A six-bank multi-leaf system for high precision shaping of large fields.
In this study, we present the design for an alternative MLC system that allows high precision shaping of large fields. The MLC system consists of three layers of two opposing leaf banks. The layers are rotated 60 degrees relative to each other. The leaves in each bank have a standard width of 1 cm projected at the isocentre. Because of the symmetry of the collimator set-up it is expected that collimator rotation will not be required, thus simplifying the construction considerably. A 3D ray tracing computer program was developed in order to simulate the fluence profile for a given collimator and used to optimize the design and investigate its performance. The simulations show that a six-bank collimator will afford field shaping of fields of about 40 cm diameter with a precision comparable to that of existing mini MLCs with a leaf width of 4 mm.
Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. R.Topolnjak@azu.nl
R
R
Topolnjak
U A
UA
van der Heide
B W
BW
Raaymakers
A N T J
AN
Kotte
J
J
Welleweerd
J J W
JJ
Lagendijk
D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000379:methods*; D015233:Models, Statistical; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity