Introduction to and History of Fluoroscopy Radiation Protection Based on: Syllabus on Fluoroscopy Radiation Protection, 6th Revision California Department of Health Services Created by: Jed Miles, BSRS, RT(R), CRT-CA

Syllabus Current version is 6th revision of “Syllabus on Fluoroscopy Radiation Protection” written in 1975 Fluoroscopic systems have vastly improved during the next 3+ decades Most new fluoroscopic system installations utilize digital technology California State “Technologist Fluoroscopic Permit” examination questions are based on this revision New syllabus is being written and is in final stages of acceptance and adoption by the Radiology Health Branch of California

Historical Development of Fluoroscopy William Roentgen November 8, 1895: noticed a barium platinocyanide screen fluorescing as a result of being exposed to what he would later call x-rays Thomas Edison A few months later (1896), discovered that calcium tungstate screens produced brighter images. Credited with designing and producing the first commercially available fluoroscope

Early Fluoroscopic Imaging Early fluoroscopic imaging consisted of an x-ray tube coupled with a specialized image receptor Called a conventional fluoroscopy screen Live or dynamic images could be viewed on this screen during continuous x-ray exposure

Early Radiation Exposure While performing a fluoroscopic study, radiologists received full dose of transmitted primary beam to upper torso and face Many radiologists developed leukemia and died, thus becoming martyrs for radiologic science Once the biological hazards became apparent, the design of the fluoroscope was changed to permit viewing through an arrangement of mirrors. Later fluoro screens were attached to table

Mirrored Fluoroscopy Arrangement of mirrors shielded the primary beam because: X-ray tube mounted under (inside) the table Conventional fluoroscopic screen mounted over table and contained within lead-lined canister Series of mirrors permit viewing image without direct radiation exposure to face and upper body Primary beam contained within a lead-lined enclosure

Human Eye – Rods and Cones Visual acuity is the ability to perceive small objects Rods and cones are structures in the eye responsible for the sensation of vision Rods: Scotopic (night) vision Sensitive to low level light Essentially colorblind Cones: See fine details in objects and perceive contrast Photopic (day) vision Sensitive to high or intense light level situations Used for color vision

Human Eye and Fluoroscopy Photopic visual acuity is 10x’s greater than scotopic Requires brightness 1,000 times greater than that of a conventional fluoroscopic screen Early conventional fluoro screens produced a very dim image Dark adaptation time of 10-15 minutes was required to activate the rods Exclusive use of retinal rods to view the image constituted a threat to diagnostic accuracy

Image Intensification Tubes 1948: Major breakthrough in technology Evacuated glass image intensification tube developed as image receptor Achieved same brightness of image while using a lower dose rate Enabled video cameras and TV viewing monitors to replace mirror viewing systems Technology was crude and resulted in a loss of detail compared to mirrored viewing system Paved the way for the methods of fluoroscopic viewing in use today.

Modern Image Intensifiers Modern image intensifiers are designed to electronically amplify the brightness of an image in a range of 500 – 8,000 times

What’s Next? Please close this PowerPoint presentation, and then click Discussion 1 to continue.