Personnel Protection 

Sources of Radiation Exposure
Primary X-ray Beam
•	X-rays emitted from the x-ray tube before interaction with the patient
•	Avoid interaction with the primary beam
Secondary Radiation
•	scatter- (patient as source) patient is primary source of scatter radiation. Intensity of scatter 1M from patient is .1% 

•	Leakage-which is emitted from the x-ray tube housing in other directions than the primary beam. NCRP states that leakage must be limited to <100mR/h at a distance of 1M from the tube 
Basic Methods of Protection
•	3 cardinal rules for protection 
–	Time
–	Distance
–	Shielding 
Time
•	least amount of time for exposure 
Distance
•	longest distance possible  
–	inverse square law
–	The intensity of radiation is inversely proportional to the square of the distance from the source
Shielding
•	shield shield shield 
•	Shield all patients of child bearing age (10-55 y/o)
•	Shield yourself if operating fluoroscopy, performing portable exams, or when holding a patient
•	Wear lead gloves when hands will be in the primary beam
Protective Devices
Types
•	PRIMARY BARRIERS protect against direct exposure from primary beam example: 
–	lead walls, doors any surface that can be struck by the primary beam.  
–	Walls should have 1/16 inch lead thickness and 7 feet high

•	SECONDARY BARRIERS protect from leakage and scatter radiation (patient) example: 
–	walls above the 7 feet requires 1/32 inch lead, Control booth (primary beam must not be directed towards) 

•	PROTECTIVE APPAREL: at least .25mm lead. Considered secondary barriers  and must have proper care
Attenuation Properties
(Increased Atomic # = Increased Attenuation)
•	Fat = effective atomic # 6.3
•	Soft tissue and lung = 7.4
•	Bone = 13.8
•	Contrast Material
–	Air = 7.6
–	Iodine = 53
–	Barium = 56
–	Other
•	Concrete = 17
•	Molybdenum = 42
•	Tungsten = 74
•	Lead = 82

Minimum Lead Equivalent (NCRP #102)
•	Primary Barrier – 7ft high, 1/16 inch Pb equivalency
•	Secondary Barrier – 1/32 inch Pb equivalency
•	Glass Window – 1.5 mm Pb equivalency
•	Lead aprons - .25 mm Pb equivalency (most are .5 mm and 1.0 will protect up to 99% of the beam)
•	Lead gloves must be .25 mm Pb equivalency
•	Eyewear is not required but available
•	Protective lead curtain for fluoroscopic procedures must be .25 mm Pb equivalency
Special Considerations
Portable (Mobile) Units
•	Must have lead apron and tech should wear it during exposures 
•	Cord should be long enough to get back  6 feet
•	Stand behind the machine (NO!!) 
Protective Bucky Slot Cover
•	Used to prevent radiation at waist level. Pulls in place by moving the bucky down 
Cumulative Timer
•	Timer will go off to notify you that 5 minutes has passed 
•	Pressing the “alarm reset” button will continue time accumulation
•	Pressing the “0” or reset button will reset time and alarm
Fluoroscopy
•	Provide at least 12 inches and preferably 15 inches between source and the tabletop for mobile fluoroscopy
•	Provide at least 15 inches between source and tabletop for fixed fluoroscopy
•	Tabletop intensity of the fluoroscopic beam must not exceed 10R/min
•	Fluoro mA must not exceed 5
•	Image Intensifier must have a lead equivalent of at least 2.0 mm.
•	Beam collimations must be apparent through visualization of unexposed border on monitor
•	Total filtration must be at least 2.5 mm Al equivalent.
•	Protective curtain must be at least .25 mm Pb and be placed between the patient and fluoroscopist.
Fluoroscopy Continued
•	Highest radiation intensity for fluoro is 90 degrees from incident beam (at level of gonads of the operator)
•	Because of this, more protective devices are placed in this area (shield, bucky slot cover)
•	High incidence of radiation at head of table
•	Use of intermittent or pulsating fluoro is recommended 
Exposure Switch Guidelines
•	Deadman, let off and exposure quits