Why vertical patient positioning is more preferable for beam therapy than horizontal one?
The movement of internal organs during respiration makes a problem when it comes to increasing the accuracy of tumor irradiation. A patented method of compensation of internal organs movement is used in our system; however, any methods of compensation have limited accuracy. That is why the lower is the amplitude of the movement the higher is the accuracy of irradiation. We examined the movement amplitude of internal organs in the standing and lying positions of a patient. The results are given in the schemes below. It follows that in standing position the movement of internal organs is two times lower than in lying position. So, vertical patient positioning is more preferable.
Some doctors explain the advantage of horizontal patient positioning by the fact that diagnostic equipment functions the same way as in the lying position. To comment on this we can note that, firstly, our installation has a computer tomograph for vertical position integrated in the system; secondly, the growing demand for vertical tomographs will lead to their increased manufacture and production. There already exist some examples (www.p-cure.com). Thirdly, it is utterly irrational to take into account relatively cheap tomographs and bear enormous expenses producing gantries and rooms for them as well e t.c. these are economical arguments though.
The fixation system designed by us allows irradiating the patient in standing, sitting and lying positions. At the same time the cost of this system is ten times lower than the cost of a gantry. The necessary space for placing the proton therapeutic complex diminishes considerably when using our system of fixation and the required height of a building lessens from three floors to one.
It is known that the majority of doctors don’t even want to discuss treatment in vertical position. There exists a following dilemma:
Irradiating the patient in vertical position using comfortable fixation. This method is inappropriate for doctors because of lack of experience in this kind of irradiation. At the same time it is much more effective for the patient since the irradiation process takes several minutes.
Traditional method of treatment in lying position. For this treatment technology it is necessary to use gantries which increases the cost of installation and can be affordable only in rich hospitals (there were only 10 installations for proton therapy manufactured in one of the world’s richest countries in the last 20 years).
Actually, doctors offer to wait for decades until the hospital obtains the possibility to buy more expensive traditional equipment and when the patient himself collects enough money for a treatment session which is also quite costly.
Since our installation is cheaper than systems with gantry it may be widely manufactured and applied whereas more habitual for doctors system with gantry cannot become mass production.