Provision of Italian diagnostic reference levels for diagnostic and interventional radiology

OBJECTIVES

The diagnostic reference level (DRL) is a useful tool for the optimisation of medical exposures. Thus, a Working Party coordinated by the Italian National Institute of Health and the National Workers Compensation Authority has been formed to provide Italian DRLs, for both diagnostic and interventional procedures, to be used as appropriate for the implementation of the 2013/59 European Directive into the national regulation.

MATERIALS AND METHODS

The multidisciplinary Working Party was formed by professionals involved in diagnostic and interventional radiology medical exposures and started from a critical revision of both the literature and the results of previous Italian surveys. The procedures were divided into five sections for adult (projection radiography, mammography, diagnostic fluoroscopy, CT and interventional radiology) and two sections for paediatric patients (projection radiography and CT). The provided DRL values have been identified for "normal" adult patients and for age-classes of paediatric patients.

RESULTS

Some of the DRL values provided by the Working Party are reported in this study as an example, divided by adult/paediatric patients, radiological technique and examination: specifically, DRLs for new radiological practices and new dose quantities as DRLs metric were introduced. The median value (rather than the mean) for each procedure, derived from a sample of patients, has to be compared with the corresponding DRL value, and dosimetric data related to a minimum number of patients should be collected for each examination.

CONCLUSIONS

The approach to the definition and use of DRLs through guidelines of national Authorities in collaboration with scientific Associations should simplify the periodical updating and could be useful for keeping the optimisation of medical exposures faithful to the development of radiological practice.

Diagnostic Reference Levels, Deterministic and Stochastic Risks in Pediatric Interventional Cardiology Procedures

To establish diagnostic reference levels (DRLs) and investigate deterministic and stochastic risks in pediatric interventional cardiology (IC) procedures. Exposure parameters were retrospectively reviewed for 373 patients treated between May 2016 and November 2018 at a single specialized hospital. Weight specific DRLs were derived for pediatric IC procedures. Additionally, peak skin dose (Dskin,max) was measured using thermoluminescent dosimeters for a sample of 7 diagnostic and 43 therapeutic procedures. Finally, using PCXMC software, organ doses were computed and the risk of exposure-induced cancer death (REID) was estimated using the risk models of the Biological Effects of Ionizing Radiation VII committee. DRLs for ventricular septal defect (VSD) occlusions, lacking in the literature, in terms of air kerma at patient entrance reference point (388 and 629 mGy) and total air kerma-area product (28 and 61 Gycm) were proposed for patients weight-groups 5 - < 15 kg and 15 - < 30 kg, respectively. The mean (range) Dskin,max was 15 (1-30) mGy and 94 (1-491) mGy for diagnostic and therapeutic procedures, respectively. Meanwhile, VSD occlusion involved the highest organ doses where the lungs, liver, stomach, and breasts mean doses were 57, 37, 6, and 10 mGy, respectively, and the associated REID were 0.5% and 0.3% in female and male patients, respectively. DRLs were proposed for pediatric IC procedures; these will help optimize patient exposure. Dskin,max values were lower than the 2 Gy threshold for skin injuries. Pediatric organ doses and the REID were the highest during VSD occlusion and may be critical for repetitive procedures.

Signal and contrast to noise ratio evaluation of fluoroscopic loops for interventional fluoroscope quality control

Modern fluoroscopes pose a challenge for the clinical physicist for annual testing and continued upkeep. These fluoroscopes are critical to providing care to patients for complex interventions, and continue to evolve in automated image quality adjustments. Few tools in software or hardware currently exist to assist the physicist or technologist in gauging fluoroscope constancy or readiness for procedures. Many modalities such as mammography, computed tomography or even magnetic resonance imaging are much more evolved with respect to testing or quality control. In this work we sought to provide simple reproducible tools and methods for spot evaluating or continued quality testing of interventional fluoroscopes.

Local DRLs and automated risk estimation in paediatric interventional cardiology

Introduction

Cardiac catheterization procedures result in high radiation doses and often multiple procedures are necessary for congenital heart disease patients. However, diagnostic reference levels (DRL) remain scarce. Our first goal was finding the optimal DRL parameter and determining appropriate DRLs. The second goal was to calculate organ doses (OD), effective doses (ED) and lifetime attributable risks (LAR) per procedure and to provide conversion factors based on dose area product (DAP).

Materials and methods

DRLs are calculated for each procedure type, as the 75^th percentile of the cumulative value per procedure from the corresponding parameter. All irradiation events in the DICOM Structured Reports were automatically processed and simulated using PCXMC, resulting in OD, ED and LAR. Using a Kruskal Wallis H test and subsequent pairwise comparisons, differences in median values of the DRL parameter between procedure types were assessed.

Results

Linear regression showed a strong correlation and narrow confidence interval between DAP and product of body weight and fluoroscopy time (BWxFT), even when all procedures (diagnostic and interventional) are combined. Only 15% of the pairwise comparisons were statistically significant for DAP normalized to BWxFT (DAP_BWxFT). The latter pairs contained less frequent procedure types with significant outliers. For DAP normalized to BW (DAP_BW), 38% of the pairwise comparisons showed statistically significant differences. Conversion factors from DAP_BW to OD and ED were reported for various weight groups, due to the higher correlation between DAP_BW and both OD and ED than between DAP and both OD and ED.

Conclusions

The P75 of DAP_BWxFT for all procedures combined serves as an appropriate DRL value. This facilitates local DRL determination in smaller paediatric centres, which often have insufficient data to produce appropriate DRLs for different procedure types. Conversion factors are more reliable starting from DAP_BW instead of DAP and should be used according to the appropriate BW group.

SURVEY OF KEY RADIATION SAFETY PRACTICES IN INTERVENTIONAL RADIOLOGY: AN IRISH AND ENGLISH STUDY

Interventional radiology is a rapidly evolving speciality with potential to deliver high patient radiation doses, as a result high standards of radiation safety practice are imperative. IR radiation safety practice must be considered before during and after procedures through appropriate patient consent, dose monitoring and patient follow-up. This questionnaire-based study surveyed fixed IR departments across Ireland and England to establish clinical practice in relation to radiation safety. Pre-procedure IR patient consent includes all radiation effects in 11% of cases. The patient skin dose surrogate parameter of Kerma to air at a reference point (Kar) is under-reported. Only 39% of respondents use a substantial radiation dose level and inform patients after these have been reached. Poor compliance with unambiguous, readily available best practice guidance was observed throughout highlighting patient communication, patient dose quantification and subsequent patient dose management concerns.

Simple preoperative radiation safety interventions significantly lower radiation doses during central venous line placement in children

PURPOSE

The purpose of this study was to reduce radiation exposure during pediatric central venous line (CVL) placement by implementing a radiation safety process including a radiation safety briefing and a job-instruction model with a preradiation time-out.

METHODS

We reviewed records of all patients under 21 who underwent CVL placement in the operating room covering 22 months before the intervention through 10 months after 2013-2016. The intervention consisted of a radiation safety briefing by the surgeon to the intraoperative staff before each case and a radiation safety time-out. We measured and analyzed the dose area product (DAP), total radiation time pre- and postintervention, and the use of postprocedural chest radiograph.

RESULTS

100 patients with valid DAP measurements were identified for analysis (59 preintervention, 41 postintervention). Following implementation of the radiation safety process, there was a 79% decrease in median DAP (61.4 vs 13.1 rad*cm², P < 0.001) and a 73% decrease in the median radiation time (28 vs 7.6 s, P < 0.001). Additionally, there was a significant reduction in use of confirmatory CXR (95% vs 15%, P < 0.01).

CONCLUSION

A preoperative radiation safety briefing and a radiation safety time-out supported by a job-instruction model were effective in significantly lowering the absorbed doses of radiation in children undergoing CVL insertion.

TYPE OF STUDY

Case-control study.

LEVEL OF EVIDENCE

Level III.

Occupational radiation exposure to nursing staff during cardiovascular fluoroscopic procedures: A review of the literature

Fluoroscopy is a method used to provide real time x-ray imaging of the body during medical procedures to assist with medical diagnosis and treatment. Recent technological advances have seen an increase in the number of fluoroscopic examinations being performed. Nurses are an integral part of the team conducting fluoroscopic investigations and are often located close to the patient resulting in an occupational exposure to radiation. The purpose of this review was to examine recent literature which investigates occupational exposure received by nursing staff during cardiovascular fluoroscopic procedures. Articles published between 2011 and 2017 have been searched and comprehensively reviewed on the referenced medical search engines. Twenty-four relevant studies were identified among which seventeen investigated nursing dose comparative to operator dose. Seven researched the effectiveness of interventions in reducing occupational exposure to nursing staff. While doctors remain at the highest risk of exposure during procedures, evidence suggests that nursing staff may be at risk of exceeding recommended dose limits in some circumstances. There is also evidence of inconsistent use of personal protection such as lead glasses and skull caps by nursing staff to minimize radiation exposure. Conclusions: The review has highlighted a lack of published literature focussing on dose to nurses. There is a need for future research in this area to inform nursing staff of factors which may contribute to high occupational doses and of methods for minimizing the risk of exposure, particularly regarding the importance of utilizing radiation protective equipment.

[Efficacy of percutaneous atrial septal defect closure guided by transesophageal echocardiography in children]

OBJECTIVE

To compare the efficacy of percutaneous atrial septal defect (ASD) closure guided by transesophageal echocardiography (TEE) or guided by fluoroscopy in pediatric patients.

METHODS

Medical records of patients who underwent percutaneous ASD closure in the Children's Hospital, Zhejiang University School of Medicine from January 2017 to March 2018 were reviewed. There were 120 patients whose procedures were guided by TEE (TEE group), and 125 patients who had their procedures guided by fluoroscopy (fluoroscopy group). The performance of surgery, efficacy and postoperative complications were compared between two groups.

RESULTS

Percutaneous ASD closure was successful in all patients. The operation time was shorter in the TEE group than that in fluoroscopy group[(20±14) min vs. (29±11) min, t=-7.939, P<0.05]. The size of the defect was larger in the TEE group than that of fluoroscopy group[(11±4) mm vs. (9±4) mm, t=2.512, P<0.05], but there was no significant difference in the sizes of occluder and occluder sheath between two groups (all P>0.05). No residual shunt, occluder shedding or displacement, severe arrhythmia or pericardial effusion were observed in either group. The incidence rates of fever, cough and diarrhea were not statistically different between two groups (all P>0.05).

CONCLUSIONS

There was no significant difference in the outcome of percutaneous ASD closure guided by TEE or by fluoroscopy, but the procedure guided by TEE may reduce the operation time and can evaluate the size of ASD more accurately without involving radiation exposure, contrast agents use and large digital subtraction equipment.

DOSE AREA PRODUCT VALUES OF FLUOROSCOPICALLY GUIDED PAIN MANAGEMENT PROCEDURES: COMPARISON OF A BELGIAN TEACHING HOSPITAL WITH NATIONAL DIAGNOSTIC REFERENCE LEVELS

In 2011, national diagnostic reference levels (DRLs) were proposed for pain management fluoroscopic procedures in Belgium. The primary goal of this work is to compare the dose area product values (DAP) recorded at the Saint-Luc University Hospital to these DRLs. From 2012 to 2015, 7664 interventional pain management procedures (4740 epidural, 2097 medial branch and 807 transforaminal infiltrations) were performed. Uni/multivariable analyses were done regarding the influence of different factors. The fluoroscopy duration and the DAP are lower to the DRLs (p < 0.001). From 7644 procedures' DAP, 1431 (18.7%) were higher than the DRLs: 1397 epidural (29.5%), 16 medial branch (0.8%) and 18 transforaminal infiltrations (2.2%) (p < 0.001 between procedures). The main factor that significantly modifies DAP, as duration, is the practitioner. Additionally, we obtained [IQR: 25-75] values for epidural [0.0174-0.055 mGy m2], medial branch block [0.0194-0.0472] and transforaminal infiltrations [0.0499-0.1067 mGy m2] (p < 0.05 vs. DRLs, respectively, 0.05, 0.25 and 0.3 mGy m2). Systematic use of contrast confirmation significantly increases DAP (p < 0.001). This retrospective analysis shows differences in DAP, mainly driven by the practitioner. This suggests the existence of modifiable factors. Programs aiming to determine these factors to reduce this DAP are justified.

Radiation Safety in Children With Congenital and Acquired Heart Disease: A Scientific Position Statement on Multimodality Dose Optimization From the Image Gently Alliance

There is a need for consensus recommendations for ionizing radiation dose optimization during multimodality medical imaging in children with congenital and acquired heart disease (CAHD). These children often have complex diseases and may be exposed to a relatively high cumulative burden of ionizing radiation from medical imaging procedures, including cardiac computed tomography, nuclear cardiology studies, and fluoroscopically guided diagnostic and interventional catheterization and electrophysiology procedures. Although these imaging procedures are all essential to the care of children with CAHD and have contributed to meaningfully improved outcomes in these patients, exposure to ionizing radiation is associated with potential risks, including an increased lifetime attributable risk of cancer. The goal of these recommendations is to encourage informed imaging to achieve appropriate study quality at the lowest achievable dose. Other strategies to improve care include a patient-centered approach to imaging, emphasizing education and informed decision making and programmatic approaches to ensure appropriate dose monitoring. Looking ahead, there is a need for standardization of dose metrics across imaging modalities, so as to encourage comparative effectiveness studies across the spectrum of CAHD in children.

Changing Patterns in the Performance of Fluoroscopically Guided Interventional Procedures and Adherence to Radiation Safety Practices in a U.S. Cohort of Radiologic Technologists

OBJECTIVE

Information is limited on changes over time in the types of fluoroscopically guided interventional procedures performed and associated radiation safety practices used by radiologic technologists.

MATERIALS AND METHODS

Our study included 12,571 U.S. radiologic technologists who were certified for at least 2 years in 1926-1982 and who reported in a 2012-2013 survey that they ever performed or assisted with fluoroscopically guided interventional procedures. They completed a mailed questionnaire in 2013-2014 describing their detailed work practices for 21 fluoroscopically guided interventional procedures and associated radiation safety practices from the 1950s through 2009.

RESULTS

Overall, the proportion of technologists who reported working with therapeutic fluoroscopically guided interventional procedures, including percutaneous coronary interventions, increased over time, whereas the proportion of technologists who worked with diagnostic fluoroscopically guided interventional procedures, including diagnostic cardiovascular catheterization and neuroangiographic procedures, decreased. We also observed substantial increases in the median number of times per month that technologists worked with diagnostic cardiovascular catheterizations and percutaneous coronary interventions. In each time period, most technologists reported consistently (≥ 75% of work time) wearing radiation monitoring badges and lead aprons during fluoroscopically guided interventional procedures. However, fewer than 50% of the technologists reported consistent use of thyroid shields, lead glasses, and room shields during fluoroscopically guided interventional procedures, even in more recent time periods.

CONCLUSION

This study provides a detailed historical assessment of fluoroscopically guided interventional procedures performed and radiation safety practices used by radiologic technologists from the 1950s through 2009. Results can be used in conjunction with badge dose data to estimate organ radiation dose for studies of radiation-related health risks in radiologic technologists who have worked with fluoroscopically guided interventional procedures.

ASSESSING THE USEFULNESS OF THE QUASI-IDEAL OBSERVER FOR QUALITY CONTROL IN FLUOROSCOPY

The aim of this work was to evaluate the reliability of the square of the signal-to-noise ratio rate, [Formula: see text], as a precise measurement for quality control test in a digital fluoroscopy system. The quasi-ideal model observer was used to measure [Formula: see text] The dose rate, pulse rate and field of view were varied, and their effect on dose efficiency, defined as [Formula: see text], was evaluated (where [Formula: see text] is the air kerma-area product rate). Measurements were repeated to assess reproducibility. The relative standard deviation in [Formula: see text] over seven consecutive measurements was 5 %. No significant variation in [Formula: see text] was observed across different pulse rates (10-30 pulses s(-1)). The low-dose-rate setting had a superior dose efficiency compared with the medium- and high-dose-rate settings. A smaller field of view resulted in higher dose efficiency.The results show that [Formula: see text] measurements offer the high precision required in quality control constancy tests.

Effect of fluoroscopic X-ray beam spectrum on air-kerma measurement accuracy: implications for establishing correction coefficients on interventional fluoroscopes with KAP meters

The first goal of this study was to investigate the accuracy of the displayed reference plane air kerma (Ka,r) or air kerma-area product (Pk,a) over a broad spectrum of X-ray beam qualities on clinically used interventional fluoroscopes incorporating air kerma-area product meters (KAP meters) to measure X-ray output. The second goal was to investigate the accuracy of a correction coefficient (CC) determined at a single beam quality and applied to the measured Ka,r over a broad spectrum of beam qualities. Eleven state-of-the-art interventional fluoroscopes were evaluated, consisting of eight Siemens Artis zee and Artis Q systems and three Philips Allura FD systems. A separate calibrated 60 cc ionization chamber (external chamber) was used to determine the accuracy of the KAP meter over a broad range of clinically used beam qualities. For typical adult beam qualities, applying a single CC deter-mined at 100 kVp with copper (Cu) in the beam resulted in a deviation of < 5% due to beam quality variation. This result indicates that applying a CC determined using The American Association of Physicists in Medicine Task Group 190 protocol or a similar protocol provides very good accuracy as compared to the allowed ± 35% deviation of the KAP meter in this limited beam quality range. For interventional fluoroscopes dedicated to or routinely used to perform pediatric interventions, using a CC established with a low kVp (~ 55-60 kVp) and large amount of Cu filtration (~ 0.6-0.9 mm) may result in greater accuracy as compared to using the 100 kVp values. KAP meter responses indicate that fluoroscope vendors are likely normalizing or otherwise influencing the KAP meter output data. Although this may provide improved accuracy in some instances, there is the potential for large discrete errors to occur, and these errors may be difficult to identify.

Patient radiation doses in various fluoroscopically guided orthopaedic procedures

All orthopaedic fluoroscopic procedures performed using C-arm guidance were monitored for 1 y. The type of procedure, fluoroscopy time (T), kerma-area product (KAP) values and number of radiographs (F) were recorded. The two most often performed techniques were as follows: intramedullary nailing (IMN) of intertrochanteric/peritrochanteric (IP) fractures (101 cases, 49.3 %) and antergrade IMN of femur or tibia shaft (TS) fractures (28 cases, 13.7 %). For the remaining procedures, none accounted for >5 %, categorised as 'various' (76 cases, 37 %). Large variations in T, KAP and F were observed. For IMN of IP fractures, antergrade IMN of femur and TS fractures and for various procedures, respectively, median values were T--2.1, 2.2 and 0.6 min, KAP--6.3, 6.3 and 0.6 Gy cm(-2) and F--21, 2.2 and 6.7. The patient doses during fluoroscopically guided procedures are relatively low compared with other interventional procedures.

Local patient dose diagnostic reference levels in pediatric interventional cardiology in Chile using age bands and patient weight values

PURPOSE

To present the results of a patient dose evaluation program in pediatric cardiology and propose local diagnostic reference levels (DRLs) for different types of procedure and age range, in addition to suggesting approaches to correlate patient dose values with patient weight. This study was the first conducted in Latin America for pediatric interventional cardiology under the auspices of the International Atomic Energy Agency.

METHODS

Over three years, the following data regarding demographic and patient dose values were collected: age, gender, weight, height, number of cine series, total number of cine frames, fluoroscopy time (FT), and two dosimetric quantities, dose-area product (DAP) and cumulative dose (CD), at the patient entrance reference point. The third quartile values for FT, DAP, CD, number of cine series, and the DAP/body weight ratio were proposed as the set of quantities to use as local DRLs.

RESULTS

Five hundred and seventeen patients were divided into four age groups. Sample sizes by age group were 120 for <1 yr; 213 for 1 to <5 yr; 82 for 5 to <10 yr; and 102 for 10 to <16 yr. The third quartile values obtained for DAP by diagnostic and therapeutic procedures and age range were 1.17 and 1.11 Gy cm2 for <1 yr; 1.74 and 1.90 Gy cm2 for 1 to <5 yr; 2.83 and 3.22 Gy cm2 for 5 to <10 yr; and 7.34 and 8.68 Gy cm2 for 10 to <16 yr, respectively. The third quartile value obtained for the DAP/body weight ratio for the full sample of procedures was 0.17 (Gy cm2/kg) for diagnostic and therapeutic procedures.

CONCLUSIONS

The data presented in this paper are an initial attempt at establishing local DRLs in pediatric interventional cardiology, from a large sample of procedures for the standard age bands used in Europe, complemented with the values of the ratio between DAP and patient weight. This permits a rough estimate of DRLs for different patient weights and the refining of these values for the age bands when there may be large differences in child size. These DRLs were obtained at the largest pediatric hospital in Chile, with an active optimization program, and could be used by other hospitals in the Latin America region to compare their current patient dose values and determine whether corrective action is appropriate.

Value of Examination Under Fluoroscopy for the Assessment of Sacroiliac Joint Dysfunction

BACKGROUND

Pain emanating from the sacroiliac (SI) joint can have variable radiation patterns. Single physical examination tests for SI joint pain are inconsistent with multiple tests increasing both sensitivity and specificity.

OBJECTIVE

To evaluate the use of fluoroscopy in the diagnosis of SI joint pain.

STUDY DESIGN

Prospective double blind comparison study.

SETTING

Pain clinic and radiology setting in urban Veterans Administration (VA) in New Orleans, Louisiana.

METHODS

Twenty-two adult men, patients at a southeastern United States VA interventional pain clinic, presented with unilateral low back pain of more than 2 months' duration. Patients with previous back surgery were excluded from the study. Each patient was given a Gapping test, Patrick (FABERE) test, and Gaenslen test. A second blinded physician placed each patient prone under fluoroscopic guidance, asking each patient to point to the most painful area. Pain was provoked by applying pressure with the heel of the palm in that area to determine the point of maximum tenderness. The area was marked with a radio-opaque object and was placed on the mark with a fluoroscopic imgage. A site within 1 cm of the SI joint was considered as a positive test. This was followed by a diagnostic injection under fluoroscopy with 1 mL 2% lidocaine. A positive result was considered as more than 2 hours of greater than 75% reduction in pain. Then, in 2-3 days this was followed by a therapeutic injection under fluoroscopy with 1 mL 0.5% bupivacaine and 40 mg methylprednisolone.

RESULTS

Each patient was reassessed after 6 weeks. The sensitivity and specificity in addition to the positive and negative predictive values were determined for both the conventional examinations, as well as the examination under fluoroscopy. Finally, a receiver operating characteristic (ROC) curve was constructed to evaluate test performance. The sensitivity and specificity of the fluoroscopic examination were 0.82 and 0.80 respectively; Positive predictive value and negative predictive value were 0.93 and 0.57 respectively. The area under ROC curve was 0.812 which is considered a "good" test; however the area under ROC for the conventional examination were between 0.52-0.58 which is considered "poor to fail".

LIMITATIONS

Variation in anatomy of the SI joint, small sample size.

CONCLUSIONS

Multiple structures of the SI joint complex can result in clinical symptoms of pain. These include intra-articular structures (degenerative arthritis, and inflammatory conditions) as well as extra-articular structures (ligaments, muscles, etc.).

Implications in medical imaging of the new ICRP thresholds for tissue reactions

The International Commission on Radiological Protection (ICRP) statement on tissue reactions, issued by the Commission in April 2011, reviewed epidemiological evidence and suggested that there are some tissue reactions where threshold doses are or may be lower than those previously considered. For the lens of the eye, the threshold is now considered to be 0.5 Gy. The absorbed dose threshold for circulatory disease in the heart and brain may be as low as 0.5 Gy. These values can be reached in some patients during interventional cardiology or neuroradiology procedures. They may also be of concern for repeated computed tomography examinations of the head. The new thresholds should be considered in optimisation strategies for clinical procedures, especially in patients likely to require repeated interventions. The new dose thresholds also affect occupational protection for operators and staff. Some operators do not protect their eyes or their brain adequately. After several years of work without proper protection, the absorbed doses to the lens of the eye and the brain of staff can exceed 0.5 Gy. More research is needed to understand the biological effects of cumulative incident air kerma and the instantaneous air kerma rates currently used in medical imaging. The new thresholds, and the need for specific occupational dosimetry related to lens doses, should be considered in radiation protection programmes, and should be included in the education and training of professionals involved in fluoroscopy guided procedures and computed tomography.

Performance of mobile digital X-ray fluoroscopy using a novel flat panel detector for intraoperative use

BACKGROUND

Technologies employing digital X-ray devices are developed for mobile settings.

OBJECTIVE

To develop a mobile digital X-ray fluoroscopy (MDF) for intraoperative guidance, using a novel flat panel detector to focus on diagnostics in outpatient clinics, operating and emergency rooms.

METHODS

An MDF for small-scale field diagnostics was configured using an X-ray source and a novel flat panel detector. The imager enabled frame rates reaching 30 fps in full resolution fluoroscopy with maximal running time of 5 minutes. Signal-to-noise (SNR), contrast-to-noise (CNR), and spatial resolution were analyzed. Stray radiation, exposure radiation dose, and effective absorption dose were measured for patients.

RESULTS

The system was suitable for small-scale field diagnostics. SNR and CNR were 62.4 and 72.0. Performance at 10% of MTF was 9.6 lp/mm (53 μ m) in the no binned mode. Stray radiation at 100 cm and 150 cm from the source was below 0.2 μ Gy and 0.1 μ Gy. Exposure radiation in radiography and fluoroscopy (5 min) was 10.2 μ Gy and 82.6 mGy. The effective doses during 5-min-long fluoroscopy were 0.26 mSv (wrist), 0.28 mSv (elbow), 0.29 mSv (ankle), and 0.31 mSv (knee).

CONCLUSIONS

The proposed MDF is suitable for imaging in operating rooms.

Use of an anatomical scalar to control for sex-based size differences in measures of hyoid excursion during swallowing

PURPOSE

Traditional methods for measuring hyoid excursion from dynamic videofluoroscopy recordings involve calculating changes in position in absolute units (mm). This method shows a high degree of variability across studies but agreement that greater hyoid excursion occurs in men than in women. Given that men are typically taller than women, the authors hypothesized that controlling for participant size might neutralize apparent sex-based differences in hyoid excursion.

METHOD

Hyoid excursion in 20 young (<45) healthy volunteers (10 male), stratified by height, was measured in a tightly controlled videofluoroscopic protocol.

RESULTS

The study identified an anatomical scalar (C2-C4 length), visible on the videofluoroscopic image, correlated with participant height. This scalar differed significantly between men and women. By incorporating the anatomical scalar as a continuous covariate in repeated measures mixed-model analyses of variance of hyoid excursion, apparent sex-based differences were neutralized. Transforming measures of hyoid excursion into anatomically scaled units achieved the same result, reducing variation attributable to sex-based differences in participant size.

CONCLUSIONS

Hyoid excursion during swallowing is dependent on a person's size. If measurements do not control for this source of variation, apparent sex differences in hyoid excursion are seen.

[Analysis of radiation exposure to medical staff and patients during ERCP in Uruguay]

BACKGROUND

The ERCP procedure requires the use of fluoroscopy with the subsequent exposure to ionizing radiation. The doses received by patients, physicians and assistants in the endoscopy have never been recorded in our area. This analysis describes the findings of the MIRED_Uy study (measuring radiation in digestive endoscopy in Uruguay). Objective. To determine radiation exposure received by patients, physicians and assistants during ERCP.

METHODS

Data were collected from 33 procedures conducted by four endoscopists, supported by endoscopy assistants. All staff took basic radiation-protection measures. The magnitudes measured were the kerma area product (KAP) for the patient and the effective dose (E) and the equivalent doses in hand (HM) and lens of the eyes (HC) for the operators.

RESULTS

Mean value for PKA was 24 Gy.cm2 (range: 0.04-71) equivalent to 312 chest x-rays. The mean fluoroscopy time was 2.3 minutes (range: 0.45 a 5.70 minutes). The E mean per procedure was 3.69, 5.14 y 3.69 muSv, for physician, first and second assistant respectively. The dose in hand for the physician was 19.4 muSv and the dose in lens was 7.94 muSv.

CONCLUSIONS

The first results of measuring ERCP radiation doses in Uruguay are presented These procedures expose the patient and staff to measurable radiation doses, which should be taken into account to minimize their risks.

Robust fluoroscopic tracking of fiducial markers: exploiting the spatial constraints

Two new fluoroscopic fiducial tracking methods that exploit the spatial relationship among the multiple implanted fiducial to achieve fast, accurate and robust tracking are proposed in this paper. The spatial relationship between multiple implanted markers are modeled as Gaussian distributions of their pairwise distances over time. The means and standard deviations of these distances are learned from training sequences, and pairwise distances that deviate from these learned distributions are assigned a low spatial matching score. The spatial constraints are incorporated in two different algorithms: a stochastic tracking method and a detection based method. In the stochastic method, hypotheses of the 'true' fiducial position are sampled from a pre-trained respiration motion model. Each hypothesis is assigned an importance value based on image matching score and spatial matching score. Learning the parameters of the motion model is needed in addition to learning the distribution parameters of the pairwise distances in the proposed stochastic tracking approach. In the detection based method, a set of possible marker locations are identified by using a template matching based fiducial detector. The best location is obtained by optimizing the image matching score and spatial matching score through non-serial dynamic programming. In this detection based approach, there is no need to learn the respiration motion model. The two proposed algorithms are compared with a recent work using a multiple hypothesis tracking (MHT) algorithm which is denoted by MHT, Tang et al (2007 Phys. Med. Biol. 52 4081-98). Phantom experiments were performed using fluoroscopic videos captured with known motion relative to an anthropomorphic phantom. The patient experiments were performed using a retrospective study of 16 fluoroscopic videos of liver cancer patients with implanted fiducials. For the motion phantom data sets, the detection based approach has the smallest tracking error (μerr: 0.78-1.74 mm, σerr: 0.39-1.16 mm) for the images taken at low exposure (50 mAs). At higher exposure (500 mAs), the stochastic method gave the best performance (μerr: ∼0.39 mm, σerr: ∼0.27 mm). In contrast, the tracker (MHT) that does not model the spatial constraints only performs well when there is no occluded fiducial. With the RANDO phantom data, both of our proposed methods performed well and have the mean tracking errors around ∼1.8 mm with the standard deviations ∼0.93 mm at 100 mAs and ∼0.91 mm with 0.88 mm standard deviation at 500 mAs. The MHT tracker has the largest tracking errors with mean ∼4.8 mm) and standard deviation ∼2.4 mm in both sessions with the Rondo phantom data. On the patient data sets, the detection based method gave the smallest error (μerr: 0.39 mm, σerr: ∼0.19 mm). The stochastic method performed well (μerr: ∼0.58 mm, σerr: ∼0.39 mm) when the patient breathed consistently, the accuracy dropped to (μerr: ∼1.55 mm) when the patient breathed differently across sessions.

Protective eyewear selection for interventional fluoroscopy

Three protective eyewear models were evaluated to determine effectiveness in reducing radiation dose to a fluoroscopist's eyes. The performance of the protective eyewear was measured using radiation dosimeters in a fluoroscopy suite. An Eyewear Protection Factor was determined for each model in each of three exposure orientations. The protection was strongly influenced by the location of the radiation source. When the source was in front of the fluoroscopist, the lead equivalence was important. When the source was to the side of the fluoroscopist, the cross section of the side shield had a significant influence on protection. Protective eyewear selection needs to include consideration of job task and head orientation to the radiation source as well as the possibility that face shape and eyewear fit may also impact the radiation dose to the eye.

Practical application of suspension criteria scenarios in general radiography, computed radiography,digital radiography and fluoroscopy

Radiological equipment must be assessed against criteria for acceptability to ensure that it meets the minimum standards for patient safety. This assessment is typically led by a medical physicist with input from radiology staff and the equipment supplier. Equipment that does not meet the criteria requires action and may be suspended from clinical use. European Commission report RP 91 will be revised and replaced as RP 162. It has been drawn up to aid medical physicists with the assessment process and provide guidance on suspension levels. This paper details several cases where the criteria in the proposed RP 162 were applied in general radiography, computed radiography, digital radiography and fluoroscopy. The factors considered by the medical physicist and the outcome of each case are presented. The proposed RP 162 report improves on its predecessor and provides a robust set of criteria for ensuring that patient safety within the EU medical exposures framework is optimised.

Patient radiation dose management in the follow-up of potential skin injuries in neuroradiology

BACKGROUND AND PURPOSE

Radiation exposure from neurointerventional procedures can be substantial, with risk of radiation injuries. We present the results of a follow-up program applied to potential skin injuries in interventional neuroradiology based on North American and European guidelines.

MATERIALS AND METHODS

The following guidelines approved in 2009 by SIR and CIRSE have been used over the last 2 years to identify patients with potential skin injuries requiring clinical follow-up: peak skin dose >3 Gy, air kerma at the patient entrance reference point >5 Gy, kerma area product >500 Gy · cm(2), or fluoroscopy time >60 minutes.

RESULTS

A total of 708 procedures (325 in 2009 and 383 in 2010) were included in the study. After analyzing each dose report, 19 patients (5.9%) were included in a follow-up program for potential skin injuries in 2009, while in 2010, after introducing several optimizing actions and refining the selection criteria, only 4 patients (1.0%) needed follow-up. Over the last 2 years, only 3 patients required referral to a dermatology service.

CONCLUSIONS

The application of the guidelines to patient radiation dose management helped standardize the selection criteria for including patients in the clinical follow-up program of potential skin radiation injuries. The peak skin dose resulted in the most relevant parameter. The refinement of selection criteria and the introduction of a low-dose protocol in the x-ray system, combined with a training program focused on radiation protection, reduced the number of patients requiring clinical follow-up.

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.

ICRP Publication 117. Radiological protection in fluoroscopically guided procedures performed outside the imaging department

An increasing number of medical specialists are using fluoroscopy outside imaging departments, but there has been general neglect of radiological protection coverage of fluoroscopy machines used outside imaging departments. Lack of radiological protection training of those working with fluoroscopy outside imaging departments can increase the radiation risk to workers and patients. Procedures such as endovascular aneurysm repair, renal angioplasty, iliac angioplasty, ureteric stent placement, therapeutic endoscopic retrograde cholangio-pancreatography,and bile duct stenting and drainage have the potential to impart skin doses exceeding Gy. Although tissue reactions among patients and workers from fluoroscopy procedures have, to date, only been reported in interventional radiology and cardiology,the level of fluoroscopy use outside imaging departments creates potential for such injuries.A brief account of the health effects of ionising radiation and protection principles is presented in Section 2. Section 3 deals with general aspects of the protection of workers and patients that are common to all, whereas specific aspects are covered in Section 4 for vascular surgery, urology, orthopaedic surgery, obstetrics and gynaecology,gastroenterology and hepatobiliary system, and anaesthetics and pain management.Although sentinel lymph node biopsy involves the use of radio-isotopic methods rather than fluoroscopy, performance of this procedure in operating theatres is covered in this report as it is unlikely that this topic will be addressed in another ICRP publication in coming years. Information on radiation dose levels to patients and workers, and dose management is presented for each speciality.

The utility of pitch elevation in the evaluation of oropharyngeal Dysphagia: preliminary findings

PURPOSE

To evaluate the utility of a pitch elevation task in the assessment of oropharyngeal dysphagia.

METHOD

This study was a pilot prospective cohort study including 40 consecutive patients (16 male and 24 female) who were referred by their physician for a swallowing evaluation. Patients were evaluated with a noninstrumental clinical examination and a videofluoroscopic swallow study, and participated in a pitch elevation task during videofluoroscopic image acquisition. Relationships between pitch elevation measurements (acoustic and perceptual) and swallow parameters (penetration/aspiration and residue) were investigated.

RESULTS

Results of this pilot study revealed that both maximum fundamental frequency (F(0)) and perceptual evaluation of pitch elevation independently significantly predicted Penetration-Aspiration Scale scores for thin liquid swallows (p = .01 and .03, respectively). Vocal range (average pitch to falsetto) was not sensitive in predicting likelihood of oropharyngeal dysphagia.

CONCLUSIONS

Findings indicate that reduced pitch elevation can be indicative of reduced airway protection and swallowing impairment in some dysphagia patients and may be a useful supplement to dysphagia screening and diagnosis. Further investigation is warranted to determine the optimal utility of this procedure for different diagnostic categories of patients.

Accuracy of freehand fluoroscopy-guided placement of C1 lateral mass and C2 isthmic screws in atlanto-axial instability

BACKGROUND

The C1 lateral mass and C2 isthmic stabilization, as introduced by Goel and Laheri and by Harms and Melcher, is a well-known fixation technique. We present the clinical and radiographic results with freehand fluoroscopy guided C1 lateral mass and C2 isthmic fixation in a consecutive series of 28 patients, evaluating the accuracy of screw placement.

METHODS

Twenty-eight consecutive patients suffering from post-traumatic and other C1-C2 instability were operated on between 2001 and 2010. Indications for surgery were: trauma (n = 21 cases), os odontoideum (n = 1), cranio-verterbal malformation (n = 1), and arthritis (n = 3) and idiopathic instability (n = 2). C1 lateral mass and C2 isthmic screws were placed according to the usual anatomical landmarks with lateral fluoroscopy guidance. All patients underwent a postoperative CT scan. The extent of cortical lateral or medial breach was determined and classified as follows: no breach (grade A), 0-2 mm (grade B), 2-4 mm (grade C), 4-6 mm (grade D), more than 6 mm (grade E). Grade A and B screws were considered well positioned.

RESULTS

A total of 56 C1 lateral mass and 55 C2 isthmic screws were placed. Accuracy of screw placement was as follows: 107 grade A (96.4%), four grade B (3.6%), and no grade C, D or E. Clinical and radiological follow-up showed improvement in symptoms (mainly pain) and stability of the implants at the end of the follow-up.

CONCLUSIONS

Freehand fluoroscopy-guided insertion of C1 lateral mass and C2 isthmic screws can be safely and effectively performed.

[Radiation protection of patients in interventional radiology]

The purpose of this article is to provide radiologists with key elements of radiation protection for interventional radiology patients. The following points will be discussed: standards of the fluoroscopy units, dedicated dosimetry, risks (especially cutaneous) and means to reduce them, optimization of interventional radiology dose protocols, and national and international regulations. Appropriateness criteria in interventional radiology are national guidelines that should be implemented.

Nationwide surveys of chest, abdomen, lumbosacral spine radiography, and upper gastrointestinal fluoroscopy: a summary of findings

This paper reports findings from Nationwide Evaluation of X-ray Trends surveys conducted in 2001, 2002, and 2003 of clinical facilities that perform routine radiographic examinations of the adult chest, abdomen, lumbosacral spine, and upper gastrointestinal fluoroscopic examinations. Randomly identified clinical facilities were surveyed in approximately 40 participating states. For the surveyed radiographic exams, additional facilities that use computed radiography or digital radiography were surveyed to ensure adequate sample sizes for determining comparative statistics. State radiation control personnel performed site visits and collected data on patient exposure, radiographic/fluoroscopic technique factors, image quality, and quality-control and quality-assurance practices. Results of the NEXT surveys are compared with those of previous surveys conducted in 1964 and 1970 by the U.S. Public Health Service and the Food and Drug Administration. An estimated 155 million routine adult chest exams were performed in 2001. Average patient entrance skin air kerma from chest radiography at facilities using digital-based imaging modalities was found to be significantly higher (p < 0.001), but not so for routine abdomen or lumbosacral spine radiography. Digital-based imaging showed a substantial reduction in patient exposure for the radiographic portion of the routine upper gastrointestinal fluoroscopy exam. Long-term trends in surveyed diagnostic examinations show that average patient exposures are at their lowest levels. Of concern is the observation that a substantial fraction of surveyed non-hospital sites indicated they do not regularly have a medical physics survey conducted on their radiographic equipment. These facilities are likely unaware of the radiation doses they administer to their patients.

Technical advances of interventional fluoroscopy and flat panel image receptor

In the past decade, various radiation reducing devices and control circuits have been implemented on fluoroscopic imaging equipment. Because of the potential for lengthy fluoroscopic procedures in interventional cardiovascular angiography, these devices and control circuits have been developed for the cardiac catheterization laboratories and interventional angiography suites. Additionally, fluoroscopic systems equipped with image intensifiers have benefited from technological advances in x-ray tube, x-ray generator, and spectral shaping filter technologies. The high heat capacity x-ray tube, the medium frequency inverter generator with high performance switching capability, and the patient dose reduction spectral shaping filter had already been implemented on the image intensified fluoroscopy systems. These three underlying technologies together with the automatic dose rate and image quality (ADRIQ) control logic allow patients undergoing cardiovascular angiography procedures to benefit from "lower patient dose" with "high image quality." While photoconductor (or phosphor plate) x-ray detectors and signal capture thin film transistor (TFT) and charge coupled device (CCD) arrays are analog in nature, the advent of the flat panel image receptor allowed for fluoroscopy procedures to become more streamlined. With the analog-to-digital converter built into the data lines, the flat panel image receptor appears to become a digital device. While the transition from image intensified fluoroscopy systems to flat panel image receptor fluoroscopy systems is part of the on-going "digitization of imaging," the value of a flat panel image receptor may have to be evaluated with respect to patient dose, image quality, and clinical application capabilities. The advantage of flat panel image receptors has yet to be fully explored. For instance, the flat panel image receptor has its disadvantages as compared to the image intensifiers; the cost of the equipment is probably the most obvious. On the other hand, due to its wide dynamic range and linearity, lowering of patient dose beyond current practice could be achieved through the calibration process of the flat panel input dose rate being set to, for example, one half or less of current values. In this article various radiation saving devices and control circuits are briefly described. This includes various types of fluoroscopic systems designed to strive for reduction of patient exposure with the application of spectral shaping filters. The main thrust is to understand the ADRIQ control logic, through equipment testing, as it relates to clinical applications, and to show how this ADRIQ control logic "ties" those three technological advancements together to provide low radiation dose to the patient with high quality fluoroscopic images. Finally, rotational angiography with computed tomography (CT) and three dimensional (3-D) images utilizing flat panel technology will be reviewed as they pertain to diagnostic imaging in cardiovascular disease.

Quality control measurements for fluoroscopy systems in eight countries participating in the SENTINEL EU coordination action

Quality control (QC) is becoming increasingly important in relation to the introduction of digital medical imaging systems using X rays. It was, therefore, decided to organise and perform a trial on image quality and physical measurements. The SENTINEL toolkit for QC measurements of fluoroscopy systems containing equipment and instructions for their use in the assessment of dose and image quality circulated among participants in the trial. The participants reported on their results. In the present contribution, the impact of the trial on the selected protocols is presented. The Medical Physics and Bioengineering protocol appeared to be useful for QC, and also for digital systems. The protocol needs an additional section, or an addition to each section, to state compliance with the requirements. The circular cross-sections of the Leeds test objects need adaptation for rectangular flat panel detector (FPD) systems. Only one participant was able to perform the monitor test using MoniQA. This is due to the fact that assistance is required from the suppliers of the X-ray systems. This problem needs to be solved to apply MoniQA in practice.

A pilot experience launching a national dose protocol for vascular and interventional radiology

The design of a national dose protocol for interventional radiology has been one of the tasks during the European SENTINEL Coordination Action. The present paper describes the pilot experience carried out in cooperation with the Spanish Society on Vascular and Interventional Radiology (SERVEI). A prospective sample of procedures was initially agreed. A common quality control of the X-ray systems was carried out, including calibration of the air kerma area product (KAP) meters. Occupational doses of the radiologists involved in the survey were also included in the survey. A total of 10 Spanish hospitals with interventional X-ray units were involved. Six hundred and sixty-four patient dose data were collected from 397 diagnostic and 267 therapeutic procedures. Occupational doses were evaluated in a sample of 635 values. The obtained KAP median/mean values (Gy.cm2) for the gathered procedures were: biliary drainage (30.6/68.9), fistulography (4.5/9.8), lower limb arteriography (52.2/60.7), hepatic chemoembolisation (175.8/218.3), iliac stent (45.9/73.2) and renal arteriography (39.1/59.8). Occupational doses (mean monthly values, in mSv) were 1.9 (over apron); 0.3 (under apron) and 4.5 (on hands). With this National experience, a protocol was agreed among the SENTINEL partners to conduct future similar surveys in other European countries.

Acceptance testing and QA of interventional cardiology systems

Interventional cardiology (IC) is a rapidly growing field of medical specialisation. Such procedures are complex and may subject patients and operators to higher levels of risk than those encountered in general radiology. Acceptance testing and quality assurance (QA) of radiological equipment, including IC equipment, is a requirement of the EU Medical Exposures Directive (MED) (97/43/EURATOM). In addition, the MED identifies interventional radiology as an area of special concern. This study presents the results of a survey of 17 IC systems (including several flat panel detector systems) in Irish hospitals. The results of the survey indicate large differences in patient doses between manufacturers for equivalent levels of measured image quality. In addition, all systems were found to have failed one or more acceptance tests, with 60% of systems demonstrating significant problems at acceptance testing. The results of the survey demonstrate the importance of acceptance testing and QA in IC. The results also provide baseline data, which may be used in the development of future QA guidelines.

Diagnostic reference levels in angiography and interventional radiology: a Belgian multi-centre study

The purpose of this study was to determine diagnostic reference levels (DRLs) for common angiographic and interventional procedures in Belgium. Dose Area Product (DAP) measurements were performed on 21 systems, (13 angiography and 4 vascular surgery centres). Type of procedure, total DAP, patient weight and height were collected on a daily basis during 1 y. The 75th percentile of the distribution of DAP values was defined as DRL. Preliminary DRLs were calculated for the three most frequent procedures for the whole population, for a weight class of patients (65-80 kg) and normalised to the standard size patient. Among them, the DRL for angiography of the lower limbs (30% of the procedures) from the whole population was 74.6 and 63.2 Gycm2 for the size corrected. The mean DAP values of each room was then compared to these DRLs.

Acceptance testing of fluoroscopy systems used for interventional purposes

This study presents the results of acceptance testing on 18 interventional fluoroscopy systems in Ireland. Acceptance testing and routine quality assurance (QA) of X-ray systems are the requirements of the EU Medical Exposures Directive (MED) and these requirements were subsequently implemented into Irish legislation. The MED states that special consideration should be given to the QA and dose assessment of high dose procedures such as interventional fluoroscopy. Owing to the advances in fluoroscopy technology, it has been found that comprehensive testing of interventional systems proves challenging in a busy hospital environment. A number of recurrent problems have been identified and are presented.

Level of patient and operator dose in the largest cardiac centre in Greece

The objective of this study was to investigate the patient and staff doses in the most frequent interventional cardiology (IC) procedures performed in Onassio, the largest Cardiac Centre in Greece. Data were collected from three digital X-ray systems for 212 coronary angiographies, 203 percutaneous transluminal coronary angioplasties (PTCA) and 134 various electrophysiological studies. Patient skin dose was measured using suitably calibrated slow radiotherapy films and cardiologist dose using suitably calibrated thermoluminescent dosemeters placed on left arm, hand and foot. Patient median dose area product (DAP) (all examinations) ranged between 6.7 and 83.5 Gy cm2. Patient median skin dose in PTCA was 799 mGy (320-1660 mGy) and in RF ablation 160 mGy (35-1920 mGy). Median arm, hand and foot dose to the cardiologist were 12.6, 27 and 13 microSv, respectively, per procedure. The great range of radiation doses received by both patients and operators confirms the need for continuous monitoring of all IC techniques.

A large-scale multicentre study in Belgium of dose area product values and effective doses in interventional cardiology using contemporary X-ray equipment

In this paper, a large-scale multicentre patient dose study performed in eight Belgian interventional cardiology departments is presented. Effective dose (E) was calculated based on a detailed dose-area product (DAP)-registration during each procedure and by using conversion coefficients generated by the Monte Carlo-based computer program PCXMC. Conversion coefficients were found to be 0.177 mSv Gycm(-2) for systems that do not use any additional copper filtration in cineradiography and 0.207 mSv Gycm(-2) for systems that use additional copper filtration in cineradiography. Mean E values of 9.6 and 15.3 mSv for diagnostic and therapeutic procedures, respectively, were obtained. DAP distributions were investigated in order to derive dose reference levels: 71 and 106 Gycm2 for diagnostic and therapeutic procedures, respectively, are proposed. Significant differences were observed in DAP distributions taking into account whether additional copper filtration was used in the cineradiography mode. Apart from the skin, the organs most at risk are lungs and heart. The probability of fatal cancer for the studied population amounted to 1.1x10(-4) and 2.1x10(-4) for diagnostic and therapeutic procedures, respectively, for the age distribution of the patients considered in this multicentre study.

Use of the mini C-arm for wrist fractures--establishing a diagnostic reference level

The establishment of diagnostic reference levels (DRLs) for all typical radiological examinations became mandatory following the implementation of the Ionising Radiations (Medical Exposure) Regulations Act 2000. At present, there are no national dosage guidelines in the UK regarding use of fluoroscopy in orthopaedic trauma. The increasing popularity of the mini C-arm image intensifier amongst surgeons has led to concerns regarding use of ionizing radiation by personnel who have not been trained in radiation protection. It is therefore essential to have formal protocols for use of the mini C-arm to comply with the law and to maintain safe clinical practice. It is attempted to provide dose data for wrist fracture manipulations that may be used as a basis for setting a DRL for this procedure. Screening times were recorded for 80 wrist manipulations in a fracture clinic setting using a mini C-arm image intensifier. A DRL was set using the third quartile value for screening time. The median screening time for wrist fractures was 20 s with a range from 1 to 177 s. The third quartile value for screening time was 34 s. This value can be used as a provisional DRL for wrist fracture manipulations. The DRL is a quantitative guide for the optimisation of radiological protection. IR(ME)R 2000 states that if it is consistently exceeded by an individual operator or a piece of equipment, investigation and remedial action must be taken. We recommend that trauma units establish their own local DRLs for common procedures as made mandatory by legislation.

Image quality evaluation and patient dose assessment of medical fluoroscopic X-ray systems: a national study

This study presents the results from a survey conducted by the Greek Atomic Energy Commission (GAEC), during the period 1998-2003, in 530 public and private owned fluoroscopic X-ray systems in Greece. Certain operational parameters for conventional and remote control systems were assessed, according to a quality control protocol developed by GAEC on the basis of the current literature. Public (91.5%) and private (81.5%) owned fluoroscopic units exhibit high-contrast resolution values over 1 lp mm(-1). Moreover, 88.5 and 87.1% of the fluoroscopic units installed in the public and private sector, respectively, present Maximum Patient Entrance Kerma Rate values lower than 100 mGy min(-1). Additionally, 68.3% of the units assessed were found to perform within the acceptance limits. Finally, the third quartile of the Entrance Surface Dose Rate distribution was estimated according to the Dose Reference Level definition and found equal to 35 mGy min(-1).

Radiation dose measurement and risk estimation for paediatric patients undergoing micturating cystourethrography

Micturating cystourethrography (MCU) is considered to be the gold-standard method used to detect and grade vesicoureteric reflux (VUR) and show urethral and bladder abnormalities. It accounts for 30-50% of all fluoroscopic examinations in children. Therefore, it is crucial to define and optimize the radiation dose received by a child during MCU examination, taking into account that children have a higher risk of developing radiation-induced cancer than adults. This study aims to quantify and evaluate, by means of thermoluminescence dosimetry (TLD), the radiation dose to the newborn and paediatric populations undergoing MCU using fluoroscopic imaging. Evaluation of entrance surface dose (ESD), organ and surface dose to specific radiosensitive organs was carried out. Furthermore, the surface dose to the co-patient, i.e. individuals helping in the support, care and comfort of the children during the examination, was evaluated in order to estimate the level of risk. 52 patients with mean age of 0.36 years who had undergone MCU using digital fluoroscopy were studied. ESD, surface doses to thyroid, testes/ovaries and co-patients were measured with TLDs. MCU with digital equipment and fluoroscopy-captured image technique can reduce the radiation dose by approximately 50% while still obtaining the necessary diagnostic information. Radiographic exposures were made in cases of the presence of reflux or of the difficulty in evaluating a finding. The radiation surface doses to the thyroid and testes are relatively low, whereas the radiation dose to the co-patient is negligible. The risks associated with MCU for patients and co-patients are negligible. The results of this study provide baseline data to establish reference dose levels for MCU examination in very young patients.