Techniques for Minimizing Radiation Exposure During Evaluation, Surgical Treatment, and Follow-up of Urinary Lithiasis

Adopting ultrasound guided PCNL in nephrolithiasis management

INTRODUCTION

This study aimed to evaluate the learning curve associated with the adoption of US guided PCNL and demonstrate that it can be carried out safely with results comparable to those obtained using standard PCNL.

METHODS

Prospective study with 65 patients who underwent PCNL between 2019 and 2020. all procedures were performed in supine position and an initial attempt to gain access to the kidney using US was made.

RESULTS

Mean procedure duration was 69.5 ± 27.8 min. Fluoroscopy was used with a mean dose of 276.68 ± 560.71 (cGycm3) and mean fluoroscopy time 40.25 ± 77.69 (s). Throughout the study there was a steady decrease in the use of fluoroscopy and amount of radiation to gain access to the kidney to only 25% at the study end. 76.5% of the patients were stone free at follow-up. Complication rate was 9.2%.

CONCLUSIONS

Fluoroless US guided PCNL is safe, feasible and reproducible procedure.

Reducing hand radiation during renal access for percutaneous nephrolithotomy: a comparison of radiation reduction techniques

Percutaneous nephrolithotomy confers the highest radiation to the urologist's hands compared to other urologic procedures. This study compares radiation exposure to the surgeon's hand and patient's body when utilizing three different techniques for needle insertion during renal access. Simulated percutaneous renal access was performed using a cadaveric patient and separate cadaveric forearm representing the surgeon's hand. Three different needle-holding techniques were compared: conventional glove (control), a radiation-attenuating glove, and a novel needle holder. Five 300-s fluoroscopy trials were performed per treatment arm. The primary outcome was radiation dose (mSv) to the surgeon's hand. The secondary outcome was radiation dose to the patient. One-way ANOVA and Tukey's B post-hoc tests were performed with p < 0.05 considered significant. Compared to the control (3.92 mSv), both the radiation-attenuating glove (2.48 mSv) and the needle holder (1.37 mSv) reduced hand radiation exposure (p < 0.001). The needle holder reduced hand radiation compared to the radiation-attenuating glove (p < 0.001). The radiation-attenuating glove resulted in greater radiation produced by the C-arm compared to the needle holder (83.49 vs 69.22 mGy; p = 0.019). Patient radiation exposure was significantly higher with the radiation-attenuating glove compared to the needle holder (8.43 vs 7.03 mSv; p = 0.027). Though radiation-attenuating gloves decreased hand radiation dose by 37%, this came at the price of a 3% increase in patient exposure. In contrast, the needle holder reduced exposure to both the surgeon's hand by 65% and the patient by 14%. Thus, a well-designed low-density needle holder could optimize radiation safety for both surgeon and patient.

Very low-dose computerized tomography for confirmation of urinary stone presence

PURPOSE

To determine whether a modified non-contrast very low-dose computed tomography (VLD-CT) protocol is applicable for confirmation of known urolithiasis.

METHODS AND MATERIALS

Consecutive adult patients with a CT scan showing urinary tract stone(s) between 6/2017-12/2018 were included. They were referred to a modified VLD-CT protocol if stone presence was equivocal or if stone location needed reassessment before an endourological interventional procedure. The scanned area was limited to the level of initial stone location caudally. Data on patients' demographics andbody mass index, were collected. The scanned length and radiation dose were calculated. Images were reviewed by two radiologists who assessed stone size and location. Follow-up reference standard included stone passage, surgical removal, and other imaging and clinical information.

RESULTS

Sixty-three patients [63 stones, mean BMI 28.7 (range 19-41.9)] were included. VLD-CTs revealed 31 stones in 31 patients, with a mean stone length of 5.5 mm. Fifteen stones remained at the same location, and 16 had migrated, of which two appeared in the bladder. Thirty-two stones were not observed on VLD-CT. The mean span scanned on the VLD-CT was 274 mm (± 80). The average radiation exposure was 1.47 mGy (range 1.09-3.3), and the absorbed dose was 0.77 mSv (range 0.39-1.43), compared to 10.24 mGy (range 1.75-28.9) and 7.87 mSv (range 1.44-18.5) in the previous scan. The mean radiation dose reduction between scans was 89%. On follow-up, all VLD-CT findings were confirmed.

CONCLUSION

A modified imaging protocol is applicable for confirmation of stone presence and location by utilizing very low-dose radiation exposure.

Techniques - Ultrasound-guided percutaneous nephrolithotomy: How we do it

Ultrasonography has emerged as an alternative to fluoroscopy for image-guided percutaneous nephrolithotomy (PCNL) in many countries. Compared to fluoroscopy-guided PCNL (F-PCNL), ultrasound-guided PCNL (US-PCNL) is easier to learn and reduces radiation exposure to patients and providers. Despite these advantages, uptake of ultrasound-guided PCNL (US-PCNL) in Canada has been almost nonexistent, largely because it is not incorporated into urologists' training. In this article, we seek to familiarize Canadian urologists with this approach by describing our step-by-step technique for US-PCNL. Additionally, we provide keys to successful implementation of this technique.

Risk of Radiation-Induced Cataracts: Investigation of Radiation Exposure to the Eye Lens During Endourologic Procedures

BACKGROUND

Due to new radiobiologic data, the International Commission on Radiological Protection recommends a dose limit of 20 mSv per year to the eye lens. Therefore, the IAEA International Basic Safety Standard and the European council directive 2013/59/EURATOM require a reduction of the annual dose limit from 150 to 20 mSv. Urologists are exposed to an elevated radiation exposure in the head region during fluoroscopic interventions, due to the commonly used overtable X-ray tubes and the rarely used radiation protection for the head. Aim of the study was to analyze real radiation exposure to the eye lens of the urologist during various interventions, during which the patient is in the lithotomy position.

MATERIALS AND METHODS

The partial body doses (forehead and apron collar) of the urologists and surgical staff were measured over a period of 2 months. 95 interventions were performed on Uroskop Omnia Max workplaces (Siemens Healthineers, Erlangen, Germany). Interventions were class-divided in less (stage I) and more complex (stage II) interventions. Two dosimeter-types were applied, well-calibrated electronic personal dosimeter Mk2 and self-calibrated thermoluminescent dosimeter-100H (both Thermo Fisher Scientific, Waltham, MA). The radiation exposure parameters were documented using the dose area product (DAP) and the fluoroscopy time.

RESULTS

The correlation between DAP and the apron dose of the urologist was in average 0.07 μSv per 1 μGym². The more experienced urologists yielded a mean DAP of 166 μGym² for stage I and 415 μGym² for stage II procedures. The interventionist was exposed with 10 μSv in mean outside the lead apron collar. The mean dose value of the eye lenses per intervention was ascertained to 20 μSv (mean DAP: 233 μGym²).

CONCLUSIONS

The study setup allows a differentiated and time-resolved measurement of the radiation exposure, which was found heterogeneous depending on intervention and surgeon. In this setting, ∼1000 interventions can be performed until the annual eye lens dose limit is achieved.