For example, if the side of a square pool is 10 yards, then the pool area is 10 x 10 100 square yards. Then simply multiply the measurement by itself to get the area. g is the difference between the reference SSD and the setup SSD. Since all sides are equal it does not matter which side is measured.The cutout factor is the ratio of output with the cutout placed in the applicator to the output of the applicator with no cutout in place.The applicator factor is the ratio of the the output with the utilized applicator to the output of with the reference applicator size (typically 10cm by 10cm).Note that only PDD is used in electron calculations.OAF is the off axis factor, taken to be 1 if calculation is made along the central axis.TF is the transmission factor, taken to be 1 if no trays or other devises are placed in the beam path.WF is the wedge factor, taken to be 1 if no wedge is used.For example, a physician may prescribe to the 90% isodose line in which case TT would be taken as 0.9.Although many prescriptions will simply define the prescription dose to be the 100% isodose lines, special cases (such as electron treatments and stereotactic radiosurgery) may not.TT is the treat to level, taken to be 1 if isodose line is not specified.S c and S p are the collimator and phantom scatter factors.Percent Depth Dose (PDD) is the method of choice for computing the required monitor units for non-isocentric techniques.Tissue Maximum Ratio (TMR) provides the simplest method for computing required in an isocentric technique.O is the output factor in units of cGy/MU.Rx is the prescription dose at the depth of interest (cGy).MU are the number of monitor units to be delivered.
0 kommentar(er)
