Incorporating multislice imaging into x-ray CT polymer gel dosimetry

Area of Science:

• Medical Physics
• Radiotherapy
• Imaging Technology

Background:

• Accurate dose distribution measurement is crucial in radiation therapy (RT).
• CT polymer gel dosimetry (PGD) is a method for measuring RT dose distributions.
• Evaluating advanced imaging techniques for PGD is essential for improving accuracy and efficiency.

Purpose of the Study:

• To assess multislice computed tomography (CT) scanning for rapid and dependable readout of RT dose distributions using CT PGD.
• To establish a baseline for image noise and uniformity in unirradiated gel dosimeters with multislice CT.

Main Methods:

• Images were acquired using a 16-slice CT scanner and a single-slice machine for comparison.
• A novel slice-by-slice background subtraction technique was developed to correct for CT number variability.
• Image quality, noise, uniformity, and scan time were evaluated for both systems.

Main Results:

• Slice-by-slice background subtraction effectively removed artifacts in multislice CT PGD.
• Multislice CT scanning reduced scan time by a factor of 4 and eliminated variations due to x-ray tube load.
• While image noise was higher in multislice CT, overall image quality was comparable to single-slice CT.

Conclusions:

• Multislice CT imaging is a superior technique for CT PGD compared to single-slice imaging.
• The method offers significant advantages in scan time and tube load characteristics.
• Multislice CT scanning is expected to facilitate routine gel dosimetry for complex dose distributions in RT centers.