Re: treating acne with xrays

[Mike Grissom <mikeg@SLAC.Stanford.EDU>]

Radsafers,

When I responded to Jim Barnes privately I was
dredging up ancient memories (it has been years
since I observed an installed grenz-ray machine).

The kVp for the last unit I saw had an indicated
range of 0 (starting point, cut-off probably was
about 5 kVp as stated earlier) to at least the
20s of kVp.  I believe Ron and others were correct
that 5-20 kVp was the likely usual operational
range.

I have seen these units installed in older radiation
therapy and dermatology departments.  None of the
units that I have seen were operational!  The original
manufacturers had left the business and the biomedical
repair staffs refused to service them!  This frustrated
the dermatologists more than the therapeutic radiologists.
In general, grenz rays were used to treat benign disease,
that is, non-neoplastic conditions.  Usually these were
skin lesions such as severe cases of dermatitis, which
are conditions most therapeutic radiologists don't like to
use radiation to treat for.

The therapeutic radiologists did (and some still) do some superficial
radiotherapy using orthovoltage x-ray machines, such as the one Aggie
mentions in the message below.  These are industrial strength high
performance x-ray tubes that can be continuously operated in a manner
similar to the x-ray devices used in radiography of material
(non-destructive testing).

I believe Bill Hendee's textbook on Medical Physics gives
the particulars for grenz and orthovoltage (don't have it handy here!).

An observation,

S.,

MikeG.


At 01:37 PM 9/16/97 -0500, you wrote:
>
>Long ago when I worked in a hospital Radiology Dept., we did these 
>treatments.  [late 1960's and early '70's ]  The equipment used for these 
>treatments was one with a range of ~50-120 Kvp - not Grenz range.  A 
>significant deep dose was being delivered along with treating the 
>superficial condition.
>
>Aggie
>Agnes.Barlow@yale.edu
>standard disclaimer


Michael P. Grissom
Asst Dir (ES&H)
SLAC MS-84
Phone: (650) 926-2346
Fax:   (650) 926-3030
E-mail: mikeg@slac.stanford.edu