CT scanner was made up of only two x-ray detectors, which were located on the opposite side of the patient from where the x-ray tube was situated.

They demonstrate the feasibility of functional marriage of detector-source assembly.

CT scanners that is very powerful in terms of reduction of scatter reduction.

This is considered a demonstration project.

Rotate/Translate narrow Fan Beam.

CT scanner involved an x-ray fan beam with an angle ranging between 40 to 60 degrees.

This scanner used a pinhole collimator to ensure only a single beam of x-rays was interacting with the patient.

CT scanner with the incorporation of a narrow fan x-ray beam with an angle of approximately 10 degrees resulting in a linear array of 30 detectors.

This scanners evolved in which the x-ray tube and the detector array were rotated concentrically around the patient.

This generation CT has new array consisted of 400 to 1000 detector elements.

Radiation detection is accomplished through a fixed circular array of detectors which contains 1000-2000 individual element.

This produces characteristic image artifacts known as ring artifacts.

This uses curvilinear array containing many detectors and a fan beam.

CT scanners that are said to operate using a rotate-stationary geometry.

CT scanner is composed of no moving parts.

Generation scanner have a rotate only motion.

Generation scanner that the x-ray tube can rotate either outside or inside the detector ring.

CT scanners were developed specifically for use in cardiac tomography imaging.

These unit are capable of 1 second scanning time can accommodate variable slice thickness through automatic pre patient collimation and can provide image manipulation capabilities of earlier scanners.

Known as helical CT.

CT scanner consists of a multiple detector array and a cone shaped x-ray beam.

An Australian mathematician who proved that an image of 3 dimensional objects can be produced

1^st CT scan machine

He proposed a method to represent a single slice of the body on the radiographic film. (TOPOGRAPHY).

Refers to a method of obtaining sectional views of the body that eliminates x-ray shadows of body structures before and behind the desired

Time between the end of imaging and the appearance of an image.

It refers to movement of source-detector assembly across the patient; - Results in a projection

A selectable scan factor based on the Hounsfield scale

Area of information on reconstructed image that does not exist in reality

An intensity profile

Television screen use to display CT image and to communicate withy computer

The motion of the x-ray tube and radiation detection system required to collect data for reconstructing CT images

Computer programs that controls CT system

Hardware

Software

Scan

Scan image

Cross sectional thickness of the body parts that is scanned for generating CT images.

Basic elements that defines the volume of a tissue that each pixel represents in a reconstructed image.

This is the x-ray tube and radiation detection system that measures the amount of radiation passing through the patient.

Frameworks that holds the x-ray tube and detection system

Two dimentional picture element that makes up the matrix. Each pixel represents a CT number is thebuilding block of the matrix and image.

This indicates that a series of images is then combined into a single 3 dimentional image by computer means.

The following are the major systems of CT, EXCEPT?

The following are purposes of the imaging system, EXCEPT?

These are part of the operator's area.

This is a part of the electronic room.

The following are major components of CT, EXCEPT?

This is a component of the imaging system, EXCEPT?

The heat capacity of the x-ray tube in CT.

The generator supplies power to the following, EXCEPT?

This maintain the width of the beam as it travels toward the patient.

This protects patient from low energy photons.

The following are function of filtration system, EXCEPT?

provides a beam closer to mono-energetic

provides a more uniform beam

* Restrict the filed of exposure

Protects patient from low energy photons

This collect attenuated photon energy and convert it to electrical signal, which will then be converted to a digital signal for computer reconstruction.

The path that an x-ray beam travels from tube to a single detector.

A complete set of ray sums.

This refers to the method by which the patient is scanned to obtain enough data for image reconstruction.

Scan technique that utilizes a continuous rotating gantry and data acquisition system at a rate of one rotation per second.

The following are advantages of pitch detector, EXCEPT?

The following are disadvantages of pitch detectors, EXCEPT?

This is usually with one breath hold and obtain a volume of X-rayed tissue while the table moves rapidly through the gantry.

The following are advantages of dynamic scan, EXCEPT?

Known as localized scan.

The time required for slice to be scanned, reconstructed, displayed and filmed.

The time of actual exposure per slice.

This is done to avoid any mis-registration due to difference in the 1st and last tube position.

The following are events that will occur when x-ray hits an object. EXCEPT?

The following are patient based artifacts, except?

The following are examples of helical and multichannel artifacts, except?

These are examples of hardware based artifacts, except?

This is an example of MPR artifacts

This is an example of physics based artifacts

This is the phenomenon that occurs when an x-ray beam comprised of polychromatic energies passes through an object, resulting in selective attenuation of lower energy photons

This artifact appears as multiple dark streaking bands positioned between two dense objects, for example at the posterior fossa

This information that is not part of a desired signal, is present in all electronic systems, and originates from a number of sources including electronic interference

This occurs when tissues of widely different absorption are encompassed on the same CT voxel producing a beam attenuation proportional to the average value of these tissues

Refers to an error in the accuracy proponent of analog to digital converter (ADC) during image digitization

This is one source of streak artifact which may occur in CT and it is seen in high attenuation areas, particularly behind metal implants

This depends on the number of discrete x-ray photons reaching the detector

This occurs when there is a short-circuit within the tube, typically from the cathode to the tube envelope

This is due to the presence of abdominal gas in the oil coolant which surrounds the x-ray tube

This is due to part of the patient existing peripheral to the field of view of the CT scanner

CT phenomenon that occurs due to mis-calibration or failure of one or more detector elements in a T scanner

They occur close to the isocenter of the scan and are usually visible on multiple slices at the same location they are a common problem in cranial CT.

This is an image distortion in the axial plane, encountered during helical multidetector acquisitions.

This appear as alternating bright and dark bands in a MRI image.

This is caused by inadequate data sampling in the z-plane, due to multiple detector rows intersecting the reconstruction plane during each rotation of the gantry.

Contrast-enhanced ultrasound with microbubbles is used in the assessment of: EXCEPT:

These conditions could affect the instructions you are given, EXCEPT?

The following are mild side effects of Ba Sulfate, EXCEPT?

You are at greater risk of an adverse reaction to barium sulfate contrast materials if?

Mild reactions includes the following, EXCEPT?

Moderate reactions include the following, EXCEPT?

Severe reactions include?

Manufacturers of intravenous contrast provide special instructions for mothers who are breast feeding, they advise that mothers should not breast-feed their babies for _______ hours after contrast medium is given

When an iodine based contrast material is is injected into your bloodstream you may have the following, EXCEPT?

These are conditions that may increase risk of CIN, EXCEPT?

It is a good idea to increase your fluid intake after an imaging exam involving an iodine-based contrast material to help improved the contrast material from your body

If you are sedated, no recovery period is necessary

Many imaging tests and contrast material administrations are done during pregnancy to minimize risk to the baby

If the mother remains concerned about any potential ill effects, she should be given, the opportunity to make an informed decision as to whether t continue or temporarily abstain from breast-feeding after receiving a gadolinium contrast medium

Contrast materials are dyes that permanently discolor internal organs

The thicker the slice the better the resolution but the worse the noise

Thinner slices increase the partial volume effects

Thin slices allow isotropic scanning

Isotropic scanning improved volume rendering

Z-sensitivity refers to the effective imaged slice width

The wider (in the z-axis) the detector row, the higher the resolution

A broad focal spot improves the z-sensitivity

Acquiring the data using overlapping slices can improve z-sensitivity

To improve spatial frequency we can decrease the matrix size

Larger number of projections gives finer resolution

Lower resolution kernels do not average out high spatial frequency signals and therefore produce more noise

Higher resolution or “sharp” kernels (e.g. bone reconstruction) have better spatial resolution than soft kernels (e.g. soft tissue reconstruction)

Smaller detectors give higher resolution but more detectors within an area also means more partitions (dead space) and a reduced overall detection efficiency

If the position of the focal spot moves in the X-Y plane, then the in-plane resolution increases.

Smaller focal spots give higher resolution, but the max mA is limited to prevent damage to anode

The term slice refers to the number of rows of detectors in the z-axis of a CT

The limitation with using a SSCT was that the thinner slices requiring high image-quality were not achievable unless the region to be scanned was very restricted, leading to low-quality images.

The first scanner with more than one row of detectors was introduced by Elscint in 1992 and was called the CT-Twin

The first “modern” versions of MSCT scanners were developed and introduced in 1998 and simultaneously acquired 4 slices

With technologies such as automatic exposure control (AEC) and iterative reconstruction (IR), a patient scanned on a higher slice CT will receive significantly lower doses of radiation than a patient on a lower dose CT scanner.

The following are other names for CT, EXCEPT?

Indicates a series of cross sectional x-ray images made along a chosen body axis.​

     process of energy absorption or scattering , describe by the percent of radiation remaining after x-rays passes through object.​

The following are storage requirement for CT, EXCEPT?

A transaxial/transverse image

has a dynamic range of 12 bits (4096 gray levels)

Computer-adapted mathematical calculation applied to raw data during image reconstruction .

Creation of an image from raw data.

the year when Haunsfield first demonstrated the CT technique.

the year when first clinical CT scanners were installed.

  Hounsfield & Allan Mcleod Cormack shared the Nobel Prize in Physics

the year when CT scan machine became widely available.

1^st CT system that could make images of any part of the body .

Plane of the image is parallel to the long axis of the body

  Plane of image is perpendicular to the long axis of the body

The electron beam tomography CT

To scan the patient, the patient table is moved through the gantry aperture.

__________ is the angle between the vertical plane, and the plane containing the x-ray beam and the detector array.

___________ _allows aligning the selected anatomic region with the scanning plane.

_________ is the opening through which the table with the patient moves for the examination.

Typical diameters of the gantry range fom ______ cm.

The antry aperture diameters between ______ cm are useful for obese patients.

The anode heating capacity must be at least _______

CT tubes may produce 30 exposures per examination and most CT units maybe scheduled 10-20 examination per day or around 10,000 examinations per month.

Focal spot size is relatively unimportant in most design since the scanner is not based on the principle of direct geometry.

    Pulsed beam at tube current approaching to _______

  Early CT scanner employed one detector , Contemporary scanners use multiple detectors in an array from 10-1000.

   Converts x-ray energy into light.

Convert x-ray energy directly into electrical signal.

___________ is how well the detectors received photons from the patient. It is controlled primarily by the detector size and distance between them.

__________ is how well the detector converts incoming x-ray photon. It is determined by the materials used( Kind of crystal and gas ) as well as the size and thickness of the detector.

____________is how well the detectors converts absorbed photons information to a digital signal.

___________    refers to the steadiness of the detector response, it is controlled by how often the detectors must be recalibrated to meet the quality control standard.

________     is the speed with which the detector can react to recognized an incoming photons and recover from the next.

__________ is the ratio of the largest signal that can be measured to the smallest to be discriminated.

attenuation measurement of each ray

uses a crystal that fluoresces when struck by x-ray photon which produces light energy

attached to scintillation portion, transforms light energy into electrical or analog energy

converts the analog signal from the detector into a digital signal

      to convert physical parameters to electrical signals.

•      , to convert sensor signals into a form that can be converted to digital values.

     to convert conditioned sensor signals to digital values.

The following are physics based artifacts, EXCEPT?

The following are hard-ware based artifacts, EXCEPT?

The following are examples of Helical and multichannel artifact, EXCEPT?

The following are examples of MPR artifacts, EXCEPT?

     The acquisition of a single image per breath hold.

acquisition of a group or cluster of rapid scan during a single breath hold. Patient breath in between cluster, this reduces acquisition time

   Minimize mis-registration of targeted anatomy that cam occur when patients hold breath for every scan.

time required for slice to be scanned, reconstructed, displayed and filmed.

patient/table moves through the gantry. A localized scan.

time from the end of one exposure/scan to the start of the next exposure/scan . Table incrementation occurs during this delay.

time from the start of one scan to the start of the next.

is due to the different tissue in the body having different attenuation values.

    definition of scanning area and how many points of data will be acquired.

•      is the diameter of area to be scanned.

the process where in image is created by reflecting attenuation  profiles in the same direction they are obtained.

•      a mathematical filter function which eliminates star/streaking patterns that result in back-projection.

manipulation of the raw data to construct an image using different display FOV or algorithm. This can be done if the data is still available.

reconstruction of only a portion /segment of the entire scan. This can be used to try to eliminate a portion of the scan where motion may have occurred.

the removal of star artifacts from surgical clips or other metal objects.

creation of an image in a different orthogonal plane.