Re: Fluoroscope Measurements

[Chris Alston <alstonc@odrge.odr.georgetown.edu>]

>X-Sender: zamenhof@po9.mit.edu (Unverified)
>Date:         Sun, 23 Nov 1997 10:13:41 -0400
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>From: "Robert G. Zamenhof" <zamenhof@MIT.EDU>
>Subject:      Re: Fluoroscope Measurements
>To: Multiple recipients of list MEDPHYS <MEDPHYS@LISTS.WAYNE.EDU>
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>My inclination is to leave the grids in when making QA measurements.  For
>the consistency of my records I make the arbitrary assumption that the
>exposure input to the II is 1/3 the exposure at the grid; that seems good
>enough for tracking things with time and for seeing how the exposure at the
>II/grid varies with various other factors (kVp, II diameter, etc.).
>However, when I am doing an ACCEPTANCE test on a fluoro unit, I DO remove
>the grid because then I am keen to know the absolute exposure rate at the
>II entrance phosphor.
>
>Robert G. Zamenhof, Ph.D.
>Director, Section of Radiological Physics
>Department of Radiology
>Beth Israel Deaconess Medical Center, Harvard Medical School
>1 Deaconess Road, Boston, MA 02215, U.S.A.
>Tel: (617) 667-0175  Fax: (617) 975-5233  E-Mail: zamenhof@mit.edu or
>rzamenho@bidmc.harvard.edu  Beeper (Global): (888) 353-4455
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