated. An overview and analysis of the most important charged particle induced production routes of (103)Pd is presented. An explanation of the apparent discrepancy in the activity measurements for (103)Rh based on X- or gamma-ray is given.

Cross section measurements of the 131Xe(p,n) reaction for production of the therapeutic radionuclide 131Cs

(131)Cs is an X-ray emitter radioisotope gaining interest in prostate brachytherapy. It is generally produced via the (130)Ba(n,gamma)(131)Ba-->(131)Cs process in thermal-flux reactors. Here we investigate its cyclotron production possibilities. Excitation function of the (131)Xe(p,n)(131)Cs reaction was measured up to 35MeV using the stacked gascell technique and high-resolution X-ray spectrometry. The experimental data were compared with results of the ALICE-IPPE and EMPIRE-II codes and curves taken from the PADF and TENDL database. The calculated integral yield was 17MBq/microAh in the energy range E(p)=20-->7MeV. Comparison of cyclotron and reactor production routes was given.

Investigation of activation cross sections of deuteron induced reactions on indium up to 40MeV for production of a 113Sn/113mIn generator

(113)Sn (115.09 d) is the parent nuclide of the (113)Sn/(113m)In generator system. (113m)In (99.476 min) is used in diagnostic nuclear medicine and as an Auger-electron emitter is a candidate for internal radiotherapy. Excitation functions of the (nat)In(d,x) (113 mg)Sn, (116 m)In, (ind115m)In, (114m)In, (ind113m)In, (cum111)In, (115g)Cd,(111m)Cd reactions were measured up to 40 MeV for the first time. The experimental results were compared with the curves calculated with the ALICE-D and EMPIRE-D theoretical model codes and curves given in the EAF-2007 and TENDL-2009 databases. Thick target yields, impurity levels and specific activities for the optimal energy range were deduced and compared with the same parameters of other charged particle production routes of (113)Sn.

Investigation of production of the therapeutic radioisotope 165Er by proton induced reactions on erbium in comparison with other production routes

The excitation function of the (nat)Er(p,xn)(165)Tm reaction resulting in production of (165)Er was measured up to 70 MeV by activation of stacked foils practically for the first time. The theoretical interpretation is based on the results of the ALICE-IPPE and EMPIRE-II codes. From the measured experimental cross section data integral production yield was calculated and compared with experimental integral yield data reported in the literature. Different production routes of the therapeutic radioisotope (165)Er were compared.

Study of excitation functions of alpha-particle induced nuclear reactions on holmium for 167Tm production.

(167)Tm is a candidate radioisotope for both nuclear medicine diagnostics and therapy due to its emitted Auger-electrons, low energy X- and gamma-rays. In the frame of a systematic study of excitation functions for production of medically relevant radioisotopes by charged particle induced reactions on rare earths, the (165)Ho(alpha,2n)(167)Tm reaction and the (165)Ho(alpha,n)(168)Tm, (165)Ho(alpha,3n)(166)Tm, (165)Ho(alpha,4n)(165)Tm side reactions were measured up to 40 MeV by the stacked foil irradiation technique and gamma-ray spectroscopy. The measured results were compared to the ALICE-IPPE and EMPIRE-II theoretical curves. Thick target yields, impurity levels and specific activities were deduced and compared with the same parameters for other charged particle production routes of (167)Tm.

A Promising Future: Comparable Imaging Capability of MRI-Compatible Silicon Photomultiplier and Conventional Photosensor Preclinical PET Systems

We recently completed construction of a small-animal PET system—the MiniPET-3—that uses state-of-the-art silicon photomultiplier (SiPM) photosensors, making possible dual-modality imaging with MRI. In this article, we compare the MiniPET-3 with the MiniPET-2, a system with the same crystal geometry but conventional photomultiplier tubes (PMTs). Methods: The standard measurements proposed by the National Electrical Manufacturers Association NU 4 protocols were performed on both systems. These measurements included spatial resolution, system sensitivity, energy resolution, counting rate performance, scatter fraction, spillover ratio for air and water, recovery coefficient, and image uniformity. The energy windows were set to 350–650 keV on the MiniPET-2 and 360–662 keV on the MiniPET-3. Results: Spatial resolution was approximately 17% better on average for the MiniPET-3 than the MiniPET-2. The systems performed similarly in terms of peak absolute sensitivity (∼1.37%), spillover ratio for air (∼0.15), spillover ratio for water (∼0.25), and recovery coefficient (∼0.33, 0.59, 0.81, 0.89, and 0.94). Uniformity was 5.59% for the MiniPET-2 and 6.49% for the MiniPET-3. Minor differences were found in scatter fraction. With the ratlike phantom, the peak noise-equivalent counting rate was 14 kcps on the MiniPET-2 but 24 kcps on the MiniPET-3. However, with the mouselike phantom, these values were 55 and 91 kcps, respectively. The optimal coincidence time window was 6 ns for the MiniPET-2 and 8 ns for the MiniPET-3. Conclusion: Images obtained with the SiPM-based MiniPET-3 small-animal PET system are similar in quality to those obtained with the conventional PMT-based MiniPET-2.

Study of activation cross sections of proton induced reactions on barium: Production of 131Ba 131Cs

In the frame of a systematic study of charged particle production routes of the therapeutic radioisotope (131)Cs, excitation functions of the (nat)Ba(p,x)(135,132mg)La, (ind135m,cum133m,cum133mg,cum131mg)Ba and (136mg,134mg,132,cum129)Cs reactions were measured in the 30-70 MeV energy range using stacked foil irradiation technique, activation method and gamma spectroscopy. Comparisons with new results of the ALICE-IPPE and EMPIRE-II codes and with existing data obtained with TALYS code are shown. From the measured cross section data integral yields were calculated and compared with experimental integral yield data reported in the literature. Potential use of proton induced reactions on Ba for production of (131)Cs is discussed.