Relationships between patient size, dose and image noise under automatic tube current modulation systems

Area of Science:

• Medical Imaging
• Radiological Physics

Background:

• Automatic tube current modulation (ATCM) is standard in CT imaging.
• Manufacturer-specific ATCM principles affect image noise and patient dose.
• Understanding these differences is crucial for CT dose optimization.

Purpose of the Study:

• To survey and analyze CT patient doses across different manufacturers.
• To investigate the relationship between patient size, ATCM, and image noise.
• To compare dose optimization strategies among leading CT scanner brands.

Main Methods:

• Surveyed CT patient doses on 14 scanners from four manufacturers.
• Analyzed patient cross-sectional area, ATCM settings, and image noise using custom software.
• Compared dose and modulation behaviors across different scanner models.

Main Results:

• Toshiba and GE scanners maintained consistent noise but showed dose increases with patient size.
• Philips and Siemens scanners exhibited less dependence on patient size for tube current, resulting in lower doses for larger patients.
• Image noise was found to be more dependent on patient size in Philips and Siemens systems.

Conclusions:

• CT scanner manufacturer significantly influences patient dose optimization via ATCM.
• Toshiba/GE approaches can lead to substantially higher doses for larger patients compared to Philips/Siemens.
• Tailoring ATCM knowledge to specific scanner models is essential for effective CT dose reduction.