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Journal of Neuroradiology (2015) xxx, xxx—xxx
Available online at
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ORIGINAL ARTICLE
Use of a prototype radioprotection cabin in vascular neuroradiology: Dosimetry and ergonomics Joel Guersen a,∗, Kaouthar Karmouche a, Jean Baptiste Moyon a, Estelle Osmond a, Maxime Poulin a, Jean Gabrillargues a,b, Betty Jean a,b, Emmanuel Chabert a, Frédéric Dutheil a, Lucie Cassagnes a,b, Louis Boyer a,b a
Pôle d’imagerie et de radiologie interventionnelle, CHU de Clermont-Ferrand, 63003 Clermont-Ferrand, France b ISIT UMR 6284 CNRS, université d’Auvergne, Auvergne, France
KEYWORDS Radioprotection cabin; Interventional neuroradiology; Lead vest and skirt; Thermoluminescent dosimeters
∗
Summary Objectives: The aim of this work was to compare the performance of a prototype radioprotection cabin in interventional neuroradiology, and to assess its suitability for routine use. Materials and methods: The radioprotection cabin was a prototype derived from the CATHPAX AF® model. Three operators carried out 21 procedures (19 brain arteriographies and 2 embolizations) using the radioprotection cabin and not wearing the usual lead individual protection equipment (IPE), and 17 procedures (16 brain arteriographies and 1 embolization) wearing the standard lead IPE (vest, skirt, thyroid shield and goggles), and not using the radioprotection cabin. In all cases, thermoluminescent dosimeters (TLDs) were positioned at head, trunk, pelvic region, and upper and lower limbs to measure the dose equivalent for Hp (0.07) or Hp (3) that they received, attenuated by either the cabin or the lead IPE. Parallel to these dosimetric measurements, the ergonomics of the protection cabin were appraised by each radiologist after each procedure. Results and conclusion: The cabin procured an overall reduction of 74% of the dose received on the whole body with Hp (0.07) = 0.04 mSv ± 0.01 (CL = 95%) against Hp (0.07) = 0.12 mSv ± 0.04 (CL = 95%) for the IPE. Body protection with the cabin was near complete, and close to 100% for the regions not protected by the usual IPE (e.g. the head). We also showed that design weaknesses noted by the operators that hampered procedures (light reflections, reduced hand mobility, awkward access to radioscopy pedal) could be remedied by maker’s improvements to the prototype and minor changes in work habits. © 2015 Elsevier Masson SAS. All rights reserved.
Corresponding author. E-mail address: [email protected] (J. Guersen).
http://dx.doi.org/10.1016/j.neurad.2015.04.005 0150-9861/© 2015 Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Guersen J, et al. Use of a prototype radioprotection cabin in vascular neuroradiology: Dosimetry and ergonomics. J Neuroradiol (2015), http://dx.doi.org/10.1016/j.neurad.2015.04.005
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Introduction The radioprotection of workers and patients has become a priority in interventional radiology. Despite technological improvement in equipment, the exposure of operators, who are necessarily standing very close to patients during procedures, remains a concern. Indeed, effective dose received in interventional radiology is approximately 2—4 mSv/year [1]. According to the procedure and the location, the doses received by the operator wearing Individual Protection Equipment (IPE) vary for each procedure. For example, at the waist, dose ranges from < 0.1 to 32 Sv; from 48 to 1280 Sv at the hand [2]. Lead individual protection equipment (IPE) (vest, skirt, thyroid shield, goggles) is heavy (≈ 7 kg), displays poor ergonomics [3], and protects the body areas it covers with ranging efficacy. The head is not well protected. New concepts in individual or semi-individual radioprotection are now being marketed, and radioprotection cabins have come into use in cardiology (rhythmology [4]). A first evaluation of equipment of this type was carried out in 2006 in interventional cardiology [5], and showed at least comparable shielding efficacy for the protected parts, and necessarily greater efficacy for the neck and head regions, not covered by the standard IPE. We set out to study the feasibility of using a radioprotection cabin in vascular neuroradiology. In fact, three percent of population will have an intracranial aneurysm and endovascular treatment is the first line treatment for this pathology [6,7]. To this end we compared the doses received by three operators standing in a radioprotection cabin and wearing no lead IPE, and wearing standard lead IPE.
Materials and methods Radioprotection cabin The radioprotection cabin used was a prototype derived from the CATHPAX AF® model (weight 210 kg, width 84 cm, height 196 cm) with 2 mm lead equivalent shielding on its front, left side and upper surfaces, both glazed and panelled. It is designed to be covered inside and out with a disposable sterile drape kit while being used for radiological procedures. Two front openings in the leaded glass pane, one circular on the right and the other indented on the left, are provided for the operator’s hands (Fig. 1).
Figure 1 Prototype CATHPAX AF cabin. A. Undraped cabin. B. Cabin with sterile drape kit.
Figure 2 Rear protection for neuroradiologist: side and rear views. A. Mobile screen. B. Prototype cabin. C. Neuroradiologist.
Lead individual protective equipment When they did not use the radioprotection cabin, the operators wore the usual personal lead IPE provided: vest: 0.5 mm lead equivalent on front, 0.35 mm on rear; skirt: 0.5 mm lead equivalent on front, 0.35 mm on rear; thyroid shield: 0.5 mm lead equivalent; goggles: 0.75 mm lead equivalent for front lenses, 0.25 mm for side shields.
Collective protective equipment Mobile lead screen A standard mobile leaded screen (2 mm lead equivalent) was positioned behind the cabin to intercept radiation backdiffused from the wall of the procedure room behind the operator (the ‘‘shield effect’’) [8] (Fig. 2). The simultaneous use of the cabin and the mobile screen thus formed a U in which the operator stood, the open side on the operator’s right, opposite the X-ray tubes.
With both the radioprotection cabin and the lead IPE, the operators used collective means of protection: ceilingsuspended lead strip curtains (0.5 mm lead equivalent) hung between the operator and the tube, and a lower table fixed to the examination table rail (0.5 mm lead equivalent). Usually, they are present in interventional radiology rooms and allow a protection for feet and head for each operator. In our case, there was no ceiling-suspended shield.
Please cite this article in press as: Guersen J, et al. Use of a prototype radioprotection cabin in vascular neuroradiology: Dosimetry and ergonomics. J Neuroradiol (2015), http://dx.doi.org/10.1016/j.neurad.2015.04.005
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Use of a prototype radioprotection cabin in vascular neuroradiology
Dosimeters
Results
Thermoluminescent dosimeters (TLDs): The study required 24 TLDs in tablet form, and TLDs for eye lens dosimetry. These dosimeters were specifically dispensed by the IRSN Dosimetry Laboratory for use in studies of work stations. Their main characteristics were: size: diameter 3 mm; detection threshold was 10 Sv; energy range between 20 keV and 10 MeV; homogeneity of detectors: very good; deviation between batches: 0.9444 ± 0.036; deviation in the same batch: ± 1.3%; stable reading: very high between −2.7% and 2.5%; quantities measured: Hp (0.07) for TLD tablets and Hp (3) for eye lens TLDs. Measures relative uncertainty was ± 30%. It was an expanded uncertainty (95% confidence level, k = 2).
Dosimetry
Radiology procedures and set-up
3
The 21 procedures carried out by the three neuroradiologists protected by the radioprotection cabin totaled 215 minutes of radioscopy. The 17 procedures when the operators wore the standard IPE totaled 187 minutes of radioscopy. The mean DAP of the procedures in the first group with the cabin was 15,467 cGy.cm2 , and it was 13,929 cGy.cm2 for the second group with the IPE. The tablet and eye lens TLDs were processed by the IRSN Dosimetry Laboratory. The results collected in Tables 1 and 2 below show an overall mean reduction of 74% in the Hp (0.07) dose equivalent received by the operators when they used the radioprotection cabin, compared with the IPE. Indeed, for the whole body, we obtain Hp (0.07) = 0,04 mSv ± 0,01
The study was conducted with three neuroradiologists from 7 April to 5 June 2014, and concerned 38 procedures. The radiology system was a GE Healthcare Systems biplane angiographic X-ray system of 1999, equipped with two brightness amplifiers.
Table 1 Comparison of Hp (0.07) doses received by operators without the cabin and with IPE, and with the cabin and without IPE.
Organization of the study
Location of tablet TLDs
The 24 dosimeters were split into two sets of 12: one set was used for the procedures using the radioprotection cabin, and the other for the procedures when the standard IPE was worn. The TLDs in each set were positioned at the head, trunk and back, pelvic region, ankles and forefingers every time one of the three operators taking part in the study carried out a procedure (Fig. 3). These dosimeters were placed under the operator’s sterile gown and so measured diffused radiation attenuated by either the cabin or the lead IPE. Dosimeters were placed for the measurement of eye lens Hp (3): when the radioprotection cabin was used, the two side dosimeters measured the dose attenuated by the cabin; when the standard IPE was used, they were positioned on the inner surfaces of the side arms of the leaded goggles, and so measured the attenuation obtained by the leaded glass lenses in the goggles. For each procedure, dose area product (DAP) and radioscopy time were recorded. For each of the two sets of dosimeters, the information recorded was thus the sum of the doses generated by 21 procedures with the radioprotection cabin (19 arteriographies and 2 embolizations), and by 17 procedures with the standard IPE (16 arteriographies and 1 embolization), received by each of the three radiologists who took part. For all 38 procedures, the three neuroradiologists filled out a quality grid appraising the general ergonomics of the radioprotection cabin for the execution of the procedures (fitting the guide and probe), the mobility of the cabin and the operators’ hands, the visibility of screens through the leaded cabin pane, and the accessibility of the equipment and controls of the radiology set-up. These were scored ‘very satisfactory’, ‘moderately satisfactory’ or ‘unsatisfactory’.
Head Thyroid Right middle finger Left middle finger Thorax Abdomen Right side Left side Right ankle Left ankle Back Total
Equivalent dose Hp (0.07) in mSv
Dose variation
Without cabin with IPE
With cabin without IPE
0.14 0.09 0.06
< DT 0.02 0.07
−96% −78% +17%
0.22
0.16
−27%
0.10 0.04 0.09 0.45 0.19 0.04 0.16
< DT 0.03 0.02 0.05 0.01 0.02 < DT
−95 −25% −78% −89% −94% −50% −97% −74%
DT: detection threshold set at 10 Sv.
Table 2 Comparison of Hp (3) eye lens doses received by operators without the cabin and with goggles, and with the cabin and without goggles. Location of eye lens TLDs
Equivalent dose Hp (3) in mSv Without cabin with leaded goggles
With cabin without leaded goggles
Left eye Right eye
0.02 NR
0.01 0.01
Dose variation
−50%
NR: not recorded.
Please cite this article in press as: Guersen J, et al. Use of a prototype radioprotection cabin in vascular neuroradiology: Dosimetry and ergonomics. J Neuroradiol (2015), http://dx.doi.org/10.1016/j.neurad.2015.04.005
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Figure 3
Positions of thermoluminescent dosimeters.
(CL = 95%) with the cabin, against Hp (0,07) = 0,12 mSv ± 0,04 (CL = 95%) for the IPE. The eye lens dose received (Hp (3)) was halved for the left eye, the more highly exposed one, being closer to the radiation source; the dose for the thyroid was divided by four, and doses for the thorax and left foot were both divided by 20. The hands were not protected by either the cabin or the IPE. The dose for the right middle finger was 17% higher with the cabin.
Ergonomics Concerning the overall ergonomics of the set-up, all three neuroradiologists rated the performance of the cabin moderately satisfactory or highly satisfactory for 79% of the procedures, for all the criteria scored. More specifically (Table 3), they found using the cabin moderately satisfactory or highly satisfactory in 62% of cases for ease of execution when fitting the guide and probe, and in 85% of cases for mobility of the cabin and hands. Accessibility of equipment was scored moderately satisfactory in 75% of cases. The main difficulty that the operators encountered with the cabin was the reflections on the leaded glass front pane (scored unsatisfactory in 38% of cases), accessibility of the sterile table and radioscopy pedal (scored unsatisfactory in 24% of cases) and hand mobility (scored unsatisfactory in 14% of cases), in particular inability to cross their hands.
Discussion The random variability of the procedures and the change in work habits with the cabin probably explain the difference found between the mean DAP values for the procedures
Table 3
Results of quality grid.
Criterion
Highly satisfactory
Moderately satisfactory
Unsatisfactory
Technique Preparation Not assessed (cabin not used) of approach Fitting of 9 8 4 guide and probe 2 — Fitting of — stents and/or coils Mobility Mobility of cabin Mobility of hands
4
14
3
2
16
3
11
8
18
1
18
3
6 7
10 10
5 4
27
106
35
Vision Reflections in 2 leaded pane Quality of 2 side vision Luminosity 0 Accessibility Sterile table Radioscopy pedal and injector Total
Please cite this article in press as: Guersen J, et al. Use of a prototype radioprotection cabin in vascular neuroradiology: Dosimetry and ergonomics. J Neuroradiol (2015), http://dx.doi.org/10.1016/j.neurad.2015.04.005
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Use of a prototype radioprotection cabin in vascular neuroradiology
Figure 4 cabin.
Positioning of neuroradiologist in radioprotection
carried out with the cabin (15,467 cGy.cm2 ) and for the procedures carried out with the IPE (13,929 cGy.cm2 ). We deliberately chose mostly simple procedures (diagnostic arteriographies) in order not to expose the patients to any loss of chance. We emphasise that these results were obtained with the addition of a rear screen: the prototype development will have to integrate this rear protection. Concerning the dosimetric results, the advantage of the radioprotection cabin over the IPE was undeniable. The increase in the dose measured at the middle finger of the right hand could be explained by the position taken by the operators, who rested their right hand on the lower edge of the front indent opening, thereby often leaving it outside the cabin nearer the patient (Fig. 4). Their left hand remained more often inside the cabin and so was less exposed than with the IPE. The ergonomics of the equipment, an important factor for routine use, drew criticism, in particular for points considered troublesome during the execution of the procedures: • to address the reflections on the front leaded pane of the cabin, which blurred radioscopy screen images, some solutions were successfully tried out as the study advanced: ◦ the lighting was dimmed in the procedure room. This almost completely eliminated the reflections, but at the cost of permanently darkening the entire room, ◦ a shadowless operating lamp was later used with the fluoroscopy (the lamp was switched off while the radioscopy was activated); • a solution for the awkward access to the radioscopy pedal could be to use a Bluetooth radioscopy pedal; • lastly, for the issue of hand mobility with the cabin, one proposal was to make a larger oval opening on the left in place of the circular opening, or to make a single long indented opening right across the front pane, fitted with a sterile leaded strip flap. Such a system would allow greater mobility of the two hands, which could also be crossed. This arrangement already exists on the Cathpax CRM® model cabin marketed for cardiac implantology. The
5
procedures tested (mostly diagnostic arteriographies as well as extraction of cardiac devices) were suited to the use of such an arrangement [9]. Complex embolizations that may need long guides mean that the operator may have to leave the shelter of the cabin to handle them; • the cabin frees the operator from heavy IPE so improves comfort and avoids orthopedic health problems [10]. The cabin frees the operator from heavy IPE and so improves comfort. Although the sample was too small to draw firm conclusions, we also monitored the heart rate of the same operator performing three brain arteriographies with the cabin and three arteriographies without the cabin and with the standard IPE. The operator’s mean heart rate with the cabin for the three procedures was 77 bpm, with a relative physiological cost of 17.7%. During the three arteriographies when the operator wore the standard IPE, the operator’s mean heart rate was 86 bpm (≈ +12%), with a relative physiological cost of 26%. Although statistically non-significant, these results are in line with reduced fatigue for operators using the cabin. Results of this study rejoin comparable works realized against a group of 138 patients in 2013 [11].
Conclusion The cabin we tested indisputably reduced the doses of radiation received by the direct operators carrying out brain angiographies and embolization. The radioprotective utility of the cabin was particularly significant for the body regions not covered by the standard IPE (vest and skirt), in particular the head and neck region [12]. These weaknesses could be partly remedied by improvements to this prototype made by the supplier together with small changes to work habits.
Disclosure of interest The authors have not supplied their declaration of conflict of interest.
References [1] Dendy PP. Radiation risks in interventional radiology. Br J Radiol 2008;81:1—7. [2] Miller DL, Va˜ nó E, Bartal G, Balter S, et al. Occupation radiation protection in interventional radiology: a joint guideline of the cardiovascular and interventional radiology society of Europe and the society of interventional radiology. Cardiovasc Interv Radiol 2010;33(2):230—9. [3] Moore B, VanSonnenberg E, Casola G, Novelline RA. The relationship between back pain and lead apron use in radiologists. AJR Am J Roentgenol 1992;158. [4] Birnie D, Healey JS, Krahn AD, et al. Prevalence and risk factors for cervical and lumbar spondylosis in interventional electrophysiologists. J Cardiovasc Electrophysiol 2011;2. [5] Dragusin O, Weerasooriya R, Jaïs P, Hocini M, Ector J, Takahashi Y, et al. Evaluation of a radiation protection cabin for invasive electrophysiological procedures. Eur Heart J 2007. [6] Benaissa A, Barbe C, Pierot L. Analysis of recanalization after endovascular treatment of intracranial aneurysm (ARETA trial): presentation of a prospective multicenter study. J Neuroradiol 2015;42(2):80—5.
Please cite this article in press as: Guersen J, et al. Use of a prototype radioprotection cabin in vascular neuroradiology: Dosimetry and ergonomics. J Neuroradiol (2015), http://dx.doi.org/10.1016/j.neurad.2015.04.005
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[7] Bourciera R, Redon R, Desal H. Genetic investigations on intracranial aneurysm: update and perspectives. J Neuroradiol 2015;42(2):67—71. [8] Ploux E [Thèse] Radioprotection en cardiologie interventionnelle : intérêt d’une cabine de radioprotection pour les procédures d’extraction de matériel de stimulation/défibrillation cardiaque; 2013. [9] Ploux S, Jesel L, Eschalier R, et al. Performance of a radiation protection cabin during extraction of cardiac devices. Can J Cardiol 2014;30:1602—6.
[10] Goldstein JA, Balter S, Cowley M, Hodgson J, Klein LW. Occupational hazards of interventional cardiologists: prevalence of orthopedic health problems in contemporary practice. Catheter Cardiovasc Interv 2004;63:407—11. [11] Schernthaner C, Danmayr F, Strohmer B. Significant reduction of radiation exposure using a protection cabin for electrophysiological procedures. Med Imaging Radiol 2013;1:1. [12] Roguin A, Goldstein J, Bar O, Goldstein JA. Brain and neck tumors among physicians performing interventional procedures. Paris: PubMed-Elsevier Inc.; 2013.
Please cite this article in press as: Guersen J, et al. Use of a prototype radioprotection cabin in vascular neuroradiology: Dosimetry and ergonomics. J Neuroradiol (2015), http://dx.doi.org/10.1016/j.neurad.2015.04.005
ARTICLE IN PRESS
Journal of Neuroradiology (2015) xxx, xxx—xxx
Available online at
ScienceDirect www.sciencedirect.com
ORIGINAL ARTICLE
Use of a prototype radioprotection cabin in vascular neuroradiology: Dosimetry and ergonomics Joel Guersen a,∗, Kaouthar Karmouche a, Jean Baptiste Moyon a, Estelle Osmond a, Maxime Poulin a, Jean Gabrillargues a,b, Betty Jean a,b, Emmanuel Chabert a, Frédéric Dutheil a, Lucie Cassagnes a,b, Louis Boyer a,b a
Pôle d’imagerie et de radiologie interventionnelle, CHU de Clermont-Ferrand, 63003 Clermont-Ferrand, France b ISIT UMR 6284 CNRS, université d’Auvergne, Auvergne, France
KEYWORDS Radioprotection cabin; Interventional neuroradiology; Lead vest and skirt; Thermoluminescent dosimeters
∗
Summary Objectives: The aim of this work was to compare the performance of a prototype radioprotection cabin in interventional neuroradiology, and to assess its suitability for routine use. Materials and methods: The radioprotection cabin was a prototype derived from the CATHPAX AF® model. Three operators carried out 21 procedures (19 brain arteriographies and 2 embolizations) using the radioprotection cabin and not wearing the usual lead individual protection equipment (IPE), and 17 procedures (16 brain arteriographies and 1 embolization) wearing the standard lead IPE (vest, skirt, thyroid shield and goggles), and not using the radioprotection cabin. In all cases, thermoluminescent dosimeters (TLDs) were positioned at head, trunk, pelvic region, and upper and lower limbs to measure the dose equivalent for Hp (0.07) or Hp (3) that they received, attenuated by either the cabin or the lead IPE. Parallel to these dosimetric measurements, the ergonomics of the protection cabin were appraised by each radiologist after each procedure. Results and conclusion: The cabin procured an overall reduction of 74% of the dose received on the whole body with Hp (0.07) = 0.04 mSv ± 0.01 (CL = 95%) against Hp (0.07) = 0.12 mSv ± 0.04 (CL = 95%) for the IPE. Body protection with the cabin was near complete, and close to 100% for the regions not protected by the usual IPE (e.g. the head). We also showed that design weaknesses noted by the operators that hampered procedures (light reflections, reduced hand mobility, awkward access to radioscopy pedal) could be remedied by maker’s improvements to the prototype and minor changes in work habits. © 2015 Elsevier Masson SAS. All rights reserved.
Corresponding author. E-mail address: [email protected] (J. Guersen).
http://dx.doi.org/10.1016/j.neurad.2015.04.005 0150-9861/© 2015 Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Guersen J, et al. Use of a prototype radioprotection cabin in vascular neuroradiology: Dosimetry and ergonomics. J Neuroradiol (2015), http://dx.doi.org/10.1016/j.neurad.2015.04.005
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Introduction The radioprotection of workers and patients has become a priority in interventional radiology. Despite technological improvement in equipment, the exposure of operators, who are necessarily standing very close to patients during procedures, remains a concern. Indeed, effective dose received in interventional radiology is approximately 2—4 mSv/year [1]. According to the procedure and the location, the doses received by the operator wearing Individual Protection Equipment (IPE) vary for each procedure. For example, at the waist, dose ranges from < 0.1 to 32 Sv; from 48 to 1280 Sv at the hand [2]. Lead individual protection equipment (IPE) (vest, skirt, thyroid shield, goggles) is heavy (≈ 7 kg), displays poor ergonomics [3], and protects the body areas it covers with ranging efficacy. The head is not well protected. New concepts in individual or semi-individual radioprotection are now being marketed, and radioprotection cabins have come into use in cardiology (rhythmology [4]). A first evaluation of equipment of this type was carried out in 2006 in interventional cardiology [5], and showed at least comparable shielding efficacy for the protected parts, and necessarily greater efficacy for the neck and head regions, not covered by the standard IPE. We set out to study the feasibility of using a radioprotection cabin in vascular neuroradiology. In fact, three percent of population will have an intracranial aneurysm and endovascular treatment is the first line treatment for this pathology [6,7]. To this end we compared the doses received by three operators standing in a radioprotection cabin and wearing no lead IPE, and wearing standard lead IPE.
Materials and methods Radioprotection cabin The radioprotection cabin used was a prototype derived from the CATHPAX AF® model (weight 210 kg, width 84 cm, height 196 cm) with 2 mm lead equivalent shielding on its front, left side and upper surfaces, both glazed and panelled. It is designed to be covered inside and out with a disposable sterile drape kit while being used for radiological procedures. Two front openings in the leaded glass pane, one circular on the right and the other indented on the left, are provided for the operator’s hands (Fig. 1).
Figure 1 Prototype CATHPAX AF cabin. A. Undraped cabin. B. Cabin with sterile drape kit.
Figure 2 Rear protection for neuroradiologist: side and rear views. A. Mobile screen. B. Prototype cabin. C. Neuroradiologist.
Lead individual protective equipment When they did not use the radioprotection cabin, the operators wore the usual personal lead IPE provided: vest: 0.5 mm lead equivalent on front, 0.35 mm on rear; skirt: 0.5 mm lead equivalent on front, 0.35 mm on rear; thyroid shield: 0.5 mm lead equivalent; goggles: 0.75 mm lead equivalent for front lenses, 0.25 mm for side shields.
Collective protective equipment Mobile lead screen A standard mobile leaded screen (2 mm lead equivalent) was positioned behind the cabin to intercept radiation backdiffused from the wall of the procedure room behind the operator (the ‘‘shield effect’’) [8] (Fig. 2). The simultaneous use of the cabin and the mobile screen thus formed a U in which the operator stood, the open side on the operator’s right, opposite the X-ray tubes.
With both the radioprotection cabin and the lead IPE, the operators used collective means of protection: ceilingsuspended lead strip curtains (0.5 mm lead equivalent) hung between the operator and the tube, and a lower table fixed to the examination table rail (0.5 mm lead equivalent). Usually, they are present in interventional radiology rooms and allow a protection for feet and head for each operator. In our case, there was no ceiling-suspended shield.
Please cite this article in press as: Guersen J, et al. Use of a prototype radioprotection cabin in vascular neuroradiology: Dosimetry and ergonomics. J Neuroradiol (2015), http://dx.doi.org/10.1016/j.neurad.2015.04.005
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Use of a prototype radioprotection cabin in vascular neuroradiology
Dosimeters
Results
Thermoluminescent dosimeters (TLDs): The study required 24 TLDs in tablet form, and TLDs for eye lens dosimetry. These dosimeters were specifically dispensed by the IRSN Dosimetry Laboratory for use in studies of work stations. Their main characteristics were: size: diameter 3 mm; detection threshold was 10 Sv; energy range between 20 keV and 10 MeV; homogeneity of detectors: very good; deviation between batches: 0.9444 ± 0.036; deviation in the same batch: ± 1.3%; stable reading: very high between −2.7% and 2.5%; quantities measured: Hp (0.07) for TLD tablets and Hp (3) for eye lens TLDs. Measures relative uncertainty was ± 30%. It was an expanded uncertainty (95% confidence level, k = 2).
Dosimetry
Radiology procedures and set-up
3
The 21 procedures carried out by the three neuroradiologists protected by the radioprotection cabin totaled 215 minutes of radioscopy. The 17 procedures when the operators wore the standard IPE totaled 187 minutes of radioscopy. The mean DAP of the procedures in the first group with the cabin was 15,467 cGy.cm2 , and it was 13,929 cGy.cm2 for the second group with the IPE. The tablet and eye lens TLDs were processed by the IRSN Dosimetry Laboratory. The results collected in Tables 1 and 2 below show an overall mean reduction of 74% in the Hp (0.07) dose equivalent received by the operators when they used the radioprotection cabin, compared with the IPE. Indeed, for the whole body, we obtain Hp (0.07) = 0,04 mSv ± 0,01
The study was conducted with three neuroradiologists from 7 April to 5 June 2014, and concerned 38 procedures. The radiology system was a GE Healthcare Systems biplane angiographic X-ray system of 1999, equipped with two brightness amplifiers.
Table 1 Comparison of Hp (0.07) doses received by operators without the cabin and with IPE, and with the cabin and without IPE.
Organization of the study
Location of tablet TLDs
The 24 dosimeters were split into two sets of 12: one set was used for the procedures using the radioprotection cabin, and the other for the procedures when the standard IPE was worn. The TLDs in each set were positioned at the head, trunk and back, pelvic region, ankles and forefingers every time one of the three operators taking part in the study carried out a procedure (Fig. 3). These dosimeters were placed under the operator’s sterile gown and so measured diffused radiation attenuated by either the cabin or the lead IPE. Dosimeters were placed for the measurement of eye lens Hp (3): when the radioprotection cabin was used, the two side dosimeters measured the dose attenuated by the cabin; when the standard IPE was used, they were positioned on the inner surfaces of the side arms of the leaded goggles, and so measured the attenuation obtained by the leaded glass lenses in the goggles. For each procedure, dose area product (DAP) and radioscopy time were recorded. For each of the two sets of dosimeters, the information recorded was thus the sum of the doses generated by 21 procedures with the radioprotection cabin (19 arteriographies and 2 embolizations), and by 17 procedures with the standard IPE (16 arteriographies and 1 embolization), received by each of the three radiologists who took part. For all 38 procedures, the three neuroradiologists filled out a quality grid appraising the general ergonomics of the radioprotection cabin for the execution of the procedures (fitting the guide and probe), the mobility of the cabin and the operators’ hands, the visibility of screens through the leaded cabin pane, and the accessibility of the equipment and controls of the radiology set-up. These were scored ‘very satisfactory’, ‘moderately satisfactory’ or ‘unsatisfactory’.
Head Thyroid Right middle finger Left middle finger Thorax Abdomen Right side Left side Right ankle Left ankle Back Total
Equivalent dose Hp (0.07) in mSv
Dose variation
Without cabin with IPE
With cabin without IPE
0.14 0.09 0.06
< DT 0.02 0.07
−96% −78% +17%
0.22
0.16
−27%
0.10 0.04 0.09 0.45 0.19 0.04 0.16
< DT 0.03 0.02 0.05 0.01 0.02 < DT
−95 −25% −78% −89% −94% −50% −97% −74%
DT: detection threshold set at 10 Sv.
Table 2 Comparison of Hp (3) eye lens doses received by operators without the cabin and with goggles, and with the cabin and without goggles. Location of eye lens TLDs
Equivalent dose Hp (3) in mSv Without cabin with leaded goggles
With cabin without leaded goggles
Left eye Right eye
0.02 NR
0.01 0.01
Dose variation
−50%
NR: not recorded.
Please cite this article in press as: Guersen J, et al. Use of a prototype radioprotection cabin in vascular neuroradiology: Dosimetry and ergonomics. J Neuroradiol (2015), http://dx.doi.org/10.1016/j.neurad.2015.04.005
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Figure 3
Positions of thermoluminescent dosimeters.
(CL = 95%) with the cabin, against Hp (0,07) = 0,12 mSv ± 0,04 (CL = 95%) for the IPE. The eye lens dose received (Hp (3)) was halved for the left eye, the more highly exposed one, being closer to the radiation source; the dose for the thyroid was divided by four, and doses for the thorax and left foot were both divided by 20. The hands were not protected by either the cabin or the IPE. The dose for the right middle finger was 17% higher with the cabin.
Ergonomics Concerning the overall ergonomics of the set-up, all three neuroradiologists rated the performance of the cabin moderately satisfactory or highly satisfactory for 79% of the procedures, for all the criteria scored. More specifically (Table 3), they found using the cabin moderately satisfactory or highly satisfactory in 62% of cases for ease of execution when fitting the guide and probe, and in 85% of cases for mobility of the cabin and hands. Accessibility of equipment was scored moderately satisfactory in 75% of cases. The main difficulty that the operators encountered with the cabin was the reflections on the leaded glass front pane (scored unsatisfactory in 38% of cases), accessibility of the sterile table and radioscopy pedal (scored unsatisfactory in 24% of cases) and hand mobility (scored unsatisfactory in 14% of cases), in particular inability to cross their hands.
Discussion The random variability of the procedures and the change in work habits with the cabin probably explain the difference found between the mean DAP values for the procedures
Table 3
Results of quality grid.
Criterion
Highly satisfactory
Moderately satisfactory
Unsatisfactory
Technique Preparation Not assessed (cabin not used) of approach Fitting of 9 8 4 guide and probe 2 — Fitting of — stents and/or coils Mobility Mobility of cabin Mobility of hands
4
14
3
2
16
3
11
8
18
1
18
3
6 7
10 10
5 4
27
106
35
Vision Reflections in 2 leaded pane Quality of 2 side vision Luminosity 0 Accessibility Sterile table Radioscopy pedal and injector Total
Please cite this article in press as: Guersen J, et al. Use of a prototype radioprotection cabin in vascular neuroradiology: Dosimetry and ergonomics. J Neuroradiol (2015), http://dx.doi.org/10.1016/j.neurad.2015.04.005
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Use of a prototype radioprotection cabin in vascular neuroradiology
Figure 4 cabin.
Positioning of neuroradiologist in radioprotection
carried out with the cabin (15,467 cGy.cm2 ) and for the procedures carried out with the IPE (13,929 cGy.cm2 ). We deliberately chose mostly simple procedures (diagnostic arteriographies) in order not to expose the patients to any loss of chance. We emphasise that these results were obtained with the addition of a rear screen: the prototype development will have to integrate this rear protection. Concerning the dosimetric results, the advantage of the radioprotection cabin over the IPE was undeniable. The increase in the dose measured at the middle finger of the right hand could be explained by the position taken by the operators, who rested their right hand on the lower edge of the front indent opening, thereby often leaving it outside the cabin nearer the patient (Fig. 4). Their left hand remained more often inside the cabin and so was less exposed than with the IPE. The ergonomics of the equipment, an important factor for routine use, drew criticism, in particular for points considered troublesome during the execution of the procedures: • to address the reflections on the front leaded pane of the cabin, which blurred radioscopy screen images, some solutions were successfully tried out as the study advanced: ◦ the lighting was dimmed in the procedure room. This almost completely eliminated the reflections, but at the cost of permanently darkening the entire room, ◦ a shadowless operating lamp was later used with the fluoroscopy (the lamp was switched off while the radioscopy was activated); • a solution for the awkward access to the radioscopy pedal could be to use a Bluetooth radioscopy pedal; • lastly, for the issue of hand mobility with the cabin, one proposal was to make a larger oval opening on the left in place of the circular opening, or to make a single long indented opening right across the front pane, fitted with a sterile leaded strip flap. Such a system would allow greater mobility of the two hands, which could also be crossed. This arrangement already exists on the Cathpax CRM® model cabin marketed for cardiac implantology. The
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procedures tested (mostly diagnostic arteriographies as well as extraction of cardiac devices) were suited to the use of such an arrangement [9]. Complex embolizations that may need long guides mean that the operator may have to leave the shelter of the cabin to handle them; • the cabin frees the operator from heavy IPE so improves comfort and avoids orthopedic health problems [10]. The cabin frees the operator from heavy IPE and so improves comfort. Although the sample was too small to draw firm conclusions, we also monitored the heart rate of the same operator performing three brain arteriographies with the cabin and three arteriographies without the cabin and with the standard IPE. The operator’s mean heart rate with the cabin for the three procedures was 77 bpm, with a relative physiological cost of 17.7%. During the three arteriographies when the operator wore the standard IPE, the operator’s mean heart rate was 86 bpm (≈ +12%), with a relative physiological cost of 26%. Although statistically non-significant, these results are in line with reduced fatigue for operators using the cabin. Results of this study rejoin comparable works realized against a group of 138 patients in 2013 [11].
Conclusion The cabin we tested indisputably reduced the doses of radiation received by the direct operators carrying out brain angiographies and embolization. The radioprotective utility of the cabin was particularly significant for the body regions not covered by the standard IPE (vest and skirt), in particular the head and neck region [12]. These weaknesses could be partly remedied by improvements to this prototype made by the supplier together with small changes to work habits.
Disclosure of interest The authors have not supplied their declaration of conflict of interest.
References [1] Dendy PP. Radiation risks in interventional radiology. Br J Radiol 2008;81:1—7. [2] Miller DL, Va˜ nó E, Bartal G, Balter S, et al. Occupation radiation protection in interventional radiology: a joint guideline of the cardiovascular and interventional radiology society of Europe and the society of interventional radiology. Cardiovasc Interv Radiol 2010;33(2):230—9. [3] Moore B, VanSonnenberg E, Casola G, Novelline RA. The relationship between back pain and lead apron use in radiologists. AJR Am J Roentgenol 1992;158. [4] Birnie D, Healey JS, Krahn AD, et al. Prevalence and risk factors for cervical and lumbar spondylosis in interventional electrophysiologists. J Cardiovasc Electrophysiol 2011;2. [5] Dragusin O, Weerasooriya R, Jaïs P, Hocini M, Ector J, Takahashi Y, et al. Evaluation of a radiation protection cabin for invasive electrophysiological procedures. Eur Heart J 2007. [6] Benaissa A, Barbe C, Pierot L. Analysis of recanalization after endovascular treatment of intracranial aneurysm (ARETA trial): presentation of a prospective multicenter study. J Neuroradiol 2015;42(2):80—5.
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[7] Bourciera R, Redon R, Desal H. Genetic investigations on intracranial aneurysm: update and perspectives. J Neuroradiol 2015;42(2):67—71. [8] Ploux E [Thèse] Radioprotection en cardiologie interventionnelle : intérêt d’une cabine de radioprotection pour les procédures d’extraction de matériel de stimulation/défibrillation cardiaque; 2013. [9] Ploux S, Jesel L, Eschalier R, et al. Performance of a radiation protection cabin during extraction of cardiac devices. Can J Cardiol 2014;30:1602—6.
[10] Goldstein JA, Balter S, Cowley M, Hodgson J, Klein LW. Occupational hazards of interventional cardiologists: prevalence of orthopedic health problems in contemporary practice. Catheter Cardiovasc Interv 2004;63:407—11. [11] Schernthaner C, Danmayr F, Strohmer B. Significant reduction of radiation exposure using a protection cabin for electrophysiological procedures. Med Imaging Radiol 2013;1:1. [12] Roguin A, Goldstein J, Bar O, Goldstein JA. Brain and neck tumors among physicians performing interventional procedures. Paris: PubMed-Elsevier Inc.; 2013.
Please cite this article in press as: Guersen J, et al. Use of a prototype radioprotection cabin in vascular neuroradiology: Dosimetry and ergonomics. J Neuroradiol (2015), http://dx.doi.org/10.1016/j.neurad.2015.04.005
