STUDY ON A SPECIFIC TEST METHOD FOR DOSIMETRIC CHARACTERIZATION OF ULTRA-WIDE DETECTOR COMPUTED TOMOGRAPHY

Area of Science:

• Medical Physics
• Radiological Imaging
• Dosimetry

Background:

• Accurate radiation dose measurement is crucial for computed tomography (CT) safety.
• Previous methods underestimated the computed tomography dose index (CTDI) for wide-beam CT.
• A standardized dosimetric characterization method for wide-beam CT was lacking.

Purpose of the Study:

• To establish a specific and accurate test method for the dosimetric characterization of wide-beam CT.
• To address the underestimation of CTDI values in previous measurement techniques.

Main Methods:

• Utilized a pencil-like ionization chamber and a long CT dose profiler probe.
• Employed head and body phantoms to measure dose distribution curves for wide beams.
• Calculated the absolute dose conversion coefficient and integrated dose distribution to determine CTDI.

Main Results:

• Determined an absolute dose conversion coefficient of 1.135 for an 8 mm narrow beam.
• Measured CTDI values of 7.57 mGy/100mAs (head, 80 kV) and 9.80 mGy/100mAs (body, 120 kV) for a 160 mm wide beam.
• The new method accurately quantifies CTDI, resolving previous underestimation issues.

Conclusions:

• The developed specific test method provides accurate dosimetric characterization for wide-beam CT.
• This method ensures reliable computed tomography dose index (CTDI) measurements, enhancing radiation safety.
• The findings facilitate more precise dose assessment in modern wide-beam CT examinations.