COMPUTED
TOMOGRAPHY
An X-ray sees through you. A CT scanner sees around you. Follow a beam from its source to the cross-sections that reveal a hidden world.
SCROLL TO BEGIN ↓ONE MACHINE.
THREE SYSTEMS.
The gantry holds the imaging system. The table moves the patient through its opening. Inside, a source and detector turn together: one sends, one measures.
GANTRY · TABLE · ROTATIONUNDER
THE SHELL
The calm exterior hides a coordinated machine. Peel back the housing to find the rotating ring, X-ray tube, and curved detector array.
ASSEMBLY / EXPLODEDTHE ROTATING
GANTRY
One view flattens depth. Turn the source and detector around the patient, and overlapping structures leave different signatures at each angle.
360° ACQUISITIONX-RAY
SOURCE
A fan-shaped beam spreads from the tube toward the detector. As the ring turns, the beam traces new paths through the same anatomy.
X-RAYS VISUALIZED · ROTATION SLOWEDTHROUGH
THE BODY
Every path leaves a signature. Air lets more X-rays through; bone lets fewer through. The detector measures what remains after the whole journey.
I = I₀ e^(−μx)MEASURED
IN LIGHT
In the illustrated detector, a scintillator turns incoming X-rays into light. Electronics convert that light into a digital measurement for each channel.
DETECTOR ARRAYONE ANGLE.
ONE PROJECTION.
One angle gives one profile across the detector. Repeat around the body and the profiles change. Together, those views constrain what can be inside.
0° · 45° · 90° · 135° · 180°DATA
IN MOTION
Stack the profiles by angle. A structure traces a curved path as its position shifts across the detector. This sinogram is organized measurement data, not yet anatomy.
DETECTOR POSITION × ACQUISITION ANGLEFROM SIGNAL
TO 3D VOLUME
Reconstruction combines measurements from many directions to estimate each cross-section. These synthetic slices reveal the same body, lung regions, and spine shown during acquisition.
SYNTHETIC ANATOMY · RECONSTRUCTION ILLUSTRATEDEVERY PART.
ONE PICTURE.
A source, a detector, a moving table, and reconstruction software. Each has a different job. Together, they turn invisible paths into a view inside.
SCROLL ON TO EXPLORE EACH SYSTEMEXPLORE THE
SCANNER
Drag to rotate. Scroll to zoom. Select a component to zoom in and expand its explanation.
The protective enclosure surrounding the rotating imaging system.
The housing separates the patient space from the moving machinery. Its central opening, or bore, lets the table pass through while the source and detector rotate inside.
A high-speed ring carries the source and detector around the patient.
The ring keeps the source and detector aligned on opposite sides of the patient. Each angle contributes another projection, giving reconstruction measurements from many directions.
A compact, cooled tube produces a fan-shaped beam of X-rays.
The tube sends a fan-shaped beam through the body toward the detector. Different paths lose different amounts of intensity, encoding information about the tissues along each path.
Segmented detector cells measure the transmitted X-ray intensity.
Each channel records the X-rays that reach it. In this illustrated detector, a scintillator converts X-rays to light before electronics turn that light into a digital signal.
The motorized table positions the patient precisely through the bore.
Controlled table motion positions the anatomy within the imaging plane. Moving it along the bore lets the scanner sample successive cross-sections of the object.