Measures of patient radiation exposure during endoscopic retrograde cholangiography: Beyond fluoroscopy time

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.

Characterization of patient dose distributions and probabilistic risk analysis in cardiovascular catheterization laboratories

Purpose: Patient radiation doses in cardiovascular and interventional radiology are highly variable for similar procedures. This random nature may be better described by a distribution function, compared to a linear regression. This study develops a distribution function to characterize patient dose distributions and estimate probabilistic risk.Methods: Reference air kerma from 8647 patients over six years were retrospectively collected from an EP lab and two Cath labs. Data was first sorted into low dose (<100mGy) and high dose cases (>100mGy), and histograms of the data created. Dagum and Inverse gamma distributions were chosen to initially fit to both low and high dose cases. Fits between model and the data was optimized, and a linear regression analysis performed to obtain R squared values and standard errors for the correlation between model and data. Risk probabilities were estimated according to the modeled distribution function. BMI and time distributions were analyzed to understand their influence on the inverse gamma distribution error found in the data. 75th percentiles from both descriptive statistics and model were calculated.Results: The inverse gamma distribution can be used to characterize radiation dose distributions. Model predicted cases for radiation dose 3000mGy< x <5000mGy and >5000mGy are approximately 42 and 0 for 3651 cases for lab#1, and 14 and 1 for 3197 cases for lab#2, respectively, while the actual cases are 10 and 0, and 16 and 2. Descriptive and model statistics generated different 75th percentile levels for sorted data compared to unsorted data. Time has a greater influence on inverse gamma distribution function than BMI.Conclusion: This study creates a framework to understand the random error present in radiology practices that cause wide variations in patient radiation doses. It also provides an approach to evaluate different IR areas in terms of effectiveness of dose reduction measures.

Minimizing radiation exposure in endoscopic retrograde cholangiopancreatography: a review for medical personnel

Fluoroscopy is used frequently during endoscopic procedures, such as endoscopic retrograde cholangiopancreatography (ERCP). However, exposure to radiation is an important health concern, primarily because of the potential increase in the lifetime risk of malignancy. This consideration is important for patients and staff exposed to radiation during ERCP. Thus, an understanding of how radiation doses are measured during ERCP and the potential risks of this radiation is important. Additionally, staff must be educated about methods used to minimize the radiation dose, such as the use of different imaging techniques, the general principles of fluoroscopy, and advances in hardware and software. The use of personal protective equipment is also essential to minimize occupational exposure. However, no comprehensive ERCP guideline on the use of X-ray systems in clinical settings or on radiation protection for operators has been established. This review focuses on the properties of fluoroscopy systems and methods of radiation protection for physicians and assistants participating in ERCP.

[A Simple Measurement Method for Verifying the Accuracy of the Displayed Dose on an Over-couch-type X-ray Fluoroscopic System]

The purpose of this study was to establish a simple measurement method to verify the accuracy of incident air kerma (K_{a, r}) and air kerma area product (P_KA) displayed on an over-couch-type X-ray fluoroscopy system. A dosimeter was located at the patient entrance reference point, and the irradiation field size was set to 10×10 cm. A lead plate was placed on the couchtop to protect the image receptor, and the duration of fluoroscopy was set to 1 min. The K_{a, r} was measured with the proposed method and the Japanese Industrial Standards (JIS) method on three X-ray fluoroscopy units of different manufactures. The effect of backscattered X-rays from the lead plate was calculated using Monte Carlo methods. The errors of the displayed K_{a, r} and P_KA to the measured K_{a, r} and P_KA with our proposed method were calculated. There was no significant difference in the measured K_{a, r} between the proposed method and the JIS method in all units. The effect of backscattered X-ray was ≤0.5%. The errors of displayed K_{a, r} and P_KA to those measured were in the range of 3.4 to 15.7% and -4.1 to 20.3%, respectively, which met the tolerance for accuracy of ±35% in accordance with the JIS method. We found that our proposed method was simple and that the accuracy of measured values was comparable to that of the JIS method.

Reduced Fluoroscopy Time With Physician-Controlled Fluoroscopy During Endoscopic Retrograde Cholangiopancreatography: A Community Hospital Experience

Background and objective

Fluoroscopy during endoscopic retrograde cholangiopancreatography (ERCP) is associated with radiation exposure and related health risks. Either the physician or the radiology technologist can activate fluoroscopy during ERCP. The aim of this study was to determine if physician-controlled fluoroscopy is associated with decreased fluoroscopy time, which may correspond to less radiation exposure to patients and staff. 

Methods

We conducted a single-center, retrospective study; data were collected on ERCP performed using physician-controlled and technologist-controlled fluoroscopy. Fluoroscopy time, procedure complexity level, and Stanford Fluoroscopy Score were compared between the two groups.

Results

The median fluoroscopy time significantly differed between the two groups with 108 seconds for physician-controlled and 146 seconds for technologist-controlled procedures (p=0.004). The ratio of median fluoroscopy time to procedure complexity level was significantly lower in the physician-controlled group at 73.0 seconds compared to 97.0 seconds in the technologist-controlled group (p=0.002). The ratio of median fluoroscopy time to Stanford Fluoroscopy Score was 25.5 seconds in the physician-controlled group compared to 39.3 seconds in the technologist-controlled group, which was also statistically significant (p<0.001). A subgroup analysis of physicians with advanced training in ERCP also showed a significantly reduced median fluoroscopy time to Stanford Fluoroscopy Complexity Score ratio: 25.5 seconds for physician-controlled versus 35.0 seconds for technologist-controlled (p=0.001).

Conclusion

The ERCP technique with physician-controlled fluoroscopy may be associated with shorter fluoroscopy time. This may correspond to decreased radiation exposure to patients compared to radiology technologist-controlled fluoroscopy. Further investigations with larger, prospective studies are warranted.

Assessment of radiation doses received by patients during endoscopic retrograde cholangiopancreatography according to disease location

OBJECTIVE

patients are exposed to ionizing radiation during endoscopic retrograde cholangiopancreatography (ERCP). Radiation dose depends on multiple factors. The goal of this study was to assess fluoroscopy time (FT), radiation doses and effective dose (ED) during ERCP according to the condition being treated.

MATERIALS AND METHODS

a descriptive study was performed of 369 consecutive ERCPs from January 2017 to June 2019. Patient demographic and procedure data were collected. FT, cumulative dose area product (DAP), fluoroscopy DAP, DA fluoroscopy, air kerma, and number of radiographs were assessed. ED was estimated using specific conversion factors.

RESULTS

the mean age was 73.34 years and 193 subjects were male. Mean FT was 4.56 ± 0.17 min, cumulative DAP was 2,056.73 ± 188.83 cGycm2, fluoroscopy DAP was 1,722.90 ± 82.26 cGycm2 and air kerma was 85.84 ± 4.93 mGy. The number of radiographs was 2.10 ± 0.07 and the mean ED was 5.34 ± 0.49 mSv. FT was significantly longer for choledocholithiasis (CL), proximal malignant biliary stricture (PMBS) and distal malignant biliary stricture (DMBS) versus others (OT). Cumulative DAP was higher for PMBS (p < 0.002). FT, cumulative DAP, fluoroscopy DAP and air kerma values were significantly higher for complicated CL as compared to simple CL. ED was higher for CL, DMBS and PMBS, but only significantly (p < 0.002) for PMBS.

CONCLUSIONS

FT for ERCP is variable and increases with exploration difficulty. Thus, it is longer in the case of PMBS, as well as with the amount of radiation received by the patients and ED.

Usefulness of an additional lead shielding device in reducing occupational radiation exposure during interventional endoscopic procedures: An observational study

Adoption of interventional endoscopic procedures is increasing with increasing prevalence of diseases. However, medical radiation exposure is concerning; therefore, radiation protection for medical staff is important. However, there is limited information on the usefulness of an additional lead shielding device during interventional endoscopic procedures. Therefore, we aimed to determine whether an additional lead shielding device protects medical staff from radiation.An X-ray unit (CUREVISTA; Hitachi Medical Systems, Tokyo, Japan) with an over-couch X-ray system was used. Fluoroscopy-associated scattered radiation was measured using a water phantom placed at the locations of the endoscopist, assistant, nurse, and clinical engineer. For each location, measurements were performed at the gonad and thyroid gland/eye levels. Comparisons were performed between with and without the additional lead shielding device and with and without a gap in the shielding device. Additionally, a clinical study was performed with 27 endoscopic retrograde cholangiopancreatography procedures.The scattered radiation dose was lower with than without additional lead shielding at all medical staff locations and decreased by 84.7%, 82.8%, 78.2%, and 83.7%, respectively, at the gonad level and by 89.2%, 86.4%, 91.2%, and 87.0%, respectively, at the thyroid gland/eye level. Additionally, the scattered radiation dose was lower without than with a gap in the shielding device at all locations.An additional lead shielding device could protect medical staff from radiation during interventional endoscopic procedures. However, gaps in protective equipment reduce effectiveness and should be eliminated.

Radiation exposure during endoscopic retrograde cholangiopancreatography according to clinical determinants

This study aimed to analyze the dose of radiation to which the physician is exposed during endoscopic retrograde cholangiopancreatography (ERCP) and to identify predictive factors of radiation exposure during the procedure. Furthermore, we evaluated the patient characteristics and procedural factors associated with prolonged fluoroscopy time (FT).A cross-sectional retrospective analysis of 780 ERCPs performed at a tertiary academic hospital over a 2-year period was conducted. The primary outcome was radiation exposure during ERCP as determined by FT; additionally, the association between variables and radiation exposure was determined. Moreover, we evaluated their correlations with age, sex, body mass index (BMI), diagnosis, duration of procedure, procedure name, and procedure complexity.According to the analysis of the 780 ERCPs performed in 2 years, the mean FT was 5.07 minutes (95% confidence interval [CI], 4.87-5.26). The mean radiation durations were as follows: cholelithiasis, 5.76 minutes (95% CI, 4.75-6.80); malignant biliary obstruction, 6.13 minutes (95% CI, 5.91-6.35); pancreatic disease, 5.28 minutes (95% CI, 4.45-6.28); and benign biliary stricture, 5.32 minutes (95% CI, 5.02-5.94). Significant differences affecting fluoroscopy duration between the 2 endoscopists were not observed in the present study. Multivariate analysis revealed that prolonged fluoroscopy duration was related to specific characteristics, including higher BMI (BMI >27.5 kg/m) (+4.1 minutes; 95% CI, 2.56-5.63), mechanical lithotripsy (+4.85 minutes; 95% CI, 0.45-9.25), needle-knife use (+4.5 minutes; 95% CI, 2.15-6.86), and malignant biliary obstruction (+2.34 minutes; 95% CI, 0.15-4.53).ERCPs are associated with significantly higher radiation exposure of patients on the specific procedure. Endoscopists should be aware of the determining factors, including patients with obesity, who underwent mechanical lithotripsy, who had malignant biliary obstruction, and who underwent a procedure using a needle knife, that affect FT during ERCP.

Ocular radiation exposure during endoscopic retrograde cholangiopancreatography: a meta-analysis of studies

BACKGROUND

The increasing complexity involved in procedures requiring fluoroscopy such as endoscopic retrograde cholangiopancreatography (ERCP) results in heightened screening times with attendant radiation exposure during these procedures. There is increasing awareness of tissue-reactions to the lens of the eye due to radiation exposure, with evidence suggesting that threshold doses may be lower than previously considered.

MATERIALS AND METHODS

A literature search was performed to identify studies involving ERCP in which radiation exposure was reported. Demographic data and data on fluoroscopy time and ocular exposure were extracted. Fixed and random-effects meta-analyses were conducted.

RESULTS

Twenty-six studies (8016 procedures) were identified, of which 10 studies (818 procedures) contained data on ocular exposure. The mean screening time per procedure was 3.9 min with a mean of three images captured per procedure. On fixed effects meta-analysis, the point estimate for the effective ocular exposure dose per procedure was 0.018 (95% confidence interval: 0.017-0.019) mSv. On random-effects meta-analysis, the effective ocular exposure dose was 0.139 (0.118-0.160) mSv (Q=2590.78, I=99.5, P<0.001). On comparing these point estimates to the ocular dose limit of 20 mSv/year, 1111 ERCPs (using fixed effects data) and 144 ERCPs (using random-effects data), with a mean of 627 ERCPs/individual/year, could deliver an ocular radiation dose equivalent to this dose limit.

CONCLUSION

Ocular radiation exposures in high-volume ERCP operators (>200 procedures/year) and operators performing complex ERCPs involving prolonged fluoroscopy, need to exercise caution in relation to ocular exposure. Shielding using lead-lined glasses may be reasonable in this group.

Radiation exposure during image-guided endoscopic procedures: The next quality indicator for endoscopic retrograde cholangiopancreatography

Endoscopic retrograde cholangiopancreatography (ERCP) is one of the most frequently used image-guided procedures in gastrointestinal endoscopy. Post-ERCP pancreatitis is an important concern, and prophylaxis, cannulation and other related technical procedures have been well documented by endoscopists. In addition, medical radiation exposure is of great concern in the general population because of its rapidly increasing frequency and its potential carcinogenic effects. International organizations and radiological societies have established diagnostic reference levels, which guide proper radiation use and serve as global standards for all procedures that use ionizing radiation. However, data on gastrointestinal fluoroscopic procedures are still lacking because the demand for these procedures has recently increased. In this review, we present the current status of quality indicators for ERCP and the methods for measuring radiation exposure in the clinical setting as the next quality indicator for ERCP. To reduce radiation exposure, knowledge of its adverse effects and the procedures for proper measurement and protection are essential. Additionally, further studies on the factors that affect radiation exposure, exposure management and diagnostic reference levels are necessary. Then, we can discuss how to manage medical radiation use in these complex fluoroscopic procedures. This knowledge will help us to protect not only patients but also endoscopists and medical staff in the fluoroscopy unit.

Quality indicators for endoscopic retrograde cholangiopancreatography. The procedure of endoscopic retrograde cholangiopancreatography

The goal of the project encompassing the present paper is to propose useful quality procedures and indicators in order to improve quality in digestive endoscopy units. In this third part outcome procedures and indicators are suggested for endoscopic retrograde cholangiopancreatography (ERCP). First, a diagram of pre- and post-ERCP steps was developed. A group of experts in healthcare quality and/or endoscopy, under the shelter of the Spanish Society of Digestive Diseases (Sociedad Española de Patología Digestiva - SEPD), carried out a qualitative review of the literature regarding quality indicators for ERCP. Then, a paired analysis was used for the selection of identified references. A total of six specific indicators, apart from the common indicators already described, were identified, all of them process indicators (two pre-procedure and four post-procedure). Evidence quality was analyzed for each indicator using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) classification.

The difference in ocular lens equivalent dose to ERCP personnel between prone and left lateral decubitus positions: a prospective randomized study

BACKGROUND AND STUDY AIMS

 Endoscopic retrograde cholangiopancreatography (ERCP) is commonly performed in a prone or left lateral decubitus (LLD) position. The ocular lens equivalent doses between the two positions may be different because in the LLD position the tube voltage will automatically increase to maintain the image quality, and the increased distance between the image intensifier and the X-ray tube may result in more scattered radiation. We aimed to compare the ocular lens equivalent doses of ERCP personnel between the two different positions.

PATIENTS AND METHODS

 Fifty-five patients with ERCP indications were randomized to either prone or LLD positions. One patient in an LLD position was excluded due to technical reasons. Indications for ERCP, patients' vertical thicknesses, fluoroscopy parameters, patients' skin dose rates, and the ocular-lens equivalent doses of ERCP personnel were compared.

RESULTS

 Baseline characteristics were no different except for vertical thickness, which was significantly higher in the LLD group. The ocular lens equivalent doses (prone vs. LLD) of the primary endoscopist (19.2 vs. 30.7 µSv, P  = 0.035), and the nurse anesthetist (17.3 vs. 42.2 µSv, P  = 0.002) were significantly lower in the prone group than in the LLD group. The calculated annual number of procedures not to exceed the exposure allowance in prone and LLD positions were 1,042 and 651 procedures for the primary endoscopist and 1,157 and 473 procedures for the nurse anesthetist, respectively.

CONCLUSIONS

 Ocular-radiation exposure to ERCP personnel was one-third lower in the prone than in LLD position. Therefore, more annual ERCPs could be performed by the personnel.

Occupation-associated health hazards for the gastroenterologist/endoscopist

Advances in the field of endoscopy have allowed gastroenterologists to obtain detailed imaging of anatomical structures and to treat gastrointestinal diseases with endoscopic therapies. However, these technological developments have exposed endoscopists and staff to hazards such as musculoskeletal injuries, exposure to infectious agents, and ionizing radiation. We aimed to review the occupational hazards for the gastroenterologist and endoscopist. Using PubMed, Medline, Medscape, and Google Scholar, we identified peer-reviewed articles with the keywords “occupational hazards,” “health hazards,” “occupational health hazards,” “endoscopy,” “gastroenterologist,” “infectious agents,” “musculoskeletal injuries,” and “radiation.” Strategies for reducing exposure to infectious agents, radiation, and the risk of musculoskeletal injuries related to gastroenterology include compliance with established standard measures, the use of thyroid shields and radioprotective eyewear, and ergonomic practices. We conclude that educating endoscopic personnel and trainees in these practices, in addition to further research in these areas, will likely lead to the development of more efficient and user-friendly workspaces that are safer for patients and personnel.

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.

Effectiveness of additional lead shielding to protect staff from scattering radiation during endoscopic retrograde cholangiopancreatography procedures

Endoscopic retrograde cholangiopancreatography (ERCP) is often complex and involves long fluoroscopic times, with significant radiation exposure to medical staff. We investigated protective effects of an additional attached lead shielding device. The lead shielding device covered with the X-ray tube table (0.125 mm lead equivalent) during ERCP procedures. Fluoroscopy scatter radiation, with or without the lead shielding device, was measured using an acrylic phantom and a radiation survey meter. Measurements (25 points) were made at 50 cm intervals, at both 90 and 150 cm above the floor. We created radiation maps, with and without the additional lead shielding device. Moreover, we monitored annual staff exposure to radiation, before and after inclusion of the shielding device. Without additional shielding, exposure doses at the physician's position, 90 and 150 cm above the floor, were 1940 and 4040 (μSv/h) respectively. In contrast, with the shielding device, corresponding exposures were 270 and 450 (μSv/h) at 90 and 150 cm, respectively. Scattered radiation was decreased by 86.1% at 90 cm or 88.9% at 150 cm. However, with additional lead shielding in the middle, rather than hung over the operating table, scattered radiation was decreased by only ~10%. The staff's annual dose equivalents (DEs) were 12.2-29.8 mSv/year without and 3.8-8.4 mSv/year with lead shielding. With lead shielding, dose equivalent values for the staff were decreased by 41.0-76.5%. Thus, with additional lead shielding, properly used, scattered radiation would be decreased by ~90%, thus decreasing exposure doses to medical staff during ERCPs.

Effectiveness and safety of endoscopic sphincterotomy and papillary balloon dilatation in treatment of extrahepatic bile duct stones

AIM: To compare the effectiveness and safety of endoscopic sphincterotomy (EST) and papillary balloon dilatation (EPBD) in the treatment of extrahepatic bile duct stones.

METHODS: Two hundred and seventeen patients with extrahepatic bile duct stones treated by EST or EPBD were included in this study, and the therapeutic effect, X-ray exposure time and complications were compared and analyzed.

RESULTS: The complete clearance rate of stones did not differ between the EST group and EPBD group (93.8% vs 94.3%, P > 0.05), and the X-ray exposure time was significantly shorter in the EPBD group than in the EST group (P < 0.05). There was no significant difference in the incidence rate of complications between the two groups (P > 0.05), but the incidence rate of post-endoscopic pancreatitis was significantly higher in the EPBD group than in the EST group (12.5% vs 4.7%, P < 0.05). All 17 cases of post-endoscopic pancreatitis were mild. The hemorrhage rate was significantly higher in the EST group than in the EPBD group (11.6% vs 3.4%, P < 0.05); all the 18 cases of hemorrhage were controllable. The rate of recurrent bile duct stones with acute cholangitis of severe type (ACST) was significantly higher in the EST group than in the EPBD group (44.1% vs 18.2%, P < 0.05).

CONCLUSION: Both EST and EPBD are mature and safe methods to treat extrahepatic bile duct stones, but EPBD can better protect the function of Oddi sphincter and reduce the incidence of long-term complications.