15O-water is not metabolized in the body during a PET study. 15O-water diffuses freely across the cell membrane and is therefore the optimal flow tracer. It has a half-life of 122 seconds, which makes it possible to acquire multiple image scans in rapid sequence.
15O-water has been used as non-invasive gold standard for qualifying a number of methods including myocardial perfusion MR [1] and SPECT [2], FFR [3] and echo [4].
The short half-life of 15O-water further means that the patient radioactivity dose is the lowest achievable and down to 0.4 mSv pr. scan. The worldwide average natural dose to humans is about 2.4 mSv per year.
1. Tomiyama Y, Manabe O, Oyama-Manabe N, Naya M, Sugimori H, Hirata K, Mori Y, Tsutsui H, Kudo K, Tamaki N et al: Quantification of myocardial blood flow with dynamic perfusion 3.0 Tesla MRI: Validation with (15) O-water PET. J Magn Reson Imaging 2015, 42(3):754-762.
2. Ito Y, Katoh C, Noriyasu K, Kuge Y, Furuyama H, Morita K, Kohya T, Kitabatake A, Tamaki N: Estimation of myocardial blood flow and myocardial flow reserve by 99mTc-sestamibi imaging: comparison with the results of [15O]H2O PET. Eur J Nucl Med Mol Imaging 2003, 30(2):281-287.
3. De Bruyne B, Baudhuin T, Melin JA, Pijls NH, Sys SU, Bol A, Paulus WJ, Heyndrickx GR, Wijns W: Coronary flow reserve calculated from pressure measurements in humans. Validation with positron emission tomography. Circulation 1994, 89(3):1013-1022.
4. Dijkmans PA, Knaapen P, Sieswerda GT, Aiazian E, Visser CA, Lammertsma AA, Visser FC, Kamp O: Quantification of myocardial perfusion using intravenous myocardial contrast echocardiography in healthy volunteers: comparison with positron emission tomography. J Am Soc Echocardiogr 2006, 19(3):285-293.
This study measures the absolute myocardial blood flow using PET. It also discusses the characteristics of the radioactive tracers, that are available. It is shown that 15O-water is superior to the other tracers.
This comparative study shows that positron emission tomography (PET), using 15O-water as a tracer, exhibits the highest accuracy for diagnosis of myocardial ischemia.
