ESTRO 2024 - Abstract Book

S3659

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2024

Results:

Figure 1 shows the results obtained in the ring.

1. For D 2% and D 10% the increase of the value of "a" implies a reduction of high doses up to 10%. No significant differences appear for values of a>20. Therefore, this value is adequate if high dose reduction outside the PTV and organs in series is desired. 2. The lowest mean dose value is obtained for a=10, with a difference of 4-5% with respect to the rest of the values of "a". This value would be adequate to optimize organs in parallel. Even improving the optimization of a=1 (equivalent to the mean dose). Table 2 shows the results referred to PTV. As "a" increases its value it is seen that the D 95% dose decreases (with differences of up to 5%), thus losing coverage. These differences are not seen for D 98% and D 2% where the variations are less than 1%.

If the value of "a" is fixed and the histogram is analyzed for different separations of the auxiliary ring, it is observed that a ring very close to the PTV can compromise its coverage.

Finally, no significant changes appear in the results by varying the dose per fraction.

Conclusion: