Absolute emission intensities of the gamma rays from the decay of 224Ra and 212Pb progenies and the half-life of the 212 Pb decay.

Absolute gamma-ray emission intensities for 36 characteristic gamma rays from the decay of 224Ra, 212Pb, and their progeny were determined by measuring sources calibrated for activity by means of primary methods based on well-defined high-purity germanium (HPGe) detectors at both NIST and NPL. Results from the two laboratories agree with recent data evaluations, except for gamma rays with low emission intensities. The decay schemes have been re-balanced based on the new results. In addition, the half-life for 212Pb was measured using several HPGe detectors, ionization chambers, and a well-type NaI(Tl) detector.

Determination of the half-life and the absolute photon emission intensities for the main gamma-ray energies of 124I.

The National Institute of Standards and Technology (NIST) performed new standardization measurements for 124I. As part of this work the absolute photon emission intensity for the main gamma-rays of 124I were determined using several high-purity germanium (HPGe) detectors. In addition, the half-life for 124I was also determined using an HPGe detector. Ionization chamber measurements were performed for additional sources, but it was not possible to obtain a precise half-life value.

Determination of the internal pair production branching ratio of 90Y.

The National Institute of Standards and Technology (NIST) measured the internal pair production branching ratio of 90Y using two sources and four high purity germanium (HPGe) detectors to detect the resulting annihilation radiation. The internal pair production branching ratio determined from these measurements, (32.0 ±â€¯1.5) × 10-6 (k = 1), agrees within 1 standard uncertainty with the recommended value of (32.6 ±â€¯0.7) × 10-6 (k = 1) from the DDEP database.

Standardization of I-124 by three liquid scintillation-based methods.

A solution of 124I was standardized for activity by 4πß(LS)-γ(NaI) live-timed anticoincidence (LTAC) counting, with confirmatory measurements by triple-to-double coincidence ratio (TDCR) and CIEMAT-NIST efficiency tracing (CNET) liquid scintillation counting. The LTAC-based standard was shown to be in agreement (within k = 1 uncertainties) with previous measurements at NIST and elsewhere. Calibration settings for radionuclide calibrators were determined and a discrepancy with literature values, partially due to a calibration methodology dependent upon an erroneous setting for 18F, was identified and explained.

Standardization of 64Cu activity.

The complex decay scheme that makes 64Cu promising as both an imaging and therapeutic agent in medicine also makes the absolute measurement of its activity challenging. The National Institute of Standards and Technology (NIST) has completed a primary activity standardization of a 64CuCl2 solution using the 4πß(LS)-γ(NaI) live-timed anticoincidence (LTAC) counting method with a combined standard uncertainty of 0.51 %. Two liquid scintillation (LS) counting methods were employed for confirmatory measurements. Secondary measurements were made by high-purity germanium detectors, pressurized ionization chambers (IC), and a well-type NaI(Tl) counter. Agreement between the LTAC-based standard and standards from other laboratories was established via IC calibration factors. Poor agreement between methods and with theoretical IC responses may indicate a need for improved ß+/- branching probabilities and a better treatment of ß+/- spectra.

Southeast Asia's import demand for skim milk powder: Implications for US exporters.

Dairy industries in Southeast Asia are small and produce less than the domestic market demands. As expenditure and population grow in Southeast Asia, it is expected that the expenditures on skim milk powder (SMP) will grow. In this study, we examined the competitiveness of US SMP in the Southeast Asian market with respect to other leading dairy exporters, including the European Union (EU-28), New Zealand, and Australia. Using monthly data from 2006 to 2015, Rotterdam models were used to estimate import demands for SMP in 4 Southeast Asian countries. In a scenario using annual averages from 2013 to 2015 as a baseline, our findings suggest that a 10% reduction in the US price of SMP would cause Indonesia, Singapore, Vietnam, and the Philippines SMP imports from the United States to increase by 3.96, 0.44, 2.68, and 1.94 kt, respectively. Under the same scenario, the value of US SMP imports would decrease for Indonesia, Vietnam, and the Philippines by $4.12, $2.93, and $2.48 million, respectively; however, the value of US SMP to Singapore would increase by $0.20 million. Singapore and Indonesia expenditures for the US SMP are elastic, which means that as expenditure and population in Southeast Asia continue to grow, a 1% increase in SMP expenditure in Singapore and Indonesia would result in 1.25 and 1.20% increases in US SMP exports.

Results of an international comparison of activity measurements of 68Ge.

An international key comparison, identifier CCRI(II)-K2.Ge-68, has been performed. The National Institute of Standards and Technology (NIST) served as the pilot laboratory, distributing aliquots of a 68Ge/68Ga solution. Results for the activity concentration, CA, of 68Ge at a reference date of 12h00 UTC 14 November 2014 were submitted by 17 laboratories, encompassing many variants of coincidence methods and liquid-scintillation counting methods. The first use of 4π(Cherenkov)ß-γ coincidence and anticoincidence methods in an international comparison is reported. One participant reported results by secondary methods only. Two results, both utilizing pure liquid-scintillation methods, were identified as outliers. Evaluation using the Power-Moderated Mean method results in a proposed Comparison Reference Value (CRV) of 621.7(11)kBqg-1, based on 14 results. The degrees of equivalence and their associated uncertainties are evaluated for each participant. Several participants submitted 3.6mL ampoules to the BIPM to link the comparison to the International Reference System (SIR) which may lead to the evaluation of a Key Comparison Reference Value and associated degrees of equivalence.

Determination of photon emission probability for the main gamma ray and half-life measurements of 64Cu.

The National Institute of Standards and Technology (NIST) performed new standardization measurements for 64Cu. As part of this work the photon emission probability for the main gamma-ray line and the half-life were determined using several high-purity germanium (HPGe) detectors. Half-life determinations were also carried out with a NaI(Tl) well counter and two pressurized ionization chambers.

Activity measurements of the radionuclides 18F and 64Cu for the NIST, USA in the ongoing comparisons BIPM.RI(II)-K4.F-18 and BIPM.RI(II)-K4.Cu-64.

In 2016, comparisons of activity measurements of 18F and 64Cu using the Transfer Instrument of the International Reference System (SIRTI) took place at the National Institute of Standards and Technology (NIST, USA). This is the first SIRTI comparison for 64Cu. Ampoules containing about 27 kBq of 18F and 100 kBq of 64Cu solutions were measured in the SIRTI for about 5 and 1.5 half-lives, respectively. The NIST standardized the activity in the ampoules by ionization chamber measurements traceable to 4π(LS)ß-γ anticoincidence measurements. The comparisons, identifiers BIPM.RI(II)-K4.F-18 and BIPM.RI(II)-K4.Cu-64, are linked to the corresponding BIPM.RI(II)-K1.F-18 and BIPM.RI(II)-K1.Cu-64 comparisons and degrees of equivalence with the respective key comparison reference values have been evaluated. The NIST replaces its earlier degree of equivalence for 18F obtained in the frame of the CCRI(II)-K3.F-18 comparison in 2001.

Long-term stability of carrier-added (68)Ge standardized solutions.

Tests for chemical stability were carried out on carrier-added (68)Ge solutions prepared and calibrated in 2007 and 2011 to evaluate the suitability of the specific composition as a potential Standard Reference Material. Massic count rates of the stored solutions were measured using a NaI(Tl) well counter before and after gravimetric transfers. The present activity concentration of the 2007 solution was also measured using live-timed anticoincidence counting (LTAC) and compared to the 2007 calibrated value. The well counter data indicated no change in massic count rate to within uncertainties for either solution. The LTAC measurements gave a difference of -0.49% in the activity concentration 2007 solution over 7 years. However, the uncertainty in the decay correction over that time, due to the uncertainty in the (68)Ge half-life, accounted for the majority (0.67% out of 0.83%) of the standard uncertainty on the activity concentration. The results indicate that these carrier-added solutions are stable with regard to potential activity losses over several half-lives of (68)Ge.

Determination of photon emission probabilities for the main gamma-rays of ²²³Ra in equilibrium with its progeny.

The currently published (223)Ra gamma-ray emission probabilities display a wide variation in the values depending on the source of the data. The National Institute of Standards and Technology performed activity measurements on a (223)Ra solution that was used to prepare several sources that were used to determine the photon emission probabilities for the main gamma-rays of (223)Ra in equilibrium with its progeny. Several high purity germanium (HPGe) detectors were used to perform the gamma-ray spectrometry measurements.

Revision of the NIST Standard for (223)Ra: New Measurements and Review of 2008 Data.

After discovering a discrepancy in the transfer standard currently being disseminated by the National Institute of Standards and Technology (NIST), we have performed a new primary standardization of the alpha-emitter (223)Ra using Live-timed Anticoincidence Counting (LTAC) and the Triple-to-Double Coincidence Ratio Method (TDCR). Additional confirmatory measurements were made with the CIEMAT-NIST efficiency tracing method (CNET) of liquid scintillation counting, integral γ-ray counting using a NaI(Tl) well counter, and several High Purity Germanium (HPGe) detectors in an attempt to understand the origin of the discrepancy and to provide a correction. The results indicate that a -9.5 % difference exists between activity values obtained using the former transfer standard relative to the new primary standardization. During one of the experiments, a 2 % difference in activity was observed between dilutions of the (223)Ra master solution prepared using the composition used in the original standardization and those prepared using 1 mol·L(-1) HCl. This effect appeared to be dependent on the number of dilutions or the total dilution factor to the master solution, but the magnitude was not reproducible. A new calibration factor ("K-value") has been determined for the NIST Secondary Standard Ionization Chamber (IC "A"), thereby correcting the discrepancy between the primary and secondary standards.

A new NIST primary standardization of 18F.

A new primary standardization of (18)F by NIST is reported. The standard is based on live-timed beta-gamma anticoincidence counting with confirmatory measurements by three other methods: (i) liquid scintillation (LS) counting using CIEMAT/NIST (3)H efficiency tracing; (ii) triple-to-double coincidence ratio (TDCR) counting; and (iii) NaI integral counting and HPGe γ-ray spectrometry. The results are reported as calibration factors for NIST-maintained ionization chambers (including some "dose calibrators"). The LS-based methods reveal evidence for cocktail instability for one LS cocktail. Using an ionization chamber to link this work with previous NIST results, the new value differs from the previous reports by about 4%, but appears to be in good agreement with the key comparison reference value (KCRV) of 2005.

Patient education in allogeneic hematopoietic cell transplant: what patients wish they had known about quality of life.

Quality of life (QOL) is increasingly recognized as an important clinical outcome of hematopoietic cell transplantation (HCT), but patient education is often overlooked. The aim of the current qualitative study was to examine education regarding post-HCT QOL from the patient's perspective. Allogeneic HCT recipients participated in one of four focus groups. Participants were asked to recall what they had been told about post-HCT QOL as they were preparing for transplant, how their QOL differed from what they expected and how to educate future patients about post-HCT QOL. Verbatim transcripts were coded for both a priori and emergent themes using content analysis. A total of 24 patients participated (54% female, mean age 51, range 23-73 years). Participants frequently expressed the desire for additional education regarding post-HCT QOL, particularly late complications. They noted that late complications were often unexpected, had a profound impact on their QOL and threatened their ongoing sense of recovery. They emphasized that the timing, content and format of education regarding QOL should be flexible to meet their diverse needs. Findings from the current study draw attention to the importance of patient education regarding post-HCT QOL as well as additional QOL research designed with patient education in mind.

Development of a calibration methodology for large-volume, solid 68Ge phantoms for traceable measurements in positron emission tomography.

We have developed a methodology to calibrate the (68)Ge activity concentration in large (9L) cylindrical epoxy phantoms in a way that is traceable to national standards. The method was tested on two prototype cylindrical phantoms that are being used in a clinical trial and gave (68)Ge activity concentration values with combined standard uncertainties of about 1.1%. Imaging data from the phantoms using a calibrated PET-CT scanner gave values consistent with the calibrated activity concentrations within experimental uncertainties.

A systematic review and meta-analysis of changes in cognitive functioning in adults undergoing hematopoietic cell transplantation.

Evidence is mixed regarding the effects of hematopoietic cell transplantation (HCT) on changes in cognitive functioning among adults. Meta-analysis, which is designed to help reconcile conflicting findings, has not yet been conducted on studies of adults receiving HCT. To fill this gap, the current study provides a systematic review and meta-analysis of cognitive functioning in adults receiving HCT. A search of PubMed, PsycInfo, CINAHL, and Cochrane Library yielded 732 abstracts, which were independently evaluated by pairs of raters. Seventeen studies were systematically reviewed; 11 were retained for meta-analysis. There was agreement that cognitive impairments are evident for a subset of patients before HCT. Meta-analytical findings of 404 patients revealed no significant changes in cognitive functioning pre- to post HCT (P-values >0.05). Age, time since transplant and TBI were not associated with changes in cognitive functioning. Patients who received autologous transplants were more likely to demonstrate improvements in attention (P=0.004). The systematic review identified several limitations of existing literature, including small, clinically heterogeneous samples. Large, cooperative group studies are needed to address these design limitations. Nevertheless, results from the current meta-analysis suggest that cognitive functioning does not significantly change following HCT.

Calibration of Traceable Solid Mock (131)I Phantoms Used in an International SPECT Image Quantification Comparison.

The International Atomic Energy Agency (IAEA) has organized an international comparison to assess Single Photon Emission Computed Tomography (SPECT) image quantification capabilities in 12 countries. Iodine-131 was chosen as the radionuclide for the comparison because of its wide use around the world, but for logistical reasons solid (133)Ba sources were used as a long-lived surrogate for (131)I. For this study, we designed a set of solid cylindrical sources so that each site could have a set of phantoms (having nominal volumes of 2 mL, 4 mL, 6 mL, and 23 mL) with traceable activity calibrations so that the results could be properly compared. We also developed a technique using two different detection methods for individually calibrating the sources for (133)Ba activity based on a National standard. This methodology allows for the activity calibration of each (133)Ba source with a standard uncertainty on the activity of 1.4 % for the high-level 2-, 4-, and 6-mL sources and 1.7 % for the lower-level 23 mL cylinders. This level of uncertainty allows for these sources to be used for the intended comparison exercise, as well as in other SPECT image quantification studies.

Results of an international comparison for the activity measurement of 177Lu.

An international Key Comparison of (177)Lu has recently been carried out. Twelve laboratories performed assays for radioactivity content on aliquots of a common master solution of (177)Lu, leading to eleven results submitted for entry into the Key Comparison Database of the Mutual Recognition Arrangement. A proposed Comparison Reference Value (CRV) was calculated to be 3.288(4)MBq/g using all eleven results. Degrees of equivalence and their uncertainties were calculated for each laboratory based on the CRV. Most of the values reported by the participating laboratories were within 0.6% of the CRV.

Standardization of radium-223 by liquid scintillation counting.

Liquid scintillation (LS) counting was undertaken as part of the primary standardization of (223)Ra. Radium-223 decays with a half life of 11.43 d through a chain of shorter-lived daughter radionuclides, resulting in five alpha decays and three beta decays. The CIEMAT/NIST method of tritium efficiency tracing was employed, with the beta efficiencies being calculated using the program CN2004, developed by the Physikalisch-Technische Bundesanstalt (PTB). The total calculated LS efficiency, considering all daughter radionuclides, was approximately 598%. Separate experiments were performed to rule out loss of the 3.96 s (219)Ra daughter from the cocktail and possible counting loss of the 1.78 ms (215)Po daughter due to LS counter dead-time. No loss was observed in either experiment. In the final experiment an expanded uncertainty (k=2) of 0.55% was achieved. Results were in excellent agreement with confirmatory measurements performed by 2pialpha proportional counting. However, results are not in agreement with methods based on gamma ray measurements.