Radiation systems & potential software problems? Didn't we learn from Therac:

[David Farber <dave () farber net>]

Begin forwarded message:

From: Harry Hochheiser <hshoch () gmail com>
Date: January 23, 2010 10:28:28 PM EST
To: dave () farber net
Subject: Radiation systems & potential software problems? Didn't we learn from Therac:

Dave:

For your consideration for IP, it seems that the lessons of the
Therac-25 have not really been learned.

It's obviously too hard to tell to what extent software design was a
major part of the problem, but the quotes given below seem to indicate
that that is a real possibility.

NY Times, January 23
THE RADIATION BOOM A Lifesaving Tool Turned Deadly
http://www.nytimes.com/2010/01/24/health/24radiation.html?hp

Fascinating article about difficulties with radiation delivery in oncology.


“Linear accelerators and treatment planning are enormously more
complex than 20 years ago,”
said Dr. Howard I. Amols, chief of clinical physics at Memorial
Sloan-Kettering Cancer Center in New York. But hospitals, he said, are
often too trusting of the new
computer systems and software, relying on them as if they had been
tested over time, when in fact they have not."
..
"Shortly after 11 a.m., as Ms. Kalach was trying to save her work, the
computer began seizing up, displaying an error message. The hospital
would later say that similar system crashes “are not uncommon with the
Varian software, and these issues have been communicated to
Varian on numerous occasions.”
.....
"The investigation into what happened to Mr. Jerome-Parks quickly
turned to the Varian software that powered the linear accelerator.

The software required that three essential programming instructions be
saved in sequence: first, the quantity or dose of radiation in the
beam; then a digital image of the treatment area; and finally,
instructions that guide the multileaf collimator.

When the computer kept crashing, Ms. Kalach, the medical physicist,
did not realize that her instructions for the collimator had not been
saved, state records show. She proceeded as though the problem had
been fixed."

-Harry Hochheiser




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