Functional CT imaging of the acute hyperemic response to radiation therapy of the prostate gland: early experience.
OBJECTIVE
Functional CT can measure perfusion and permeability. We hypothesized that acute changes could be measured in these indexes following radiation therapy (RT) to the prostate gland.


METHODS
Twenty-two patients with prostatic cancer were studied before and 1-2 and 6-12 weeks after RT. A single section through the prostate was repeatedly scanned after contrast medium bolus injection. Contrast agent clearance per unit volume (alpha/V) and fractional vascular volume (fvv) were calculated using Patlak graphical analysis. Perfusion was calculated as the ratio between maximal rate of tissue enhancement and peak arterial enhancement.


RESULTS
Significant increases in all indexes occurred after RT. Mean perfusion rose from 0.122 to 0.263 ml/min/ml at 1-2 weeks, mean alpha/V increased from 0.0012 to 0.0016 ml/min/ml at 1-2 weeks, and mean fvv increased from 13.7 to 21% at 1-2 weeks. All three indexes remained elevated at 6-12 weeks after the start of RT.


CONCLUSIONS
Functional CT demonstrated an acute hyperemic response following RT to the prostate gland.
Harvey
C J
CJ
Department of Imaging, Imperial College School of Medicine, Hammersmith Hospital, London, UK. charvey_99@yahoo.com
Blomley
M J
MJ
Dawson
P
P
Morgan
J A
JA
Dooher
A
A
Deponte
J
J
Vernon
C C
CC
Price
P
P
D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D006940:Hyperemia / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000150:complications / Q000532:radiotherapy*; D011878:Radiotherapy / Q000009:adverse effects; D014057:Tomography, X-Ray Computed