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Flashcards in Final exam Deck (194)
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151

Chest radiographs if taken AP rather than PA at 72 inches will cause:

increased magnification of the heart shadow.

152

Placing heart closer to film for PA projection results in:

less magnification.

153

Goal of evaluation criteria:

Optimal radiograph.

154

What is evaluation criteria?

Definable standard so every chest radiograph can be evaluated.

155

Signs of rotation in a PA projection:

Clavicles will not be equidistant from the spine. Whichever clavicle is closest to the spine is the direction of the rotation.

156

Sufficient neck extension ensures:

chin will not superimpose upper lung region.

157

Patients with large pendulous breasts should be asked:

to pull the breasts upward and laterally. Have the patient hold the breasts in place by leaning against the IR.

158

For a lateral chest position, place the side of interest:

Closest to the IR.

159

For routine lateral chest postioning:

Left side is closest to the IR.

160

The separation of posterior ribs resulting from beam divergence at 72 inches should only be (what distance?)

1/4 to 1/2 inches or about 1 centimeter.

161

Direction of rotation on a lateral can be determined by identifying:

the gastric air bubble in stomach or by ID'ing inferior border of heart shadow. Both are associated with the left hemidiaphragm.

162

Tilt on a lateral chest X-ray would be demonstrated by:

closed intervertebral disk spaces.

163

Why are arms raised high during a lateral chest X-ray?

To prevent superimposition of the humerus and soft tissue of humerus on the upper chest field.

164

What two bony landmarks can provide a consistent and reliable means of determining CR location for chest X-ray?

Vertebra prominens and jugular notch.

165

CR chest positioning method: verterbra prominens corresponds to:

Level of T1 and uppermost margin of apex of lungs.

166

After palpating the vertebra prominens:

Measure 7 inches down for females, 8 inches down for males to determine proper CR location.

167

Exceptions to positioning the CR at T7:

Larger, athletic females may have longer lung fields, and some males may have shorter lung fields. Some well-developed athletic sthenic/hyposthenic type men require centering closer to T8 or 9 inches down from vertebra prominent.

168

The level of T7 on average adults is --------below the jugular notch.

3-4 inches

169

The level of T7 on older or hypersthenic patients is:

3 inches below the jugular notch.

170

The level of T7 on younger or on sthenic/hyposthenic athletic types is:

4-5 inches below the jugular notch.

171

IR placement depending on lung dimensions (AP or PA projections):`

Tech determines whether the IR should be placed lengthwise or crosswise based on body habitus. Apices to costophrenic angles must be included.

172

Digital chest units may include larger IR's. True or false?

True. This eliminates the crosswise vs lengthwise concern.

173

It is recommended that most AP recumbent chest X-rays are done:

crosswise, due to an increased chance that the side of chest would be "clipped" with lengthwise IR.

174

PA chest collimation guidelines:

Adjust field margins to outer skin margins, remembering that the chest expands during inspiration. Adjust the upper border of the illuminated field to the vertebra prominens.

175

Digital Imaging Considerations.
Collimation:

*reduces dose
*ensures optimal quality of processed image by reducing scattered radiation from reaching CR or CR IR's
Alows computer to provide accurate information regarding exposure index number.

176

Digital Imaging Considerations.
Accurate centering:

Because of the technique used by the CR or DR image receptor, it is important that the body part and CR be accurately centered to the IR.

177

Digital Imaging Considerations.
Exposure factors:

Digital imaging systems are known for their wide exposure latitude; they are able to process an acceptable image from a broad range of exposure factors (kV and mAs). Radiation protection: ALARA; use highest kV with lowest mAs consistent with optimal image quality.

178

Digital Imaging Considerations.
Post-processing evaluation of exposure index:

Once the image is available for viewing, the image will be critiqued for positioning and exposure accuracy.
The tech must check the exposure index number to verify that the exposure factors used were in the correct range to ensure optimum quality with the least radiation to the patient.

179

Alternative modalities or procedures.
Conventional and computed tomography:

Conventional tomography used to be used for locating lesions found on chest films, but CT is frequently used for such purposes.

180

Alternative modalities or procedures.
Bronchography:

Radiologic procedure where contrast media was introduced into bronchial tree to rule out certain pathologies. Bronchography has ben replaced by different imaging procedures including CT.