Calculator Input
Example Data Table
| Case | Output mGy/mAs | mAs | Reference cm | Skin cm | Attenuation | Incident Kerma mGy |
|---|---|---|---|---|---|---|
| Low exposure | 0.045 | 60 | 65 | 60 | 0.94 | 3.17 |
| Standard view | 0.050 | 80 | 65 | 60 | 0.92 | 4.31 |
| Dense breast view | 0.058 | 110 | 65 | 58 | 0.90 | 7.20 |
Formula Used
Incident Air Kerma = Tube Output × mAs × (Reference Distance ÷ Focus Skin Distance)² × Attenuation Factor × Conversion Factor
Entrance Surface Air Kerma = Incident Air Kerma × Backscatter Factor
Total Incident Air Kerma = Incident Air Kerma × Number of Exposures
Area Kerma Product = Incident Air Kerma × Irradiated Breast Area
How to Use This Calculator
Enter the tube output from your calibration record.
Add the mAs used for the breast exposure.
Enter the reference distance for the tube output.
Add the focus to skin distance used during imaging.
Use correction factors when they are available.
Keep any unavailable correction factor as one.
Press calculate to view the result above the form.
Use CSV or PDF export for documentation.
About Incident Air Kerma to the Breast
Purpose of the Calculator
This calculator estimates incident air kerma for breast imaging work. It is designed for conversion, review, and documentation tasks. The result helps compare exposure settings in a structured way. It does not replace a calibrated dosimetry system. It also does not provide a patient risk statement.
What the Result Means
Incident air kerma describes air kerma before backscatter is added. It is often calculated near the breast entrance surface. The value depends on tube output, mAs, and distance. It also changes when filters or correction factors are applied. A higher mAs usually gives a higher kerma result. A shorter focus to skin distance also increases the estimate.
Advanced Input Options
The calculator includes several useful input fields. Tube output represents calibrated output per mAs. Reference distance is the distance used during calibration. Focus to skin distance is the clinical measurement. Backscatter factor estimates entrance surface air kerma. Attenuation factor can represent filtration or beam correction. Conversion factor helps align units or calibration records. Breast thickness and area add extra reporting values.
Practical Review Use
The tool can support repeatable exposure reviews. It can compare views, techniques, or protocol changes. It can also prepare simple records for audits. CSV export is useful for spreadsheets. PDF export is useful for reports. Example rows show how typical entries may look. Always verify local measurement methods before using results.
Important Safety Note
Breast dosimetry is a specialized clinical physics task. Final values should use approved equipment and procedures. Local protocols may define different correction factors. Mean glandular dose requires additional factors. This calculator estimates incident air kerma only. Use it as an educational and documentation aid. Consult qualified professionals for clinical decisions.
FAQs
What is incident air kerma?
Incident air kerma is the air kerma at the entrance point before backscatter is included. It is commonly used in imaging dose review.
Is this the same as absorbed breast dose?
No. Absorbed breast dose and mean glandular dose require more information. This calculator estimates incident air kerma only.
What does tube output mean?
Tube output is the measured radiation output per mAs at a known reference distance. It usually comes from calibration records.
What should I enter for backscatter factor?
Use a value from your local protocol or measurement method. If you only need incident air kerma, you may enter one.
Why is distance important?
Radiation intensity changes with distance. The calculator applies an inverse square correction between reference and skin distance.
Can I use this for mammography checks?
It can support educational or documentation checks. Clinical quality assurance should follow approved protocols and qualified expert review.
What if I do not know attenuation factor?
Enter one when no attenuation or filtration correction is being applied. This keeps the calculation neutral.
Can I export the calculation?
Yes. Use the CSV button for spreadsheet records. Use the PDF button for a simple printable report.