Evaluation of excitation functions of 100Mo(p,d+pn)99Mo and 100Mo (p,2n)99mTc reactions: Estimation of long-lived Tc-impurity and its implication on the specific activity of cyclotron-produced (99m)Tc.

Excitation functions were calculated by the code TALYS for 10 proton-induced reactions on (100)Mo. For (100)Mo(p,d+pn)(99)Mo and (100)Mo(p,2n)(99m)Tc, calculations were also performed using the code STAPRE. Furthermore, for those two reactions and (nat)Mo(p,x)(96)Tc, evaluation of available experimental data was also carried out. The production of (99m)Tc via the (100)Mo(p,2n)-process is discussed. The ratio of atoms of long-lived (99g)Tc and (98)Tc to those of (99m)Tc is appreciably higher in cyclotron production than in generator production of (99m)Tc; this may adversely affect the preparation of (99m)Tc-chelates.

Evaluation of excitation functions of proton, ³He- and α-particle induced reactions for production of the medically interesting positron-emitter bromine-76.

Cross section data for production of the medically interesting radionuclide 76Br (T(½)=16.2 h) via the proton induced reactions on 76Se, 77Se, 78Se and 79Br, and ³He- and α-particle induced reactions on 75As were evaluated. The nuclear model codes STAPRE, EMPIRE and TALYS were used to check the consistency in the experimental data and a statistical procedure was applied to derive the recommended excitation functions. A comparison of various production routes of 76Br (and of 75Br) is presented.

Excitation functions of α-particle induced reactions on enriched 123Sb and (nat)Sb for production of 124I.

Excitation functions of (α,xn) reactions on 98.28% enriched (123)Sb and on (nat)Sb were measured from 9 to 40 MeV. The data could be described well in terms of statistical and precompound models using the code TALYS. The discrepancies in the literature data for the formation of (125)I and (126)I were solved. The nuclear reaction (123)Sb(α,3n)(124)I on an enriched target appears to be interesting for the production of (124)I (T(1/2)=4.18 d) over the energy range E(α)=42→32 MeV, its yield being 11.7 MBq/µAh. The levels of the radionuclidic impurities (125)I and (126)I amount to 1.8% and 0.6%, respectively. The use of (nat)Sb as target material for (124)I production is unsuitable due to the high level of (123)I impurity.

Evaluation of excitation functions of 3He- and α-particle induced reactions on antimony isotopes with special relevance to the production of iodine-124.

Cross section data were evaluated for the production of the medically important positron emitter (124)I (T(1/2)=4.18d) via (3)He- and α-particle induced reactions on Sb isotopes. The consistency in the measured data available in the literature was checked against the cross section calculations of three nuclear model codes (i.e. STAPRE, EMPIRE and TALYS). The recommended excitation functions obtained by a statistical procedure were used to derive the integral yields. An assessment of the (124)I yields and associated radioisotopic impurities suggests that the (123)Sb(α,3n)(124)I process over the energy range of E(α)=45 → 32 MeV could be of potential interest for the production of (124)I.

Radiochemical determination of cross sections of alpha-particle induced reactions on 192Os for the production of the therapeutic radionuclide 193mPt.

For determination of cross sections of alpha-particle induced reactions on 99.65% enriched (192)Os, the methods for electrolytic preparation of thin samples and radiochemical separation of radioplatinum were optimized. The excitation functions of the (192)Os(alpha,n)(195m)Pt and (192)Os(alpha,3n) (193m)Pt reactions were measured from 20 to 39 MeV. The cross section of the latter reaction reaches a maximum value of about 1.5b at an energy around 36 MeV. The results of nuclear model calculations using the codes TALYS and STAPRE agreed well with the measured data. The optimum energy range for the production of no-carrier-added (193m)Pt (T(1/2)=4.33 d) was found to be E(alpha)=40-->30 MeV. The thick target yield amounts to 10 MBq/microA h and a possible batch yield of 2 GBq should be sufficient for Auger electron therapy on a wide scale.

An Am/Be neutron source and its use in integral tests of differential neutron reaction cross-section data.

An Am/Be neutron source, installed recently at the Rajshahi University, is described. Neutron flux mapping was done using the nuclear reactions (197)Au(n,gamma)(198)Au, (113)In(n,gamma)(114m)In, (115)In(n,n'gamma)(115m)In and (58)Ni(n,p)(58)Co. An approximate validation of the neutron spectral shape was done using five neutron threshold detectors and the iterative unfolding code SULSA. Integral cross sections of the reactions (54)Fe(n,p)(54)Mn, (59)Co(n,p)(59)Fe and (92)Mo(n,p)(92m)Nb were measured with fast neutrons (E(n)>1.5MeV) and compared with data calculated using the neutron spectral distribution and the excitation function of each reaction given in data libraries: an agreement within +/-6% was found.

Evaluation of excitation functions of proton and deuteron induced reactions on enriched tellurium isotopes with special relevance to the production of iodine-124.

Cross-section data for the production of medically important radionuclide (124)I via five proton and deuteron induced reactions on enriched tellurium isotopes were evaluated. The nuclear model codes, STAPRE, EMPIRE and TALYS, were used for consistency checks of the experimental data. Recommended excitation functions were derived using a well-defined statistical procedure. Therefrom integral yields were calculated. The various production routes of (124)I were compared. Presently the (124)Te(p,n)(124)I reaction is the method of choice; however, the (125)Te(p,2n)(124)I reaction also appears to have great potential.

Intercomparison of methods for coincidence summing corrections in gamma-ray spectrometry.

A comparison of the coincidence summing correction methods is presented. Since there are several ways for computing these corrections, each method has advantages and drawbacks that could be compared. This part of the comparison was restricted to point sources. The same experimental spectra, decay scheme and photon emission intensities were used by all the participants. The results were expressed as coincidence summing correction factors for several energies of (152)Eu and (134)Cs, and three source-to-detector distances. They are presented and discussed.

A comprehensive evaluation of charged-particle data for production of the therapeutic radionuclide (103)Pd.

(103)Pd is an important radionuclide having a half-life of 16.99d, which is suitable for internal radiation therapy, especially used for the treatment of prostate cancer. Its production in no-carrier-added form is done via charged-particle-induced reactions and the data are available in EXFOR library. We evaluated six charged-particle-induced reactions, namely (nat)Ag(p,x)(103)Pd, (103)Rh(p,n)(103)Pd, (103)Rh(d,2n)(103)Pd, (100)Ru(alpha,n)(103)Pd, (101)Ru(alpha,2n)(103)Pd, and (102)Ru((3)He,2n)(103)Pd process. In the first case, analysis was done up to about 100MeV but in other cases only up to about 25 or 40MeV. Furthermore, an evaluation of the data for the (nat)Ag(p,x)(103)Ag process was also done since it may serve as a typical example for the (103)Ag-->(103)Pd precursor system. A statistical procedure supported by nuclear model calculations using the codes STAPRE, EMPIRE 2.19, and TALYS was used to validate and fit the experimental data. The recommended sets of data derived together with confidence limits are reported. The application of those data, particularly in the calculation of integral yields, is discussed. A comparison of the investigated routes from the viewpoint of practical applicability to the production of (103)Pd is given. Presently the (103)Rh(p,n)(103)Pd reaction is the method of choice.

Excitation function of the 192Os(3He,4n)-reaction for production of 191Pt.

In search of an alternative production route of the therapeutically and environmentally interesting radionuclide (191)Pt (T(1/2)=2.8 d), excitation function of the (192)Os((3)He,4n)(191)Pt reaction was measured from its threshold up to 36 MeV. Thin samples of enriched (192)Os were prepared by electrodeposition on Ni-foils, and the conventional stacked-foil technique was used for cross-section measurements. The experimental data were compared with the results of theoretical calculations using the codes ALICE-IPPE and TALYS. Good agreement was found with TALYS. The theoretical thick target yield of (191)Pt over the energy range E(3He)=36-->25 MeV amounts to 6.7 MBq/microA h. A comparison of various investigated production methods of (191)Pt is given. The here investigated (192)Os((3)He,4n)-process leads to very high-purity (191)Pt (>99.5%).

Nuclear data for production of the therapeutic radionuclides 32P, 64Cu, 67Cu, 89Sr, 90Y and 153Sm via the (n,p) reaction: evaluation of excitation function and its validation via integral cross-section measurement using a 14 MeV d(Be) neutron source.

Nuclear data for production of the therapeutic radionuclides 32P, 64Cu, 67Cu, 89Sr, 90Y and 153Sm via (n,p) reactions on the target nuclei 32S, 64Zn, 67Zn, 89Y, (90)Zr and 153Eu, respectively, are discussed. The available information on each excitation function was analysed. From the recommended data set for each reaction the average integrated cross section for a standard 14 MeV d(Be) neutron field was deduced. The spectrum-averaged cross section was also measured experimentally. A comparison of the integrated value with the integral measurement served to validate the excitation function within about 15%. A fast neutron source appears to be much more effective than a fission reactor for production of the above-mentioned radionuclides in a no-carrier-added form via the (n,p) process. In particular, the possibility of production of high specific activity 153Sm is discussed.

Experimental study and nuclear model calculations on the 192Os(p,n)192Ir reaction: Comparison of reactor and cyclotron production of the therapeutic radionuclide 192Ir.

In a search for an alternative route of production of the important therapeutic radionuclide (192)Ir (T(1/2)=78.83 d), the excitation function of the reaction (192)Os(p,n)(192)Ir was investigated from its threshold up to 20 MeV. Thin samples of enriched (192)Os were obtained by electrodeposition on Ni, and the conventional stacked-foil technique was used for cross section measurements. The experimental data were compared with the results of theoretical calculations using the codes EMPIRE-II and ALICE-IPPE. Good agreement was found with EMPIRE-II, but slightly less with the ALICE-IPPE calculations. The theoretical thick target yield of (192)Ir over the energy range E(p)=16-->8 MeV amounts to only 0.16MBq/muA.h. A comparison of the reactor and cyclotron production methods is given. In terms of yield and radionuclidic purity of (192)Ir the reactor method appears to be superior; the only advantage of the cyclotron method could be the higher specific activity of the product.

Measurements and nuclear model calculations on proton-induced reactions on 103Rh up to 40 MeV: evaluation of the excitation function of the 103Rh(p,n)103Pd reaction relevant to the production of the therapeutic radionuclide 103Pd.

Excitation functions were measured by the stacked-foil technique for the reactions 103Rh(p,n)103Pd, 103Rh(p,3n)101Pd and 103Rh(p,4n)100Pd from their respective thresholds up to 39.6 MeV. The radioactivity of the activation products was determined by high-resolution X-ray and gamma-ray spectrometry. Statistical model calculations taking into account the precompound effects were performed for all reactions, and good agreement was found with our data. A critical evaluation of the existing and present data for the 103Rh(p,n)103Pd reaction was carried out. Recommended cross sections and integral yields for this reaction of key importance in the production of the widely used therapeutic radionuclide 103Pd are given.

Cross sections of (n,p), (n,alpha) and (n,2n) reactions on some isotopes of zirconium in the neutron energy range of 10-12 MeV and integral tests of differential cross section data using a 14 MeV d(Be) neutron spectrum.

Cross sections were measured for the 90Zr(n,alpha)87mSr, 90Zr(n,2n)89m,gZr, 91Zr(n,p)91mY, 92Zr(n,p)92Y, 94Zr(n,alpha)91Sr and 96Zr(n,2n)95Zr reactions over the neutron energy range of 11.4 to 12.4 MeV and for the 94Zr(n,p)94Y reaction from 9.2 to 12.4 MeV. Nuclear model calculations were performed up to 16MeV. The statistical model incorporating precompound effects reproduces excitation functions of the three major threshold reactions, namely (n,p), (n,alpha) and (n,2n), quite well. Spectrum averaged cross sections were measured using a thick target Be(d,n) neutron field at Ed = 14 MeV. For the same neutron field averaged reaction cross sections were deduced using the excitation functions measured in this work as well as those given in the ENDF/B-VI, JEF-2, JENDL-3.2, BROND and ADL-3 data files. A comparison of the experimental and deduced integral data helped validating the differential data.

Nuclear model calculations on proton and deuteron induced reactions on 122Te and 120Te with particular reference to the formation of the isomeric states 120m,gI.

Nuclear model calculations were performed on (p,xn) reactions on 122Te and 120Te, and (d,xn) reactions on 120Te. The computer code used (STAPRE) incorporates statistical and precompound models as well as nuclear structure effects. The total cross-sections of (p,xn) and (d,xn) processes leading to the formation of the radioisotopes 119I, 120gI, 121I and 122I are described well by the calculations. The isomeric cross-section, however, is rather difficult to calculate. The yield of the high spin isomer (120mI) depends on the type of reaction involved and increases with the increasing projectile energy. From an analysis of the energy dependence of the isomeric cross-section ratio, the excitation energy of 120mI was deduced to be 550+/-50 keV and its spin and parity as 4+. The experimental data reported earlier and the theoretical analysis presented in this work allow to define the optimum conditions for the production of the medically important beta+ emitter 120gI with enhanced confidence.