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RAD141-Chap 7c
RAD141-Chap 7c - AP & Lateral Weight-bearing projections - foot
| Question | Answer |
|---|---|
| Why used? | to check the arches of the foot under the full weight of body |
| Which projection demonstrates which arch? | the lateral projection demonstrates the longitudinal arch; the AP demonstrates the horizontal arch |
| What is an additional consideration for laterals? | both feet are usually take for comparison (separately) |
| What IR size s/b used? | 8 x 10 or 10 x 12 |
| Should a detail screen be used? | yes |
| What is the proper kV range? | 65 +/- 5 kV |
| Is shielding appropriate? | yes - gonadal |
| What is the patient position for the AP weight-bearing projection? | patient stands erect, full weight evenly distributed on both feet; feet directed straight ahead, parallel to each other |
| What is the CR position for the AP? | book says that the CR is angled 15 deg posteriorly to midpoint between feet at level of base of metatarsals |
| How should the patient be positioned for a lateral weight-bearing projection? | patient stands erect, weight evenly distributed, standing on wood blocks placed on a step stool or footrest (provide support for patient to hold onto); support vertical cassette between feet, with long axis of foot to long axis of IR |
| How should the patient be positioned for the 2nd foot in a lateral weight-bearing foot? | change cassettes and turn patient for lateral of other foot for comparison after 1st lateral is taken |
| What is the CR position for the lateral? | directed horizontally to level of base of third metatarsal |
| What is the radiographic criteria for AP? | projection show soft tissue surrounding phalanges to distal portion of talus; open tarsometatarsal joint spaces and visualization of the joint between 1st & 2nd cuneiforms; metatarsal bases s/b at center of collimated field |
| What is the radiographic criteria for structures shown and positioning for the lateral? | entire foot and min 1 inch of distal tibia-fibula (distal fibula should not be superimposed over posterior half of the tibia and plantar surfaces of heads of metatarsals should appear directly superimposed) |