Radiation Doses to Operators in Hepatobiliary Interventional Procedures

Radiation dose during transarterial chemoembolization and associated factors

PURPOSE

To provide detailed reports on radiation doses during transarterial chemoembolization (TACE) in the cone-beam computed tomography (CBCT) era and to identify the associated factors.

METHODS

This retrospective study included 385 consecutive patients who underwent initial conventional TACE for hepatocellular carcinoma (HCC) between January 2016 and December 2017. In most cases, CBCT was performed at the common hepatic artery or celiac axis to confirm the location of the tumor and the three-dimensional hepatic artery anatomy. Superselective TACE was performed for all technically feasible cases. Information on total dose area product (DAP), total cumulative air kerma (CAK), fluoroscopy time, and DAP and CAK of each digital subtraction angiography (DSA) and CBCT scan was recorded. Multiple linear regression analysis was performed to identify the factors associated with increased DAP during TACE.

RESULTS

The mean values of total DAP and CAK were 165.2 ± 81.2 (Gy·cm²) and 837.1 ± 571.0 (mGy), respectively. The mean fluoroscopy time was 19.1 ± 10.3 min. The mean DAP caused by fluoroscopy, DSA, and CBCT was 51.8 ± 43.9, 28.0 ± 24.1, and 83.9 ± 42.1 Gy·cm², respectively. Male sex, a high body mass index, largest tumor size > 3 cm, presence of aberrant right and left hepatic arteries, and superselective TACE were identified as independent predictors of increased total DAP during TACE.

CONCLUSION

We were able to provide detailed reports on radiation doses during TACE and associated factors.

3D Printed Percutaneous Transhepatic Cholangiography and Drainage (PTCD) Simulator for Interventional Radiology

PURPOSE

Learning how to perform percutaneous transhepatic bile duct drainage (PTCD) is challenging for interventional radiology (IR) trainees. Therefore, simulators are crucial for IR training and are being increasingly demanded in the evolving healthcare environment of value-based care. To facilitate interventional training, we tried to evaluate our newly developed liver phantom for further use in IR training.

METHODS

We developed a liver phantom with a flexible hollow biliary tree, hydrogel-based liver parenchyma, plastic ribs, and silicone skin. The phantom was evaluated by 20 radiology residents from two hospitals. After an introduction, all participants tried to obtain biliary access by fluoroscopic guidance within 25 min. Puncture time, fluoroscopy time, and kerma area product were measured. After 7 days, the participants repeated the procedure on an altered and more difficult model. Additionally, a survey was handed out to every participant (20 residents, 5 experts, and 5 IR fellows) to evaluate the phantom in terms of accuracy and haptic feedback, as well as general questions regarding simulation.

RESULTS

The residents performed significantly faster and were more self-confident on Day 7 than on Day 1, significantly decreasing puncture time, fluoroscopy time, and kerma area product (p ≤ 0.0001). The participants were very satisfied with their simulation experience and would trust themselves more in real-life scenarios.

CONCLUSION

We were able to develop a phantom with high anatomical accuracy for fluoroscopy and ultrasound-guided interventions. The phantom successfully helped residents learn and improve their PTCD performance.

LOCAL DIAGNOSTIC REFERENCE LEVELS FOR PEDIATRIC RETROGRADE WEDGE PORTOGRAPHY INTERVENTIONAL PROCEDURES USING A DOSE MONITORING SOFTWARE AT A TRANSPLANTATION INSTITUTE

The aim of this work was to establish local diagnostic reference levels (DRLs) for retrograde wedge portography (RWP) performed on pediatric patients assessing the usefulness of radiation dose monitoring software in the establishing process. Between September 2016 and April 2020, 66 consecutive RWP were performed at a transplantation institute and were included in our study. Patients were divided in three groups according to age: n = 25 infants, n = 20 middle childhood and n = 21 early adolescence. The third quartile of both Air Kerma at the reference point (Ka,r) and air kerma-area product (PKA) were evaluated to establish local DRLs (lDRLs). In addition, to control high Ka,r levels during procedures, the software notified to operators if Ka,r exceeded the dose 'alert' threshold set at 2 Gy. lDRLs were established for all three groups using PKA and Ka,r: infant group: 5.6 Gy.cm 2 and 0.034 Gy; middle childhood: 6.4 Gy.cm2 and 0.018 Gy and early adolescence: 12.8 Gy.cm2 and 0.059 Gy. The dose threshold 'alert' was never encountered (alert quota: 0%). The dose monitoring system supports the feasibility of accurate and easier lDRLs' establishment.

Occupational dose and associated factors during transarterial chemoembolization of hepatocellular carcinoma using real-time dosimetry: A simple way to reduce radiation exposure

Transarterial chemoembolization is the standard treatment option for intermediate-stage hepatocellular carcinoma (HCC). However, during the interventional procedure, occupational radiation protection is compromised. The use of real-time radiation dosimetry could provide instantaneous radiation doses. This study aimed to evaluate the occupational dose of the medical staff using a real-time radiation dosimeter during transarterial chemoembolization (TACE) for HCC, and to investigate factors affecting the radiation exposure dose.This retrospective observational study included 70 patients (mean age: 66 years; age range: 38-88 years; male: female = 59: 11) who underwent TACE using real-time radiation dosimetry systems between August 2018 and February 2019. Radiation exposure doses of operators, assistants, and technicians were evaluated. Patients' clinical, imaging, and procedural information was analyzed.The mean dose-area product (DAP) and fluoroscopy time during TACE were 66.72 ± 55.14 Gycm2 and 12.03 ± 5.95 minutes, respectively. The mean radiation exposure doses were 24.8 ± 19.5, 2.0 ± 2.2, and 1.65 ± 2.0 μSv for operators, assistants, and technicians, respectively. The radiation exposure of the operators was significantly higher than that of the assistants or technicians (P < .001). The perpendicular position of the adjustable upper-body lead protector (AULP) on the table was one factor reducing in the radiation exposure of the assistants (P < .001) and technicians (P = .040). The DAP was a risk factor for the radiation exposure of the operators (P = .003) and technicians (P < .001).Occupational doses during TACE are affected by DAP and AULP positioning. Placing the AULP in the perpendicular position during fluoroscopy could be a simple and effective way to reduce the radiation exposure of the staff. As the occupational dose influencing factors vary by region or institution, further study is needed.

Local dose reference levels during transarterial chemoembolization procedure

The aim of this study was to develop local diagnostic reference levels (LDRL) during Transarterial chemoembolization (TACE). This cross-sectional study reports radiation dose indicators of 108 patients in a Mexican hospital, obtained over a period of 35 months. Kerma-area product (P_KA), air-kerma at the reference point (K_{a, r}), and descriptive statistical analysis were examined according to sociodemographic characteristics of the sample patients. The LDRL obtained were then compared to a similar international framework. The present study contributes to the establishment of a TACE LDRL and identifies significant correlations among radiology factors and dosimetric quantities obtained.

A critical appraisal of the quality of guidelines for radiation protection in interventional radiology using the AGREE II tool: A EuroAIM initiative

PURPOSE

To systematically review and assess the methodological quality of guidelines for radiation protection in interventional radiology.

MATERIALS AND METHODS

On April 15^th, 2021, a systematic search for guidelines on radiation protection in interventional radiology was performed using MEDLINE, EMBASE, National Guideline Clearinghouse, and National Institute for Health and Clinical Excellence databases. Among retrieved guidelines, we then excluded those not primarily focused on radiation protection or on interventional radiology. Authors' professional role and year of publication were recorded for each included guideline. Guideline quality evaluation was performed independently by three authors using the six-domain tool "AGREE II", with an overall guideline quality score divided into three classes: low (<60%), acceptable (60-80%), and good quality (>80%).

RESULTS

Our literature search identified 106 citations: after applying exclusion criteria, 11 guidelines published between 2009 and 2018 were included, most of their authors being interventional radiologists (168/224, 75%). Overall quality of included guidelines was acceptable (median 72%, interquartile range 64-83%), with only one guideline (9%) with overall low quality and four guidelines (36%) with overall good quality. Among AGREE II domains, "Scope and Purpose", "Clarity of Presentations", and "Editorial Independence" had the best results (87%, 76%, and 75% respectively), while "Applicability", "Rigor of Development", and "Stakeholder Involvement" the worst (46%, 49%, and 52% respectively).

CONCLUSION

Considering all guidelines, the overall methodological quality was acceptable with one third of them reaching the highest score class. The "Applicability" domain had the lowest median score, highlighting a practical implementation gap to be addressed by future guidelines.

Percutaneous transhepatic biliary puncture simulator: a cord network prototype

Background

The aim of this study was to present a percutaneous transhepatic biliary puncture simulator that can be used without radiation exposure and that reflects the conventional anatomy of the biliary ducts and its vicinity structures.

Methods

An anatomically based model of the biliary tree was developed using a cord network fixed to a wooden frame. The skin, ribs, intercostal muscles, and right lower lobe pleura were simulated using foam sponge, plastic tubes, a polystyrene foam panel, and an air pad, respectively. For the puncture, we used a 20-G Chiba needle and a wire with distal double arches; these were used to troll a cord, simulating the successful puncture of a bile duct. A camera was also placed above the model to allow the trainees to train eye-hand coordination while viewing the image on a monitor in real time. The simulator was tested with 60 radiology residents to evaluate the confidence and skills transferability of the training model.

Results

After receiving an introduction of the system and 5 min of training under tutor surveillance, all participants were able to troll a cord of the biliary simulator by themselves in less than 4 min. Only one participant punctured the simulated pleura. The participants’ evaluations showed positive results, with increased user confidence and skills transferability after the training session.

Conclusions

This proposed simulator can be an effective tool to improve a trainee’s confidence and competence while achieving procedural and non-procedural interventional radiology skills related to the liver.

Trial registration

Retrospectively registered

FLUOROSCOPY-GUIDED BILIARY PROCEDURES IN A PREGNANT, LIVER TRANSPLANT PATIENT: FETUS RADIATION PROTECTION

We report three cases of clinically necessary, fluoroscopy-guided, percutaneous biliary procedures performed safely in a pregnant, liver transplant recipient using three different angiography suites. The uterine cumulative equivalent dose was 0.25 mSv, a value obtained by adding the doses of the three procedures described above, and which is relatively low when compared with the naturally occurring background radiation exposure for a 9-month pregnancy (~0.5-1 mSv). Our experience shows that staff knowledge, awareness and liaison promote the application of all dose reduction strategies possible while still achieving the clinical aim despite using different angiographic equipment.

OCCUPATIONAL RADIATION DOSE PERFORMING HEPATOBILIARY MINIMALLY INVASIVE PROCEDURES IN CHILDREN WEIGHING LESS THAN 20 kg

Our objective is to retrospectively evaluate the effective dose (E) of operators performing pediatric Hepatobiliary Minimally Invasive Procedures (HMIP). Between October 2015 and December 2017, 58 consecutive HMIP were performed on 26 children weighing less than 20 kg (mean 12.3 kg, median 13 kg, range 2.4-20 kg). About 31 vascular procedures (n = 9 hepatic venograms with/without stenting; n = 9 retrograde wedge portography; n = 8 transhepatic portography with angioplasty and/or stenting and n = 5 hepatic arteriography/embolization) and 27 non-vascular procedures (n = 6 percutaneous transhepatic biliary drainage (PTBD); n = 3 bilioplasty; n = 15 biliary catheter change and n = 3 cholangiogram) were performed. Electronic personal dosimeters were used to measure radiation doses to the interventional radiologist, radiographer and anesthesia nurse. The results shows the highest mean effective dose: interventional radiologist's in PTBD (1.18 μSv); radiographer's in hepatic veins phlebography with/without stenting (0.25 μSv) and nurse's in hepatic arteriography/embolization (0.26 μSv). Operators' E can vary depending on the complexity of procedure performed and the position of the operators within the angiosuite.

Protective Efficacy of Different Ocular Radiation Protection Devices: A Phantom Study

PURPOSE

The aim of this study was to investigate the efficacy of different designs and types of ocular radiation protection devices depending on simulated varied body heights in a phantom-simulated thoracic intervention.

MATERIALS AND METHODS

A clinical angiography system with a standardized fluoroscopy protocol with an anthropomorphic chest phantom as a scattering object and optically stimulated luminescence dosimeters for measuring radiation dose were used. The dosimeters were placed at the position of eyes of an anthropomorphic head phantom simulating the examiner. The head phantom was placed on a height-adjustable stand simulating the height of the examiner from 160 to 200 cm with 10 cm increments. The dose values were then measured with no radiation protection, a weightless-like radiation protection garment, radiation protection glasses and visors.

RESULTS

The average dose reduction using radiation protection devices varied between 57.7 and 83.4% (p < 0.05) in comparison with no radiation protection. Some radiation protection glasses and visors showed a significant dose reduction for the eye lenses when the height of the examiner increased. The right eye was partially less protected, especially if the distances between the simulated examiner's head and the scatter object were small.

CONCLUSION

All the investigated protection devices showed a significant reduction in radiation exposure to the simulated examiner. For some devices, the radiation dose increased with decreasing distance to the scattering object, especially for the right eye lens.

Endoscopist's occupational dose evaluation related to correct wearing of dosimeter during X-ray-guided procedures

Background Since endoscopists performing procedures in the endoscopy suite can change their position by turning their back, side or front toward the X-ray source, this study aimed to establish whether dosimeter position affects the correct evaluation of an endoscopist’s personal radiation exposure during X-ray-guided procedures.

Materials and methods Between January and February 2018, two dosimeters specularly placed outside the lead apron (anterior one on the chest and posterior one on the back) measured endoscopists’ personal dose equivalent (Hp) during 62 X-ray-guided procedures on adult and pediatric patients. Procedures were divided into three groups considering the position taken by the endoscopist with respect to the radiation source. For each group, the difference between mean Hp from the anterior and posterior dosimeters was calculated.

Results A statistically significant difference in mean Hp was recorded for the endoscopists’ frontal and back positions (P = 0.014, and P < 0.00001, respectively). No significant difference was found in mean Hp for the side position (P = 0.489).

Conclusions The position of personal dosimeters affects the correct evaluation of endoscopists’ radiation exposure during X-ray-guided procedures when frontal and back positions were recorded. To correctly evaluate radiation doses, the whole-body dosimeter should be worn according to the position of the endoscopist with respect to the radiation source; otherwise, it results in an incorrect personal dose evaluation, which may lead to substantial underestimation of staff exposure.

Transhepatic forceps biopsy combined with biliary drainage in obstructive jaundice: safety and accuracy

PURPOSE

This study was conducted in order to investigate the safety and accuracy of percutaneous transluminal forceps biopsy (PTFB) during percutaneous biliary drainage (PTBD) in patients with a suspicion of malignant biliary stricture.

MATERIAL AND METHODS

Fifty consecutive patients with obstructive jaundice underwent PTFB during PTBD. Biopsy specimens were obtained using 5.2-F flexible biopsy forceps and these specimens were independently analysed by two pathologists. Consensus was obtained in case of discrepancy. Biopsy was considered as a true positive when tumour cells were retrieved. In the absence of tumour cells, comparison with available surgical findings and/or endoscopic ultrasound fine-needle aspiration (EUS-FNA) and/or percutaneous liver biopsy and/or imaging or clinical follow-up was made to distinguish true and false negatives. Specificity, sensitivity, positive predictive value, negative predictive value and accuracy were calculated. Influence of tumour location and pre-operative imaging findings was evaluated. Adverse events were reported.

RESULTS

Biliary drainage and tissue sampling were achieved in 100% of patients. Sensitivity and specificity were 70 and 100%, respectively, while overall accuracy was 72%. After excluding the first 25 patients, accuracy and sensitivity for tissue sampling reached 80 and 78%, respectively. Sensitivity was better (87%) if stenosis was located at the upper part of the biliary tree, compared to the lower part (55%). In case of cholangiocarcinoma or intraductal invasion suspected on imaging, biopsy was contributive in 84 and 81% of patients, respectively. Four complications occurred consisting of one bile leak, two haemobilia and one pneumoperitoneum.

CONCLUSION

PTFB combined with PTBD is a safe and effective technique for both histopathological diagnosis and biliary decompression of biliary strictures.

KEY POINTS

Implications for patient care: • Percutaneous transbiliary forceps biopsy is technically feasible (100% of tissue sampling in our study) and is a safe technique. • Radiological management combining PTFB plus PTBD may allow diagnosis and treatment of the biliary stricture at the same time. • Sensitivity and accuracy for PTFB reached 78 and 80%, respectively, with a 100% specificity.