'Magnitude' Searchterm 'Magnitude' found in 1 term [ • ] and 5 definitions [• ]Result Pages : • Magnitude
In physics, the magnitude (length) of a vector is a scalar in the physical sense, i.e. a physical quantity independent of the coordinate system, expressed as the product of a numerical value and a physical unit, not just a number. •
A vector is a quantity characterized by a magnitude (in mathematics a number, in physics a number times a unit) and a direction (and a point of application), often represented graphically by an arrow. The length of the line segment represents the magnitude, and its orientation in space represents its direction. Vector quantities can be added to or subtracted from one another. Used in diagnostic imaging to describe forces, e.g. magnetic moment, spin, magnetization etc.
• •
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 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. • Result Pages : |