[Oradlist] Tube heads replacement

[Andrews, Paul]

Dear Dr Ahmad,

 

Dental is different from Medical in that you have to replace the entire
tubehead with the same model from the original manufacturer - you cannot
replace a "generic" x-ray tube like you can in medical. This is because the
whole tubehead unit is vacuum sealed with insulating oil (unless it is a
"DC" machine), and the mounting system for each different manufacturer is
unique, plus the machines have been FDA approved to operate together as a
certified system, with all components matching. On each machine you will
have small metal plates or labels, attached to the control, tubehead, and
cone or collimating device. You need to go to the manufacturer (or a dealer
who does business with those manufacturers) of each of those x-ray machines,
and have the following information ready when placing your order: 

 

*	model number (most important)
*	serial number
*	date of manufacture

 

The last two are also important because some manufacturers have changed
specifications internal to their product, but kept the same model numbers.
This is usually a concern only with controls, but it is possible that there
might be changes to the other certified components as well (i.e. internal
filtration, collimating device mounts, etc). They keep track of differences
in specifications by serial number and/or date of manufacture. 

 

There are several other things to consider, before replacing just the
tubeheads: how old is the machine, and is your model number still in
production? Once a model is discontinued, manufacturers are only obligated
by law to support it for 10 years. If you have a machine that is 10 years
old, you may be able to get a replacement tubehead now, but if any other
component goes bad a year later you may find you cannot get parts for it.
Check into the history of the manufacturer to see if they still support
their older machines, and how far back that support typically goes. J Morita
still supports all its pans, even some that are over 30 years old, but that
is not always the case with other manufacturers. Also, don't forget that
when you replace a certified component - tubehead or otherwise - you are
required to have it registered (Form FDA 2579 - Report of Assembly of a
Diagnostic X-Ray System), recalibrated (internal resistances will vary
between tubeheads, and usually affect mA, but sometimes kVP will differ
also), and you may also have all your machines re-inspected, even the ones
that have not had components replaced. Make sure all your machines are
calibrated by the time you submit your paperwork.

 

I hope this is of help to you.

 

Paul Andrews

Equipment Division

J Morita USA

pandrews at jmoritausa.com <mailto:pandrews at jmoritausa.com> 

1-800-831-3222 x 1046

1-949-466-3916 (cell)

 

-----Original Message-----
From: Mansur Ahmad [mailto:ahmad005 at umn.edu] 
Sent: Friday, May 07, 2004 2:47 PM
To: 'Oral Radiology Discussion Group'
Subject: [Oradlist] Tube heads

 


Hello everybody:

Our school is planning to replace several x-ray tube heads.  If you have
recently purchased tube heads, would you please provide your
suggestions/opinions?  Instead of cluttering the list, you may want to write
to me directly at ahmad005 at umn.edu.

Thank you,

Mansur

================================
Mansur Ahmad, BDS, PhD
Asst Professor
Department of Diagnostic and Surgical Sciences
University of Minnesota School of Dentistry
7-536, Moos Health Sciences Tower
515 Delaware Street S.E.
Minneapolis, MN 55455

612-625-6147
Fax: 612-624-0477
ahmad005 at umn.edu




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