15O-water is a very short-lived radioactive version of regular water, in which the oxygen atom has been replaced by oxygen-15, a positron-emitting isotope.

Qualities

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.

Articles

MYOCARDIAL PERFUSION IMAGING WITH PET

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.

COMPARISON OF CORONARY CT ANGIOGRAPHY, SPECT, PET, AND HYBRID IMAGING FOR DIAGNOSIS of ISCHEMIC HEART DISEASE DETERMINED BY FRACTIONAL FLOW RESERVE

This comparative study shows that positron emission tomography (PET), using 15O-water as a tracer, exhibits the highest accuracy for diagnosis of myocardial ischemia.

QUANTITATIVE ASSESSMENT OF MYOCARDIAL PERFUSION IN THE DETECTION OF SIGNIFICANT CORONARY ARTERY DISEASE

This study examines the cutoff values for absolute MBF and to evaluate the diagnostic accuracy of quantitative 15O-water positron emission tomography (PET). It concludes that the use of 15O-water in PET provides high diagnostic performance for quantitative MBF measurements.

Scientific Applications for 15O-Water

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Cardiology

Neurology

Oncology

Endocrinology

Systems biology

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”The availability of a reliable approved system for bed-side production of 15O-water could change 15O-water PET from an exotic research tool to a clinical workhorse”

Martin Stenfeldt, CEO, MedTrace Pharma