CT Introduction Flashcards
Who discovered x-rays?
Wilhelm Conrad Röntgen
In what year was x-rays discovered?
1895
A type of “shadow” of all the dense tissues in the path of the x-ray beam as it passes through the patient
Conventional Radiograph
Who is deemed as “father” of CT releasing the first commercial CT scanner in the early 1970s?
Godfrey Newbold Hounsfield
Every CT scanner must include a source of x-rays, called _____, and at least one x-ray _____
CT X-ray Tube / Detector
First-generation scanners had an x-ray tube that produced what kind of beam?
Pencil Beam
For first-generation scanners, its beam passes through the patient to how many detectors?
One
How many degrees did the first-generation scanners rotated by?
1 degree
What was the total scan time of first-generation scanners per image?
5 minutes
Second-generation scanners had an x-ray tube that produced what kind of beam?
Fan Beam
For second-generation scanners, its beam passes through the patient to how many detectors?
Multiple detectors in a straight line
How many degrees did the second-generation scanners rotated by?
5 degrees
What was the total scan time of second-generation scanners per image?
20 seconds
Third-generation scanners had an x-ray tube that produced what kind of beam?
Fan Beam
For third-generation scanners, its beam passes through the patient to how many detectors?
Multiple detectors in an arc
What was the total scan time of third-generation scanners per image?
Less than 1 second
What is the main difference when it comes to fourth-generation scanners compared to the previous generations?
Multiple detectors encircles the patient, but only the tube rotates around the patient
What are the benefits of multi-row detector CT scanners?
Faster scan
Increased anatomical coverage
Resolution improvement
Why would a cone beam CT be used in the oncology department?
To verify patient positioning prior to receiving radiation therapy
What are the benefits of CT?
Cross-sectional
Tissue differentiation
Digital
Speed
What are the three conventional imaging planes?
Transverse
Coronal
Sagittal
What are some benefits to digital information?
Easily stored on a computer
Always accurately reproduced from the stored data
Easily & quickly manipulated and processed on a computer
Can be stored on optical disk or CD
Can be electronically transported to remove viewing facilities
“Throughput” refers to…
The number of patients one can scan in a given period of time
Repeated exposure to ionizing radiation can result in…
Malignancies and birth defects
What are some common indications for CT when looking at the head?
Viewing facial bones
Study the sinuses
What are some common indications for CT when looking at the chest?
Infection
Cancer
Pulmonary emboli
Aneurysms
What are some common indications for CT when looking at the abdomen?
Cysts Abscesses Infection Bleeding Tumors Aneurysms Diverticulitis Appendicitis
What are some common indications for CT when looking at the urinary tract?
Detect kidney stones
Blockages
Abnormal growths
What are some common indications for CT in reference to an orthopedic?
Trauma
Evaluate extent of damage
What is the target in the CT x-ray tube made of, and why?
Tungsten:
High atomic number = efficient x-ray production due to its many electrons
High melting point = prevents target from heating up when electrons hit
