Beam Quantity

The number of electrons which will pass through the cathode filament is determined by the amperage and the exposure time. Increasing the amperage or exposure time will increase the number of photons generated in the x-ray tube. Since the amperage and the exposure time directly influence the number of photons emitted, they form a common factor called the milliampere-seconds (mAs). In order to increase one of these two factors, you have to take into account that the other settings are decreased in order to maintain that same beam quantity (Figure 6).^1,2,3,4,9

Figure 6. Change of x-ray spectrum with change of exposure time and/or amperage.

Figure 6. Change of x-ray spectrum with change of exposure time and/or amperage.