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

Radiation exposure of urologists during endourological procedures: a systematic review

INTRODUCTION

Ionizing radiation is used daily during endourological procedures. Despite the dangers of both deterministic and stochastic effects of radiation, there is a lack of knowledge and awareness among urologists. This study reviewed the literature to identify the radiation exposure (RE) of urologists during endourological procedures.

METHODS

A literature search of the Medline, Web of Science, and Google Scholar databases was conducted to collect articles related to the radiation dose to urologists during endourological procedures. A total of 1966 articles were screened. 21 publications met the inclusion criteria using the PRIMA standards.

RESULTS

Twenty-one studies were included, of which 14 were prospective. There was a large variation in the mean RE to the urologist between studies. PCNL had the highest RE to the urologist, especially in the prone position. RE to the eyes and hands was highest in prone PCNL, compared to supine PCNL. Wearing a thyroid shield and lead apron resulted in a reduction of RE ranging between 94.1 and 100%. Educational courses about the possible dangers of radiation decreased RE and increased awareness among endourologists.

CONCLUSIONS

This is the first systematic review in the literature analyzing RE to urologists over a time period of more than four decades. Wearing protective garments such as lead glasses, a thyroid shield, and a lead apron are essential to protect the urologist from radiation. Educational courses on radiation should be encouraged to further reduce RE and increase awareness on the harmful effects of radiation, as the awareness of endourologists is currently very low.

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.

[Radiation-induced cataract-an occult risk for urologists]

BACKGROUND

Radiation-induced cataracts represent a relevant risk to people occupationally exposed to radiation. The annual limit dose for the eye lens was reduced to 20 mSv per year by German legislation (radiation protect law StrlSchG 2017; 2013/59/Euratom) based on recommendation of International Commission on Radiation Protection (2011 ICRP) to avoid radiation-induced cataracts.

OBJECTIVES

Is there a risk of exceeding the annual limit dose for the eye lens in routine urological practice without special radiation protection for the head?

METHODS

As part of a prospective, monocentric dosimetry study, of 542 different urological, fluoroscopically guided interventions, the eye lens dose was determined using a forehead dosimeter (thermo-luminescence dosemeter TLD, Chipstrate) over a period of 5 months.

RESULTS

An average head dose of 0.05 mSv per intervention (max. 0.29 mSv) was found with an average dose area product of 485.33 Gy/cm². Significant influencing factors for a higher dose were a higher patient body mass index (BMI), a longer operation time, and a higher dose area product. The level of experience of the surgeon showed no significant influence.

DISCUSSION

With 400 procedures per year or an average of 2 procedures per working day, the critical annual limit value for the eye lenses or for the risk of radiation-induced cataract would be exceeded without special protective measures.

CONCLUSION

Consistently effective radiation protection of the eye lens is essential for daily work in uroradiological interventions. This may require further technical developments.

Radiation doses to the eye lenses of radiologic technologists who assist patients undergoing computed tomography

The present study aimed to determine the amount of radiation exposure to the eye lenses of radiologic technologists while assisting patients undergoing computed tomography imaging and the effects of wearing lead glasses on dose reduction. Monthly radiation doses were collected for 12 months. Dose quantities at a depth of 3 mm (H_p(3)) were measured at the neck using personal optically stimulated luminescence (OSL) dosimeters. We also estimated H_p(3) as converted air kerma using small OSL dosimeters at the neck and at six positions on the lead glasses near the eyes. The total dose-length product at the time of patient assistance was 53,341 mGy·cm/y. The H_p(3) from the personal dosimeter was 9.13 mSv/y and the highest dose recorded by the small OSL dosimeters attached outside the lead glasses was 8.47 mSv/y. The lead glasses reduced the radiation exposure by ~ 60%.

Radiation exposure of patients during endourological procedures: IAEA-SEGUR study

Fluoroscopy is increasingly used to guide minimally invasive endourological procedures and optimised protocols are needed to minimise radiation exposure while achieving best treatment results. This multi-center study of radiation exposure of patients was conducted by the South-Eastern European Group for Urolithiasis Research (SEGUR), in cooperation with the International Atomic Energy Agency. Seven clinical centers from the SEGUR group collected data for 325 procedures performed within a three-months period, including standard percutaneous nephrolithotomy (PCNL), mini PCNL, retrograde intrarenal surgery (RIRS), semirigid ureterorenoscopy (URS) and flexible URS. Data included: air kerma area product (P_KA), air kerma at the patient entrance reference point (K_a,r), fluoroscopy time (FT), number of radiographic images (N) and fluoroscopy pulse rate, as well as total procedure duration, size and location of stones. Data were centrally analysed and statistically compared. MedianP_KAvalues per center varied 2-fold for RIRS (0.80-1.79 Gy cm²), 7.1 fold for mini-PCNL (1.39-9.90 Gy cm²), 7.3 fold for PCNL (2.40-17.50 Gy cm²), 19 fold (0.13-2.51 Gy cm²) for semi-rigid URS and 29-fold for flexible URS (0.10-2.90 Gy cm²). LowerP_KAandK_a,rwere associated with use of lower FT,Nand lower fluoroscopy pulse rate. FT varied from 0.1 to 14 min, a small fraction of the total procedure time, ranging from 10 to 225 min. HigherNwas associated with higherP_KAandK_a,r. Higher medianP_KAin PCNL was associated with the use of supine compared to prone position. No correlation was found between the concrement size and procedure duration, FT,P_KAorK_a,r. Dose values for RIRS were significantly lower compared to PCNL. The maximumK_a,rvalue of 377 mGy was under the threshold for radiation induced skin erythema. The study demonstrated a potential for patient dose reduction by lowering FT andN, using pulsed fluoroscopy and beam collimation.

Radiation Exposure of Surgical Team During Endourological Procedures: International Atomic Energy Agency-South-Eastern European Group for Urolithiasis Research Study

Introduction: Fluoroscopy-guided endourology procedures require proper radiation protection to minimize radiation risk. This multicenter study aimed at investigating radiation protection practice and related radiation exposure of operating team members. Materials and Methods: Six endourology centers from the South-Eastern European Group for Urolithiasis Research answered questionnaires and collected data of 315 procedures performed within a 3-months period, with simultaneous measurement of dose to staff and dose area product (DAP) to patient. A pair of calibrated personal dosimeters, one for body and one for eye-lens dose, was worn by all key staff members. Dosimeters were centrally calibrated, measured, and analyzed. Results: The annual workload ranged from 173 to 865 procedures per center. Practice of personal dose monitoring and use of radiation protection shielding was found to be inconsistent. Lead aprons and thyroid collars were used by all, whereas protective eyewear was used in only half of centers. Due to the regular use of protective aprons, the whole-body dose of all 44 monitored staff members was safely below the regulatory dose limits. Eye-lens dose of 17 (14 urologists and 3 assisting staff) was above the dosimeter detection level, and dose per procedure varied from <10 to 63 μSv. The highest annual eye-lens dose of 13.5 mSv was found for the surgeon in the busiest department by using an over-the-couch X-ray tube without a ceiling suspended screen. Working closer to patient body with no protection resulted in a six-time higher eye-lens dose per DAP for a surgeon compared with others in the same center. Lower eye-dose per procedure was associated with lower DAP to patient and with the use of an under-the-couch tube, lower fluoroscopy pulse rate, collimation, fluoroscopy time, and acquired images. Conclusions: The study results call for the need to establish standard protocols about use of fluoroscopy during endourology procedures and to increase radiation protection knowledge and awareness of surgical staff.

[Effect of X-ray protective visors on the eye lens dose during ureteroscopy]

BACKGROUND AND OBJECTIVES

Eye lens radiation exposure during fluoroscopy-guided interventional procedures may result in occupational radiation-induced cataracts. We evaluated the eye lens radiation doses and the protective effect of X‑ray protective visors during ureteroscopic procedures.

MATERIALS AND METHODS

Eye lens doses were measured in front of and behind X‑ray protective visors using eye lens dosemeters during ureteroscopic procedures done by 4 different endourologic surgeons within a 12-week period. Background radiation dose, simultaneously measured with transport dosemeters, was subtracted. Measured eye lens doses below the detection limit of the eye lens dosemeters were adjusted to the detection limit of 0.028 mSv. Correlating the eye lens doses (ELD) to the dose-area-product (DAP) an ELD/DAP ratio was calculated. Applying this ELD/DAP ratio the potential reduction of the eye lens radiation dose was retrospectively calculated for all ureteroscopic procedures done within one year.

RESULTS

Within the 12-week period 76 ureteroscopies were done by the 4 endourologic surgeons. The accumulated eye lens radiation dose was 0.796 mSv in front of the X‑ray protective visors, and 0.338 mSv behind the X‑ray protective visors. Thus, the eye lens radiation exposure was reduced to at least 42% by using X‑ray protective visors. Considering the 215 documented ureteroscopies in our clinic in the year before starting the study, occupational radiation exposure to the eye lens would have been reduced by X‑ray protective visors from 4.090 to 1.737 mSv.

CONCLUSION

X‑ray protective visors can effectively reduce the radiation exposure to the eye lens during fluoroscopy-guided endourologic procedures and should be used especially by high-volume endourologic surgeons.

Radiation Dose to the Eye Lens Through Radiological Imaging Procedures at the Surgical Workplace During Trauma Surgery

Background: Due to the drastic reduction of the eye lens dose limit from 150 mSv per year to 20 mSv per year since 2018, the prospective investigation of the estimated dose of the eye lens by radiological imaging procedures at the surgical site during trauma surgery in the daily work process was carried out. This was also necessary because, as experience shows, with changes in surgical techniques, there are also changes in the use of radiological procedures, and thus an up-to-date inventory can provide valuable information for the assessment of occupationally induced radiation exposure of surgical personnel under the current conditions. Methods: The eye lens radiation exposure was measured over three months for five trauma surgeons, four hand surgeons and four surgical assistants with personalized LPS-TLD-TD 07 partial body dosimeters Hp (0.07). A reference dosimeter was deposited at the surgery changing room. The dosimeters were sent to the LPS (Landesanstalt für Personendosimetrie und Strahlenschutzausbildung) measuring institute (National Institute for Personal Dosimetry and Radiation Protection Training, Berlin) for evaluation after 3 months. The duration of the operation, occupation (assistant, surgeon, etc.), type of surgery (procedure, diagnosis), designation of the X-ray unit, total duration of radiation exposure per operation and dose area product per operation were recorded. Results: Both the evaluation of the dosimeters by the trauma surgeons and the evaluation of the dosimeters by the hand surgeons and the surgical assistants revealed no significant radiation exposure of the eye lens in comparison to the respective measured reference dosimeters. Conclusions: Despite the drastic reduction of the eye lens dose limit from 150 mSv per year to 20 mSv per year, the limit for orthopedic, trauma and hand surgery operations is well below the limit in this setting.

Radiation exposure in prone vs. modified supine position during PCNL: Results with an anthropomorphic model

INTRODUCTION

Radiation exposure during urological procedures is still of concern in the urology community. It has been reported that percutaneous nephrolithotomy (PCNL) in supine position has less irradiation, as the puncture is mostly done under ultrasound guidance. However, it can also be done under fluoroscopy guidance. Unfortunately, data on radiation exposure during PCNL is lacking since they are often drawn from generalization and extrapolation, or they do not evaluate new procedures or different positions. The aim of our study was to compare the radiation dose depending on the position of the surgeon during PCNL.

METHODS

A portable C-arm was used in standard mode (32 impulsions/second; 98 kV, 3.8 mA). Specific dosimeters were placed for lens, extremity, and torso. Anthropomorphic models and hand phantom models were used to reproduce the position of surgeon and patient (with same bone density as human) during PCNL in prone and modified supine position. Fluoroscopy time (FT) was six minutes to obtain higher exploitable signal, and the results are given for a FT of three minutes (more realistic). Ten percent of the FT is done with an angulation of 15 degrees and the rest in anteroposterior position.

RESULTS

The equivalent doses (ED) are given in uSV (uncertainty k=2). During the modified supine position: neck, lens, right index finger, left thumb, and index finger received EDs of 99 (20%), 62 (18%), 437 (10%), 112 (12%), and 204 (10%), respectively. In a prone position, the phantom received ED on the neck, lens, right thumb and index finger, left thumb and index finger of 85 (20%), 92 (12%), 401 (10%), 585 (10%), 295 (10%), and 567 (10%), respectively. In both positions, the right hand seems more exposed than the left hand.

CONCLUSIONS

The effective dose is 1.5- and 1.3-fold higher for lens and extremities, respectively, in prone position PCNL compared to modified supine position. Both positions are still well below the recommended limit for professional exposure.