The Computed Tomography Exam is a comprehensive and wide-ranging assessment for men and women who want to enter this fast-paced and rewarding area of medical imaging. The exam consists of 185 multiple-choice questions and takes about four hours to complete. Twenty of the questions on the exam are pilot items, which are used to develop future versions of the test. These questions, impossible to identify, do not contribute to the final score.
The Computed Tomography Exam is divided into three content categories: patient care (31 questions); imaging procedures (76 questions); and physics and instrumentation (58 questions). The patient care content category covers five major issues: patient preparation, assessment and monitoring, IV procedures, contrast agents, and radiation safety and dosimetry.
The section on imaging procedures addresses studies of the head, neck, chest, abdomen, pelvis, and musculoskeletal system. Questions in this content category relate to sectional anatomy, contrast media, scanning procedures, and special procedures.
The physics and instrumentation section covers four major topics: CT system principles, operation, and components; image processing and display; image quality; and artifact recognition and reduction.
The Computed Tomography Exam is administered at testing centers around the country. In order to sit for the exam, candidates must present two forms of identification, one of which must be a valid, government-issued photo identification. Both forms of ID must include the candidate’s name and signature.
It usually takes about four weeks to score the exam. The raw score (number of questions answered correctly) is placed on a scale of 1 to 99. The relative difficulty of the test version influences the scaled score. The minimum passing score for the Computed Tomography Exam is 75. Typically, a candidate must answer 65 to 70 percent of the questions correctly in order to earn a scaled score of 75.
Computed Tomography Practice Test
1. Which of the following questions should be included in the pre-screening for a contrast CT exam on a 35 year old female?
a. Chance of pregnancy?
d. All of the Above
2. State law requires patients to sign consent forms in the following situations:
a. Prior to any injection of contrast materials
b. Prior to sedation for surgical procedures
c. Prior to hospital admission
d. Signed consent forms are not required by law in all states
3. Thorough patient preparation and education prior to a CT scan will do which of the following?
a. Reduce repeat radiation exposure
b. Reduce patient anxiety
c. Ensure best possible images
d. All of the above
4. What laboratory test(s) should be performed prior to CT exams that require IV contrast media injections to determine renal function?
a. Blood Urea Nitrogen (BUN) and Creatinine
b. Prothrombin Time (PT)
c. Platelet Count and Complete Blood Count (CBC)
d. Liver enzymes
5. What is considered a normal range for Blood Urea Nitrogen (BUN)?
a. 30-55 mg/dl
b. 0.6-1.7 mg/dl
c. 5-25 mg/dl
d. 155-190 mg/dl
Computed Tomography Answers
1. D: It is important to always ask women of child bearing age if there is any chance of pregnancy prior to any CT exam. If there is a chance, a pregnancy test needs to be negative prior to scanning the patient. All patients should be asked about allergies prior to a CT scan. The patient may have a latex allergy or a known IV contrast reaction history. Diabetes can affect a patient’s renal function, so lab work may be required prior to an IV contrast injection to make sure the kidneys can excrete the contrast from the blood. Also, certain diabetic medications also affect renal function. These medications may need to be stopped before and/or after IV contrast injections until renal function tests are performed. All these pre-screening questions should be asked again by the CT technologist immediately prior to the scan.
2. D: There are many variations of consent forms available that vary by state and by facility. Signed consent forms are required at some facilities prior to administering IV contrast during a CT scan. This is done to prove that the patient was informed about the risks and side effects and still agrees to have the contrast injection. There are currently no universal laws that mandate a signed informed consent.
3. D: Many patients are apprehensive about getting a CT scan. When a patient knows exactly what to expect they usually feel less anxious and are able to follow the scan instructions. Proper pre-scan preparations with oral prep, NPO instructions, and dress attire will minimize the risk for needing portions of the exam or even the entire procedure to be repeated thus reducing radiation dose to the patient and attaining the best possible images for that patient.
4. A: BUN and Creatinine levels indicate the ability of the patient’s renal systems to clear the contrast media from the blood. The BUN provides information about the ability of the kidneys to remove impurities from the blood. Elevated Creatinine levels indicate an impairment of the ability of the kidneys to excrete creatinine from the blood. Renal Disease impairs the ability of the kidneys to remove impurities from the blood. IV Contrast Media is considered an impurity and can cause a nephrotoxic effect in the patient. It is important to pre-screen most patients prior to administering IV contrast to ensure that they can clear the contrast from their blood.
5. C: Every facility interprets the normal range somewhat differently, but these are typical normal ranges. Urea is a waste product produced in the breakdown of protein in the liver, released in the bloodstream, filtered in the kidneys, and excreted in urine. When the kidneys are not properly working, there is a rise in blood urea nitrogen. Many other things can affect BUN levels such as certain medications, high protein foods, age, sex, dehydration, and pregnancy.