OBJECTIVE: This study aimed to evaluate the application value of personalized patient protocol technology (P3T) modular cardiac injection technique combined with the iterative reconstruction algorithm, sinogram-affirmed iterative reconstruction (SAFIRE) in coronary computed tomography angiography (CCTA). METHODS: A retrospective analysis was performed on 40 patients who underwent CCTA at the Central Hospital Affiliated to Shandong First Medical University. Patients were divided into two groups: control group (n=20), which received the traditional contrast agent injection with fixed iodine load and injection flow rate, and filtered back projection reconstruction with filtered back projection (FBP), and experimental group (n=20), which employed a dosing protocol calculated based on P3T cardiac modular parameters, with SAFIRE strength 3 reconstruction. The two groups were compared regarding CT values (proximal, middle, and distal segments), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), coronary imaging quality score, contrast agent flow rate, injection volume, and effective radiation dose (ED). RESULTS: There were no significant differences in CT values of the right coronary artery, anterior descending artery, or circumflex artery at the proximal and middle segments between the two groups (P>
0.05). However, the experimental group exhibited significantly higher CT values at the distal segments of these coronary arteries compared to the control group (P<
0.05). SNR, CNR, and coronary imaging quality scores showed no significant differences between the two groups (P>
0.05). The contrast agent flow rate and injection volume in the experimental group were significantly lower than those in the control group (P<
0.05). Additionally, the volume CT dose index (CTDIvol), dose length product (DLP), and ED were significantly reduced in the experimental group compared to the control group (P<
0.05). CONCLUSION: The combination of P3T technology with SAFIRE reconstruction in CCTA effectively reduces contrast agent flow rate, injection volume, and radiation dose without compromising image quality. This approach enables individualized, standardized, and consistent injection schemes.