Anatomic Markers PDF

Anatomic Markers Basic marker conventions include the markers can be placed on the image elec- Anatomic Mark...

Anatomic Markers Basic marker conventions include the markers can be placed on the image elec- Anatomic Markers Each radiograph must include an appro- following: tronically at the computer workstation. priate marker that clearly identifies the The marker should never obscure This is not recommended because of the patient’s right (R) or left (L) side. Medi- anatomy. great potential for error and legal implica- colegal requirements mandate that these The marker should never be placed over tions; this is especially true when patients markers be present. Radiographers and the patient’s identification information. are examined in the prone position. Ana- physicians must see them to determine the The marker should always be placed on tomic markers should be placed on the CR correct side of the patient or the correct the edge of the collimation border. cassette or the DR table similar to screen- limb. Markers typically are made of lead The marker should always be placed film cassettes. Additionally, the practice of and are placed directly on the IR or table- outside of any lead shielding. placing markers directly on the body part top. The marker is seen on the image R and L markers must be used with CR is not recommended because the marker along with the anatomic part (Fig. 1-30). and DR digital imaging. is likely to be distorted on the image. This Writing the R or L by hand on a radio- The development of digital imaging will make side identification difficult, graph after processing is unacceptable. and the use of CR and DR have enabled thus defeating the purpose of using a The only exception may be for certain an environment in which the R and L marker. projections performed during surgical and trauma procedures. Box 1-3 presents the specific rules of marker placement. BOX 1-3 Specific marker placement recommendations 1. For AP and PA projections that include R and L sides of the body (head, spine, chest, abdomen, and pelvis), R marker is typically used. 2. For lateral projections of the head and trunk (head, spine, chest, abdomen, and pelvis), always mark the side closest to IR. If the left side is closest, use L marker. The marker is typically placed anterior to the anatomy. 3. For oblique projections that include R and L sides of the body (spine, chest, and abdomen), the side down, or nearest IR, is typically marked. For a right posterior oblique (RPO) position, mark R side. 4. For limb projections, use appropriate R or L marker. The marker must be placed within the edge of the collimated x-ray beam. 5. For limb projections that are done with two images on one IR, only one of the projections needs to be marked. 6. For limb projections where R and L sides are imaged side by side on one IR (e.g., R and L, AP knees), R and L markers must be used to identify the two sides clearly. 7. For AP, PA, or oblique chest projections, marker is placed on the upper-outer corner so that the thoracic anatomy is not obscured. 8. For decubitus positions of the chest and abdomen, R or L marker should always be placed on the side up (opposite the side laid on) and away from the anatomy of interest. Note: No matter which projection is performed, and no matter what position the patient is in, if R marker is used, it must be placed on the “right” side of the patient’s body. If L marker is used, it must be placed on the “left” side of the patient’s body. 27  SOURCE–TO–SKIN DISTANCE the most important aspect of producing an environment has prompted numerous Preliminary Steps in Radiography The distance between the focal spot of the optimal image. This is true regardless of technical problems in recent years because radiography tube and the skin of the the type of IR used. radiographers have collimated larger than patient is termed the source–to–skin dis- The area of the beam of radiation is the anatomic area in an effort to avoid tance (SSD) (see Fig. 1-34). This distance reduced to the required size by using a col- clipping anatomy, or they simply try to affects the dose to the patient and is limator or a specifically shaped diaphragm make their job easier. addressed by the National Council on constructed of lead or other metal with high It is a violation of the Code of Ethics to Radiation Protection (NCRP). Current radiation absorption capability, attached to collimate larger than the required field NCRP recommendations state that the the tube housing and placed between the size. When larger than the required area is SSD shall not be less than 12 inches tube and the patient. Because of the metal collimated, the patient receives unneces- (