ICRP Publication 133: The ICRP computational framework for internal dose assessment for reference adults: specific absorbed fractions

Dose coefficients for assessment of internal exposures to radionuclides are radiological protection quantities giving either the organ equivalent dose or effective dose per intake of radionuclide following ingestion or inhalation. In the International Commission on Radiological Protection’s (ICRP) Occupational Intakes of Radionuclides (OIR) publication series, new biokinetic models for distribution of internalised radionuclides in the human body are presented as needed for establishing time-integrated activity within organs of deposition (source regions). This series of publications replaces Publications 30 and 68 (ICRP, 1979, 1980, 1981, 1988, 1994b). In addition, other fundamental data needed for computation of the dose coefficients are radionuclide decay data (energies and yields of emitted radiations), which are given in Publication 107 (ICRP, 2008), and specific absorbed fraction (SAF) values – defined as the fraction of the particle energy emitted in a source tissue region that is deposited in a target tissue region per mass of target tissue. This publication provides the technical basis for SAFs relevant to internalised radionuclide activity in the organs of Reference Adult Male and Reference Adult Female as defined in Publications 89 and 110 (ICRP, 2002, 2009). SAFs are given for uniform distributions of mono-energetic photons, electrons, alpha particles, and fission-spectrum neutrons over a range of relevant energies. Electron SAFs include both collision and radiative components of energy deposition. SAF data are matched to source and target organs of the biokinetic models of the OIR publication series, as well as the Publication 100 (ICRP, 2006) Human Alimentary Tract Model and the Publication 66 (ICRP, 1994a) Human Respiratory Tract Model, the latter as revised within Publication 130 (ICRP, 2015). This publication further outlines the computational methodology and nomenclature for assessment of internal dose in a manner consistent with that used for nuclear medicine applications. Numerical data for particle-specific and energy-dependent SAFs are given in electronic format for numerical coupling to the respiratory tract, alimentary tract, and systemic biokinetic models of the OIR publication series.

Superconducting Coplanar Waveguide Filters for Submillimeter Wave On-Chip Filterbank Spectrometers

We show the first experimental results which prove that superconducting NbTiN coplanar-waveguide resonators can achieve a loaded Q factor in excess of 800 in the 350 GHz band. These resonators can be used as narrow band pass filters for on-chip filter bank spectrometers for astronomy. Moreover, the low-loss coplanar waveguide technology provides an interesting alternative to microstrip lines for constructing large scale submillimeter wave electronics in general.

Cryogenically-cooled Yb:YGAG ceramic mode-locked laser

This work reports on a liquid-nitrogen-cooled, SESAM mode-locked Yb:YGAG (Yb:Y(3)Ga(2)Al(3)O(12)) ceramic laser. The Yb:YGAG has a similar structure to Yb:YAG, but its emission spectrum at low temperature remains much broader, which is suitable for ultrashort pulse generation and amplification. A stable pulse train with 119-MHz repetition rate was obtained at a wavelength of 1026 nm. The measured pulse duration is 2.4 ps, which is more than four times shorter than that achieved with a cryogenically-cooled Yb:YAG. Furthermore, laser performance of the Yb:YGAG ceramics in continuous-wave operation and wavelength tunability at 80 K was investigated.

CO2 adsorption–desorption performance of mesoporous zirconium hydroxide with robust water durability

The present study demonstrates for the first time, the development of mesoporous zirconium hydroxide with high CO₂ capacity and sustainable adsorption–desorption performance within a broad range of pressures (100–3000 kPa).

Elevated receptor for activated C kinase 1 expression is involved in intracellular Ca2+ influx and potentially associated with compromised regulatory T cell function in patients with asthma

BACKGROUND

Regulatory T cells (T(regs)) are activated during anergy in response to T cell receptor (TCR) activation and functional immune suppression. Anergy of paediatric T(regs) is partially dependent on intracellular calcium mobility; following TCR activation, T(regs) do not exhibit increased intracellular Ca(2+) concentration ([Ca(2+) ](i)).

OBJECTIVE

We determined whether [Ca(2+) ](i) in adult T(regs) defined their anergy, if intracellular Ca(2+) movement was linked to regulatory functions, whether [Ca(2+)](i) was indicative of asthma pathology, and the potential molecular mechanism responsible for Ca(2+) movement in T(regs).

METHODS

T(regs) were purified by the magnetic bead method, and their regulatory functions were assessed by monitoring carboxyfluorescein succinimidyl ester-labelled responder T cell proliferation. The Ca(2+) response of Fura-2-labelled cells was measured using a video image analysis system. To analyse the functions of T(regs) at the molecular level, we generated Jurkat Tet-On(®) clones with doxycycline (Dox)-induced forkhead box P3 (FOXP3) protein expression.

RESULTS

CD4(+) CD25(+) CD127(-/low) T(regs) from participants without asthma did not elicit Ca(2+) influx in response to TCR activation, exhibited little proliferation and suppressed proliferation of CD4(+) CD25(-) T cells. In contrast, under similar conditions, T(regs) from patients with asthma exhibited increased [Ca(2+)](i) and robust proliferation with partial loss of regulatory functions. FOXP3 protein levels in Tet-On(®) clones were high after both 2- and 5-day Dox treatment; however, 5-day cells were comparable with T(regs) from patients with asthma, whereas 2-day cells were similar to T(regs) from participants without asthma. Increasing [Ca(2+)](i) induced a high level of receptor for activated C kinase 1 (RACK1) expression in 5-day cells.

CONCLUSIONS AND CLINICAL RELEVANCE

We confirmed that T(regs) in patients with asthma are functionally impaired and that the abnormal regulatory functions of these cells can be analysed by [Ca(2+)](i) following TCR engagement. Furthermore, the impaired functioning of T(regs) evident in patients with asthma may be due to a high level of RACK1.

Two γ-ray bursts from dusty regions with little molecular gas

Long-duration γ-ray bursts are associated with the explosions of massive stars and are accordingly expected to reside in star-forming regions with molecular gas (the fuel for star formation). Previous searches for carbon monoxide (CO), a tracer of molecular gas, in burst host galaxies did not detect any emission. Molecules have been detected as absorption in the spectra of γ-ray burst afterglows, and the molecular gas is similar to the translucent or diffuse molecular clouds of the Milky Way. Absorption lines probe the interstellar medium only along the line of sight, so it is not clear whether the molecular gas represents the general properties of the regions where the bursts occur. Here we report spatially resolved observations of CO line emission and millimetre-wavelength continuum emission in two galaxies hosting γ-ray bursts. The bursts happened in regions rich in dust, but not particularly rich in molecular gas. The ratio of molecular gas to dust (<9-14) is significantly lower than in star-forming regions of the Milky Way and nearby star-forming galaxies, suggesting that much of the dense gas where stars form has been dissipated by other massive stars.

The pharmacokinetics and safety profiles of belimumab after single subcutaneous and intravenous doses in healthy Japanese volunteers

WHAT IS KNOWN AND OBJECTIVES

Belimumab is a recombinant human monoclonal antibody that binds and antagonizes the biological activity of soluble B-lymphocyte stimulator (BLyS) protein. BLyS appears to play a role in the pathogenesis of systemic lupus erythematosus, and the biological profile of belimumab suggests that it may have a therapeutic benefit in the treatment for the disease. In this healthy Japanese subjects study, we investigated the pharmacokinetics and safety of a single subcutaneous and intravenous injection of belimumab administered as a 200 mg/mL liquid formulation.

METHODS

This was an open-label, randomized, parallel-group, single-dose study in healthy Japanese subjects. Each subject received a single intravenous infusion or a subcutaneous injection of 200 mg belimumab. The pharmacokinetic parameters and safety parameters including local tolerance (injection site), biomarkers, immunogenicity and adverse events were evaluated up to 70 days post-dosing.

RESULTS

After a single intravenous or a subcutaneous administration of 200 mg belimumab, all 16 subjects completed the study. There were no serious adverse events or adverse events related to injection site reactions. All seven adverse events were considered mild or moderate in intensity and deemed unrelated to belimumab except for cellulitis following intravenous administration. The bioavailability of the single subcutaneous dose of 200 mg belimumab in the subjects was estimated to be 77·5%. Time to the maximum serum concentration after subcutaneous injection was 6·5 days (median). The geometric mean terminal half-life was comparable between the two administration routes (17·7 days intravenous and 15·9 days subcutaneous). Serum immunoglobulin G level decreased slightly after each treatment. No subjects were found to produce antibelimumab antibodies.

WHAT IS NEW AND CONCLUSIONS

A favourable absolute bioavailability in healthy Japanese subjects was seen following a subcutaneous injection of 200 mg belimumab. Considering the intersubject variability, exposures were consistent with those previously observed in healthy non-Japanese subjects. Safety and biomarker data were also consistent with previous non-Japanese clinical studies.

The effect of growth media and physical treatments on the adhesion properties of canine probiotics

AIMS

The manufacturing processes have been reported to influence the properties of probiotics with potential impact on health properties. The aim was to investigate the effect of different growth media and inactivation methods on the properties of canine-originated probiotic bacteria alone and in combination mixture.

METHODS AND RESULTS

Three established dog probiotics, Lactobacillus fermentum VET9A, Lactobacillus plantarum VET14A and Lactobacillus rhamnosus VET16A, and their combination mixture were evaluated for their adhesion to dog mucus. The effect of different growth media, one reflecting laboratory and the other manufacturing conditions, and inactivation methods (95°C, 80°C and UV irradiation) on the mucus adhesion of the probiotic strains was characterized. Evaluation of dog probiotics was supported by cell visualization using transmission electron microscopy (TEM). Higher adhesion percentage was reported for probiotic strains growing in laboratory rather than in manufacturing conditions (P < 0.05). Inactivation by heat (95°C, 80°C) decreased the adhesion properties when strains were cultivated in soy-based growth media compared with those grown in MRS broth (P < 0.05). TEM observations uncovered differences in cell-surface components in nonviable forms of probiotic strains as compared with their viable forms.

CONCLUSIONS

Manufacturing process conditions such as growth media and pretreatment methods may significantly affect the adhesive ability of the tested strains.

SIGNIFICANCE AND IMPACT OF THE STUDY

Growth conditions, growth media, pretreatment methods and different probiotic combinations should be carefully considered for quality control of existing probiotics and for identification of new probiotics for dogs. These may also have an impact on health benefits for the host.

Dose indices in dental cone beam CT and correlation with dose-area product

OBJECTIVES

In the 2011 project "Safety and efficacy of a new and emerging dental X-ray modality (SEDENTEXCT)", it was suggested that dose index (DI) and dose-area product (DAP) could be easily measured and used as diagnostic reference levels (DRLs), which would help in the management of radiation doses to patients in optimum exposure settings. Such indices could be directly related to effective dose. The purposes of this study, therefore, were to measure and calculate the DI and DAP in cone beam CT (CBCT) machines and to evaluate the correlation between the two.

METHODS

Dose measurements were performed on three-dimensional cone beam CT (3D-CBCT) machines [3D Accuitomo (J. Morita Mfg. Corp., Kyoto, Japan), Veraviewepocs (J. Morita Mfg. Corp.) and CS9300 (Carestream, New York, NY)] by exposing a cylindrical poly-methyl methacrylate (PMMA) phantom using a CT ionization chamber. These dose measurements were used for the calculation of Dose Indices 1 and 2, according to the methodology suggested by SEDENTEXCT. The DAP was measured using a DAP meter that was attached to the detector to cover the entire irradiated area.

RESULTS

The DI1 ranged from 53.6 mR to 216.6 mR, the DI2 ranged from 77.1 mR to 325.0 mR and the DAP ranged from 101.1 mGy cm(2) to 457.9 mGy cm(2), depending on the machines and exposure settings. Index 2 had a better correlation with the DAP than Index 1.

CONCLUSIONS

The DIs and DAP proposed by SEDENTEXCT may be useful for establishing DRLs for dental CBCT machines; however, further studies are necessary to determine which of these indices provide accurate dose estimates proportionally relating to the effective dose.

A preliminary study to determine the diagnostic reference level using dose-area product for limited-area cone beam CT

OBJECTIVES

The aim of this study was to measure the dose-area product (DAP) of limited-area cone beam CT (CBCT) units used by dental offices, and to evaluate the rationale of the DAP with an aid of optically stimulated luminescence (OSL) dosemeter in measuring radiation dose.

METHOD

The DAPs of 21 CBCT units used in the dental offices of Tokyo and the surrounding areas from five different manufacturers were measured using OSL nanoDot dosemeter. An assembly of OSL dosemeters with an X-ray film was exposed by CBCT units at exposure parameters commonly used in each dental office. DAP values were then calculated as expressed in mGy cm(2).

RESULTS

DAP values ranged from 126.7 mGy cm(2) to 1476.9 mGy cm(2), depending on the units used.

CONCLUSION

OSL dosemeter coupled with film can be utilized for a large-scale study to measure DAP. The DAP values for individual CBCT units depend not only on the field of view, but also on the exposure parameters adapted by the dental offices.

Image quality assessment of three cone beam CT machines using the SEDENTEXCT CT phantom

OBJECTIVES

The SEDENTEXCT Project proposed quality assurance (QA) methods and introduced a QA image quality phantom. A new prototype was recently introduced that may be improved according to previous reports. The purpose of this study is to evaluate image quality in various protocols of three cone beam CT (CBCT) machines using the proposed QA phantom.

METHODS

Using three CBCT machines, nine image quality parameters, including image homogeneity (noise), uniformity, geometrical distortion, pixel intensity value, contrast resolution, spatial resolution [line pair (LP) chart, point spread function (PSF) and modulation transfer function (MTF)] and metal artefacts, were evaluated using a QA phantom proposed by SEDENTEXCT. Exposure parameters, slice thickness and field of view position changed variously, and the number of total protocols was 22.

RESULTS

Many protocols showed a uniform gray value distribution except in the minimum slice thickness image acquired using 3D Accuitomo 80 (Morita, Kyoto, Japan) and Veraviewepocs 3Df (Morita). Noise levels differed among the protocols. There was no geometric distortion, and the pixel intensity values were correlated with the CT value. Low contrast resolution differed among the protocols, but high contrast resolution performed well in all. Many protocols showed that the maximum line pair was larger than 1 LP mm(-1) but smaller than 3 LP mm(-1). PSF and MTF did not correlate well with the pixel size. The measured metal artefact areas varied for each device.

CONCLUSIONS

We studied the image quality of three CBCT machines using the SEDENTEXCT phantom. Image quality varied with exposure protocols and machines.

Ruthenium(II) complexes containing quinone based ligands: synthesis, characterization, catalytic applications and DNA interaction

1,2-Naphthaquinone reacts with amines such as semicarbazide, isonicotinylhydrazide and thiosemicarbazide in high yield procedure with the formation of tridentate ligands HL(n) (n=1-3). By reaction of ruthenium(II) starting complexes and quinone based ligands HL(n) (n=1-3), a series of ruthenium complexes were synthesized and characterized by elemental and spectroscopic methods (FT-IR, electronic, (1)H, (13)C, (31)P NMR and ESI-MS). The ligands were coordinated to ruthenium through quinone oxygen, imine nitrogen and enolate oxygen/thiolato sulfur. On the basis of spectral studies an octahedral geometry may be assigned for all the complexes. Further, the catalytic oxidation of primary, secondary alcohol and transfer hydrogenation of ketone was carried out. The DNA cleavage efficiency of new complexes has also been tested.

Radiation transport calculations for cosmic radiation

The radiation environment inside and near spacecraft consists of various components of primary radiation in space and secondary radiation produced by the interaction of the primary radiation with the walls and equipment of the spacecraft. Radiation fields inside astronauts are different from those outside them, because of the body's self-shielding as well as the nuclear fragmentation reactions occurring in the human body. Several computer codes have been developed to simulate the physical processes of the coupled transport of protons, high-charge and high-energy nuclei, and the secondary radiation produced in atomic and nuclear collision processes in matter. These computer codes have been used in various space radiation protection applications: shielding design for spacecraft and planetary habitats, simulation of instrument and detector responses, analysis of absorbed doses and quality factors in organs and tissues, and study of biological effects. This paper focuses on the methods and computer codes used for radiation transport calculations on cosmic radiation, and their application to the analysis of radiation fields inside spacecraft, evaluation of organ doses in the human body, and calculation of dose conversion coefficients using the reference phantoms defined in ICRP Publication 110.

Organ doses from environmental exposures calculated using voxel phantoms of adults and children

This paper presents effective and organ dose conversion coefficients for members of the public due to environmental external exposures, calculated using the ICRP adult male and female reference computational phantoms as well as voxel phantoms of a baby, two children and four adult individual phantoms--one male and three female, one of them pregnant. Dose conversion coefficients are given for source geometries representing environmental radiation exposures, i.e. whole body irradiations from a volume source in air, representing a radioactive cloud, a plane source in the ground at a depth of 0.5 g cm⁻², representing ground contamination by radioactive fall-out, and uniformly distributed natural sources in the ground. The organ dose conversion coefficients were calculated employing the Monte Carlo code EGSnrc simulating the photon transport in the voxel phantoms, and are given as effective and equivalent doses normalized to air kerma free-in-air at height 1 m above the ground in Sv Gy(-1). The findings showed that, in general, the smaller the body mass of the phantom, the higher the dose. The difference in effective dose between an adult and an infant is 80-90% at 50 keV and less than 40% above 100 keV. Furthermore, dose equivalent rates for photon exposures of several radionuclides for the above environmental exposures were calculated with the most recent nuclear decay data. Data are shown for effective dose, thyroid, colon and red bone marrow. The results are expected to facilitate regulation of exposure to radiation, relating activities of radionuclides distributed in air and ground to dose of the public due to external radiation as well as the investigation of the radiological effects of major radiation accidents such as the recent one in Fukushima and the decision making of several committees.

Characterization of optically stimulated luminescence dosemeters to measure organ doses in diagnostic radiology

OBJECTIVE

The aim of this study was to assess the characteristics of an optically stimulated luminescence dosemeter (OSLD) for use in diagnostic radiology and to apply the OSLD in measuring the organ doses by panoramic radiography.

METHODS

The dose linearity, energy dependency and angular dependency of aluminium oxide-based OSLDs were examined using an X-ray generator to simulate various exposure settings in diagnostic radiology. The organ doses were then measured by inserting the dosemeters into an anthropomorphic phantom while using three panoramic machines.

RESULTS

The dosemeters demonstrated consistent dose linearity (coefficient of variation<1.5%) and no significant energy dependency (coefficient of variation<1.5%) under the applied exposure conditions. They also exhibited negligible angular dependency (≤ 10%). The organ doses of the X-ray as a result of panoramic imaging by three machines were calculated using the dosemeters.

CONCLUSION

OSLDs can be utilized to measure the organ doses in diagnostic radiology. The availability of these dosemeters in strip form proves to be reliably advantageous.

Reliability of a multiplex PCR assay for the identification of the major Campylobacter taxa

The primer pair (C412F/C1228R) constructed previously for the polymerase chain reaction (PCR) identification of the genus Campylobacter using an approximate 800 base pair (bp) 16S rRNA gene target segment proved to be useful for the identification of a total of 49 Campylobacter lari isolates including urease-positive thermophilic Campylobacter (UPTC) organisms (n=25). When the primer pair (CLF/R) developed previously for the PCR identification of C. lari species using an approximate 250 bp glyA segment was employed, 27 C. lari isolates, including all the UPTC isolates, were identified to be PCR-negative (55%). Therefore, this PCR procedure developed for the molecular identification of C. lari was shown to be unreliable for C. lari identification. Nucleotide sequencing analysis clarified the reason(s) why PCR-negative examples occurred in many C. lari isolates, including UPTC isolates. The primer pair target sequences in the C. lari-specific PCR-negative isolates apparently varied at the 3' end region, as compared with C. lari-specific PCR-positive isolates. Thus, the multiplex PCR assay developed previously was shown to be unreliable for the molecular identification of C. lari subspecies organisms.

Development of a web-based CT dose calculator: WAZA-ARI

A web-based computed tomography (CT) dose calculation system (WAZA-ARI) is being developed based on the modern techniques for the radiation transport simulation and for software implementation. Dose coefficients were calculated in a voxel-type Japanese adult male phantom (JM phantom), using the Particle and Heavy Ion Transport code System. In the Monte Carlo simulation, the phantom was irradiated with a 5-mm-thick, fan-shaped photon beam rotating in a plane normal to the body axis. The dose coefficients were integrated into the system, which runs as Java servlets within Apache Tomcat. Output of WAZA-ARI for GE LightSpeed 16 was compared with the dose values calculated similarly using MIRD and ICRP Adult Male phantoms. There are some differences due to the phantom configuration, demonstrating the significance of the dose calculation with appropriate phantoms. While the dose coefficients are currently available only for limited CT scanner models and scanning options, WAZA-ARI will be a useful tool in clinical practice when development is finalised.