ESTRO 2024 - Abstract Book

S3249

Physics - Detectors, dose measurement and phantoms

ESTRO 2024

Phases

Static (cGy)

Moving (cGy)

Difference (%)

1

248.95

248.20

0.30

2

247.95

247.21

0.30

3

287.01

286.27

0.26

4

285.01

285.27

-0.09

6

284.02

285.01

-0.35

8

285.77

285.27

0.17

The radiochromic films have been compared with each other with a gamma analysis of 3% 1mm, 2% 1mm and 1% 1mm with a threshold of 10%, yielding a gamma of 3% 1mm >99% for 3 phases and a gamma of 3% 1mm >95% for 6 phases (figure 2).

Figure 2: Gamma analysis with EBT3 radiochromic films of 1, 3 and 6 phases of the respiratory cycle.

As shown in figure 2, the gamma analysis of the different phases of the respiratory cycle shows a result of 3% 1 mm > 95%, however the best results were obtained for the 3-phase treatment.

For few phases tratments, the ITV generated is smaller, helping to better preserve organs at risk. However, this requires a longer treatment time in the accelerator, which could be a drawback in the actual treatment of patients.

Conclusion:

In this work it has been verified that the irradiation of a treatment with gating in the accelerator versus a continuous treatment corresponding to a treatment without respiratory control introduces a difference in the delivered dose due