26 Oct
2007
26 Oct
'07
1:59 a.m.
Philippe Vachon <philippe at cowpig.ca> wrote:
Being personally quite interested in DEC's
laboratory systems, I
stumbled a few days ago upon some scant details on DEC's nuclear medical
imaging system, the Gamma-11. Apparently this PDP-11 was designed to be
connected to a Gamma Camera, and had a VT11 or VSV11 display system
connected to it. As well, along with it came a modified version of
RT-11.
I was wondering if anyone on the list had one of these machines and knew
what parts made the hardware a Gamma-11, as well if anyone had manuals
online that they might share, as well as potentially the software for
the unit. There's not really much that I can see on Bitsavers, but I
might not have looked hard enough; I found the VSV11 and VT11 option
manuals, but that seemed to be about it.
Phil -
I have worked with many different medical scanners based around
PDP-11's. In every single case, they took a PDP-11 processor,
a Unibus or Q-bus backplane, some memory and a disk drive or two,
and bolted it onto an enormous kick-ass CAT scanner or NMR machine.
None of these were Gamma-11's.
Invariably the OS run was either RT-11 or RSX-11. With RSX-11
you usually had a custom device driver to talk to the specific
componentry but lots of time with RT-11SJ they just run around the
I/O page with what we'd call today "user code" with wild abandon.
So this doesn't help you find Gamma-11, but it does let you know
that for every Gamma-11 system out there, there were at least ten
or twenty other medical imaging systems that used -11's. I suspect
that some folks at DEC figured out that a lot of their systems were
being sold to put into medical imaging systems so they took some
common choices and put them into a catalog as a "starting point"
configuration, but real medical imaging vendors had specific needs so they just
specified what they needed and not what they didn't need.
For CAT scanners, the amount of computation needed to do the
backprojection usually resulted in a dedicated array processor
that spanned dozens of big boards and sucked up very large
amounts of power (often ECL). Well, that power sucking was not
really noticeable compared to all the X-ray guns :-)
The PDP-11 componentry pales in comparison to the backprojector
and table and stuff!
When I was working with these professionally, on a couple of
occasions the customer would offer to ship me an entire CAT scanner
for me to install in my basement at home. I never took them up on it!
Tim.