A tomographic imaging direction, backwards relative to a short axis of the human body from the front to the back.

A tomographic imaging direction, frontwards relative to a short axis of the human body from the back to the front.

See also Anterior Posterior, Left Anterior Oblique, Right Anterior Oblique, Annotation, Antegrade.

A bone scan or bone scintigraphy is used to in evaluate diseases of the skeletal system. Scintigraphic whole body bone imaging is a highly sensitive method to show changes in bone metabolism. Increased metabolic activity is seen as a hot spot.
The study requires the injection of a 99mTc-labeled radiopharmaceutical (most commonly methylene diphosphonate (MDP), hydroxymethylene diphosphonate (HMDP) or hydroxyethylene diphosphonate (HDP)). The activity administered for bone scanning is around 500 MBq (300-1100 MBq, 8-30 mCi), depending on age and weight of the patient. After 2-5 hours, the emitted gamma rays are detected by gamma cameras. The produced planar images include anterior and posterior views of the skeleton.
Multiphase bone scintigraphy is used to differentiate a bone process from tissue pathology. In some cases additional SPECT imaging is helpful to better characterize the presence, location and extent of disease.

A tomographic imaging plane, perpendicular to the ground, the coronal plane separates the anterior from the posterior part (the front from the back).

If available, some graphic aids can be helpful to show image orientations.
1) A graphic icon of the labeled primary axes (A, L, H) with relative lengths given by direction sines and system of coordinates as if viewed from the normal to the image plane can help orient the viewer, both to identify image plane orientation and to indicate possible in plane rotation.
2) In graphic prescription of obliques from other images, a sample original image with an overlaid line or set of lines indicating the intersection of the original and oblique image planes can help orient the viewer. The location in the R/L and P/A directions can be specified relative to the axis of the scanner.
The F/H location can be specified relative to a convenient patient structure.
The orientation of single oblique slices can be specified by rotating a slice in one of the basic orientations toward one of the other two basic orthogonal planes about an axis defined by the intersection of the 2 planes.
Double oblique slices can be specified as the result of tipping a single oblique plane toward the remaining basic orientation plane, about an axis defined by the intersection of the oblique plane and the remaining basic plane. In double oblique angulations, the first rotation is chosen about the vertical image axis and the second about the (new) horizontal axis. Angles are chosen to have magnitudes less than 90° (for single oblique slices less than 45°); the sign of the angle is taken to be positive when the rotation brings positive axes closer together.