Home
Back
mAs Formula:
| From: | To: |
mAs (milliampere-seconds) is a crucial parameter in radiology that represents the product of tube current (mA) and exposure time (seconds). It directly affects the quantity of X-ray photons produced and therefore the image quality and patient dose.
The calculator uses the mAs formula:
Where:
Explanation: The mAs value determines the total radiation output, affecting both image quality (noise) and patient radiation dose.
Details: Proper mAs selection is essential for achieving diagnostic image quality while maintaining radiation doses as low as reasonably achievable (ALARA principle). mAs directly controls the quantity of radiation and affects image contrast and noise.
Tips: Enter mA value in milliamperes and exposure time in seconds. Both values must be positive numbers. The calculator will compute the mAs product.
Q1: What is the typical range of mAs values in radiography?
A: mAs values typically range from 0.5 to 100 mAs, depending on the anatomical region, patient size, and imaging equipment.
Q2: How does mAs affect image quality?
A: Higher mAs increases radiation dose but reduces image noise, while lower mAs decreases dose but increases noise. The optimal balance depends on clinical requirements.
Q3: What's the relationship between mAs and kVp?
A: mAs controls quantity of radiation, while kVp controls quality (energy) of radiation. Both parameters work together to achieve optimal image quality.
Q4: Why is mAs important for radiation safety?
A: mAs directly contributes to patient radiation dose. Proper mAs selection helps minimize unnecessary radiation exposure while maintaining diagnostic image quality.
Q5: Can mAs be automatically controlled in modern equipment?
A: Yes, most modern X-ray systems use automatic exposure control (AEC) that automatically adjusts mAs based on detected radiation to achieve consistent image quality.