Rhodium Target Research Articles

A Laboratory Setup for Express Electrochemical Dissolution of a Powder Rhodium Target

A Laboratory Setup for Express Electrochemical Dissolution of a Powder Rhodium Target

Separation of103Pd from a Rh target using an alloying pretreatment with bismuth

AbstractPalladium-103 is one of the most attractive radionuclides for internal radiotherapy. It is not only used as a brachytherapy seed but is also a feasible candidate for Auger electron therapy and gold-nanoparticle therapy. In this study, we propose a new method for the separation of103Pd from a rhodium target to obtain no-carrier-added103Pd. Rhodium powder target was irradiated under the following conditions: proton, 50 MeV, 1–3 μA, 1–4 h for the separation study; and H2+, 24 MeV, 5 μA, 1 h to produce103Pd. The irradiated target was pretreated using an alloying reaction between Rh and Bi on a hotplate at 500 °C. Rhodium in the chemical form of a Bi–Rh compound could then be dissolved with nitric acid and103Pd was extracted using dimethylglyoxime as an extractant. The target rhodium was recycled using sodium tetrahydroborate (NaBH4). We obtained103Pd with a yield of 87%. The activity of the product was 26 ± 2 MBq at the end of bombardment (EOB), and the radionuclidic purity of103Pd was greater than 99%. The decontamination factors of rhodium and bismuth in the103Pd product were estimated to be greater than 104and 105, respectively. The target rhodium was recycled with a yield of 91% with a trace of bismuth (9 μg/50 mg Rh). The total separation time for103Pd was within 3.5 h.

Synthesis, characterization and hydrogen sensing properties of nanosized colloidal rhodium oxides prepared by Pulsed Laser Ablation in water

Nanosized colloidal rhodium oxide particles in water were obtained by using a nanosecond pulsed excitation, starting from a high purity rhodium target. The as-synthesized colloids show an almost spherical shape and size in the range between 2 and 12 nm. Characterization results indicate that colloidal particles are composed mainly of oxidized RhxOy phases, whose content increase after annealing at 200 °C in air and decrease under hydrogen treatment in mild conditions, suggesting a reversible behavior. The hydrogen sensing characteristics of thin films deposited by drop casting from the colloidal solution onto alumina sensor substrates provided with platinum interdigitated electrodes, were also investigated. The developed conductometric hydrogen sensor shows high response to low concentration of the target gas in air at low operating temperature and full reversibility with fast dynamics. Further, a good selectivity towards hydrogen was demonstrated, testing other simple molecules such as CO, CO2, NO2 and O2. To our knowledge, this is the first report on the use of nanosized rhodium/rhodium oxide colloids in conductometric gas sensors.

Excitation function and yield for the 103Rh(d,2n)103Pd nuclear reaction: Optimization of the production of palladium-103

Deuteron-induced nuclear reactions for the generation of 103Pd were investigated using the stacked-foil activation technique on rhodium targets at deuteron energies up to Ed=33MeV. The excitation functions of the reactions 103Rh(d,xn)101,103Pd, 103Rh(d,x)100g,cum,101m,g,102m,gRh and 103Rh(d,2p)103Ru have been measured, and the Thick-Target Yield for 103Pd has been calculated.

Spinal pathomorphological changes in the breeding giant salamander juveniles

The Chinese giant salamander (Andrias davidianus, Blanchard, 1871) is the largest amphibian on earth. While the number of the wild Chinese giant salamanders is declining and becoming a rare endangered species, breeding of giant salamander in China has launched since 1980s. However, scoliosis often occurs in the breeding giant salamander juveniles. To explore the pathomorphological changes and bone mineral density of the morbid breeding giant salamander, molybdenum–rhodium target X-ray photography and conventional histopathological analysis have been adopted to investigate the disease occurred in affected salamander juveniles. Vertebra, spinal core, vertebral foramen, paravertebral skeletal muscle, and other related parts were examined. The results showed that the bone mineral density in the body-curved giant salamander juveniles is significant lower compared to the peer normal controls (p > 0.05). In addition, spinal cord, spine, and its surrounding muscles were deformed in the diseased salamander.

Digital breast tomosynthesis: observer performance of clustered microcalcification detection on breast phantom images acquired with an experimental system using variable scan angles, angular increments, and number of projection views.

To investigate the dependence of microcalcification cluster detectability on tomographic scan angle, angular increment, and number of projection views acquired at digital breast tomosynthesis ( DBT digital breast tomosynthesis ). A prototype DBT digital breast tomosynthesis system operated in step-and-shoot mode was used to image breast phantoms. Four 5-cm-thick phantoms embedded with 81 simulated microcalcification clusters of three speck sizes (subtle, medium, and obvious) were imaged by using a rhodium target and rhodium filter with 29 kV, 50 mAs, and seven acquisition protocols. Fixed angular increments were used in four protocols (denoted as scan angle, angular increment, and number of projection views, respectively: 16°, 1°, and 17; 24°, 3°, and nine; 30°, 3°, and 11; and 60°, 3°, and 21), and variable increments were used in three (40°, variable, and 13; 40°, variable, and 15; and 60°, variable, and 21). The reconstructed DBT digital breast tomosynthesis images were interpreted by six radiologists who located the microcalcification clusters and rated their conspicuity. The mean sensitivity for detection of subtle clusters ranged from 80% (22.5 of 28) to 96% (26.8 of 28) for the seven DBT digital breast tomosynthesis protocols; the highest sensitivity was achieved with the 16°, 1°, and 17 protocol (96%), but the difference was significant only for the 60°, 3°, and 21 protocol (80%, P < .002) and did not reach significance for the other five protocols (P = .01-.15). The mean sensitivity for detection of medium and obvious clusters ranged from 97% (28.2 of 29) to 100% (24 of 24), but the differences fell short of significance (P = .08 to >.99). The conspicuity of subtle and medium clusters with the 16°, 1°, and 17 protocol was rated higher than those with other protocols; the differences were significant for subtle clusters with the 24°, 3°, and nine protocol and for medium clusters with 24°, 3°, and nine; 30°, 3°, and 11; 60°, 3° and 21; and 60°, variable, and 21 protocols (P < .002). With imaging that did not include x-ray source motion or patient motion during acquisition of the projection views, narrow-angle DBT digital breast tomosynthesis provided higher sensitivity and conspicuity than wide-angle DBT digital breast tomosynthesis for subtle microcalcification clusters.

Estimation of mean glandular dose for contrast enhanced digital mammography: factors for use with the UK, European and IAEA breast dosimetry protocols

The UK, European and IAEA protocols for breast dosimetry in mammography use tabulations of conversion factors, which relate measurements of incident air kerma to the mean glandular dose to the breast. To supplement the existing tabulations, a Monte Carlo computer program has been used to calculate conversion factors for the high-energy spectra used for contrast enhanced digital mammography. The calculations were made for the x-ray spectra from a tungsten target (tube voltage range 40–50 kV) filtered by 0.28, 0.30 and 0.32 mm of copper, and from molybdenum and rhodium targets (tube voltage range 40–49 kV), each filtered by 0.30 mm of copper. The g-factors for all of these spectra were plotted for each breast thickness as a function of half value layer (HVL) and were found to lie on smooth curves within 0.3%. These reflect the fact that the characteristic x-rays present in the spectra from molybdenum and rhodium are heavily filtered and all the spectra are essentially Bremsstrahlung. As a consequence, the s-factor previously used in the dosimetry protocols to adjust for different target/filter combinations can be taken as unity for all of the spectra considered. Tables of g-factors and c-factors are provided for breast thicknesses in the range 20–110 mm and HVLs in the range 2.4–3.6 mm of aluminium. The tables of c-factors are given for breast glandularities in the range 0.1%–100% and for typical glandularities for women in the age bands 40–49 and 50–64 attending the UK national breast screening programme.

Isolation of palladium-103 from rhodium targets

Known and newly developed methods for dissolving Rh metal with the aim to transfer gram amounts of an irradiated rhodium target into solution are discussed and compared. Extraction of microamounts of Pd against the background of macroamounts of Rh with modified sulfur-containing crown ethers and quaternary ammonium salts is studied. Procedures are suggested for isolation of carrier-free 103Pd from rhodium targets irradiated at accelerators.

The role of d-orbital polarization on rhodium cluster collisions

The effects due to d-orbital polarization in collision processes between a single rhodium atom and a 12 atom rhodium cluster are investigated by means of ab initio molecular dynamics. For the initial configuration of the 12 atom rhodium targets we adopt two different low energy structures. The kinetic energy and impact parameter of the projectile are chosen in such a way that fusion, scattering and fragmentation of the cluster do occur. The collision is treated by means of density functional theory molecular dynamics (DFT-MD). Both spin unpolarized and polarized treatments are implemented in order to clearly distinguish the effects that are due to d-orbital polarization. We find a novel block dynamics, of parts of the cluster, which is due to the directional nature of d-bonds. In addition, the treatment of the collisions by means of high temperature DFT dynamics yields promising minimal energy configurations, which are target dependent but are difficult to obtain otherwise.

Investigation of palladium-103 production and IR07- 103Pd brachytherapy seed preparation

In this study, design and fabrication of 103Pd brachytherapy seed was investigated. The excitation functions of 103Rh(p,n) 103Pd and 103Rh(d,2n) 103Pd reactions were calculated using EMPIRE (version 3.1 Rivoli), ALICE/ASH and TALYS-1.2 codes, the TENDL-2010 database and compared with the published data. Production of 103Pd was done via 103Rh(p,n) 103Pd nuclear reaction. The target was bombarded with 18 MeV protons at 200 μA beam current for 15 h. After irradiation and radiochemical separation of the electroplated rhodium target, the optimum condition for absorption of 103Pd into Amberlite®IR-93 resin was achieved at 0.5 M HCl. Version 5 of the (MCNP) Monte Carlo radiation transport code was employed to calculate the dosimetric parameters around the 103Pd brachytherapy seed. Finally the calculated results were compared with published results for other commercial sources.

Impact ionisation spectra from hypervelocity impacts using aliphatic poly(methyl methacrylate) microparticle projectiles

We report impact ionisation spectra from spherical poly(methyl methacrylate) (PMMA) microparticles of 724 nm diameter impacting a rhodium target. These projectiles were coated with an ultrathin (~11 nm) overlayer of polypyrrole, an electrically conducting organic polymer; this enabled the accumulation of sufficient surface charge to allow electrostatic acceleration up to speeds of 4 to 8 km s(-1) using a high-voltage Van de Graaff instrument. A grid above the target (held at 3.33 kV cm(-1) with respect to the target) accelerated the cations that were generated during the hypervelocity impacts, and these ions then drifted to a charge detector. By measuring the collected charge vs. time and assuming only single ionisation events, time-of-flight mass spectra were obtained. Strong signals were observed for cationic species with ions of m/z 41, 65 and 115. There were also minor contributions from cations with masses ranging from m/z 29 to 142. The three major signals are assigned to fragment ions (C(3)H(5)(+), C(4)H(5)O(+)/C(5)H(9)(+) and C(6)H(11)O(2)(+)) which are known to be associated with the decomposition of PMMA. These impact ionisation spectra differ significantly from those reported earlier using polystyrene (PS) microparticles. The aliphatic PMMA microparticles generate small (m/z <100) fragment ions more readily at lower speeds than the predominantly aromatic PS microparticles, where speeds of at least 10 km s(-1) are typically required for substantial yields of low-mass fragment ions. This correlates well with the well-known greater chemical and thermal fragility of PMMA compared to PS. The PMMA microparticles should prove useful synthetic mimics for aliphatic carbonaceous micrometeorites.

Molybdenum Target in the digital enviromnent, to study the image characteristics of early breast cancer

Objective To improve the pairs of molybdenum and rhodium target X ray of early breast cancer diagnostic accuracy. Methods 41 cases confirmed by surgery and pathology of early breast cancer X ray findings were analyzed retrospectively. Results signs of early breast cancer: 23 cases of nodular masses;calcification in 17 cases, X ray no clear lumps or nodules and calcification of the only 2 cases of malignant signs; non-symmetry of high density 12; limitations associated with skin thickening nipple retraction in 2 cases.Conclusion ①mass is an important basis for the diagnosis of early breast cancer;②micro-calcification is still an important basis for the diagnosis of early breast cancer, even more than the direct signs of (mass) more specific; ③non-symmetry of the limitations of dense breast structure of local distortions disorders, inflammation and surgical history of the exclusion, it should be possible to consider breast cancer ;④In addition to malignant calcification, the more than two kinds of indirect signs of co-exist, we should attach great importance to be further examination or short-term review. Key words: Early breast cancer; Rh-Mo double-target Photography Diagnosis

Discriminating contamination from particle components in spectra of Cassini's dust detector CDA

The Chemical Analyser subsystem of the Cosmic Dust Analyser (CDA) aboard the Cassini spacecraft performs in situ measurements of the chemical composition of dust in space. The instrument records time-of-flight mass spectra of cations, extracted from the impact cloud that is created by high-velocity particle impacts onto the detector target. Thus, the spectra not only show signals of particle components but also of ions from the target material and target contamination. The aim of this work is to determine which non-particle ions are to be expected in the spectra obtained in space operation at Saturn. We present an analysis of the contamination state of the instrument's impact target. Beside investigations of the purity of the rhodium target surface, spectra from CDA calibration experiments at the dust accelerator facility are evaluated with regard to contamination signatures. Furthermore, contamination mass lines in spectra obtained by impacts of Jovian and Saturnian dust stream particles are analysed. Due to their small size and high speed, stream particle impacts predominantly produce ions from the target material and therefore the spectra are excellent probes of the contamination state of the target operating in space. With the exception of adsorbed hydrogen and carbon, the level of contamination is very low. Implications for CDA spectra of Saturnian E ring particle impacts are derived. The findings confirm the published interpretations. The low level of alkali metal contamination implies a significant sodium contribution in the composition of E ring ice particles. Additionally, ionisation thresholds for the occurrence of contamination mass lines can be utilised to set limits for the impact velocity.

Glandular radiation dose in tomosynthesis of the breast using tungsten targets

With the advent of new detector technology, digital tomosynthesis imaging of the breast has, in the past few years, become a technique intensely investigated as a replacement for planar mammography. As with all other x‐ray–based imaging methods, radiation dose is of utmost concern in the development of this new imaging technology. For virtually all development and optimization studies, knowledge of the radiation dose involved in an imaging protocol is necessary. A previous study characterized the normalized glandular dose in tomosynthesis imaging and its variation with various breast and imaging system parameters. This characterization was performed with x‐ray spectra generated by molybdenum and rhodium targets. In the recent past, many preliminary patient studies of tomosynthesis imaging have been reported in which the x‐ray spectra were generated with x‐ray tubes with tungsten targets. The differences in x‐ray distribution among spectra from these target materials make the computation of new normalized glandular dose values for tungsten target spectra necessary. In this study we used previously obtained monochromatic normalized glandular dose results to obtain spectral results for twelve different tungsten target x‐ray spectra. For each imaging condition, two separate values were computed: the normalized glandular dose for the zero degree projection angle (DgN0), and the ratio of the glandular dose for non‐zero projection angles to the glandular dose for the zero degree projection (the relative glandular dose, RGD(α)). It was found that DgN0 is higher for tungsten target x‐ray spectra when compared with DgN0 values for molybdenum and rhodium target spectra of both equivalent tube voltage and first half value layer. Therefore, the DgN0 for the twelve tungsten target x‐ray spectra and different breast compositions and compressed breast thicknesses simulated are reported. The RGD(α) values for the tungsten spectra vary with the parameters studied in a similar manner to that found for the molybdenum and rhodium target spectra. The surface fit equations and the fit coefficients for RGD(α) included in the previous study were also found to be appropriate for the tungsten spectra.PACS numbers: 87.57.uq

Extraction separation of no-carrier-added 103Pd from irradiated Rh target, Cu and Zn using α-furyldioxime, dimethylglyoxime and α-benzildioxime

Solvent extraction of no-carrier-added 103Pd from irradiated rhodium target hydrochloric solution was investigated using α-furyldioxime, dimethylglyoxime and α-benzildioxime as extracts in chloroform. The best extractant yield for a single run was 96.9% with dimethylglyoxime from 0.93 M HCl and 103Pd purity was better than 99.99%.

40kV용 투과 양극형 x-ray tube의 개발 및 특성분석

휴대용 XRF (X-Ray Fluorescence) 장치에 적용할 수 있는 40 kV용 투과 양극형 W-Target tube와 Rh-Target tube를 개발하고 특성을 조사하였다. 특성 x-ray의 에너지와 연속 x-ray의 선량특성은 알려진 결과와 잘 일치함을 확인하였고, 최대 선량을 추출하기 위한 양극금속 박막의 최적 두께는 W-target tube의 경우 약 <TEX>$2.6{\mu}m$</TEX>, Rh-target tube의 경우 약 <TEX>$2.7{\mu}m$</TEX> 임을 밝혀내었다. 또한 관전압 40 kV, 관전류 <TEX>$60{\mu}A$</TEX>로 30분 동안 연속적으로 작동시켰을 때 양극에서의 온도는 <TEX>$50^{\circ}C$</TEX>를 넘지 않아 휴대용 XRF장치에 적용할 수 있음을 확인하였다. Tungsten and rhodium target tube for a 40 kV x-ray transmission anode was developed to apply to the hand-held XRF(X-Ray Fluorescence) apparatus and its characteristics were evaluated. From the measurement of the energy distribution and dose of x-ray, it was confirmed that our results were good agreements with the known ones. The optimum thickness of metal film deposited on Be window to extract the maximum dose were <TEX>$2.6{\mu}m$</TEX> and <TEX>$2.7{\mu}m$</TEX> in case of W-target tube and Rh-target tube, respectively. When it was continuously worked during 30 min. at 40 kV in tube voltage and at <TEX>$60{\mu}A$</TEX> in tube current, the temperature at target did not exceed <TEX>$50^{\circ}C$</TEX>. Our results reveals that the 40 kV x-ray transmission anode tube can be applied to the hand-held XRF apparatus.

Initial Clinical Experience With Contrast-Enhanced Digital Breast Tomosynthesis

Contrast-enhanced digital mammography and digital breast tomosynthesis are two imaging techniques that attempt to increase malignant breast lesion conspicuity. The combination of these into a single technique, contrast-enhanced digital breast tomosynthesis (CE-DBT), could potentially integrate the strengths of both. The objectives of this study were to assess the clinical feasibility of CE-DBT as an adjunct to digital mammography, and to correlate lesion enhancement characteristics and morphology obtained with CE-DBT to digital mammography, ultrasound, and magnetic resonance (MR). CE-DBT (GE Senographe 2000D; Milwaukee, WI) was performed as a pilot study in an ongoing National Cancer Institute-funded grant (P01-CA85484) studying multimodality breast imaging. Thirteen patients with ACR BI-RADS category 4 or 5 breast lesions underwent imaging with digital mammography, ultrasound, MR, and CE-DBT. CE-DBT was performed at 49 kVp with a rhodium target and a 0.27-mm copper (Alfa Aesar, Ward Hill, MA) filter. Preinjection and postinjection DBT image sets were acquired in the medial lateral oblique projection with slight compression. Each image set consists of nine images acquired over a 50-degree arc and was obtained with a mean glandular x-ray dose comparable to two conventional mammographic views. Between the precontrast and postcontrast DBT image sets, a single bolus of iodinated contrast agent (1 ml/kg at 2 ml/s, Omnipaque-300; Amersham Health Inc., Princeton, NJ) was administered. Images were reconstructed using filtered-backprojection in 1-mm increments and transmitted to a clinical PACS workstation. Initial experience suggests that CE-DBT provides morphologic and vascular characteristics of breast lesions qualitatively concordant with that of digital mammography and MR. As an adjunct to digital mammography, CE-DBT may be a potential alternative tool for breast lesion morphologic and vascular characterization.

Solvent extraction of no-carrier-added 103Pd from irradiated rhodium target with a-furyldioxime

Solvent extraction of no-carrier-added 103Pd was investigated from irradiated rhodium target with a-furyldioxime in chloroform from diluted hydrochloric acid. Extraction yield was 85.3% for a single extraction from 0.37M HCl and 103Pd purity was better than 99%.

Development of [103Pd]-2-acetylpyridine 4N-methyl thiosemicarbazone complex for targeted therapy

Due to interesting biological properties of palladium-thiosemicarbazono complexes, production of a 103Pd-labeled anti-cancer complex, i.e., [103Pd]-2-acetylpyridine 4N-methylthiosemicarbazone ([103Pd]-APMTS) was developed. Palladium-103 (T1/2 = 16.96 d) produced via the 103Rh(p,n)103Pd nuclear reaction using natural rhodium target, was separated from the irradiated target material. Proton energy was 18 MeV with 200 mA irradiation for 15 hours (final activity 700 mCi of 103Pd2+, RCY>95%, radionuclidic purity>99%). The final activity was eluted in form of Pd(NH3)2Cl2 in order to react with 2-acetylpyridine-4N-methylthiosemicarbazone to yield [103Pd]-APMTS. Chemical purity of the final product was confirmed to be within the accepted limits by polarography. [103Pd]-APMTS was prepared with a radiochemical yield of more than 80% at room temperature after 3 hours. The labeling reaction was optimized for time, temperature and radioactivity and ligand ratio. A mixture of APMTS and Pd activity in ethanol was heated at 90 °C for 3 hours followed by reverse phase SPE purification using C18 plus Sep-Pak. Radiochemical purity of more than 99% using RTLC and specific activity of about 12500 Ci/mol was obtained. The stability of the tracer was checked in the final product and the presence of human serum at 37 °C up to 3 hours. The partition coefficient of the final complex was determined by octanol : saline buffer distribution.

Electroplating/electrodissolution/recovery cycle for rhodium target used for an industrial scale cyclotron production of palladium-l03

Summary Electrodeposition of rhodium metal on a copper backing was performed in acidic sulfate media using RhCl3 · 3 H2O, Rh2(SO4)3 (recovered from hydrochloric acid solution) and also the commercially available Rhodex plating baths. This work describes the development of a high current density (2.4 A·cm-2) electrodissolution system that allows solubilisation of rhodium fragments, powder and pieces of foils and wires in the presence of hydrochloric and chlorine gas. Solvent-solvent extraction of no-carrier-added 103Pd from the irradiated rhodium target with a-furyldioxime into chloroform under the influence of hydrochloric acid concentration was investigated. The extraction yield was 85.3% for a single extraction with 0.37 M HCl, and 103Pd was more than 99% pure.