Non-invasive assessment of skeletal kinetics using fluorine-18 fluoride positron emission tomography: evaluation of image and population-derived arterial input functions
Gjr. Cook et al., Non-invasive assessment of skeletal kinetics using fluorine-18 fluoride positron emission tomography: evaluation of image and population-derived arterial input functions, EUR J NUCL, 26(11), 1999, pp. 1424-1429
Citations number
16
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
To measure regional skeletal kinetics using fluorine-18 fluoride positron e
mission tomography (PET) it is necessary to know the concentration of radio
active tracer being delivered to bone by arterial plasma with relation to t
ime, the arterial input function (IFa). Methods by which IFa can be derived
without arterial sampling are attractive because of their relative technic
al simplicity and the reduction in possible morbidity to the subject. We ha
ve compared the use of a scaled population input function (IFp) and a corre
cted image-derived input function from the aorta (IFi) with an IFa directly
measured from a radial artery line in ten normal postmenopausal women. Bot
h of the aforementioned methods rely only on a small number of discrete ven
ous samples. Each subject had a dynamic PET acquisition of the lumbar spine
performed after the intravenous injection of 180 MBq F-18-fluoride. Both t
he IFp and the IFi were compared with the IFa in terms of the accuracy of d
etermination of six parameters. These were: plasma clearance of fluoride to
bone mineral (K-i), unidirectional plasma clearance to total bone tissue (
K-1) and individual rate constants k(2), k(3) and k(4), calculated using no
n-linear regression with a three-compartment model, and the plasma clearanc
e to bone mineral calculated using the Patlak method (K-pat). For both the
IFp and the IFi method the root mean square errors for K-pat and K-i were s
imilar and small (<8.2%). The errors in determining K-i and the rate consta
nts k(2) to k(4) are larger by either method, but with a small advantage us
ing the IFp method, It is concluded that the use of either non-invasive met
hod for determining the arterial plasma input function is suitable for the
measurement of the most important parameters, K-i and K-pat, in these subje
cts.