3D printing of realistic body phantoms: Comparison of measured and simulated organ doses on the example of a CT scan on a pregnant woman.

Background: Medical examinations or treatment of pregnant women using ionizing radiation are sometimes unavoidable. In such cases, the risk of harm to the embryo and fetus after exposure to ionizing radiation must be carefully estimated. However, no commercially available anthropomorphic body phantoms of pregnant women are available for dose measurements.

Joint EURADOS-EANM initiative for an advanced computational framework for the assessment of external dose rates from nuclear medicine patients.

Background: In order to ensure adequate radiation protection of critical groups such as staff, caregivers and the general public coming into proximity of nuclear medicine (NM) patients, it is necessary to consider the impact of the radiation emitted by the patients during their stay at the hospital or after leaving the hospital. Current risk assessments are based on ambient dose rate measurements in a single position at a specified distance from the patient and carried out at several time points after administration of the radiopharmaceutical to estimate the whole-body retention. The limitations of such an approach are addressed in this study by developing and validating a more advanced computational dosimetry approach using Monte Carlo (MC) simulations in combination with flexible and realistic computational phantoms and time activity distribution curves from reference biokinetic models.

Effects of ionising radiation exposure in offspring and next generations: dosimetric aspects and uncertainties.

Purpose: The impact of the exposure to ionizing radiation in the offspring and next generation has been investigated in the last decades and currently is the subject of study of the ICRP Task Group 121. Studying the effects of radiation exposure in pre-conceptional and post-conceptional phases can be a challenge since potential effects to the fetus vary depending on the stage of fetal development. Epidemiology and radiobiology studies are the two sources of information one can use to correlate the radiation dose to the human body and tissues and the resulting effects.

Modelling DTPA therapy following Am contamination in rats.

A major challenge in modelling the decorporation of actinides (An), such as americium (Am), with DTPA (diethylenetriaminepentaacetic acid) is the fact that standard biokinetic models become inadequate for assessing radionuclide intake and estimating the resulting dose, as DTPA perturbs the regular biokinetics of the radionuclide. At present, most attempts existing in the literature are empirical and developed mainly for the interpretation of one or a limited number of specific incorporation cases. Recently, several approaches have been presented with the aim of developing a generic model, one of which reported the unperturbed biokinetics of plutonium (Pu), the chelation process and the behaviour of the chelated compound An-DTPA with a single model structure.

Reproduction of a conventional anthropomorphic female chest phantom by 3D-printing: Comparison of image contrasts and absorbed doses in CT.

Background: The production of individualized anthropomorphic phantoms via three-dimensional (3D) printing methods offers promising possibilities to assess and optimize radiation exposures for specifically relevant patient groups (i.e., overweighed or pregnant persons) that are not adequately represented by standardized anthropomorphic phantoms.

Dose-efficiency quantification of computed tomography systems using a model-observer.

Background: Recent advances in computed tomography (CT) technology have considerably improved the quality of CT images and reduced radiation exposure in patients. At present, however, there is no generally accepted figure of merit (FOM) for comparing the dose efficiencies of CT systems.

Purpose: (i) To establish an FOM that characterizes the quality of CT images in relation to the radiation dose by means of a mathematical model observer and (ii) to evaluate the new FOM on different CT systems and image reconstruction algorithms.

Pediatric computed tomography doses in Germany from 2016 to 2018 based on large-scale data collection.

Purpose: Accumulating evidence from epidemiological studies that pediatric computed tomography (CT) examinations can be associated with a small but non-zero excess risk for developing leukemia or brain tumor highlights the need to optimize doses of pediatric CT procedures. Mandatory dose reference levels (DRL) can support reduction of collective dose from CT imaging. Regular surveys of applied dose-related parameters are instrumental to decide when technological advances and optimized protocol design allow lower doses without sacrificing image quality.

A revised compartmental model for biokinetics and dosimetry of 2-[F]FDG.

Background: The aim was to review available biokinetic data, collect own experimental data, and propose an updated compartmental model for 2-[F]FDG in the frame of the revision of the ICRP report on dose coefficients for radiopharmaceuticals used in diagnostic nuclear medicine.

Methods: The compartmental model was developed based on published biokinetic data for 2-[F]FDG. Additional data on urinary excretion in 23 patients (11 males, 12 females) undergoing whole-body PET/CT examinations were obtained within this study.

Tissue equivalence of 3D printing materials with respect to attenuation and absorption of X-rays used for diagnostic and interventional imaging.

Introduction: Three-dimensional printing is a promising technology to produce phantoms for quality assurance and dosimetry in X-ray imaging. Crucial to this, however, is the use of tissue equivalent printing materials. It was thus the aim of this study to evaluate the properties of a larger number of commercially available printing filaments with respect to their attenuation and absorption of X-rays.

Dose Variations Using an X-Ray Cabinet to Establish Dose-Response Curves for Biological Dosimetry Assays.

In biological dosimetry, dose-response curves are essential for reliable retrospective dose estimation of individual exposure in case of a radiation accident. Therefore, blood samples are irradiated and evaluated based on the applied assay. Accurate physical dosimetry of the irradiation performance is a critical part of the experimental procedure and is influenced by the experimental setup, especially when X-ray cabinets are used.

Radiation field and dose inhomogeneities using an X-ray cabinet in radiation biology research.

Purpose: X-ray cabinets are replacing Cs/ Co sources in radiation biology research due to advantages in size, handling, and radiation protection. However, because of their different physical properties, X-ray cabinets are more susceptible to experimental influences than conventional sources. The aim of this study was to examine the variations related to the experimental setups typically used to investigate biological radiation effects with X-ray cabinets.

International intercomparison on internal dose assessment (ICIDOSE 2017).

Internal dose assessment intercomparison exercises are useful tools: to verify the performance of an internal dosimetry service; to promote the harmonisation of dose assessments; and to identify weaknesses where further improvements are necessary. However, no such international intercomparisons have been performed for more than ten years. In the period May 2014-May 2016, the 'Technical Recommendations for Monitoring Individuals for Occupational Intakes of Radionuclides' were developed on the initiative of the European Commission, and later published within the EC Radiation Protection series, as RP188.

Method to quickly and accurately calculate absorbed dose from therapeutic and stray photon exposures throughout the entire body in individual patients.

Purpose: Photon radiotherapy techniques typically devote considerable attention to limiting the exposure of healthy tissues outside of the target volume. Numerous studies have shown, however, that commercial treatment planning systems (TPSs) significantly underestimate the absorbed dose outside of the treatment field. The purpose of this study was to test the feasibility of quickly and accurately calculating the total absorbed dose to the whole body from photon radiotherapy in individual patients.

THE EURADOS WORK TOWARDS A REVIEW ON RETROSPECTIVE DOSIMETRY AFTER INCORPORATION OF RADIONUCLIDES.

Biological dosimetry methods are well established and validated for providing dose estimates following external radiation exposures. In contrast, interpreting biological dosimetry data in cases of internal exposures is still challenging. In this context, a joint collaboration between two Working Groups (WG) of European Radiation Dosimetry Group (EURADOS), WG10 on 'Retrospective Dosimetry' and WG7 on 'Internal Dosimetry', was initiated with the aim to address the main issues related to the advantages and limitations of biological and electron paramagnetic resonance (EPR) dosimetry in cases of internal and mixed internal/external exposures.

A puzzling case of contamination with Am.

Two people were exposed to and contaminated with Am. In vivo determinations of the incorporated Am were performed using a whole-body counter and two partial-body counters for the skull and lung, respectively. Additionally, urine samples were analysed to estimate the systemic activity removed from the body.

Current knowledge on radon risk: implications for practical radiation protection? radon workshop, 1/2 December 2015, Bonn, BMUB (Bundesministerium für Umwelt, Naturschutz, Bau und Reaktorsicherheit; Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety).

ICRP suggested a strategy based on the distinction between a protection approach for dwellings and one for workplaces in the previous recommendations on radon. Now, the Commission recommends an integrated approach for the protection against radon exposure in all buildings irrespective of their purpose and the status of their occupants. The strategy of protection in buildings, implemented through a national action plan, is based on the application of the optimisation principle below a derived reference level in concentration (maximum 300 Bq m(-3)).

Concerted Uranium Research in Europe (CURE): toward a collaborative project integrating dosimetry, epidemiology and radiobiology to study the effects of occupational uranium exposure.

The potential health impacts of chronic exposures to uranium, as they occur in occupational settings, are not well characterized. Most epidemiological studies have been limited by small sample sizes, and a lack of harmonization of methods used to quantify radiation doses resulting from uranium exposure. Experimental studies have shown that uranium has biological effects, but their implications for human health are not clear.

Models and phantoms for internal dose assessment.

Radiation doses delivered by incorporated radionuclides cannot be directly measured, and they are assessed by means of biokinetic and dosimetric models and computational phantoms. For emitters of short-range radiation like alpha-particles or Auger electrons, the doses at organ levels, as they are usually defined in internal dosimetry, are no longer relevant. Modelling the inter- and intra-cellular radiation transport and the local patterns of deposition at molecular or cellular levels are the challenging tasks of micro- and nano-dosimetry.

A recycling model of the biokinetics of systemic tellurium.

Purpose: To develop a compartmental model of the systemic biokinetics of tellurium required for calculating the internal dose and interpreting bioassay measurements after incorporation of radioactive tellurium.

Materials And Methods: The compartmental model for tellurium was developed with the software SAAM II v. 2.

Developing a physiologically based approach for modeling plutonium decorporation therapy with DTPA.

Purpose: To develop a physiologically based compartmental approach for modeling plutonium decorporation therapy with the chelating agent Diethylenetriaminepentaacetic acid (Ca-DTPA/Zn-DTPA).

Materials And Methods: Model calculations were performed using the software package SAAM II (©The Epsilon Group, Charlottesville, Virginia, USA). The Luciani/Polig compartmental model with age-dependent description of the bone recycling processes was used for the biokinetics of plutonium.

Considerations on the ICRP model predictions of the transfer of (137)Cs from food to the milk and urine of lactating mothers.

A recent work has shown that the current ICRP biokinetic model for the transfer of caesium radionuclides from food to human breast milk was able to describe with satisfactory accuracy (137)Cs activity concentrations in human breast samples collected a few weeks after the Chernobyl accident as well as in samples collected some years later. However, systematic discrepancies were observed for the predictions of the activity concentrations in urine samples. In the present work, modifications to the model were investigated with the aim of improving the agreement between model predictions and data.

A compartmental model for biokinetics and dosimetry of 18F-choline in prostate cancer patients.

Unlabelled: PET with (18)F-choline ((18)F-FCH) is used in the diagnosis of prostate cancer and its recurrences. In this work, biodistribution data from a recent study conducted at Skåne University Hospital Malmö were used for the development of a biokinetic and dosimetric model.

Methods: The biodistribution of (18)F-FCH was followed for 10 patients using PET up to 4 h after administration.

Validation of the ICRP model for caesium intake by lactating mothers with Italian data after the Chernobyl fallout.

In the aftermath of the Chernobyl nuclear power plant accident, a research group of the Italian National Institute of Health (Istituto Superiore di Sanità) carried out two research programmes on maternal milk. One concerned the transfer of caesium radionuclides from the diet to breast milk. In the other, the activity concentrations of (137)Cs were also determined in urine and placenta.

Nonlinear compartmental model of 18F-choline.

Introduction: This work develops a compartmental model of (18)F-choline in order to evaluate its biokinetics and so to describe the temporal variation of the radiopharmaceuticals' uptake in and clearance from organs and tissues.

Methods: Ten patients were considered in this study. A commercially available tool for compartmental analysis (SAAM II) was used to model the values of activity concentrations in organs and tissues obtained from PET images or from measurements of collected blood and urine samples.

Daily urinary excretion of uranium in members of the public of Southwest Nigeria.

The main aim of this study was to determine and evaluate urinary excretion values of uranium in members of the public of Southwest Nigeria living in areas of low environmental uranium. As several uranium mines are running in Nigeria and the operations could be a risk of contamination for the workers as well as for the members of the public, biomonitoring of urine could provide information about the exposure to uranium for the subjects. Therefore, baseline values of uranium in urine are needed from subjects living in areas without mining activities.