Combination of Fixed port and Rotational port
Let°«s think about the merits of combination fixed port and rotational port. To simplify, the dose distributions of one fixed port and rotational port are made at °∆virtual water phantom°« for one direction.
As you know, the width of isodose line of fixed port is narrowing slightly at isocenter. Meanwhile, the width of isodose line of rotational port is narrowing at incident point. Combination of both ports show even width from incident point and isocenter.
Next, we make air density part involved each beams (this mean lung tissue). In fixed port, isodose line shows marked deformity. Of course, the isodose line of rotational port shows deformity, but it seems a little compare with that of fixed port. Unfortunately, the isodose line are shown as oblique angle. If combine these ports, the isodose line at isocenter lies more verticality.
last modification date: 2009/10/01