Absorbed radiation dose in radiosensitive organs using 64- and 320-row multidetector computed tomography: a...

Area of Science:

• Medical Imaging
• Radiological Physics
• Radiation Dosimetry

Background:

• Minimizing radiation exposure is crucial in medical imaging, especially for radiosensitive organs.
• ECG-gated MDCTA scanners offer dose modulation techniques to reduce patient radiation dose.
• Detector row configurations (e.g., 64-row vs. 320-row) can impact radiation dose distribution.

Purpose of the Study:

• To compare the absorbed radiation dose (ARD) in radiosensitive organs using prospective and full-phase dose modulation techniques.
• To evaluate the impact of 64-row versus 320-row detector modes on ARD during ECG-gated MDCTA.
• To determine optimal scanning parameters for dose reduction.

Main Methods:

• A female phantom was utilized to measure organ radiation dose.
• Five DP-3 radiation detectors measured ARD in the lungs, breast, and thyroid.
• The Aquilion ONE scanner was used in 64- and 320-row modes with prospective and retrospective gating.
• Measurements were conducted at varying tube voltages (100, 120, 135 kVp), current (400 mA), and heart rates (60, 75 bpm).

Main Results:

• The 320-row mode consistently showed lower ARD than the 64-row mode across all imaging protocols.
• Prospective gating with the 320-row mode yielded significantly lower ARD for mid-breast, lung, and thyroid compared to the 64-row mode (P < 0.001).
• Retrospective gating also demonstrated lower ARD with the 320-row mode compared to the 64-row mode (P < 0.001).
• Lower kVp and heart rate settings further reduced ARD.

Conclusions:

• The 320-row detector mode offers superior dose reduction for radiosensitive organs compared to the 64-row mode in ECG-gated MDCTA.
• Both prospective and retrospective gating protocols benefit from the 320-row configuration for dose optimization.
• The 64-row mode's performance was comparable to other 64-row MDCT scanners.