Why should you angle the gantry when scanning CT of the brain?
To reduce the amount of radiation to the eyes, brain CT scans are often made with a tilted gantry.
Where should the head be centered in CT?
PATIENT POSITIONING: • Patient should be supine, head first into the gantry, with the head in the head-holder whenever possible. Center the table height such that the external auditory meatus (EAM) is at the center of the gantry.
What is gantry in CT scan?
The gantry of a computed tomography scanner (CT) is a ring or cylinder, into which a patient is placed. The x-ray tube and x-ray detector spin rapidly in the gantry, as the patient is moved in and out of the gantry. The CT scanner produces 3-dimensional x-ray images of the patient.
How do I prepare for a sinus CT scan?
CT Sinus with IV Contrast: Do not eat anything for 4 hours before the exam. Drink only clear liquids, such as plain jello, tea, fruit drinks without pulp, black coffee and water. If you are over 60, diabetic or have high blood pressure, a blood test is needed before your scan. (See Exams That Require Contrast).
What is the difference between axial and helical CT scan?
Helical scanning has continuous data usage so that the detector data is used in a ‘sliding window’ manner. Compared with axial where the neighboring slabs use separate data which is more susceptible to motion between the slabs.
How is CT scan of brain done?
During a brain CT, the X-ray beam moves in a circle around the body, allowing many different views of the brain. The X-ray information is sent to a computer that interprets the X-ray data and displays it in a two-dimensional (2D) form on a monitor.
Does CT scan of head show sinuses?
Most CT scans of the head do not include all the sinuses. A CT scan with contrast may be ordered for people with strokes, hydrocephalus, or certain growths.
What is the gantry angle?
The actual gantry angle could then be defined as the angle between vertical, as indicated by a plumb bob, and the direction of the beam axis that could be indicated by the position of a BB placed in the central axis and its shadow.
What are the parts of CT gantry?
The CT imaging system includes the moveable gantry and patient table or couch. The gantry is a frame that contains the x-ray source, collimators, filters, detectors, a data acquisition system (DAS), rotational components including slip ring systems and all associated electronics.
How does helical CT work?
With helical CT, the patient is moved through a rotating x-ray beam and detector set. From the perspective of the patient, the x-ray beam from the CT traces a helical path. The helical path results in a three-dimensional data set, which can then be reconstructed into sequential images for a stack.