Radiation dose reduction by adjusting bolus tracking parameters in a 320-detector row scanner.
J Cardiovasc Comput Tomogr. 2018 Jul - Aug;12(4):312-315. doi: 10.1016/j.jcct.2018.03.009. Epub 2018 Apr 5. Matsumoto JKN1, Assuncao-Jr AN2, Dantas Junior RN3, Araujo-Filho JAB4, Andrade SS5, Nomura CH6, Parga JR7.
BACKGROUND: The importance of bolus tracking (BT) regarding total effective radiation dose (ERD) in the era of advanced coronary computed tomography angiography (CTA) has been ignored. We aimed to investigate whether adjusting BT parameters reduces ERD.
METHODS: Adults consecutively referred to CTA (n = 289) in a 320 detector-row scanner were distributed into four BT protocols according to delay time and time between intermittent scans, as follows: A (n = 70, delay 10s, intermittent scans 1s); B (n = 79, delay 10s, intermittent scans 2s); C (n = 68, delay 15s, intermittent scans 1s); and D (n = 72, delay 15s, intermittent scans 2s). Image quality was assessed.
RESULTS: The overall ERD in BT and AP were 0.32 ± 0.14 mSv and 6.06 ± 0.66 mSv, respectively. ERD in BT was different among protocols (A:0.44 ± 0.14 mSv; B:0.32 ± 0.10 mSv; C:0.28 ± 0.14 mSv; D:0.23 ± 0.09 mSv; p < 0.001), with no loss in image quality. Adjusted for potential confounders (heart rate, tube current and acquisition window), protocol D provided the highest reduction in total ERD (β = -0.33, p = 0.004).
CONCLUSION: Delaying initiation of BT images (and acquiring them less frequently) reduces radiation dose and does not impair image quality.