CT Downtime

How is "downtime" defined for our CT?

Canon (ex Toshiba) guarantees that the machine downtime does not exceed 2% per year. This is checked by calculating the ratio of yearly down-hours and yearly operating hours (2500 hrs/year, see TrueBeam). Nominal daily working hours are from 7:00 - 17:00. Typically, there is currently no patient after 14:00. In such a case, if the CT is down for a full day, we only record 7 hours (7:00 - 14:00).

Downtime Details AquilionLB

Date Hours Reason for Downtime
20.06.2011 7.5
21.06.2011 10.0
22.06.2011 5.0
2011 22.5 0.9%
29.11.2012 4.5 Tube replacement (scan counter old tube: 75000).
30.11.2012 7.0 Tube replacement (cont'd).
2012 11.5 0.5%
17.01.2013 1.0 Ring artefacts. Suspecting defective detector readout converter PWB.
18.01.2013 1.5 Ring artefacts again.
25.01.2013 2.5 Ring artefacts. Suspecting defective detector.
28.01.2013 5.5 Ring artefacts. Waiting for new detector.
29.01.2013 7.0 Installation of new detector.
25.04.2013 7.0 Reference detector failure.
26.04.2013 7.0 Installation of new reference detector. Still artefacts on images.
29.04.2013 7.0 Installation of new detector.
2013 38.5 1.5%
2014 0.0 0.0%
03.08.2015 7.0 Oil cooler replacement.
01.12.2015 7.0 Tube replacement (scan counter old tube: 130000).
2015 14.0 0.6%
2016 0.0 0.0%
2017 0.0 0.0%
2018 0.0 0.0%
24.01.2019 1.0 DICOM worklist doesn't work (device not connected or powered on). Checked cables, pinged w3454100, OK.
07.08.2019 3.0 Warm-up not possible. "X-Ray condition prohibited. Change scan condition". Replaced oil cooler.
2019 4.0 0.2%
14.04.2020 0.5 09:00: No couch movement. EM-off, rescued pat. After reboot, Vertical OK, horiz. not OK. Reboot again. OK.
20.04.2020 0.75 08:45: No longitudinal movement. Gantry OFF/ON, no change. Reboot, OK.
20.04.2020 0.42 11:42: No longitudinal movement. EM-off, rescued patient. Canon replaces touch guard in Gantry.
22.04.2020 1.5 12:30: No longitudinal movement. EM-off, rescued patient. Canon replaces drive assembly in couch.
2020 3.2 0.1%
18.05.2021 0.17 07:26: "Over kV" during warmup. Phantom test scan. Notified Canon.
01.06.2021 0.16 09:16: "Over kV" during warmup. Phantom test scan. Notified Canon.
02.06.2021 0.17 10:11: "Over kV" during warmup. Phantom test scan. Notified Canon.
08.06.2021 0.17 12:09: "Over kV" during warmup. Notified Physics.
09.06.2021 0.16 06:57: "Over kV" during warmup. Notified Physics & Canon.
22.06.2021 0.5 09:20: "Over kV" during patient scan. Scheduled tube replacement for tomorrow.
23.06.2021 7.0 Tube replacement. Still "Over kV". Troubleshooting.
24.06.2021 7.0 Waiting for parts.
25.06.2021 7.0 Troubleshooting cont'd.
2021 22.33 0.9%

back to Medical Physics home