Radiation exposure to patients during endoscopic retrograde cholangiopancreatography: A multicentre study in Finland

Impact of equipment technology on reference levels in fluoroscopy-guided gastrointestinal procedures

OBJECTIVES

To evaluate the effect of equipment technology on reference point air kerma (Ka,r), air kerma-area product (PKA), and fluoroscopic time for fluoroscopically-guided gastrointestinal endoscopic procedures and establish benchmark levels.

METHODS

This retrospective study included the consecutive patients who underwent fluoroscopically-guided gastrointestinal endoscopic procedures from May 2016 to August 2023 at a tertiary care hospital in the U.S. Fluoroscopic systems included (a) Omega CS-50 e-View, (b) GE Precision 500D, and (c) Siemens Cios Alpha. Radiation dose was analyzed for four procedure types of endoscopic retrograde biliary, pancreas, biliary and pancreas combined, and other guidance. Median and 75th percentile values were computed using software package R (version 4.0.5, R Foundation).

RESULTS

This large study analyzed 9,459 gastrointestinal endoscopic procedures. Among four procedure types, median Ka,r was 108.8-433.2 mGy (a), 70-272 mGy (b), and 22-55.1 mGy (c). Median PKA was 20.9-49.5 Gy∙cm2 (a), 13.4-39.7 Gy∙cm2 (b), and 8.91-20.9 Gy∙cm2 (c). Median fluoroscopic time was 2.8-8.1 min (a), 3.6-9.2 min (b), and 2.9-9.4 min (c). Their median value ratio (a:b:c) was 8.5:4.8:1 (Ka,r), 2.7:2.1:1 (PKA), and 1.0:1.1:1 (fluoroscopic time). Median value and 75th percentile are presented for Ka,r, PKA, and fluoroscopic time for each procedure type, which can function as benchmark for comparison for dose optimization studies.

CONCLUSION

This study shows manifold variation in doses (Ka,r and PKA) among three fluoroscopic equipment types and provides local reference levels (50th and 75th percentiles) for four gastrointestinal endoscopic procedure types. Besides procedure type, imaging technology should be considered for establishing diagnostic reference level.

SUMMARY

With manifold (2 to 12 times) variation in doses observed in this study among 3 machines, we recommend development of technology-based diagnostic reference levels for gastrointestinal endoscopic procedures.

Fundamental study on diagnostic reference level quantities for endoscopic retrograde cholangiopancreatography using a C-arm fluoroscopy system

The diagnostic reference level (DRL) is an effective tool for optimising protection in medical exposures to patients. However regarding air kerma at the patient entrance reference point (Ka,r), one of the DRL quantities for endoscopic retrograde cholangiopancreatography (ERCP), manufacturers use a variety of the International Electrotechnical Commission and their own specific definitions of the reference point. The research question for this study was whetherKa,ris appropriate as a DRL quantity for ERCP. The purpose of this study was to evaluate the difference betweenKa,rand air kerma incident on the patient's skin surface (Ka,e) at the different height of the patient couch for a C-arm system. Fluoroscopy and radiography were performed using a C-arm system (Ultimax-i, Canon Medical Systems, Japan) and a over-couch tube system (CUREVISTA Open, Fujifilm Healthcare, Japan).Ka,ewas measured by an ion chamber placed on the entrance surface of the phantom. Kerma-area product (PKA) andKa,rwere measured by a built-inPKAmeter and displayed on the fluoroscopy system.Ka,edecreased whileKa,rincreased as the patient couch moved away from the focal spot. The uncertainty of theKa,e/Ka,rratio due to the different height of the patient couch was estimated to be 75%-94%.Ka,rmay not accurately representKa,e.PKAwas a robust DRL quantity that was independent of the patient couch height. We cautioned against optimising patient doses in ERCP with DRLs set in terms ofKa,rwithout considering the patient couch height of the C-arm system. Therefore, we recommend thatKa,ris an inappropriate DRL quantity in ERCP using the C-arm system.

Attitudes to radiation safety and cholangiogram interpretation in endoscopic retrograde cholangiopancreatography (ERCP): a UK survey

BACKGROUND

Fluoroscopy during endoscopic retrograde cholangiopancreatography (ERCP) exposes staff and patients to potentially harmful ionizing radiation. We performed a UK survey to explore trainee and trainer attitudes to radiation protection and cholangiogram interpretation in ERCP.

METHODS

An electronic 10-point survey was prospectively distributed to endoscopy unit leads, training programme directors between October and November 2019. Only UK-based ERCP trainees and trainers with hands-on procedural exposure were eligible for the survey.

RESULTS

The survey was completed by 107 respondents (58 trainees and 49 trainers), with an estimated overall response rate of 46%. Overall, 49% of respondents were up to date with their radiation protection course, 38% were aware of European Basic safety standards directive (BSSD), 38% wore radiation protection goggles, and 40% were aware of the average radiation screening dose per ERCP procedure. Compared with trainers, trainees were less likely to routinely wear thyroid protection shields (76% vs 92%; p=0.028), have awareness of the BSSD (20% vs 49%; p=0.037) or know their average procedural radiation dosages (21% vs 63%; p<0.001). With regard to cholangiogram interpretation, only 26% had received formal training, with 97% of trainees expressing a desire for further training.

CONCLUSION

This survey highlights a relative complacency in safety attitudes to radiation protection during ERCP. These data provide impetus to improve training and quality assurance in radiation protection, which should be regarded as a mandatory safety aspect prior to commencing hands-on ERCP training.

Management of difficult bile duct stones and indeterminate bile duct structures: Reduced ERCP radiation exposure with adjunct use of digital single-operator cholangioscopy

INTRODUCTION

Endoscopic Retrograde Cholangio-Pancreatography (ERCP) is an well-established endoscopic procedure for the management of biliary diseases. The use of fluoroscopy during ERCP has often raised concerns regarding potential risks from radiation exposure, particularly in complex cases. We investigated whether a new digital single-operator cholangioscopy (D-SOC) system, used adjunctively to ERCP, actually reduces patient radiation exposure.

MATERIALS AND METHODS

We retrospectively analyzed a prospective database (April 2016 to October 2018) including consecutive patients who underwent successful management of difficult-to-treat biliary stones or indeterminate biliary strictures by using either conventional ERCP (ERCP cohort) or ERCP in conjunction with D-SOC (ERCP/D-SOC cohort). The overall patient radiation exposure outcomes were compared in terms of Kerma Area Product (KAP), Fluoroscopy time (T) and the total number of films (F).

RESULTS

Overall, 47 patients (mean 71.8 years, 59.6% males) were included (ERCP cohort = 29, ERCP/D-SOC cohort = 18), referred either for difficult bile duct stones (n = 36) or indeterminate biliary strictures (n = 11). The median KAP, T and F in the ERCP/D-SOC cohort were 12.3 Gycm², 3.7 min and 4 films respectively, compared with 52.1 Gycm², 8.4 min, and 5 films respectively in the ERCP cohort. Statistically significant differences (P = 0.0001) were found for KAP and T.

CONCLUSIONS

Adjunct use of a digital cholangioscopy platform appears to significantly reduce radiation exposure in patients undergoing ERCP for the management of difficult bile stones or indeterminate biliary strictures.

Patient radiation dose and fluoroscopy time during ERCP: a single-center, retrospective study of influencing factors

OBJECTIVES

Recently, both the number and the complexity with associated increased technical difficulty of therapeutic ERCP procedures have significantly increased resulting in longer procedural and fluoroscopy times. During ERCP, the patient is exposed to ionizing radiation and the consequent radiation dose depends on multiple factors. The aim of this study was to identify factors affecting fluoroscopy time and radiation dose in patients undergoing ERCP.

MATERIALS AND METHODS

Data related to patient demographics, procedural characteristics and radiation exposure in ERCP procedures (n = 638) performed between August 2013 and August 2015 was retrospectively reviewed and analyzed. Statistically significant factors identified by univariate analyses were included in multivariate analysis with fluoroscopy time (FT) and dose area product (DAP) as dependent variables. Effective dose (ED) was estimated from DAP measurements using conversion coefficient.

RESULTS

The factors independently associated with increased DAP during ERCP were age, gender, radiographer, complexity level of ERCP, cannulation difficulty grade, bile duct injury and biliary stent placement. In multivariate analysis the endoscopist, the complexity level of ERCP, cannulation difficulty grade, pancreatic duct leakage, bile duct dilatation and brushing were identified as predictors for a longer FT. The mean DAP, FT, number of acquired images and ED for all ERCP procedures were 2.33 Gy·cm², 1.84 min, 3 and 0.61 mSv, respectively.

CONCLUSIONS

Multiple factors had an effect on DAP and FT in ERCP. The awareness of these factors may help to predict possible prolonged procedures causing a higher radiation dose to the patient and thus facilitate the use of appropriate precautions.

Patient Radiation Doses in Therapeutic Endoscopic Retrograde Cholangiopancreatography in Patras and the Key Role of the Operator

The patient radiation doses, in conjunction with the operator experience, in therapeutic endoscopic retrograde cholangiopancreatography (ERCP) procedures, performed in our hospital, were obtained. Ninety-six patients participated in the study and were divided into 3 groups, based on the operator experience. The dosemetric indices, fluoroscopy time (FT), cumulative dose (Ka,r) and air kerma-area product (PKA), were collected. For the total and weight banding group the third quartile values of the distribution of FT, Ka,r and PKA were 2.90 and 2.92 min, 6.89 and 6.93 mGy and 1.84 and 1.85 Gycm2, respectively, and were comparative or significantly lower than the corresponding values previously reported. Taking as a criterion the operator, the differences in the patient radiation doses were statistically significant, with the highest dose recorded for the operator of the lowest experience degree. The values obtained could contribute in establishing local and national diagnostic reference levels and in optimising ERCP procedure.

OPTIMISATION OF PATIENT DOSE AND IMAGE QUALITY IN ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY: A PHANTOM-BASED EVALUATION

A phantom-based study is presented aiming to optimise patient dose and image quality (IQ) in endoscopic retrograde cholangiopancreatography procedures, utilising a fluoroscopy system equipped with a flat panel detector. The patient thickness was simulated with various polymethyl methacrylate slabs, whilst IQ was evaluated using the Leeds test object. The main factors evaluated were phantom thickness, distance between phantom and detector, field of view and pulse rate. For all these factors, the dosemetric indices, entrance surface air kerma (ESAK) rate and ESAK per pulse, as well as the IQ parameters, signal-to-noise ratio and high contrast spatial resolution, were measured. Based on these measurements, the figure of merit (FOM) was estimated. The FOM and ESAK rate values indicated the optimum combination of the factors evaluated which could provide adequate clinical information, assuring minimum patient dose.

THE ESTABLISHMENT OF LOCAL DIAGNOSTIC REFERENCE LEVELS IN ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY: A PRACTICAL TOOL FOR THE OPTIMISATION AND FOR QUALITY ASSURANCE MANAGEMENT

Fluoroscopic procedures are an area of special concern in relation to radiation protection. The aim of this study was to describe the current level of patient radiation doses in endoscopic retrograde cholangiopancreatography (ERCP) collected from a single centre, as well as to establish and review local diagnostic reference levels (DRLs) in ERCP. A total of 100 patients' radiation doses in ERCP were recorded, and the third-quartile method was adopted to establish local DRLs for ERCP. The mean dose area product (DAP) was 2.05 Gy cm2, fluoroscopy time (FT) 1.7 min and the number of images was 3. The proposed local DRLs for ERCP were 3.00 Gy cm2 and 3.0 min. Local DRLs were reviewed in a sample of 25 patients 5 y after they had been established. In reviewing data, the averages of DAP and FT were below the local DRLs. Local DRLs help in the optimisation process of fluoroscopic procedures and guides to a good clinical practice.

PATIENT DOSE DURING THERAPEUTIC ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY PROCEDURE

Endoscopic retrograde cholangiopancreatography (ERCP) is a standard technique for the diagnosis and treatment of disorders of the pancreas or bile ducts. The aim of this study was the measurement of the radiation dose to patients during therapeutic ERCP procedures, in order to estimate the patient effective dose (ED). Fifteen patients were studied using a fluoroscopy system equipped with automatic brightness control and pulse fluoroscopy mode. Fluoroscopy time (FT), cumulative dose (Ka,r) and air kerma-area product (PKA) were collected for ERCP procedures. The ED was calculated from PKA values. The FT was ranged from 0.68 to 5.57 min, with the mean value of 2.50 min; the Ka,r was ranged from 2.22 to 19.10 mGy, with the mean value of 7.71 mGy; and the PKA was ranged between 0.59 and 5.10 Gycm2, with the mean value of 2.03 Gycm2. The ED ranged from 0.11 to 0.97 mSv, whilst the mean and median ED values were 0.39 and 0.32 mSv, respectively. FT and radiation dose to the patients were either comparative or significantly lower than those previously reported.