المدينة الطبية · مختبر الأجهزة · الجهاز 4 من 69
جهاز التصوير المقطعي المحوسب
CT Scanner
جهاز التصوير المقطعي المحوسب في مختبر الأجهزة في المدينة الطبية من BMEssentia. افتحه بتقنية ثلاثية الأبعاد تفاعلية، وفكّكه قطعةً قطعة، وتعرّف إلى طريقة عمله، ثم تعلّمه على منصة BMEssentia واسأل إسنشيا عنه.
محتوى مختبر الأجهزة في هذه الصفحة باللغة الإنجليزية، كما هو داخل المدينة الطبية.
- عدد الأجزاء: 10
- عدد التكوينات في مختبر الأجهزة: 2
- يُعرف أيضًا باسم: Computed Tomography, Cat Scan
مختبر الأجهزة
CT Scanner
A general-purpose diagnostic scanner. The bore is kept small because it puts the patient nearer the isocentre, which is where the geometry of the measurement is best.
التكوينات
نسخ الجهاز في مختبر الأجهزة.
64-slice diagnostic CT
A general-purpose diagnostic scanner. The bore is kept small because it puts the patient nearer the isocentre, which is where the geometry of the measurement is best.
Wide-bore CT simulator
A planning scanner for radiotherapy. It gives up bore economy so that a patient can be scanned in the position they will be treated in, with their immobilisation around them.
كيف يعمل
استكشفه في مختبر الأجهزة.
Dose and noise are the same dial
Halve the tube current and watch two numbers move. The dose halves, exactly, because dose is linear in the number of photons. The noise rises by about forty per cent, because noise falls as the square root of the photons counted.
The control that changes dose without looking like it
5 and the scan finishes a third sooner. Two other things happen at the same time and neither is announced: the dose falls by a third and the noise rises.
Kilovoltage is not a brightness control
Move the kilovoltage from 120 to 140 and the dose rises by about half as much again. Move it down to 80 and it falls to about a third. 7, which is far steeper than anyone expects from a setting that looks linear.
A resource with a refill rate
Run a demanding protocol back to back and watch the tube heat climb. It falls between studies, but by less than each study adds, so the line drifts upward through the session until the machine stops.
Where the couch is, is where the slice is
Change the pitch, the collimation and the rotation time and watch the table speed, which is pitch times collimation divided by rotation time. Then watch the scan time, which is simply the length divided by that speed.
الأجزاء
قطعةً قطعة.
Gantry covers and front bezel
The white cabinet with a hole through it. Everything the patient sees of this machine is a cover, and none of it does any imaging.
Patient aperture
The tunnel itself, lined and lit, wide enough for a person and not much more. The whole design of the machine is a negotiation about how big this is allowed to be.
Gantry control panels
Two small panels set into the front of the machine, either side of the aperture, where a radiographer standing with the patient can reach them without walking anywhere.
Gantry status display
A small screen high on the front of the machine, visible from the control room door. It is the only part of the scanner that tells you what it is doing from across the room.
Stationary frame and base
The steel structure under the covers that everything else is bolted to, and the feet that transfer all of it into the building.
Internal alignment lasers
Three small windows inside the aperture, throwing thin lines of light onto the patient. They are how a person is put where the machine thinks they are.
Rotating gantry
The ring inside the covers that carries the whole imaging chain and turns it around the patient, two to four times a second, continuously, for as long as the machine is scanning.
Slip ring
Concentric conductive tracks on the back face of the rotor, with brushes riding on them from the stationary frame. It is the reason a CT scanner can rotate indefinitely.
Rotation drive
A motor on the stationary frame and a belt around the rotor. It accelerates about a tonne of assembly to three revolutions a second and holds it there precisely.
X-ray tube
The heaviest single object on the rotor, and the only thing on the machine that makes X-rays. Everything else either shapes what it produces or measures what survives the patient.
المحاكاة
أين يظهر في المحاكاة.
ملاحظات الطُّرز
طُرز حقيقية، بعد المراجعة.
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