- Fracture and/or dislocations of the phalages of the digits in question are demonstrated. Some pathologies, such as osteoarthritis and gouty arthritis (gout), may be evident, especially in the first digit.
Technical Factors:
- IR size - 18 x 24 cm (8 x 10 inches), crosswise
- Divide in thirds, crosswise
- Detail screen, tabletop
- Digital IR - use lead masking
- 50 to 60 kV range
Note:
- Some departmental routines include centering and collimation for the AP toes to include all the toes and distal metatasals. Most involved centering to the toe of interest with closer collimation to include only one digit on each side of injury.
Shielding:
Patient Position:
- Take radiograph with patient supine or seated on table; knee should be flexed with plantar surface of foot resting on cassette.
Part Position:
- Center and align long axis of digit(s) to CR and long axis of portion of IR being exposed.
- Ensure that MTP joint(s) of digit(s) in question is (are) centered to CR.
Central Ray:
- Angle CR 10 to 15 degree toward calcaneus (CR perpendicular to phalanges).
- If a 15degree wedge is placed under the foot for parallel part-film alignment, then the CR is perpendicular to the IR.
- Center CR to MTP joint(s) in question.
- Minimum SID is 40 inches (100 cm).
Collimation:
- Collimate on four sides to area of interest. On side margins, include a minimum of at least part of one digit on each side of the digit(s) in question.
CR or DR:
- Close collimation and lead masking are important over unused portions of image plate to prevent fogging from scatter radiation to the hypersensitive image plate or receptor.
Radiographic Criteria:
Structure Shown:
- Digit(s) of interest and a minimum of the distal half of metatasals should be included.
Part Position:
- Individual digits should be separated with no overlapping of soft tissue.
- Long axis of foot aligned to long, axis of portion of IR being exposed.
- No rotation is present if the shafts of the phalanges and distal metatarsals appear equally concave on both sides. Rotation will appear as one side being more concave than the other. The side with increased concavity has been rolled away from the IR.
AP toes, with wedge (CR perpendicular) |
Collimation and CR:
- Collimation borders should be visible on all four sides with the center (CR) at the MTP joints(s) of interest with at least the distal half of metatasals included.
Exposure Criteria: