Organ Doses to Airline Passengers Screened by X-Ray Backscatter Imaging Systems

Area of Science:

• Medical Physics
• Radiation Safety
• Aerospace Security

Background:

• Advanced imaging technologies (AIT) are crucial for enhancing passenger airline security.
• X-ray backscatter imaging is a key AIT system under consideration for security screening.
• Concerns exist regarding potential health risks from ionizing radiation exposure during AIT scans.

Purpose of the Study:

• To present a Monte Carlo methodology for estimating organ doses from X-ray backscatter AIT systems.
• To calculate organ and effective doses for diverse passenger populations, including adults, children, and fetuses.
• To evaluate the impact of operational parameters and potential failures on radiation safety.

Main Methods:

• Modeled radiological properties of a reference X-ray backscatter scanner (beam intensity, geometry, energy spectra).
• Developed and validated a Monte Carlo source subroutine using simulated versus measured data.
• Utilized computational phantoms representing various adult, pediatric, and fetal morphologies.

Main Results:

• Routine operations resulted in maximum effective doses of 15 nSv (adults) and 25 nSv (pediatrics) per screen.
• Maximum organ and whole-body doses for developing fetuses were 16 nGy and 8.5 nGy per screen, respectively.
• Sensitivity analyses showed doses remained an order of magnitude below ANSI safety recommendations.

Conclusions:

• The developed Monte Carlo method accurately estimates radiation doses from X-ray backscatter AIT.
• Radiation doses associated with AIT passenger screening are well within established safety limits.
• X-ray backscatter imaging presents a low health risk for routine airline security applications.