Spiral CT and radiation dose

Area of Science:

• Radiology
• Medical Physics
• Radiation Protection

Background:

• Computed Tomography (CT) scans constitute a small fraction of radiological exams (3-5%) but account for a significant portion of patient radiation dose (35-45%).
• Existing methods for measuring CT radiation dose, such as the Computed Tomography Dose Index (CTDI), have modifications leading to potential confusion.

Purpose of the Study:

• To address concerns regarding high radiation doses from CT scans.
• To advocate for standardized dose measurement and reporting in CT examinations.
• To guide radiologists in optimizing radiation dose while maintaining diagnostic image quality.

Main Methods:

• Review of current practices and studies on CT radiation dose.
• Recommendation of standardized dose metrics: CTDI-100 w. and dose length product.
• Emphasis on utilizing low kV and mA settings with high pitch, alongside dose-reduction software and filters.
• Comparison of patient doses with national and European reference doses.

Main Results:

• CTDI, established in 1981, has several modifications causing confusion.
• Standardized CTDI-100 w. and dose length product are proposed for consistent patient dose evaluation.
• Optimizing imaging parameters (low kV, mA, high pitch) and employing dose-reduction technologies can decrease radiation exposure.
• Critical review of indications and comparison with reference doses are essential for dose management.

Conclusions:

• Standardized reporting of CTDI-100 w. and dose length product is essential for individualized patient dose evaluation.
• Radiologists must aim for the lowest acceptable signal-to-noise ratio to minimize radiation dose.
• Implementing dose-reduction strategies and critically assessing examination indications are vital for patient safety.