Intraoperative radiation therapy in liver tissue in a pig model: monitoring with dual-modality PET/CT.
OBJECTIVE
To assess, in a pig model, the value of dual-modality positron emission tomography (PET)/computed tomography (CT) for monitoring radiation therapy.


METHODS
Central bile duct resection followed by creation of a biliodigestive anastomosis was performed in nine pigs. Six of these pigs were also treated with intraoperative radiation therapy (IORT) (20 Gy) in the area of the anastomosis. Two, 4, and 8 weeks postoperatively, contrast material-enhanced fluorine 18 fluorodeoxyglucose (FDG) PET/CT of the liver was performed in all of the animals. The radioactive tracer concentration in the region of the anastomosis was quantified, and the values were compared intraindividually with the values at the liver periphery. Histologic evaluation of the liver was performed 8 weeks postoperatively. The PET/CT images were assessed for changes in liver volume and bile duct diameter over time.


RESULTS
In all nine pigs, the region of the anastomosis could be clearly defined on the fused PET/CT images. PET/CT revealed a decreased concentration of FDG in the irradiated field 2 and 4 weeks after IORT. At 8 weeks, however, the distribution of the tracer in the irradiated pigs did not differ from that in the nonirradiated pigs. Homogeneous tracer uptake in all liver regions was observed in the nonirradiated animals. The CT images showed an increase in liver volume in all pigs and bile duct dilatation that increased over time in the irradiated pigs.


CONCLUSIONS
The morphologic and functional changes due to IORT in liver tissue can be accurately monitored with dual-modality PET/CT. By enabling the integration of functional and morphologic data, PET/CT may have an important role in monitoring radiation treatment.
Antoch
Gerald
G
Department of Diagnostic and Interventional Radiology, University Hospital Essen, Germany. gerald.antoch@uni-essen.de
Kaiser
Gernot M
GM
Mueller
Andrea B
AB
Metz
Klaus A
KA
Zhang
Hongwei
H
Kuehl
Hilmar
H
Westermann
Stephanie
S
Broelsch
Christoph E
CE
Mueller
Stefan P
SP
Bockisch
Andreas
A
Debatin
Jörg F
JF
D000713:Anastomosis, Roux-en-Y; D000818:Animals; D017734:Bile Ducts, Extrahepatic / Q000528:radiation effects* / Q000601:surgery*; D001918:Brachytherapy / Q000295:instrumentation; D003131:Combined Modality Therapy; D004108:Dilatation, Pathologic / Q000473:pathology; D004734:Energy Metabolism / Q000528:radiation effects; D005260:Female; D019788:Fluorodeoxyglucose F18; D006499:Hepatic Artery / Q000473:pathology / Q000528:radiation effects*; D006500:Hepatic Duct, Common / Q000473:pathology / Q000528:radiation effects*; D007090:Image Interpretation, Computer-Assisted; D007583:Jejunum / Q000528:radiation effects* / Q000601:surgery*; D008099:Liver / Q000473:pathology / Q000528:radiation effects*; D008115:Liver Regeneration / Q000528:radiation effects; D009336:Necrosis; D010315:Particle Accelerators; D011169:Portal Vein / Q000473:pathology / Q000528:radiation effects*; D011833:Radiation Injuries, Experimental / Q000175:diagnosis* / Q000473:pathology; D012680:Sensitivity and Specificity; D013552:Swine; D014055:Tomography, Emission-Computed; D014057:Tomography, X-Ray Computed
D019788:Fluorodeoxyglucose F18