Diagnostic Reference Levels for Fluoroscopy-guided Gastrointestinal Procedures in Japan from the REX-GI Study: A Nationwide Multicentre Prospective Observational Study

Location of endoscopic retrograde cholangiopancreatography impacts fluoroscopy time: a multi-institutional retrospective study at tertiary academic centers

BACKGROUND

Endoscopic retrograde cholangiopancreatography (ERCP) is important in the management of pancreatobiliary diseases and requires fluoroscopy resulting in radiation exposure to those involved. ERCP is performed in different hospital settings such as the endoscopy unit (EU), radiology suite (RS), and operating room (OR) depending on numerous factors. Our study examines the differences in duration of fluoroscopy time (FT) as a surrogate for radiation dosages between multiple unique settings.

METHODS

A retrospective cohort analysis at multiple tertiary academic centers was performed on 3251 ERCPs performed between April 2015 to November 2021. FT was compared between multiple locations, between different fluoroscopy device operators, and between normal working hours versus after hours.

RESULTS

Of the 3228 included patients, 54.8% (n = 1768) patients had an exam in the EU, 37.9% (n = 1223) RS or 7.3% (n = 237) or OR respectively. The average FT in the EU, RS, and OR was 6.0 min, 3.5 min, and 4.1 min respectively. The average FT of the EU was significantly more than the RS, OR, and RS and OR together. The average FT of the cases in the OR was significantly less than cases done outside of the OR (5.0 min). FT during working hours (5.0 min) was significantly longer than FT outside of working hours (3.3 min).

CONCLUSIONS

FT in the EU was longer than in the OR and RS. Locations in which ERCPs were performed by the endoscopist had a longer average FT than those with technician-controlled fluoroscopy.

The effectiveness of a body positioning device for controlling patient movement and additional sedative use during endoscopic retrograde cholangiopancreatography: A retrospective analysis

Background

Endoscopic retrograde cholangiopancreatography requires precise body movement control for procedural safety and efficiency. Sedatives are commonly used but pose risks, especially in elderly patients. This study evaluated the effectiveness of the Medo V-Fix device in controlling patient movement during endoscopic retrograde cholangiopancreatography.

Methods

Of 1723 endoscopic retrograde cholangiopancreatography procedures performed between January 2021 and March 2024, 1,528 were analyzed after excluding cases with missing data. Patients were divided into two groups, the device group (n = 697) and the nondevice group (n = 831). The groups were compared with respect to body movement control, additional sedative administration, sedation-related complications, and procedure discontinuation.

Results

Baseline characteristics were similar between the groups. Body movement control was better with the device (good, 65.7%; poor, 24.0%; and very poor, 10.3%) than without it (good, 48.1%; poor, 30.7%; and very poor, 21.2%; p < 0.0001). The device reduced the need for manual assistance and additional sedatives. Fewer patients in the device group (9.5% vs. 15.6%, p = 0.0003) required an additional thiopental dose, and the dose was lower (4.5 mg vs. 6 mg, p = 0.0015). No procedure discontinuation occurred in the device group, whereas five discontinuations occurred in the nondevice group. Although hypoxemia was more frequent in the device group (14.5% vs. 8.8%, p = 0.0005), no severe adverse events occurred.

Conclusions

The Medo V-Fix device significantly improved body movement control and reduced the need for additional doses of sedatives and manual intervention. Despite a higher incidence of mild hypoxemia, these events were appropriately managed with routine monitoring, indicating that the device increases procedural safety and efficiency.

Radiation Exposure with Self-Expandable Metallic Stent versus Transanal Decompression Tube for Malignant Colorectal Obstruction: A Post Hoc Propensity Score Matched Analysis

Background: Although several reports have compared the outcomes of self-expandable metallic stent (SEMSs) and transanal decompression tube (TDT) placement for malignant colorectal obstruction (MCO), few studies have compared the radiation exposure (RE) associated with these two procedures. Consequently, we aimed to compare the RE of SEMS and TDT placements for MCO using propensity score matching (PSM) in a multi-center, prospective observational study. Methods: This study investigated the clinical data of 236 patients who underwent SEMS or TDT placement. The air kerma at the patient entrance reference point (Ka,r: mGy) and air kerma-area product (PKA; Gycm2) were measured and compared between SEMS and TDT groups after PSM. Results: After PSM, 61 patients were identified in each group. The median Ka,r in the SEMS group was significantly greater than that in the TDT group (77.4 vs. 55.6 mGy; p = 0.025) across the entire cohort. With respect to subgroup analyses by location, in the rectum, the median Ka, r and PKA were significantly greater in the SEMS group than in the TDT group (172.9 vs. 34.6 mGy; p = 0.001; and 46.0 vs. 18.1 Gycm2; p = 0.006, respectively). However, in the colon, the RE parameters did not significantly differ between the two groups. Conclusions: TDT might be a more suitable option for decompression in patients with malignant rectal obstruction due to its lower RE and technical advantages. Conversely, SEMS placement is recommended as the first decompression method to treat malignant colonic obstruction, in line with the current guidelines.

Managing radiation safety and protection in gastroenterology in Japan: insights from the REX-GI study

Fluoroscopy-guided gastrointestinal procedures, including gastrointestinal stenting, balloon-assisted endoscopy (BAE), endoscopic retrograde cholangiopancreatography (ERCP), and endoscopic ultrasound (EUS), are essential for diagnosis and treatment in gastroenterology. Such procedures involve radiation exposure that necessitates strict safety measures to protect patients, doctors, and medical staff. The April 2020 update to Japan's Ionizing Radiation Injury Prevention Regulations for occupational exposure reduced the lens exposure dose limit to approximately one-seventh of its previous level. This change highlights the need for improved safety protocols. Without adaptation, the sustainability of fluoroscopy-based endoscopic techniques could be at risk due to the potential to exceed these new limits. This review examines the current state of medical radiation exposure in the field of gastroenterology in Japan and discusses the findings of the REX-GI study.

Effect of radioprotective curtain length on the scattered dose rate distribution and endoscopist eye lens dose with an over-couch fluoroscopy system

Sufficient dose reduction may not be achieved if radioprotective curtains are folded. This study aimed to evaluate the scattered dose rate distribution and physician eye lens dose at different curtain lengths. Using an over-couch fluoroscopy system, dH*(10)/dt was measured using a survey meter 150 cm from the floor at 29 positions in the examination room when the curtain lengths were 0% (no curtain), 50%, 75%, and 100%. The absorbed dose rates in the air at the positions of endoscopist and assistant were calculated using a Monte Carlo simulation by varying the curtain length from 0 to 100%. The air kerma was measured by 10 min fluoroscopy using optically stimulated luminescence dosimeters at the eye surfaces of the endoscopist phantom and the outside and inside of the radioprotective goggles. At curtain lengths of 50%, 75%, and 100%, the ratios of dH*(10)/dt relative to 0% ranged from 80.8 to 104.1%, 10.5 to 61.0%, and 11.8 to 24.8%, respectively. In the simulation, the absorbed dose rates at the endoscopist's and assistant's positions changed rapidly between 55 and 75% and 65% and 80% of the curtain length, respectively. At the 0%, 50%, 75%, and 100% curtain lengths, the air kerma at the left eye surface of the endoscopist phantom was 237 ± 29, 271 ± 30, 37.7 ± 7.5, and 33.5 ± 6.1 μGy, respectively. Therefore, a curtain length of 75% or greater is required to achieve a sufficient eye lens dose reduction effect at the position of the endoscopist.

Technical note: Workload and transmission data for mobile C-arm fluoroscopy in gastrointestinal endoscopy

BACKGROUND

Mobile C-arms may be used in fixed locations, and it is recommended that qualified experts evaluate structural shielding.

PURPOSE

To assess clinical workload distributions for mobile C-arms used in gastrointestinal endoscopy and determine the Archer equation parameters for the C-arm beam spectra.

METHODS

Consecutive (30 months) gastrointestinal endoscopic procedures on two Cios Alpha systems (Siemens) were retrospectively analyzed. X-ray tube voltage, tube current-time product, reference point air kerma (Ka,r), air kerma-area product (PKA), and fluoroscopic time were examined. The primary beam half-value layer (HVL) was measured with an ionization chamber and aluminum 1100 plates. Stray radiation fraction at 1 m from a scattering source (ACR R/F phantom) was directly measured. Monte Carlo (Geant4) simulation was performed to calculate the transmission of broad X-ray beams through lead, concrete, gypsum, and steel, with X-ray HVLs matching those of the C-arm X-ray beam. The transmission data were fitted to the Archer equation.

RESULTS

The number of procedures (3509) was equivalent to 13.48 procedures per room per week. Dose quantities were 54.8 mGy (Ka,r), 18.3 Gy∙cm2 (PKA), and 7.8 min (fluoroscopic time) per procedure. X-ray beam irradiation events were recorded for 2906 (82.8%) procedures with 160,009 events, whose mA-minute weighted tube voltage was 91.0 kV and the workload was 0.68 mA-minute per procedure. The two rooms had a significant difference in the number of procedures per week, 17.3 (29) [mean (maximum)] and 9.6 (16), respectively. The stray radiation fraction was 9.7×10-4 (80 kV) and 1.25×10-3 (120 kV). Transmission fitting parameters were provided for the tube voltage (on average, 90 kV; high end, 120 kV) of the C-arm.

CONCLUSIONS

This work provides workload and transmission data for mobile C-arm fluoroscopy in gastrointestinal endoscopy, which indicates a need for structural shielding evaluation of the procedure rooms.

Feasibility and safety of intraoperative bile duct clearance by antegrade transcystic balloon sphincteroplasty: A prospective observational pilot study

BACKGROUND

Concomitant cholecystolithiasis and choledocholithiasis are common. Standard treatments are endoscopic retrograde cholangiography (ERC) followed by cholecystectomy or laparoendoscopic rendezvous. Endoscopic retrograde cholangiography has drawbacks, such as post-ERC pancreatitis or bleeding, and potentially more than one intervention is required to address common bile duct (CBD) stones. Safety and feasibility of an intraoperative antegrade transcystic single-stage approach during cholecystectomy with balloon sphincteroplasty and pushing of stones to the duodenum has not been evaluated prospectively. The aim of this pilot study was to evaluate this procedure regarding safety, feasibility, and stone clearance rate.

METHODS

Prospective single-center intervention study (SUPER Reporting-Guideline). Main inclusion criterion was confirmed choledocholithiasis (stones ≤6 mm) at intraoperative cholangiography. Success of the procedure was defined as CBD stone clearance at intraoperative control cholangiography, absence of symptoms and no elevated cholestasis parameters at 6 weeks follow-up. Simon's two-stage design was used to determine sample size.

RESULTS

From January 2021 to April 2022, a total of 57 patients fulfilled the final inclusion criteria and were included. Mild pancreatitis or cholangitis were present upon admission in 15 (26%) and 15 (26%) patients, respectively. Median number of CBD-stones was 1 (1-6). Median stone diameter was 4 mm (0.1-6 mm). Common bile duct stone clearance was achieved in 54 patients (94%). The main reason for failed CBD clearance was the inability to push the guidewire along the biliary stone into the duodenum. Median intervention time was 28 minutes (14-129 minutes). While there was no postoperative pancreatitis, two patients (3.5%) had asymptomatic hyperlipasemia 4 hours postoperatively.

CONCLUSION

Intraoperative CBD stone clearance by antegrade balloon sphincteroplasty appears to be safe and highly feasible. Its overall superiority to the current standards warrants evaluation by a randomized controlled trial.

LEVEL OF EVIDENCE

Therapeutic/Care Management, Level V.

Patient Radiation Exposure during Enteroscopy-Assisted Endoscopic Retrograde Cholangiopancreatography in Surgically Altered Anatomy (with Video)

BACKGROUND

Fluoroscopy must be used cautiously during endoscopic retrograde cholangiopancreatography (ERCP). Radiation exposure data in patients with surgically altered anatomy undergoing enteroscopy-assisted ERCP (EA-ERCP) are scarce.

METHODS

34 consecutive EA-ERCP procedures were compared with 68 conventional ERCP (C-ERCP) procedures. Patient and procedure characteristics and radiation data were collected.

RESULTS

Surgical reconstructions were gastrojejunostomy, Roux-en-Y hepaticojejunostomy, Roux-en-Y total gastrectomy, Roux-en-Y gastric bypass and Whipple's duodenopancreatectomy. Procedures were restricted to biliary indications. Mean fluoroscopy time was comparable in both groups (370 ± 30 s EA-ERCP vs. 393 ± 40 s C-ERCP, p = 0.7074), whereas total mean radiation dose was lower in EA-ERCP (83 ± 6 mGy) compared to C-ERCP (110 ± 11 mGy, p = 0.0491) and dose area product (DAP) was higher in EA-ERCP (2216 ± 173 µGy*m2) compared to C-ERCP (1600 ± 117 µGy*m2, p = 0.0038), as was total procedure time (77 ± 5 min vs. 39 ± 3 min, p < 0.0001). Enteroscope insertion to reach the bile duct during EA-ERCP took 28 ± 4 min, ranging from 4 to 90 min. These results indicate that C-ERCP procedures are generally more complex, needing magnified fluoroscopy, whereas EA-ERCP procedures take more time for enteroscope insertion under wide field fluoroscopic guidance (increased DAP) with less complex ERCP manipulation (lower total radiation dose).

CONCLUSIONS

Radiation exposure during EA-ERCP in surgically altered anatomy is different as compared to C-ERCP. EA-ERCP takes longer with a higher DAP because of the enteroscope insertion, but with lower total radiation dose because these ERCP procedures are usually less complex.

Medical radiation exposure during gastrointestinal enteral metallic stent placement: Post hoc analysis of the REX-GI study

BACKGROUND AND AIM

Recently, the use of various endoscopic procedures performed under X-ray fluoroscopy guidance has increased. With the popularization of such procedures, diagnostic reference levels (DRLs) have been widely accepted as the global standard for various procedures with ionizing radiation. The Radiation Exposure from Gastrointestinal Fluoroscopic Procedures (REX-GI) study aimed to prospectively collect actual radiation exposure (RE) data and establish DRLs in gastrointestinal endoscopy units. In this post hoc analysis of the REX-GI study, we established DRLs for each disease site by analyzing cases of gastrointestinal enteral metallic stent placement.

METHODS

The REX-GI study was a multicenter, prospective observational study conducted to collect actual RE data during gastrointestinal enteral metallic stent placement. To establish DRL values for three disease sites, namely the esophagus, gastroduodenum, and colon, we examined fluoroscopy time (FT; min), number of X-ray images, air kerma at the patient entrance reference point (K a,r; mGy), and the air kerma-area product (P KA; Gy cm2) during enteral metallic stent placement.

RESULTS

Five-hundred and twenty-three stenting procedures were performed. The DRL values of FT (min) and the number of X-ray images for the esophagus/gastroduodenum/colon were 9/16/18 min and 9/15/11 min, respectively. Furthermore, the DRL values of K a,r and P KA for each disease site were 43.3/120/124 mGy and 10.3/36.6/48.4 Gy cm2, respectively. Among the procedures, esophageal stents were significantly associated with the lowest values (P < 0.001).

CONCLUSION

The characteristics of RE vary according to disease site among gastrointestinal enteral metallic stent placements. Thus, it is desirable to set DRL values based on the disease site.

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.

ERCP-related adverse events: incidence, mechanisms, risk factors, prevention, and management

INTRODUCTION

Endoscopic retrograde cholangiopancreatography (ERCP) is a commonly performed procedure for pancreaticobiliary disease. While ERCP is highly effective, it is also associated with the highest adverse event (AE) rates of all commonly performed endoscopic procedures. Thus, it is critical that endoscopists and caregivers of patients undergoing ERCP have clear understandings of ERCP-related AEs.

AREAS COVERED

This narrative review provides a comprehensive overview of the available evidence on ERCP-related AEs. For the purposes of this review, we subdivide the presentation of each ERCP-related AE according to the following clinically relevant domains: definitions and incidence, proposed mechanisms, risk factors, prevention, and recognition and management. The evidence informing this review was derived in part from a search of the electronic databases PubMed, Embase, and Cochrane, performed on 1 May 20231 May 2023.

EXPERT OPINION

Knowledge of ERCP-related AEs is critical not only given potential improvements in peri-procedural quality and related care that can ensue but also given the importance of reviewing these considerations with patients during informed consent. The ERCP community and researchers should aim to apply standardized definitions of AEs. Evidence-based knowledge of ERCP risk factors should inform patient care decisions during training and beyond.

Radiation dose and factors related to exceeding the diagnostic reference level in 496 transnasal ileus tube placement procedures from the REX-GI study

OBJECTIVE

We aimed to examine the factors contributing to radiation exposure exceeding the DRL of the transnasal ileus tube placement in this post hoc analysis from the cohort of the REX-GI study.

METHODS

Patients with transnasal ileus tubes were enrolled in the rex-gi study from may 2019 to december 2020. We investigated the endoscope insertion time (min), procedure time (min), tube insertion length (cm), fluoroscopy time (FT: min), air kerma at the patient entrance reference point (Ka.r: mGy), and air kerma-area product (PKA: Gycm2). The third quartile value of the PKA value was calculated as the diagnostic reference level (DRL) value. We explored the factors associated with radiation exposure exceeding the DRL.

RESULTS

In the REX-GI study, 496 patients who underwent transnasal ileus tube placement were enrolled. The median age of the patients was 71 years. The median endoscopy insertion time, procedure time, and tube insertion length were 6 min, 20 min, and 170 cm, respectively. The third quartile/median FT, Ka.r, and PKA were 18/11.9 min, 99.2/54.4 mGy, and 46.9/28 Gycm2, respectively. The third quartile value of PKA (47 Gycm2) was set as the DRL value. There were differences in distribution by the hospital. Compared with procedures under the DRL, the FT (19 vs 10 min), procedure time (25 vs 18 min), and tube insertion length (185 vs 165 cm) were significantly longer for procedures above the DRL.

CONCLUSION

We report the DRL for transnasal ileus tube placement in Japan. A longer procedure time and tube insertion length may be associated with DRL exceedance.

ADVANCES IN KNOWLEDGE

Transnasal ileus tube placement under fluoroscopy guidance is a standard clinical procedure for bowel obstruction. However, the appropriate radiation dose level has not yet been established.We report the (DRL) for transnasal ileus tube placement in Japan. A longer procedure time and tube insertion length may be associated with DRL exceedance.

Occupational radiation exposure to the lens of the eyes and its protection during endoscopic retrograde cholangiopancreatography

This study aimed to examine occupational radiation exposure to the lens of the eyes during endoscopic retrograde cholangiopancreatography (ERCP). In this multicenter, prospective, observational cohort study, we collected data regarding occupational radiation exposure to the lens of the eyes during ERCP. We measured radiation exposure of patients and examined its correlation with occupational exposure. In dosimetrically-measured ERCPs (n = 631), the median air kerma at the patient entrance reference point, air kerma-area product, and fluoroscopy time were 49.6 mGy, 13.5 Gycm2, and 10.9 min, respectively. The median estimated annual radiation dose to the lens of the eyes was 3.7, 2.2, and 2.4 mSv for operators, assistants, and nurses, respectively. Glass badge over lead aprons and eye dosimeter results were similar in operators but differed in assistants and nurses. A strong correlation was shown between eye dosimeter measurements and patients' radiation exposure. The shielding rates of the lead glasses were 44.6%, 66.3%, and 51.7% for operators, assistants, and nurses, respectively. This study revealed the actual occupational exposure dose for the lens of the eyes during ERCP and the efficacy of lead glass. Values of radiation exposure to patients can help estimate exposure to the lens of the eyes of medical staff.

A follow-up questionnaire survey 2022 on radiation protection among 464 medical staff from 34 endoscopy-fluoroscopy departments in Japan

OBJECTIVES

We surveyed and reported low protective equipment usage and insufficient knowledge among endoscopy-fluoroscopy departments in Japan in 2020. Two years later, we conducted a follow-up survey of doctors, nurses, and technologists in Japan.

METHODS

We conducted a questionnaire survey on radiation protection from May to June 2022. The participants were medical staff, including doctors, nurses, and radiological and endoscopy technicians in endoscopy-fluoroscopy departments. The questionnaire included 17 multiple-choice questions divided into three parts: background, equipment, and knowledge.

RESULTS

We surveyed 464 subjects from 34 institutions. There were 267 doctors (58%), 153 nurses (33%), and 44 technologists (9%). The rate of wearing a lead apron was 98% in this study. The rates of wearing a thyroid collar, lead glasses, and radiation dosimeter were 27%, 35%, and 74%, respectively. The trend of the protective equipment rate was similar to that of our previous study; however, radiation dosimetry among doctors was still low at 58%. The percentage of subjects who knew the radiation exposure (REX) dose of each procedure was low at 18%. Seventy-six percent of the subjects attended lectures on radiation protection, and 73% knew about the three principles of radiation protection; however, the concept of diagnostic reference levels was not well known (18%). Approximately 60% of the subjects knew about the exposure dose increasing cancer mortality (63%) and the 5-year lens REX limit (56%).

CONCLUSIONS

There was some improvement in radiation protection equipment or education, but relatively little compared to the 2020 survey of endoscopy departments.

Radiation exposure during modern therapeutic endoscopic ultrasound procedures and standard alternatives

Background and study aims  Therapeutic EUS (t-EUS) is increasingly being adopted in clinical practice in tertiary referral centers; however, little is known about radiation exposure (RE) metrics and diagnostic reference limits for it. Methods  Kerma-area product (KAP [Gy·cm ² ]), Air Kerma and fluoroscopy time were retrospectively evaluated for all consecutive t-EUS procedures performed in San Raffaele Institute between 2019 and 2021. For EUS-guided choledochoduodenostomies (EUS-CDS) and gastroenterostomies (EUS-GE), an equal number of endoscopic retrograde cholangiopancreatographies (ERCPs) plus metal stenting and duodenal stents were included respectively for comparison. Results  Data from 141 t-EUS procedures were retrieved (49 % pancreatic cancer, 38 % peripancreatic fluid collections). EUS-CDS (N = 44) were mainly performed fluoroless, while ERCPs required a significantly higher RE (KAP = 25 [17-55], P < 0.0001). Fluid collection drainage (EUS-FCD) with lumen apposing metal stents (LAMS, N = 26) were performed fluoroless, while EUS-FCD with double-pigtail plastic stents (DPPS, N = 28) required higher RE (KAP = 23 [13-45]). EUS-guided gallbladder drainage (EUS-GBD, N = 6) required scarce RE (KAP = 9 [3-21]) for coaxial DPPS placement. EUS-GE (N = 27) required higher RE than duodenal stenting (KAP = 44 [28-88] versus 29 [19-46], P = 0.03). EUS-guided hepaticogastrostomies (EUS-HGS, N = 10) had the highest RE among t-EUS procedures (KAP = 81 [49-123]). Procedure complexity or intervening complications were evaluated and resulted in higher RE within each procedure. Conclusions  t-EUS procedures have different RE ( P  < 0.000001). EUS-CDS, EUS-GBD, and EUS-FCD with LAMS can be performed with no-to-mild radioscopy, unlike standard alternatives. However, radioscopy remains essential in case of technical difficulties or complications. EUS-GE and EUS-HGS involve a high RE. Endoscopists involved in t-EUS might experience RE higher than category standards, which indicates a need for increased awareness and personalized preventive measures.

Prediction model using clinical factors for radiation exposure during endoscopic retrograde cholangiopancreatography

BACKGROUND AND AIM

Endoscopic retrograde cholangiopancreatography (ERCP) requires radiation. This study aimed to assess the clinical factors influencing radiation exposure and devise a scoring model for predicting high-dose radiation exposure.

METHODS

Endoscopic retrograde cholangiopancreatography cases recorded between 2016 and 2019 in a single tertiary teaching hospital were retrospectively reviewed. A scoring model was created by bootstrap method in a derivation cohort (2016-2018) and was assessed in a validation cohort (2019).

RESULTS

Out of 4223 ERCPs, 2983 and 1240 cases were included in the derivation and validation cohorts, respectively. In the derivation cohort, 746 cases (top 25%) comprised the high-dose exposure group, and 2237 cases (bottom 75%) comprised the low-dose exposure group. Nine clinical parameters associated with high-dose exposure were male, pancreatic sphincterotomy, balloon dilatation, biliary or pancreatic drainage, procedures with contrast dye, endoscopist, in-hospital ERCP, and spot image. Stone removal was included by bootstrap analysis. As presented in a nomogram, the weight score of each variable was as follows: male, 1; pancreatic sphincterotomy, 3; balloon dilatation, 7; stone removal, 3; biliary or pancreatic drainage, 5; procedures with contrast dye, 1; endoscopist B, 4; endoscopist C, 5; in-hospital procedure, 3; and spot image, 3. A total score ≥ 15 suggested a high-dose radiation exposure. The sensitivity and specificity of the model for high-dose exposure were 0.562 and 0.813, respectively. In the validation cohort, the model showed reasonable predictability.

CONCLUSIONS

Various factors were associated with radiation exposure. The simple scoring system in this study could guide endoscopists in predicting the risk of high-dose radiation exposure.