(18)F-fluoride PET for monitoring therapeutic response in Paget's disease of bone.
A prospective study was undertaken to evaluate PET with (18)F-fluoride for monitoring the response to bisphosphonates in Paget's disease of bones.


METHODS
Fourteen patients with a monostotic (n = 9) or a polyostotic form (n = 5) of Paget's disease were scanned at baseline and at 1 and 6 mo after the beginning of treatment. Dynamic acquisition and arterial blood sampling were used to calculate the influx constant Ki (by both the Patlak [Ki-PAT] method and the nonlinear regression [Ki-NLR] method). Kinetic modeling was compared with maximal standardized uptake values (SUV(max)) and biochemical markers of bone remodeling.


RESULTS
Baseline uptake of (18)F-fluoride by pagetic bones was significantly higher than in normal bones (P < 0.05). One month after the start of treatment, SUV(max), Ki-PAT, Ki-NLR, and K(1) (the unidirectional clearance of fluoride from plasma to the whole of the bone tissue) decreased significantly by 27.8%, 27.9%, 27.5%, and 23.6%, respectively. Biochemical markers were already normalized in 6 of 9 patients with monostotic disease, although all had high (18)F-fluoride uptake values. Six months after the start of treatment, (18)F-fluoride uptake further diminished by 22.3%-25.6%. Biochemical markers were normal in all but 2 patients, although 10 of 14 patients still showed high (18)F-fluoride uptake. One patient did not respond to treatment and maintained high uptake of (18)F-fluoride throughout the study. SUV(max) correlated with both Ki-PAT and Ki-NLR at baseline, 1 mo, and 6 mo (P < 0.05). Moreover, the change of SUV(max) between baseline and 1 mo, as well as between baseline and 6 mo, also correlated with the change of Ki-PAT and Ki-NLR (P < 0.05).


CONCLUSIONS
Our results show that (18)F-fluoride PET can be used to noninvasively and accurately monitor the efficacy of treatment with bisphosphonates in Paget's disease of bones. SUV(max) correlates with Ki-PAT and Ki-NLR and, interestingly, varies in the same manner as kinetic indices. Therefore, the use of SUV(max) could avoid the need for dynamic acquisition and arterial blood sampling and would facilitate the use of whole-body PET in a clinical setting.
Installé
Johanne
J
Department of Molecular Imaging and Experimental Radiotherapy, Catholic University of Louvain, Brussels, Belgium.
Nzeusseu
Adrien
A
Bol
Anne
A
Depresseux
Geneviève
G
Devogelaer
Jean-Pierre
JP
Lonneux
Max
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D050071:Bone Density Conservation Agents / Q000627:therapeutic use; D004164:Diphosphonates / Q000627:therapeutic use*; D005240:Feasibility Studies; D005260:Female; D005459:Fluorides; D005462:Fluorine Radioisotopes; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010001:Osteitis Deformans / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016896:Treatment Outcome
D050071:Bone Density Conservation Agents; D004164:Diphosphonates; D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; D005459:Fluorides