Radiation exposure to patients during interventional procedures in 20 countries: initial IAEA project results. AJR Am J Roentgenol. 2009;193:559-569. [PMID: 19620457 DOI: 10.2214/ajr.08.2115]

Clinical diagnostic reference levels in neuroradiology based on clinical indication

This study focuses on patient radiation exposure in interventional neuroradiology (INR) procedures, a field that has advanced significantly since its inception in the 1980s. INR employs minimally invasive techniques to treat complex cerebrovascular diseases in the head, neck, and spine. The study establishes diagnostic reference levels (DRLs) for three clinical indications (CIs): stroke (S), brain aneurysms (ANs), and brain arteriovenous malformation (AVM). Data from 209 adult patients were analyzed, and DRLs were determined in terms of various dosimetric and technical quantities. For stroke, the established DRLs median values were found to be 78 Gy cm2, 378 mGy, 118 mGy, 12 min, 442 images, and 15 runs. Similarly, DRLs for brain AN are 85 Gy cm2, 611 mGy, 95.5 mGy, 19.5, 717 images, and 26 runs. For brain AVM, the DRL's are 180 Gy cm2, 1144 mGy, 537 mGy, 36 min, 1375 images, and 31 runs. Notably, this study is unique in reporting DRLs for specific CIs within INR procedures, providing valuable insights for optimizing patient safety and radiation exposure management.

Understanding the factors that influence CT utilization for mild traumatic brain injury in a low resource setting - a qualitative study using the Theoretical Domains Framework

Introduction

In low resource settings (LRS), utilization of Computed Tomography scan (CTS) for mild traumatic brain injuries (mTBIs) presents unique challenges and considerations given the limited infrastructure, financial resources, and trained personnel. The Theoretical Domains Framework (TDF) offers a comprehensive theoretical lens to explore factors influencing the decision-making to order CTS for mTBI by imaging referrers (IRs).

Objectives

The primary objective was to explore IRs' beliefs about factors influencing CT utilization in mTBIs using TDF in Uganda.Differences in the factors influencing CTS ordering behavior across specialties, levels of experience, and hospital category were also explored.

Materials and Methods

In-depth semi-structured interviews guided by TDF were conducted among purposively selected IRs from 6 tertiary public and private hospitals with functional CTS services. A thematic analysis was performed with codes and emerging themes developed based on the TDF.

Results

Eleven IRs including medical officers, non-neurosurgeon specialists and neurosurgeons aged on average 42 years (SD+/-12.3 years) participated.Identified factors within skills domain involved IRs' clinical assessment and decision-making abilities, while beliefs about capabilities and consequences encompassed their confidence in diagnostic abilities and perceptions of CTS risks and benefits. The environmental context and resources domain addressed the availability of CT scanners and financial constraints. The knowledge domain elicited IRs' understanding of clinical guidelines and evidence-based practices while social influences considered peer influence and institutional culture. For memory, attention & decision processes domain, IRs adherence to guidelines and intentions to order CT scans were cited.

Conclusion

Using TDF, IRs identified several factors believed to influence decision making to order CTS in mTBI in a LRS. The findings can inform stakeholders to develop targeted strategies and evidence-based interventions to optimize CT utilization in mTBI such as; educational programs, workflow modifications, decision support tools, and infrastructure improvements, among others.

An audit of patient radiation doses during interventional cardiology procedures in Uttarakhand, India, and establishment of local diagnostic reference levels

The objective of this study was to investigate patient radiation doses by a dose audit of three common interventional cardiology (IC) procedures: coronary angiography (CA), percutaneous transluminal coronary angioplasty (PTCA) and CA-PTCA procedures performed in IC centres in the Uttarakhand state of India, for the establishment of local diagnostic reference levels (DRLs) and the estimation of average effective dose (Eav) for these procedures. For each procedure, the values of kerma-area product (PKA), reference air kerma (Ka,r), fluoroscopy time (FT) and the number of cine images were recorded from 1233 CA, 458 PTCA and 736 CA-PTCA procedures performed over a 12-month period at 13 IC centres of the state. From the recorded dose data, 0.6%, 1.53% and 7.9% patients were identified to have exceeded the PKA trigger level of 500 Gy cm2 for possible skin injury for CA, PTCA and CA-PTCA procedures, respectively. The 3rd quartile of the distribution of the recorded PKA values for each type of procedure was calculated to estimate local DRL values. The estimated values of DRLs and Eav were 37, 153 and 224 Gy cm2, and 6.72, 23.97 and 34.79 mSv for CA, PTCA and CA-PTCA procedures, respectively. For about 77% of the surveyed centres, the recorded patient doses were in agreement with the international standards. The local DRLs proposed in this study may be used to achieve patient dose optimization during IC procedures and the obtained patient dose data may also be archived into national dose database for the establishment of national DRLs.

Cumulative Effective Dose During Fluoroscopically Guided Interventions (FGI): Analysis of More Than 5000 FGIs in a Single European Center

BACKGROUND

The number of fluoroscopically guided interventions (FGI) has increased significantly over time. However, little attention has been paid to possible stochastic radiation effects. The aim of this retrospective study was to investigate the number of patients who received cumulative effective doses over 100 mSv during FGI procedures.

MATERIAL AND METHODS

Five thousand five hundred and fifty four classified FGI procedures were included. Radiation dose data, retrieved from an in-house-dose-management system, was analysed. Effective doses and cumulative effective doses (CED) were calculated. Patients who received a CED > 100 mSv were identified. Radiology reports, patient age, imaging and clinical data of these patients were used to identify reasons for CED ≥ 100 mSv.

RESULTS

One Hundred and thirty two (41.1% female) of 3981 patients received a CED > 100 mSy, with a mean CED of 173.5 ± 84.5 mSv. Mean age at first intervention was 66.1 ± 11.7 years. 81 (61.4%) of 132 were older than 64 years, one patient was < 30 years. 110 patients received ≥ 100 mSv within one year (83.4%), through FGIs: EVAR, pelvic/mesenteric interventions (stent or embolization), hepatic interventions (chemoembolization, TIPSS), embolization of cerebral aneurysms or arterio-venous-malformations.

CONCLUSIONS

Substantial CED may occur in a small but not ignorable fraction of patients (~ 3%) undergoing FGIs. Approximately 2/3rd of patients may most likely not encounter radiation-related stochastic effects due to life-threatening diseases and age at first treatment > 65 years but 1/3rd may. Patients undergoing more than one FGI (77%) carry a higher risk of accumulating effective doses > 100 mSv. Remarkably, 23% received a mean CED 162.2 ± 72.3 mSv in a single procedure.

DIAGNOSTIC REFERENCE LEVELS AND COMPLEXITY INDICES IN INTERVENTIONAL RADIOLOGY

The establishment of typical diagnostic reference levels (DRLs) values according to the complexity indices (CIs) for hepatic chemoembolisation (HC), iliac stent placement (ISP) and femoropopliteal revascularisation (FR) is reported in this study. To estimate patients' stochastic effects, effective dose was calculated through dose area product (DAP) values of this study and E/DAP conversion factors derived from the literature. Data for DAP, Reference Air Kerma (Ka,r) and fluoroscopy time (FT) were collected for 218 patients and CIs were assigned to each procedure to extract DRLs. To estimate effective dose, conversion factors and DAP values were used for seven IR procedures. DRL values for DAP were 141, 130 and 28 Gy*cm2 for HC, ISP, and FR, respectively. The corresponding DRL values for Ka,r were 634.6, 300.1 and 112.0 mGy, and for FT were 15.3, 12.4 and 17.9 min, respectively. CIs in interventional radiology are a useful tool for the optimisation of DRLs since they contribute to patient's doses.

The Effect of Pre-Operative Verbal Confirmation for Interventional Radiology Physicians on Their Use of Personal Dosimeters and Personal Protective Equipment

Interventional radiology (IR) physicians must be equipped with personal passive dosimeters and personal protective equipment (PPE); however, they are inconsistently used. Therefore, we aimed to explore practical measures to increase PPE usage and ascertain whether these measures could lead to an actual decrease in exposure doses to IR physicians. Dosimeters and PPE were visually inspected. Then, a pre-operative briefing was conducted as a direct intervention, and the use of dosimeters and PPE was verbally confirmed. Finally, the intervention effect was verified by measuring the use rates and individual exposure doses. Because of the intervention, the use rate markedly improved and was almost 100%. However, both the effective dose rate (effective dose/fluoroscopy time) and the lens equivalent dose rate (lens equivalent dose/fluoroscopy time) showed that the intervention led to a statistically significant increase in exposure (effective dose rate: p = 0.033; lens equivalent dose rate: p = 0.003). In conclusion, the proper use of dosimeters and PPE raised the radiation exposure values for IR physicians immediately after the intervention, which was hypothesized to be due to the inclusion of exposure overlooked to date and the changes in the dosimeter management method from a single- to a double-dosimeter approach.

DIAGNOSTIC REFERENCE LEVELS BASED ON PATIENT BODY MASS INDEX FOR SELECT INTERVENTIONAL PROCEDURES IN MINAS GERAIS/BRAZIL

This work establishes local diagnostic reference levels (DRLs) in interventional radiology based on adult patient body mass index (BMI). The monitoring was carried out from 23 institutions and patient data from 3015 procedures were collected, being 907 Catheterism (CAT), 921 Percutaneous transluminal coronary angioplasty (PTCA) and 1187 CAT/PTCA and 6 BMI ranges were taken, going from under 18 up to 40 kg·m-2. It is presented that 18 initial DRL values to be used in the county of Minas Gerais. The overall 75th kerma-area product (KAP), commonly considered DRL, in Gy·cm2, is 94.6(SD 119)-CAT, 88.6(SD 121)-PTCA and 33.0(SD 47.6)-CAT/PTCA. In considering KAP-BMI individual values, one obtain the min-max ranges, in Gy·cm2, 3.2-BMI A to 101-BMI B for CAT, 65-BMI A to 102-BMI F for PTCA and 10.4-BMI A to 59.2-BMI E for CAT/PTCA. The KAP-BMI approach has shown to be feasible as a DRL optimization process.

Comparison of radiation dose and its correlates between coronary computed tomography angiography and invasive coronary angiography in Northeastern Thailand

Background

The number of coronary computed tomography angiography (CCTA) exams is steadily growing. A novel computed tomography (CT) system has been developed to increase image quality while lowering patient radiation. The radiation dose attributed to CCTA has received considerable attention, whereas the dose associated with invasive catheter angiography (ICA) has received less. This study aims to investigate the radiation exposure of CCTA in patients and compare it to ICA.

Results

The mean effective dose of CCTA was 2.88 ± 0.85 mSv which was significantly lower than the mean effective dose of ICA (5.61 ± 0.55 mSv), p < 0.0001. The effective dose of CCTA correlated with the weight, height, and BMI, while the effective dose of ICA was associated with patient weight and BMI. The radiation exposure from CCTA has been considerably reduced over the last ten years by almost 2.5 folds. The mean radiation dose from the newer generation CT used in 2019 was significantly lower than that of the single-source CT in 2010 (2.88 ± 0.85 mSv vs. 7.15 ± 3.4 mSv, p < 0.001).

Conclusions

CCTA allows evaluation of CAD with a significantly less effective radiation dose to patients than diagnostic ICA. There was a significant decrease in radiation dose from CCTA over time. Regular measurement of patient doses is an essential step to optimize exposure. It makes operators aware of their performance and allows comparisons with generally accepted practices.

Radiation exposure during angiographic interventions in interventional radiology - risk and fate of advanced procedures

PURPOSE

Advanced angiographic procedures in interventional radiology are becoming more important and are more frequently used, especially in the treatment of several acute life-threatening diseases like stroke or aortic injury. In recent years, technical advancement has led to a broader spectrum of interventions and complex procedures with longer fluoroscopy times. This involves the risk of higher dose exposures, which, in rare cases, may cause deterministic radiation effects, e.g. erythema in patients undergoing angiographic procedures. Against this background, these procedures recently also became subject to national and international regulations regarding radiation protection. At the same time, individual risk assessment of possible stochastic radiation effects for each patient must be weighed up against the anticipated benefits of the therapy itself. Harmful effects of the administered dose are not limited to the patient but can also affect the radiologist and the medical staff. In particular, the development of cataracts in interventionalists is a rising matter of concern. Furthermore, long-term effects of repeated and prolonged x-ray exposure have long been neglected by radiologists but have come into focus in the past years.

CONCLUSIONS

With all this in mind, this review discusses different efforts to reduce radiation exposition levels for patients and medical staff by means of technical, personal as well as organizational measures.

Patient exposure dose in interventional cardiology per clinical and technical complexity levels. Part 1: results of the VERIDIC project

BACKGROUND

Patients can be exposed to high skin doses during complex interventional cardiology (IC) procedures.

PURPOSE

To identify which clinical and technical parameters affect patient exposure and peak skin dose (PSD) and to establish dose reference levels (DRL) per clinical complexity level in IC procedures.

MATERIAL AND METHODS

Validation and Estimation of Radiation skin Dose in Interventional Cardiology (VERIDIC) project analyzed prospectively collected patient data from eight European countries and 12 hospitals where percutaneous coronary intervention (PCI), chronic total occlusion PCI (CTO), and transcatheter aortic valve implantation (TAVI) procedures were performed. A total of 62 clinical complexity parameters and 31 technical parameters were collected, univariate regressions were performed to identify those parameters affecting patient exposure and define DRL accordingly.

RESULTS

Patient exposure as well as clinical and technical parameters were collected for a total of 534 PCI, 219 CTO, and 209 TAVI. For PCI procedures, body mass index (BMI), number of stents ≥2, and total stent length >28 mm were the most prominent clinical parameters, which increased the PSD value. For CTO, these were total stent length >57 mm, BMI, and previous anterograde or retrograde technique that failed in the same session. For TAVI, these were male sex, BMI, and number of diseased vessels. DRL values for Kerma-area product (P_KA), air kerma at patient entrance reference point (K_a,r), fluoroscopy time (FT), and PSD were stratified, respectively, for 14 clinical parameters in PCI, 10 in CTO, and four in TAVI.

CONCLUSION

Prior knowledge of the key factors influencing the PSD will help optimize patient radiation protection in IC.

Establishing a priori and a posteriori predictive models to assess patients' peak skin dose in interventional cardiology. Part 2: results of the VERIDIC project

BACKGROUND

Optimizing patient exposure in interventional cardiology is key to avoid skin injuries.

PURPOSE

To establish predictive models of peak skin dose (PSD) during percutaneous coronary intervention (PCI), chronic total occlusion percutaneous coronary intervention (CTO), and transcatheter aortic valve implantation (TAVI) procedures.

MATERIAL AND METHODS

A total of 534 PCI, 219 CTO, and 209 TAVI were collected from 12 hospitals in eight European countries. Independent associations between PSD and clinical and technical dose determinants were examined for those procedures using multivariate statistical analysis. A priori and a posteriori predictive models were built using stepwise multiple linear regressions. A fourfold cross-validation was performed, and models' performance was evaluated using the root mean square error (RMSE), mean absolute percentage error (MAPE), coefficient of determination (R²), and linear correlation coefficient (r).

RESULTS

Multivariate analysis proved technical parameters to overweight clinical complexity indices with PSD mainly affected by fluoroscopy time, tube voltage, tube current, distance to detector, and tube angulation for PCI. For CTO, these were body mass index, tube voltage, and fluoroscopy contribution. For TAVI, these parameters were sex, fluoroscopy time, tube voltage, and cine acquisitions. When benchmarking the predictive models, the correlation coefficients were r = 0.45 for the a priori model and r = 0.89 for the a posteriori model for PCI. These were 0.44 and 0.67, respectively, for the CTO a priori and a posteriori models, and 0.58 and 0.74, respectively, for the TAVI a priori and a posteriori models.

CONCLUSION

A priori predictive models can help operators estimate the PSD before performing the intervention while a posteriori models are more accurate estimates and can be useful in the absence of skin dose mapping solutions.

ESTIMATION OF PATIENT RADIATION DOSES FROM MULTI-DETECTOR COMPUTED TOMOGRAPHY ANGIOGRAPHY PROCEDURES IN TANZANIA

The aim of the present study was to estimate the volume CT dose index (CTDIvol), dose length product (DLP) and effective dose (ED) to patients from five multi-detector computed tomography angiography (MDCTA) procedures: brain, carotid, coronary, entire aorta and lower limb from four medical institutions in Tanzania; to compare these doses to those reported in the literature, and to compare the data obtained with ICRP 103 and Monte Carlo software. The radiation doses for 217 patients were estimated using patient demographics, patient-related exposure parameters, the geometry of examination and CT-Expo V 2.4 Monte Carlo-based software. The median values of the CTDIvol, DLP and ED for MDCTA procedures of the brain and carotids were 36.8 mGy, 1481.0 mGy∙cm and 5.2 mSv, and 15.9 mGy, 1224.0 mGy∙cm and 7.8 mSv, respectively; while for the coronary, entire aortic, and lower limbs were 49.4 mGy, 1493.0 mGy∙cm and 30.6 mSv; 16.2 mGy, 2287.0 mGy∙cm and 41.1 mSv; and 6.4 mGy, 1406.0 mGy∙cm and 10.5 mSv, respectively. The ratio of the maximum to minimum ED values to individual patients across the four medical centers were 41.4, 11.1, 4.6, 9.5 and 37.4, respectively, for the brain, carotid, coronary, entire aortic and lower limb CT angiography procedures. The mean values of CTDIvol, DLP and ED in the present study were typically higher than the values reported from Kenya, Korea and Saudi Arabia. The 75th percentile values of the DLP were above the preliminary diagnostic references levels proposed by Kenya, Switzerland and Korea. The observed wide range of examination scanning protocols and patient doses for similar MDCTA procedures within and across hospitals; and the observed relatively high patient doses compared to those reported in the literature, call for the need to standardize scanning protocols and optimise patient dose from MDCTA procedures.

Assessment of eye doses to staff involved in interventional cardiology procedures in Kuwait

In this study, which is the first of its kind in the gulf region, eye doses of interventional cardiologists and nurses were measured using active dosimeters for left and right eyes, in 60 percutaneous coronary interventions in three main hospitals in Kuwait. The dose given in terms of H_p(0.07) per procedure when ceiling suspended screens were used by main operators ranged from 18.5 to 30.3 µSv for the left eye and from 12.6 to 23.6 µSv for the right eye. Taking into account typical staff workload, the results show that the dose limit of 20 mSv/year to the eyes can be exceeded for interventional cardiologists in some situations, which demonstrates the need of using additional effective radiation protection tools, e.g. protective eye spectacles, in addition to the regular and proper use of ceiling suspended screens. With indications of increase in workload, the need for availability of a dedicated active dosimeter for the regular monitoring of eye doses is emphasized.

Establishing a diagnostic reference level of radiation dose in coronary angiography and intervention: A prospective evaluation

INTRODUCTION

Invasive Coronary Angiography (CAG) leads to significant radiation exposure to the patients. Guidelines suggest that a local landmark or Diagnostic Reference Level (DRL) for these procedures should be established for every region and country. This study attempts to create a DRL for a tertiary care hospital, acting as an interim DRL for the country/region.

METHODS

Radiation exposure data for all coronary procedures done at a tertiary care hospital between October 2016 to September 2018 were collected. Data was segregated into diagnostic Coronary Angiography (CAG) and single-vessel Percutaneous Intervention (PCI). The parameters collected include dose surface product (PKA), skin surface entry dose (KAR), and fluoroscopy time (FT). The 75th percentile of the PKA was used to define the DRL.

RESULTS

500 Patients were included in the CAG group, in which the Median KAR was 412.05 mGy, Median PKA was 2635.7 μGysqm, and median FT was 2.25 min. The DRL for coronary angiography was calculated as 3695.1 μGysqm. Two hundred fifty patients were in the PCI group, the Median KAR was 1649 mGy, Median PKA was 8822.1 μGysqm, the median FT being 8.2 min. The DRL for single-vessel coronary intervention was calculated as 11038 μGysqm.

CONCLUSION

This study establishes a benchmark for radiation dose for diagnostic coronary angiography and single-vessel coronary intervention at a tertiary care hospital in NCR. It establishes an interim DRL that can be used for future studies in other institutions in the region and country and to compare with other countries.

The empirical formula for calculating the incident air Kerma in intraoral radiographic imaging

OBJECTIVES

The aim of this paper is to determine the empirical formula for calculating the incident air kerma (Ki), used as a patient dose descriptor in the intraoral radiographic imaging.

METHODS

The data for the formula were collected during the regular annual inspection of intraoral dental X-ray units in 2018, 2019 and early 2020. The measurement data of 50 X-ray units were processed to develop the formula. Exposure factors for imaging molars of the upper jaw of an average patient in a clinical setting were used in the measurement. The formula validity was statistically evaluated using coefficient of correlation, standard error of the fitted function and the mean relative percentage deviation.

RESULTS

The measurement values of the radiation doses and calculated values obtained by using the final formula showed good agreement - the mean relative percentage deviation values less than ±15%.

CONCLUSIONS

Although there are differences in X-ray units, voltages, manufacturers and device architectures (single-phase and high-frequency), the measurement data comply well with computed ones in all cases.

ESTIMATION OF OCCUPATIONAL RADIATION EXPOSURE FOR MEDICAL WORKERS IN RADIOLOGY AND CARDIOLOGY IN THE UNITED ARAB EMIRATES: NINE HOSPITALS EXPERIENCE

PURPOSE

Occupational radiation exposure for medical workers in radiology and cardiology was analyzed in nine hospitals in the UAE between 2002 and 2016. The purpose of the study was to determine the time trend and the differences in occupational radiation exposure among worker groups and hospitals in the country.

METHODS

Readings of 5700 thermoluminescence dosimeters (TLDs) were obtained from 1011 medical workers and grouped into 5 worker groups (radiographers, diagnostic radiologists, nurses, cardiologists and physicians).

RESULTS

The mean annual effective dose was from 0.38 to 0.62 mSv per worker. Even though an increase in the collective effective dose has been noticed during the study period, no significant time trend was observed in the mean effective dose. Furthermore, cardiologists received higher mean and maximum effective doses than the other worker groups.

CONCLUSION

The annual effective doses were below the limits set by national legislation and international standards, and for the average worker, the likelihood of high exposure is small. However, improvements in radiation protection practices could be implemented to reduce occupational radiation dose to cardiologists, who were the most exposed worker group in this study.

Development of Novel Real-Time Radiation Systems Using 4-Channel Sensors

Radiation-related tissue injuries after medical radiation procedures, such as fluoroscopically guided intervention (FGI), have been reported in patients. Real-time monitoring of medical radiation exposure administered to patients during FGI is important to avoid such tissue injuries. In our previous study, we reported a novel (prototype) real-time radiation system for FGI. However, the prototype sensor indicated low sensitivity to radiation exposure from the side and back, although it had high-quality fundamental characteristics. Therefore, we developed a novel 4-channel sensor with modified shape and size than the previous sensor, and evaluated the basic performance (i.e., measured the energy, dose linearity, dose rate, and angular dependence) of the novel and previous sensors. Both sensors of our real-time dosimeter system demonstrated the low energy dependence, excellent dose linearity (R2 = 1.0000), and good dose rate dependence (i.e., within 5% statistical difference). Besides, the sensitivity of 0° ± 180° in the horizontal and vertical directions was almost 100% sensitivity for the new sensor, which significantly improved the angular dependence. Moreover, the novel dosimeter exerted less influence on X-ray images (fluoroscopy) than other sensors because of modifying a small shape and size. Therefore, the developed dosimeter system is expected to be useful for measuring the exposure of patients to radiation doses during FGI procedures.

Local Diagnostic Reference Levels in Interventional Radiology

PURPOSE

Interventional cardiology procedures, during which live images are acquired, involve exposure to x-rays. The use of fluoroscopy can cause high radiation doses to patients and operators because of the prolonged duration of x-ray emission. For this reason, special attention and constant vigilance represent challenges for commissions and groups of experts in the field. The purpose of this study is to establish local diagnostic reference levels (DRLs) for these procedures, to improve radiological practice, and to optimize radiation doses.

METHODS

This work was carried out in two university hospitals and two private medical facilities in Rabat, the capital of Morocco, during the period 2017-2018. The study concerns 657 interventional cardiology procedures (457 coronary angiography [CA] and 200 percutaneous transluminal coronary angioplasty [PTCA]), performed by 11 cardiologists on different installations in 5 catheterization rooms. The data collected for each procedure were patient age, height and weight, dosimeter indicators in terms of dose area product (P_KA), total air kerma at the reference point (K_ar), fluoroscopy time (FT), and the number of frames, together with the primary beam parameters as kV and total mAs. The proposed DRLs were set from the 75th percentile of the P_KA and FT.

RESULTS

The mean of P_KA for CA and PTCA procedures were 29.2 Gy∗cm² and 70.4 Gy∗cm², respectively, the mean of fluoroscopy time were 4.0 min and 12.17 min for 334 and 685 frames, respectively. Results for the local DRLs were 37.3 and 87.1 Gy cm² for P_KA and 4.48 and 16.15 min for FT, corresponding to CA and PTCA procedures.

CONCLUSION

This work focuses on proposing local DRLs in Morocco for CA and PTCA procedures. The results show that the values found conform with those of international studies.

OCCUPATIONAL RADIATION EXPOSURE DOSE OF THE EYE IN DEPARTMENT OF CARDIAC ARRHYTHMIA PHYSICIAN

Interventional radiology (IR) procedures tend to be complex, which delivers high radiation exposure to patient. In the present study, we measured the radiation exposure dose [Hp(3)] in the eye using a direct eye dosemeter placed next to the physician's eye during procedures. Physicians wore a direct eye dosemeter just lateral to eyes and an additional direct eye dosemeter outside the radiation protective eyeglasses close to their eyes. Additionally, a neck glass badge was worn at the neck. Although we found a positive correlation between the left neck glass badge dose [Hp(0.07)] and the left eye lens dose [Hp(3)], the value of R2 of the regression equation were 0.62 and 0.71 (outside and inside). We thought that the exact eye lens dose might not be estimated from the neck glass badge. In conclusion, a correct evaluation of the lens dose [Hp(3)] using the direct eye dosemeter is recommended for tachyarrhythmia physicians.

OCCUPATIONAL RADIATION EXPOSURE OF THE EYE IN NEUROVASCULAR INTERVENTIONAL PHYSICIAN

Neurovascular interventional radiology (neuro-IR) procedures tend to require an extended fluoroscopic exposure time and repeated digital subtraction angiography. To evaluate the actual measurement of eye lens dose using a direct eye dosemeter in neuro-IR physicians is important. Direct dosimetry using the DOSIRIS™ (IRSN, France) [3 mm dose equivalent, Hp(3)] was performed on 86 cases. Additionally, a neck personal dosemeter (glass badge) [0.07 mm dose equivalent, Hp(0.07)] was worn outside the protective apron to the left of the neck. The average doses per case of neuro-IR physicians were 0.04 mSv/case and 0.02 mSv/case, outside and inside the radiation protection glasses, respectively. The protective effect of radiation protection glasses was approximately 60%. The physician eye lens dose tended to be overestimated by the neck glass badge measurements. A correct evaluation of the lens dose [Hp(3)] using an eye dosemeter such as DOSIRIS™ is needed for neuro-IR physicians.

INTERVENTIONAL RADIOLOGICAL PROCEDURES MOST PRONE TO CAUSE HIGH PATIENT PEAK SKIN DOSES BASED ON REVIEW OF 7607 PROCEDURES

Peak skin doses to patients undergoing interventional radiological procedures in a 3-year period were assessed to identify the most critical procedures and evaluate probability for occurrence of radiation-induced tissue injuries. Data of 7607 patients were reviewed, identifying those with cumulative air kerma at a reference point (Ka,r) exceeding 3 Gy. Observed tissue injuries in patients with exceeded levels were gathered by a questionnaire. Ka,r exceeded 3 Gy in 145 patients, all during vascular procedures; most frequently in preparations for liver radioembolization (SIRT), transjugular intrahepatic portosystemic shunt (TIPS), endovascular abdominal aortic repair (EVAR), adrenal venous sampling (AVS), endovascular thoracic aortic repair (TEVAR) and embolizations in abdominal/pelvic area (30, 21.4, 13.4, 12.6, 9.6 and 3.5% of patients, respectively). A total of 10 patients, extrapolating to ~0.6% of all patients, reported tissue injuries. During interventional radiological procedures threshold for radiation-induces tissue injuries can be exceeded in a significant number of patients (1.9%). Tissue injuries were reported approximately three times less frequently than anticipated; their severity was poorly related to those expected.

New real-time patient radiation dosimeter for use in radiofrequency catheter ablation

In a previous study, we reported on a novel (prototype) real-time patient dosimeter with non-toxic phosphor sensors. In this study, we developed new types of sensors that were smaller than in the previous prototype, and clarified the clinical feasibility of our newly proposed dosimeter. Patient dose measurements obtained with the newly proposed real-time dosimeter were compared with measurements obtained using a calibrated radiophotoluminescence glass reference dosimeter (RPLD). The reference dosimeters were set at almost the same positions as the new real-time dosimeter sensors. We found excellent correlations between the reference RPLD measurements and those obtained using our new real-time dosimeter (r2 = 0.967). However, the new type of dosimeter was found to underestimate radiation skin dose measurements when compared with an RPLD. The most probable reason for this was the size reduction in the phosphor sensor of the new type of dosimeter. We believe that, as a result of reducing the phosphor sensor size, the backscattered X-ray irradiation was underestimated. However, the new dosimeter can accurately determine the absorbed dose by correcting the measured value with calibration factors. The calibration factor for the new type dosimeter was determined (by linear regression) to be ~1.15. New real-time patient dosimeter design would be an effective tool for the real-time measurement of patient skin doses during interventional radiology treatments.

Development and validation of a psychometric scale for assessing healthcare professionals' knowledge in radiation protection

INTRODUCTION

Healthcare professionals must sufficiently understand ionising radiation and the associated protection measures to avoid unnecessarily exposing patients and staff to ionising radiation. Hence, a proper safety culture is important to lowering health risks. The development and establishment of an instrument that can indicate healthcare professionals' understanding/knowledge of radiation protection concepts can greatly contribute to a good safety culture. The purpose of the present study was to develop and psychometrically test the Healthcare Professional Knowledge of Radiation Protection (HPKRP) self-evaluation scale, which was designed to measure the knowledge level of radiation protection by healthcare professionals working with ionising radiation in a clinical environment.

METHODS

The presented research employed a cross-sectional study design. Data were collected from eight Finnish hospitals in 2017. A total of 252 eligible nurses responded to the newly developed HPKRP scale. The face and content validity were tested with the Content Validity Index (CVI). Explorative factor analysis was used to test construct validity, whereas reliability was tested with Cronbach's alpha.

RESULTS

Overall S-CVI for the HPKRP scale was 0.83. Exploratory factor analysis revealed a three-factor model for the HcPCRP scale containing 33 items. The first factor was defined by Radiation physics and principles of radiation usage, the second factor by Radiation protection, and the third factor by Guidelines of safe ionising radiation usage. These three factors explained 72% of the total variance. Cronbach's alpha coefficient for the scale ranged from 0.93 to 0.96.

CONCLUSION

The results provide strong evidence for the validity and reliability of the HPKRP scale. Additionally, educators can use the scale to evaluate healthcare students' understanding in radiation safety before and after education.

PRELIMINARY INVESTIGATION OF RADIATION DOSE TO PATIENTS FROM CARDIOVASCULAR INTERVENTIONAL PROCEDURES IN TANZANIA

Although contemporary cardiac X-ray exams are typically set so benefits outweighs the risk, the growing use and increasing complexity of the cardiovascular interventional radiological (CVIR) procedures does increase the risk of radiation-related tissue effects and stochastic effects to the individual patients and the population. In view of these radiological concerns there is a need to investigate factors that influence the doses received by the patients and enable optimisation needed. The air kerma area product (KAP), cumulative air kerma (CAK) and fluoroscopy time (FT) to patients from two major CVIR procedures: coronary angiography (CA) and percutaneous coronary interventions (PCI), were obtained from two major hospitals in Tanzania. The CAK and KAP were determined using ionisation chambers equipped in each angiographic unit. The median values of the KAP, CAK and FT for the CA procedures were 37.8 Gy cm2, 425.5 mGy and 7.6 min, respectively, while for the PCI were 86.5 Gy cm2, 1180.3 mGy and 19.0 min, respectively. The overall differences among individual KAP, CAK and FT values across the two hospitals investigated differed by factors of up to 33.5, 58.7 and 26.3 for the CA, while for the PCI procedures differed by factors of up to 10.9, 25.3 and 13.8, respectively. The mean values of KAP and FT for both CA and PCI were mostly higher than those reported values for Ireland, Belgium, Greece, France, China and Australia. The third quartiles of the KAP, CAK and FT for both CA and PCI were relatively above the preliminary diagnostic reference levels proposed by the IAEA, DIMOND III and SENTINEL. The observed substantial variations of mean values of technical parameters and patient doses (KAP, CAK and FT values) observed for the CA and PCI procedures inter and intra-hospitals were mainly explained by the complexity of the CVIR procedures, the nature of pathology, patient-specific characteristics, the variation in levels of skills and experiences among IC personnel, and the different procedural protocols employed among interventional cardiologists and hospitals. The observed great variations of procedural protocols and patient doses within and across the hospitals and relative higher dose than reported values from the literature call for the need to optimise radiation dose to patient from IC procedures.

The International Atomic Energy Agency action plan on radiation protection of patients and staff in interventional procedures: Achieving change in practice

INTRODUCTION

The International Atomic Energy Agency (IAEA) organized the 3rd international conference on radiation protection (RP) of patients in December 2017. This paper presents the conclusions on the interventional procedures (IP) session.

MATERIAL AND METHODS

The IAEA conference was conducted as a series of plenary sessions followed by various thematic sessions. "Radiation protection of patients and staff in interventional procedures" session keynote speakers presented information on: 1) Risk management of skin injuries, 2) Occupational radiation risks and 3) RP for paediatric patients. Then, a summary of the session-related papers was presented by a rapporteur, followed by an open question-and-answer discussion.

RESULTS

Sixty-seven percent (67%) of papers came from Europe. Forty-four percent (44%) were patient studies, 44% were occupational and 12% were combined studies. Occupational studies were mostly on eye lens dosimetry. The rest were on scattered radiation measurements and dose tracking. The majority of patient studies related to patient exposure with only one study on paediatric patients. Automatic patient dose reporting is considered as a first step for dose optimization. Despite efforts, paediatric IP radiation dose data are still scarce. The keynote speakers outlined recent achievements but also challenges in the field. Forecasting technology, task-specific targeted education from educators familiar with the clinical situation, more accurate estimation of lens doses and improved identification of high-risk professional groups are some of the areas they focused on.

CONCLUSIONS

Manufacturers play an important role in making patients safer. Low dose technologies are still expensive and manufacturers should make these affordable in less resourced countries. Automatic patient dose reporting and real-time skin dose map are important for dose optimization. Clinical audit and better QA processes together with more studies on the impact of lens opacities in clinical practice and on paediatric patients are needed.

Impact of low dose settings on radiation exposure during pediatric fluoroscopic guided interventions

PURPOSE

To evaluate the effects of lowering the detector entrance exposure in children undergoing interventional radiology procedures.

MATERIALS AND METHODS

The study retrospectively investigated radiation dose levels in pediatric patients aged 0-18 years before (n = 39) and after (n = 26) lowering detector entrance dose, undergoing embolization of peripheral Arteriovenous malformations, Portal Vein Interventions or Percutaneous Transhepatic Cholangio Drainage (PTCD) between 2014 and 2017. Patient characteristics, fluoroscopy time, protocols used as well as resulting Skin Dose and Dose Area Product (DAP) were compared in each cohort. Image quality was assessed by two independent readers.

RESULTS

The two patient cohorts did not differ in terms of patient demographics. Similarly, fluoroscopy time did not differ before and after implementation of the low dose settings. An overall reduction of skin dose of 75.1% for AVM embolizations, 80.5% for Portal Vein Interventions and 85.3% for PTCD placement was observed. The DAP decrease was 82.5% for AVM embolizations, 72.2% for Portal Vein Interventions and 79.8% for PTCD placement. Image quality was generally considered to be good with an insignificant difference between pre and post implementation of the low dose approach and good agreement between the two readers. Manual inroom-switching to higher dose levels was possible, however this was not performed more frequently after implementation of the low dose settings.

CONCLUSION

Lowering the detector entrance dose in pediatric interventional radiology procedures results in a significant decrease of the radiation dose burden.

Patient dose monitoring and the use of diagnostic reference levels for the optimization of protection in medical imaging: current status and challenges worldwide

Optimization is one of the key concepts of radiation protection in medical imaging. In practice, it involves compromising between the image quality and dose to the patient; the dose should not be higher than necessary to achieve an image quality (or diagnostic information) needed for the clinical task. Monitoring patient dose is a key requirement toward optimization. The concept of diagnostic reference level (DRL) was introduced by the International Commission on Radiological Protection as a practical tool for optimization. Unfortunately, this concept has not been applied consistently worldwide. To review the current strengths and weaknesses worldwide and to promote improvements, the International Atomic Energy Agency organized a Technical Meeting on patient dose monitoring and the use of DRLs on May 2016. This paper reports a summary of the findings and conclusions from the meeting. The strengths and weaknesses were generally different in less-developed countries compared with developed countries. Possible improvements were suggested in six areas: human resources and responsibilities, training, safety and quality culture, regulations, funding, and tools and methods. An overall conclusion was that radiation protection requires a patient-centric approach and a transfer from purely reactive to increasingly proactive optimization, whereby the best outcome is expected from good teamwork.

Estimated collective effective dose to the population from nuclear medicine diagnostic procedures in Croatia: A comparison of 2010 and 2015

OBJECTIVE

This study presents national surveys of patient exposure from nuclear medicine (NM) diagnostic procedures in 2010 and 2015 in the Republic of Croatia.

METHODS

The survey was performed according to the European Commission Dose DataMed (DDM) project methodology. 28 most frequent NM diagnostic procedures were identified. Data about frequencies of procedures and average administered activities of radioisotopes used in those procedures were collected. Average administered activities were converted to effective doses according to the dose conversion coefficients. Then the collective effective dose to the population and an effective dose per capita were calculated based on the number of the most frequent NM diagnostic procedures and the average effective dose per procedure.

RESULTS

In 2010, 41200 NM diagnostic procedures led to 146.7 manSv collective effective dose to the population and in 2015, 42000 NM diagnostic procedures led to 146.8 manSv collective effective dose to the population. The frequencies of NM diagnostic procedures were 9.7 and 9.8 annually per 1000 population with 34.1 μSv and 34.2 μSv effective dose per capita for 2010 and 2015, respectively. The main contributors to the annual collective dose from NM in Croatia are examinations of the bone, heart, thyroid and PET/CT tumour diagnostic. Average administered activities have not changed considerably from 2010 to 2015. Nevertheless, within the frequency of some of the procedures, significant changes were found in five-year period.

CONCLUSIONS

Frequencies, average administered activities and collective effective dose to the population from NM diagnostic procedures in Croatia are comparable to the values reported by other European surveys. Changes were found between 2010 and 2015 and we intend to perform this study periodically to identify possible trends, but also to raise awareness about the potential dose optimization.

Review of the current status of radiation protection in diagnostic radiology in Africa

The aim of this paper is to review the available published studies from African countries on patient doses and medical radiation protection and identify strengths, weaknesses, and challenges. Papers on radiation doses to patients published until 2016 pertaining to studies in African countries were reviewed. Radiography, interventional radiology, computed tomography (CT), and mammography modalities were covered. In radiography, the entrance surface air kerma values were below the established diagnostic reference levels (DRLs) provided by the International Atomic Energy Agency, European Commission, and National Council on Radiation Protection and Measurements. Patient and staff doses in interventional procedures were not on the higher side when compared with other published reports from developed countries. The dose length product values in CT in many situations were higher than established DRLs. In mammography, the variations of clinical image quality and dose to standard breast between African countries and other countries were insignificant. In conclusion, like in any continent, not all countries in Africa are active, but some have produced good results. The potential for optimization of radiation protection using simple and inexpensive techniques has been demonstrated. The lack of medical physicists is one of the important challenges.

A Useful Gadget to Reduce the Radiation Dose of Interventionist's Hands

Increased demand for interventional radiology techniques has interventionists performing a large number of these procedures. Measurements and calculations have shown that the radiation doses received by these specialists can exceed the threshold of radiation-induced deterministic effects unless radiation protection procedures and devices are used. Proper usage of radiation protection devices can protect them from radiation-induced effects, even with a high workload. Occupational radiation protection entails proper training of interventionists to increase their awareness about available appropriate protection tools and equipment, and devices that can be used to minimize exposure, such as needle holders, tubing extensions, and injectors. This study introduces a device that can be used to fix the catheter to prevent the physician from holding the catheter by hand. The authors, also, discuss the importance of radiation protection training along with the training on new medical equipment, which can be applied to reduce the radiation dose.

Initial Investigation of Factors Influencing Radiation Dose to Patients Undergoing Barium-Based Fluoroscopy Procedures in Tanzania

The aim of this study was to investigate the nature and causes of radiation dose imparted to patients undergoing barium-based X-ray fluoroscopy procedures in Tanzania and to compare these doses to those reported in the literature from other regions worldwide. The air kerma area product (KAP) to patient undergoing barium investigations of gastrointestinal tract system was obtained from four consultant hospitals. The KAP was determined using a flat transparent transmission ionization chamber. Mean values of KAP for barium swallow (BS), barium meal (BM) and barium enema (BE) were 2.79, 2.62 and 15.04 Gy cm2, respectively. The mean values of KAP per hospital for the BS, BM and BE procedures varied by factors of up to 7.3, 1.6 and 2.0, respectively. The overall difference between individual patient doses across the four consultant hospitals investigated differed by factors of up to 53, 29.5 and 12 for the BS, BM and BE procedures, respectively. The majority of the mean values of KAP was lower than the reported values for Ghana, Greece, Spain and the UK, while slightly higher than those reported for India. The observed wide variation of KAP values for the same fluoroscopy procedure within and among the hospitals was largely attributed to the dynamic nature of the procedures, the patient characteristics, the skills and experience of personnel, and the different examination protocols employed among hospitals. The observed great variations of procedural protocols and patient doses within and across the hospitals call for the need to standardize examination protocols and optimize barium-based fluoroscopy procedures.

Survey of Effective Doses to Patients Undergoing Contrast-Based X-ray Fluoroscopy Procedures in Tanzania

The aim of this study was to assess the radiation burden imparted to patients from contrast-based X-ray fluoroscopy procedures in Tanzania. The effective doses (EDs) to patients from five contrast-based fluoroscopy procedures were obtained from four hospitals. The ED was estimated using the knowledge of the patient characteristics, patient-related exposure parameters, measurements of air kerma area product and PCXCM software. The median EDs for the barium swallow (BS), barium meal (BM), barium enema (BE), hysterosalpingography (HSG) and retrograde urethrography (RUG) were 0.50, 1.43, 2.83, 0.65 and 0.59 mSv, respectively. The median ED per hospital for the BS and BM procedures varied by factors of up to 9.9 and 4.2, respectively, while for the BE, HSG and RUG varied by factors of up to 2.3, 2.4 and 4.3, respectively. The overall differences between individual EDs across the four hospitals varied by factors of up to 53, 58.9 and 11.4 for the BS, BM and BE, respectively, while for the HSG and RUG differed by factors of up to 22 and 46.7, respectively. The mean EDs in this study were mostly lower than reported values from Spain, the UK, Ghana and Greece, while slightly higher than those reported from India. The observed wide variations of procedural protocols and patient doses within and across the hospitals; and the observed high patient doses in this study relative to those from the literature call for the need to standardize procedural protocols and optimize contrast-based fluoroscopy procedures.

Patient radiation doses and reference levels in pediatric interventional radiology

OBJECTIVES

To describe, in a multicentric paediatric population, reference levels (RLs) for three interventional radiological procedures.

METHODS

From January 2012 to March 2015, children scheduled for an interventional radiological procedure in two French tertiary centres were retrospectively included and divided into four groups according to age: children younger than 2 years (A1), aged 2-7 years (A5), 8-12 years (A10) and 13-18 years (A15). Three procedures were identified: cerebral digital subtraction angiography (DSA), brain arteriovenous malformation (bAVM) embolization, and head and neck superficial vascular malformation (SVM) percutaneous sclerotherapy. Demographic and dosimetric data, including dose area product (DAP), were collected.

RESULTS

550 procedures were included. For DSA (162 procedures), the proposed RL values in DAP were 4, 18, 12 and 32 Gy∙cm² in groups A1, A5, A10 and A15, respectively. For bAVM embolization (258 procedures), values were 33, 70, 105 and 88 Gy∙cm² in groups A1, A5, A10 and A15, respectively. For SVM sclerotherapy (130 procedures), values were 350, 790, 490 and 248 mGy∙cm² in groups A1, A5, A10 and A15, respectively.

CONCLUSION

Consecutive data were available to permit a proposal of reference levels for three major paediatric interventional radiology procedures.

KEY POINTS

• We determined reference levels (RLs) for bAVM embolization, DSA and SVM sclerotherapy. • The proposed RLs will permit benchmarking practice with an external standard. • The proposed RLs by age may help to develop paediatric dose guidelines.

Computed tomography and patient risk: Facts, perceptions and uncertainties

Since its introduction in the 1970s, computed tomography (CT) has revolutionized diagnostic decision-making. One of the major concerns associated with the widespread use of CT is the associated increased radiation exposure incurred by patients. The link between ionizing radiation and the subsequent development of neoplasia has been largely based on extrapolating data from studies of survivors of the atomic bombs dropped in Japan in 1945 and on assessments of the increased relative risk of neoplasia in those occupationally exposed to radiation within the nuclear industry. However, the association between exposure to low-dose radiation from diagnostic imaging examinations and oncogenesis remains unclear. With improved technology, significant advances have already been achieved with regards to radiation dose reduction. There are several dose optimization strategies available that may be readily employed including omitting unnecessary images at the ends of acquired series, minimizing the number of phases acquired, and the use of automated exposure control as opposed to fixed tube current techniques. In addition, new image reconstruction techniques that reduce radiation dose have been developed in recent years with promising results. These techniques use iterative reconstruction algorithms to attain diagnostic quality images with reduced image noise at lower radiation doses.

Direct Effective Dose Calculations in Pediatric Fluoroscopy-Guided Abdominal Interventions with Rando-Alderson Phantoms - Optimization of Preset Parameter Settings

Objective

The aim of the study was to calculate the effective dose during fluoroscopy-guided pediatric interventional procedures of the liver in a phantom model before and after adjustment of preset parameters.

Methods

Organ doses were measured in three anthropomorphic Rando-Alderson phantoms representing children at various age and body weight (newborn 3.5kg, toddler 10kg, child 19kg). Collimation was performed focusing on the upper abdomen representing mock interventional radiology procedures such as percutaneous transhepatic cholangiography and drainage placement (PTCD). Fluoroscopy and digital subtraction angiography (DSA) acquisitions were performed in a posterior-anterior geometry using a state of the art flat-panel detector. Effective dose was directly measured from multiple incorporated thermoluminescent dosimeters (TLDs) using two different parameter settings.

Results

Effective dose values for each pediatric phantom were below 0.1mSv per minute fluoroscopy, and below 1mSv for a 1 minute DSA acquisition with a frame rate of 2 f/s. Lowering the values for the detector entrance dose enabled a reduction of the applied effective dose from 12 to 27% for fluoroscopy and 22 to 63% for DSA acquisitions. Similarly, organ doses of radiosensitive organs could be reduced by over 50%, especially when close to the primary x-ray beam.

Conclusion

Modification of preset parameter settings enabled to decrease the effective dose for pediatric interventional procedures, as determined by effective dose calculations using dedicated pediatric Rando-Alderson phantoms.

A cross-sectional study of the radiation dose and image quality of X-ray equipment used in IVR

There are case reports of injuries caused by the radiation from interventional radiology (IVR) X‐ray systems. Therefore, the management of radiation doses in IVR is important. However, no detailed report has evaluated image quality for a large number of IVR X‐ray systems. As a result, it is unclear whether the image quality of the X‐ray equipment currently used in IVR procedures is optimal. We compared the entrance surface doses and image quality of multiple IVR X‐ray systems. This study was conducted in 2014 at 13 medical facilities using 18 IVR X‐ray systems. We evaluated image quality and simultaneously measured the radiation dose. Entrance surface doses for fluoroscopy (duration, 1 min) and cineradiography (duration, 10 s) are measured using a 20‐cm‐thick acrylic plate and skin dose monitor. The image quality (such as spatial resolution and low‐contrast detectability) of both fluoroscopy and cineradiography was evaluated using a QC phantom. For fluoroscopy, the average entrance surface dose using the 20‐cm‐thick acrylic plate was 13.9 (range 2.1–28.2) mGy/min. For cineradiography, the average entrance surface dose was 24.6 (range 5.1–49.3) mGy/10 s. We found positive correlations between radiation doses and image quality scores, in general, especially for fluoroscopy. The differences in surface dose among the 18 IVR X‐ray systems were high (max/min, 9.7‐fold for cineradiography; 13.4‐fold for fluoroscopy). The differences in image quality scores (spatial resolution, low‐contrast detectability, and dynamic range) were also very large. In general, there tended to be a correlation between radiation dose and image quality. Periodical measurements of the radiation dose and image quality of the X‐ray equipment used for cineradiography and fluoroscopy in IVR are necessary. The need to minimize patient exposure requires that the dose be reduced to the minimum level that will generate an image with an acceptable degree of noise.

PACS number(s): 87.57.C, 87.57.uq, 87.59.B, 87.59.bf, 87.59.C, 87.59.cf, 87.59.Dj

A Rotatable Quality Control Phantom for Evaluating the Performance of Flat Panel Detectors in Imaging Moving Objects

As the use of diagnostic X-ray equipment with flat panel detectors (FPDs) has increased, so has the importance of proper management of FPD systems. To ensure quality control (QC) of FPD system, an easy method for evaluating FPD imaging performance for both stationary and moving objects is required. Until now, simple rotatable QC phantoms have not been available for the easy evaluation of the performance (spatial resolution and dynamic range) of FPD in imaging moving objects. We developed a QC phantom for this purpose. It consists of three thicknesses of copper and a rotatable test pattern of piano wires of various diameters. Initial tests confirmed its stable performance. Our moving phantom is very useful for QC of FPD images of moving objects because it enables visual evaluation of image performance (spatial resolution and dynamic range) easily.

Assessment of radiation protection of patients and staff in interventional procedures in four Algerian hospitals

This study was aimed to assess patient dosimetry in interventional cardiology (IC) and radiology (IR) and radiation safety of the medical operating staff. For this purpose, four major Algerian hospitals were investigated. The data collected cover radiation protection tools assigned to the operating staff and measured radiation doses to some selected patient populations. The analysis revealed that lead aprons are systematically worn by the staff but not lead eye glasses, and only a single personal monitoring badge is assigned to the operating staff. Measured doses to patients exhibited large variations in the maximum skin dose (MSD) and in the dose area product (DAP). The mean MSD registered values are as follows: 0.20, 0.14 and 1.28 Gy in endoscopic retrograde cholangiopancreatography (ERCP), coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA) procedures, respectively. In PTCA, doses to 3 out of 22 patients (13.6 %) had even reached the threshold value of 2 Gy. The mean DAP recorded values are as follows: 21.6, 60.1 and 126 Gy cm(2) in ERCP, CA and PTCA procedures, respectively. Mean fluoroscopic times are 2.5, 5 and 15 min in ERCP, CA and PTCA procedures, respectively. The correlation between DAP and MSD is fair in CA (r = 0.62) and poor in PTCA (r = 0.28). Fluoroscopic time was moderately correlated with DAP in CA (r = 0.55) and PTCA (r = 0.61) procedures. Local diagnostic reference levels (DRLs) in CA and PTCA procedures have been proposed. In conclusion, this study stresses the need for a continuous patient dose monitoring in interventional procedures with a special emphasis in IC procedures. Common strategies must be undertaken to substantially reduce radiation doses to both patients and medical staff.

Patient radiation doses during coronary interventions in four Croatian hospitals: 4-y comparison

The number of coronary interventions increased substantially in the recent years. Although of great benefit to patients, these procedures can subject patients to considerable radiation doses. There is a legal framework for patient dose measurements in Croatia during radiological procedures, but in practice, it applies only occasionally. A quality control manual, established at the University Hospital Osijek, was accepted by other major cardiology centres in Croatia; besides checking the technical characteristics of the device, it provides constant measurement and analysis of patient doses in interventional cardiology. It also includes patient examination for radiation skin injuries in case of dose of >2 Gy. The aim of the study was to determine and compare patient radiation doses during cardiological interventions measured within 4 y in four major cardiology centres with the values proposed by the European Commission and other professional bodies. The local reference dose levels were also set.

Radiation dose in coronary angiography and intervention: initial results from the establishment of a multi-centre diagnostic reference level in Queensland public hospitals

Introduction

Radiation dose to patients undergoing invasive coronary angiography (ICA) is relatively high. Guidelines suggest that a local benchmark or diagnostic reference level (DRL) be established for these procedures. This study sought to create a DRL for ICA procedures in Queensland public hospitals.

Methods

Data were collected for all Cardiac Catheter Laboratories in Queensland public hospitals. Data were collected for diagnostic coronary angiography (CA) and single-vessel percutaneous intervention (PCI) procedures. Dose area product (P_KA), skin surface entrance dose (K_AR), fluoroscopy time (FT), and patient height and weight were collected for 3 months. The DRL was set from the 75th percentile of the P_KA.

Results

2590 patients were included in the CA group where the median FT was 3.5 min (inter-quartile range = 2.3–6.1). Median K_AR = 581 mGy (374–876). Median P_KA = 3908 uGym² (2489–5865) DRL = 5865 uGym². 947 patients were included in the PCI group where median FT was 11.2 min (7.7–17.4). Median K_AR = 1501 mGy (928–2224). Median P_KA = 8736 uGym² (5449–12,900) DRL = 12,900 uGym².

Conclusion

This study established a benchmark for radiation dose for diagnostic and interventional coronary angiography in Queensland public facilities.

Radiation exposure in gastroenterology: improving patient and staff protection

Medical imaging involving the use of ionizing radiation has brought enormous benefits to society and patients. In the past several decades, exposure to medical radiation has increased markedly, driven primarily by the use of computed tomography. Ionizing radiation has been linked to carcinogenesis. Whether low-dose medical radiation exposure will result in the development of malignancy is uncertain. This paper reviews the current evidence for such risk, and aims to inform the gastroenterologist of dosages of radiation associated with commonly ordered procedures and diagnostic tests in clinical practice. The use of medical radiation must always be justified and must enable patients to be exposed at the lowest reasonable dose. Recommendations provided herein for minimizing radiation exposure are based on currently available evidence and Working Party expert consensus.