Changes in vascularity and blood volume as a result of photodynamic therapy can be assessed with power Doppler ultrasonography.
OBJECTIVE
One principal mechanism of photodynamic therapy (PDT) in tumors is destruction of tumor-associated vasculature. In the present study, the vascular effects of PDT in tumors were investigated with power Doppler ultrasonography.


METHODS
Seven cutaneous squamous cell carcinomas in cats were treated. Tumors were examined via power Doppler ultrasonography before, 5 minutes, 1 hour, and 24 hours after PDT. Images were digitized for computer-aided assessment of vascularity and blood volume.


RESULTS
Mean baseline tumor vascularity and blood volume were moderate. During PDT, a significant decrease in vascularity and blood volume was noted. Lowest values were found 24 hours after PDT.


CONCLUSIONS
Power Doppler ultrasonography represents a non-invasive modality to successfully monitor the vascular effects and thus, treatment efficacy, of PDT.
Ohlerth
Stefanie
S
Section of Diagnostic Imaging and Radio-Oncology, Vetsuisse Faculty, University of Zürich, 8057 Zürich, Switzerland. sohlerth@vetclinics.unizh.ch
Laluhová
Dagmar
D
Buchholz
Julia
J
Roos
Malgorzata
M
Walt
Heinrich
H
Kaser-Hotz
Barbara
B
D000818:Animals; D001810:Blood Volume; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000503:physiopathology; D002415:Cats; D005260:Female; D007091:Image Processing, Computer-Assisted; D008297:Male; D008652:Mesoporphyrins / Q000627:therapeutic use; D009389:Neovascularization, Pathologic; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use; D012867:Skin / Q000098:blood supply*; D012878:Skin Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000503:physiopathology; D018608:Ultrasonography, Doppler
D008652:Mesoporphyrins; D017319:Photosensitizing Agents; C072269:temoporfin