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A cobalt machine killed a patient just a few days ago, in Voronezh, Russia. The patient was crushed between the movable treatment table and the collimator. As

A cobalt machine killed a patient just a few days ago, in Voronezh, Russia. The patient was crushed between the movable treatment table and the collimator. As far as I can tell from the limited information available on the web, the problem was not software but rather a stuck manual switch. Sorry for linking the daily fail, but the only articles I can find in English seem to be in UK tabloids: https://www.dailymail.co.uk/news/article-7066289/Cancer-patient-crushed-death-malfunctioning-radiation-treatment-machine-Russian-hospital.html https://www.dailymail.co.uk/news/article-7066289/Cancer-pati... по-русски: https://dni.ru/regions/2019/5/23/424405.html https://dni.ru/regions/2019/5/23/424405.html

wolf550e 7y ago
That's kinda like being killed by jacked up car crushing person working on the car underneath. Nothing to do with radiation or software. With a static device where operator does not position the jack, the cause would be lack of mechanical maintenance or material failure (unlikely).
- jschwartzi 7y ago
  The failure mode of the switch contributed to this accident, and a switch which does not exhibit this failure mode should have been used if possible. If not possible, then the switch should have been moved through a test actuation before reaching a position where the failure mode causes the patient to be killed. This test actuation should be performed each time the table is moved. Finally, the pathway that the switch passes through should be periodically cleared of debris and the switch tested on a regular basis. If the test actuation fails(indicating switch failure) then the table should reset to a safe position. As an aside, every time I step on the treadmill at the gym I check that the emergency stop button works and that the incline down and speed down buttons work. I have been stuck on a treadmill which I couldn't stop or slow down before.
  - ryacko 7y ago
    That is what the sides of the treadmill are for.
  - jdsully 7y ago
    All mechanical devices will fail eventually. While a test actuation might reduce the risk somewhat - its not going to be a sure thing. Remember the table didn't kill the last patient that stepped on it - why would anyone suspect the switch would fail now. Mechanical failures need to be dealt with differently than software. Parts must be replaced before they fail. Even if they appear to work correctly. Software doesn't wear out so its a whole different ball game.
trhway 7y ago
another source with machine photo: https://moe-online.ru/news/incidents/1036835 https://moe-online.ru/news/incidents/1036835 Sounds like there is an obvious design failure - similar to garage or elevator doors the table shouldn't move and push up beyond some force threshold (patient weight plus say 200N of force).

wolf550e 7y ago

That's kinda like being killed by jacked up car crushing person working on the car underneath. Nothing to do with radiation or software. With a static device where operator does not position the jack, the cause would be lack of mechanical maintenance or material failure (unlikely).

jschwartzi 7y ago
The failure mode of the switch contributed to this accident, and a switch which does not exhibit this failure mode should have been used if possible. If not possible, then the switch should have been moved through a test actuation before reaching a position where the failure mode causes the patient to be killed. This test actuation should be performed each time the table is moved. Finally, the pathway that the switch passes through should be periodically cleared of debris and the switch tested on a regular basis. If the test actuation fails(indicating switch failure) then the table should reset to a safe position. As an aside, every time I step on the treadmill at the gym I check that the emergency stop button works and that the incline down and speed down buttons work. I have been stuck on a treadmill which I couldn't stop or slow down before.
- ryacko 7y ago
  That is what the sides of the treadmill are for.
- jdsully 7y ago
  All mechanical devices will fail eventually. While a test actuation might reduce the risk somewhat - its not going to be a sure thing. Remember the table didn't kill the last patient that stepped on it - why would anyone suspect the switch would fail now. Mechanical failures need to be dealt with differently than software. Parts must be replaced before they fail. Even if they appear to work correctly. Software doesn't wear out so its a whole different ball game.

trhway 7y ago

another source with machine photo: https://moe-online.ru/news/incidents/1036835 https://moe-online.ru/news/incidents/1036835 Sounds like there is an obvious design failure - similar to garage or elevator doors the table shouldn't move and push up beyond some force threshold (patient weight plus say 200N of force).