[FWD] [FDA] Radiation-Induced Skin Injuries from Fluoroscopy

[llaufman@bcm.tmc.edu (Larry Laufman, Ed.D.)]

I'm not a health physicist or radiological engineer, but I am involved in a 
study of the health effects of radiation from the Chernobyl nuclear 
accident.  In keeping an eye open for items related to radiation and health, 
I thought the following might be of interest:

>HICNet Medical News Digest      Wed, 21 Dec 1994        Volume 07 : Issue 60
>From: mednews@stat.com (HICNet Medical News)
>To: hicnews
>Subject: [FDA] Radiation-Induced Skin Injuries from Fluoroscopy
>
>           Radiation-Induced Skin Injuries from Fluoroscopy
>
>     FDA has received a number of reports of serious radiation-
>induced skin injuries resulting from prolonged fluoroscopic imaging
>during interventional therapeutic procedures. Such procedures
>include angioplasty and radio-frequency cardiac catheter ablation,
>among others. In some of the reported injuries, the physicians
>performing the procedures appear to have been unaware that the
>radiation doses exceeded the expected threshold for injury, or were
>unaware of the intensity of the fluoroscopic beam. It is important
>to note that the onset of these injuries is usually delayed, so
>that the physician cannot discern the damage by observing the
>patient immediately after the treatment.
>     The radiation dose required to cause skin injury depends on a
>number of factors, including the type of injury, the area of skin
>exposed, the age of the patient (and other patient-specific
>characteristics), and the circumstances of the exposure-single
>exposure or fractionation. Typical threshold doses are about 3 Gy
>(300 rad) for temporary epilation, about 6 Gy (600 rad) for
>erythema, and 15 to 20 Gy (1500 to 2000 rad) for moist desquamation
>ulceration and dermal necrosis.
>The absorbed dose rate in the skin from the direct beam of a
>fluoroscopic x-ray system is typically in the range of 0.02 Gy/min.
>to 0.05 Gy/min. (2-5 rad/min.), but may be higher, depending on
>equipment mode and the size of the patient. Thus, total
>fluoroscopic exposure time exceeding about one hour can result in
>skin injury, and significantly longer exposure times can produce
>serious injuries.
>     FDA suggests that facilities performing fluoroscopically
>guided procedures observe the following principles:
>~    Establish standard operating procedures and clinical protocols
>for each specific type of procedure performed. The protocols should
>be preplanned and address all aspects of the procedure, from
>patient selection through termination criteria.
>~    Know the radiation dose rates for the specific fluoroscopic
>system and for each mode of operation used during the clinical
>protocol.
>~    Know the impact of the protocol for the procedure relative to
>the potential for radiation injury due to the cumulative radiation
>dose to irradiated areas of the skin.
>~    Modify the protocol, if necessary, to limit the cumulative
>dose to any irradiated area of the skin to avoid doses that would
>induce unacceptable adverse effects. Implement equipment features
>that aid in minimizing dose.
>~    Enlist a qualified medical physicist to assist in implementing
>these principles in such a manner so as not to adversely affect the
>clinical objectives of the procedure.
>   Physicians should know that radiation-induced injuries are not
>immediately apparent. Other than the mildest symptoms, such as
>transient erythema, the effects of the radiation may not appear
>until weeks following the exposure. Physicians performing these
>procedures may not be in direct contact with the patients following
>the procedures and may not observe the milder symptoms when they
>occur. Only when symptoms of serious injury occur do the physicians
>become aware of the magnitude of the radiation doses associated
>with the procedures. For this reason, facilities should record
>information from the procedure in the patient's medical record, to
>facilitate subsequent assessment of the radiation dose should the
>need arise.
>   Physicians and medical facilities are reminded of the obligation
>to report serious injuries associated with the use of a medical
>device to the manufacturer of the device or to FDA. The medWatch
>Program provides the means for such reporting.
>   If you have questions or need information dealing with radiation
>injuries from fluoroscopy, contact the Division of Device User
>Programs and Systems Analysis, Center for Devices and Radiological
>Health (HFZ-230), 5600 Fishers Lane, Rockville, MD 20857.
>
>

Best wishes for a happy holiday season.

Larry Laufman, Ed.D.
Baylor College of Medicine
One Baylor Plaza - SM 443
Houston, Texas 77030 USA
Email:  llaufman@bcm.tmc.edu
Tel:      (713) 798-5387
Fax:     (713) 798-3990