Chapter 10: Formulating X-Ray Techniques

What is a human skeleton, or portion of a skeleton, encased in a plastic material that is similar in density to human tissue called?

Radiographic phantom

The use of the highest kVp setting that will produce sufficient contrast for acceptable image quality is called:

optimal kVp

The official organization that accredits hospitals and clinics, establishes standards for institutions that receive Medicare payments, and these standards include the requirements for x-ray technique charts in radiograph departments:

The Joint Commission

A technique chart based on an optimum kVp value set for each projection and the mAs is varied according to the patient/part thickness

Fixed kVp chart

A tool for body part measurement is called a(n):

Caliper

A listing of the various radiographic examinations performed in the facility

Technique chart

What is a device placed between the radiographic tube and the IR used to compensate for variations in tissue density called?

Compensating filter

A technique chart based on a specific mAs value for each projection and varies the kVp by 2 to 3 kVp/cm for changes in patient/part size.

Variable kVp chart

Which of the following, if changed permanently, would require a change in the technique chart?

1. kVp

2. mA

3. SID

All 3

A listing of the various radiographic examinations performed in a radiographic room along with the exposure factors is called a(n):

Technique chart

Which of the following methods are effective ways to obtain a technique chart?

1. Create one using a Supertech® calculator.

2. Request assistance from the equipment manufacturer’s technical representative.

3. Hire a radiographer consultant who is experienced in technique chart preparation.

All 3

Technique charts are based on patient body part measurements obtained using an x-ray caliper. These measurements are expressed as

Part thickness in centimeters

What is the name of the organization that requires technique charts be posted for every radiographic room?

The Joint Commission

Technique charts are based on:

Thickness of the body part to be radiographed

Which type of technique chart has a specific mAs value for each projection and uses small changes in kVp to compensate for variances in patient or part size?

Variable kVp

Using the principle of “optimum kilovoltage” to formulate exposure techniques will result in ___________ patient exposure and _______ exposure latitude.

the least; wide

How does one determine if the mA station is obtainable at the desired kVp without exceeding the capacity of the x-ray tube?

Consult the tube rating chart

A good reason for sometimes selecting the highest available mA station to obtain a given amount of mAs is to:

Keep the exposure time as short as possible

What is the correct exposure time required to produce 50 mAs when using the 200 mA station?

0.25 seconds

How much of a change in mAs is needed if there is a 2-cm increase in the part size?

30%

A satisfactory radiograph is made using 20 mAs at 40 inches SID. How much mAs is needed to produce a similar radiograph at 60 inches SID?

45 mAs

Advantages of using a fixed kVp technique chart include which of the following?

1. Contrast is lower.

2. Exposures will have more latitude.

3. Patient exposures are lower.

2 and 3 only

Which technical factor should be used to correct problems with radiographic density?

mAs

Which of the following pathologic conditions require a decrease in exposure technique?

1. Multiple myeloma

2. Emphysema

3. Osteoporosis

All 3

Which technical factor is used to alter radiographic contrast?

kVp

Which radiographic quality characteristic is primarily affected by kVp?

Contrast

Which category of patient seldom requires a compensating filter for general radiographic examinations?

Pediatric

The minimum amount of mAs change that will prompt a visible change in image density is

30%

Which groups of patients need “specialized” technique charts?

1. Obese

2. Pediatric

3. Very muscular

1 and 2 only

What is the major limitation in obtaining images of obese patients?

Inadequate penetration of the body part

What is the single most important technical exposure adjustment that should be made when imaging an obese patient?

Increasing the kVp