Scatter radiation intensities about mammography units

Area of Science:

• Medical Physics
• Radiological Imaging
• Radiation Dosimetry

Background:

• Mammography utilizes X-rays for breast cancer screening, generating scattered radiation.
• Quantifying scattered X-rays is essential for understanding image quality and patient dose.
• Previous studies have explored scatter characteristics, but detailed analysis across various angles and units is ongoing.

Purpose of the Study:

• To measure scattered X-ray intensity and scatter fraction from clinical mammographic units.
• To analyze the influence of kilovoltage peak (kVp) and scattering angle on scatter.
• To compare scatter characteristics between different mammography units and assess forward scatter dependence on equipment design.

Main Methods:

• Scattered X-ray intensity was measured at various angles (0-163 degrees) using two clinical mammographic units at 25, 30, and 35 kVp.
• Scatter fraction was calculated as the ratio of scatter dose to primary dose at 1 meter per primary X-ray field area.
• Dose to adjacent areas was estimated based on measured scatter.

Main Results:

• Backscatter (163 degrees) scatter fraction was 4-7 times greater than 90-degree scatter.
• Scatter fraction ranged from 0.01 x 10^-6 cm^-2 to 1.7 x 10^-6 cm^-2 across angles and units.
• Forward scatter showed a sharp increase around 25 degrees, dependent on image receptor and collimator design.
• Differences between units were <10% for angles >45 degrees.

Conclusions:

• Scatter fraction in mammography is highly dependent on scattering angle, particularly significant at backward angles.
• Equipment design, especially collimators and image receptors, influences forward scatter.
• The findings provide a basis for estimating radiation dose in occupied areas surrounding mammography equipment.