1 Introduction

The new features of modern photon radiotherapy treatments force the treatment planning system (TPS) calculations to be far from reference conditions. Then, calculated dose map distribution may differ from the real one [1]. These treatments generally include dose escalation in the vicinity of critical organs that should be spared, so it is understood the importance of dose calculation accuracy. Thus, additional test are required to verify this.

2 Material and method

The system [2] consists of a rotating cylindrical polyethylene phantom that houses the dual single-sided silicon strip detector (DSSSSD), that is two singled-sided silicon strip detectors positioned so that the strips of each one are perpendicular to the other. The active area of the DSSSSD is placed centred in an axial plane of the phantom, parallel in general to the beam incidence direction. Each strip works as an independent detector that is previously calibrated in dose to water. The experimental data set contains statistical uncertainties, that are taken into account by means of using reconstruction methods based on statistical estimation techniques. The issue consists on obtaining the mean absorbed dose in a grid of pixels, treating them like parameters included in the probability density function of the experimental data. Bayesian methods, as maximum a posteriori, provide an iterative solution in which prior information can be added to improve the results.

3 Results

The proposed method is applied to a theoretical treatment plan that consists of three fields pointing to a position outside the cylinder center. Reconstructed dose map of treatments show a good agreement with TPS calculated ones (Fig. 7.1).

Fig. 7.1
figure 1

Dose profile of 2D treatment reconstructed map and comparison with the TPS calculation

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