LT-200 White Paper Protective Eyewear Rev. 0

Ionizing Radiation Safety Concernsand the Benefits ofRadiation Protective EyewearRisk of Biological Injury to the Eyes ofPhysician and Non-Physician Professionalsin the Practice of Cardiology & RelatedFluoroscopic Procedures Minimizing Risk. Every Procedure. Every Time.™

Table of ContentsRadiation Cataracts [Lens Opacity] 1Radiation Effects Research Foundation, 2007Interventional Radiology Carries Occupational Risk for Cataracts 2RSNA News, June 2004Radiation Protection in Interventional Radiology 2Interventional Radiology, Vol. 1, Second EditionPotential Biological Effects Following High X-Ray Dose Interventional Procedures 3Journal of Vascular and Interventional Radiology, January-February 1994Radiation Exposure During Radiofrequency Catheter Ablation of Accessory Atrioventricular 4ConnectionsCirculation, Vol. 84, No.6, December 1991Surface Shield: Device to Reduce Personnel Radiation Exposure 4Radiology, Vol. 159, No. 3, June 1986Radiation Exposure in Endovascular Surgery of the Head and Neck 4AJNR, November 1994X-Radiation 4The Art and Science of Medical Radiography, Seventh EditionImplementation of the Principle of as Low as Reasonably Achievable (ALARA) for Medical andDental PersonnelNCRP Report No. 107, December 1990 5ACC EXPERT CONSENSUS DOCUMENT: Radiation Safety in the Practice of Cardiology 5Limacher et al., JACC Vol. 31, No. 4, 1998: 892-913Does the Endovascular Repair of Aortoiliac Aneurysms Pose a Radiation Safety Hazard to 6Vascular Surgeons?L E. Lipstiz et. Al., Journal of Vascular Surgery 2000; 32:704-10.

www.epimed.comRadiation Cataracts [Lens radiation cataracts advance to severe visual impairment,Opacity] although we have documented in a recent study about a 20- 30% excess at 1 Gy of cataracts that prompted cataract surgery.Radiation Effects Research Foundation, 2007 A low-dose threshold may exist below which radiation cataract Lens Retina does not arise, although our recent analyses suggest that there may not be a threshold, or if one exists, it is somewhere in the Normal Lens Lens with Cataract range of 0 to 0.8 Gy. The excess cataracts seen are of the types generally associated with radiation: posterior subcapsular andCataract - an opacity of the crystalline lens of the eye or its cortical cataracts. Figure 1 shows the relation between radiationcapsule. dose and cortical opacity of lens.Radiation cataract - a cataract that is caused by excessiveexposure of the eye to x-rays or other types of radiation that Figure 2 describes how lens opacity is caused by radiation.cause a change in the protein molecules of the lens. There is a transparent layer of epithelial cells on the interior frontal side of the capsule that covers the lens. This layer -Mosby’s Medical Dictionary, 8th edition. © 2009, Elsevier. maintains the function of the lens by slowly growing toward the center, achieved through cell division at the periphery (called theRadiation cataract causes partial opacity or cloudiness in the equator) of the lens.crystalline lens and results from damaged cells covering theposterior surface of the lens. Symptoms can appear as early Because radiation is especially harmful to dividing cells, exposedas one or two years following high-dose exposure and many cells at the equator are most prone to damage. For unknownyears after exposure to lower doses. It is unclear how frequently reasons, damaged cells move toward the rear of the lens before converging on the center. Such cells prevent light from traveling Figure 1. Cortical Opacity Of Lens And Radiation Dose straight forward, resulting in opacity. http://www.rerf.or.jp/radefx/early_e/cataract.html (2007) ionizing radiation (front of eye) ionizing radiation 6 OR/Sv = 1.29 (95%Cl:1.12, 1.49) anterior pole 5 equator 4 epithelium (right) 3 2 cortex 1 (left) nucleus 0Odds Ratio migration of 024 pseudoepithelial cells Weighted eye dose (Gy) posterior pole lenticular opacities (back of eye) Figure 2. Lens opacity at the posterior subcapsular region caused by radiation Effects of A-bomb Radiation on the Human Body, ed by HICARE in 1991. (Courtesy of Bunkodo Co, Ltd., Tokyo.) 1

www.epimed.comInterventional Radiology Carries Albert Einstein College of Medicine. “Interventional radiologistsOccupational Risk for Cataracts need 20/20 vision in both eyes to have excellent stereopsis and to perform the delicate procedures demanded in their occupation.”RSNA News, June 2004 The ionizing radiation associated with fluoroscopy in interventionalInterventional Radiologists are at high risk of radiation-induced and diagnostic imaging procedures can have damaging biologicaleye injury and should consider eye protection to avoid posterior effects on many types of body tissue. Sometimes these effectssubcapsular (PSC) cataract formation, according to research take years to manifest themselves, in the form of conditions thatreleased at the Society of can lead to impaired vision and even blindness. This delayedInterventional Radiology (SIR)annual meeting in March. manifestation makes it difficult to recognize the harmful effects of radiation until the damage hasThe researchers found that the I’VE SEEN EVIDENCE OF PSC already been done.frequency and severity of PSC DAMAGE IN PRACTICING Dosimetry studies have provencataracts increased with age INTERVENTIONAL RADIOLOGISTS that X-ray Protective Glassesand years in practice. can effectively eliminate 90% of IN THEIR EARLY 30S. the scattered radiation to the eye.Dr. Ziv J. Haskal, M.D. is urging Ziv J. Haskal, M.D.interventional radiologists tomore seriously consider wearinghigh-quality radiation eye Radiationprotection, and he warns themagainst being too cavalier about Protection inradiation risk… Interventional RadiologyThe researchers found that nearly half of the interventional Interventional Radiology, Vol. 1, Second Editionradiologists screened had signs of radiation-related lenschanges. “This study combined with other research shows that “Interventional radiology procedures can require substantialpeople are developing cataracts at much lower radiation doses amounts of ionizing radiation and therefore necessitatethan permissible limits allow,” says Basil V. Worgul, Ph.D., a particularly close attention to radiation protection…”professor of radiation biology in ophthalmology and radiologyat Columbia University College of Physicians and Surgeons in Because cinefluorography (cine) is an extension of fluoroscopy,New York City. all of the previous radiation protection considerations apply;The Researchers found that nearly half of the interventional however, radiation exposure is significantly higher for the patientradiologists screened had signs of radiation-related lens changes. as well as the staff…”“One of the most important findings was that the changes The scattered radiation levels shown in Figure 1.4 were obtainedobserved were found in interventional radiologists in their mid- with skin entrance exposure of 2.8 R/min; to depict the cine40s,” says Anna Junk, M.D., lead author and ophthalmologist at scattered radiation exposure, the values in the figure should be multiplied by a factor of seven to 32!Posterior Subscapular Cataract A retroillumination photo A radiation-induced showing the opacity in the cataract in its typical backside of the lens. This PSC manifestation. The cataract causes glare and centrally-placed black poor vision in bright light shadow at the back of condiditons as well as the lens is the cataract. poorer reading vision. Photo courtesy of Basil V. Photo courtesy of AgingEyes Times Worgul, Ph.D. 2

www.epimed.com 25-50 mR/hr 50-100 100-200 200-300 >300 4 3 2 1 0 Scale (ft)Figure 1.4: Maximum Number of Fluoroscopic Procedures “With the expanded and sometimes prolonged uses ofin a 3-Month Period without exceeding Eye Exposure of 1.25 fluoroscopy and Fluorography, we considered it important toR/Quarter review the potential for stochastic and deterministic effects that could occur from very high absorbed doses.” Radiation Exposure at Eye Level (mR/hr) Chronic Irradiation of Physicians’ Hands 10 25 50 100 200 300 “Late determination effects to skin of the hands are principal radiation concern of radiologists and are more important thanFluoroscopic Time 0.10 1250 500 250 125 62 41 the risk of skin cancer.” per Procedure (hr) 0.25 500 200 100 50 25 16 Skin Cancer “Radiation-induced skin cancer is a concern for both the patient 0.50 250 100 50 25 12 8 who receives a high dose in one session and the physician who accumulates a high dose to the hand over an extended period 0.75 166 67 33 16 8 5 of time. Skin cancer can be induced from longterm accumulated doses that do not cause acute erythema or epilation.” 1.00 125 50 25 12 6 4 Cataracts 1.50 83 33 16 8 4 2 “Radiation-induced cataract is a deterministic effect. The minimum latent period for the detection of radiation-induced 2.00 62 25 12 6 3 2 cataracts is approximately one year, and they initially begin in the posterior pole of the lens. Younger individuals appear toPotential Biological Effects develop cataracts earlier with more rapid progression…LeadedFollowing High X-Ray Dose protective lenses with side shields may help or may even beInterventional Procedures necessary, in this regard.”Journal of Vascular and Interventional Reducing Personnel ExposureRadiology, January-February 1994 Minimizing doses to patients is usually and effective way to help keep exposures to personnel acceptably low, but it is not“Absorbed doses from ionizing radiation administered during sufficient. Professional radiation safety practices of monitoringsome fluoroscopically and fluorographically guided interventional doses, shielding personnel, managing radiation delivery, andprocedures, such as electophysiologic ablations, transjugular maintaining quality improvement programs are also essential.”intrahepatic porosystemic shunt (TIPS) procedures, andembolization of aneurysms and arteriovenous malformation, areamong the largest from medical applications other than thosefrom radiation oncology.” 3

www.epimed.comRadiation Exposure During X-RadiationRadiofrequency Catheter Ablationof Accessory Atrioventricular The Art and Science of Medical Radiography,Connections Seventh EditionCirculation, Vol. 84, No.6, December 1991 “The rem is the ‘radiation equivalent man’ and quantifies radiation dose for human beings. The rem takes into accountOne of the risks of this procedure is radiation exposure during the biological effectiveness of different types of radiation. Thethe fluoroscopic imaging necessary to guide catheter ablation rem finds its major application in recording doses from radiationand to estimate the resultant somatic and genetic risks. monitoring devices…“A potential source of risk to the physician performing the With the use of higher kVp, the number of Compton interactions willprocedure is the radiation exposure from fluoroscopic imaging increase. This increases personnel exposure for those in the roomrequired to guide the catheter manipulation.” during the exposure. This primarily occurs during fluoroscopy or mobile radiography. One must remember that a photon scatteredFurther reduction to the radiation exposure received by the as much as 90 degrees retains most of its energy. This indicatesphysician can be accomplished by wearing leaded glasses.” the need for good radiation protection techniques…Surface Shield: Device to Reduce Glasses with lead-impregnated lenses can significantly reducePersonnel Radiation Exposure the dose to the eyes…Radiology, Vol. 159, No. 3, June 1986 In an effort to minimize occupational injury as a result of occupational exposure, the maximum permissible dose (MPD)“There has been increasing concern regarding has been established for various parts of the body based onexposure of radiology personnel to scatter radiation during radiosensitivity. The whole body MPD is five rem annually.interventional procedures… Other MPDs are as follows:Absolute radiation levels remain higher during obliquefluoroscopy results in higher k Vp and/or mA levels, which Sample Maximum Permissible Dosesincrease tube output and, therefore, scatter radiation levels…Oblique fluoroscopy results in higher k Vp and/or mA levels, Combined whole body 5 rem in any one yearwhich increase tube output and, therefore, scatter radiation levels.” occupational exposureRadiation Exposure in Lens of the eye 15 rem in any one yearEndovascular Surgery of theHead and Neck All others (e.g. red 50 rem in any one year bone marrow, breasts,AJNR, November 1994 lungs, gonads, skin, and extremities)“Conclusions: The total doses at the operator’s eyes and lefthand during the course of a year may exceed the dose limits Human fetus during 0.5 rem in gestationalrecommended by the International Commission of Radiological pregnancyProtection. Operators should wear not only body protectors, butalso thyroid protectors and lead glass spectacles. Since radiation has cumulative effect, a cumulative MPD has also been established. The cumulative MPD has historically been based on age and the whole body MPD. The historic MPD assumed no occupational exposure occurred before the age of 18 and was expressed: 5(N-18) + 135 rem Therefore, the cumulative MPD for a 45 year-old technologist is: 4(45-18) + 135 rem In 1987, the National Council on Radiation Protection changed the cumulative MPD recommendations to one rem times the age in years (NCRP Report No. 91). The new cumulative MPD recommendation is expressed as: 1 x N = MPD (where N=age) 4

www.epimed.comTherefore the cumulative MPS for a 45 year-old technologist Does the Endovascular Repairusing the recommendation is: of Aortoiliac Aneurysms Pose a Radiation Safety Hazard to1 x 45 = 45 rem Vascular Surgeons?Obviously, the new recommendations result in a significantly L E. Lipstiz et. Al., Journal of Vascular Surgerylower cumulative MPD than was recommended for the previous 2000; 32:704-10.method of calculating the cumulative MPD. Radiation safety issues are significantly underrepresented in theImplementation of the Principle of vascular surgery literature compared with that of other specialties.as Low as Reasonably Achievable(ALARA) for Medical and Dental A thyroid collar and “protective” glasses are essential. A significantPersonnel amount of the ocular exposure, up to 21%, is the result of scatter from the operator’s head, which suggests that wraparoundNCRP Report No. 107, December 1990 configurations are necessary to provide adequate protection.“The use of fluoroscopy for diagnostic imaging represents the “However, it was interesting to note that the calculated radiationlargest source of occupational exposure in medicine. Some exposure to the eyes and to the areas external to the lead shieldsadditional imaging procedures such as cardiac catheterization were not that insignificant. I did some calculations and yourconstitute a potential source of high occupational exposures… average millisievert radiation dose to the eye was 5 per year, and you have to remember that we’re going to be practicing forCardiac catheterization can result in elevated personnel approximately 20 to 30 years so if you multiply that then youmonitoring results. Like other vascular procedures, fluoroscopic get over 100 to 120 over your career plus you have the ambienttimes are long, personnel are in close proximity to the patent, daily exposure from the environment, the sun, the cosmic rays,and scatter shielding is difficult… etc, which is another 3 to 5 per year so that during your career lifetime, you can easily get over 200 mSv and that is certainlyThe use of cinefluorography during cardiac catheterization enough to cause cataracts and other eye disorders. Rememberresults in higher personnel exposure… that the radiation effects are cumulative and they are permanent as Dr Lipsitz pointed out.”ACC EXPERT CONSENSUSDOCUMENT: Radiation Safety inthe Practice of CardiologyLimacher et al., JACC Vol. 31, No. 4, 1998:892-913Cataract formation is considered a deterministic effect of radiationexposure. Appropriate eye protection is warranted [and] leadedeyeglasses may reduce the risk of future cataract development.“The use of lead eyeglasses [eyewear] decreases radiation exposureto the lens compared to measurements outside the glasses.” 5

13958 Diplomat Dr. phone: 800.866.3342 or 518.725.0209 email: [email protected] Dallas, TX 75234 fax: 518.725.0207 web: www.epimed.com LT-200 Rev. 0