National survey to update the diagnostic reference levels in interventional radiology procedures in Italy: working methodology.

Interventional Radiology (IR) deals with the diagnosis and treatment of various diseases through medically guided imaging. It provides unquestionable benefits to patients, but requires, in many cases, the use of high doses of ionizing radiation with a high impact on radiation risks to patients and to overall dose to the population. The International Commission on Radiological Protection introduced Diagnostic reference levels (DRLs) as an effective tool to facilitate dose verification and optimize protection for patients undergoing radiological procedures. In addition, EURATOM Council Directive 2013/59 and its Italian transposition (Legislative Decree 101/2020) have reiterated that DRLs must be established for many common radiological diagnostic procedures to compare the radiation dose delivered for the same diagnostic examination. Within this framework, Istituto Superiore di Sanità-Italian National Institute of Health (ISS)-, in collaboration with relevant Italian Scientific Societies, has provided documents on DRLs in radiological practices such as diagnostic and IR and diagnostic nuclear medicine. These reference documents enable National Hospitals to comply national regulation. The implementation of DRLs in IR is a difficult task because of the wide distribution of doses to patients even within the same procedure. Some studies have revealed that the amount of radiation in IR procedures is influenced more by the complexity of the procedure than by the weight of the patient, so complexity should be included in the definition of DRLs. For this reason, ISS promoted a survey among a sample of Italian Centers update national DRL in IR procedures with related complexity factors than can be useful for other radiological centers and to standardize the DRLs values. In the present paper the procedural methodology developed by ISS and used for the survey will be illustrated.

A cutoff thyroglobulin value suggestive of distant metastases in differentiated thyroid cancer patients.

Serum thyroglobulin is used as part of the early postoperative assessment of differentiated thyroid cancer (DTC) since there is a clear relationship between an increased risk of recurrence and persistent disease after initial treatment and high postoperative stimulated thyroglobulin (ps-Tg) values. Thus, although ps-Tg above 10-30 ng/mL is considered an independent predictor of worse prognosis, the value that is associated with distant metastases is not defined. Thus, this was our objective. We selected 655 DTC patients from a nuclear medicine department database (Irmandade Santa Casa de Misericórdia de São Paulo, Brazil). All patients had received total thyroidectomy and radioactive iodine (RAI) therapy and had ps-Tg values higher than 10 ng/mL with negative anti-thyroglobulin antibodies. Then, we selected patients who presented post-therapy whole-body scan with pulmonary and/or bone uptake but with no mediastinum or cervical uptake. Patients with negative findings on functional imaging or any doubt on lung/bone uptake were submitted to additional exams to exclude another non-thyroid tumor. Of the 655 patients, 14.3% had pulmonary and 4.4% bone metastases. There was a significant difference in ps-Tg levels between patients with and without metastases (P<0.001). The cutoff value of ps-Tg was 117.5 ng/mL (sensitivity: 70.2%; specificity: 71.7%) for those with lung metastasis, and 150.5 ng/mL (sensitivity: 79.3%; specificity: 85%) for those with bone metastasis. The cutoff value for patients with eitherpulmonary or bone metastasis was 117.5 ng/mL (sensitivity: 70.2%; specificity: 83.7%). Our findings demonstrated that ps-Tg could predict distant metastasis in DTC patients. We identified a cutoff of 117.5 ng/mL with a high negative predictive value of 93.7%.

A cutoff thyroglobulin value suggestive of distant metastases in differentiated thyroid cancer patients

Serum thyroglobulin is used as part of the early postoperative assessment of differentiated thyroid cancer (DTC) since there is a clear relationship between an increased risk of recurrence and persistent disease after initial treatment and high postoperative stimulated thyroglobulin (ps-Tg) values. Thus, although ps-Tg above 10-30 ng/mL is considered an independent predictor of worse prognosis, the value that is associated with distant metastases is not defined. Thus, this was our objective. We selected 655 DTC patients from a nuclear medicine department database (Irmandade Santa Casa de Misericórdia de São Paulo, Brazil). All patients had received total thyroidectomy and radioactive iodine (RAI) therapy and had ps-Tg values higher than 10 ng/mL with negative anti-thyroglobulin antibodies. Then, we selected patients who presented post-therapy whole-body scan with pulmonary and/or bone uptake but with no mediastinum or cervical uptake. Patients with negative findings on functional imaging or any doubt on lung/bone uptake were submitted to additional exams to exclude another non-thyroid tumor. Of the 655 patients, 14.3% had pulmonary and 4.4% bone metastases. There was a significant difference in ps-Tg levels between patients with and without metastases (P<0.001). The cutoff value of ps-Tg was 117.5 ng/mL (sensitivity: 70.2%; specificity: 71.7%) for those with lung metastasis, and 150.5 ng/mL (sensitivity: 79.3%; specificity: 85%) for those with bone metastasis. The cutoff value for patients with eitherpulmonary or bone metastasis was 117.5 ng/mL (sensitivity: 70.2%; specificity: 83.7%). Our findings demonstrated that ps-Tg could predict distant metastasis in DTC patients. We identified a cutoff of 117.5 ng/mL with a high negative predictive value of 93.7%.

ICRP Publication 139: Occupational Radiological Protection in Interventional Procedures.

Abstract: In recent publications, such as Publications 117 and 120, the Commission provided practical advice for physicians and other healthcare personnel on measures to protect their patients and themselves during interventional procedures. These measures can only be effective if they are encompassed by a framework of radiological protection elements, and by the availability of professionals with responsibilities in radiological protection. This framework includes a radiological protection programme with a strategy for exposure monitoring, protective garments, education and training, and quality assurance of the programme implementation. Professionals with responsibilities in occupational radiological protection for interventional procedures include: medical physicists; radiological protection specialists; personnel working in dosimetry services; clinical applications support personnel from the suppliers and maintenance companies; staff engaged in training, standardisation of equipment, and procedures; staff responsible for occupational health; hospital administrators responsible for providing financial support; and professional bodies and regulators. This publication addresses these elements and these audiences, and provides advice on specific issues, such as assessment of effective dose from dosimeter readings when an apron is worn, estimation of exposure of the lens of the eye (with and without protective eyewear), extremity monitoring, selection and testing of protective garments, and auditing the interventional procedures when occupational doses are unusually high or low (the latter meaning that the dosimeter may not have been worn).

Radiation-Induced Lens Opacities among Interventional Cardiologists: Retrospective Assessment of Cumulative Eye Lens Doses.

This study describes the retrospective lens dose calculation methods developed and applied within the European epidemiological study on radiation-induced lens opacities among interventional cardiologists. While one approach focuses on self-reported data regarding working practice in combination with available procedure-specific eye lens dose values, the second approach focuses on the conversion of the individual whole-body dose to eye lens dose. In contrast with usual dose reconstruction methods within an epidemiological study, a protocol is applied resulting in an individual distribution of possible cumulative lens doses for each recruited cardiologist, rather than a single dose estimate. In this way, the uncertainty in the dose estimate (from measurement uncertainty and variability among cardiologists) is represented for each individual. Eye lens dose and whole-body dose measurements have been performed in clinical practice to validate both methods, and it was concluded that both produce acceptable results in the framework of a dose-risk evaluation study. Optimal results were obtained for the dose to the left eye using procedure-specific lens dose data in combination with information collected on working practice. This method has been applied to 421 interventional cardiologists resulting in a median cumulative eye lens dose of 15.1 cSv for the left eye and 11.4 cSv for the right eye. From the individual cumulative eye lens dose distributions obtained for each cardiologist, maxima up to 9-10 Sv were observed, although with low probability. Since whole-body dose values above the lead apron are available for only a small fraction of the cohort and in many cases not for the entire working career, the second method has only been used to benchmark the results from the first approach. This study succeeded in improving the retrospective calculation of cumulative eye lens doses in the framework of radiation-induced risk assessment of lens opacities, but it remains dependent on self-reported information, which is not always reliable for early years. However, the calculation tools developed can also be used to make an assessment of the eye lens dose in current practice.

ICRP Publication 135: Diagnostic Reference Levels in Medical Imaging.

Abstract ­: The International Commission on Radiological Protection (ICRP) first introduced the term 'diagnostic reference level' (DRL) in 1996 in Publication 73. The concept was subsequently developed further, and practical guidance was provided in 2001. The DRL has been proven to be an effective tool that aids in optimisation of protection in the medical exposure of patients for diagnostic and interventional procedures. However, with time, it has become evident that additional advice is needed. There are issues related to definitions of the terms used in previous guidance, determination of the values for DRLs, the appropriate interval for re-evaluating and updating these values, appropriate use of DRLs in clinical practice, methods for practical application of DRLs, and application of the DRL concept to newer imaging technologies. This publication is intended as a further source of information and guidance on these issues. Some terminology has been clarified. In addition, this publication recommends quantities for use as DRLs for various imaging modalities, and provides information on the use of DRLs for interventional procedures and in paediatric imaging. It suggests modifications in the conduct of DRL surveys that take advantage of automated reporting of radiation-dose-related quantities, and highlights the importance of including information on DRLs in training programmes for healthcare workers. The target audience for this publication is national, regional, and local authorities; professional societies; and facilities that use ionising radiation for medical purposes, and responsible staff within these facilities. A full set of the Commission's recommendations is provided.

Miniaturized implantable sensors for in vivo localized temperature measurements in mice during cold exposure.

We report on in vivo temperature measurements performed in mice at two specific sites of interest in the animal body over a period of several hours. In particular, the aim of this work was to monitor mouse metabolism during cold exposure, and to record possible temperature differences between the body temperature measured in the abdomen and the temperature of the brown adipose tissue (BAT) situated in the interscapular area. This approach is of biological interest as it may help unravelling the question whether biochemical activation of BAT is associated with local increase in metabolic heat production. For that purpose, miniaturized thermistor sensors have been accurately calibrated and implanted in the BAT and in the abdominal tissue of mice. After 1 week of recovery from surgery, mice were exposed to cold (6 °C) for a maximum duration of 6 h and the temperature was acquired continuously from the two sensors. Control measurements with a conventional rectal probe confirmed good performance of both sensors. Moreover, two different mouse phenotypes could be identified, distinguishable in terms of their metabolic resistance to cold exposure. This difference was analyzed from the thermal point of view by computational simulations. Our simple physical model of the mouse body allowed to reproduce the global evolution of hypothermia and also to explain qualitatively the temperature difference between abdomen and BAT locations. While with our approach, we have demonstrated the importance and feasibility of localized temperature measurements on mice, further optimization of this technique may help better identify local metabolism variations.

EUTEMPE-RX, an EC supported FP7 project for the training and education of medical physics experts in radiology.

The core activity of the medical physics expert (MPE) is to ensure optimal use of ionising radiation in healthcare. It is essential that these healthcare professionals are trained to the highest level, defined as European Qualifications Framework for Lifelong Learning (EQF) level 8 by the European Commission's Radiation Protection Report 174 'Guidelines on the MPE'. The main objective of the EUTEMPE-RX project is to provide a model training scheme that allows the medical physicist in diagnostic and interventional radiology (D&IR) to reach this high level. A European network of partners was brought together in this FP7 EC project to ensure sufficient expertise in all aspects of the subject and to create a harmonised course programme. Targeted participants are medical physicists in D&IR in hospitals, engineers and scientists in medical device industries and officers working in regulatory authorities. Twelve course modules will be developed at EQF level 8, with radiation safety and diagnostic effectiveness being prevalent subjects. The modules will combine online with face-to-face teaching using a blended learning approach.

The European Federation of Organisations for Medical Physics Policy Statement No 14: the role of the Medical Physicist in the management of safety within the magnetic resonance imaging environment: EFOMP recommendations.

This European Federation of Organisations for Medical Physics (EFOMP) Policy Statement outlines the way in which a Safety Management System can be developed for MRI units. The Policy Statement can help eliminate or at least minimize accidents or incidents in the magnetic resonance environment and is recommended as a step towards harmonisation of safety of workers, patients, and the general public regarding the use of magnetic resonance imaging systems in diagnostic and interventional procedures.

Radiation doses in cerebral perfusion computed tomography: patient and phantom study.

The purpose of this study was to investigate radiation doses in cerebral perfusion computed tomography (CT) examination. As a part of routine patient monitoring, data were collected on patients in terms of the skin dose and CT dose index (CTDIvol) and dose-length product (DLP) values. For the estimation of the dose to the lens a phantom study was performed. Dose values for skin and lens were below the threshold for deterministic effects. The results were also compared with already published data. For better comparison, the effective dose was also estimated. The values collected on patients were in the ranges 230-680 mGy for CTDI and 2120-2740 mGy cm for DLP, while the skin dose and estimated effective dose were 340-800 mGy and 4.9-6.3 mSv, respectively. These values measured in the phantom study were similar, while the doses estimated to the lens were 53 and 51 mGy for the right and left lens, respectively.

ICRP PUBLICATION 120: Radiological protection in cardiology.

Cardiac nuclear medicine, cardiac computed tomography (CT), interventional cardiology procedures, and electrophysiology procedures are increasing in number and account for an important share of patient radiation exposure in medicine. Complex percutaneous coronary interventions and cardiac electrophysiology procedures are associated with high radiation doses. These procedures can result in patient skin doses that are high enough to cause radiation injury and an increased risk of cancer. Treatment of congenital heart disease in children is of particular concern. Additionally, staff(1) in cardiac catheterisation laboratories may receive high doses of radiation if radiological protection tools are not used properly. The Commission provided recommendations for radiological protection during fluoroscopically guided interventions in Publication 85, for radiological protection in CT in Publications 87 and 102, and for training in radiological protection in Publication 113 (ICRP, 2000b,c, 2007a, 2009). This report is focused specifically on cardiology, and brings together information relevant to cardiology from the Commission's published documents. There is emphasis on those imaging procedures and interventions specific to cardiology. The material and recommendations in the current document have been updated to reflect the most recent recommendations of the Commission. This report provides guidance to assist the cardiologist with justification procedures and optimisation of protection in cardiac CT studies, cardiac nuclear medicine studies, and fluoroscopically guided cardiac interventions. It includes discussions of the biological effects of radiation, principles of radiological protection, protection of staff during fluoroscopically guided interventions, radiological protection training, and establishment of a quality assurance programme for cardiac imaging and intervention. As tissue injury, principally skin injury, is a risk for fluoroscopically guided interventions, particular attention is devoted to clinical examples of radiation-related skin injuries from cardiac interventions, methods to reduce patient radiation dose, training recommendations, and quality assurance programmes for interventional fluoroscopy.

[Repetitive transcranial magnetic stimulation in major depression: response factor]. / Stimulation magnétique transcrânienne répétée dans la prise en charge des épisodes dépressifs majeurs : facteurs prédictifs de réponse thérapeutique.

OBJECTIVE: Repetitive transcranial magnetic stimulation (rTMS) is a brain stimulation technique that has been investigated as a novel treatment for psychiatric disorders, notably in major depression, and has shown statistically significant effects. The authors found it necessary to propose an up-to-date review of positive predictors for antidepressive response to repetitive transcranial magnetic stimulation. METHOD: Based on an exhaustive consultation of Medline data, supplemented by a manual research, only works evaluating response factors of rTMS in major depression were retained. RESULTS: Twenty-nine studies were retained, including meta-analyses, reviews, randomized controlled trials and open trials. The most concordant data clearly indicate that a high score of treatment resistance, a long duration of current episode, advanced age, and psychotic symptoms are negative predictors for treatment response to rTMS. In the older patients, menopausal women are especially concerned. However, some parameters should be adapted to the degree of cortical atrophy such as intensity of stimulation or total number of rTMS sessions. Previous response to rTMS therapy seems to be a good predictor contrary to non-response to electroconvulsive therapy. Adjunctive antidepressant treatment shows greater responsiveness to rTMS contrary to benzodiazepine or anticonvulsant treatment. To our knowledge, no study compares unipolar and bipolar depression, the profile of depression is not established yet. Imaging studies show that TMS antidepressant responders differed from non-responders in inferior frontal activity, at baseline, and even more so following treatment. Furthermore, reduced baseline cerebral metabolism in cerebellar, temporal, anterior cingulate and occipital regions of the brain was correlated with improvement after two weeks of fast (20Hz) left dorsolateral prefrontal cortex (DLPFC) rTMS. Additionally, a right frontal region emerges with divergent polarity in the metabolic prediction of response to low rTMS. Inhibiting right DLPFC or stimulating DLPFC shows similar results, the choice on the side of stimulation does not seem determining. Bilateral stimulation for the moment does not seem superior to unilateral stimulation. Parameters of stimulation associated with effectiveness of rTMS are an intensity of stimulation higher than 100% of the motor threshold, a number of stimulations per sessions superior to 1000, and a full number of days of treatment greater than 10. DISCUSSION: Parameters of stimulation must be adapted according to the treated patients. For example, older patients who present cortical atrophy need higher intensity of stimulation. Other criteria could influence effectiveness of rTMS in the same way. Would it be necessary, for example, to adapt the duration or the intensity of stimulation according to the severity of the depressive episode or its duration of evolution? Do antecedents of resistance to a pharmacological treatment oblige us to stimulate differently? Few studies exceed 10 days of treatment; will longer duration of treatment be more effective? Also, we did not find any data on the interest of maintenance treatment among responders. Should the characteristics of the depressive disorder or its evolution require maintenance treatment? What will be its rhythm and its duration? Should we adapt rTMS parameters to abnormalities highlighted by functional neuroimagery? The prospects for work remain numerous.

Insight into illness, neurocognition and quality of life in schizophrenia.

OBJECTIVE: The aim of this study was to assess the impact of insight into illness on self-reported quality of life (QoL) for patients with schizophrenia. METHODS: This cross-sectional study was conducted in the psychiatric department of a French public university teaching hospital. The data collected included socio-demographic information, clinical characteristics, medications, cognitive performance assessments, insight into illness, and the S-QoL 18. A multivariate analysis using multiple linear regressions was performed to determine variables potentially associated with QoL levels. RESULTS: One hundred and thirteen outpatients with stable schizophrenia were enrolled in our study. Significant associations were found between QoL and socio-demographic characteristics: a higher QoL was associated with marital status (in couple) and employment. Concerning insight into illness, lower QoL levels were associated with better awareness of the mental disorder, whereas higher QoL levels were associated with better awareness of positive and negative symptoms. Elementary neuropsychological measures were not statistically associated with QoL. CONCLUSION: Insight into illness, marital status and employment were the most important features associated with QoL, whereas there was no evidence that elementary neurocognition directly influenced QoL. The different facets of insight into illness should be considered to guide the development of specific interventions intended to improve QoL. Moreover, this study highlights the need for clinicians to pay more attention to the personal impact of schizophrenia, especially upon family life and work.

SU-E-J-130: Study of the Image Quality Degradation in Phase-Based 4DCT Imaging for Radiation Oncology.

PURPOSE: Four-dimensional computed tomography (4DCT) integrated into radiation imaging system is a useful tool for accurate targeting. 4DCT has the ability to minimize breathing related artefacts compared to conventional CT but irregular breathing and large tumour motion may cause inappropriate reconstruction. Our aim is to estimate the image quality degradation of 4DCT and to assess the clinical consequences. METHODS: The performance of the respiratory gating system of the multi-slice CT-simulator Brilliance Big Bore was evaluated employing one-dimensional moving phantom. The binning algorithm was phased-based. 4DCT scans of the test-phantom were acquired applying periodic motion patterns characterized by amplitude and frequency spanning a clinically range and also irregular waveforms simulating realistic breathing cycles. The internal spherical objects of the moving phantom were contoured using semiautomatic segmentation for evaluating uncertainties in volume delineation and motion amplitude calculation. Motion amplitude was determined by a specially written MATLAB program. Afterwards we investigated the influence of the image distortions on the targeting and the consequences of the related uncertainties on the calculated dose distribution of the tumour and the lungs in a group of five lung-cancer patients. RESULTS: The results obtained with the phantom show that 4DCT imaging is still affected by distortions due to residual motion. The inaccuracies are mainly related to the amplitude (R2=0.99, R2=0.97 for 20 mm-dia sphere and 10 mm-dia sphere, respectively) and to the oscillation frequency (R2=0.87 for 20 mm-dia sphere, R2=0.96 for 10 mm-dia sphere) of simulated respiratory cycle and can cause both underestimation and overestimation of the real tumour motion amplitude with an average difference between real and calculated amplitude of about 10%. CONCLUSIONS: The resulting inaccuracies on the internal tumour volume delineated do not have significant clinical consequences on lung doses but they could be important on tumour dose distribution if they imply underestimation of the real tumour motion.

International project on individual monitoring and radiation exposure levels in interventional cardiology.

Within the Information System on Occupational Exposure in Medicine, Industry and Research (ISEMIR), a new International Atomic Energy Agency initiative, a Working Group on interventional cardiology, aims to assess staff radiation protection (RP) levels and to propose an international database of occupational exposures. A survey of regulatory bodies (RBs) has provided information at the country level on RP practice in interventional cardiology (IC). Concerning requirements for wearing personal dosemeters, only 57 % of the RB specifies the number and position of dosemeters for staff monitoring. Less than 40 % of the RBs could provide occupational doses. Reported annual median effective dose values (often <0.5 mSv) were lower than expected considering validated data from facility-specific studies, indicating that compliance with continuous individual monitoring is often not achieved in IC. A true assessment of annual personnel doses in IC will never be realised unless a knowledge of monitoring compliance is incorporated into the analysis.

A pilot study exploring the possibility of establishing guidance levels in x-ray directed interventional procedures.

This article summarizes the dosimetric results of an International Atomic Energy Agency coordinated research program to investigate the feasibility of adopting guidance levels for invasive coronary artery procedures. The main study collected clinical data from hospitals located in five countries. A total of 2265 coronary angiograms (CA) and 1844 percutaneous coronary interventions (PCI) were analyzed. Substudies evaluated the dosimetric performance of 14 fluoroscopes, skin dose maps obtained using film, the quality of CA procedures, and the complexity of PCI procedures. Kerma-area product (PKA) guidance levels of 50 and 125 Gy cm2 are suggested for CA and PCI procedures. These levels should be adjusted for the complexity of the procedures performed in a given institution.

Count-rate analysis from clinical scans in PET with LSO detectors.

The purpose of optimising the acquisition parameters in positron emission tomography is to improve the quality of the diagnostic images. Optimisation can be done by maximising the noise equivalent count rate (NECR) that in turn depends on the coincidence rate. For each bed position the scanner records coincidences and singles rates. For each patient, the true, random and scattered coincidences as functions of the single count rate(s) are determined by fitting the NEMA (National Electrical Manufacturers Association) 70 cm phantom count rate curves to measured clinical points. This enables analytical calculation of the personalised PNECR [pseudo NECR(s)] curve, linked to the NECR curve. For central bed positions, missing activity of approximately 70% is estimated to get maximum PNECR (PNECR(max)), but the improvement in terms of signal-toz-noise ratio would be approximately 15%. The correlation between patient weight and PNECR(max) is also estimated to determine the optimal scan duration of a single bed position as a function of patient weight at the same PNEC. Normalising the counts at PNECR(max) for the 70 kg patient, the bed duration for a 90 kg patient should be 230 s, which is approximately 30% longer. Although the analysis indicates that the fast scanner electronics allow using higher administered activities, this would involve poor improvement in terms of NECR. Instead, attending to higher bed duration for heavier patients may be more useful.

An international calibration of Kerma-Area Product meters for patient dose optimisation study.

The results of international calibration of Kerma Area Product (KAP) meters for European SENTINEL survey on patient dose optimisation of cardiac and interventional radiology practice are presented. Twelve countries were involved in the study. An investigation was conduced on 25 KAP meters fitted to undercouch X-ray tubes; 13 KAP meters were installed on cardiac units and the remaining 12 on interventional ones. The simplified calibration method has been applied, consisting of KAP estimation by multiplying the air kerma at the centre of the X-ray field by the irradiated area. The obtained values of calibration factors range from 0.4 to 0.9 and from 0.4 to 0.8 for KAP meters installed on cardiac and interventional units, respectively. They account also for table and mattress attenuation. For air kerma assessment, measurements with thermoluminescent dosemeters have been applied and when possible compared against an additional reference dosemeter. As the result of the investigation, the importance of calibration of KAP meters in clinical conditions that include mattress and table attenuation has been recognised.