Elsevier items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. X-Ray Emission Chapter 9

Quantity Synonyms: intensity, MAS, # of x-rays  What influences the Quantity of x-rays produced?  Filament current (mA)  Time (in seconds “S”)  Inverse Square Law Elsevier items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 2

What is mA?  The number of electrons traveling from the cathode to the anode  mA is controlled by the amount of heat or amperage put on the filament from the step down transformer (4-6 amps). Elsevier items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 3

Quality Synonyms: Energy, KVP, Penetration  What influences the Quality of x-rays produced.  Machine phase: single, 3 phase, high frequency generator.  KV selected at the console  The amount of added or inherent filtration. Elsevier items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 4

Filtration 5 RADT 3403 Radiation Protection Chapter 10

Filtration  Types of filtration:  Inherent  Added Total Filtration = inherent + added Total Filtration needs to be 2.5 mm Aluminum Equivalent (Al. Eq.) on 70 kVp or higher exposures 6 RADT 3403 Radiation Protection Chapter 10

Filtration 7

Filtration – Half Value Layer Half Value Layer (HVL) = thickness of material to reduce beam intensity (quantity) by half 8 RADT 3403 Radiation Protection Chapter 10

Determining Half Value Layer 9 RADT 3403 Radiation Protection Chapter 10

Elsevier items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 10 Factors Affecting Quality and Quantity Quantity increases with :  Increased kVp  Increased mAs  Decreased distance  Decreased filtration Quality increases with:  Increased kVp  Increased filtration