Question 1

A patient enters the ED with severe trauma to the abdomen.The ED physician is concerned about bleeding in the abdomen with associated possible free intra-abdominal air.The patient is unable to stand or sit erect.Which position best demonstrates the condition?

Accepted Answer

Lateral decubitus position is best for evaluating free intra-abdominal air by using a left lateral position to allow air to rise to the highest point in the abdomen. This will increase the sensitivity of air detection on X-ray imaging.

Question 2

A radiographer receives 400 mR/hr standing 1 foot from a C-arm fluoroscopy unit.What is the exposure rate if the radiographer moves to a distance of 3 feet?

Accepted Answer

According to the inverse square law, the exposure rate decreases as the distance from the source increases. The equation for this law is I1/I2 = (D2/D1)^2, where I1 is the initial exposure rate (400 mR/hr), I2 is the exposure rate at the new distance, D1 is the initial distance (1 foot), and D2 is the new distance (3 feet). Solving for I2, we get I2 = I1 * (D1/D2)^2 = 400 * (1/3)^2 = 44.44 mR/hr, which is within the range of 25 to 50 mR/hr given in choice C. Therefore, the correct answer is C.

Question 3

Postreduction projections of the upper and lower limbs generally require only the joint nearest to the fracture site.

Accepted Answer

Postreduction projections of the upper and lower limbs generally require only the joint nearest to the fracture site, as the focus is on the area of the bone that has been fractured and the adjacent joint.

Question 4

What is the minimum distance a technologist should stand away from the x-ray tube during an exposure when using a mobile x-ray unit?

Accepted Answer

A technologist should stand at least 6 feet away from the x-ray tube during an exposure when using a mobile x-ray unit to minimize radiation exposure.

Question 5

A patient enters the ED with a possible fractured sternum.The patient is supine and unable to lie prone.Which of the following routines best demonstrates the sternum?

Accepted Answer

The LPO position allows for the sternum to be projected over the heart shadow, providing better contrast and visibility. The horizontal beam lateral is used when the patient cannot be positioned upright, ensuring a lateral view of the sternum.

Question 6

How should the CR be aligned for a trauma PA projection of the elbow?

Accepted Answer

The CR should be perpendicular to the interepicondylar plane for a trauma PA projection of the elbow. This helps to ensure that the radial head, neck, and tuberosity are demonstrated clearly.

Question 7

How much rotation is required for an AP oblique projection of the sternum on a hypersthenic patient?

Accepted Answer

The answer of How much rotation is required for an...

Question 8

A patient enters the ED with a possible shoulder dislocation.Because of his multiple injuries,the patient is unable to stand or sit erect.Which of the following routines best demonstrates the dislocation?

Accepted Answer

The answer of A patient enters the ED with a...

Question 9

A patient comes to the ED with a possible abdominal aortic aneurysm.Which of the following projections of the abdomen best demonstrates it?

Accepted Answer

A dorsal decubitus projection is best for demonstrating an abdominal aortic aneurysm, as it allows for visualization of the entire aorta without superimposition of other structures. The erect abdomen may not provide adequate visualization, and the lateral decubitus and KUB projections may have superimposition or limited visualization of the aorta.

Question 10

What is the primary disadvantage of performing a PA thumb over an AP projection?

Accepted Answer

The primary disadvantage of performing a Posteroanterior (PA) thumb over an Anteroposterior (AP) projection is that it results in an increase in object image receptor distance (OID). This can lead to a decrease in image sharpness due to increased magnification and potential distortion of the thumb's anatomy.

Question 11

Which of the following positions or projections best demonstrates free intra-abdominal air on the patient who cannot stand or sit erect?

Accepted Answer

The left lateral decubitus position is best for demonstrating free intra-abdominal air because the air will float and collect under the right diaphragm, making it visible on an X-ray. This position allows the air to rise above the liver and collect under the diaphragm, increasing the visibility on the X-ray. The other positions may not show the air as clearly or may require the patient to be able to stand or sit up.

Question 12

A patient enters the emergency department (ED)with a possible pneumothorax of the right lung.The patient is unable to stand or sit erect.Which specific position should be performed to diagnose this condition?

Accepted Answer

The left lateral decubitus position is the best choice for diagnosing a possible pneumothorax of the right lung. This position allows the air to rise to the uppermost part of the thorax, making it easier to detect any abnormal pockets of air. In addition, the patient's weight is not resting on the affected side, which can cause discomfort or compromise the diagnostic findings.

Question 13

A 30° tilt of the C-arm x-ray tube from the vertical position will increase radiation exposure to the face and neck region of the operator standing next to the C-arm by approximately a factor of:

Accepted Answer

A 30° tilt of the C-arm x-ray tube from the vertical position will increase radiation exposure to the face and neck region of the operator standing next to the C-arm by approximately a factor of 4. This is due to the increased scatter radiation that occurs when the x-ray tube is not perpendicular to the patient's body.

Question 14

Which one of the three cardinal rules of radiation protection is the most effective means of reducing exposure during mobile and surgical procedures?

Accepted Answer

Distance is the most effective means of reducing exposure during mobile and surgical procedures because radiation exposure decreases rapidly with distance. In contrast, time and shielding may be less effective in these situations as they may not always be practical or feasible.

Question 15

What type of "holding breath" instructions should be given for an AP projection (patient supine)of the ribs located above the diaphragm?

Accepted Answer

For an AP projection of the ribs above the diaphragm, the exposure should be made upon inspiration to elevate the diaphragm and provide a clearer view of the ribs.

Question 16

Which of the C-arm orientations in general results in the greatest exposure to the operator's head region if the distance from the patient is unchanged (patient is supine)?

Accepted Answer

The anteroposterior (AP) projection results in the greatest exposure to the operator's head region because the x-ray tube is above the anatomy, which leads to more scattered radiation in the direction of the operator's head.

Question 17

How should the CR be aligned for an AP projection of the chest?

Accepted Answer

The CR should be perpendicular to the long axis of the sternum for an AP projection of the chest. This will ensure proper visualization of the heart and lungs.

Question 18

A self-propelled,battery-driven mobile x-ray unit will generally go up a maximum incline of:

Accepted Answer

A self-propelled, battery-driven mobile x-ray unit is typically designed to handle inclines up to 7°. This limitation is due to the balance between power, safety, and the ability to navigate hospital corridors and ramps without compromising stability or battery life.

Question 19

Where should the operator (or surgeon)stand when using a C-arm fluoroscopy unit in a horizontal central ray (CR)position?

Accepted Answer

The operator should stand at the intensifier end of the C-arm to minimize radiation exposure, as the intensity of scattered radiation is significantly lower on this side compared to the x-ray tube side.

Question 20

A patient enters the ED with a fractured forearm.The physician reduces the fracture and places a fiberglass cast on the forearm.The initial analog technique was 55 kV and 5 mAs.Which of the following technical factors is best for the postreduction study?

Accepted Answer