Re: Gamma Ray Constant for F-18

["David Whitfill" <DWhitfil@kdhe.state.ks.us>]

The handbook of Health Physics and Radiological Health, 3rd ed., gives this
value for F-18:

1.879E-04 mSv-m^2 per h-MBq = 6.95 rem-cm^2/h-mCi

If you assume 1 rem = 1 rad = 1 R you're finished, but..

X air, R = D tissue, rad/(0.87 rad/R) x (uen/p air)/(uen/p tissue)

Using an energy of 500 keV (close to 511 keV), the energy-absorption
coefficients are 2.966E-02 cm^2/g for air and

3.304E-02 cm^2/g for adipose tissue (RHH 5-24,25) and the correction factor
with 1 rem = 1 rad is 1.03:

7.16 rem-cm^2/h-mCi

=============================================
>I am looking for the true Gamma Ray Constant for F-18 in the nostalgic
units of R/hr-cm^2/mCi.  There have been values reported in the range of
5.7 - 8.  Can anyone pin it down for me?
>
Scott Dube
sdube@queens.org

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