Accounting for radiation exposure from previous CT exams while deciding on the next exam: What do referring clinicians think?

Purpose: To obtain clinicians' views of the need to account for radiation exposure from previous CT scans and the advisability of a regulatory mechanism to control the number of CT scans for an individual patient.

Methods: A convenience survey was conducted by emailing a link to a three-question electronic survey to clinicians in many countries, mostly through radiology and radiation protection contacts.

Results: 505 responses were received from 24 countries.

Radiation Safety and Accidental Radiation Exposures in Nuclear Medicine.

Medical radiation accidents and unintended events may lead to accidental or unintended medical exposure of patients and exposure of staff or the public. Most unintended exposures in nuclear medicine will lead to a small increase in risk; nevertheless, these require investigation and a clinical and dosimetric assessment. Nuclear medicine staff are exposed to radiation emitted directly by radiopharmaceuticals and by patients after administration of radiopharmaceuticals.

Quantitative implications of the updated EARL 2019 PET-CT performance standards.

Purpose: Recently, updated EARL specifications (EARL2) have been developed and announced. This study aims at investigating the impact of the EARL2 specifications on the quantitative reads of clinical PET-CT studies and testing a method to enable the use of the EARL2 standards whilst still generating quantitative reads compliant with current EARL standards (EARL1).

Methods: Thirteen non-small cell lung cancer (NSCLC) and seventeen lymphoma PET-CT studies were used to derive four image datasets-the first dataset complying with EARL1 specifications and the second reconstructed using parameters as described in EARL2.

Multicentre quantitative Ga PET/CT performance harmonisation.

Purpose: Performance standards for quantitative F-FDG PET/CT studies are provided by the EANM Research Ltd. (EARL) to enable comparability of quantitative PET in multicentre studies. Yet, such specifications are not available for Ga.

Updating PET/CT performance standards and PET/CT interpretation criteria should go hand in hand.

This letter aims at explaining that adjusting the performance of PET/CT systems to a new standard also requires updating of interpretation criteria. Simply changing one aspect of the imaging procedure, i.e.

Feasibility of PET/CT system performance harmonisation for quantitative multicentre Zr studies.

Purpose: The aim of this study was to investigate the variability in quantitative performance and feasibility of quantitative harmonisation in Zr PET/CT imaging.

Methods: Eight EANM EARL-accredited (Kaalep A et al., Eur J Nucl Med Mol Imaging 45:412-22, 2018) PET/CT systems were investigated using phantom acquisitions of uniform and NEMA NU2-2007 body phantoms.

Feasibility of state of the art PET/CT systems performance harmonisation.

Purpose: The objective of this study was to explore the feasibility of harmonising performance for PET/CT systems equipped with time-of-flight (ToF) and resolution modelling/point spread function (PSF) technologies. A second aim was producing a working prototype of new harmonising criteria with higher contrast recoveries than current EARL standards using various SUV metrics.

Methods: Four PET/CT systems with both ToF and PSF capabilities from three major vendors were used to acquire and reconstruct images of the NEMA NU2-2007 body phantom filled conforming EANM EARL guidelines.

EANM/EARL FDG-PET/CT accreditation - summary results from the first 200 accredited imaging systems.

Purpose: From 2010 until July 2016, the EANM Research Ltd. (EARL) FDG-PET/CT accreditation program has collected over 2500 phantom datasets from approximately 200 systems and 150 imaging sites worldwide. The objective of this study is to report the findings and impact of the accreditation program on the participating PET/CT systems.

EANM/EARL harmonization strategies in PET quantification: from daily practice to multicentre oncological studies.

Quantitative positron emission tomography/computed tomography (PET/CT) can be used as diagnostic or prognostic tools (i.e. single measurement) or for therapy monitoring (i.

[I]FP-CIT ENC-DAT normal database: the impact of the reconstruction and quantification methods.

Background: [I]FP-CIT is a well-established radiotracer for the diagnosis of dopaminergic degenerative disorders. The European Normal Control Database of DaTSCAN (ENC-DAT) of healthy controls has provided age and gender-specific reference values for the [I]FP-CIT specific binding ratio (SBR) under optimised protocols for image acquisition and processing. Simpler reconstruction methods, however, are in use in many hospitals, often without implementation of attenuation and scatter corrections.

The impact of reconstruction and scanner characterisation on the diagnostic capability of a normal database for [I]FP-CIT SPECT imaging.

Background: The use of a normal database for [I]FP-CIT SPECT imaging has been found to be helpful for cases which are difficult to interpret by visual assessment alone, and to improve reproducibility in scan interpretation. The aim of this study was to assess whether the use of different tomographic reconstructions affects the performance of a normal [I]FP-CIT SPECT database and also whether systems benefit from a system characterisation before a database is used. Seventy-seven [I]FP-CIT SPECT studies from two sites and with 3-year clinical follow-up were assessed quantitatively for scan normality using the ENC-DAT normal database obtained in well-documented healthy subjects.

Reduction in camera-specific variability in [(123)I]FP-CIT SPECT outcome measures by image reconstruction optimized for multisite settings: impact on age-dependence of the specific binding ratio in the ENC-DAT database of healthy controls.

Purpose: Quantitative estimates of dopamine transporter availability, determined with [(123)I]FP-CIT SPECT, depend on the SPECT equipment, including both hardware and (reconstruction) software, which limits their use in multicentre research and clinical routine. This study tested a dedicated reconstruction algorithm for its ability to reduce camera-specific intersubject variability in [(123)I]FP-CIT SPECT. The secondary aim was to evaluate binding in whole brain (excluding striatum) as a reference for quantitative analysis.

Implementation of the European multicentre database of healthy controls for [(123)I]FP-CIT SPECT increases diagnostic accuracy in patients with clinically uncertain parkinsonian syndromes.

Purpose: Even though [(123)I]FP-CIT SPECT provides high accuracy in detecting nigrostriatal cell loss in neurodegenerative parkinsonian syndromes (PS), some patients with an inconclusive diagnosis remain. We investigated whether the diagnostic accuracy in patients with clinically uncertain PS with previously inconclusive findings can be improved by the use of iterative reconstruction algorithms and an improved semiquantitative evaluation which additionally implemented a correction algorithm for patient age and gamma camera dependency (EARL-BRASS; Hermes Medical Solutions, Sweden).

Methods: We identified 101 patients with inconclusive findings who underwent an [(123)I]FP-CIT SPECT between 2003 and 2010 as part of the diagnostic process of suspected PS at the University of Munich, and re-evaluated these scans using iterative reconstruction algorithms and the new corrected EARL-BRASS.

Association of central serotonin transporter availability and body mass index in healthy Europeans.

Unlabelled: Serotonin-mediated mechanisms, in particular via the serotonin transporter (SERT), are thought to have an effect on food intake and play an important role in the pathophysiology of obesity. However, imaging studies that examined the correlation between body mass index (BMI) and SERT are sparse and provided contradictory results. The aim of this study was to further test the association between SERT and BMI in a large cohort of healthy subjects.

Extrastriatal binding of [¹²³I]FP-CIT in the thalamus and pons: gender and age dependencies assessed in a European multicentre database of healthy controls.

Purpose: Apart from binding to the dopamine transporter (DAT), [(123)I]FP-CIT shows moderate affinity for the serotonin transporter (SERT), allowing imaging of both monoamine transporters in a single imaging session in different brain areas. The aim of this study was to systematically evaluate extrastriatal binding (predominantly due to SERT) and its age and gender dependencies in a large cohort of healthy controls.

Methods: SPECT data from 103 healthy controls with well-defined criteria of normality acquired at 13 different imaging centres were analysed for extrastriatal binding using volumes of interest analysis for the thalamus and the pons.

Validation of CT doses of SPECT/CT and PET/CT hybrid devices: lessons learned.

The aim of the study was to check the validity of computed tomographic (CT) doses exhibited by SPECT/CT and PET/CT hybrid devices. Dose measurements were taken from four SPECT/CT and four PET/CT cameras commercially available from different manufacturers. A calibrated ionization chamber was placed in whole-body or head phantoms for the acquisition of CT images with clinically used parameters.

No difference in striatal dopamine transporter availability between active smokers, ex-smokers and non-smokers using [123I]FP-CIT (DaTSCAN) and SPECT.

Background: Mesolimbic and nigrostriatal dopaminergic pathways play important roles in both the rewarding and conditioning effects of drugs. The dopamine transporter (DAT) is of central importance in regulating dopaminergic neurotransmission and in particular in activating the striatal D2-like receptors. Molecular imaging studies of the relationship between DAT availability/dopamine synthesis capacity and active cigarette smoking have shown conflicting results.

Value of semiquantitative analysis for clinical reporting of 123I-2-β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)nortropane SPECT studies.

Unlabelled: Clinical (123)I-2-β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)nortropane ((123)I-FP-CIT) SPECT studies are commonly performed and reported using visual evaluation of tracer binding, an inherently subjective method. Increased objectivity can potentially be obtained using semiquantitative analysis. In this study, we assessed whether semiquantitative analysis of (123)I-FP-CIT tracer binding created more reproducible clinical reporting.

Automatic semi-quantification of [123I]FP-CIT SPECT scans in healthy volunteers using BasGan version 2: results from the ENC-DAT database.

Purpose: The aim of this study was to assess striatal dopamine transporter (DAT) availability in a large group of normal subjects.

Methods: The study included 122 healthy subjects, aged 18-83 years, recruited in the multicentre 'ENC-DAT' study (promoted by the European Association of Nuclear Medicine). Brain single photon emission computed tomography (SPECT) was acquired by means of dual-head cameras 3 h after [(123)I]FP-CIT administration.

European multicentre database of healthy controls for [123I]FP-CIT SPECT (ENC-DAT): age-related effects, gender differences and evaluation of different methods of analysis.

Purpose: Dopamine transporter (DAT) imaging with [(123)I]FP-CIT (DaTSCAN) is an established diagnostic tool in parkinsonism and dementia. Although qualitative assessment criteria are available, DAT quantification is important for research and for completion of a diagnostic evaluation. One critical aspect of quantification is the availability of normative data, considering possible age and gender effects on DAT availability.

No association between striatal dopamine transporter binding and body mass index: a multi-center European study in healthy volunteers.

Introduction: Dopamine is one among several neurotransmitters that regulate food intake and overeating. Thus, it has been linked to the pathophysiology of obesity and high body mass index (BMI). Striatal dopamine D(2) receptor availability is lower in obesity and there are indications that striatal dopamine transporter (DAT) availability is also decreased.

Leaky gut in patients with diarrhea-predominant irritable bowel syndrome and inactive ulcerative colitis.

Background/aims: Defective epithelial barrier has been implicated in the pathogenesis of irritable bowel syndrome (IBS) and inflammatory bowel diseases. The aim of this study was to investigate gut permeability in patients with inactive ulcerative colitis (UC) and in patients with IBS.

Methods: IBS patients of the diarrhea-predominant (IBS-D) and of the constipation-predominant subgroup (IBS-C), patients with inactive UC and healthy subjects were enrolled.

Calibration of gamma camera systems for a multicentre European ¹²³I-FP-CIT SPECT normal database.

Purpose: A joint initiative of the European Association of Nuclear Medicine (EANM) Neuroimaging Committee and EANM Research Ltd. aimed to generate a European database of [(123)I]FP-CIT single photon emission computed tomography (SPECT) scans of healthy controls. This study describes the characterization and harmonization of the imaging equipment of the institutions involved.

The impact of reconstruction method on the quantification of DaTSCAN images.

Purpose: Reconstruction of DaTSCAN brain studies using OS-EM iterative reconstruction offers better image quality and more accurate quantification than filtered back-projection. However, reconstruction must proceed for a sufficient number of iterations to achieve stable and accurate data. This study assessed the impact of the number of iterations on the image quantification, comparing the results of the iterative reconstruction with filtered back-projection data.