Radiation Reduction in Paediatric Cardiac Catheterization: We Can Go Even Lower.
Finke T, Mainzer G, Yitzhak Y, Devadas S, Mroczek D, Benson LN, Borik S. CJC Pediatr Congenit Heart Dis. 2024 May 31;3(4):129-136. doi: 10.1016/j.cjcpc.2024.05.004. eCollection 2024 Aug. PMID: 39493664 Free PMC article.
Commentary by Dr. Lahiri, section editor of Congenital Heart Disease Interventions Journal Watch:
The authors state that the ALARA principle – “as low as reasonably achievable” – is essential for congenital cardiac catheterization, especially in children who need repeat procedures over their lifespan. The authors then compared the levels of radiation between two large tertiary care catheterization laboratories: one in Israel and one in Canada. The measures used were dose area product (DAP), DAP per body weight, total air kerma, and fluoroscopy time. The cath lab in Israel was labeled as unit A, and the cath lab in Canada was labeled as unit B. Unit A used AlluraClarity with ClarityIQ technology, which reduces noise and enhances image projection while using lower X-ray doses. Pulsed fluoroscopy was performed at 7.5 f/s, and cineangiograms were performed at 15 f/s. The data were compared with the most recently available (June 2011 to May 2014) data for the corresponding procedure types and radiation reduction protocol from the Hospital for Sick Kids, Canada.
Radiation Safety Measures Implemented at Safra Children’s Hospital, Sheba Medical Center
- Fluoroscopy frame rate: 7.5 frames/s
- Air gap technique for all children below 30 kg
- Use of minimal magnification during procedures
- Limited field of view to the minimum necessary
- Use of “low” radiation preset with brief increases as clinically necessary
- Fluoroscopy image storage in place of digital imaging
- Weight-based reductions in preset frame rates
- Exposure to ionizing radiation as part of the consent process
- Use of Philips ClarityIQ technology
- High awareness of all team members to the “as low as reasonably achievable” principle
- Hiring of a radiation technician devoted to radiation reduction
- Regular updates to new systems
Catheterizations in unit B were performed at 7.5 frames/s for fluoroscopy and 30 frames/s for cineangiography, using similar protocols to those in unit A, with removal of the anti-scatter grid for all patients <20 kg, allowing for data comparison. Unit B procedures were performed, and images were acquired on two Siemens biplane flat-panel detector digital angiographic systems (Artis zee [lab I] and Axiom Artis [lab II]; Siemens Medical Solutions).
Center A analyzed 627 cases, and Center B had 2,033 cases. Below is the comparison of radiation between the two hospitals.
A Few Interesting Findings:
- Ionizing radiation was not much different for PDA closures between the two centers.
- Fluoroscopy times were not different except for 4 procedures (shorter in Center A).
- The highest radiation exposure was seen, as expected, in pulmonary valve procedures, and the highest fluoroscopy times were in pulmonary valve perforation in both institutions.
In summary, the authors show that there could be further reduction of radiation doses across 16 procedure types. This is achievable with newer technology, removal of anti-scatter grids for all patients <30 kg, and increasing awareness.
It must be emphasized that fluoroscopy time in pediatrics does not correlate with median radiation doses, which are often used as a benchmark in adult labs. There are timers in pediatric labs built in for fluoroscopy time, which may serve as a good reminder for physicians to step off fluoroscopy during cases. However, these should not be the sole parameters on which to base hospital policies and protocols. In our lab, we use ultra-low fluoroscopy rates of 3.5 f/s and cine-rates of 7.5 f/s, along with increasing awareness among team members, which has resulted in significant improvement in radiation exposure for both us and the patients.
Cardiac catheterization is heavily technology dependent. In this modern era of rapidly evolving technology, the safety of both operators and patients will likely improve over time, with an ever-changing goal of decreasing radiation, all while keeping in sync with the concept of ALARA.
