Lessons from two cases of radiation induced skin injuries in fluoroscopic procedures in Bulgaria.

BACKGROUND: Radiation-induced injuries to patient skin as a result of fluoroscopy guided interventional procedures are infrequently reported, often misdiagnosed and there is a need to learn lessons from every injury. METHODS: This paper describes two cases of radiation induced skin injuries that are, to the best of our knowledge, the first ever reported cases from Bulgaria and possibly from Eastern Europe, and would thus have educational value. RESULTS: The important messages from the skin injuries reported here are: lack of awareness among part of the interventional specialists about the potential for radiation induced skin injury, misdiagnosis after injury happened because of lack of awareness and knowledge among general physicians, dermatologists and surgeons who followed up cases of skin injuries; the lack of system to monitor patients with relatively high exposure; the important role played by the medical physicist in diagnosing the injury and overall in initiating actions; the role of training and informational material displayed in interventional facilities. CONCLUSIONS: For avoidance of skin injuries from interventional procedures it is of utmost importance to implement a system that includes (a) regular monitoring of radiation dose parameters of the procedure; (b) established trigger values for reporting;

The mandate and work of ICRP Committee 3 on radiological protection in medicine.

The mandate of Committee 3 of the International Commission on Radiological Protection (ICRP) is concerned with the protection of persons and unborn children when ionising radiation is used in medical diagnosis, therapy, and biomedical research. Protection in veterinary medicine has been newly added to the mandate. Committee 3 develops recommendations and guidance in these areas. The most recent documents published by ICRP that relate to radiological protection in medicine are 'Radiological protection in cone beam computed tomography' (ICRP Publication 129) and 'Radiological protection in ion beam radiotherapy' (ICRP Publication 127). A report in cooperation with ICRP Committee 2 entitled 'Radiation dose to patients from radiopharmaceuticals: a compendium of current information related to frequently used substances' (ICRP Publication 128) has also been published. 'Diagnostic reference levels in medical imaging' (ICRP Publication 135), published in 2017, provides specific advice on the setting and use of diagnostic reference levels for diagnostic and interventional radiology, digital imaging, computed tomography, nuclear medicine, paediatrics, and multi-modality procedures. 'Occupational radiological protection in interventional procedures' was published in March 2018 as ICRP Publication 139. A document on radiological protection in therapy with radiopharmaceuticals is likely to be published in 2018. Work is in progress on several other topics, including appropriate use of effective dose in collaboration with the other ICRP committees, guidance for occupational radiological protection in brachytherapy, justification in medical imaging, and radiation doses to patients from radiopharmaceuticals (an update to ICRP Publication 128). Committee 3 is also considering the development of guidance on radiological protection in medicine related to individual radiosusceptibility, in collaboration with ICRP Committee 1.

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.

Overview of ICRP Committee 3: protection in medicine.

Committee 3 of the International Commission on Radiological Protection (ICRP) develops recommendations and guidance for protection of patients, staff, and the public against radiation exposure when ionising radiation is used for medical diagnosis, therapy, or biomedical research. This paper presents a summary of the work that Committee 3 has accomplished over the past few years, and also describes its current work. The most recent reports published by the Commission that relate to radiological protection in medicine are 'Radiological protection in cone beam computed tomography' (Publication 129), 'Radiation dose to patients from radiopharmaceuticals: a compendium of current information related to frequently used substances' (Publication 128, in cooperation with Committee 2), 'Radiological protection in ion beam radiotherapy' (Publication 127), 'Radiological protection in paediatric diagnostic and interventional radiology' (Publication 121), 'Radiological protection in cardiology' (Publication 120), and 'Radiological protection in fluoroscopically guided procedures outside the imaging department' (Publication 117). A new report on diagnostic reference levels in medical imaging will provide specific advice for interventional radiology, digital imaging, computed tomography, nuclear medicine, paediatrics, and hybrid (multi-modality) imaging procedures, and is expected to be published in 2016. Committee 3 is also working on guidance for occupational radiological protection in brachytherapy, and on guidance on occupational protection issues in interventional procedures, paying particular attention to the 2011 Commission's recommendations on the occupational dose limit for the lens of the eye (Publication 118). Other reports in preparation deal with justification, radiological protection in therapy with radiopharmaceuticals, radiological protection in medicine as related to individual radiosusceptibility, appropriate use of effective dose (in cooperation with other Committees), and guidance for healthcare practitioners on radiological and patient protection. Committee 3 has also suggested specific priorities for research on radiological protection in medicine to the Commission.

Tracking of examination and dose: overview.

This paper reviews the developments in tracking of patient exposures and dose after the earlier paper published in the same journal in 2011. A global survey in which 76 countries responded indicated strong interest in programme and another survey among referring physicians showed vast majority (71.7 %) of physicians expressing that awareness of previous history of CT scans would always or mostly lead them to a better decision on referring patients for CT scans. A sizable number of countries have system of assigning permanent ID to individuals and nearly half of them use this ID in medical records. This can easily permit tracking of exposures. Templates for tracking at different levels of health care have been provided, and experience from a country where tracking is routinely practised has been published.

Radiological protection in computed tomography and cone beam computed tomography.

The International Commission on Radiological Protection (ICRP) has sustained interest in radiological protection in computed tomography (CT), and ICRP Publications 87 and 102 focused on the management of patient doses in CT and multi-detector CT (MDCT) respectively. ICRP forecasted and 'sounded the alarm' on increasing patient doses in CT, and recommended actions for manufacturers and users. One of the approaches was that safety is best achieved when it is built into the machine, rather than left as a matter of choice for users. In view of upcoming challenges posed by newer systems that use cone beam geometry for CT (CBCT), and their widened usage, often by untrained users, a new ICRP task group has been working on radiological protection issues in CBCT. Some of the issues identified by the task group are: lack of standardisation of dosimetry in CBCT; the false belief within the medical and dental community that CBCT is a 'light', low-dose CT whereas mobile CBCT units and newer applications, particularly C-arm CT in interventional procedures, involve higher doses; lack of training in radiological protection among clinical users; and lack of dose information and tracking in many applications. This paper provides a summary of approaches used in CT and MDCT, and preliminary information regarding work just published for radiological protection in CBCT.

Eye dose assessment and management: overview.

Some publications have shown that Hp(0.07) or even Hp(10) can be used as good operational quantities for X-rays in view of difficulties with Hp(3). With increasing awareness, there is tendency to use whatever dosimeter is available with correction factor to estimate eye lens dose. The best position for an eye lens dosimeter has been reported to be at the side of the head nearest to the radiation source, close to the eye. Recent studies have reported eye doses with cone beam CT (CBCT) both for patients and staff, and there are many papers reporting eye lens doses to staff in nuclear medicine. To minimise the dose to eyes, the user can take advantage of a feature of CBCT of projections acquired over an angular span of 180° plus cone angle of the X-ray tube and with tube under scan arcs.

Radiation effects and risks: overview and a new risk perception index.

Uncertainty provides opportunities for differences in perception, and radiation risks at low level of exposures involved in few computed tomography scans fall in this category. While there is good agreement among national and international organisations on risk probability of cancer, risk perception has barely been dealt with by these organisations. Risk perception is commonly defined as the subjective judgment that people make about the characteristics and severity of a risk. Severity and latency are important factors in perception. There is a need to connect all these. Leaving risk perception purely as a subjective judgement provides opportunities for people to amplifying risk. The author postulates a risk perception index as severity divided by latency that becomes determining factor for risk perception. It is hoped that this index will bring rationality in risk perception.

Looking into future: challenges in radiation protection in medicine.

Radiation protection in medicine is becoming more and more important with increasing wider use of X-rays, documentation of effects besides the potential for long-term carcinogenic effects. With computed tomography (CT) likely to become sub-mSv in coming years, positron emission tomography (PET), single photon emission computed tomography (SPECT) and some of the nuclear medical examination will become focus of attraction as high-dose examinations, even though they are less-frequent ones. Clarity will be needed on radiation effects at levels of radiation doses encountered in a couple of CT scans and if effects are really cumulative. There is challenge to develop radiation metrics that can be used as easily as units of temperature and length and avoidance of multiple meaning of a single dose metric. Other challenges include development of biological indicators of radiation dose, transition from dose to a representative phantom to dose to individual patient, system for tracking of radiation exposure history of patient, avoidance of radiation-induced skin injury in patients and radiation cataract in staff, cutting down inappropriate referrals for radiological examinations, confidence building in patient and patient safety in radiotherapy.

IAEA experience in communicating radiation risks through the RPOP website.

The authors report here their successful experience of communicating information to health professionals, patients and the public on benefits and risks of ionising radiation in medical applications. The approaches used have been based on giving importance to clinical benefits against risks, as well as safety in use against risk of use. Communicating brief messages against catchy questions with positive and pragmatic approach resulted in making website on radiation protection of patients (RPOP) as the top website of the world in this area. Credibility of information has been maintained. The results show immense outreach in 213 countries/territories.

Overview of ICRP Committee 3 'Protection in Medicine'.

According to the 2011-2017 strategic plan, Committee 3 develops recommendations and guidance for protection of patients, staff, and the public against radiation exposure when ionising radiation is used for medical diagnosis, therapy, or biomedical research. This paper presents an overview of the work that Committee 3 has accomplished in recent years and describes its current work. The International Commission on Radiological Protection reports dealing with radiological protection in medicine from 2000 to the present cover topics on education and training in radiological protection; preventing accidental exposures in radiation therapy; doses to patients from radiopharmaceuticals; radiation safety aspects of brachytherapy; release of patients after therapy with unsealed radionuclides; and managing radiation dose in interventional radiology, digital radiology, computed tomography, paediatrics, cardiology, and other medical specialties. Current work deals with radiological protection in ion beam therapy, occupational protection in brachytherapy, justification in imaging, radiological protection in cone-beam computed tomography, occupational protection in interventional procedures, diagnostic reference levels for diagnostic and interventional imaging, and an update of an earlier publication on doses to patients and staff from radiopharmaceuticals. Committee 3 is also involved in preparation of a document on effective dose and its use in medicine.

Radiological Protection in Cone Beam Computed Tomography (CBCT). ICRP Publication 129.

The objective of this publication is to provide guidance on radiological protection in the new technology of cone beam computed tomography (CBCT). Publications 87 and 102 dealt with patient dose management in computed tomography (CT) and multi-detector CT. The new applications of CBCT and the associated radiological protection issues are substantially different from those of conventional CT. The perception that CBCT involves lower doses was only true in initial applications. CBCT is now used widely by specialists who have little or no training in radiological protection. This publication provides recommendations on radiation dose management directed at different stakeholders, and covers principles of radiological protection, training, and quality assurance aspects. Advice on appropriate use of CBCT needs to be made widely available. Advice on optimisation of protection when using CBCT equipment needs to be strengthened, particularly with respect to the use of newer features of the equipment. Manufacturers should standardise radiation dose displays on CBCT equipment to assist users in optimisation of protection and comparisons of performance. Additional challenges to radiological protection are introduced when CBCT-capable equipment is used for both fluoroscopy and tomography during the same procedure. Standardised methods need to be established for tracking and reporting of patient radiation doses from these procedures. The recommendations provided in this publication may evolve in the future as CBCT equipment and applications evolve. As with previous ICRP publications, the Commission hopes that imaging professionals, medical physicists, and manufacturers will use the guidelines and recommendations provided in this publication for implementation of the Commission's principle of optimisation of protection of patients and medical workers, with the objective of keeping exposures as low as reasonably achievable, taking into account economic and societal factors, and consistent with achieving the necessary medical outcomes.

A new container geometry for better sensitivity in radiometric measurements.

A new two-compartment liquid scintillation vial system for radiometric measurement has been evolved, such that the light attenuation by the inner vial is minimized. The increase in relative efficiency is over 70% better than in an earlier design. The system is compact and versatile, and is suitable for automated, cumulative, or continuous radiometric measurements.

Site of Tc-99m binding to the red blood cell: concise communication.

The increasing interest in the use of Tc-99m-labeled red blood cells encourages exploration into the site and mechanism of binding of Tc-99m to the RBC components. The components isolated from the labeled red cells were the lipid and protein of the membrane, heme, and the alpha and beta chains of the globin. The binding occurs mainly to the protein moiety, and preferentially to the beta chain of the globin, where the specific activity was found to be 28 +/- 6 times that of the alpha chain. The mechanism of binding is discussed. The role of heme in the binding is not clear.

Transport studies and enzyme assays in mice infected with human Giardia lamblia.

It is well established that Giardia infection causes malabsorption. However, the precise mechanism of such a malabsorption is not known. To investigate this, transport studies, using the tissue accumulation technique, were carried out in mice infected with G. lamblia obtained from human stools. There was a significant fall in the transport of D-glucose, L-alanine and glycine in the infected animals compared with the controls. Kinetics of the D-glucose and glycine transport system were examined by measuring the tissue uptake in the presence of different concentrations of the substrate. For glucose, the affinity constant (Km) for the transport site was the same (4 . 37mM) in normal and infected animals but the maximal transport rate (V max) was considerably reduced in infected animals (158 . 7 mu moles/hr/g tissue) compared with (357 . 1 microgram moles/hr/g tissue) in controls. Results with glycine were similar; the Km was similar in control and infected animals (5 . 7 mM) whereas the V max was reduced in infected animals (27 . 02 microgram moles/hr/g tissue) compared with controls (45 . 5 micrograms moles/hr/g tissue). Analysis of the intestinal enzymes showed a significant decrease in the levels of brush border sucrase, lactase and alkaline phosphatase in infected animals; the cellular enzymes, LDH, GOT and GPT remained unaffected. The observed aberrations in the transport functions and brush border enzymes suggest that G. lamblia causes malabsorption by damaging the epithelial membrane of the enterocyte.

Placental localisation with 99mTc-labelled red blood cells.

The accuracy of placental localisation by radioisotopic scanning using 99mTc-labelled red blood cells has been estimated in 20 patients. The results have been correlated with the findings at delivery by direct and indirect methods. The accuracy of results regarding upper and lower segment insertion of the placenta was 90% in the present study.

A simple and inexpensive clinical whole body counter.

The conventional radioisotope scanner has been used as a whole body counter. The background index of the system is 10.9 counts per minute per ml of sodium iodide crystal. The sensitivity and derived sensitivity parameters have been evaluated and found to be suitable for clinical studies. The optimum parameters for a single detector at two positions above the lying subject have been obtained. It has been found that for the case of 131I measurement it is possible to assay a source located at any point in the body with coefficient of variation less than 5%. To add to the versatility, a fixed geometry for in-vitro counting of large samples has been obtained. The retention values obtained by the whole body counter have been found to correlate with those obtained by in-vitro assay of urine and stool after intravenous administration of 51Cr-albumin.

Evaluation of a simpler technique for in-vivo labelling of red blood cells with 99mTc.

The efficiency of labelling red blood cells with intravenously administered 99mTcO4, by prior oral administration of stannous chloride dihydrate, has been evaluated. Optimum labelling occurred 1 hr after the oral dose of 200 mg of SnCl2.2 H2O and 20 min after the intravenous injection of 99mTcO4. The mechanism of labelling has been shown to be diffusion of 99Tc through the cell membrane followed by binding to haemoglobin in the presence of reducing agent. The in-vivo labelling technique has been found to be useful for the diagnosis of an abdominal mass and for static perfusion studies.

Eye dosimetry in interventional radiology and cardiology: current challenges and practical considerations.

Interventional radiology and cardiology are areas with high potential for risk to eye lens. Accurate assessment of eye dose is one of the most important aspects of correlating doses with observed lens opacities among workers in interventional suites and ascertaining compliance with regulatory limits. The purpose of this paper is to review current approaches and opportunities in eye dosimetry and assess challenges in particular in accuracy and practicality. The possible approaches include practical dosimetry using passive dosemeters or active dosemeters with obvious advantage of active dosimetry. When neither of these is available, other approaches are based on either retrospective dose assessment using scatter radiation dose levels or correlations between patient dose indices and eye doses to the operators. In spite of all uncertainties and variations, estimation of eye dose from patient dose can be accepted as a compromise. Future challenges include development of practical methods for regular monitoring of individual eye doses and development of better techniques to estimate eye dose from measurements at some reference points.

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.