Today we’ll be going over some pointers for techniques used by x-ray operators. There are a multitude of different settings and uses for an x-ray machine. We’ll teach you the basics of these settings and how they work. so you can feel comfortable when utilizing them. Many technique charts exist showing you the general recommended settings. Ours is right HERE, take a look if you’d like. We’d like to give a more broad understanding of what these settings mean.
We are also pleased to provide you with an official technique chart that will show you how to set your machine for each anatomical part of a subject. This article is for the purpose of blanket understanding to be used in conjunction with the technique chart.
Milliampere-Seconds (mAs)
Milliamprere-seconds (mAs) is the measure of radiation delivered (milliamperage) over a set period of time (seconds), expressed in mAs. This will directly affect how much radiation is received and how 'dense' the image comes out.
As tube current increases (mA), the electron production increases. This means that x-rays will be emitted at a higher frequency, thereby increasing their total quantity, this makes more general radiation which will mean more photons reaching the detector, so the apparent structural density will decrease. The time factor (s) is the measure of how long a tube will take electrons to travel through as it produces voltage. This means that 's' prescribes how much mA will last.
In short, increasing the mAs increases the intensity of the radiation sent through a patient’s body, reducing the density of whichever tissue on the x-ray film
Kilo-Volt Potential (kVp)
The kilovoltage peak (kVp) is the voltage difference between the anode and cathode of an X-ray tube, or its potential. For a given level of applied voltage, kVp sets the average energy of the X-ray spectrum emitted by the tube. The kVp value of a given tube is related to its X-ray quantity, which describes how much energy it puts out at each wavelength. kVp plays a role in adjusting the amount of penetration and exposure in an acquisition.
Put simply:
Higher KV = Lower Contrast
Lower KV = Higher Contrast
