Use of Medical Radiation in Cardiovascular Imaging
Use of Medical Radiation in Cardiovascular Imaging
In the USA, nuclear cardiology accounts for >50% of all nuclear medicine procedures and 85% of the entire cumulative ED due to nuclear medicine, which accounted for 26% of the overall medical exposure of patients in 2006. Table 3 summarizes the ED for commonly performed studies. A number of strategies can be used to minimize dose in cardiac nuclear imaging, such as the use of Tc (technetium) sestamibi or tetrofosmin agents as preferred radiopharmaceuticals in single-photon emission computed tomography (SPECT) and the use in patients with low pre-test probability of disease of stress-first/stress-only protocols. Radiation exposure can be decreased by 75% using a protocol whereby stress imaging is performed first ('stress first'), with rest images eliminated in patients with normal stress images ('stress only')—but in current practice in the USA, it is seldom used due to gaps in practitioners' knowledge pertaining to radiation safety. This same knowledge gap leads to the 15% rate of dual radioisotope testing, which is unacceptably high due to high ED involved (~30 mSv). The new SPECT detectors with cadmium zinc telluride technology can be used to considerably decrease the ED and acquisition time for myocardial perfusion SPECT with preserved image quality. A strategic target of the nuclear cardiology community is that for the population of patients referred for SPECT or positron-emission tomography (PET) myocardial perfusion imaging, on average a total radiation exposure of <9 mSv can be achieved in 50% of studies by 2014.
Nuclear Medicine: Doses and Risks
In the USA, nuclear cardiology accounts for >50% of all nuclear medicine procedures and 85% of the entire cumulative ED due to nuclear medicine, which accounted for 26% of the overall medical exposure of patients in 2006. Table 3 summarizes the ED for commonly performed studies. A number of strategies can be used to minimize dose in cardiac nuclear imaging, such as the use of Tc (technetium) sestamibi or tetrofosmin agents as preferred radiopharmaceuticals in single-photon emission computed tomography (SPECT) and the use in patients with low pre-test probability of disease of stress-first/stress-only protocols. Radiation exposure can be decreased by 75% using a protocol whereby stress imaging is performed first ('stress first'), with rest images eliminated in patients with normal stress images ('stress only')—but in current practice in the USA, it is seldom used due to gaps in practitioners' knowledge pertaining to radiation safety. This same knowledge gap leads to the 15% rate of dual radioisotope testing, which is unacceptably high due to high ED involved (~30 mSv). The new SPECT detectors with cadmium zinc telluride technology can be used to considerably decrease the ED and acquisition time for myocardial perfusion SPECT with preserved image quality. A strategic target of the nuclear cardiology community is that for the population of patients referred for SPECT or positron-emission tomography (PET) myocardial perfusion imaging, on average a total radiation exposure of <9 mSv can be achieved in 50% of studies by 2014.
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