Comparison between radiation exposure levels using an image intensifier and a flat-panel detector-based system in image-guided central venous catheter placement in children weighing less than 10 kg

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.

Local reference and achievable dose levels for vascular and enterostomy access procedures in pediatric interventional radiology

BACKGROUND

Knowledge of radiation quantities delivered in routine practice is an essential responsibility of a pediatric interventional radiology department.

OBJECTIVE

To review radiation indices in frequently performed vascular and enterostomy access procedures at a quaternary pediatric hospital to formulate dosimetric reference levels and achievable levels.

MATERIALS AND METHODS

A retrospective review of patient demographics, procedure information and quantitative dose metrics over a 2-year period was performed. Dosimetric details for common procedures (central line insertions, gastrostomy/gastrojejunostomy insertions and maintenance) were evaluated, correlated with demographic data and stratified across five weight groups (0-5 kg, 5-15 kg, 15-30 kg, 30-50 kg, 50-80 kg). Achievable (50th percentile) and reference (75th percentile) levels with confidence intervals were established for each procedure.

RESULTS

Within the evaluation period, 3,165 studies satisfied the inclusion criteria. Five were classified as device insertions (peripherally inserted central catheter, n=1,145; port-a-catheter, n=321; central venous line, n=285; gastrostomy-tube [G-tube], n=262, and gastrojejunostomy-tube [GJ-tube], n=66), and two were classified as maintenance procedures (G-tube, n=358, and GJ-tube, n=728, checks, exchanges and reinsertions). Representative reference and achievable levels were calculated for each procedure category and weight group.

CONCLUSION

This work highlights the creation of local reference and achievable levels for common pediatric interventional procedures. These data establish a dosimetric reference to understand the quantity of radiation routinely applied, allowing for improved relative radiation risk assessment and enriched communication to interventionalists, health care providers, parents and patients.

Flat Panel Detector c-Arms Are Associated with Dramatically Reduced Radiation Exposure During Ureteroscopy and Produce Superior Images

Background: We wished to determine whether newly available flat panel detector (FPD) c-arms were (1) associated with lower radiation dose during ureteroscopy (URS) than conventional image intensifier (CII) c-arms and (2) to compare fluoroscopic image quality between the units. Materials and Methods: We retrospectively reviewed 44 consecutive patients undergoing URS at a pediatric hospital, with c-arms assigned by availability in the operating room. We performed dosimetry experiments using the same c-arms on standard phantoms. Results: Patient and case characteristics did not differ significantly between the two groups of patients. The median dose in the FPD group was less than a quarter of the dose in the CII group, 0.48 [0.42, 0.97] mGy vs 2.2 [1.1, 3.8] mGy, p < 0.0001. The FPD dose remained at less than one-third of the CII dose accounting for any difference in fluoroscopy time, and remained significant in a multivariate model including fluoroscopy time and patient weight (β = 2.4, p = 0.007). Phantom studies showed higher image quality for FPDs at all simulated patient sizes, even at lower radiation doses. Conclusions: This is the first report comparing radiation dose from c-arms of image intensifiers and FPDs in adults or children. Use of an FPD during URS was associated with a substantially decreased absorbed dose for patients while simultaneously improving image quality.

Radiation burden of pediatric ultrasound-guided percutaneous central venous access devices: A prospective cohort study

Permanent central venous access is essential for the management of many pediatric patients. Knowing the amount of ionizing radiation used during the insertion of these devices is important. Our aim was to identify the radiation used in percutaneous insertion of central venous access devices, and to correlate radiation exposure to patient weight.

METHODS

Data was prospectively collected during a 12-month period from August 2015 to August 2016 on all ultrasound-guided percutaneous central venous access device insertions. An image intensifier was used in all insertions with data on radiation dose and screening time extracted, when available. The total radiation dose was measured in mGym2 and the total radiation time in seconds. A p-value <0.05 was used to denote statistical significance.

RESULTS

A total of 145 central venous access devices were inserted (82 portacaths, 43 double lumen lines, 16 single lumen lines and 4 hemocaths) in 127 patients (Median Age: 5.5years (Range 0-17); Median Weight 21kg (Range 1.9-100)) with 15 patients requiring multiple insertions over the course of the study. Of these, 88 had data captured for total radiation dose and time used and a further 23 had screening time only recorded. Median radiation dose was 0.00599 mGym2 (range 0.000543-0.148) with a median fluoroscopic screening time of 18s (range 2-479). Median dose was higher for children <10kg compared to larger children, 0.00661 mGym2 (range 0.00202-0.0468) versus 0.005715 mGym2 (range 0.000543-0.148) respectively. Left-sided internal jugular vein (IJV) insertions also had a higher median radiation dose of 0.0091 mGym2 (range 0.00142-0.148 mGym2) versus 0.005245 mGym2 (range 0.000543-0.0285 mGym2) for right-sided IJV insertions.

CONCLUSION

The radiation burden to children from percutaneous ultrasound-guided central venous access device insertions is small, in the order of that received during a chest radiograph. Weight<10kg and access of the left IJV are associated with receiving higher doses.

STUDY TYPE

Cohort Study (Level of Evidence: II).

Comparison of image quality and radiation dose between an image-intensifier system and a newer-generation flat-panel detector system — technical phantom measurements and evaluation of clinical imaging in children

BACKGROUND

Many image-intensifier fluoroscopy systems have been replaced by flat-panel detectors in recent years.

OBJECTIVE

To compare the level of contrast, image resolution and radiation dose between an image-intensifier and a newer-generation flat-panel detector system in a pediatric radiology unit.

MATERIALS AND METHODS

We compared two systems — a conventional image intensifier and a newer-generation flat-panel system. We measured image quality and radiation dose using a technical phantom. Additionally, we retrospectively compared age-matched fluoroscopic pediatric voiding cystourethrography (n = 15) and upper gastrointestinal investigations (n = 25).

RESULTS

In phantom studies image contrast was equal while image resolution was higher and mean radiation dose lower using the flat-panel system (P < 0.0001). In pediatric investigations, mean dose area product was significantly reduced on the flat-panel system for upper gastrointestinal investigation (45 ± 38 μGy*m2 vs. 11 ± 9 μGy*m2; P < 0.0001) and for voiding cystourethrography (18 ± 20 μGy*m2 vs. 10 ± 12 μGy*m2; P = 0.04).

CONCLUSION

The newer flat-panel system performs at lower dose levels with equal to better image quality and therefore seems to be the more suitable technique for pediatric fluoroscopy in comparison to image-intensifier systems.

Radiation Exposure in Transjugular Intrahepatic Portosystemic Shunt Creation

PURPOSE

Transjugular intrahepatic portosystemic shunt (TIPS) creation is considered as being one of the most complex procedures in abdominal interventional radiology. Our aim was twofold: quantification of TIPS-related patient radiation exposure in our center and identification of factors leading to reduced radiation exposure.

MATERIALS AND METHODS

Three hundred and forty seven consecutive patients underwent TIPS in our center between 2007 and 2014. Three main procedure categories were identified: Group I (n = 88)-fluoroscopic-guided portal vein targeting, procedure done in an image intensifier-based angiographic system (IIDS); Group II (n = 48)--ultrasound-guided portal vein puncture, procedure done in an IIDS; and Group III (n = 211)--ultrasound-guided portal vein puncture, procedure done in a flat panel detector-based system (FPDS). Radiation exposure (dose-area product [DAP], in Gy cm(2) and fluoroscopy time [FT] in minutes) was retrospectively analyzed.

RESULTS

DAP was significantly higher in Group I (mean ± SD 360 ± 298; median 287; 75th percentile 389 Gy cm(2)) as compared to Group II (217 ± 130; 178; 276 Gy cm(2); p = 0.002) and Group III (129 ± 117; 70; 150 Gy cm(2) p < 0.001). The difference in DAP between Groups II and III was also significant (p < 0.001). Group I had significantly longer FT (25.78 ± 13.52 min) as compared to Group II (20.45 ± 10.87 min; p = 0.02) and Group III (19.76 ± 13.34; p < 0.001). FT was not significantly different between Groups II and III (p = 0.73).

CONCLUSIONS

Real-time ultrasound-guided targeting of the portal venous system during TIPS creation results in a significantly lower radiation exposure and reduced FT. Further reduction in radiation exposure can be achieved through the use of modern angiographic units with FPDS.