DEVELOPMENT OF AGE-SPECIFIC JAPANESE PHYSICAL PHANTOMS FOR DOSE EVALUATION IN INFANT CT EXAMINATIONS

Area of Science:

• Medical Physics
• Radiological Science
• Biomedical Engineering

Background:

• Previous development of age-specific Japanese head phantoms laid the groundwork for this study.
• Accurate radiation dose assessment in pediatric computed tomography (CT) is crucial for patient safety.

Purpose of the Study:

• To design and develop age-specific Japanese torso phantoms for accurate dose assessment in infant CT examinations.
• To create a 3-year-old Japanese head-torso phantom for comprehensive dosimetry.
• To validate the developed phantom's accuracy by comparing its dosimetry measurements with simulation data.

Main Methods:

• Anatomical structures of Japanese infants (0, 0.5, 1, and 3 years old) were measured from CT images.
• Radiophotoluminescence glass dosemeters were employed for dose measurements using the 3-year-old head-torso phantom.
• Organ and effective doses measured by the phantom were compared against simulation values from the WAZA-ARI CT dose calculation system.

Main Results:

• CT morphometry revealed that Japanese infants have smaller rib cages compared to European and American infants.
• The developed 3-year-old head-torso phantom demonstrated dosimetry measurements with less than 20% difference compared to WAZA-ARI simulation values.
• This accuracy was observed for organs within scan regions and for effective doses in head, chest, and abdominopelvic CT examinations.

Conclusions:

• The developed Japanese torso phantoms, including the 3-year-old head-torso model, are suitable for accurate dose assessment in infant CT examinations.
• The phantom's dosimetry system provides reliable measurements, validating its use in pediatric CT radiation dose evaluations.
• Findings highlight anatomical differences in Japanese infants, emphasizing the need for region-specific phantoms in radiation dosimetry.