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Introduction Radiation exposure in cardiac imaging is an important healthcare concern. For patients with stable chest pain this includes computed tomography (CT) coronary angiography (CTCA), coronary artery calcium score (CACS), single photon emission tomography (SPECT) and invasive angiography (ICA). Methods Radiation dose data for 1000 consecutive patients from the SCOT-HEART trial were obtained from electronic patient records. Radiation dose from the first occurrence of each form of imaging was recorded including dose area product (DAP) for ICA, dose length product (DLP) for CT and injected activity (megabecquerel, MBq) for SPECT (99 mTc tetrofosmin). Conversion factors to calculate effective dose were 0.024 for ICA, 0.028 for CT and 0.009 for SPECT. Results Patients had a mean age 57±10 years, body mass index 29±6 kg/m2 and 57% were male. ICA was performed in 337 patients with a median DAP of 181.7 [IQR 129.2, 279.8] mCycm2 for diagnostic imaging and 430.6 [IQR 299.5, 612.1] mCycm2 when percutaneous coronary intervention was also performed. SPECT was performed in 52 patients with a median total injected activity of 988 [IQR 954, 1137] MBq. CT was performed in 441 patients with a median total DLP of 276 [IQR 210, 353] mGy.cm. Median radiation dose for CACS was 115 [102, 125] mGy.cm and CTCA was 191 [IQR 100, 293] mGy.cm. Effective radiation doses were 4.4 mSv for diagnostic ICA, 5.4 mSv for CTCA and 8.9 mSv for SPECT. Conclusion Radiation dose for diagnostic imaging for stable chest pain was similar for CTCA and ICA and highest for SPECT. |
