[Determination of source position for four radiography systems with orthogonal projections in brachytherapy].
Four configurations of two X-ray tube positions are available for determining the position of a point using two orthogonal films. For each configuration, there are many formulas for calculating the coordinate of a point: the least squares methods with and without physical meaning, such as six sets of geometrical solutions, an approximation method with constant magnifications and so on. It is troublesome for a person in charge of treatment planning to directly derive a formula or select an appropriate formula from numerous ones for the four configurations. Thus, a method to easily apply the published formula for a configuration to the other three configurations is described in simulations and a clinical case using rotation matrixes of the right-handed coordinate system. Each diagonal element of the rotation matrixes is 1 or -1, and the other elements are 0.
Tabushi
K
K
Department of Radiotherapy, Saitama Cancer Center.
Itoh
S
S
Sakura
M
M
Kato
S
S
Kazumoto
T
T
Nakamura
Y
Y
Iinuma
T A
TA
Arai
T
T
Irifune
T
T
D001918:Brachytherapy / Q000379:methods*; D003198:Computer Simulation; D005260:Female; D006801:Humans; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy