Re: correct air pressure

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

>References: <3faa6efe.3519dd6a@aol.com>
>Date:         Thu, 26 Mar 1998 09:51:25 -0500
>Reply-To: Medical Physics Mailing List <MEDPHYS@LISTS.WAYNE.EDU>
>Sender: Medical Physics Listserver <medphys@lists.wayne.edu>
>From: "Patrick N. McDermott, Ph.D." <mcdermot@KCI.WAYNE.EDU>
>Subject:      Re: correct air pressure
>To: Multiple recipients of list MEDPHYS <MEDPHYS@LISTS.WAYNE.EDU>
>
>
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>I have recently written a paper entitled "Pitfalls of temperature and
>pressure corrections in radiation dosimetry: a review" (submitted to
>"Medical Physics") which discusses all of the issues raised by
>"Physics92" and Chris Hawkins. I wrote this paper because I have
>personally encountered confusion and mistakes on the part of well
>qualified medical physicists regarding these issues. Furthermore, there
>does not appear to be any comprehensive discussion of this topic in the
>readily available medical physics literature even though this is often
>the single biggest correction that we make to ion chamber readings.
>
>I would be glad to send a preprint. Just send me e-mail at:
>mcdermot@kci.wayne.edu
>
>
>Pat McDermott, Ph.D.
>
>
>
>Physics92 wrote:
>>
>>
>>
>> Dear Medical Physics subscribers,
>>
>> Any comments and/or references on how to correct for altitude and latitute on
>> a barometer calibrated at the sea level would be appreciated. I am interested
>> (for beam calibration) in corrections required by both a mercury and non-
>> mercury barometer. I made an audit at a radiation therapy department and
there
>> was a discrepancy of 20 Hg mm between the readings of the barometer and the
>> air pressure given by the weather service. The "local" physicist says that it
>> is because he made the "corrections" while the weather service gives the sea
>> level pressure; the weather man says that this is the pressure measured in
>> their yard (close to the hospital; so I take it as being the "real" or
>> absolute pressure, the one which I need for Cpt). How do I solve the problem?
>>
>> Thank you in advance for your comments.
>>
>> George Capatina, Ph.D.
>> physics92@aol.com
>