RPS 1409a - Interventional practice, dose management and education

RPS 1409a-K
Keynote lecture
RPS 1409a-1
Cost awareness of interventional radiology devices among radiology trainees
Purpose: Numerous disposable devices are consumed daily in interventional radiology (IR) suites globally. Trainees receive no formal training or assessment on the cost and identification of these devices. Educating specialists on disiposable devices has shown to reduce costs in other disciplines. This study aims to assess radiology trainees? ability to identify and estimate the costs of common disposable interventional radiological devices and identify deficiencies in postgraduate radiology teaching in terms of healthcare economics.
Methods: The postgraduate radiology training body of a European country was consulted to obtain numbers of all current radiology trainees. Trainees were invited to partake in a questionnaire via email. An anonymous online survey consisting of 26 multiple-choice questions (MCQs) was administered. Respondents were asked to provide their year of training and subspecialty of interest. Respondents were asked to identify 13 devices, using in vivo and ex vivo images. The devices were a PICC line, Angioseal closure device, tunnelled dialysis catheter, Port-A-Cath, pigtail drainage catheter, guidewire, biopsy needle, micropuncture kit, angioplasty balloon, IVC filter, covered metal vascular stent, gastrostomy tube, and an EVAR graft. They were asked to estimate the cost of each device. Trainees were deemed correct if they responded within 25% of true cost.
Results: The questionnaire was delivered to 82 radiology trainees; the response rate was 60% (49/82). No trainee accurately estimated the cost for all 13 devices assessed. The cost of devices was underestimated by trainees 48.9% of the time and overestimated 32.3% of the time.
Conclusion: Radiology trainees are deficient in cost awareness of a number of common IR devices used. A health economics module in postgraduate radiology training may improve the efficiency of healthcare expenditure within radiology departments.
Limitations: n/a
Ethics: n/a
Funding: No funding was received for this work.
RPS 1409a-2
A pilot study to compare the perception of image quality using smart glasses and a conventional monitor
Purpose: Due to the hands-free nature of smart glasses, they have the potential to be useful in interventional environments where sterility has to be ensured and where the clinician has both hands occupied with surgical tasks. A visual grading analysis (VGA) study was performed to compare the perceived image quality of fluoroscopy images using smart glasses and a conventional monitor.
Methods: 10 observers (3rd-year student radiographers) evaluated 4 anonymised fluoroscopic images for 4 criteria (representation of soft tissue structures, bone, contrast filled structures, and clear definition of a guidewire). Each criterion was rated on a scale of 1-5, with a higher number representing a more positive response.
The evaluation was completed with a pair of prototype Epson BT-35E smart glasses (Epson, Japan) in a controlled environment (dimmed ambient lighting with no adjustments made to the brightness, contrast, or magnification settings). The same images were also displayed on an Iiyama ProLite B2206WS monitor (Iiyama, Japan) within the same controlled environment. The area under the visual grading characteristic (AUCVGC) was used as the figure of merit (FOM). The image evaluation would be considered statistically different if the 95% confidence interval (CI) of the AUCVGC did not include 0.5.
Results: The AUCVGC and 95% CI was 0.519 (0.425, 0.618), p=0.610, for the comparison of the image evaluation with smart glasses and a conventional monitor. This means that no significant difference was detected for the evaluation of image quality in this pilot data.
Conclusion: There were promising early results for the image quality provided by smart glasses in comparison to a conventional monitor. A larger-scale study, also considering dynamic imaging, is now required.
Limitations: n/a
Ethics: Application HST1819-279 approved University of Salford.
Funding: CoRIPS Student Research Award.
RPS 1409a-3
Endovascular simulation training: a tool to increase enthusiasm for interventional radiology among medical students
Purpose: Interventional radiology (IR) is a growing field but is underrepresented in most medical school curricula. We tested whether endovascular simulator training improves attitudes towards IR among medical students.
Methods: We conducted this prospective study at two university medical centres, where 4th-year medical students completed a 90-minute IR course. The class consisted of a theoretical part and a practical part, involving endovascular simulators. Using smartphones/tablets, students completed questionnaires before the course, after the theoretical part, and after the practical part. On a 7-point Likert scale, they rated their interest in IR, knowledge about IR, the attractiveness of IR, and the likelihood to consider IR as a subspecialty. We used a crossover design to prevent position-effect bias.
Results: The seminar/simulator parts led to higher scores for all items compared to baseline: interest in IR (pre-course 5.2 vs post-seminar/post-simulator 5.5/5.7), knowledge of IR (pre-course 2.7 vs post-seminar/post-simulator 5.1/5.4), attractiveness in IR (pre-course 4.6 vs post-seminar/post-simulator 4.8/5.0), and the likelihood of choosing IR as a subspecialty (pre-course 3.3 vs post-seminar/post-simulator 3.8/4.1). Although the seminar and simulator both led to a significant improvement, the effect was significantly stronger for the simulator training compared to the seminar for all items (all p<0.05).
Conclusion: Endovascular simulator training in medical school significantly increases students' interest in IR, knowledge about IR, positive attitude toward IR, and the likelihood of potentially choosing IR as a subspecialty. Implementing dedicated IR courses that include practical simulator training might ease recruitment problems in the field.
Limitations: We minimised response bias by using an anonymous, untraceable survey design and ad-hoc completion of each questionnaire during the course.
Ethics: n/a
Funding: No funding was received for this work.
RPS 1409a-4
Augmented reality in training: can CT-guided intervention be simulated accurately?
Purpose: Computed tomography (CT)-guided interventions are taught across the world mostly using a traditional mentored approach on real patients. However, it is well established that simulation is a valuable training tool in medicine. This project assessed the feasibility and acceptance of replicating a CT-guided intervention using a bespoke software application within an augmented reality head-mounted display (ARHMD): the Microsoft HoloLens.
Methods: A bespoke application was written to simulate the process of performing a CT-guided procedure using augmented reality. Virtual patients were generated using CT datasets obtained from the cancer imaging archive. A mesh of a virtual patient was projected into the field of view of the operator and a virtual CT slice simulating the needle position generated on voice command. In order to provide tactile feedback, a mock biopsy phantom was made using agar jelly. ChArUco markers were used to track both the needle and phantom using RGB cameras built into the ARHMD.
The application was trialled by senior international radiologists and radiology registrars-in-training with a structured feedback questionnaire evaluating face validity and technical aspects.
Results: Good feedback was received from participants regarding realism, usability, and the accuracy of the application.
Conclusion: The study showed it is possible to replicate a CT-guided procedure with augmented reality and that this could be used as a training tool.
Limitations: There is no comparison made to traditional CT training techniques, although a further study will address this. A limited CT dataset was used to simulate patient subjects and this could be increased with further study.
Ethics: The CT datasets from the cancer imaging archive have ethical approval for re-use. No other ethical approval was required.
Funding: No funding was received for this work.
RPS 1409a-5
RDIM software for patient peak skin dose assessment: comparison with radiochromic film measurements
Purpose: To evaluate the accuracy of the algorithm for calculating the skin dose distribution in interventional radiology procedures, provided by the radiation dose index monitoring software NEXO[DOSE]® (Bracco Injeneering SA, Lausanne).
Methods: To obtain the skin dose distribution, the software uses exposure parameters taken from the radiation dose structured report (primary/secondary angles, source-to-isocenter distance, kV, Kerma-Area Product (KAP), air-Kerma at interventional reference point, and additional filters), angiographic system information (table attenuation and KAP correction factor), and other factors, such as the backscatter factor and ratio of mass-energy absorption coefficients. The software had been previously validated on a geometrical phantom. GafChromic® XR-RV3 films were positioned under the patient?s back to evaluate the software accuracy in clinical conditions. The interventional procedures (18 cases including prostatic artery embolisation, uterine fibroid embolisation, transjugular intrahepatic portosystemic shunt, and transarterial chemoembolisation) were performed with two Philips Integris Allura FD20 and a Siemens Artis Zeego.
Results: The peak skin dose (PSD) values were in a range from 0.2 Gy to 10 Gy. The differences between estimated and measured PSD were lower than 25%, except in one case where a discrepancy of 65% was probably due to an uncorrected geometric evaluation or to the film positioning. The mean deviation is 0.7%±20.6%.
Conclusion: We observed a good correlation (r=0.980, p<0.0001) between film measurements and software estimates. This study suggests that NEXO[DOSE]® software can be considered as a valuable dose calculation tool to optimise existing practices and monitor the follow-up required for patients who have received high doses, without using radiochromic films which are expensive and time-consuming.
Limitations: The analysis of a limited number of cases due to incorrect film positioning.
Ethics: n/a
Funding: No funding was received for this work.
RPS 1409a-6
Monte Carlo study of 3D stray radiation during interventional procedures
Purpose: In interventional medical procedures, other than the highly important issue of optimising image quality and patient exposure in use of the primary beam, there remains a continuing need for the study of staff exposures from the scattered radiation. Herein, an investigation is made of the 3D stray radiation distribution, the simulation being made of a realistic interventional scenario through the use of the Monte Carlo code Geant4 (version 10.3).
Methods: The simulation was conducted based on the HDRK-Man computational phantom and a GE Infinia 3/8? C-arm machine, focusing on the effect of variation of kVp and field of view (FoV) on the scattered particles spatial distribution. Scatter fraction distributions were simulated for x-ray tube outputs (and half-value layers, HVL) of 60 kVp (2.3 mm Al), 80kVp (3.2 mm Al), and 120 kVp (4.3 mm Al), and FoV of 15, 20, 25, and 30 cm. The distributions are obtained for different height levels, corresponding to the lens of the eye, lung and prostate, and all radiosensitive organs.
Results: At fixed FoV, results reveal an inverse relationship between ESAK and kVp. A change in kVp from 60 to 80 has a greater effect than from 80 to 120. For a change in FoV at fixed kVp, the scatter fraction remains constant. For a given value of FoV, ESAK is seen to increases with a decrease in kVp, supporting existing literature.
Conclusion: The typically adopted locations of the various members of staff during interventions, in accordance with their role, is found to be an optimal choice. From such findings, we urge for the implementation of appropriate in-house protocols in seeking to mitigate the potential deleterious effects of radiation to members of staff.
Limitations: n/a
Ethics: n/a
Funding: No funding was received for this work.
RPS 1409a-7
The eye lens dose of the interventionalist: measurement in practice
Purpose: Early in 2018, the new eye lens dose limit of 20 mSv per year for occupational exposure to ionising radiation was implemented in the European Union. Dutch guidelines state that monitoring is compulsory above an expected eye lens dose of 15 mSv/year. In this study, we assess whether the eye lens dose of interventionalists in the Máxima Medical Centre, the Netherlands, would exceed 15 mSv/year and whether the measured eye lens dose measurements can be individually related to regular personal dosimeter measurements.
Methods: The eye lens dose, Hp( 3), of interventional radiologists (n=2), cardiologists (n=2), and vascular surgeons (n=3) was measured during six months, using thermoluminescence dosimeters (Mirion dosimetry services) on the forehead. Simultaneously, the surface dose, Hp (0.07), and whole-body dose, Hp (10), were measured using regular dosimeters outside the lead skirt at chest level. The dosimeters were simultaneously refreshed every four weeks. The observed dose data was extrapolated to one year to check compliance with the year limit.
Results: A clear relation was observed between the two dosimeters: Hp(3)?0,25 Hp(0,07). The extrapolated year dose for the eye lens did not exceed 15 mSv for any of the interventionalists (average 3 to 10 studies/month).
Conclusion: The eye lens dose can be monitored indirectly through regular dosimeter at chest level. Additionally, all interventionalists remain below the dose limit and compulsory monitoring limit for the eye lens dose. We cannot generalise our findings to other hospitals because of too many variables involved, such as procedure type, the orientation of the tube, and the position of the interventionalist. Nevertheless, a limited monitoring period can give substantial information on the yearly eye lens dose.
Limitations: Findings are not generalisable to other hospitals due to many variables.
Ethics: n/a
Funding: No funding was received for this work.
RPS 1409a-8
Endovascular technologies for radiation oncology: how to protect patients from potential bleeding during radiotherapy and proton therapy in cases of vessel tumour invasion
Purpose: To evaluate individual approaches of different endovascular techniques for bleeding prevention during conventional external beam or proton radiotherapy in patients with a pelvic tumour mass and vessel invasion.
Methods: This is an ongoing case study. In 2018-2019, 3 patients (colorectal cancer, chondrosarcoma, and locoregional ovarian cancer) with vessel tumour invasion were included. 1 patient has an invasion into the internal iliac vein (IIV) and 2 have an invasion into external and common iliac veins (ECIV). Vein involvement was confirmed by CT and MR-angiography and conventional contrast angiography. Venous tumour invasion was characterised by a high bleeding risk during irradiation. Every case was discussed by the tumour board with intervention radiologists. The IIV patient underwent selective vein embolisation by coils and the ECIV patients underwent endovascular stenting by stent graft. Radiation therapy (2 external beam VMAT, 1-proton therapy) was performed.
Results: All patients were irradiated without bleeding complications. 2 patients with stent-grafts during the first follow-up (months 3) had no signs of venous insufficiency i.e. endovascular devices also prevent vein occlusion in postradiation period. For outcome tracking the individual, a program was developed; visits and control MRI at 3, 6, and 12 months and angiography on demand (by the decision of an interventional radiologist). From an oncology perpective, these patients are still under surveillance.
Conclusion: Internal bleeding during radiotherapy is a rare but potentially life-threatening complication. Multidisciplinary discussion with an interventional radiologist allows identification and risk minimisation endovascular technologies. Coil embolisation may be useful for internal iliac vein tumour invasion and angioplasty and stenting by stent-graft for external and common iliac vein involvement.
Limitations: A small number of subjects. Heterogeneous data sampling. The uncommon incidence of these types of clinical cases.
Ethics: The study was approved by a local ethical board.
Funding: No funding was received for this work.
RPS 1409a-9
Monte Carlo study of scattered radiation during CBCT studies
Purpose: Staff exposure to radiation during an interventional procedure with cone-beam CT (CBCT) can be higher than standard interventional fluoroscopic studies. This dose is due to scattered radiation during the operation. In this work, we study the origin and the impact of scatter using a GATE (GEANT4 application for tomographic emission) simulation toolkit. First, we validate a numerical model of a C-arm x-ray system from Siemens named ARTIS ZEEGO by the estimation of the computed tomography dose index (CTDI) using two polymethylmethacrylate (PMMA) phantoms. In addition, we present the validation of the GATE-modelled x-ray tube named MEGALIX Cat Plus by comparing the simulated energy spectrum with the calculated one by the SpekCalc software.
Methods: Radiation doses (CTDI) were measured using PMMA head and body phantoms with diameters of 16 and 32 cm, respectively, and a height of 15 cm. Both phantoms contain five different positions (at centre and 3h, 6h, 9h, and 12h positions in the phantoms). Radiation measurements were performed at the 5 holes using a 100 mm long pencil chamber.
Results: For various voltage (kVp) levels of the x-ray tube, the results of simulated x-ray spectrums show a good agreement with calculated ones (SpekCalc). A difference in the K-characteristic x-ray intensity was observed. The relative difference between simulated and measured CTDI value for Siemens ARTIS ZEEGO at different kVp were less than 5%. Simulations demonstrated the distribution of scatter in the equipment and highlighted areas of potential high occupational doses.
Conclusion: In this study, we demonstrated the feasibility of modelling a complete CBCT study from the x-ray tube to the absorbed dose and the scattered one.
Limitations: A limitation in Monte Carlo tools and a lack of details about some CBCT components.
Ethics: n/a
Funding: No funding was received for this work.
RPS 1409a-10
Leveraging technology to build an interventional oncology practice
Purpose: Telemedicine has been utilised in primary care to increase access for patients. As the patient acceptance of this practice has grown, specialists have also begun to utilise telehealth visits. We tested the feasibility of starting an IR TeleHealth practice and studied the impact with a focus on days from IR referral to consult and from IR referral to biopsy.
Methods: Telehealth visits were performed either by a physician or advanced practice provider at a single academic medical centre. The total patient encounters were analysed from 2017-2019. Visit types were categorised by standard documentation criteria. Time saved by the patient and physician not having to travel between locations was studied. Days from IR referral to consult and days from IR referral to biopsy were studied.
Results: In our experience, there were 325 telehealth encounters. Patients saved a total of $10,524 in travel costs and 279 hours of travel time. A total of 521 hours of travel time was saved by physicians and a total of $76,000 was saved by the practice. Days from IR referral to a clinic consult decreased from 2.7 days to 0.33 days and days from IR referral to biopsy decreased from 17.2 days to 12.2 days.
Conclusion: Leveraging telehealth can increase access to care for patients and allow for more efficient use of physician resources. In addition, telehealth could decrease the time from the referral to the initial office consult and could decrease both the time to the clinic consultation and the IR procedure since many of these patients could potentially be seen on the same day as the referral.
Limitations: The equipment cost and regulations/compliance issues.
Ethics: n/a
Funding: No funding was received for this work.
RPS 1409a-11
Does interventional radiology undergraduate exposure hold the key to workforce shortage? A multicentre/cross-sectional study in the United Kingdom
Purpose: Interventional radiology (IR) is an evolving sub-speciality, although its representation in the undergraduate curriculum is not. This has prompted the cardiovascular and interventional radiology society of Europe (CIRSE) to introduce an undergraduate curriculum. With a shortage of 500 IR consultants, we aim to assess IR representation in the undergraduate curriculum across the United Kingdom.
Methods: An 18-question questionnaire, influenced by the CIRSE undergraduate curriculum, was circulated across 18 hospitals in the United Kingdom. Recently graduated doctors were targeted to assess their understanding of IR given that they would have theoretically been exposed to the entire undergraduate curriculum and only have limited postgraduate experience.
Results: 280 replies were received. One-third of the cohort demonstrated poor exposure to general radiology, although this figure soared to 76% for IR. Only 13% of the respondents experienced a dedicated IR section in their undergraduate curriculum. Only two students were aware of international/national IR undergraduate curricula. More than 80% of respondents did not consider a career in radiology for various reasons, with 30% citing a lack of exposure. 40% of junior doctors were not aware of radiation exposure in IR. Similarly, less than half of the cohort correctly identified both the training route for IR and the imaging modalities used. Nonetheless, 80% of the respondents thought coronary stenting was being performed by IRs. Finally, the majority of the cohort welcomed radiology attachments and IR lectures as preferred teaching methods, the inclusion of IR undergraduate curriculum, and a two-week postgraduate exposure.
Conclusion: Despite current efforts, radiology, especially IR, is still falling behind in undergraduate curriculum representation. This study confirms that improved IR undergraduate exposure is a key factor in tackling national shortages of IRs.
Limitations: National, not international, study.
Ethics: n/a
Funding: No funding was received for this work.


Viktor Bérczi (Hungary)

European Society of Radiology

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