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Human Prostate (PPC-1)
Archive, Prostate

Reference: Deweese TL, Shipman JM, Dillehay LE, and Nelson WG. Sensitivity of human prostatic carcinoma lines to low dose rate radiation exposure. Journal of Urology. 159, 591-598 (1998).

Data: Microsoft Excel spreadsheet and as a webpage

PPC-1 human prostate carcinoma cells were irradiated by gamma-rays from Cs-137 (dose rates of 0.25 and 60 Gy/hour).  Measured data (filled symbols) were digitized from the published figures using UnGraph.  The calibrated LPL, RMR, and TLK input files give equally good fits to the measured data as a function of dose and dose rate (solid black lines in the surviving fraction vs. dose plot; see below).  The LQ model also provides an adequate fit to the available data.

Analysis:
 
VC Input Files VC Output Files
LQ Model: An LQ analysis of the PPC-1 data yields point estimates of a and a/b equal to 0.160 Gy-1 and 2.485 Gy, respectively.  The 95% confidence interval for a/b is (1.892 Gy, 3.051 Gy).  The point estimate for the repair half-time is 8.405 h, and the 95% confidence interval is (7.681 h, 8.704 h).  The paired bootstrap technique for regression (Efron 1979) was used to compute 95% confidence intervals for the estimated radiosensitivity parameters.
 

Tip: The LQ is a low dose, low dose rate approximation for the LPL and RMR models (see Brenner et al. 1998, Guerrero et al. 2002, Sachs et al. 1997).

Click on figure to enlarge

Click on figure to enlarge

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Last updated: 10 June, 2011
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