Science-informed Policy Making for Protecting People and the Environment from Radiation

ABSTRACT

The process to arrive at the radiation protection practices of today to protect workers, patients, and the public, including sensitive populations, has been a long and deliberative one. This paper presents an overview of the US Environmental Protection Agency's (US EPA) responsibility in protecting human health and the environment from unnecessary exposure to radiation. The origins of this responsibility can be traced back to early efforts, a century ago, to protect workers from x rays and radium. The system of radiation protection we employ today is robust and informed by the latest scientific consensus. It has helped reduce or eliminate unnecessary exposures to workers, patients, and the public while enabling the safe and beneficial uses of radiation and radioactive material in diverse areas such as energy, medicine, research, and space exploration. Periodic reviews and analyses of research on health effects of radiation by scientific bodies such as the National Academy of Sciences, National Council on Radiation Protection and Measurements, United Nations Scientific Committee on the Effects of Atomic Radiation, and the International Commission on Radiological Protection continue to inform radiation protection practices while new scientific information is gathered. As a public health agency, US EPA is keenly interested in research findings that can better elucidate the effects of exposure to low doses and low dose rates of radiation as applicable to protection of diverse populations from various sources of exposure. Professional organizations such as the Health Physics Society can provide radiation protection practitioners with continuing education programs on the state of the science and describe the key underpinnings of the system of radiological protection. Such efforts will help equip and prepare radiation protection professionals to more effectively communicate radiation health information with their stakeholders.

A Revised System of Radiological Protection Is Needed

ABSTRACT

The system of radiological protection has been based on linear no-threshold theory and related dose-response models for health detriment (in part related to cancer induction) by ionizing radiation exposure for almost 70 y. The indicated system unintentionally promotes radiation phobia, which has harmed many in relationship to the Fukushima nuclear accident evacuations and led to some abortions following the Chernobyl nuclear accident. Linear no-threshold model users (mainly epidemiologists) imply that they can reliably assess the cancer excess relative risk (likely none) associated with tens or hundreds of nanogray (nGy) radiation doses to an organ (e.g., bone marrow); for 1,000 nGy, the excess relative risk is 1,000 times larger than that for 1 nGy. They are currently permitted this unscientific view (ignoring evolution-related natural defenses) because of the misinforming procedures used in data analyses of which many radiation experts are not aware. One such procedure is the intentional and unscientific vanishing of the excess relative risk uncertainty as radiation dose decreases toward assigned dose zero (for natural background radiation exposure). The main focus of this forum article is on correcting the serious error of discarding risk uncertainty and the impact of the correction. The result is that the last defense of the current system of radiological protection relying on linear no-threshold theory (i.e., epidemiologic studies implied findings of harm from very low doses) goes away. A revised system is therefore needed.

Replace the Linear No-threshold Model with a Risk-informed Targeted Approach to Radiation Protection

ABSTRACT

The linear no-threshold (LNT) model may be useful as a simple basis for developing radiation protection regulations and standards, but it bears little resemblance to scientific reality and is probably overly conservative at low doses and low dose rates. This paper is an appeal for a broader view of radiation protection that involves more than just optimization of radiation dose. It is suggested that the LNT model should be replaced with a risk-informed, targeted approach to limitation of overall risks, which include radiation and other types of risks and accidents/incidents. The focus should be on protection of the individual. Limitation of overall risk does not necessarily always equate to minimization of individual or collective doses, but in some cases it might. Instead, risk assessment (hazards analysis) should be performed for each facility/and or specific job or operation (straightforward for specialized work such as radiography), and this should guide how limited resources are used to protect workers and the public. A graded approach could be used to prioritize the most significant risks and identify exposure scenarios that are unlikely or non-existent. The dose limits would then represent an acceptable level of risk, below which no further reduction in dose would be needed. Less resources should be spent on ALARA and tracking small individual and collective doses. Present dose limits are thought to be conservative and should suffice in general. Two exceptions are possibly the need for a lower (lifetime) dose limit for lens of the eye for astronauts and raising the public limit to 5 mSv y -1 from 1 mSv y -1 . This would harmonize the public limit with the current limit for the embryo fetus of the declared pregnant worker. Eight case studies are presented that emphasize how diverse and complex radiation risks can be, and in some cases, chemical and industrial risks outweigh radiation risks. More focus is needed on prevention of accidents and incidents involving a variety of types of risks. A targeted approach is needed, and commitments should be complied with until they are changed or exemptions are granted. No criticism of regulators or nuclear industry personnel is intended here. Protection of workers and the public is everyone's goal. The question is how best to accomplish that.

Reducing radiation exposure and costs: CT body scout views with an enhanced protocol versus conventional radiography after shunt surgery

OBJECTIVE

Ventriculoperitoneal shunt implantation has become standard treatment for cerebrospinal fluid diversion, besides endoscopic third ventriculostomy for certain indications. Postoperative X-ray radiography series of skull, chest and abdomen combined with cranial CT are obtained routinely in many institutions to document the shunt position and valve settings in adult patients. Measures to reduce postoperative radiation exposure are needed, however, there is only limited experience with such efforts. Here, we aim to compare routine postoperative cranial CT plus conventional radiography series (retrospective arm) with cranial CT and body scout views only (prospective arm) concerning both diagnostic quality and radiation exposure.

PATIENTS AND METHODS

After introduction of an enhanced CT imaging protocol, routine skull and abdomen radiography was no longer obtained after VP shunt surgery. The image studies of 25 patients with routine postoperative cranial CT and conventional radiography (retrospective arm of study) were then compared to 25 patients with postoperative cranial CT and CT body scout views (prospective arm of study). Patient demographics such as age, sex and primary diagnosis were collected. The image quality of conventional radiographic images and computed tomography scout views images were independently analyzed by one neurosurgeon and one neuroradiologist.

RESULTS

There were no differences in quality assessments according to three different factors determined by two independent investigators for both groups. There was a statistically significant difference, however, between the conventional radiography series group and the CT body scout view imaging group with regard to radiation exposure. The effective dose estimation calculation yielded a difference of 0.05 mSv (two-tailed t-test, p = 0.044) in favor of CT body scout view imaging. Furthermore, the new enhanced protocol resulted in a reduction of cost and the use of human resources.

CONCLUSION

CT body scout view imaging provides sufficient imaging quality to determine shunt positioning and valve settings. With regard to radiation exposure and costs, we suggest that conventional postoperative shunt series may be abandoned.

Use of the flat panel detector fluoroscope reduces radiation exposure during periacetabular osteotomy

The Periacetabular Osteotomy is a technically demanding procedure that requires precise intraoperative evaluation of pelvic anatomy. Fluoroscopic images pose a radiation risk to operating room staff, scrubbed personnel, and the patient. Most commonly, a Standard Fluoroscope with an Image Intensifier is used. Our institution recently implemented the novel Fluoroscope with a Flat Panel Detector. The purpose of this study was to compare radiation dosage and accuracy between the two fluoroscopes. A retrospective review of a consecutive series of patients who underwent Periacetabular Osteotomy for symptomatic hip dysplasia was completed. The total radiation exposure dose (mGy) was recorded and compared for each case from the standard fluoroscope (n = 27) and the flat panel detector (n = 26) cohorts. Lateral center edge angle was measured and compared intraoperatively and at the six-week postoperative visit. A total of 53 patients (96% female) with a mean age and BMI of 17.84 (± 6.84) years and 22.66 (± 4.49) kg/m2 (standard fluoroscope) and 18.23 (± 4.21) years and 21.99 (± 4.00) kg/m2 (flat panel detector) were included. The standard fluoroscope averaged total radiation exposure to be 410.61(± 193.02) mGy, while the flat panel detector averaged 91.12 (± 49.64) mGy (p < 0.0001). The average difference (bias) between intraoperative and 6-week postoperative lateral center edge angle measurement was 0.36° (limits of agreement: - 3.19 to 2.47°) for the standard fluoroscope and 0.27° (limits of agreement: - 2.05 to 2.59°) for the flat panel detector cohort. Use of fluoroscopy with flat panel detector technology decreased the total radiation dose exposure intraoperatively and produced an equivalent assessment of intraoperative lateral center edge angle. Decreasing radiation exposure to young patients is imperative to reduce the risk of future comorbidities.

177Lu-Dotatate administration using an infusion pump or a peristaltic pump: comparison of two methods

OBJECTIVES

177Lu-oxodotreotide (Lutathera) is an intravenous peptide receptor radionuclide therapy to treat unresectable metastatic digestive neuroendocrine tumours. The recommended method for Lutathera administration is gravity infusion; however, other appropriate and safe techniques are possible. This work compares two infusion methods from a medico-economic, radiation protection, efficiency and practicality point of view.

METHODS

Two infusion methods were studied, either involving a volumetric infusion pump (method 1) or a peristaltic pump (method 2). For each method, the mean residual activity per vial and the mean injection time were compared. Occupational radiation exposure was measured. The cost of initial equipment and consumables for one administration was determined. Feedback from operators and past incidents during injections were collected through a survey.

RESULTS

Three operators performed 219 Lutathera injections over 70 months: 60.7% (133) with method 1 and 39.3% (86) with method 2. After infusion, the mean residual activity in vial was 124.3±16.9 MBq with method 1 and 80.9±19.3 MBq with method 2 (34.9% decrease). The average administration time was 41±7.2 min with method 1 and 39±8.5 min with method 2. Occupational exposures obtained with both methods were very low and quite similar. Method 1 required an initial investment of 1165.8 US$ plus 4.0 US$ of supplies for each administration. Initial investment for method 2 was comparable (1261.4 US$) but supplies cost per administration was higher (12.5 US$). Two major incidents were recorded with method 1 and none with method 2. From operators' experience, method 2 felt safer and more suitable.

CONCLUSIONS

Method 2 appeared to be convenient and secure, despite a higher cost per injection. It could also be applied to new radioligand therapies such as 177Lu-PSMA or 225Ac-Dotatate.

The effect of Fiber Optic RealShape technology on the reduction of radiation during complex endovascular surgery

OBJECTIVE

Despite the advantages that fenestrated endovascular aortic repair has over open repair, it is accompanied by the consequence of radiation exposure, which can result in long-term complications for both the patient and surgical staff. Fiber Optic RealShape (FORS) technology is a novel advancement that uses emitted light from a fiber optic wire and enables the surgeon to cannulate vessels in real time without live fluoroscopy. This technology has been implemented at select centers to study its effectiveness for cannulation of target vessels and its impact on procedural radiation.

METHODS

We collected prospective data on physician-modified endograft (PMEG) cases before and after the introduction of FORS technology. FORS PMEGs were matched with up to three conventional fluoroscopy cases by number of target vessels, inclusion of a bifurcated device below, aneurysm extent, and patient body mass index. The procedural radiation parameters were compared between these cohorts. Within the FORS cohort, we analyzed the rate of successful target vessel cannulation for all cases done with this technology (including cases other than PMEGs), and we compared the radiation between the cannulations using only FORS with those that abandoned FORS for conventional fluoroscopy.

RESULTS

Nineteen FORS PMEGs were able to be matched to 45 conventional fluoroscopy cases. Procedures that used FORS technology had significantly reduced total air kerma (527 mGy vs 964 mGy), dose area product (121 Gy∗cm2 vs 186 Gy∗cm2), fluoroscopy dose (72.1 Gy∗cm2 vs 132.5 Gy∗cm2), and fluoroscopy time (45 minutes vs 72 minutes). There was no difference in procedure length, total contrast, or digital subtraction angiography. Within FORS cases, 66% of cannulations were completed using only FORS. Cannulations using only FORS had significant reduction of navigation air kerma (5.0 mGy vs 26.5 mGy), dose area product (1.2 Gy∗cm2 vs 5.1 Gy∗cm2), and fluoroscopy time (0.6 minutes vs 2.3 minutes) compared with cannulations abandoning FORS for conventional fluoroscopy.

CONCLUSIONS

This study demonstrates the advantages of FORS for total procedural radiation as well as during individual cannulation tasks. The implementation of FORS for target vessel catheterization has the potential to decrease the total degree of radiation exposure for the patient and surgical staff during complex endovascular aortic surgeries.

Halved contrast medium dose coronary dual-layer CT-angiography - phantom study of tube current and patient characteristics

Virtual mono-energetic images (VMI) using dual-layer computed tomography (DLCT) enable substantial contrast medium (CM) reductions. However, the combined impact of patient size, tube voltage, and heart rate (HR) on VMI of coronary CT angiography (CCTA) remains unknown. This phantom study aimed to assess VMI levels achieving comparable contrast-to-noise ratio (CNR) in CCTA at 50% CM dose across varying tube voltages, patient sizes, and HR, compared to the reference protocol (100% CM dose, conventional at 120 kVp). A 5 mm artificial coronary artery with 100% (400 HU) and 50% (200 HU) iodine CM-dose was positioned centrally in an anthropomorphic thorax phantom. Horizontal coronary movement was matched to HR (at 0, < 60, 60-75, > 75 bpm), with varying patient sizes simulated using phantom extension rings. Raw data was acquired using a clinical CCTA protocol at 120 and 140 kVp (five repetitions). VMI images (40-70 keV, 5 keV steps) were then reconstructed; non-overlapping 95% CNR confidence intervals indicated significant differences from the reference. Higher CM-dose, reduced VMI, slower HR, higher tube voltage, and smaller patient sizes demonstrated a trend of higher CNR. Regardless of HR, patient size, and tube voltage, no significant CNR differences were found compared to the reference, with 100% CM dose at 60 keV, or 50% CM dose at 40 keV. DLCT reconstructions at 40 keV from 120 to 140 kVp acquisitions facilitate 50% CM dose reduction for various patient sizes and HR with equivalent CNR to conventional CCTA at 100% CM dose, although clinical validation is needed.

The addition of a leaded arm sleeve to leaded aprons further decreases operator upper outer quadrant chest wall radiation dose during fluoroscopically guided interventions

OBJECTIVE

Breast cancer most commonly occurs in the upper outer quadrant (UOQ) chest wall (CW). The effectiveness of routine leaded aprons to protect this region of the body in interventionalists during fluoroscopically guided interventions (FGIs) is unknown. Given the high lifetime attributable risks of prolonged occupational exposure to ionizing radiation and the increasing number of practicing female vascular surgeons and interventionalists, we sought to determine if the use of a leaded arm shield would offer additional protection to the lateral CW and axilla in operators compared with routine leaded aprons.

METHODS

Effectiveness of leaded sleeves in attenuating radiation dose to the axilla and UOQ was evaluated in clinical practice and simulated scenarios. In the clinical setting, optically stimulated luminescence nanoDot detectors were placed at the UOQ lateral CW position, both over and under a standard leaded apron vest with and without the addition of an antimony/bismuth Enviro-Lite sleeve on two vascular surgeons performing FGIs. In the simulation, nanoDots were similarly placed on an anthropomorphic phantom positioned to represent a primary operator performing right femoral access. Fluorography was performed on 12-inch-thick acrylic scatter phantom at 80 kVp for an exposure of 3 Gy reference air kerma. Experiments were done with and without the sleeve. Paired Wilcoxon and χ2 tests were performed to identify the statistical significance of radiation attenuation.

RESULTS

Operator UOQ CW dose was measured during 61 FGIs: 33 cases (54%) with and 28 cases (46%) without the sleeve. Median procedure reference air kerma and fluoroscopy time was 180 mGy (interquartile range [IQR], 85-447 mGy) and 21 minutes (IQR, 11-39 minutes) when the sleeve was worn vs 100 mGy (IQR, 67-270 mGy) and 11 minutes (IQR, 6.3-25 minutes) without the sleeve. Radiation dose to the operator's UOQ was reduced by 96% (IQR, 85%-96%) when the sleeve was present and by 62% (IQR, 44%-82%; P < .001) without the sleeve. In the simulated setting, the sleeve reduced the radiation dose to the UOQ compared with the apron alone (96% vs 67%; P < .001).

CONCLUSIONS

Routine leaded aprons do attenuate the majority of UOQ chest wall radiation dose; however, the addition of a lead-equivalent sleeve further significantly reduces this dose. Because this area of the body has a high incidence of cancer formation, additional protection, especially to female interventionalists, seems prudent. Vascular surgeons should consider using a protective sleeve with their personal protective equipment when performing complex fluoroscopically guided procedures.

[The Need for Lens Radiation Protection for Healthcare Provider in Open and Internal Fixation of the Hip Joint]

Increased occupational exposure of radiation workers is a major problem during open reduction and internal fixation (ORIF) of the hip joint, as the surgeon's eye lens is in close proximity to the patient and the X-ray tube. The purposes of this study were to clarify the occupational exposure of radiation workers during ORIF of the hip joint and to examine the need for radiation protection measures. The radiation exposure of radiation workers was evaluated by making an airborne dose distribution map using phantom experiments. The radiation goggles attached with a small optically stimulated luminescence dosimeter were used in clinical practice to measure the lens dose received by the surgeon, and the necessity of radiation goggles was examined. The airborne dose distribution in ORIF of the hip joint showed a wider area of high dose rate during axial fluoroscopy of the femoral neck than during posterior-anterior fluoroscopy. In axial fluoroscopy of the femoral neck, the surgeon was always in the high dose rate range of 10 µGy/min or higher, the nurses were in the dose rate range of 4 to 10 µGy/min, and the radiologic technologists were in the dose rate range of 0.5 µGy/min or lower. The maximum 3 mm dose equivalent to the surgeon per case was 0.38 mSv. In contradiction, radiation goggles were useful in ORIF because they provided approximately 60% shielding. It is advisable to work with radiation goggles to avoid cataracts.

Comparative analysis of radiation exposure in robot-assisted total knee arthroplasty using popular robotic systems

Robotic-assisted TKA (RATKA) is a rapidly emerging technique that has been shown to improve precision and accuracy in implant alignment in TKA. Robotic-assisted TKA (RATKA) uses computer software to create a three-dimensional model of the patient's knee. Different types of preoperative imaging, including radiographs and CT scans, are used to create these models, each with varying levels of radiation exposure. This study aims to determine the radiation dose associated with each type of imaging used in RATKA, to inform patients of the potential risks. A retrospective search of our clinical radiology and arthroplasty database was conducted to identify 140 knees. The patients were divided into three groups based on the type of preoperative imaging they received: (1) CT image-based MAKO Protocol, (2) Antero-posterior long leg alignment films (LLAF), (3) standard AP, lateral, and skyline knee radiographs. The dose of CT imaging technique for each knee was measured using the dose-length product (DLP) with units of mGycm2, whereas the measurement for XRAY images was with the dose area product (DAP) with units of Gycm2. The mean radiation dose for patients in the CT (MAKO protocol) image-based group was 1135 mGy.cm2. The mean radiation dose for patients in the LLAF group was 3081 Gycm2. The mean radiation dose for patients undergoing knee AP/lateral and skyline radiographs was the lowest of the groups, averaging 4.43 Gycm2. Through an ANOVA and post hoc analysis, the results between groups was statistically significant. In this study, we found a significant difference in radiation exposure between standard knee radiographs, LLAF and CT imaging. Nonetheless, the radiation dose for all groups is still within acceptable safety limits.

Trends in the use of radiation protection and radiation exposure of European endourologists: a prospective trial from the EULIS-YAU Endourology Group

INTRODUCTION

Due to the radiation exposure for the urology staff during endourology, our aim was to evaluate the trends of radiation protection in the operation room by endourologists from European centers and to estimate their annual radiation.

METHODS

We conducted a multicenter study involving experienced endourologists from different European centers to evaluate whether the protection and threshold doses recommended by the International Commission on Radiation Protection (ICRP) were being followed. A 36-question survey was completed on the use of fluoroscopy and radiation protection. Annual prospective data from chest, extremities, and eye dosimeters were collected during a 4-year period (2017-2020).

RESULTS

Ten endourologists participated. Most surgeons use lead aprons and thyroid shield (9/10 and 10/10), while leaded gloves and caps are rarely used (2/10 both). Six out of ten surgeons wear leaded glasses. There is widespread use of personal chest dosimeters under the apron (9/10), and only 5/10 use a wrist or ring dosimeter and 4 use an eye dosimeter. Two endourologists use the ALARA protocol. The use of ultrasound and fluoroscopy during PCNL puncture was reported by 8 surgeons. The mean number of PCNL and URS per year was 30.9 (SD 19.9) and 147 (SD 151.9). The mean chest radiation was 1.35 mSv per year and 0.007 mSv per procedure. Mean radiation exposure per year in the eyes and extremities was 1.63 and 11.5 mSv.

CONCLUSIONS

Endourologists did not exceed the threshold doses for radiation exposure to the chest, extremities and lens. Furthermore, the ALARA protocol manages to reduce radiation exposure.

Role of Laser Pointer in Budgeting Fluoroscopy-Time and Radiation Exposure

BACKGROUND

Literature on radiation exposure with use of the mini C-arm and value of having built-in laser guidance is limited. The purpose of this study was to determine whether laser guidance use on a mini C-arm fluoroscopy unit can reduce radiation exposure.

METHODS

Surgeons (N = 25) performed the same simulated surgical task, which involved obtaining "perfect circle" views of 2 cannulated screws placed into a cadaveric wrist, done with and without C-arm laser guidance. The testing order was randomized. Main outcomes were time to complete the task, number of shots required to complete the task, number of blank shots taken, radiation exposure, total dose area product (DAP), and total exposure time.

RESULTS

Laser guidance significantly reduced the percentage of surgeons who took blank shots, from 88% of the group without the laser to 12% of the group with the laser, and decreased the total average blank shots in the group from 3.5 to 0.1. While we found laser guidance led to shorter time to complete the task, decreased shots taken, and decreased exposure time and DAP, these findings only approached significance.

CONCLUSION

While debate continues regarding whether mini or standard C-arm is safest, it is clear that decreasing the overall number of exposures limits potential adverse effects. Our study demonstrated that when using a mini C-arm, laser guidance decreases the number of exposures required to capture an image. These findings warrant a larger study to define the specific exposure savings and indicate potential benefit of mini C-arm use with laser guidance.

Virtual Injection Software Reduces Radiation Exposure and Procedural Time of Prostatic Artery Embolization Performed with Cone-Beam CT

PURPOSE

To evaluate the impact of virtual injection software (VIS) use during cone-beam computed tomography (CT)-guided prostatic artery embolization (PAE) on both patient radiation exposure and procedural time.

MATERIALS AND METHODS

This institutional review board (IRB)-approved comparative retrospective study analyzed the treatment at a single institution of 131 consecutive patients from January 2020 to May 2022. Cone-beam CT was used with (Group 1, 77/131; 58.8%) or without VIS (Group 2, 54/131, 41.2%). Radiation exposure (number of digital subtraction angiography [DSA] procedures), dose area product (DAP), total air kerma (AK), peak skin dose (PSD), fluoroscopy time (FT), and procedure time (PT) were recorded. The influences of age, body mass index, radial access, and use of VIS were assessed.

RESULTS

In bivariate analysis, VIS use (Group 1) showed reduction in the number of DSA procedures (8.6 ± 3.7 vs 16.8 ± 4.3; P < .001), DAP (110.4 Gy·cm2 ± 46.8 vs 140.5 Gy·cm2 ± 61; P < .01), AK (642 mGy ± 451 vs 1,150 mGy ± 637; P = .01), PSD (358 mGy ± 251 vs 860 mGy ± 510; P = .001), FT (35.6 minutes ± 15.4 vs 46.6 minutes ± 20; P = .001), and PT (94.6 minutes ± 41.3 vs 115.2 minutes ± 39.6, P = .005) compared to those in Group 2. In multivariate analysis, AK, PSD, FT, and PT reductions were associated with VIS use (P < .001, P < .001, P = .001, and P = .006, respectively).

CONCLUSIONS

The use of VIS during PAE performed under cone-beam CT guidance led to significant reduction in patient radiation exposure and procedural time.

Use of Lung Ultrasound in Reducing Radiation Exposure in Neonates with Respiratory Distress: A Quality Management Project

Background and Objectives: Our quality management project aims to decrease by 20% the number of neonates with respiratory distress undergoing chest radiographs as part of their diagnosis and monitoring. Materials and Methods: This quality management project was developed at Life Memorial Hospital, Bucharest, between 2021 and 2023. Overall, 125 patients were included in the study. The project consisted of a training phase, then an implementation phase, and the final results were measured one year after the end of the implementation phase. The imaging protocol consisted of the performance of lung ultrasounds in all the patients on CPAP (continuous positive airway pressure) or mechanical ventilation (first ultrasound at about 90 min after delivery) and the performance of chest radiographs after endotracheal intubation in any case of deterioration of the status of the patient or if such a decision was taken by the clinician. The baseline characteristics of the population were noted and compared between years 2021, 2022, and 2023. The primary outcome measures were represented by the number of X-rays performed in ventilated patients per year (including the patients on CPAP, SIMV (synchronized intermittent mandatory ventilation), IPPV (intermittent positive pressure ventilation), HFOV (high-frequency oscillatory ventilation), the number of X-rays performed per patient on CPAP/year, the number of chest X-rays performed per mechanically ventilated patient/year and the mean radiation dose/patient/year. There was no randomization of the patients for the intervention. The results were compared between the year before the project was introduced and the 2 years across which the project was implemented. Results: The frequency of cases in which no chest X-ray was performed was significantly higher in 2023 compared to 2022 (58.1% vs. 35.8%; p = 0.03) or 2021 (58.1% vs. 34.5%; p = 0.05) (a decrease of 22.3% in 2023 compared with 2022 and of 23.6% in 2023 compared with 2021). The frequency of cases with one chest X-ray was significantly lower in 2023 compared to 2022 (16.3% vs. 35.8%; p = 0.032) or 2021 (16.3% vs. 44.8%; p = 0.008). The mean radiation dose decreased from 5.89 Gy × cm2 in 2021 to 3.76 Gy × cm2 in 2023 (36% reduction). However, there was an increase in the number of ventilated patients with more than one X-ray (11 in 2023 versus 6 in 2021). We also noted a slight annual increase in the mean number of X-rays per patient receiving CPAP followed by mechanical ventilation (from 1.80 in 2021 to 2.33 in 2022 and then 2.50 in 2023), and there was a similar trend in the patients that received only mechanical ventilation without a statistically significant difference in these cases. Conclusions: The quality management project accomplished its goal by obtaining a statistically significant increase in the number of ventilated patients in which chest radiographs were not performed and also resulted in a more than 30% decrease in the radiation dose per ventilated patient. This task was accomplished mainly by increasing the number of patients on CPAP and the use only of lung ultrasound in the patients on CPAP and simple cases.

3D-navigation for SI screw fixation - How does it affect radiation exposure for patients and medical personnel?

BACKGROUND

3D-navigation for percutaneous sacroiliac (SI) screw fixation is becoming increasingly common and several studies report great advantages of this technology. However, there is still limited clinical evidence on the efficacy regarding radiation exposure for patient and personnel.

METHODS

This is a retrospective, single-center cohort study. All patients who underwent percutaneous sacroiliac screw fixation for an injury of the posterior pelvic ring from 2014 to 2021 were screened. Inclusion criteria were: conclusive radiation dosage reports, signed informed consent, a twelve month follow up and a complete data set. Patients were stratified in two groups (3D-navigation (Group 3D-N) vs. control (Group F)) based on the imaging modality used. Primary outcomes were radiation exposure for patient and personnel. Secondary outcomes were reoperations, complications, and intraoperative precision.

RESULTS

Of 392 patients screened, 174 patients (3D-N: n = 50, F: n = 124) could be included for final analysis. We noted a significant reduction of the dose corresponding to potential radiation exposure for medical personnel (-15.3 mGy, 95 %CI: -2.1 to -28.5, p = 0.0232), but also a significant increase of the dose quantifying radiation exposure for patients (+77.0 mGy, 95 %CI: +53.3 to +100.6, p < 0.0001), when using navigation. In addition, the rate of radiographic malplacement was significantly reduced (F: 11.3% vs. 3D-N: 0 %, p = 0.0113) despite a substantial increase in transsacral screw placement (F: 19.4% vs. 3D-N: 76 %).

CONCLUSION

Our data clearly suggests that the use of 3D-navigation for percutaneous SI screw fixation decreases radiation exposure for medical personnel, while increasing radiation exposure for patients. Furthermore, intraoperative precision is improved, even in more challenging operations.

Fusion Imaging Guidance Does Not Affect Radiation Exposure During Endovascular Procedures for Lower Extremity Arterial Disease: A Randomized Controlled Trial

PURPOSE

Radiation exposure for vascular interventionalists is still a concern. The aim of this study was to assess the value of advanced imaging guidance on radiation exposure and iodinated contrast volume during endovascular treatment of lower extremity arterial disease (LEAD).

MATERIALS AND METHODS

It was a prospective, randomized, monocentric, pilot, single-operator study, conducted from June 2018 to October 2019. Consecutive patients requiring a preoperative computed tomography angiography (CTA) for a symptomatic LEAD and scheduled for an iliac and/or femoropopliteal endovascular repair in a hybrid room were included. Patients were randomly assigned to the use of fusion imaging guidance (Vessel Navigator®, Philips) or not. The primary endpoint was the dose area product (DAP, Gy.cm²). Secondary endpoints were DAP for fluoroscopy, DAP for fluorography, Air Kerma, fluoroscopy time, volume of contrast, and number of digital subtraction angiography (DSA). Data were expressed in median [Q1-Q3].

RESULTS

In all, 64 of the 77 patients enrolled (34 in fusion group, 30 in control group, 82% men, 65.8 years [61-71]) were included. Groups were similar in terms of comorbidities, BMI (26 kg/cm2 [24-28]), but lesion location were not equally distributed (p=0.004). There was no significant difference between the groups regarding DAP (31.6 Gy.cm2 [23.4; 46.9] for fusion group vs 25.6[16.9; 34.0] Gy.cm2; p=0.07), Air Kerma (160 mGy [96;3365] vs 115 mGy [76;201]; p=0.12, fluoroscopy time (560 seconds [326;960] vs 454 seconds [228;1022]; p=0.44), contrast volume (60 ml [42;80] vs 50 ml [40;66]; p=0.10), or operative time (68 minutes [55;90] vs 46 minutes [30;80]; p=0.06). The median number of DSA was 14 [10-18] in the fusion group versus 11 [6-18]; p=0.049.

CONCLUSION

Fusion imaging guidance does not affect radiation exposure and contrast volume during endovascular revascularisation of iliac and femoropopliteal occlusive disease in a hybrid room environment.

Neurointerventions on two generations of angiography systems: Recent systems reduce radiation exposure by half

PURPOSE

Fluoroscopically-guided neurointervention may be associated with prolonged procedure time and substantial radiation exposure to the patient and staff. This study sought to examine technological features affecting the potential radiation exposure reduction of new angiography systems, compared to older systems, for neurointerventional procedures.

METHODS

Consecutive neurointerventional patients (2020-2022) were retrospectively analyzed. The air kerma at the reference point (Ka,r) and kerma-area product (KAP) were compared between Artis icono and Artis zee (Siemens) using statistical analyses (two-tailed t tests), where P < 0.05 is considered significant. X-ray tube potential and copper filtration were examined. Tests with an anthropomorphic phantom (Sun Nuclear) on Artis icono were conducted and entrance skin exposure and x-ray spectral half value layer were measured. Effective spectral filtration was characterized by x-ray spectral modeling.

RESULTS

The number of procedures was 1158 [median (range) age, 59 (7-95) years] on Artis zee and 1087 [60 (1-95) years] on Artis icono, without significant difference in age (p = 0.059) between cohorts. Ka,r was 925.4 (890.6-960.1) mGy [mean (95 % CI)] and KAP was 119.8 (115-124.5) Gy∙cm2 on Artis zee. The measures were 48-50 % lower on Artis icono, 440.5 (411.7-469.4) mGy (Ka,r) and 59.5 (55.4-63.6) Gy∙cm2 (KAP); while the difference in fluoroscopic time between the two generations of angiography systems was insignificant (p = 0.55).

CONCLUSIONS

The newer angiography system, with updated hardware and software, was found to result in half the radiation exposure compared to older technology of the same manufacturer, even though fluoroscopic time was similar.

National UK Survey of Radiation Doses During Endovascular Aortic Interventions

PURPOSE

Endovascular aortic repair (EAR) interventions, endovascular abdominal aortic repair (EVAR) and thoracic endovascular aortic repair (TEVAR), are associated with significant radiation exposures. We aimed to investigate the radiation doses from real-world practice and propose diagnostic reference level (DRL) for the UK.

MATERIALS AND METHODS

Radiation data and essential demographics were retrospectively collected from 24 vascular and interventional radiology centres in the UK for all patients undergoing EAR-standard EVAR or complex, branched/fenestrated (BEVAR/FEVAR), and TEVAR-between 2018 and 2021. The data set was further categorised according to X-ray unit type, either fixed or mobile. The proposed national DRL is the 75th percentile of the collective medians for procedure KAP (kerma area product), cumulative air kerma (CAK), fluoroscopy KAP and CAK.

RESULTS

Data from 3712 endovascular aortic procedures were collected, including 2062 cases were standard EVAR, 906 cases of BEVAR/FEVAR and 509 cases of TEVAR. The majority of endovascular procedures (3477/3712) were performed on fixed X-ray units. The proposed DRL for KAP was 162 Gy cm2, 175 Gy cm2 and 266 Gy cm2 for standard EVAR, TEVAR and BEVAR/FEVAR, respectively.

CONCLUSION

The development of DRLs is pertinent to EAR procedures as the first step to optimise the radiation risks to patients and staff while maintaining the highest patient care and paving the way for steps to reduce radiation exposures.

Deep learning-based scan range optimization can reduce radiation exposure in coronary CT angiography

OBJECTIVES

Cardiac computed tomography (CT) is essential in diagnosing coronary heart disease. However, a disadvantage is the associated radiation exposure to the patient which depends in part on the scan range. This study aimed to develop a deep neural network to optimize the delimitation of scan ranges in CT localizers to reduce the radiation dose.

METHODS

On a retrospective training cohort of 1507 CT localizers randomly selected from calcium scoring and angiography scans and acquired between 2010 and 2017, optimized scan ranges were delimited by two radiologists in consensus. A neural network was trained to reproduce the scan ranges and was tested on two randomly selected and independent validation cohorts: an internal cohort of 233 CT localizers (January 2018-June 2020) and an external cohort from a nearby hospital of 298 CT localizers (July 2020-December 2020). Localizers where a bypass surgery was visible were excluded. The effective radiation dose to the patient was simulated using a Monte Carlo simulation. Scan ranges of radiographers, radiologists, and the network were compared using an equivalence test; likewise, the reduction in effective dose was tested using a superior test.

RESULTS

The network replicated the radiologists' scan ranges with a Dice score of 96.5 ± 0.02 (p < 0.001, indicating equivalence). The generated scan ranges resulted in an effective dose reduction of 10.0% (p = 0.002) in the internal cohort and 12.6% (p < 0.001) in the external cohort compared to the scan ranges delimited by radiographers in clinical routine.

CONCLUSIONS

Automatic delimitation of the scan range can result in a radiation dose reduction to the patient.

CLINICAL RELEVANCE STATEMENT

Fully automated delimitation of the scan range using a deep neural network enables a significant reduction in radiation exposure during CT coronary angiography compared to manual examination planning. It can also reduce the workload of the radiographers.

KEY POINTS

• Scan range delimitation for coronary computed tomography angiography could be performed with high accuracy by a deep neural network. • Automated scan ranges showed a high agreement of 96.5% with the scan ranges of radiologists. • Using a Monte Carlo simulation, automated scan ranges reduced the effective dose to the patient by up to 12.6% (0.9 mSv) compared to the scan ranges of radiographers in clinical routine.

Quality assurance of lead aprons for radiation protection

Radiation protection is essential to minimize the harmful effects of ionizing radiation. Lead equivalent apron is one of the common protective devices to reduce the occupational risk of radiation exposure. The aim of the study is to analyse the percentage attenuation of 0.5 mm lead equivalent apron. Twenty aprons were used for calculating the percentage of attenuation. The computed tomography (CT) phantom was placed on the radiography and CT table at 1 m from the X-ray tube. The readings were taken from the phantom using a detector at 1-m distance with and without lead equivalent aprons. The readings were tabulated and analysed. The mean percentage attenuation of 0.5 mm lead equivalent apron is 95.66 ± 0.61 in radiography (100 kVp), 95.64 ± 0.57 in CT (130 kVp), respectively. The percentage attenuation of lead equivalent aprons is permissible comparing with the literature.

Radiation shielding effects of lead equivalent thickness of a radiation protective apron and distance during C-arm fluoroscopy-guided pain interventions: A randomized trial

BACKGROUND

The present study aimed to evaluate the degree of radiation shielding effects according to lead equivalent thickness and distance during C-arm fluoroscopy-guided lumbar interventions.

METHODS

The exposure time and air kerma were recorded using a fluoroscope. The effective dose (ED) was measured with and without the shielding material of the lead apron using 2 dosimeters at 2 positions. According to the lead equivalent thickness of the shielding material and distance from the side of the table, the groups were divided into 4 groups: group 1 (lead equivalent thickness 0.6 mm, distance 0 cm), group 2 (lead equivalent thickness 0.6 mm, distance 5 cm), group 3 (lead equivalent thickness 0.3 mm, distance 0 cm), and group 4 (lead equivalent thickness 0.3 mm, distance 5 cm). Mean differences such as air kerma, exposure time, ED, and ratio of EDs (ED with protector/ED without protector) were analyzed.

RESULTS

A total of 400 cases (100 cases in each group) were collected. The ratio of ED was significantly lower in groups 1 and 2 (9.18 ± 2.78% and 9.56 ± 3.29%, respectively) when compared to that of groups 3 and 4 (21.93 ± 4.19% and 21.53 ± 4.30%, respectively). The reductive effect of a 5-cm distance was 33.3% to 36.1% when comparing the ED between groups 1 and 2 and groups 3 and 4.

CONCLUSIONS

The 0.3- and 0.6-mm lead equivalent thickness protectors have a radiation attenuation effect of 78.1% to 78.5% and 90.4% to 90.8%, respectively. The 5-cm distance from the side of the table reduces radiation exposure by 33.3% to 36.1%.

Efficacy and User Experience of a Novel X-Ray Shield on Operator Radiation Exposure During Cardiac Catheterization: A Randomized Controlled Trial

BACKGROUND

Radiation shielding is mandatory during cardiac catheterization, but there is a need to improve efficacy and ease of use.

METHODS

The aim of the study was to assess the shielding effect and user feedback for a novel flexible multiconfiguration x-ray shield (FMX). The 0.5-mm Pb equivalent FMX can be selectively configured to accommodate for variations in patient morphology, access site, and type of procedure with maintained visualization, vascular access, and shielding. To evaluate efficacy, relative operator dose (operator dose indexed for given dose) was measured during 103 consecutive procedures randomized in a 1:1 proportion to the current routine setup or FMX+routine. User feedback was collected on function, relevance, and likelihood of adoption into clinical practice.

RESULTS

Median relative operator dose was 3.63 μSv/µGy·m2×10-3 (IQR, 2.62-6.37) with routine setup and 0.57 μSv/µGy·m2×10-3 (IQR, 0.27-1.06) with FMX+routine, which amounts to an 84.4% reduction (P<0.001). For 500 procedures/year, this corresponds to an estimated yearly dose reduction from 3.6 to 0.7 mSv. User feedback regarding size, functionality, ease of use, likely to use, critical issues, shielding, draping, procedure time, vascular access, patient discomfort, and risk was 99% positive. No critical issues were identified. There was no significant difference in patient radiation exposure.

CONCLUSIONS

The FMX reduces radiation exposure considerably. The FMX represents an effective and attractive solution for radiation protection that can easily be implemented in existing workflow. FMX has potential for general use with maintained visualization, vascular access, and shielding in routine cardiac catheterization.

[Mobile C-arm-Radiation exposure and workflow killer? : Potential of an innovative assistance system for intraoperative positioning]

Despite its versatile applicability the intraoperative use of a mobile C‑arm is often problematic and potentially associated with increased radiation exposure for both the patient and the personnel. In particular, the correct positioning for adequate imaging can become a problem as the nonsterile circulating nurse has to coordinate the various maneuvers together with the surgeon without having a good view of the surgical field. The sluggishness of the equipment and the intraoperative setting (sterile borders, additional hardware, etc.) pose further challenges. A light detection and ranging (LIDAR)-based assistance system shows promise to provide accurate and intuitive repositioning support as part of an initial series of experimental trials. For this purpose, the sensors are attached to the C‑arm base unit and enable navigation of the device in the operating room to a stored target position using a simultaneous localization and mapping (SLAM) algorithm. An improvement of the workflow as well as a reduction of radiation exposure represent the possible potential of this system. The advantages over other experimental approaches are the lack of external hardware and the ease of use without isolating the operator from the rest of the operating room environment; however, the suitability for daily use in the presence of additional interfering factors should be verified in further studies.

Prospective observational analysis of intraoperative radiation exposure with a mini C-arm intensifier in percutaneous forefoot surgery

INTRODUCTION

Percutaneous forefoot surgery has been associated with higher radiation exposure than the conventional approach. However, there is little data on forefoot surgery using a mini C-arm intensifier. We, therefore, conducted a prospective study to (1) evaluate the intraoperative radiation received by the surgeon during percutaneous forefoot surgery with a mini C-arm; (2) compare the radiation received by the surgeon with the guidelines for occupational exposure issued by the International Commission on Radiological Protection (ICRP) (20 millisieverts per year [mSv/year] for the whole body, 500mSv/year for the hands, and 20mSv/year for the lens of the eye); and (3) compare the radiation received during percutaneous forefoot surgery with that of the open approach, which has already been reported in the literature.

HYPOTHESIS

The radiation received by the surgeon during percutaneous forefoot surgery with a mini C-arm is lower than the ICRP guidelines, and the findings reported in the literature.

MATERIALS AND METHODS

This prospective single-center study was conducted from September 2020 to May 2021. A total of 639 feet (i.e., 435 patients) were included. Of these 639 feet, 336 (52%) were hallux valgus repairs, 49 (8%) were stand-alone procedures of the lateral rays, and 124 (19%) were a combination of both. The radiation dose data was retrieved from the mini C-arm daily: dose-area product (DAP) in centigray per square centimeter (cGy/cm2) and radiation exposure duration in seconds. The doses received by the surgeon were collected every month by 4 passive dosimeters (hand, eye lens, and chest [on and under the lead apron]) and 2 active dosimeters (on and under the lead apron).

RESULTS

The DAP emitted by the mini C-arm during an operating day was 0.10±0.01cGy/cm2 (range, 0.0-3.9), and the mean daily radiation duration was 34.7±19.3seconds (range, 0.7-226.8). There was a mean of 8±8 (range, 1-18) elective procedures per operating day. The daily reading on the active dosimeter worn on the lead apron was 0.002±0 microSv (range, 0-0.04), while the one worn under the apron was 0.001±0 microSv (range, 0-0.03). The equivalent doses over the 7-month study period for the hand, eye lens, and chest (over and under the apron) were 0.14mSv, 0mSv, 0.22mSv, and 0mSv, respectively.

DISCUSSION/CONCLUSION

The radiation exposure in percutaneous forefoot surgery with a mini C-arm intensifier observed in our study was lower than the ICRP recommendations and literature findings during open surgery.

LEVEL OF EVIDENCE

IV; prospective study without a control group.

Radiation exposure during distal and traditional radial coronary angiography and percutaneous coronary intervention: a meta-analysis of randomized controlled trials

OBJECTIVES

Previous studies show that the distal transradial approach (dTRA) is safe and effective for coronary angiography and percutaneous coronary intervention. However, the effect of dTRA on radiation exposure in the catheterization laboratory has not been characterized. The authors analyzed the available literature to compare the radiation exposure associated with dTRA vs the traditional radial approach (TRA).

METHODS

A systematic review and meta-analysis of the scientific literature was conducted by using relevant terms to search the PubMed, Embase, and Cochrane Library databases from their inception until October 13, 2022, to identify randomized controlled trials (RCTs) comparing dTRA with TRA. The primary outcome was radiation exposure reported as fluoroscopy time, air kerma, or kerma-dose product. The standard mean difference (SMD) and its 95% confidence interval were used to summarize continuous variables. Random effect and meta-regression also were used for analyses.

RESULTS

Among 484 studies identified, 7 were RCTs, with a total of 3427 patients (1712 dTRA, 1715 TRA). No difference was found between dTRA and TRA in radiation exposure quantified as fluoroscopy time (SMD -0.10 [-0.36, 0.15], P=.43) or air kerma (SMD -0.31 [-0.74, 0.13], P=.17). The overall estimate favored lower kerma-area product in the TRA (SMD 0.19 [0.08, 0.30], P=.0006). Meta-regression showed no correlation between fluoroscopy time and year of publication.

CONCLUSIONS

Compared with TRA, dTRA was associated with significantly greater radiation exposure per the kerma-area product during interventional cardiology procedures, with no differences in fluoroscopy time and air kerma.

[ANMCO Position paper: Ionizing radiation exposure and radioprotection in the cath-lab]

In the last decades, because of the improvements in the percutaneous treatment of coronary heart disease, valvular heart disease, congenital heart defects, and the increasing number of cardiac resynchronization therapy and cardioverter-defibrillator implantations, the interventional cardiologists' radio-exposure has importantly risen, causing concerns for ionizing radiation-associated diseases such as cancer and neurodegenerative disorders. Consequently, the radiation exposure issue importantly affects operators' safety. However, our knowledge of this field is poor and most operators are unaware to be at risk, especially because of the absence of effective preventive measures. The aim of this ANMCO position paper is to improve the awareness of operators and identify new ways of reducing operator ionizing radiation dose and minimizing the risk.

A practical method for routine eye lens dosimetry of staff in interventional radiology

Hospital staff doing fluoroscopy-guided interventions receive the highest doses and are at risk of exceeding the new occupational eye lens dose limit of 20 mSv. Since the introduction of the new limit in the International Commission on Radiological Protection recommendations different eye lens dose monitoring techniques have been tested on phantoms. This study uses real-life dose data to assess the need for routine eye lens dose monitoring. The correlation of eye lens dose and Hp (10) measured with a whole-body dosemeter above the lead apron was investigated as an alternative to dedicated eye lens dosimetry. A survey taken among the medical personnel allowed to determine the preferred method for measuring eye lens doses in daily practice.

Radiation dose to staff from medical X-ray scatter in the orthopaedic theatre

PURPOSE

Given the growing demand for intraoperative imaging, there is increased concern for radiation dose for orthopaedic surgical staff. This study sought to determine the distribution of scatter radiation from fluoroscopic imaging in the orthopaedic surgical environment, with particular emphasis on the positions of personnel and the type of orthopaedic surgery performed.

METHODS

A radiation survey detector was deployed at various angles and distances around an anthropomorphic phantom. The scatter dose rate in microsieverts per hour (µSv/h) was recorded using consistent exposure parameters for five common surgical procedures. A C-arm unit produced radiation for the hip arthroscopy, hip replacement and knee simulations, whilst a mini C-arm unit produced fluoroscopy for the foot and hand simulations.

RESULTS

Readings were tabulated, and coloured heatmaps were generated from scatter measurements for each of the five procedures. Positions corresponding to the typical location of the surgical staff (surgeon, surgical assistant, anaesthetist, instrument (scrub) nurse, circulation (scout) nurse and anaesthetic nurse) were superimposed on heatmaps. The surgeon's proximity to the radiation source meant this position experienced the greatest amount of radiation in all five surgical procedures. Mini C-arm doses were considered low in all procedures for positions, with and without lead protection.

CONCLUSION

This investigation demonstrated the distribution of scattered radiation dose experienced at different positions within the orthopaedic surgical theatre. It reinforces the importance of staff increasing their distance from the primary beam where possible, reducing exposure time and increasing shielding with lead protection.

Does radiation exposure during pediatric supracondylar humeral fracture surgery change according to the C-arm position? A comparison of two different techniques

INTRODUCTION

In the surgical treatment of supracondylar humeral fractures (SHF), the surgeon has to stand right next to the fluoroscopy device, so it is very important to know how to use it in the most appropriate way to reduce radiation exposure. The aim of this study was to investigate the effect of using C-arm in uniplanar (inverted) and biplanar (standard-horizontal) configurations on (1) the radiation exposure to the surgeon, and (2) surgical time and fluoroscopy exposure time.

MATERIAL AND METHODS

This prospective randomised study was conducted on 20 patients who underwent fluoroscopy during closed reduction and percutaneous pinning for a SHF. In the first configuration, the C-arm was inverted and the image intensifier was used as a surgical table. In the second configuration, the C-arm was used biplanar. The operations were performed by 5 surgeons, with each surgeon using each method only twice. During the operation, to find a value closed to direct radiation exposure measurement was made by attaching a dosimeter to the wrist and scatter radiation exposure was measured by attaching a dosimeter to the neck and waist of the surgeons. The operation time and fluoroscopy exposure time were determined.

RESULTS

The duration of operations performed with the biplanar C-arm position and the fluoroscopy exposure time in operations performed with the uniplanar method were found to be statistically significantly longer (p = 0.001). The measurements on the dosimeter worn on the neck of surgeons were found to be statistically significantly higher while using the uniplanar C-arm configuration (p = 0.001). There was no statistically significant difference between the dosimeter measurements on the wrists and waists of the surgeons and the C-arm configurations (p = 0.820; p = 0.185).

CONCLUSIONS

Although the use of biplanar C-arm has no effect on radiation exposure to the surgeon's wrist, the most important advantages are that the neck area is exposed to less radiation and it shortens the fluoroscopy time so the use of a biplanar C-arm can be recommended.

LEVEL OF EVIDENCE

Level II.

Radiation exposure for pedicle screw placement with three different navigation system and imaging combinations in a sawbone model

BACKGROUND

Studies have shown that pedicle screw placement using navigation can potentially reduce radiation exposure of surgical personnel compared to conventional methods. Spinal navigation is based on an interaction of a navigation software and 3D imaging. The 3D image data can be acquired using different imaging modalities such as iCT and CBCT. These imaging modalities vary regarding acquisition technique and field of view. The current literature varies greatly in study design, in form of dose registration, as well as navigation systems and imaging modalities analyzed. Therefore, the aim of this study was a standardized comparison of three navigation and imaging system combinations in an experimental setting in an artificial spine model.

METHODS

In this experimental study dorsal instrumentation of the thoracolumbar spine was performed using three imaging/navigation system combinations. The system combinations applied were the iCT/Curve, cCBCT/Pulse and oCBCT/StealthStation. Referencing scans were obtained with each imaging modality and served as basis for the respective navigation system. In each group 10 artificial spine models received bilateral dorsal instrumentation from T11-S1. 2 referencing and control scans were acquired with the CBCTs, since their field of view could only depict up to five vertebrae in one scan. The field of view of the iCT enabled the depiction of T11-S1 in one scan. After instrumentation the region of interest was scanned again for evaluation of the screw position, therefore only one referencing and one control scan were obtained. Two dose meters were installed in a spine bed ventral of L1 and S1. The dose measurements in each location and in total were analyzed for each system combination. Time demand regarding screw placement was also assessed for all system combinations.

RESULTS

The mean radiation dose in the iCT group measured 1,6 ± 1,1 mGy. In the cCBCT group the mean was 3,6 ± 0,3 mGy and in the oCBCT group 10,3 ± 5,7 mGy were measured. The analysis of variance (ANOVA) showed a significant (p < 0.0001) difference between the three groups. The multiple comparisions by the Kruskall-Wallis test showed no significant difference for the comparison of iCT and cCBCT (p1 = 0,13). Significant differences were found for the direct comparison of iCT and oCBCT (p2 < 0,0001), as well as cCBCT and oCBCT (p3 = 0,02). Statistical analysis showed that significantly (iCT vs. oCBCT p = 0,0434; cCBCT vs. oCBCT p = 0,0083) less time was needed for oCBCT based navigated pedicle screw placement compared to the other system combinations (iCT vs. cCBCT p = 0,871).

CONCLUSION

Under standardized conditions oCBCT navigation demanded twice as much radiation as the cCBCT for the same number of scans, while the radiation exposure measured for the iCT and cCBCT for one scan was comparable. Yet, time effort was significantly less for oCBCT based navigation. However, for transferability into clinical practice additional studies should follow evaluating parameters regarding feasibility and clinical outcome under standardized conditions.

Assessing lead curtains' impact on radiation protection in coronary interventions

The objective of this investigation is to assess the impact of supplementary lead curtains on the reduction of radiation dose exposure to operators during coronary interventional procedures. Seven standard positions during coronary angiography (foot, right foot, head, left foot, left lateral, left head, and right lateral) were simulated on a standard anthropomorphic phantom with radial artery access. Measurements were taken at two different heights, 125 cm and 155 cm, and dosimeters were used to measured surface incident dose rates for the first and second operators, both with and without additional lead curtains at various positions. Each position was measured 20 times, and arithmetic means were computed. At-test was utilised to compare dose rates with and without supplementary lead curtains, as well as dose rates with additional lead curtains at varying heights. The finding indicate that the dose rates of the first operator with supplementary lead curtains were not significantly lower compared to those without, except for the 125 cm head and left foot positions and the 155 cm head position with the additional lead curtain edge 10 cm below the umbilical level (tumbilical= 0.9, 0.4, 0.5,P> 0.05). The dose rates of the second operator with additional lead curtains were significantly lower than those without, with statistically significant differences (P< 0.05). The arithmetic mean dose rates for the first and second operators at each position were lowest when the upper edge of the additional lead curtain was situated 10 cm above the umbilical level. Employing supplementary lead curtains during coronary interventions effectively reduces radiation doses received by operators. The protective effect is enhanced when the additional lead curtain is closer to the irradiation field. Hence, it is recommended that additional curtains be employed judiciously, while ensuring that clinical procedures are not impeded, in order to effectively mitigate the radiation exposure of operators.

Trial of a Novel Radiation Shielding Device to Protect Staff in the Cardiac Catheter Laboratory

Continuous exposure to low-level scattered radiation to staff performing cardiac angiography and intervention is of concern. A novel shielding solution (NSS) (Rampart IC M1128) has the potential to provide greater shielding for staff present at the table-side. This study aimed to investigate the effectiveness of the NSS compared with a traditional shielding solution (TSS) in a randomized controlled trial that enrolled 100 patients who underwent cardiac angiography and/or intervention which were randomized to the NSS or TSS. Baseline patient characteristics and radiation dose data were collected. Staff who were scrubbed at the table-side wore 5 real-time dosimeters on the head, collar, waist, ankle, and under the apron. The median primary operator radiation dose was significantly lower (p <0.001) for all dosimeter locations with the NSS when compared with the TSS, being reduced by 86%, 80.0%, 100%, and 50.0% for the head, collar, waist, and leg respectively. Median under-apron dose was 0.0 µSv for both NSS and TSS. Median second operator dose was reduced by 100%, 100%, and 100% for the head, collar, and waist respectively (p <0.001). Median NSS and TSS dose at the ankle and under apron was 0.0 µSv. Median scrub nurse dose was reduced by 50% and 100% for the head and collar respectively (p <0.001). Median NSS and TSS dose at the waist, ankle, and under apron was 0.0 µSv. In conclusion, the NSS tested in this study demonstrates a significant decrease in radiation dose to operators and scrub nurses when compared with traditional radiation protection measures.

MLNAN: Multi-level noise-aware network for low-dose CT imaging implemented with constrained cycle Wasserstein generative adversarial networks

Low-dose CT techniques attempt to minimize the radiation exposure of patients by estimating the high-resolution normal-dose CT images to reduce the risk of radiation-induced cancer. In recent years, many deep learning methods have been proposed to solve this problem by building a mapping function between low-dose CT images and their high-dose counterparts. However, most of these methods ignore the effect of different radiation doses on the final CT images, which results in large differences in the intensity of the noise observable in CT images. What'more, the noise intensity of low-dose CT images exists significantly differences under different medical devices manufacturers. In this paper, we propose a multi-level noise-aware network (MLNAN) implemented with constrained cycle Wasserstein generative adversarial networks to recovery the low-dose CT images under uncertain noise levels. Particularly, the noise-level classification is predicted and reused as a prior pattern in generator networks. Moreover, the discriminator network introduces noise-level determination. Under two dose-reduction strategies, experiments to evaluate the performance of proposed method are conducted on two datasets, including the simulated clinical AAPM challenge datasets and commercial CT datasets from United Imaging Healthcare (UIH). The experimental results illustrate the effectiveness of our proposed method in terms of noise suppression and structural detail preservation compared with several other deep-learning based methods. Ablation studies validate the effectiveness of the individual components regarding the afforded performance improvement. Further research for practical clinical applications and other medical modalities is required in future works.

Occupational radiation exposure of electrophysiology staff with reproductive potential and during pregnancy: an EHRA survey

AIMS

Electrophysiology (EP) is a growing field in cardiology, with an increasing involvement of young people. Nevertheless, concerns about radiation exposure and its impact on reproduction and pregnancy may discourage the choice of an EP career. The study is aimed at investigating the level of awareness and main sources of concern about the effects of radiation on reproductive potential and pregnancy, exploring the safety measures adopted in different EP labs, and verifying the adherence to the current guidelines.

METHODS AND RESULTS

An online survey was conducted using the European Heart Rhythm Association (EHRA) infrastructure from April to June 2022. A total of 252 EP personnel (42% women) participated, from 50 countries and different professional roles. Most participants expressed concerns regarding the effects of radiation on reproductive capacity (67.1%) and offspring diseases (68.2%). Only 37.9% of participants were aware of the EHRA 2017 consensus document about occupational radiation exposure. Most participants (80.9%) considered that occupational radiation during pregnancy is not safe. EP female staff were not allowed to work in the EP lab during pregnancy in 48.1% of cases. Zero-fluoroscopy was the preferred choice to continue working in the EP lab during pregnancy.

CONCLUSION

EP staff, including both men and women, have concerns about the effects of radiation on reproductive capacity. Despite the recommendations issued by international bodies, implementation of the policies regarding pregnancy and occupational radiation exposure is heterogeneous. Zero-fluoroscopy is the preferred approach to ensure safety during pregnancy in the EP lab.

The Playground Shade Index: A New Design Metric for Measuring Shade and Seasonal Ultraviolet Protection Characteristics of Parks and Playgrounds

Current shading strategies used to protect outdoor playgrounds from harmful solar radiation include the placement of artificial cloth weaves or permanent roofing over a playground site, planting trees in proximity to playground equipment, and using vegetation or surface texture variations to cool playground surfaces. How and where an artificial shade structure is placed or a tree is planted to maximize the shade protection over specific playground areas, requires careful assessment of local seasonal sun exposure patterns. The Playground Shade Index (PSI) is introduced here as a design metric to enable shade and solar ultraviolet exposure patterns to be derived in an outdoor space using conventional aerial views of suburban park maps. The implementation of the PSI is demonstrated by incorporating a machine learning design tool to classify the position of trees from an aerial image, thus enabling the mapping of seasonal shade and ultraviolet exposure patterns within an existing 7180 m2 parkland. This is achieved by modeling the relative position of the sun with respect to nearby buildings, shade structures, and the identified evergreen and deciduous tree species surrounding an outdoor playground.

Radioprotection for the imaging specialist during structural heart interventions: Not an option!

Structural heart interventions are steadily increasing, and the majority requires echocardiographic guidance. As a result, imaging specialists are exposed to the harmful effects of scattered ionizing radiation. This X-ray exposure must be quantified, its potential consequences should be monitored by occupational medicine and the "as low as reasonably achievable" principles of radioprotection should be optimized (including increasing the distance, decreasing the duration, using shielding radiation and providing safety training for the imaging specialist). The spatial organization of and shielding provision in the procedural rooms should be designed to optimize radioprotection for all team members.

A Pediatric Cervical Spine Clearance Guideline Leads to Fewer Unnecessary Computed Tomography Scans and Decreased Radiation Exposure

OBJECTIVES

Physical examination and computed tomography (CT) are useful to rule out cervical spine injury (CSI). Computed tomography scans increase lifetime cancer risk in children from radiation exposure. Most CSI in children occur between the occiput and C4. We developed a cervical spine (C-spine) clearance guideline to reduce unnecessary CTs and radiation exposure in pediatric trauma patients.

METHODS

A pediatric C-spine clearance guideline was implemented in September 2018 at our Level 2 Pediatric Trauma Center. Guidance included CT of C1 to C4 to scan only high-yield regions versus the entire C-spine and decrease radiation dose. A retrospective cohort study was conducted comparing preguideline and postguideline of all pediatric trauma patients younger than 8 years screened for CSI from July 2017 to December 2020. Primary endpoints included the following: number of full C-spine and C1 to C4 CT scans and radiation dose. Secondary endpoints were CSI rate and missed CSI. Results were compared using χ 2 and Wilcoxon rank-sum test with P < 0.05 significant.

RESULTS

The review identified 726 patients: 273 preguideline and 453 postguideline. A similar rate of total C-spine CTs were done in both groups (23.1% vs 23.4%, P = 0.92). Full C-spine CTs were more common preguideline (22.7% vs 11.9%, P < 0.001), whereas C1 to C4 CT scans were more common post-guideline (11.5% vs 0.4%, P < 0.001). Magnetic resonance imaging utilization and CSIs identified were similar in both groups. The average radiation dose was lower postguideline (114 vs 265 mGy·cm -1 ; P < 0.001). There were no missed CSI.

CONCLUSIONS

A pediatric C-spine clearance guideline led to increasing CT of C1 to C4 over full C-spine imaging, reducing the radiation dose in children.

LEVEL OF EVIDENCE

Level IV, therapeutic.

Intraoperative Fluoroscopy Radiation Using OEC 9900 Elite C-arm: Risk and Method for Decreasing Exposure

ABSTRACT

The use of intraoperative fluoroscopy in surgery produces scattered radiation that can expose all operating room personnel to measurable and, in some cases, substantial radiation doses. The goal of this work is to assess and document potential radiation doses to various staff positions in a simulated standard operating room environment. Adult-sized mannequins wearing standard lead protective aprons were placed at seven positions around large and small BMI cadavers. Doses were recorded in real time at thyroid level with Bluetooth-enabled dosimeters for a variety of fluoroscope settings and imaging views. A total of 320 images were acquired, resulting in 2,240 dosimeter readings from the seven mannequins. Doses were compared to cumulative air kerma (CAK) calculations provided by the fluoroscope. There was a strong correlation between the CAK and the recorded scattered radiation doses ( P < 0.001). Radiation doses could be reduced by manipulating C-arm manual technique settings [e.g., turning off the automatic exposure control (AEC) and using pulse (PULSE) or low dose (LD) settings]. Staff position and patient size also affected the recorded doses. The highest radiation doses were recorded across all settings for the mannequin positioned immediately adjacent to the C-arm x-ray tube. The larger BMI cadaver generated greater scattered radiation than the smaller BMI cadaver for all views and settings. This work provides suggestions for reducing exposure to operating room personnel beyond standard techniques of reducing beam-on time, increasing the distance from the radiation source, and use of shielding. Simple changes in C-arm settings (turning AEC off, avoiding DS setting, use of PULSE or LD settings) can markedly reduce dose to staff.

Novel Machine Vision Image Guidance System Significantly Reduces Procedural Time and Radiation Exposure Compared With 2-dimensional Fluoroscopy-based Guidance in Pediatric Deformity Surgery

BACKGROUND

Intraoperative 2-dimensional (2D) fluoroscopy imaging has been commonly adopted for guidance during complex pediatric spinal deformity correction. Despite the benefits, fluoroscopy imaging emits harmful ionizing radiation, which has been well-established to have deleterious effects on the surgeon and operating room staff. This study investigated the difference in intraoperative fluoroscopy time and radiation exposure during pediatric spine surgery between 2D fluoroscopy-based navigation and a novel machine vision navigation system [machine vision image guidance system (MvIGS)].

METHODS

This retrospective chart review was conducted at a pediatric hospital with patients who underwent posterior spinal fusion for spinal deformity correction from 2018 to 2021. Patient allocation to the navigation modality was determined by the date of their surgery and the date of implementation of the MvIGS. Both modalities were the standard of care. Intraoperative radiation exposure was collected from the fluoroscopy system reports.

RESULTS

A total of 1442 pedicle screws were placed in 77 children: 714 using MvIGS and 728 using 2D fluoroscopy. There were no significant differences in the male-to-female ratio, age range, body mass index, distribution of spinal pathologies, number of levels operated on, types of levels operated on, and the number of pedicle screws implanted. Total intraoperative fluoroscopy time was significantly reduced in cases utilizing MvIGS (18.6 ± 6.3 s) compared with 2D fluoroscopy (58.5 ± 19.0 s) ( P < 0.001). This represents a relative reduction of 68%. Intraoperative radiation dose area product and cumulative air kerma were reduced by 66% (0.69 ± 0.62 vs 2.0 ± 2.1 Gycm 2 , P < 0.001) and 66% (3.4 ± 3.2 vs 9.9 ± 10.5 mGy, P < 0.001) respectively. The length of stay displayed a decreasing trend with MVIGS, and the operative time was significantly reduced in MvIGS compared with 2D fluoroscopy for an average of 63.6 minutes (294.5 ± 15.5 vs 358.1 ± 60.6 min, P < 0.001).

CONCLUSION

In pediatric spinal deformity correction surgery, MvIGS was able to significantly reduce intraoperative fluoroscopy time, intraoperative radiation exposure, and total surgical time, compared with traditional fluoroscopy methods. MvIGS reduced the operative time by 63.6 minutes and reduced intraoperative radiation exposure by 66%, which may play an important role in reducing the risks to the surgeon and operating room staff associated with radiation in spinal surgery procedures.

LEVEL OF EVIDENCE

Level III; retrospective comparative study.

[Radiation exposure of the spine surgeon]

INTRODUCTION

in general, spine surgeons seek to minimize soft tissue damage by using less invasive approaches, which causes them to use intraoperative images much more frequently than other surgical specialties; therefore, they are at increased risk of radiation exposure.

OBJECTIVE

the aim of this work was to analyse the amount of radiation to which the spine surgeon is exposed in different scenarios.

MATERIAL AND METHODS

a prospective study with a descriptive, longitudinal non-randomized data source. We carried out this study in the period from 2015 to 2019, the radiologic protection consisted in lead apron, thyroid shield and leaded glasses, there were 10 badge dosimeters.

RESULTS

only 4 dosimeters were included in the study, the other six were excluded. During the study period one surgeon suffered thyroid cancer and other suffered of liposarcoma. In the protected group were two surgeons, in the group of aleatory exposition was one surgeon and in the unprotected group was one surgeon. In the study the dosimeter in the unprotected group received more amount of radiation in all the years, we did an inferential analysis per year related with the number of surgeries without significant correlation, we attribute this result because we didn't classified the type of surgery realized by each surgeon.

CONCLUSION

we conclude that the spine surgeon must apply the primary methods of radiological protection and that the unprotected spine surgeon receives more amount of radiation in comparison of the protected ones.

Protective Attitudes toward Occupational Radiation Exposure among Spine Surgeons in Japan: An Epidemiological Description from the Survey by the Society for Minimally Invasive Spinal Treatment

Background and Objectives: The global trend toward increased protection of medical personnel from occupational radiation exposure requires efforts to promote protection from radiation on a societal scale. To develop effective educational programs to promote radiation protection, we clarify the actual status and stage of behavioral changes of spine surgeons regarding radiation protection. Materials and Methods: We used a web-based questionnaire to collect information on the actual status of radiation protection and stages of behavioral change according to the transtheoretical model. The survey was administered to all members of the Society for Minimally Invasive Spinal Treatment from 5 October to 5 November 2020. Results: Of 324 members of the Society for Minimally Invasive Spinal Treatment, 229 (70.7%) responded. A total of 217 participants were analyzed, excluding 12 respondents who were not exposed to radiation in daily practice. A trunk lead protector was used by 215 (99%) participants, while 113 (53%) preferred an apron-type protector. Dosimeters, thyroid protector, lead glasses, and lead gloves were used by 108 (50%), 116 (53%), 82 (38%), and 64 (29%) participants, respectively. While 202 (93%) participants avoided continuous irradiation, only 120 (55%) were aware of the source of the radiation when determining their position in the room. Regarding the behavioral change stage of radiation protection, 134 (62%) participants were in the action stage, while 37 (17%) had not even reached the contemplation stage. Conclusions: We found that even among the members of the Society for Minimally Invasive Spinal Treatment, protection of all vulnerable body parts was not fully implemented. Thus, development of educational programs that cover the familiar risks of occupational radiation exposure, basic protection methods in the operating room, and the effects of such protection methods on reducing radiation exposure in actual clinical practice is warranted.

The impact of steerable sheath visualization during catheter ablation for atrial fibrillation

AIMS

Incorporating a steerable sheath that can be visualized using an electroanatomical mapping (EAM) system may allow for more efficient mapping and catheter placement, while reducing radiation exposure, during ablation procedures for atrial fibrillation (AF). This study evaluated fluoroscopy usage and procedure times when a visualizable steerable sheath was used compared with a non-visualizable steerable sheath for catheter ablation for AF.

METHODS AND RESULTS

In this retrospective, observational, single-centre study, patients underwent catheter ablation for AF using a steerable sheath that is visualizable using the CARTO EAM (VIZIGO; n = 57) or a non-visualizable steerable sheath (n = 34). The acute procedural success rate was 100%, with no acute complications in either group. Use of the visualizable sheath vs. the non-visualizable sheath was associated with a significantly shorter fluoroscopy time [median (first quartile, third quartile), 3.4 (2.1, 5.4) vs. 5.8 (3.8, 8.6) min; P = 0.003], significantly lower fluoroscopy dose [10.0 (5.0, 20.0) vs. 18.5 (12.3, 34.0) mGy; P = 0.015], and significantly lower dose area product [93.0 (48.0, 197.9) vs. 182.2 (124.5, 355.0) μGy·m2; P = 0.017] but with a significantly longer mapping time [12.0 (9.0, 15.0) vs. 9.0 (7.0, 11.0) min; P = 0.004]. There was no significant difference between the visualizable and non-visualizable sheaths in skin-to-skin time [72.0 (60.0, 82.0) vs. 72.0 (55.5, 80.8) min; P = 0.623].

CONCLUSION

In this retrospective study, use of a visualizable steerable sheath for catheter ablation of AF significantly reduced radiation exposure vs. a non-visualizable steerable sheath. Although mapping time was longer with the visualizable sheath, the overall procedure time was not increased.

Adding interactive face-to-face lectures to passive lectures effectively reduces radiation exposure during atrial fibrillation ablation

BACKGROUND

Radiation exposure remains a major concern for electrophysiologists and patients. This study aimed to investigate the effect of altering awareness of radiation exposure during atrial fibrillation ablation using interactive face-to-face (FTF) lectures compared to passive lectures.

METHODS

Patients who underwent their first catheter ablation with radiofrequency energy for atrial fibrillation between January 2014 and December 2020 were included in this study. All operators attended an e-learning lecture on radiation exposure before catheter ablation. The addition of FTF lectures to this lecture was introduced in 2018. The effect on radiation exposure was compared between the pre-FTF and FTF periods by comparing fluoroscopy time and radiation dose.

RESULTS

A total of 896 patients [mean age, 66 ± 11 years; 603 men (67 %)] were included in this study. For pre-FTF (n = 345), only pulmonary vein isolation (PVI) was performed in 112 patients and PVI with additional ablation in 233 patients. For FTF lectures (n = 551), PVI-only was performed in 302 patients and PVI with additional ablation in 249 patients. Fluoroscopy time, cumulative air kerma, and cumulative air kerma per time significantly reduced after FTF introduction in both PVI-only group [pre-FTF and FTF; 37 ± 15 min and 16 ± 10 min (p < 0.0001), 477 ± 582 mGy and 108 ± 156 mGy (p < 0.0001), 11 ± 12 mGy/min, and 5 ± 6 mGy/min (p < 0.0001), respectively] and PVI with additional ablation group [pre-FTF and FTF; 48 ± 17 min and 15 ± 13 min (p < 0.0001), 613 ± 483 mGy and 68 ± 96 mGy (p < 0.0001), 12 ± 10 mGy/min, and 4 ± 4 mGy/min (p < 0.0001), respectively]. There were no significant differences in intraoperative complications between the two periods.

CONCLUSIONS

FTF lectures can reduce radiation exposure.

Tips and pitfalls to improve accuracy and reduce radiation exposure in intraoperative CT navigation for pediatric scoliosis: a systematic review

BACKGROUND CONTEXT

An increasing number of medical centers are adopting an intraoperative computed tomography (iCT) navigation system (iCT-Navi) to provide three-dimensional navigation for pediatric scoliosis surgery. While iCT-Navi has been reported to provide higher pedicle screw (PS) insertion accuracy, it may also result in higher radiation exposure to the patient. What innovations and studies have been introduced to reduce radiation exposure and further improve PS insertion?

PURPOSE

Evaluate the level of evidence and quality of papers while categorizing the tips and pitfalls regarding pediatric scoliosis surgery using iCT-Navi. Compare iCT-Navi with other methods, including preoperative CT navigation.

STUDY DESIGN

Systematic review.

PATIENT SAMPLE

Articles on pediatric scoliosis surgery with iCT-Navi published through to June 2022.

OUTCOME MEASURES

PS perforation rate and patient intraoperative radiation dose.

METHODS

Following PRISMA guidelines, the Cochrane Library, Google Scholar, and PubMed databases were searched for articles satisfying the criteria of iCT-Navi use and pediatric scoliosis surgery. The level of evidence and quality of the articles meeting the criteria were evaluated according to the guidelines of the North American Spine Society and American Academy of Orthopedic Surgeons, respectively. The articles were also categorized by theme and summarized in terms of PS insertion accuracy and intraoperative radiation dose. The origins and characteristics of five major classification methods of PS perforation grade were summarized as well.

RESULTS

The literature search identified 811 studies, of which 20 papers were included in this review. Overall, 513 pediatric scoliosis patients (381 idiopathic, 44 neuromuscular, 39 neurofibromatosis type 1, 28 congenital, 14 syndromic, seven other) were evaluated for PS perforations among 6,209 iCT-Navi insertions. We found that 232 (3.7%) screws were judged as major perforations (G2 or G3), 55 (0.9%) screws were judged as dangerous deviations (G3), and seven (0.1%) screws were removed. There were no reports of neurovascular injury caused by PSs. The risk factors for PS perforation included more than six vertebrae distance from the reference frame, more than nine consecutive insertions, upper thoracic level, thinner pedicle, upper instrumented vertebra proximity, short stature, and female. The accuracy of PS insertion did not remarkably decrease when the radiation dose was reduced to 1/5 or 1/10 by altering the iCT-Navi protocol.

CONCLUSIONS

iCT-Navi has the potential to reduce PS perforation rates compared with other methods. The use of low-dose radiation protocols may not significantly affect PS perforation rates. Although several risk factors for PS perforation and measures to reduce radiation dose have been reported, the current evidence is limited by a lack of consistency in classifying PS perforation and evaluating patient radiation dose among studies. The standardization of several outcome definitions is recommended in this rapidly developing field.

Low-dose fluoroscopy technique drastically decreases patient radiation exposure during percutaneous nephrolithotomy

Fluoroscopy is essential in percutaneous nephrolithotomy (PCNL) but exposes patients and operating room staff to radiation. We investigated whether a low-dose (LD) protocol could reduce radiation exposure during fluoroscopy-guided access without compromising clinical outcomes. Patients undergoing PCNL with fluoroscopy-guided access at a tertiary care stone center between January 2019 and July 2021 were identified. Prior to September 3, 2020, the Philips Veradius C-arm's default settings were used: standard per-frame dose, 15 pulses per second (PPS) frame rate. After this date, a low-dose protocol was used: reduced per-frame dose, reduced frame rate of 8 PPS for needle puncture and 4 PPS for all other steps. Clinical and radiographical data were retrospectively collected. The primary outcome was cumulative radiation dose. Secondary outcomes were stone-free status (SFS; defined as no fragments ≥ 2 mm) and complications. Multivariate regression analysis was performed. 100 patients were identified; 31 were in the LD group. The LD cohort was exposed to a significantly lower mean cumulative radiation dose of 11.68 mGy compared to 48.88 mGy (p < 0.0001). There were no differences in operative time, fluoroscopy time, stone burden, SFS, or complications. In a multivariable regression model adjusting for several variables, LD protocol was associated with lower radiation dose while skin-to-calyx-distance (STCD) was positively associated with cumulative radiation dose. Low-dose fluoroscopy and decreased frame rate during PCNL decreased radiation exposure fourfold without affecting SFS or complication rates.