Table of Contents
- 1 What is the relationship between Milliamperage and exposure time?
- 2 What is Milliamperage in radiography?
- 3 What is the 15% rule?
- 4 What is the difference between Kilovoltage and Milliamperage?
- 5 When should the 15 rule be applied?
- 6 What four factors affect the proper scale of radiographic contrast?
- 7 What’s the relationship between exposure time and MA?
- 8 How is exposure time related to patient dose?
What is the relationship between Milliamperage and exposure time?
The product of milliamperage and exposure time has a direct proportional relationship with the quantity of x-rays produced. Because the milliamperage/second (mAs) controls the number of electrons boiled off of the filament and available to produce x-rays, it is considered the primary factor controlling quantity.
What is exposure time radiography?
The exposure time. The distance between the radiation source and the film. The material of the component being radiographed. The thickness of the material that the radiation must travel through. The amount of scattered radiation reaching the film.
What is Milliamperage in radiography?
Milliampere-seconds, also more commonly known as mAs, is a measure of radiation produced (milliamperage) over a set amount of time (seconds) via an x-ray tube. It directly influences the radiographic density, when all other factors are constant.
What are the important factors to be considered in determining the exposure time?
Other important factors to consider when defining exposure are the timeframe (induction and latent periods), changes in exposure status or exposure to other therapies, and consistency and accuracy of exposure measurement.
What is the 15% rule?
The “rule of 15” is commonly used as a guideline for treatment: After checking your blood glucose level with your meter and seeing that your level is under 70 mg/dl, consume 15 grams of carbohydrate, wait about 15 minutes, then recheck your blood glucose level.
What are the 4 primary exposure factors?
The quantity and quality of the x-ray beam are controlled by four prime factors. These factors are under the direct control of the limited operator. The prime factors of exposure are milliamperage (mA), exposure time (S), kVp, and SID.
What is the difference between Kilovoltage and Milliamperage?
The milliamperage determines the density or blackness of a film. Kilovoltage brings out the contrast between hard and soft tissues. Milliamperage is the dangerous factor in x-ray radiation and should be reduced wherever feasible. The higher the kilovoltage, the greater the penetration.
What are the exposure factors?
Exposure factor (EF) is the subjective, potential percentage of loss to a specific asset if a specific threat is realized. The exposure factor is a subjective value that the person assessing risk must define. The exposure factor is represented in the impact of the risk over the asset, or percentage of asset lost.
When should the 15 rule be applied?
After the carbohydrate is eaten, the person should wait about 15 minutes for the sugar to get into their blood. If the person does not feel better within 15 minutes more carbohydrate can be consumed. Their blood sugar should be checked to make sure it has come within a safe range.
What is the 10kvp rule?
A longstanding ‘rule of thumb’ suggests that increasing kVp by 10 whilst halving the time gives similar perceptual image quality when compared to the original exposure factors.
What four factors affect the proper scale of radiographic contrast?
It is affected by the geometric factors of the exposure: size of the radiation source (focal spot size), distance from the target/source to the film and distance from the part to the film.
What happens when Kilovoltage is increased?
An increase in kVp extends and intensifies the x-ray emission spectrum, such that the maximal and average/effective energies are higher and the photon number/intensity is higher.
What’s the relationship between exposure time and MA?
Some xray machine are capable of producing as much as 1000 or 1500 mA. The relationship between mA and exposure time is simple. The product of mA and time is milliampereseconds (mAs), which is an indicator of the total quantity of radiation produced in the exposure.
How is milliamperage related to current flow rate?
Milliamperage (mA) is a measure of the current flow rate in the xray tube circuit. It determines the number of electron available to cross the tube and thus the rate at which xrays are produced. You can think of mA as an indication of the number of xray photons that will be produced per second.
Patient dose is directly proportional to exposure time. Exposure time settings may vary from a short as 1 millisecond to as long as several seconds. Some units have AECs. These automatic exposure timers terminate the exposure when a specific quantity of radiation has reached the image receptor.
How is exposure time measured in milliseconds?
Exposure time is a measure of how long the exposure will continue and is measured in units of seconds, fractions of seconds, or milliseconds. Electronic timers provide a wide range of possible settings, allowing the operator to precisely control the length of exposure.