Approaches to Eliminate Radiation Exposure in the Management of Pediatric Urolithiasis

Radiation exposure associated with computed tomography for pediatric urolithiasis evaluation: A scoping review of the literature

INTRODUCTION

Computed tomography (CT) imaging is used for assessment of pediatric urolithiasis in cases where ultrasound is inconclusive. The utility of CT imaging must be considered alongside the potential risks of radiation exposure in this patient population due to the increased risk of cancer development. The purpose of this review is to investigate the radiation exposure associated with standard-dose and low-dose computed tomography (CT) imaging for the assessment of pediatric urolithiasis.

METHODS

A scoping literature review over a 23 year period between 2000 and 2023 was conducted of all English-language studies reporting on the use of non-contrast CT imaging for assessment of pediatric urolithiasis. Patients that were specified as pediatric with age ≤20 years at time of intervention and undergoing standard-dose or low/ultra-low-dose CT were included. Low-dose and ultra-low-dose CT were defined as a radiation dose ≤3.0 mSv and ≤1.9 mSv, respectively.

RESULTS

A total of 8121 articles were identified and after screening, 6 articles representing 309 patients were included in this scoping review. Of the articles reviewed, standard non-contrast CT radiation doses for pediatric urolithiasis evaluation ranged from 2.9 to 5.5 mSv and low-dose CT radiation dose was reported to be 1.0-2.72 mSv. Only 2 studies directly evaluated low-dose CT imaging compared to standard-dose CT imaging for pediatric urolithiasis assessment. Radiation reduction approaches did not negatively impact urolithiasis detection or characterization in 2 studies reviewed.

CONCLUSIONS

CT radiation doses for suspected or known pediatric urolithiasis are underreported and vary greatly with underutilization of low-dose/ultra-dose protocols for pediatric urolithiasis especially in comparison to the adult population. Results from this scoping review support that low-dose CTprotocols for pediatric stone disease are feasible to reduce radiation exposure.

Radiation exposure during different percutaneous renal puncture techniques: A YAU endourology & urolithiasis study

PURPOSE

Radiation exposure is affected by C-arm fluoroscopy device positioning during percutaneous renal puncture. Our aim was to compare the exposure of surgeon's lens, hand and chest with a fluoroscopy protocol replicated in different C-arm positions.

MATERIALS AND METHODS

A standardized fluoroscopy protocol was created using water-equivalent solid phantoms to replicate a surgeon and patient. 111 mGy radiation (360 s) was applied in standard fluoroscopy mode (91 kVp, 2.7 mA/mAs). Dosimeters were placed on lens, chest and hand of surgeon and patient phantom models. 7 different C-arm positions were created: 0°, mediolateral (ML) +90°, ML -90°, ML +30°, ML -15°, craniocaudal (CC) +30°, CC +15°. Measurements were evaluated separately for different positions.

RESULTS

The highest radiation exposure was measured on patient dosimeter (2.97 mSv). The highest exposure on surgeon was recorded on finger dosimeter in all C-arm positions; highest dose was recorded in ML +90° position (2.88 mSv). In finger dosimeters, lowest exposure was recorded in 0° position (0.51 mSv). The lowest exposure of all positions was measured in chest dosimeter in ML -90° position (0.24 mSv).

CONCLUSIONS

In positions where X-ray generator of the C-arm was facing towards the surgeon, radiation exposure measured in all dosimeters was higher compared to positions where the generator was facing away. The hand radiation exposure in all positions was higher than chest and lens. Special care must be taken to avoid facing the X-ray generator tube and hands should be as well-protected as chest and eyes with special protective gear.

Pediatric Stone Disease: Current Trends and Future Directions

Pediatric nephrolithiasis is less common in children than in adults but the incidence has been rising rapidly, and it is now a public health and economic burden in the United States. There are challenges unique to children that should be taken into consideration when evaluating and managing pediatric stone disease. In this review, we present the current research on risk factors, emerging new technologies for treatment of stones and recent investigations on prevention of stones in this population.

Value of deep learning reconstruction at ultra-low-dose CT for evaluation of urolithiasis

OBJECTIVES

To determine the diagnostic accuracy and image quality of ultra-low-dose computed tomography (ULDCT) with deep learning reconstruction (DLR) to evaluate patients with suspected urolithiasis, compared with ULDCT with hybrid iterative reconstruction (HIR) by using low-dose CT (LDCT) with HIR as the reference standard.

METHODS

Patients with suspected urolithiasis were prospectively enrolled and underwent abdominopelvic LDCT, followed by ULDCT if any urinary stone was observed. Radiation exposure, stone characteristics, image noise, signal-to-noise ratio (SNR), and subjective image quality on a 5-point Likert scale were evaluated and compared.

RESULTS

The average effective radiation dose of ULDCT was significantly lower than that of LDCT (1.28 ± 0.34 vs. 5.49 ± 1.00 mSv, p < 0.001). According to the reference standard (LDCT-HIR), 148 urinary stones were observed in 85.0% (51/60) of patients. ULDCT-DLR detected 143 stones with a rate of 96.6%, and ULDCT-HIR detected 142 stones with a rate of 95.9%. The urinary stones that were not observed with ULDCT-DLR or ULDCT-HIR were renal calculi smaller than 3 mm. There were no significant differences in the detection of clinically significant calculi (≥ 3 mm) or stone size estimation among ULDCT-DLR, ULDCT-HIR, and LDCT-HIR. The image quality of ULDCT-DLR was better than that of ULDCT-HIR and LDCT-HIR with lower image noise, higher SNR, and higher average subjective score.

CONCLUSIONS

ULDCT-DLR performed comparably to LDCT-HIR in urinary stone detection and size estimation with better image quality and decreased radiation exposure. ULDCT-DLR may have potential to be considered the first-line choice to evaluate urolithiasis in practice.

KEY POINTS

• Ultra-low-dose computed tomography (ULDCT) has been investigated for diagnosis of urolithiasis, but stone evaluation may be adversely impacted by compromised image quality. • This study evaluated the value of novel deep learning reconstruction (DLR) at ULDCT by comparing the stone evaluation and image quality of ULDCT-DLR to the reference standard of low-dose CT (LDCT) with hybrid iterative reconstruction (HIR). • ULDCT-DLR performed comparably to LDCT-HIR in urinary stone detection and size estimation with better image quality and reduced radiation exposure.

Surgical treatment of pediatric urolithiasis

Introduction: Surgical treatment of urolithiasis in children is quite complex and specific due to certain anatomical and functional features of childhood. Methods of surgical treatment at this age are: extracorporeal lithotripsy (ESWL), intracorporeal (endoscopic) lithotripsy - pneumatic and laser, percutaneous nephrolithotripsy (PCNL) and open surgery. Aim: The aim of this study was evaluation of the effects of ureterorenoscopy and endoscopic lithotripsy in children, as methods of minimally invasive surgical treatment. Material and methods: The retrospective study was conducted at the Institute for Mother and Child Health Care of Serbia "Dr Vukan Cupic" in Belgrade from 2010 to 2020. The study included 112 patients (50 boys and 62 girls) aged 1-18 years with urolithiasis, treated by endoscopic (laser or pneumatic) lithotripsy. The retrospective study was conducted at the Institute for Mother and Child Health Care of Serbia "Dr Vukan Cupic" in Belgrade from 2010 to 2020. The study included 112 patients (50 boys and 62 girls) aged 1-18 years with urolithiasis, treated by endoscopic (laser or pneumatic) lithotripsy. Results: After one ureterorenoscopy, the calculus was successfully disintegrated in 87 (78%) patients: in the renal pelvis in 22 (79%), in the upper pole calices of the kidney in 14 (100%), in the lower pole calices in 10 (50%), in the proximal segment of the ureter in 10 (83%), in the distal segment of the ureter in 27 (79%), in the bladder in 4 (100%) cases. In 19 (17%) patients the second intervention was necessary: in the renal pelvis in 28 (100%), in the upper pole calices in 14 (100%), in the lower pole calices in 14 (70%), in the proximal segment of the ureter in 12 (100%), in the distal segment of the ureter in 34 (100%) and in the bladder in 4 (100%) patients. Conclusion: The primary treatment of pediatric urolithiasis is ureterorenoscopy in combination with pneumatic or laser lithotripsy. It is successfully used in all segments of the urinary tract. The procedure is partially limited in the lower pole calices of the kidney, due to anatomical circumstances and mechanical limitations of the instruments.

Can ultrasound guidance reduce radiation exposure significantly in percutaneous nephrolithotomy in pediatric patients?

In this study, we aimed to compare clinical and technical outcomes between pediatric patients who underwent percutaneous nephrolithotomy (PCNL) under fluoroscopy (FL) and those that underwent this procedure under FL with ultrasound assistance (FLUSA). The data of 66 PCNL patients were analyzed retrospectively. Renal puncture was successful in 22 patients in the FLUSA group and 44 patients in the FL group. In all cases, FL was used for tract dilation and confirmation of ureteral catheter positioning at the beginning of the procedure. The sample consisted of 46 males and 20 females with a mean age of 7.2 ± 2.1 years (range 1-17 years). Stone size varied from 8.0 to 75.4 mm, and 89% of patients achieved a completely stone-free state. The median puncture time was 130.5 ± 25.3 s for FLUSA and 295 ± 82.8 s for FL, the median fluoroscopic screening time was 95 ± 33 and 230 ± 116 s, respectively, and the median radiation dose was 19.04 ± 9.9 dGy/cm² and 54 ± 21.4 dGy/cm², respectively. The median puncture time, fluoroscopic screening time, and radiation dose were statistically lower in the FLUSA group (p = 0.001, Mann-Whitney U test). The greatest problem in PCNL is the use of fluoroscopy. Due to some anatomical differences from adults, applying PCNL in pediatric patients using only ultrasound may decrease the success rate. Puncture with ultrasound significantly reduces the radiation dose in children. Puncture with ultrasound and dilation under fluoroscopy is a successful and safe treatment method with low morbidity and high success rates and shorter hospital stay in pediatric patients.

Retrograde intrarenal surgery without fluoroscopy: Is it possible? A randomized prospective study, an extraordinary experience

OBJECTIVES

The aim of this study was to evaluate the role of the use of fluoroscopy in patients undergoing retrograde intrarenal surgery and the effect on surgical outcomes.

MATERIAL AND METHODS

The patients who were admitted to our center with the diagnosis of kidney stones were divided into 2groups. In group 1, routine fluoroscopy was used in all cases (n: 58). In group 2, the same procedure was performed without fluoroscopy (n: 67) and the results of the 2groups were compared.

RESULTS

There were no statistically significant differences between the 2groups in terms of operation time, stone-free rate, complication rate, need for analgesic and re-treatment requirement and Visual Analogic Scale score.

CONCLUSION

The use of fluoroscopy does not alter the complication frequency and stone-free rate. We think that the use of fluoroscopy is not mandatory in cases in which renal pelvis access is achieved especially with semirigid ureteroscopy and that unnecessary fluoroscopy increases radiation exposure.