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Effect of Protective Lead Curtains on Scattered Radiation Exposure to the Operator During Ureteroscopy for Stone Disease: A Controlled Trial
Accepted Manuscript Title: Effect of Protective Lead Curtains on Scattered Radiation Exposure to the Operator during Ureteroscopy for Stone Disease: a Controlled Trial Author: Takaaki Inoue, Atsushi Komemushi, Takashi Murota, Takashi Yoshida, Makoto Taguchi, Hidefumi Kinoshita, Tadashi Matsuda PII: DOI: Reference:
S0090-4295(17)30786-0 http://dx.doi.org/doi: 10.1016/j.urology.2017.07.036 URL 20585
To appear in:
Urology
Received date: Accepted date:
18-6-2017 28-7-2017
Please cite this article as: Takaaki Inoue, Atsushi Komemushi, Takashi Murota, Takashi Yoshida, Makoto Taguchi, Hidefumi Kinoshita, Tadashi Matsuda, Effect of Protective Lead Curtains on Scattered Radiation Exposure to the Operator during Ureteroscopy for Stone Disease: a Controlled Trial, Urology (2017), http://dx.doi.org/doi: 10.1016/j.urology.2017.07.036. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Effect of protective lead curtains on scattered radiation exposure to the operator during ureteroscopy for stone disease: a controlled trial
Running title: scattered radiation exposure and ureteroscopy
Takaaki Inoue, MD1), Atsushi Komemushi, MD, PhD2), Takashi Murota, MD1), Takashi Yoshida, MD3), Makoto Taguchi, MD3), Hidefumi Kinoshita, MD, PhD3), and Tadashi Matsuda, MD, PhD3)
Department of Urology and Stone Center, General Medical Center, Kansai Medical University, Osaka, Japan1) Department of Radiology, General Medical Center, Kansai Medical University, Osaka, Japan2) Department of Urology, Hirakata Hospital, Kansai Medical University, Osaka, Japan3)
Corresponding author: Takaaki Inoue, MD Department of Urology, Hirakata Hospital, Kansai Medical University, Hirakata Shinmachi 2-3-1, Hirakata, Osaka 573-1191, Japan 1 Page 1 of 26
Tel: +81-072-804-0101 Fax: +81-072-804-2068 E-mail: [email protected]
E-mail address for all authors: Takaaki Inoue, MD: [email protected] Atsushi Komemushi, MD, PhD: [email protected] Takashi Murota, MD: [email protected] Takashi Yoshida, MD: [email protected] Makoto Taguchi, MD: [email protected] Hidefumi Kinoshita, MD, PhD: [email protected] Tadashi Matsuda, MD, PhD: [email protected]
Abstract count: 339 words Main text (Introduction to Conclusions): 2821 words Key words: scattered radiation exposure, ureteroscopy, protective shield 2 Page 2 of 26
Abstract Objectives: To evaluate a reduction in total radiation dose to the operator during ureteroscopy (URS) for stone disease by using protective lead curtains. Methods: Two studies were planned to compare scattered radiation doses without (n-LC group) and with protective lead curtains (LC group). In study 1, we measured the spatial distribution of the scattered radiation dose using a human phantom simulating URS for stone management for both groups. In study 2, we prospectively randomized patients undergoing treatment for stone disease with URS into n-LC (n = 62) and LC group (n = 61). Scattered radiation dose to the operator during URS were recorded. Primary endpoint was a reduction in effective dose to the operator. Results: In study 1, there was an 80% reduction in dose at the operator area between the n-LC and LC groups. In study 2, the mean effective doses to the operator in the n-LC and LC groups were 0.33 ± 0.85 and 0.08 ± 0.08 μSv (p = 0.003). The mean doses measured at the neck and waist outside of the lead apron and at the chest inside of the lead apron in the n-LC and LC groups were 2.22 ± 4.56 vs 0.84 ± 0.77 μSv (p = 0.008), 5.48± 12.4 vs 0.76 ± 0.89 μSv (p = 0.001), and 0.10 ± 0.47 vs 0.00 ± 0.00 μSv (p = 0.001), respectively. Conclusion: These curtains are useful for protecting the operator from scattered 3 Page 3 of 26
radiation, resulting in reduction of total radiation exposure for surgeons performing URS.
INTRODUCTION Current development of endoscopic technology, lithotripters, such as holmium lasers, and some basket devices have expanded indications of retrograde and antegrade endoscopic therapy for managing urolithiasis. This technology has also resulted in minimum invasive therapy. Endourological procedures, such as retrograde pyelography, retrograde
intrarenal
surgery,
percutaneous
nephrolithotomy
(PCNL),
and
extracorporeal shock wave lithotripsy among the urological field, are mostly performed under fluoroscopy. However, patients, surgeons, and medical staff during these procedures have an increased chance of radiation exposure. Radiation exposure is linked to loss of hair, erythema, cataracts, and malignancy, including thyroid cancer and leukemia 1). Therefore, even if the risk of harmful effects of occupational radiation exposure is relatively small, doses exceeding the standard limits likely carry a small, short-term health risk. Occupational radiation exposure of surgeons and medical staff during fluoroscopic 4 Page 4 of 26
procedures mostly arises because of scattered radiation 2). Therefore, surgeons and medical staff who perform procedures under fluoroscopy need to note where scattered radiation comes from, and how many scattered radiation doses they are exposed to by procedures. The international commission on radiological protection (ICRP) has advocated that all physicians must always adopt the principle of limiting radiation exposure to “as low as reasonably achievable” (ALARA)2). Therefore, we aimed to investigate the spatial distribution of scattered radiation doses and evaluate the reduction in total radiation dose to the operator during ureteroscopy (URS) for stone disease by using protective lead curtains.
MATERIAL AND METHODS Spatial dosimetry in the operating room study (study 1) Measurement of the scattered radiation dose was performed in the operating room for management of stones. A C-arm (Philips, BV Libra, Italy), X-ray image monitor (Philips, BV Libra, Italy), URS image monitor (Olympus, Japan), and holmium laser (Odyssey 30; Convergent) were arranged in the operating room. An anthropomorphic phantom was positioned and fixed on an operating table (Fig. 1-A, B, C). The X-ray tube (Philips, BV Libra, Italy) was under the table. The table height was set at 100 cm, 5 Page 5 of 26
which was comfortable for the surgeon. The X-ray tube height was set at 50 cm, which was easy to move a C-arm not to interfere the column and foundation of operating table. These heights were constantly maintained at the same heights as in real URS procedures. Measurement of the scattered radiation dose was performed at 50, 100, 150, and 200 cm with a focus on the X-ray tube in eight directions by using an ionization chamber (Fig. 1-D). There was continuous irradiation from the X-ray tube to the phantom for 1 minute. The ionization chamber, which measures the scattered radiation dose per minute (μSv/min), was set at 100 cm in height to match the waist height of the surgeon. These measurements were performed between two groups, including without and with protective lead curtains. These curtains were positioned and secured using double sided tape at the operating table end, both sides of the table, and the image intensifier (Fig. 1-D). The protective lead curtains were manufactured in-house with 0.35-mm lead aprons of L-size weighed 3.1 kg that were cut.
Radiation exposure dosimetry study (study 2) Design This study included all URS procedures for upper urinary stones that were performed between April 2014 and May 2015. A total of 123 URS procedures were 6 Page 6 of 26
included and randomly divided into a non-protective lead curtain group (n-LC group; 62 cases) and a protective lead curtain group (LC group; 61 cases) under simple randomization by using the envelope method (Supplementary Fig.1). This study was approved by the ethics committee of Kansai Medical University General Medical Center (UMIN No.; R000029628). All patients provided written informed consent. Patients in whom performing the lithotomy position or general anesthesia was impossible were excluded. The primary endpoint was a reduction in effective dose to the operator between the n-LC and LC groups. Other endpoints were the radiation exposure dose of the neck and waist outside of the lead apron, and at the chest inside of the lead apron to the operator. Arrangement of equipment The equipments were arranged in the operating room (Fig. 1-E). The patients were positioned in the lithotomy position. URS procedures for stone management were performed under general anesthesia and continuous irradiation from the X-ray tube by a single surgeon (TI) who experienced over than 200 URS procedures. The X-ray tube was under the table. The table height was set at 100 cm, which was comfortable for the surgeon. The X-ray tube height was set at 50 cm, which was easy to move a C-arm not to interfere the column and foundation of operating table. Protective lead curtains were 7 Page 7 of 26
positioned at the operating table end, both sides of the table, and the image intensifier (Fig. 1-F). The protective lead curtains were manufactured in-house with 0.35-mm lead aprons of L-size weighed 3.1 kg that were cut. Measurement of the scattered radiation exposure dose to the operator during URS was performed in the n-LC and LC groups. The operator wore protective clothes, including a 0.35-mm lead apron, a thyroid shield, and eye glasses with lead lining. Electronic pocket radiation dosimeters (PDM127; Hitachi Aloka Co., Ltd., Tokyo, Japan) were attached at the neck and at the waist outside of the lead apron and at the chest inside of the lead apron (Fig 2).
Evaluation of radiation exposure to the operator Data, such as the patient’s age, sex, body mass index side of stones, stone location, stone burden, operative time, fluoroscopic time, and stone-free rate, were collected. The size of simple stones was measured by the long axis of the stone, and the size of multiple renal stones was measured by adding the length of the longest axis of each stone. The neck and waist exposure dose outside of the lead apron (μSv), the chest exposure dose inside of the lead apron (μSv), and the effective dose (μSv) to the operator from scattered radiation were measured. Based on the 1990 recommendations of the International Commission on Radiological Protection and the Nuclear Safety 8 Page 8 of 26
Technology Center in Japan, the effective dose (ED) as calculated using the following formula: ED = 0.11 Ha + 0.89 Hb (for calculating related to external exposure when exposure is non-uniform) (Ha: 1-cm dose equivalent at the neck level on the outside of the lead apron; Hb: 1-cm dose equivalent at the chest level inside of the lead apron) 3)4)5). These parameters were compared between the n-LC and LC groups.
Statistical analysis Sample size was calculated based on our results of study 1, which indicated a reduction of 75% in exposure dose at waist level to the operator when using lead curtains. Among 82 patients, 41 per arm would be required to detect a significant difference between the n-LC and LC groups, with 80% power. We recruited about 60 patients in each group for covering the range of error and safety. All data are shown as mean ± standard deviation (SD). All collected data were analyzed using SPSS version 21 (IBM Corp., Armonk, NY, USA). Comparison between the n-LC and LC groups was performed using the Pearson chi-square test and theStudent’s t-test. A two-sided p value of < 0.05 was considered statistically significant.
RESULTS 9 Page 9 of 26
Spatial dosimetry in the operating room study (study 1) The scattered radiation dose without protective lead curtains in eight directions decreased as the distance from the X-ray tube increased (Supplementary Figure 2-A). Scattered radiation doses of 100 and 150 cm in the operator area where URS procedures were performed were 2.2 μSv/min and 1.1 μSv/min, respectively. However, scattered radiation doses of 100 and 150 cm in the operator area with protective lead curtains were 0.51 μSv/min and 0.23 μSv/min. Protective lead curtains led to a reduction of 75–80% in the scattered radiation dose compared with without lead curtains (Supplementary Figure 2-B).
Radiation exposure dosimetry study (study 2) A total of 62 patients in the n-LC group and 61 in the LC group were analyzed. Baseline patient and stone characteristics were not significantly different between the groups. Mean fluoroscopy time in the n-LC group as 116.4 ± 102.1 sec was significantly lower than that in the LC group as 118.5 ± 60.9 sec (p = 0.047, Table 1). The scattered radiation exposure doses to the operator during URS in the n-LC and LC groups are shown in Fig 3. The mean effective dose to the operator was significantly higher in the n-LC group than in the LC group (0.33 ± 0.85 vs 0.08 ± 0.08 μSv, p = 10 Page 10 of 26
0.003). The mean doses that were measured at the neck and waist outside of the lead apron, and at the chest inside of the lead apron to the operator were significantly higher in the n-LC group than in the LC group (2.22 ± 4.56 vs 0.84 ± 0.77 μSv, p = 0.008; 5.48± 12.4 vs 0.76 ± 0.89 μSv, p = 0.001; 0.10 ± 0.47 vs 0.00 ± 0.00 μSv, p = 0.001, respectively). The rate of reduction in the scattered radiation exposure dose in the LC group was 74% for the effective dose, 62.1% in the neck, and 86.1% in the waist outside of the apron, and 100% in the chest outside of the apron compared with the n-LC group.
COMMENT In the present study, protective lead curtains were effective devices for protecting the operator from scattered radiation exposure during URS. To the best of our knowledge, this study is the first to include basic spatial measurement of the scattered radiation dose using a human phantom simulating URS and the scattered radiation exposure dose to the operator during URS according to lead protective curtains. A major source of occupational radiation exposure is caused by direct radiation that is generated in the fluoroscopy field between an X-ray tube and an image intensifier. Another major source is scattered radiation that is produced from interaction of the primary radiation beam with the patient’s body and the operating table. Radiation 11 Page 11 of 26
exposure of surgeons and medical staff during procedures mostly arises because of scattered radiation 2). This scattered radiation is divided into two types: backward scattering and forward scattering. The backward scattering dose is approximately 20-fold as strong as the forward scattering dose 6). In this study, protective lead curtains that were mounted at the operating table end and at both sides of the table were used for inhibiting backward scattering. Protective lead curtains that were positioned at the image intensifier were used for inhibiting forward scattering. Consequently, the scattered radiation dose with protective lead curtains in the operator area was decreased by 75–80% compared with no protective lead curtains. Politi and colleagues studied radiation exposure of the surgeon during transradial percutaneous coronary angiography7). Radiation exposure was lower in the group with the Radpad shielding device, which is composed of a tungsten antimony lead-free material, than in the group without this device (282.8 ± 32.55 vs 367.8 ± 105.4 μSv, p<0.001). This resulted in a total dose reduction of 23% with this device7). Gilligan and associates found that radiation exposure of the surgeon using a lead Plexiglas screen shield and Radpad during transradial percutaneous coronary angiography decreased the total radiation dose by 52% (15.4 μSv per case vs 7.3 μSv per case, p<0.001) 8). In the urological field, Yang and co-workers reported that radiation exposure of the surgeon 12 Page 12 of 26
during PCNL was decreased by 71.2% at a distance of 50 cm from the image intensifier by using a radiation shield over the operative table 9). Zoller and co-workers reported that a face protection shield was effective in reducing eye lens radiation exposure during URS 10). However, there have only been a few reports on radiation exposure during URS. The occupational radiation exposure dose limit is defined as 20 mSv per year by the ICRP 11). However, Kusuba et al observed chromosomal aberrations in peripheral blood lymphocytes of Croatian hospital staff who were occupationally exposed to low levels of ionizing radiation in 2008 12). Another study showed that low levels of chronic occupational exposure to ionizing radiation causes an increase in micronuclei frequency in chromosomes, which is a biomarker of chromosomal damage, genome instability, and cancer risk, in 2010 13). Thyroid cancer was increased as a direct result of constant exposure to ionizing radiation at a low level of exposure among Australian orthopedic surgeons in 1998 14). Roguin et al reported 31 interventional physicians with brain and neck cancer who were chronically exposed to ionizing radiation during their fluoroscopic procedures in 2013 15). They found a disproportionate occurrence of tumors on the left side of the brain in 22 cases. The ICRP advocates the ALARA principle of limiting radiation exposure for optimization of protection and desire to 13 Page 13 of 26
carry out the action 16)17). In modern radiation protection practice, active personal dosimeters are absolutely essential operational tools to satisfy the ALARA principle 18). However, most urologists may have an insufficient perception of radiation protection for themselves. A previous study showed that although 84.4% of urologists who were chronically exposed to ionizing radiation wore lead aprons, only 53.9% wore a thyroid shield and 27.9% wore eye glasses with lead lining 19). Moreover, only 23.6% of urologists put on a dosimeter 19). Soylemez and co-workers reported that 75.2% of urologists with occupational radiation exposure wore lead aprons 20). However, only 46.6% wore a thyroid shield and 23.1% wore eye glasses with lead lining. Moreover, only 26.1% of urologists put on a dosimeter 20). Awareness of physicians for occupational radiation exposure in the urological field still remain low 21). Although the risks of harmful effects of occupational radiation exposure may be relatively small, they should not be ignored. Time, distance, and shielding are generally critical factors for determining the level of radiation exposure 11). Shielding is usually performed by using protective clothes for protecting oneself. The standard lead protection protocol requires the use of 0.35-mm lead aprons and thyroid shields for the operating surgeon and 0.25-mm lead aprons for other personnel 22). However, protection from scattered radiation by 14 Page 14 of 26
protective clothes is incomplete, especially to the arms, eyes, and brain. Additionally, performing procedures with these clothes under fluoroscopy causes fatigue for surgeons because of the weight of clothes and difficulty of movement, resulting in uncomfortable circumstances 23). Soylemez and co-workers reported that for urologists, wearing protective clothes is not practical and causes deterioration of the surgeon’s ergonomics 20). Therefore, our study focused on shielding of scattered radiation using protective lead curtains on the operative table. In this study, we evaluated the effect of non-uniform radiation exposure for the whole body because scattered radiation affects not only specific parts of the body, but also the whole body. Therefore, we used the ED for measurement, which was calculated using a formula that was based on the 1990 recommendations of the International Commission on Radiological Protection and the Nuclear Safety Technology Center in Japan 3)4)5)24). Although the effective dose using protective lead curtains did not result in 0 μSv in our study, the effective dose to the operator during URS was significantly decreased. In our study, the operator wore a lead apron, thyroid shield, and eye glasses with lead lining for protecting from scattered radiation exposure. Nevertheless, the operator was exposed to radiation in the inside of the lead apron without protective lead curtains. 15 Page 15 of 26
Komemushi and associates also reported that the radiation exposure dose to the operator inside of the lead apron was 0.48–0.65 μSv per procedure in interventional radiology procedures 24). Furthermore, some investigators have found that the radiation exposure dose to the operator at waist level is higher than that at the neck level at an X-ray tube under the operating table 25)26). In our study, the radiation exposure dose to the operator at waist level was 2.5 times as much as the neck level. Even if the radiation exposure dose is small, this may cause major issues of fertility for men and women. Only wearing protective clothes does not ensure complete safety. Therefore, surgeons should consider further safe-guards to protect themselves in accordance with the ALARA principle. In the present study, the radiation exposure dose to the operator inside of the lead apron with protective lead curtains was below the detectable limit. Possible limitations of this study include the following. The fluoroscopic time during URS was significantly longer in the LC group than in the n-LC group. However, despite of long fluoroscopic time in LC group, the radiation exposure dose to the operator was significantly lower. Furthermore, we did not pay attention to the setting and position of the equipment, such as using pulsed fluoroscopy, increasing collimation of the primary beam, maximizing the distance between the X-ray tube and the patient, and minimizing the distance between patients and the image intensifier 27)28). Elkoushy and 16 Page 16 of 26
co-workers reported that pulsed fluoroscopy has been associated with 60% reduction in fluoroscopy time 27). Damien and co-workers found that pulsed fluoroscopy reduced radiation dose by 64% compared with continuous fluoroscopy 29). However, a C-arm used in this study did not have a function of pulsed fluoroscopy mode and collimation. If these factors are arranged, further reduction of radiation exposure to the operator may be expected. Furthermore, the surgeon operated the image intensifier during URS procedures in this study. However, one investigator reported that radiographer delivered fluoroscopy could reduce the exposure time to ionizing radiation for some urological procedures including retrograde pyelography and semi-rigid URS, but not for flexible URS procedures. The radiographers in our institution could not help the fluoroscopy during URS procedures in operation room because of lack of workforce 30). Regardless of these limitations, using protective lead curtains during URS not only decreases the radiation exposure dose to the operator, but may also improve surgeons’ ergonomics because of the light weight of protective clothes.
CONCLUSION Protective lead curtains decrease the dose of spatially scattered radiation in the 17 Page 17 of 26
operator area. These curtains are useful devices for protecting the operator from scattered radiation, resulting in a reduction in total radiation exposure for URS surgeons.
Author Disclosure Statement No competing financial interests exist.
References 1. Linet MS, Kim KP, Miller DL, et al: Historical review of occupational exposures and cancer risks in medical radiation workers. Radiat Res 174: 793-808, 2010. 2. Hellawell GO, Mutch SJ, Thevendran G, et al: Radiation exposure and the urologist: what are the risks?. J Urol 174: 948-52, 2005. 3. ICRP Recommendations of the international commission on radiological protection. ICRP Publication 60 Ann ICRP 1991; 21 4. Komemushi A, Tanigawa N, Kariya S, et al: Radiation exposure to operators during vertebroplasty. JVIR 16: 1327-32, 2005. 5. Methods for measuring effective dose equivalent from external exposure. U. S. 18 Page 18 of 26
Nuclear Regulatory Commission Regulatory guide 8.40, 2010; 1-8 6. Lee K, Lee KM, Park MS, et al: Measurements of surgeon’s exposure to ionizing radiation dose during intraoperative use of C-arm fluoroscopy. Spine 37: 1240-4, 2012. 7. Politi L, Biondi-Zoccai G, Nocetti L, et al: Reduction of scatter radiation during transradial percutaneous coronary angiography: A randomized trial using a lead-free radiation shield. Cathet Cardiovasc Interv 79: 97-102, 2012. 8. Gilligan P, Lynch J, Eder H, et al: Assessment of clinical occupational dose reduction effect of a new interventional cardiology shield for radial access combined with a scatter reducing drape. Cathet Cardiovasc Interv 86: 935-40, 2015. 9. Yang RM, Morgan T, Bellman GC. Radiation protection during percutaneous nephrolithotomy: a new urologic surgery radiation shield. J Endourol 16: 727-31, 2002. 10. Zoller G, Figel M, Denk J, et al. Eye lens radiation exposure during ureteroscopy with and without a face protection shield: Investigations on a phantom model. Urologe A 55: 364-9, 2016. 11. Duran A, Hian SK, Miller DL, et al: Recommendations for occupational radiation protection in interventional cardiology. Cathet Cardiovasc Interv 82: 29-42, 2013. 19 Page 19 of 26
12. Kasuba V, Rozgaj R, Jazbec A: Chromosome aberrations in peripheral blood lymphocytes of Croatian hospital staff ocuppationally exposed to low level of ionizing radiation. Arh Hig Rada Toksikol 59: 251-9, 2008. 13. Eken A, Aydin A, Erdem O, et al: Cytogenetic analysis of peripheral blood lymphocytes of hospital staff occupationally exposed to low doses of ionizing radiation. Toxicol Ind Health 26: 273-80, 2010. 14. Dewey P, Incoll I: Evaluation of thyroid shield for reduction of radiation exposure to orthopaedic surgeons. Aust N.Z J Surg 68: 635-6, 1998. 15. Roguin A, Goldstein J, Bar O, et al: Brain and neck tumors among physicians performing interventional procedures. Am J Cardiol 111: 1368-72, 2013. 16. Recommendations of the Internationa Commission on Radiological Protection (Revised December, 1954): Br J Radiol. Suppl 6, 1955 17. Implications of Commission recommendations that doses be kept as low as readily achievable. A report of ICRP Committee 4, ICRP Publication 22, Pergamon press, 1973 18. Bolognese-Milsztajn T, Ginjaume M, Luszik-Bhadra M, et al: Active personal dosimeters for individual monitoring and other new development. Radiat Prot Dosimetry 112: 141-68, 2004. 20 Page 20 of 26
19. Borges CF, Reggio E, Vicentini FC, et al: How are we protecting ourselves from radiation exposure? A nationwide survey. Int Urol Nephrol 47: 271-4, 2015. 20. Soylemez H, Altunoluk B, Bozkurt Y, et al: Radiation exposure-urologists take it seriously in turkey? J Urol 187: 1301-5, 2012. 21. Adem T, Alparslan A, Nimet A, et al: Are the urology operating room personnel aware about the ionizing radiation ? Int Braz J Urol 41: 982-9, 2015. 22. Medical and Dental Guidance Notes: A Good Practice Guide on all Aspects of Ionising Radiation Protection in the Clinical Environment. York: Institute of Physics and Engineering in Medicine, 2002 23. Dehmer GJ: Occupational hazards for interventional cardiologists. Catheter Cardiovasc Interv 68: 974-6, 2006. 24. Komemushi A, Suzuki S, Sano A: Radiation dose of nurse during IR procedures: a controlled trial evaluating operator alerts before nursing tasks. J Vasc Interv Radiol 25: 1195-9, 2014. 25. Ahn Y, Kim CH, Lee JH, et al: Radiation exposure to the surgeon during percutaneous endoscopic lumber discectomy: a prospective study. Spine (Phila Pa 1976) 38: 617-25, 2013. 26. Kim KP, Miller DL, Balter S, et al: Occupational radiation doses to operators 21 Page 21 of 26
performing cardiac catheterization procedures. Health Phys 94: 211-27, 2008. 27. Elkoushy MA, Shahrour W, Andonian A: Pulsed fluoroscopy in ureteroscopy and percutaneous nephrolithotomy. Urology 79: 1230-5, 2012. 28. Horsburgh BA, Huggins M: A study of occupational radiation dosimetry during fluoroscopically guided simulated urological surgery in the lithotomy position. J Endourol 30: 1312-20, 2016. 29. Damine LS, Jonathan PH, Gideon DR et al. Radiation exposure during continuous and pulsed fluoroscopy. J Endourol 27: 384-8, 2013. 30. Martin J, Hennessey DB, Young M, et al. Radiographer delivered fluoroscopy reduces radiation exposure during endoscopic urological procedures. Ulster Med J 2016; 85 :8-12.
22 Page 22 of 26
Figure 1: Setting of measuring equipment and spatial distribution of the radiation dose in the operating room. The arrows indicate (A) the anthropomorphic phantom, (B) the scattered ionization chamber, and (C) protective lead curtains. (D) Equipment layout and range of measurement of spatially scattered radiation. Dot range and circles indicate protective lead curtains on the operating table and the image intensifier. (E) Equipment layout during URS. Dot range and circles indicate protective lead curtains on the operating table and image intensifier during URS. (F) Protective lead curtains and patients in the lithotomy position during URS.
Figure 2: Measurement methods of the radiation exposure dose to the operator. (A) Wearing pocket dosimeters (PDM127), (B) at the neck and (C) at the waist outside of the lead apron, and (D) at the chest inside of the lead apron.
Figure 3: Radiation exposure doses to the operator between the n-LC group and LC group during URS.
23 Page 23 of 26
Supplementary Figure 1: Consort chart.
Supplementary Figure 2: (A) Spatial distribution of the scattered radiation dose without protective lead curtains. (B) Spatial distribution of the scattered radiation dose with protective lead curtains.
24 Page 24 of 26
Table 1: Patient and stone characteristics, and surgical outcome according to protective lead curtains n-LC group
LC group
n = 62
n = 61
Age, years
62.9 ± 14.3
62.1 ± 13.0
Sex, n (%)
M: 33 (53.2) F: 29 (46.7)
M: 37 (60.6) F: 24 (39.3) 0.424
23.5 ± 4.4
23.9 ± 3.4
0.474
R: 28 (45.1) L: 29 (46.7)
R: 26 (42.6) L: 29 (47.5)
0.422
BMI, kg/m
2
Stone side, n (%)
p value* 0.498
B: 6 (9.8) B: 4 (6.4) Stone location, n (%)
39 (62.9)
30 (49.1)
11 (17.7)
20 (32.7)
proximal ureter
5 (8.0)
4 (6.5)
middle ureter
7 (11.2)
7 (11.4)
Mean stone burden, mm
17.1 ± 9.4
17.5 ± 8.3
0.475
Mean operative time, min
74.9 ± 40.4
65.1 ± 30.9
0.18
Mean fluoroscopic time, s
116.4 ± 102.1
118.5 ± 60.9
0.047
Stone-free rate, n (%)
59 (95.1)
58 (95.0)
0.984
Complication, n (%)
0 (0)
1 (1.6)
0.311
kidney
0.421
distal ureter
Data are presented as mean ± standard deviation or n (%).
25 Page 25 of 26
M=male, F=female, BMI = body mass index, R = right, L = left, B = bilateral. *Pearson chi-square test, Student’s t-test. • Stone-free was defined as residual stones <1 mm in diameter.
26 Page 26 of 26
S0090-4295(17)30786-0 http://dx.doi.org/doi: 10.1016/j.urology.2017.07.036 URL 20585
To appear in:
Urology
Received date: Accepted date:
18-6-2017 28-7-2017
Please cite this article as: Takaaki Inoue, Atsushi Komemushi, Takashi Murota, Takashi Yoshida, Makoto Taguchi, Hidefumi Kinoshita, Tadashi Matsuda, Effect of Protective Lead Curtains on Scattered Radiation Exposure to the Operator during Ureteroscopy for Stone Disease: a Controlled Trial, Urology (2017), http://dx.doi.org/doi: 10.1016/j.urology.2017.07.036. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Effect of protective lead curtains on scattered radiation exposure to the operator during ureteroscopy for stone disease: a controlled trial
Running title: scattered radiation exposure and ureteroscopy
Takaaki Inoue, MD1), Atsushi Komemushi, MD, PhD2), Takashi Murota, MD1), Takashi Yoshida, MD3), Makoto Taguchi, MD3), Hidefumi Kinoshita, MD, PhD3), and Tadashi Matsuda, MD, PhD3)
Department of Urology and Stone Center, General Medical Center, Kansai Medical University, Osaka, Japan1) Department of Radiology, General Medical Center, Kansai Medical University, Osaka, Japan2) Department of Urology, Hirakata Hospital, Kansai Medical University, Osaka, Japan3)
Corresponding author: Takaaki Inoue, MD Department of Urology, Hirakata Hospital, Kansai Medical University, Hirakata Shinmachi 2-3-1, Hirakata, Osaka 573-1191, Japan 1 Page 1 of 26
Tel: +81-072-804-0101 Fax: +81-072-804-2068 E-mail: [email protected]
E-mail address for all authors: Takaaki Inoue, MD: [email protected] Atsushi Komemushi, MD, PhD: [email protected] Takashi Murota, MD: [email protected] Takashi Yoshida, MD: [email protected] Makoto Taguchi, MD: [email protected] Hidefumi Kinoshita, MD, PhD: [email protected] Tadashi Matsuda, MD, PhD: [email protected]
Abstract count: 339 words Main text (Introduction to Conclusions): 2821 words Key words: scattered radiation exposure, ureteroscopy, protective shield 2 Page 2 of 26
Abstract Objectives: To evaluate a reduction in total radiation dose to the operator during ureteroscopy (URS) for stone disease by using protective lead curtains. Methods: Two studies were planned to compare scattered radiation doses without (n-LC group) and with protective lead curtains (LC group). In study 1, we measured the spatial distribution of the scattered radiation dose using a human phantom simulating URS for stone management for both groups. In study 2, we prospectively randomized patients undergoing treatment for stone disease with URS into n-LC (n = 62) and LC group (n = 61). Scattered radiation dose to the operator during URS were recorded. Primary endpoint was a reduction in effective dose to the operator. Results: In study 1, there was an 80% reduction in dose at the operator area between the n-LC and LC groups. In study 2, the mean effective doses to the operator in the n-LC and LC groups were 0.33 ± 0.85 and 0.08 ± 0.08 μSv (p = 0.003). The mean doses measured at the neck and waist outside of the lead apron and at the chest inside of the lead apron in the n-LC and LC groups were 2.22 ± 4.56 vs 0.84 ± 0.77 μSv (p = 0.008), 5.48± 12.4 vs 0.76 ± 0.89 μSv (p = 0.001), and 0.10 ± 0.47 vs 0.00 ± 0.00 μSv (p = 0.001), respectively. Conclusion: These curtains are useful for protecting the operator from scattered 3 Page 3 of 26
radiation, resulting in reduction of total radiation exposure for surgeons performing URS.
INTRODUCTION Current development of endoscopic technology, lithotripters, such as holmium lasers, and some basket devices have expanded indications of retrograde and antegrade endoscopic therapy for managing urolithiasis. This technology has also resulted in minimum invasive therapy. Endourological procedures, such as retrograde pyelography, retrograde
intrarenal
surgery,
percutaneous
nephrolithotomy
(PCNL),
and
extracorporeal shock wave lithotripsy among the urological field, are mostly performed under fluoroscopy. However, patients, surgeons, and medical staff during these procedures have an increased chance of radiation exposure. Radiation exposure is linked to loss of hair, erythema, cataracts, and malignancy, including thyroid cancer and leukemia 1). Therefore, even if the risk of harmful effects of occupational radiation exposure is relatively small, doses exceeding the standard limits likely carry a small, short-term health risk. Occupational radiation exposure of surgeons and medical staff during fluoroscopic 4 Page 4 of 26
procedures mostly arises because of scattered radiation 2). Therefore, surgeons and medical staff who perform procedures under fluoroscopy need to note where scattered radiation comes from, and how many scattered radiation doses they are exposed to by procedures. The international commission on radiological protection (ICRP) has advocated that all physicians must always adopt the principle of limiting radiation exposure to “as low as reasonably achievable” (ALARA)2). Therefore, we aimed to investigate the spatial distribution of scattered radiation doses and evaluate the reduction in total radiation dose to the operator during ureteroscopy (URS) for stone disease by using protective lead curtains.
MATERIAL AND METHODS Spatial dosimetry in the operating room study (study 1) Measurement of the scattered radiation dose was performed in the operating room for management of stones. A C-arm (Philips, BV Libra, Italy), X-ray image monitor (Philips, BV Libra, Italy), URS image monitor (Olympus, Japan), and holmium laser (Odyssey 30; Convergent) were arranged in the operating room. An anthropomorphic phantom was positioned and fixed on an operating table (Fig. 1-A, B, C). The X-ray tube (Philips, BV Libra, Italy) was under the table. The table height was set at 100 cm, 5 Page 5 of 26
which was comfortable for the surgeon. The X-ray tube height was set at 50 cm, which was easy to move a C-arm not to interfere the column and foundation of operating table. These heights were constantly maintained at the same heights as in real URS procedures. Measurement of the scattered radiation dose was performed at 50, 100, 150, and 200 cm with a focus on the X-ray tube in eight directions by using an ionization chamber (Fig. 1-D). There was continuous irradiation from the X-ray tube to the phantom for 1 minute. The ionization chamber, which measures the scattered radiation dose per minute (μSv/min), was set at 100 cm in height to match the waist height of the surgeon. These measurements were performed between two groups, including without and with protective lead curtains. These curtains were positioned and secured using double sided tape at the operating table end, both sides of the table, and the image intensifier (Fig. 1-D). The protective lead curtains were manufactured in-house with 0.35-mm lead aprons of L-size weighed 3.1 kg that were cut.
Radiation exposure dosimetry study (study 2) Design This study included all URS procedures for upper urinary stones that were performed between April 2014 and May 2015. A total of 123 URS procedures were 6 Page 6 of 26
included and randomly divided into a non-protective lead curtain group (n-LC group; 62 cases) and a protective lead curtain group (LC group; 61 cases) under simple randomization by using the envelope method (Supplementary Fig.1). This study was approved by the ethics committee of Kansai Medical University General Medical Center (UMIN No.; R000029628). All patients provided written informed consent. Patients in whom performing the lithotomy position or general anesthesia was impossible were excluded. The primary endpoint was a reduction in effective dose to the operator between the n-LC and LC groups. Other endpoints were the radiation exposure dose of the neck and waist outside of the lead apron, and at the chest inside of the lead apron to the operator. Arrangement of equipment The equipments were arranged in the operating room (Fig. 1-E). The patients were positioned in the lithotomy position. URS procedures for stone management were performed under general anesthesia and continuous irradiation from the X-ray tube by a single surgeon (TI) who experienced over than 200 URS procedures. The X-ray tube was under the table. The table height was set at 100 cm, which was comfortable for the surgeon. The X-ray tube height was set at 50 cm, which was easy to move a C-arm not to interfere the column and foundation of operating table. Protective lead curtains were 7 Page 7 of 26
positioned at the operating table end, both sides of the table, and the image intensifier (Fig. 1-F). The protective lead curtains were manufactured in-house with 0.35-mm lead aprons of L-size weighed 3.1 kg that were cut. Measurement of the scattered radiation exposure dose to the operator during URS was performed in the n-LC and LC groups. The operator wore protective clothes, including a 0.35-mm lead apron, a thyroid shield, and eye glasses with lead lining. Electronic pocket radiation dosimeters (PDM127; Hitachi Aloka Co., Ltd., Tokyo, Japan) were attached at the neck and at the waist outside of the lead apron and at the chest inside of the lead apron (Fig 2).
Evaluation of radiation exposure to the operator Data, such as the patient’s age, sex, body mass index side of stones, stone location, stone burden, operative time, fluoroscopic time, and stone-free rate, were collected. The size of simple stones was measured by the long axis of the stone, and the size of multiple renal stones was measured by adding the length of the longest axis of each stone. The neck and waist exposure dose outside of the lead apron (μSv), the chest exposure dose inside of the lead apron (μSv), and the effective dose (μSv) to the operator from scattered radiation were measured. Based on the 1990 recommendations of the International Commission on Radiological Protection and the Nuclear Safety 8 Page 8 of 26
Technology Center in Japan, the effective dose (ED) as calculated using the following formula: ED = 0.11 Ha + 0.89 Hb (for calculating related to external exposure when exposure is non-uniform) (Ha: 1-cm dose equivalent at the neck level on the outside of the lead apron; Hb: 1-cm dose equivalent at the chest level inside of the lead apron) 3)4)5). These parameters were compared between the n-LC and LC groups.
Statistical analysis Sample size was calculated based on our results of study 1, which indicated a reduction of 75% in exposure dose at waist level to the operator when using lead curtains. Among 82 patients, 41 per arm would be required to detect a significant difference between the n-LC and LC groups, with 80% power. We recruited about 60 patients in each group for covering the range of error and safety. All data are shown as mean ± standard deviation (SD). All collected data were analyzed using SPSS version 21 (IBM Corp., Armonk, NY, USA). Comparison between the n-LC and LC groups was performed using the Pearson chi-square test and theStudent’s t-test. A two-sided p value of < 0.05 was considered statistically significant.
RESULTS 9 Page 9 of 26
Spatial dosimetry in the operating room study (study 1) The scattered radiation dose without protective lead curtains in eight directions decreased as the distance from the X-ray tube increased (Supplementary Figure 2-A). Scattered radiation doses of 100 and 150 cm in the operator area where URS procedures were performed were 2.2 μSv/min and 1.1 μSv/min, respectively. However, scattered radiation doses of 100 and 150 cm in the operator area with protective lead curtains were 0.51 μSv/min and 0.23 μSv/min. Protective lead curtains led to a reduction of 75–80% in the scattered radiation dose compared with without lead curtains (Supplementary Figure 2-B).
Radiation exposure dosimetry study (study 2) A total of 62 patients in the n-LC group and 61 in the LC group were analyzed. Baseline patient and stone characteristics were not significantly different between the groups. Mean fluoroscopy time in the n-LC group as 116.4 ± 102.1 sec was significantly lower than that in the LC group as 118.5 ± 60.9 sec (p = 0.047, Table 1). The scattered radiation exposure doses to the operator during URS in the n-LC and LC groups are shown in Fig 3. The mean effective dose to the operator was significantly higher in the n-LC group than in the LC group (0.33 ± 0.85 vs 0.08 ± 0.08 μSv, p = 10 Page 10 of 26
0.003). The mean doses that were measured at the neck and waist outside of the lead apron, and at the chest inside of the lead apron to the operator were significantly higher in the n-LC group than in the LC group (2.22 ± 4.56 vs 0.84 ± 0.77 μSv, p = 0.008; 5.48± 12.4 vs 0.76 ± 0.89 μSv, p = 0.001; 0.10 ± 0.47 vs 0.00 ± 0.00 μSv, p = 0.001, respectively). The rate of reduction in the scattered radiation exposure dose in the LC group was 74% for the effective dose, 62.1% in the neck, and 86.1% in the waist outside of the apron, and 100% in the chest outside of the apron compared with the n-LC group.
COMMENT In the present study, protective lead curtains were effective devices for protecting the operator from scattered radiation exposure during URS. To the best of our knowledge, this study is the first to include basic spatial measurement of the scattered radiation dose using a human phantom simulating URS and the scattered radiation exposure dose to the operator during URS according to lead protective curtains. A major source of occupational radiation exposure is caused by direct radiation that is generated in the fluoroscopy field between an X-ray tube and an image intensifier. Another major source is scattered radiation that is produced from interaction of the primary radiation beam with the patient’s body and the operating table. Radiation 11 Page 11 of 26
exposure of surgeons and medical staff during procedures mostly arises because of scattered radiation 2). This scattered radiation is divided into two types: backward scattering and forward scattering. The backward scattering dose is approximately 20-fold as strong as the forward scattering dose 6). In this study, protective lead curtains that were mounted at the operating table end and at both sides of the table were used for inhibiting backward scattering. Protective lead curtains that were positioned at the image intensifier were used for inhibiting forward scattering. Consequently, the scattered radiation dose with protective lead curtains in the operator area was decreased by 75–80% compared with no protective lead curtains. Politi and colleagues studied radiation exposure of the surgeon during transradial percutaneous coronary angiography7). Radiation exposure was lower in the group with the Radpad shielding device, which is composed of a tungsten antimony lead-free material, than in the group without this device (282.8 ± 32.55 vs 367.8 ± 105.4 μSv, p<0.001). This resulted in a total dose reduction of 23% with this device7). Gilligan and associates found that radiation exposure of the surgeon using a lead Plexiglas screen shield and Radpad during transradial percutaneous coronary angiography decreased the total radiation dose by 52% (15.4 μSv per case vs 7.3 μSv per case, p<0.001) 8). In the urological field, Yang and co-workers reported that radiation exposure of the surgeon 12 Page 12 of 26
during PCNL was decreased by 71.2% at a distance of 50 cm from the image intensifier by using a radiation shield over the operative table 9). Zoller and co-workers reported that a face protection shield was effective in reducing eye lens radiation exposure during URS 10). However, there have only been a few reports on radiation exposure during URS. The occupational radiation exposure dose limit is defined as 20 mSv per year by the ICRP 11). However, Kusuba et al observed chromosomal aberrations in peripheral blood lymphocytes of Croatian hospital staff who were occupationally exposed to low levels of ionizing radiation in 2008 12). Another study showed that low levels of chronic occupational exposure to ionizing radiation causes an increase in micronuclei frequency in chromosomes, which is a biomarker of chromosomal damage, genome instability, and cancer risk, in 2010 13). Thyroid cancer was increased as a direct result of constant exposure to ionizing radiation at a low level of exposure among Australian orthopedic surgeons in 1998 14). Roguin et al reported 31 interventional physicians with brain and neck cancer who were chronically exposed to ionizing radiation during their fluoroscopic procedures in 2013 15). They found a disproportionate occurrence of tumors on the left side of the brain in 22 cases. The ICRP advocates the ALARA principle of limiting radiation exposure for optimization of protection and desire to 13 Page 13 of 26
carry out the action 16)17). In modern radiation protection practice, active personal dosimeters are absolutely essential operational tools to satisfy the ALARA principle 18). However, most urologists may have an insufficient perception of radiation protection for themselves. A previous study showed that although 84.4% of urologists who were chronically exposed to ionizing radiation wore lead aprons, only 53.9% wore a thyroid shield and 27.9% wore eye glasses with lead lining 19). Moreover, only 23.6% of urologists put on a dosimeter 19). Soylemez and co-workers reported that 75.2% of urologists with occupational radiation exposure wore lead aprons 20). However, only 46.6% wore a thyroid shield and 23.1% wore eye glasses with lead lining. Moreover, only 26.1% of urologists put on a dosimeter 20). Awareness of physicians for occupational radiation exposure in the urological field still remain low 21). Although the risks of harmful effects of occupational radiation exposure may be relatively small, they should not be ignored. Time, distance, and shielding are generally critical factors for determining the level of radiation exposure 11). Shielding is usually performed by using protective clothes for protecting oneself. The standard lead protection protocol requires the use of 0.35-mm lead aprons and thyroid shields for the operating surgeon and 0.25-mm lead aprons for other personnel 22). However, protection from scattered radiation by 14 Page 14 of 26
protective clothes is incomplete, especially to the arms, eyes, and brain. Additionally, performing procedures with these clothes under fluoroscopy causes fatigue for surgeons because of the weight of clothes and difficulty of movement, resulting in uncomfortable circumstances 23). Soylemez and co-workers reported that for urologists, wearing protective clothes is not practical and causes deterioration of the surgeon’s ergonomics 20). Therefore, our study focused on shielding of scattered radiation using protective lead curtains on the operative table. In this study, we evaluated the effect of non-uniform radiation exposure for the whole body because scattered radiation affects not only specific parts of the body, but also the whole body. Therefore, we used the ED for measurement, which was calculated using a formula that was based on the 1990 recommendations of the International Commission on Radiological Protection and the Nuclear Safety Technology Center in Japan 3)4)5)24). Although the effective dose using protective lead curtains did not result in 0 μSv in our study, the effective dose to the operator during URS was significantly decreased. In our study, the operator wore a lead apron, thyroid shield, and eye glasses with lead lining for protecting from scattered radiation exposure. Nevertheless, the operator was exposed to radiation in the inside of the lead apron without protective lead curtains. 15 Page 15 of 26
Komemushi and associates also reported that the radiation exposure dose to the operator inside of the lead apron was 0.48–0.65 μSv per procedure in interventional radiology procedures 24). Furthermore, some investigators have found that the radiation exposure dose to the operator at waist level is higher than that at the neck level at an X-ray tube under the operating table 25)26). In our study, the radiation exposure dose to the operator at waist level was 2.5 times as much as the neck level. Even if the radiation exposure dose is small, this may cause major issues of fertility for men and women. Only wearing protective clothes does not ensure complete safety. Therefore, surgeons should consider further safe-guards to protect themselves in accordance with the ALARA principle. In the present study, the radiation exposure dose to the operator inside of the lead apron with protective lead curtains was below the detectable limit. Possible limitations of this study include the following. The fluoroscopic time during URS was significantly longer in the LC group than in the n-LC group. However, despite of long fluoroscopic time in LC group, the radiation exposure dose to the operator was significantly lower. Furthermore, we did not pay attention to the setting and position of the equipment, such as using pulsed fluoroscopy, increasing collimation of the primary beam, maximizing the distance between the X-ray tube and the patient, and minimizing the distance between patients and the image intensifier 27)28). Elkoushy and 16 Page 16 of 26
co-workers reported that pulsed fluoroscopy has been associated with 60% reduction in fluoroscopy time 27). Damien and co-workers found that pulsed fluoroscopy reduced radiation dose by 64% compared with continuous fluoroscopy 29). However, a C-arm used in this study did not have a function of pulsed fluoroscopy mode and collimation. If these factors are arranged, further reduction of radiation exposure to the operator may be expected. Furthermore, the surgeon operated the image intensifier during URS procedures in this study. However, one investigator reported that radiographer delivered fluoroscopy could reduce the exposure time to ionizing radiation for some urological procedures including retrograde pyelography and semi-rigid URS, but not for flexible URS procedures. The radiographers in our institution could not help the fluoroscopy during URS procedures in operation room because of lack of workforce 30). Regardless of these limitations, using protective lead curtains during URS not only decreases the radiation exposure dose to the operator, but may also improve surgeons’ ergonomics because of the light weight of protective clothes.
CONCLUSION Protective lead curtains decrease the dose of spatially scattered radiation in the 17 Page 17 of 26
operator area. These curtains are useful devices for protecting the operator from scattered radiation, resulting in a reduction in total radiation exposure for URS surgeons.
Author Disclosure Statement No competing financial interests exist.
References 1. Linet MS, Kim KP, Miller DL, et al: Historical review of occupational exposures and cancer risks in medical radiation workers. Radiat Res 174: 793-808, 2010. 2. Hellawell GO, Mutch SJ, Thevendran G, et al: Radiation exposure and the urologist: what are the risks?. J Urol 174: 948-52, 2005. 3. ICRP Recommendations of the international commission on radiological protection. ICRP Publication 60 Ann ICRP 1991; 21 4. Komemushi A, Tanigawa N, Kariya S, et al: Radiation exposure to operators during vertebroplasty. JVIR 16: 1327-32, 2005. 5. Methods for measuring effective dose equivalent from external exposure. U. S. 18 Page 18 of 26
Nuclear Regulatory Commission Regulatory guide 8.40, 2010; 1-8 6. Lee K, Lee KM, Park MS, et al: Measurements of surgeon’s exposure to ionizing radiation dose during intraoperative use of C-arm fluoroscopy. Spine 37: 1240-4, 2012. 7. Politi L, Biondi-Zoccai G, Nocetti L, et al: Reduction of scatter radiation during transradial percutaneous coronary angiography: A randomized trial using a lead-free radiation shield. Cathet Cardiovasc Interv 79: 97-102, 2012. 8. Gilligan P, Lynch J, Eder H, et al: Assessment of clinical occupational dose reduction effect of a new interventional cardiology shield for radial access combined with a scatter reducing drape. Cathet Cardiovasc Interv 86: 935-40, 2015. 9. Yang RM, Morgan T, Bellman GC. Radiation protection during percutaneous nephrolithotomy: a new urologic surgery radiation shield. J Endourol 16: 727-31, 2002. 10. Zoller G, Figel M, Denk J, et al. Eye lens radiation exposure during ureteroscopy with and without a face protection shield: Investigations on a phantom model. Urologe A 55: 364-9, 2016. 11. Duran A, Hian SK, Miller DL, et al: Recommendations for occupational radiation protection in interventional cardiology. Cathet Cardiovasc Interv 82: 29-42, 2013. 19 Page 19 of 26
12. Kasuba V, Rozgaj R, Jazbec A: Chromosome aberrations in peripheral blood lymphocytes of Croatian hospital staff ocuppationally exposed to low level of ionizing radiation. Arh Hig Rada Toksikol 59: 251-9, 2008. 13. Eken A, Aydin A, Erdem O, et al: Cytogenetic analysis of peripheral blood lymphocytes of hospital staff occupationally exposed to low doses of ionizing radiation. Toxicol Ind Health 26: 273-80, 2010. 14. Dewey P, Incoll I: Evaluation of thyroid shield for reduction of radiation exposure to orthopaedic surgeons. Aust N.Z J Surg 68: 635-6, 1998. 15. Roguin A, Goldstein J, Bar O, et al: Brain and neck tumors among physicians performing interventional procedures. Am J Cardiol 111: 1368-72, 2013. 16. Recommendations of the Internationa Commission on Radiological Protection (Revised December, 1954): Br J Radiol. Suppl 6, 1955 17. Implications of Commission recommendations that doses be kept as low as readily achievable. A report of ICRP Committee 4, ICRP Publication 22, Pergamon press, 1973 18. Bolognese-Milsztajn T, Ginjaume M, Luszik-Bhadra M, et al: Active personal dosimeters for individual monitoring and other new development. Radiat Prot Dosimetry 112: 141-68, 2004. 20 Page 20 of 26
19. Borges CF, Reggio E, Vicentini FC, et al: How are we protecting ourselves from radiation exposure? A nationwide survey. Int Urol Nephrol 47: 271-4, 2015. 20. Soylemez H, Altunoluk B, Bozkurt Y, et al: Radiation exposure-urologists take it seriously in turkey? J Urol 187: 1301-5, 2012. 21. Adem T, Alparslan A, Nimet A, et al: Are the urology operating room personnel aware about the ionizing radiation ? Int Braz J Urol 41: 982-9, 2015. 22. Medical and Dental Guidance Notes: A Good Practice Guide on all Aspects of Ionising Radiation Protection in the Clinical Environment. York: Institute of Physics and Engineering in Medicine, 2002 23. Dehmer GJ: Occupational hazards for interventional cardiologists. Catheter Cardiovasc Interv 68: 974-6, 2006. 24. Komemushi A, Suzuki S, Sano A: Radiation dose of nurse during IR procedures: a controlled trial evaluating operator alerts before nursing tasks. J Vasc Interv Radiol 25: 1195-9, 2014. 25. Ahn Y, Kim CH, Lee JH, et al: Radiation exposure to the surgeon during percutaneous endoscopic lumber discectomy: a prospective study. Spine (Phila Pa 1976) 38: 617-25, 2013. 26. Kim KP, Miller DL, Balter S, et al: Occupational radiation doses to operators 21 Page 21 of 26
performing cardiac catheterization procedures. Health Phys 94: 211-27, 2008. 27. Elkoushy MA, Shahrour W, Andonian A: Pulsed fluoroscopy in ureteroscopy and percutaneous nephrolithotomy. Urology 79: 1230-5, 2012. 28. Horsburgh BA, Huggins M: A study of occupational radiation dosimetry during fluoroscopically guided simulated urological surgery in the lithotomy position. J Endourol 30: 1312-20, 2016. 29. Damine LS, Jonathan PH, Gideon DR et al. Radiation exposure during continuous and pulsed fluoroscopy. J Endourol 27: 384-8, 2013. 30. Martin J, Hennessey DB, Young M, et al. Radiographer delivered fluoroscopy reduces radiation exposure during endoscopic urological procedures. Ulster Med J 2016; 85 :8-12.
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Figure 1: Setting of measuring equipment and spatial distribution of the radiation dose in the operating room. The arrows indicate (A) the anthropomorphic phantom, (B) the scattered ionization chamber, and (C) protective lead curtains. (D) Equipment layout and range of measurement of spatially scattered radiation. Dot range and circles indicate protective lead curtains on the operating table and the image intensifier. (E) Equipment layout during URS. Dot range and circles indicate protective lead curtains on the operating table and image intensifier during URS. (F) Protective lead curtains and patients in the lithotomy position during URS.
Figure 2: Measurement methods of the radiation exposure dose to the operator. (A) Wearing pocket dosimeters (PDM127), (B) at the neck and (C) at the waist outside of the lead apron, and (D) at the chest inside of the lead apron.
Figure 3: Radiation exposure doses to the operator between the n-LC group and LC group during URS.
23 Page 23 of 26
Supplementary Figure 1: Consort chart.
Supplementary Figure 2: (A) Spatial distribution of the scattered radiation dose without protective lead curtains. (B) Spatial distribution of the scattered radiation dose with protective lead curtains.
24 Page 24 of 26
Table 1: Patient and stone characteristics, and surgical outcome according to protective lead curtains n-LC group
LC group
n = 62
n = 61
Age, years
62.9 ± 14.3
62.1 ± 13.0
Sex, n (%)
M: 33 (53.2) F: 29 (46.7)
M: 37 (60.6) F: 24 (39.3) 0.424
23.5 ± 4.4
23.9 ± 3.4
0.474
R: 28 (45.1) L: 29 (46.7)
R: 26 (42.6) L: 29 (47.5)
0.422
BMI, kg/m
2
Stone side, n (%)
p value* 0.498
B: 6 (9.8) B: 4 (6.4) Stone location, n (%)
39 (62.9)
30 (49.1)
11 (17.7)
20 (32.7)
proximal ureter
5 (8.0)
4 (6.5)
middle ureter
7 (11.2)
7 (11.4)
Mean stone burden, mm
17.1 ± 9.4
17.5 ± 8.3
0.475
Mean operative time, min
74.9 ± 40.4
65.1 ± 30.9
0.18
Mean fluoroscopic time, s
116.4 ± 102.1
118.5 ± 60.9
0.047
Stone-free rate, n (%)
59 (95.1)
58 (95.0)
0.984
Complication, n (%)
0 (0)
1 (1.6)
0.311
kidney
0.421
distal ureter
Data are presented as mean ± standard deviation or n (%).
25 Page 25 of 26
M=male, F=female, BMI = body mass index, R = right, L = left, B = bilateral. *Pearson chi-square test, Student’s t-test. • Stone-free was defined as residual stones <1 mm in diameter.
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