Simulation on the motion error of dynamic tumors on the accuracy of the treatment plan in proton-therapies

Background: In proton-therapies, the ultimate goal is to create a uniformly distributed 3D dose distribution within the volume of the tumor, so that the dose reaches the healthy tissue around the tumor is minimized, but typically in tumors located in the chest region Depending on the movement and shape of the target volume (tumor), the dose achieved with the prescribed dose will not be appropriate.Methods: Our aim in this study is to obtain a quantitative assessment of the 3D dose distribution on moving or deformed tumors and surrounding tissue surrounding respiratory movements. To accomplish this, a simulation study was carried out using the Monte Carlo Fluke code. The Fluke code is a multi-functional computational code for calculating particle transport and interactions between them and matter based on the Monte Carlo method. It is very useful in tracking heavy charged particles in a well-applied field and in the field of hadron therapy. In this study, the simulation of a proton-therapeutic center with an inactive diagnostic method was conducted to evaluate the distribution of doses in fixed, deformed, and mobile tumors.Results: In this study, the results of simulation on different tumors with different movements with a constant tumor status were compared to estimate the tumor movement error in the dose distribution. Also, the effect of deformation of the tumor has been studied for different states. In order to improve the results of the dose distribution in tumors that were mobilized and transformed, a discriminatory diagnostic method at the end of the respiratory period was used to reduce the amount of stored doses in the healthy tissue significantly in different situations.Conclusion: At the time of tumor deformation and movement, if the target area is considered to be the entire PTV region, the prescribed dose will be left in the total volume of the tumor, but a large volume of healthy tissue will also dose a dose of about a maximum dose Will receive. In order to improve the dose distribution in this study, non-continuous diagnostic techniques with modifications to inactive devices have been used, in view of the type of movement and tumor deformation, to reduce the dose to the healthy tissue surrounding the tumor. Significantly decreases, and the dose distribution to the steady-state tumor is very close

کلیدواژه ها:

Mediastinum ، Lymphoma ، Proton beam therapy