Holmium-166 poly(L-lactic acid) microsphere radioembolisation of the liver: technical aspects studied in a large animal model.
OBJECTIVE
To assess the accuracy of a scout dose of holmium-166 poly(L-lactic acid) microspheres ((166)Ho-PLLA-MS) in predicting the distribution of a treatment dose of (166)Ho-PLLA-MS, using single photon emission tomography (SPECT).


METHODS
A scout dose (60 mg) was injected into the hepatic artery of five pigs and SPECT acquired. Subsequently, a 'treatment dose' was administered (540 mg) and SPECT, computed tomography (CT) and magnetic resonance imaging (MRI) of the total dose performed. The two SPECT images of each animal were compared. To validate quantitative SPECT an ex vivo liver was instilled with (166)Ho-PLLA-MS and SPECT acquired. The liver was cut into slices and planar images were acquired, which were registered to the SPECT image.


RESULTS
Qualitatively, the scout dose and total dose images were similar, except in one animal because of catheter displacement. Quantitative analysis, feasible in two animals, tended to confirm this similarity (r(2) = 0.34); in the other animal the relation was significantly better (r(2) = 0.66). The relation between the SPECT and planar images acquired from the ex vivo liver was strong (r(2) = 0.90).


CONCLUSIONS
In the porcine model a scout dose of (166)Ho-PLLA-MS can accurately predict the biodistribution of a treatment dose. Quantitative (166)Ho SPECT was validated for clinical application.
Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, The Netherlands.
M A D
MA
Vente
T C
TC
de Wit
M A A J
MA
van den Bosch
W
W
Bult
P R
PR
Seevinck
B A
BA
Zonnenberg
H W A M
HW
de Jong
G C
GC
Krijger
C J G
CJ
Bakker
A D
AD
van het Schip
J F W
JF
Nijsen
D000818:Animals; D001918:Brachytherapy / Q000379:methods*; D004195:Disease Models, Animal; D004337:Drug Carriers / Q000737:chemistry; D006695:Holmium / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry; D008099:Liver / Q000378:metabolism*; D008863:Microspheres; D011091:Polyesters; D011108:Polymers / Q000737:chemistry; D011868:Radioisotopes / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics / Q000627:therapeutic use; D013552:Swine; D014018:Tissue Distribution
D004337:Drug Carriers; D011091:Polyesters; D011108:Polymers; D011868:Radioisotopes; D019275:Radiopharmaceuticals; D019344:Lactic Acid; C033616:poly(lactide); D006695:Holmium