AEC AUTOMATIC EXPOSURE CONTROL
#التحكم التلقائي في عوامل التعرض
#Automatic exposure control
#التحكم الاتوماتيكي بكمية الأشعة
#exposure factor
#kvp
#MAS
#X-Ray
What Is Automatic Exposure Control?
Any device that measures quantity of radiation either passing through Pt or image receptor -then
Automatically terminates exposure when predetermined optimal density is reached
You give up control of exposure density to a machine
Most technologists refer to AEC as "phototiming
Purpose of AEC
To deliver consistent, reproducible exposures across a wide range of:
• Anatomical thicknesses
Types of body parts and pts.
Equipment
• Techs
Rooms
DIFFERENT TYPES OF AEC
1. Phototiming: (no computer involved)
2. Programmed Exposure: (computer controlled)
3. Anatomically Programmed Radiography (APR) (similar to Programmed Exposure but with little pictures of anatomy)
All three of 3 types of AEC units use some type of radiation detector device
- Photodiodes (photocell)
lonization chamber
And a backup timer
Upside of using AEC
- Takes less time to set up technique -speeds up exan
- Improves exposure accuracy, as long as proper positioning is used
Lowers repeat rate
Saves pt exposure
- More consistency in density
from visit to visit
tech to tech
• room to room
hospital to hospital
Important to remember!
Never pucontrast filleanatomy oveAEC cell!
Or breast implant
Or metal prosthesis Or shielding
All rooms aren't calibrated the same
Rooms change over time
Service engineer calibrates initially using phantom then must periodically recheck