Patient radiation doses in interventional cardiology procedures

Typical dose values for intra-operative fluoroscopy during orthopaedic trauma surgery at Larnaca general hospital in cyprus: A five-year retrospective study

The purpose of this study was to establish typical dose values at orthopaedic operating rooms of the Larnaca General Hospital (LGH). Kerma area product (KAP), fluoroscopy time (FT) and cumulative air-kerma (Ka,r) measurements were collected for 821 patients who underwent common and reproducible trauma surgery over a five-year period, with three mobile C-arm systems; two equipped with an image-intensifier and one with a flat-panel detector. Dose indices were automatically extracted from radiation dose structured reports or DICOM meta-data files archived in the PACS, using custom-made software. The procedures were categorised based on the anatomical area and included foot/ankle, tibia/fibula, knee (distal femur, tibia plateau), femur/trochanter, hip, hand, radius/ulna, elbow, and humerus. The medians of KAP, FT and Ka,r were defined as typical dose values. Variations in dose values among the C-arm systems or different surgical operations involving femur/hip, tibia/fibula, and humerus were analysed as secondary outcomes. For the procedures on upper extremities, the typical dose values ranged between 20.1-197 mGycm2 for KAP, 4.50-14.5 s for FT and 0.07-0.71 mGy for Ka,r, whilst for the procedures on lower extremities ranged between 46.6-202 mGycm2 for KAP, 4.86-24.0 s for FT and 0.16-0.74 mGy for Ka,r. The largest values were reported for dynamic hip screw (889 mGycm2, 14.3 s, 3.10 mGy), and femur/trochanter intramedullary (long/short nail: 2007/1326 mGycm2, 52.3/36.0 s, 6.53/4.05 mGy) nailing, respectively. A decrease of up to 65 %, and 74 % was found in median KAP, and Ka,r, and an increase of up to 119 % (except knee's) in median FT values for the procedures performed with the flat-panel systems. Additionally, when comparing surgical operations, only femur/trochanter long/short and tibia intramedullary nailing demonstrated a significant increase in median KAP, FT and Ka,r values compared to dynamic hip screw and fixation with a locking plate, respectively. The typical dose values reported could be used as a guide to appropriate levels of intra-operative fluoroscopy in orthopaedic trauma surgery at LGH, and to encourage further optimisation by providing a baseline for audit of local practice in the absence of national reference doses. These values could also contribute to the establishment of the first national DRLs for orthopaedic trauma surgery.

An intuitive guidewire control mechanism for robotic intervention

PURPOSE

Teleoperated Interventional Robotic systems (TIRs) are developed to reduce radiation exposure and physical stress of the physicians and enhance device manipulation accuracy and stability. Nevertheless, TIRs are not widely adopted, partly due to the lack of intuitive control interfaces. Current TIR interfaces like joysticks, keyboards, and touchscreens differ significantly from traditional manual techniques, resulting in a shallow, longer learning curve. To this end, this research introduces a novel control mechanism for intuitive operation and seamless adoption of TIRs.

METHODS

An off-the-shelf medical torque device augmented with a micro-electromagnetic tracker was proposed as the control interface to preserve the tactile sensation and muscle memory integral to interventionalists' proficiency. The control inputs to drive the TIR were extracted via real-time motion mapping of the interface. To verify the efficacy of the proposed control mechanism to accurately operate the TIR, evaluation experiments using industrial grade encoders were conducted.

RESULTS

A mean tracking error of 0.32 ± 0.12 mm in linear and 0.54 ± 0.07° in angular direction were achieved. The time lag in tracking was found to be 125 ms on average using pade approximation. Ergonomically, the developed control interface is 3.5 mm diametrically larger, and 4.5 g. heavier compared to traditional torque devices.

CONCLUSION

With uncanny resemblance to traditional torque devices while maintaining results comparable to state-of-the-art commercially available TIRs, this research successfully provides an intuitive control interface for potential wider clinical adoption of robot-assisted interventions.

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.

Assessment of the Occupational Radiation Exposure of Anesthesia Staff in Interventional Cardiology

Introduction

This research seeks to evaluate the occupational radiation dose, quantified as the whole-body Annual Mean Effective Dose (AMED), received by anesthesia personnel in interventional cardiology.

Methods

Thermoluminescent dosimetry data was collected over five years (2019-2023) for a total of 175 anesthesia staff. Technologists comprised approximately 72.4% of the participants (55% male and 45% female), while consultants accounted for 27.6% (70% male and 30% female). Statistical tests, including Independent Samples T-Test and One-Way ANOVA, compared AMED across genders, job titles, and years.

Results

The study's findings on AMED across all staff from 2019 to 2023 showed marked variability in AMED. There was a significant rise in AMED from 0.72 mSv in 2019 to 0.92 mSv in 2020, then a decline to 0.82 mSv in 2021, with further decreases to 0.67 mSv in 2022 and finally to 0.65 mSv in 2023 (p < 0.001). The average AMED over the five-year span (2019-2023) was 0.76 ± 0.4 mSv. In terms of gender, the overall AMED for males was 0.73 ± 0.36 mSv and for females 0.79 ± 0.45 mSv, showing no significant statistical difference (p = 0.272). Significant differences in exposure were observed between the technologists who experienced a higher overall AMED (0.8 ± 0.43 mSv) compared to consultants (0.63 ± 0.29 mSv, p = 0.008).

Discussion

Despite these variations, AMED values remained lower than the annual occupational dose limit of 20 mSv, indicating generally low radiation exposure for anesthesia staff. This study emphasizes the importance of ongoing monitoring and enhanced protective measures to safeguard the health of medical professionals working with radiation.

Evolving Concepts in Cardiac Physiologic Pacing in the Era of Conduction System Pacing

Cardiac physiologic pacing (CPP) has become a well-established therapy for patients with cardiomyopathy (left ventricular ejection fraction <35%) in the presence of a left bundle branch block. In addition, CPP can be highly beneficial in patients with pacing-induced cardiomyopathy and patients with existing cardiomyopathy expected to have a right ventricular pacing burden of >40%. The benefits of CPP with traditional biventricular pacing are only realized if adequate resynchronization can be achieved. However, left ventricular lead implantation can be limited by individual anatomic variation within the coronary venous system and can be adversely affected by underlying abnormal myocardial substrate (i.e., scar tissue), especially if located within the basal lateral wall. In the last 7 years the investigation of conduction system pacing (CSP) and its potential salutary benefits are being realized and have led to a rapid evolution in the field of cardiac resynchronization pacing. However, supportive evidence for CSP for patients eligible for cardiac resynchronization remains limited compared with data available for biventricular cardiac resynchronization, mostly derived from leading CSP investigative centers. In this review, we perform an up-to-date comprehensive review of the available literature on CPP.

Establishment of institutional diagnostic reference level for coronary angiography procedures in Sri Lanka

Amongst many interventional procedures performed in a cardiac catheterisation laboratory, the coronary angiography (CAG) is the most frequently performed cardiac interventional procedure. A diagnostic reference level (DRL) is an effective tool to optimise the radiation exposure to patients and staff whilst maintaining the adequate diagnostic image quality. The aim of the study was to establish institutional DRLs for the CAG procedures performed at a selected private hospital in Colombo, Sri Lanka. A total of 325 CAG procedures were selected for this study from two C-arm machines. The institutional DRLs of cumulative dose length product (DAP) and fluoroscopic time for the CAG procedure were calculated. The established institutional DRL for accumulated DAP and fluoroscopic time are 10 610 mGycm2 and 2.31 min, respectively. As this study conducted at only one institute we recommend to develop national DRLs for mostly performing interventional procedures in Sri Lanka by considering all influencing factors to optimise the patient dose.

Effect of Different Anthropometric Body Indexes on Radiation Exposure in Patients Undergoing Cardiac Catheterisation and Percutaneous Coronary Intervention

BACKGROUND

Patient factors, such as sex and body mass index (BMI), are known to influence patient radiation exposure. Body surface area (BSA) and its association with patient radiation exposure has not been well studied.

METHODS AND RESULTS

We analysed height, weight, BMI and BSA in consecutive patients undergoing cardiac catheterisation and percutaneous coronary intervention (PCI) at a high-volume Australian centre between September 2016 and April 2020 to assess their association with dose-area product (DAP, Gycm2). The mean age of the cohort was 64.5 ± 12.3 years with males comprising 68.8% (n = 8100, 5124 diagnostic cardiac catheterisation cases and 2976 PCI cases). Median male BMI was 28.4 kg/m2 [IQR 25.2-32.1] versus 28.8 kg/m2 [24.7-33.7] for females, p = 0.01. Males had higher BSA (2.0 ± 0.2 m2) than females (1.78 ± 0.2 m2), p = 0.001. Each 0.4 m2 increase in BSA conferred a 1.32x fold change in DAP (95% CI 1.29-1.36, p ≤ 0.001). Each 5 kg/m2 increase in BMI was linked to a 1.13x DAP fold change (1.12-1.14, p ≤ 0.001). Male sex conferred a 1.23x DAP fold change (1.20-1.26, p ≤ 0.001). Multivariable modelling with BMI or BSA explained 14% of DAP variance (R2 0.67 vs. 0.53 for both, p ≤ 0.001).

CONCLUSIONS

BSA is an important anthropometric measure between the sexes and a key predictor of radiation dose and radiation exposure beyond sex, BMI, and weight.

Anthropometric parameters and radiation doses during percutaneous coronary procedures

PURPOSE

Body size is a major determinant of patient's dose during percutaneous coronary interventions (PCI). Body mass index, body surface area (BSA), lean body mass and weight are commonly used estimates for body size. We aim to identify which of these measures and which procedural/clinical characteristics can better predict received dose.

METHODS

Dose area product (DAP, Gycm²), fluoroscopy DAP rate (Gycm²/min), fluoroscopy DAP (Gycm²), cine-angiography DAP (Gycm²), Air Kerma (mGy) were selected as indices of patient radiation dose. Different clinical/procedural variables were analysed in multiple linear regression models with previously mentioned patient radiation dose parameters as end points. The best model for each of them was identified.

RESULTS

Overall 6623 PCI were analysed, median fluoroscopy DAP rate was 35 [IQR 2.7,4.4] Gycm², median total DAP was 62.7 [IQR 38.1,107] Gycm². Among all anthropometric variables, BSA showed the best correlation with all radiation dose parameters considered. Every 1 m² increment in BSA added 4.861 Gycm²/min (95% CI [4.656, 5.067]) to fluoroscopy DAP rate and 164 Gycm² (95% CI [145.3, 182.8]) to total DAP. Height and female sex were significantly associated to a reduction in fluoroscopy DAP rate and total DAP. Coronary angioplasty, diabetes, basal creatinine and the number of treated vessels were associated to higher values.

CONCLUSIONS

Main determinants of patient radiation dose are: BSA, female sex, height and number of treated vessels. In an era of increasing PCI complexity and obesity prevalence, these results can help clinicians tailoring X-ray administration to patient's size.

Laser-Generated Leaky Acoustic Wave Imaging for Interventional Guidewire Guidance

Ultrasound (US) is widely used to visualize both tissue and the positions of surgical instruments in real time during surgery. Previously we proposed a new method to exploit US imaging and laser-generated leaky acoustic waves (LAWs) for needle visualization. Although successful, that method only detects the position of a needle tip, with the location of the entire needle deduced from knowing that the needle is straight. The purpose of the current study was to develop a beamforming-based method for the direct visualization of objects. The approach can be applied to objects with arbitrary shapes, such as the guidewires that are commonly used in interventional guidance. With this method, illumination by a short laser pulse generates photoacoustic waves at the top of the guidewire that propagate down its metal surface. These waves then leak into the surrounding tissue, which can be detected by a US array transducer. The time of flight consists of two parts: 1) the propagation time of the guided waves on the guidewire and 2) the propagation time of the US that leaks into the tissue. In principle, an image of the guidewire can be formed based on array beamforming by taking the propagation time on the metal into consideration. Furthermore, we introduced directional filtering and a matched filter to compress the dispersion signal associated with long propagation times. The results showed that guidewires could be detected at depths of at least 70 mm. The maximum detectable angle was 56.3°. LAW imaging with a 1268-mm-long guidewire was also demonstrated. The proposed method has considerable potential in new clinical applications.

Enhancing the use of computed tomography and cardiac catheterization angiography in Zambia: A project report on a global extension of medical technology in Japan

Cardiovascular disease (CVD) is one of the leading causes of death in adults in Zambia among the non-communicable diseases. The Government of the Republic of Zambia through the Ministry of Health procured Japanese radiological systems, computed tomography, and angiography for the University Teaching Hospitals (UTHs) - Adult in 2015. However, the operation of these diagnostic systems has not been optimal due to lack of a proper maintenance service plan, lack of competent health professionals, and erratic supply of medical consumables. In this study, we report our experiences of providing intensive training to multidisciplinary healthcare teams of the radiology department at UTHs - Adult from 2017 to 2019 to strengthen the quality management system of the radiological equipment so as to provide effective healthcare services. However, the COVID-19 pandemic has had enormous negative impact on essential healthcare. Long-term support through continuous hands-on training must be provided to establish sustainable healthcare services.

Higher patient doses through X-ray imaging procedures

Medical imaging using X-rays has been one of the most popular imaging modalities ever since the discovery of X-rays 125 years ago. With unquestionable benefits, concerns about radiation risks have frequently been raised. Computed tomography (CT) and fluoroscopic guided interventional procedures have the potential to impart higher radiation exposure to patients than radiographic examinations. Despite technological advances, there have been instances of increased doses per procedure mainly because of better diagnostic information in images. However, cumulative dose from multiple procedures is creating new concerns as effective doses >100 mSv are not uncommon. There is a need for action at all levels. Manufacturers must produce equipment that can provide a quality diagnostic image at substantially lesser dose and better implementation of optimization strategies by users. There is an urgent need for the industry to develop CT scanners with sub-mSv radiation dose, a goal that has been lingering. It appears that a new monochromatic X-ray source will lead to replacement of X-ray tubes all over the world in coming years and will lead to a drastic reduction in radiation doses. This innovation will impact all X-ray imaging and will help dose reduction. For interventional procedures, the likely employment of robotic systems in practice may drastically reduce radiation exposures to operators- but patient exposure will still remain an issue. Training needs always need to be emphasized and practiced.

Factors Influencing Fluoroscopy Use During Ureteroscopy at a Residency Training Program

Introduction: Ionizing radiation is used throughout urologic surgery and is known to cause a greater cancer risk with increasing exposure. The International Commission on Radiological Protection states that "it is the control of radiation dose that is important, no matter the source." However, there are few reports on the amount of radiation used by urology residents during ureteroscopy (URS). We present the largest database evaluating fluoroscopy (fluoro) use during URS at a resident training program. Our objective is to assess the amount of fluoro use at varying levels of experience and to identify factors that lead to increased fluoro use. Methods: Retrospective data from 242 URSs performed at two resident training sites were collected. In total, 105 surgeries were done by two attending physicians without and 137 surgeries with residents (Uro1-Uro3). Patient data were collected from the electronic medical record. Statistical analyses included analysis of variance, Spearman correlations, and multiple linear regression (MLR). Results: Comparisons between years 1 and 2 revealed significantly (p < 0.05) decreased fluoro time (20.0 seconds) and operative time (OT) (12.2 minutes) for the year 2 resident. Total OT was significantly (p < 0.05) decreased (11.1 minutes) for attending physicians operating on their own compared with a year 1 resident. Significant (p < 0.05) correlations with fluoro time were demonstrated for OT, stone size, ureteral dilation, ureteral access sheath use, presence of a preoperative stent, resident year, and resident month. OT, ureteral dilation, and a preoperative stent placement were significant predictors of fluoro time on MLR (p < 0.05). Conclusion: Fluoro time during retrograde URS was significantly reduced as residents gained more experience in the operating room. An increase in fluoro time was also associated with ureteral dilation, access sheath use, increasing stone size, and lack of prestenting. With knowledge of these factors, emphasis can be placed on using and teaching techniques that limit radiation exposure.

EVALUATION OF RADIATION DOSE IN DIFFERENT POSITIONS AROUND THE PATIENT TABLE DURING INTERVENTIONAL CARDIOLOGY PROJECTIONS

The aim of the present study was to evaluate the radiation exposure around the patient table as relative to the cardiologist position dose value. The dose rates at eight points presuming staff positions were measured for PA, LAO 30° and RAO 30° radiographic projections, and then normalized to the cardiologist's position dose-rate value. The results show that in PA and RAO 30° projections, the normalized dose rate was higher by 9-22% at the right side of the table at a distance of 50 cm, while it was higher up to 31% at the left side for the same measured points in the LAO 30°. The differences of normalized dose rates for the both table sides were lower and decreased at farther positions. The obtained results correspond to the recommendations of staff radiation protection in Cath-labs with regards to X-ray tube and detector positions.

CONTEMPORARY RADIATION DOSES IN INTERVENTIONAL CARDIOLOGY: A NATIONWIDE STUDY OF PATIENT SKIN DOSES IN FINLAND

In contemporary interventional cardiology, for typical elderly patients, the most severe radiation-related harm to patients can be considered to come from skin exposures. In this paper, maximum local skin doses in cardiological procedures are explored with Gafchromic film dosimetry. Film and reader calibrations and reading were performed at the Secondary Standards Dosimetry Laboratory of the Radiation and Nuclear Safety Authority (STUK), and data were gathered from seven hospitals in Finland. As alert levels for early transient erythema, 200 Gycm2 kerma area product (KAP) and 2000 mGy air kerma levels for transcatheter aortic valve implantations (TAVI) procedures are proposed. The largest doses were measured in TAVI (4158.8 mGy) and percutaneous coronary interventions (PCI) (941.68 mGy). Accuracies of the GE DoseWatch and Siemens CareMonitor skin dose estimates were reasonable, but more results are needed to reliably assess and validate the tools' capabilities and reliabilities. Uncertainty of the Gafchromic dosimetry was estimated as 9.1% for a calibration with seven data points and 19.3% for a calibration with five data points.

The role of a commercial radiation dose index monitoring system in establishing local dose reference levels for fluoroscopically guided invasive cardiac procedures

PURPOSE

The primary goal was to evaluate local dose level for fluoroscopically guided invasive cardiac procedures in a high-volume activity catheterization laboratory, using automatic data registration with minimal impact on operator workload. The secondary goal was to highlight the relationship between dose indices and acquisition parameters, in order to establish an effective strategy for protocols optimization.

METHODS

From September 2016 to December 2018, a dosimetric survey was conducted in the 2 rooms of the catheterization laboratory of our institution. Data collection burden was minimized using a commercial Radiation Dose Index Monitoring System (RDIMs) that analyzes dicom files automatically sent by the x-ray equipment. Data were combined with clinical information extracted from the HIS records reported by the interventional cardiologist. Local dose levels were established for different invasive cardiac procedures.

RESULTS

A total of 3029 procedures performed for 2615 patients were analyzed. Median KAP were 21 Gycm² for invasive coronary angiography (ICA) procedures, 61 Gycm² for percutaneous coronary intervention (PCI) procedures, 59 Gycm² for combined (ICA+PCI) procedures, 87 Gycm² for structural heart intervention (TAVI) procedures. A significant dose reduction (51% for ICA procedures and 58% for PCI procedures) was observed when noise reduction acquisition techniques were applied.

CONCLUSIONS

RDIMs are effective tools in the establishment of local dose level in interventional cardiology, as they mitigate the burden to collect and register extensive dosimetric data and exposure parameters. Systematic review of data support the multi-disciplinary team in the definition of an effective strategy for protocol management and dose optimization.

Assessment of Patient Dose with Special Look at Pediatrics during Cardiovascular Imaging

Background

During interventional cardiology processes, patients especially women and children receive high radiation doses due to their sensitivity.

Objective

In this study, we evaluated a pediatric patient dose separately in those undergone intervention cardiac procedure.

Material and Methods

In this cross sectional study, a public hospital with 252 patients, Entrance Skin Dose (ESD) and Dose-Area Product (DAP) were recorded. Prior to the beginning of fluoroscopic procedure, the chest thickness and Body Mass Index (BMI) of patients were measured. Furthermore, kV, mAs, angle of tube and time of angiography and angioplasty were recorded.

Results

Children ratio to all patients underwent the cardiovascular imaging was 1.8. The means of patients' ESD, DAP and fluoroscopy time were 178.3±17 mGy, 1123.6±11 μGycm² and 281.4±181.2 s, respectively for coronary angiography. The females were 96.8 under 30 years and their dose mean was 276±37 mGy, 368±24 μGycm² for ESD and DAP received, respectively with 376s fluoroscopy time. Mean mAs was 359±34 and kV was 71.23±2.7. Above all, a direct and significant correlation was found between the patients' chest thickness with kV (p=0.037, r = 0.11) and mAs (p<0.001, r = 0.28) variations.

Conclusion

The results demonstrated that the number of children referred to the cardiology department and also the dose rate received by them during this test was higher than the data provided for children in developing countries. Paying attention to the children's perception of high-fluorescence time is necessary in comparison with total angiography time in order to reduce the number of radiation injuries among pediatrics.

Safety and Effectiveness of Neuro-thrombectomy on Single compared to Biplane Angiography Systems

An increasing number of centers not necessarily equipped with biplane (BP) angiosuites are performing mechanical thrombectomy (MT) in acute ischemic stroke patients. We assessed whether MT performed on single-plane (SP) is equivalent in terms of safety, effectiveness, radiation and contrast agent exposure. Consecutive patients treated by MT in four high volume centers between January 2014 and May 2017 were included. Demographic and MT characteristics were assessed and compared between SP and BP. Of 906 patients treated by MT, 576 (64%) were handled on a BP system. After multivariate analysis, contrast load and fluoroscopy duration were significantly lower in the BP group [100vs200mL, relative effect 0.85 (CI: 0.79-0.92), p = 0.0002; 22 vs 27 min, relative effect 0.84 (CI: 0.76-0.93), p = 0.0008, respectively]. There was no difference in recanalization (modified Thrombolysis-In-Cerebral-Infarction 2b-3), good clinical outcome (modified Rankin Scale 0-2), complications rates, procedure duration or radiation exposure. A three-vessel diagnostic angiogram performed prior to MT led to a significant increase in procedure duration (15% increase, p = 0.05), radiation exposure (33% increase, p < 0.0001) and contrast load (125% increase, p < 0.0001). Mechanical neuro-thrombectomy seems equally safe and effective on a single or biplane angiography system despite increased contrast load and fluoroscopy duration on the former.

Immersive Radiation Experience for Interventional Radiology with Virtual Reality Radiation Dose Visualization Using Fast Monte Carlo Dose Estimation

For interventional radiology (IR), understanding the precise dose distribution is crucial to reduce the risks of radiation dermatitis to patients and staff. Visualization of dose distribution is expected to support radiation safety efforts immensely. This report presents techniques for perceiving the dose distribution using virtual reality (VR) technology and for estimating the air dose distribution accurately using Monte Carlo simulation for VR dose visualization. We adopted an earlier reported Monte-Carlo-based estimation system for IR and simulated the dose in a geometrical area resembling an IR room with fluoroscopic conditions. Users of our VR system experienced a simulated air dose distribution in the IR room while the irradiation angle, irradiation timing, and lead shielding were controlled. The estimated air dose was evaluated through comparison with measurements taken using a radiophotoluminescence glass dosimeter. Our dose estimation results were consistent with dosimeter readings, showing a 13.5% average mutual difference. The estimated air dose was visualized in VR: users could view a virtual IR room and walk around in it. Using our VR system, users experienced dose distribution changes dynamically with C-arm rotation. Qualitative tests were conducted to evaluate the workload and usability of our VR system. The perceived overall workload score (18.00) was lower than the scores reported in the literature for medical tasks (50.60) and computer activities (54.00). This VR visualization is expected to open new horizons for understanding dose distributions intuitively, thereby aiding the avoidance of radiation injury.

CONTEMPORARY RADIATION DOSES IN INTERVENTIONAL CARDIOLOGY: A NATIONWIDE STUDY OF PATIENT DOSES IN FINLAND

The amount of interventional procedures such as percutaneous coronary intervention (PCI), transcatheter aortic valve implantation (TAVI), pacemaker implantation (PI) and ablations has increased within the previous decade. Simultaneously, novel fluoroscopy mainframes enable lower radiation doses for patients and operators. Therefore, there is a need to update the existing diagnostic reference levels (DRLs) and propose new ones for common or recently introduced procedures. We sought to assess patient radiation doses in interventional cardiology in a large sample from seven hospitals across Finland between 2014 and 2016. Data were used to set updated national DRLs for coronary angiographies (kerma-air product (KAP) 30 Gycm2) and PCIs (KAP 75 cm2), and novel levels for PIs (KAP 3.5 Gycm2), atrial fibrillation ablation procedures (KAP 25 Gycm2) and TAVI (KAP 90 Gycm2). Tentative KAP values were set for implantations of cardiac resynchronization therapy devices (CRT, KAP 22 Gycm2), electrophysiological treatment of atrioventricular nodal re-entry tachycardia (6 Gycm2) and atrial flutter procedures (KAP 16 Gycm2). The values for TAVI and CRT device implantation are published for the first time on national level. Dose from image acquisition (cine) constitutes the major part of the total dose in coronary and atrial fibrillation ablation procedures. For TAVI, patient weight is a good predictor of patient dose.

Pilot study of the multicentre DISCHARGE Trial: image quality and protocol adherence results of computed tomography and invasive coronary angiography

OBJECTIVE

To implement detailed EU cardiac computed tomography angiography (CCTA) quality criteria in the multicentre DISCHARGE trial (FP72007-2013, EC-GA 603266), we reviewed image quality and adherence to CCTA protocol and to the recommendations of invasive coronary angiography (ICA) in a pilot study.

MATERIALS AND METHODS

From every clinical centre, imaging datasets of three patients per arm were assessed for adherence to the inclusion/exclusion criteria of the pilot study, predefined standards for the CCTA protocol and ICA recommendations, image quality and non-diagnostic (NDX) rate. These parameters were compared via multinomial regression and ANOVA. If a site did not reach the minimum quality level, additional datasets had to be sent before entering into the final accepted database (FADB).

RESULTS

We analysed 226 cases (150 CCTA/76 ICA). The inclusion/exclusion criteria were not met by 6 of the 226 (2.7%) datasets. The predefined standard was not met by 13 of 76 ICA datasets (17.1%). This percentage decreased between the initial CCTA database and the FADB (multinomial regression, 53 of 70 vs 17 of 75 [76%] vs [23%]). The signal-to-noise ratio and contrast-to-noise ratio of the FADB did not improve significantly (ANOVA, p = 0.20; p = 0.09). The CTA NDX rate was reduced, but not significantly (initial CCTA database 15 of 70 [21.4%]) and FADB 9 of 75 [12%]; p = 0.13).

CONCLUSION

We were able to increase conformity to the inclusion/exclusion criteria and CCTA protocol, improve image quality and decrease the CCTA NDX rate by implementing EU CCTA quality criteria and ICA recommendations.

KEY POINTS

• Failure to meet protocol adherence in cardiac CTA was high in the pilot study (77.6%). • Image quality varies between sites and can be improved by feedback given by the core lab. • Conformance with new EU cardiac CT quality criteria might render cardiac CTA findings more consistent and comparable.

Advantage of Steerable Catheter and Haptic Feedback for a 5-DOF Vascular Intervention Robot System

Vascular intervention involves inserting a catheter and guidewire into blood vessels to diagnose and treat a disease in an X-ray environment. In this conventional vascular intervention procedure, the doctor is exposed to considerable radiation. To reduce the exposure, we developed a master–slave robot system. A steerable catheter is employed to shorten the task-time and reduce the contact force applied to the vessel walls during catheter insertion. The steerable catheter helps to select a vascular branch; thus, the radiation exposure time for patients is reduced, and perforation in the patient’s vessel is prevented. Additionally, the robot system employs a haptic function to replicate the physician’s tactile sensing in vascular intervention. In this study, the effectiveness of the steering catheter and haptic function was demonstrated experimentally in comparison with a conventional catheter.

Three-dimensional rotational angiography in congenital heart disease: Present status and evolving future

Three-dimensional rotational angiography (3D-RA) enables volumetric imaging through rotation of the C-arm of an angiographic system and real-time 3D reconstruction during cardiac catheterization procedures. In the field of congenital heart disease (CHD), 3D-RA has gained considerable traction, owing to its capability for enhanced visualization of spatial relationships in complex cardiac morphologies and real time image guidance in an intricate interventional environment. This review provides an overview of the current applications, strengths, and limitations of 3D-RA acquisition in the management of CHD and potential future directions. In addition, issues of dosimetry, radiation exposure, and optimization strategies will be reviewed. Further implementation of 3D-RA will be driven by patient benefits relative to existing 3D imaging capabilities and fusion techniques balanced against radiation exposure.

RADIATION DOSE TO PATIENTS IN CORONARY INTERVENTIONAL PROCEDURES: A SURVEY

The objective of this study was to evaluate dose-area product (DAP) and peak skin dose (PSD) for coronary angiography (CA) and percutaneous coronary intervention (PCI). The DAP and PSD of 300 randomly selected patients who were referred to CA and/or PCI, over a period of 3 months were recorded and analyzed. The mean DAP of 32 Gy cm2 and mean PSD of 412 mGy for CA were lower than 118 Gy cm2 and 857 mGy, respectively, for PCI. The DAP range of 2-84 Gy cm2 for CA and 12-378 mGy for PCI were also established. The maximum value of PSD for PCI procedures reached above the 2 Gy threshold for erythema. However, these values are similar to those available in literature. Periodic surveys may be required to monitor and/or reduce radiation doses in coronary interventional procedures.

Retrospective study of patients radiation dose during cardiac catheterization procedures

OBJECTIVE

Cardiac catheterization procedures provide tremendous benefits to modern healthcare and the benefit derived by the patient should far outweigh the radiation risk associated with a properly optimized procedure. With increasing utilization of such procedures, there is growing concern regarding the magnitude and variations of dose to patients associated with procedure complexity and techniques parameters. Therefore, this study investigated radiation dose to patients from six cardiac catheterization procedures at our facility and suggest possible initial dose values for benchmark for patient radiation dose from these procedures. This initial benchmark data will be used for clinical radiation dose management which is essential for assessing the impact of any quality improvement initiatives in the cardiac catheterization laboratory.

METHODS

We retrospectively analyzed the dose parameters of 1000 patients who underwent various cardiac catheterization procedures: left heart catheterization (LH), percutaneous coronary intervention (PCI), complex PCI, LH with complex PCI, LH with PCI and cardiac resynchronization therapy (CRT) pacemaker in our cardiac catheterization laboratories. Patient's clinical radiation dose data [kerma-area-product (KAP) and air-kerma at the interventional reference point (Ka,r)] and technique parameters (fluoroscopy time, tube potential, current, pulse width and number of cine images) along with demographic information (age, height and weight) were collected from the hospital's RIS (Synapse), Sensis/Syngo Dynamics and Siemens Sensis Stats Manager electronic database. Statistical analysis was performed with the IBM SPSS Modeler v. 18.1 software.

RESULTS

The overall patient median age was 67.0 (range: 26.0-97.0) years and the median body mass index (BMI) was 28.8 (range: 15.9-61.7) kg/m2 . The median KAP for the LH, PCI, LH with complex PCI, complex PCI, LH with PCI and CRT-pacemaker procedures are 44.4 (4.1-203.2), 80.2 (18.9-208.5), 83.7 (48.0-246.1), 113.8 (60.9-284.5), 91.7 (6.0-426.0) and 51.1 (7.0-175.9) Gy-cm2 . The median Ka,r for the LH, PCI, LH with complex PCI, complex PCI, LH with PCI and CRT-pacemaker procedures are 701.0 (35.3-3794.0), 1384.7 (291.7-4021.8), 1607.0 (883.5-4448.3), 2260.2 (867.4-5311.9), 1589.3 (100.2-7237.4) and 463.8 (67.7-1695.9) mGy respectively.

CONCLUSION

We have analyzed patient radiation doses from six commonly used procedures in our cardiac catheterization laboratories and suggested possible initial values for benchmark from these procedures for the fluoroscopy time, KAP and air-kerma at the interventional reference point based on our current practices. Our data compare well with published values reported in the literature by investigators who have also studied patient doses and established benchmark dose levels for their facilities. Procedure-specific benchmark dose data for various groups of patients can provide the motivation for monitoring practices to promote improvements in patient radiation dose optimization in the cardiac catheterization laboratories.

ADVANCES IN KNOWLEDGE

We have investigated local patients' radiation doses and established benchmark radiation data which are essential for assessing the impact of any quality improvement initiatives for radiation dose optimization.

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.

Radiation dose monitoring in pediatric fluoroscopy: comparison of fluoroscopy time and dose-area product thresholds for identifying high-exposure cases

BACKGROUND

Fluoroscopy time has been used as a surrogate for radiation dose monitoring in pediatric fluoroscopy; however it does not account for factors such as magnification or collimation. Dose-area product (DAP) is a more accurate measure of radiation exposure but its dependence on patient weight and body-part thickness is a challenge in children of varying ages.

OBJECTIVE

To determine whether fluoroscopy time and DAP produce concurrent results when they are used to identify high-exposure cases, and to establish radiation dose thresholds for our institution.

MATERIALS AND METHODS

During a 2-year period we prospectively monitored pediatric fluoroscopy studies performed at the Children's Hospital at Montefiore. We recorded study type, fluoroscopy time, DAP, patient age, weight and height. We then calculated 90th percentile fluoroscopy time and DAP thresholds for weight and age.

RESULTS

We evaluated 1,011 cases (453 upper gastrointestinal [UGI] series, 266 voiding cystourethrograms [VCUGs], 120 contrast enemas, 108 speech studies, and 64 esophagrams). Fluoroscopy time demonstrated moderate correlation with DAP (r_s=0.45, P<0.001, Spearman rank). DAP strongly correlated with patient weight (r_s=0.71, P<0.001) and age (r_s=0.70, P<0.001). Concordance of cases exceeding 90th percentile thresholds for fluoroscopy time and DAP were κ=0.27 for UGI series and κ=0.49 for VCUG for weight-based cutoffs, and κ=0.36 for UGI series and κ=0.40 for VCUG for age-based cutoffs.

CONCLUSION

The limited correlation of fluoroscopy time with DAP suggests these methods are not equivalent for dose monitoring. However, the strong correlation of DAP with patient weight and age presents a challenge for establishing DAP thresholds in children, who range widely in size. Despite controlling for weight or age, there was limited overlap of cases exceeding the 90th percentile threshold for fluoroscopy time and DAP. This further reinforces the non-overlapping outcome of these two methods and indicates that fluoroscopy time might be inadequate for dose monitoring.

Validation of a novel stand-alone software tool for image guided cardiac catheter therapy

Comparison of the targeting accuracy of a new software method for MRI-fluoroscopy guided endomyocardial interventions with a clinically available 3D endocardial electromechanical mapping system. The new CARTBox2 software enables therapy target selection based on infarction transmurality and local myocardial wall thickness deduced from preoperative MRI scans. The selected targets are stored in standard DICOM datasets. Fusion of these datasets with live fluoroscopy enables real-time visualization of MRI defined targets during fluoroscopy guided interventions without the need for external hardware. In ten pigs (60–75 kg), late gadolinium enhanced (LGE) MRI scans were performed 4 weeks after a 90-min LAD occlusion. Subsequently, 10–16 targeted fluorescent biomaterial injections were delivered in the infarct border zone (IBZ) using either the NOGA 3D-mapping system or CARTBox2. The primary endpoint was the distance of the injections to the IBZ on histology. Secondary endpoints were total procedure time, fluoroscopy time and dose, and the number of ventricular arrhythmias. The average distance of the injections to the IBZ was similar for CARTBox2 (0.5 ± 3.2 mm) and NOGA (− 0.7 ± 2.2 mm; p = 0.52). Injection procedures with CARTBox2 and NOGA required 69 ± 12 and 60 ± 17 min, respectively (p = 0.36). The required endocardial mapping procedure with NOGA prior to injections, leads to a significantly longer total procedure time (p < 0.001) with NOGA. Fluoroscopy time with NOGA (18.7 ± 11.0 min) was significantly lower than with CARTBox2 (43.4 ± 6.5 min; p = 0.0003). Procedures with CARTBox2 show a trend towards less ventricular arrhythmias compared to NOGA. CARTBox2 is an accurate and fast software-only system to facilitate cardiac catheter therapy based on gold standard MRI imaging and live fluoroscopy.

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.

Diagnostic accuracy of coronary CT angiography performed in 100 consecutive patients with coronary stents using a whole-organ high-definition CT scanner

AIMS

To evaluate image quality, interpretability, diagnostic accuracy and radiation exposure of coronary CT angiography (CCTA) performed with a new scanner equipped with 0.23-mm spatial resolution, new generation iterative reconstruction, 0.28-second gantry rotation time and intra-cycle motion-correction algorithm in consecutive patients with coronary stents, including those with high heart rate (HR) and atrial fibrillation (AF).

MATERIALS AND METHODS

We enrolled 100 consecutive patients (85 males, mean age 65 ± 10 years) with previous coronary stent implantation scheduled for clinically indicated non-emergent invasive coronary angiography (ICA). Image quality, coronary interpretability and diagnostic accuracy vs. ICA were evaluated and the effective dose (ED) was recorded.

RESULTS

Mean HR during the scan was 67 ± 13 bpm. Twenty-six patients had >65 bpm HR during scanning and 13 patients had AF. Overall, image quality was high (Likert = 3.2 ± 0.9). Stent interpretability was 95.8% (184/192 stents). Among 192 stented segments, CCTA correctly identified 22 out of 24 with >50% in-stent restenosis (ISR) (sensitivity 92%). In a stent-based analysis, specificity, positive and negative predictive values and diagnostic accuracy for ISR detection were 91%, 99%, 60% and 91%, respectively. In a patient-based analysis, CCTA diagnostic accuracy was 85%. Overall, mean ED of CCTA was 2.4 ± 1.2 mSv.

CONCLUSIONS

A whole-organ CT scanner was able to evaluate coronary stents with good diagnostic performance and low radiation exposure, also in presence of unfavorable HR and heart rhythm.

TRANSLATIONAL ASPECT

The present study is the first to evaluate the CCTA capability of detecting in-stent restenosis in consecutive patients, including those with high HR and AF, using a recent scanner generation that combines improved spatial and temporal resolution with wide coverage. Using the whole-organ high-definition CT scanner we obtained high quality images of coronary stents with good interpretability and diagnostic accuracy combined with low radiation exposure, even in patients with unfavorable HR or heart rhythm for CCTA evaluation.

C-arm fluoroscopy in orthopaedic surgical practice

The use of C-arm fluoroscopy in intraoperative orthopaedic procedures has become an important tool in modern orthopaedic surgical practice. It enhances the technical proficiency of the surgeon in addition to reducing the morbidity and length of hospital stay of the patient. Despite the documented benefits of this device, there has been a growing concern about the increased radiation exposure to the surgical team. We therefore present the review of the literature on the usefulness of C-arm fluoroscopy, pitfalls in application of the machine as well as the harmful radiation effects and precautionary measures that need to be observed when using the C-arm fluoroscopy in orthopaedic surgical procedures.

Fast skin dose estimation system for interventional radiology

To minimise the radiation dermatitis related to interventional radiology (IR), rapid and accurate dose estimation has been sought for all procedures. We propose a technique for estimating the patient skin dose rapidly and accurately using Monte Carlo (MC) simulation with a graphical processing unit (GPU, GTX 1080; Nvidia Corp.). The skin dose distribution is simulated based on an individual patient's computed tomography (CT) dataset for fluoroscopic conditions after the CT dataset has been segmented into air, water and bone based on pixel values. The skin is assumed to be one layer at the outer surface of the body. Fluoroscopic conditions are obtained from a log file of a fluoroscopic examination. Estimating the absorbed skin dose distribution requires calibration of the dose simulated by our system. For this purpose, a linear function was used to approximate the relation between the simulated dose and the measured dose using radiophotoluminescence (RPL) glass dosimeters in a water-equivalent phantom. Differences of maximum skin dose between our system and the Particle and Heavy Ion Transport code System (PHITS) were as high as 6.1%. The relative statistical error (2 σ) for the simulated dose obtained using our system was ≤3.5%. Using a GPU, the simulation on the chest CT dataset aiming at the heart was within 3.49 s on average: the GPU is 122 times faster than a CPU (Core i7-7700K; Intel Corp.). Our system (using the GPU, the log file, and the CT dataset) estimated the skin dose more rapidly and more accurately than conventional methods.

Impact of Allura Clarity Technology on Radiation Dose Exposure During Left Atrial Appendage Closure

BACKGROUND

To evaluate the impact of the Clarity IQ technology on reducing radiation risk in patients undergoing cardiac interventional radiology (IR) procedures.

MATERIAL/METHODS

Phantom studies were performed with two angiographic systems, FD10 Allura Xper and FD10 Allura Clarity. In the study, we performed left atrial appendage closure. Dosimetric measurements were performed with thermoluminescent dosimeters (TLD) placed inside a CIRS anthropomorphic phantom. Radiation risk was estimated based on the TLD readings and expressed as the dose absorbed by particular organs. The Mann-Whitney U test was carried out to test for significance of differences in the absorbed radiation doses between the techniques.

RESULTS

During left atrial appendage closure, the estimated dose absorbed by particular organs was lower in the case of the FD10 Allura Clarity system in comparison to the Allura Xper. In this procedure, dose reduction for particular organs ranged between 49-86%.

CONCLUSIONS

Application of the FD10 Allura Clarity system resulted in a significant dose reduction, thereby leading to a significant decrease in radiation risk for patients undergoing IR procedures.

Radiation dose in paediatric cardiac catheterisation: A systematic literature review

OBJECTIVES

It is believed that children are more sensitive to ionising radiation than adults. This work reviewed the reported radiation dose estimates for paediatric cardiac catheterisation. A systematic literature review was performed by searching healthcare databases for studies reporting radiation dose using predetermined key words relating to children having cardiac catheterisation. The quality of publications was assessed using relevant Critical Appraisal Skills Programme questions and their reported radiation exposures were evaluated.

KEY FINDINGS

It is only in recent years that larger cohort observations have been undertaken. Although radiation dose from paediatric cardiac catheterisation has decreased in recent years, the literature indicated that it remains varied and potentially substantial.

CONCLUSION

Standardisation of weight categories and procedure types such as those recommended by the PiDRL project could help compare current and future radiation dose estimates.

Reduction of Radiation Risk to Interventional Cardiologists and Patients during Angiography and Coronary Angioplasty

Radiation risk allied to invasive cardiology is relatively high, and protecting both patients and cardiologists is necessary. The aim of this review is to discuss how to better protect patients and cardiologists against radiation exposure. We performed a global search on PubMed, Science Direct, and Scopus databases via keywords of "interventional cardiologist", "patient", "radiation", and "exposure" and then performed an overview of the main strategies for risk reduction among interventional cardiologists and exposed patients. The 1st line for protection is awareness of both radiation risk factors and exposure doses and how to manage and minimize exposure levels. In conclusion, radiation-attenuating techniques can effectively reduce occupational/treatment radiation exposure to both operators and patients in cardiology interventions.

PATIENT DOSIMETRY DURING INTERVENTIONAL CARDIAC PROCEDURES IN A DEDICATED CATHETERIZATION LABORATORY

Cardiac interventions often result in high radiation dose to patient's skin, so a reliable indicator in terms of a commonly used dose descriptor is required to monitor skin exposures. In the present study, Gafchromic XR-RV3 film was used to measure the peak skin dose (PSD) during 40 coronary angiography (CA) and 50 percutaneous transluminal coronary angioplasty (PTCA) procedures. Corresponding values of kerma-area product (PKA), fluoroscopy time (FT) and reference air-kerma (Ka,r) were recorded and correlated with PSD. Doses to patient's eyes and thyroid were also measured by using thermoluminescent dosimeters (TLDs) during PTCA procedures. The average dose to thyroid was about six times higher than the average dose to eyes. The mean values of PSD, PKA and FT were 1140 mGy, 97 Gy cm2 and 15.7 min for PTCA and 290 mGy, 21.1 Gy cm2 and 2.4 min for CA procedures, respectively. One in seven patients of PTCA procedure received PSD >2 Gy. With respect to FT, PKA may be used as a better predictor of skin exposures because the correlation of PSD with PKA was found better than with FT for both CA and PTCA procedures.

PEDIATRIC RADIATION DOSE DURING CARDIAC CATHETERIZATION PROCEDURES IN SUDAN

Children are more radio sensitive than adult. This study aims to assess radiation doses and the associated hazards to pediatric during cardiac catheterization procedures. Radiation dose for 112 patients was estimated in the biggest cardiac center in Sudan. The median KAP in Gy cm2, CK in mGy, number of frames and fluoroscopy time in minutes were (4.6, 29.0, 340.4, 13.5) and (6.0, 35.0, 318, 9.8) for the diagnostic and therapeutic cardiac procedures, respectively. The median (KAP in Gy cm2, effective dose in mSv) for different age groups in the intervals of less than 1 year, 1-<5 years, 5-<10 years and 10-15 years old were (2.2, 4.4), (2.5, 5.0), (4.2, 5.1) and (8.5, 4.1) respectively. Including all the procedures using the multiplicative model of ICRP 60, the mean attributable lifetime risk for stochastic effect was 0.08 and 0.05% for girls and boys, respectively. Training is needed to raise staff awareness about radiation protection.

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.