Health and Biological Effects of Radiation Elsevier items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc.

Radiation risks: Non-stochastic Commonly referred to as deterministic or somatic effects. Threshold-related symptoms worsen with dose Skin changes: erythema /hair loss/ulceration Cataracts Teratogenesis

Radiation risks: Stochastic Also known as genetic Non-threshold, increasing probability with dose Severity of condition independent of dose Genetic mutation Genomic instability Cancer induction

Genetic Effects of Radiation Exposure Linear, nonthreshold response All mutations are harmful Exclusively naturally occurring mutations Dependent on fractionation and protraction Females less radiosensitive than males Most mutations are recessive

It is possible to inflict damage during radiology procedures! A subtle and disturbing aspect of radiation damage can be the delay in its manifestation. One cannot automatically assume that when such damage occurs long after a fluoroscopy study, that it's cause will be associated with the study. It is highly probable that there are fluoroscopists who have inadvertently caused radiation burns to a patient and are not aware of injury inflicted. 16-21 weeks post- fluoroscopic procedure 18-21 months post procedure Close-up Courtesy FDA Web Site: http://www.fda.gov/cdrh/rsnaii.html

Patient Dose Factors / Considerations Fluoroscopic exposure time or # of radiographic exposures Beam parameters Intensity Penetration Distance from x-ray tube Beam size Sensitivity of exposed organs damage threshold It is the responsibility of the fluoroscopist to minimize fluoroscopic exposure within clinical limits as well as to understand the associated risks to the patient Fortunately many of the issues just discussed which reduce operator exposure also reduce patient exposure. Although some actions reduce both patient and operator exposure and improve image quality, unfortunately, some actions which reduce patient exposure also degrade the image quality. The principle source of radiation to patients is the primary beam, radiation coming directly from the x-ray tube. Exposure for a particular patient depends upon the beam's intensity, the length of time the beam is on, the distance of the patient from the x-ray tube, the collimation of the x-ray beam. Different organs exhibit different sensitivities to radiation. Damage thresholds to various organs can be exceeded. In fluoroscopy skin is often the critical organ in terms of the amount of radiation received and the threshold for damage.

Risk Estimates Relative risk Excess risk Absolute risk Observed cases/Expected cases Excess risk Absolute risk # Cases/106 persons/rad/yr

Radiation Induced Leukemia Latent period = 4 to 7 years At-risk period = 20 years

Radiation Induced Cancers Observed in Irradiated Populations Thyroid cancer Thymus irradiation Rongelap Atoll nuclear test Bone cancer Radium watch dial painters Radium salt treatment Skin cancer Orthovoltage radiation therapy Breast cancer Tb treatment A-bomb survivors Lung cancer Uranium miners Liver and spleen cancer Thorotrast

Effects of 200 rad in Utero

Expected Days of Life Lost Risky Condition Expected Days of Life Lost Being male rather than female 2800 Heart disease 2100 Being unmarried 2000 One pack of cigarettes a day 1600 Working as a coal miner 1100 Cancer 980 30 pounds overweight 900 Stroke 520 All accidents 435 Service in Vietnam 400 Motor vehicle accidents 200 Average occupational accidents 74 Speed limit increase from 55 to 65 mph 40 Radiation worker 12 Airplane crashes 1

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