Ponente
Descripción
A precise determination of the dose locally delivered is of interest in multiple fields. In the case of radiotherapy, the measurement of the radiation dose ensures that the prescribed dose is properly delivered to the patient at the targeted location. Radiochromic films (RCFs) are currently the gold‒standard (passive) detectors for the measurement of dose distribution in radiology and radiotherapy. However, they are passive dosimeters, i.e., there is a considerable delay between irradiation and corresponding readout, and the subsequent evaluation of the dose delivered. In this context, the time-delay of the radiochromic films makes them an unfeasible tool for real-time daily dose evaluation. In response to these issues, we have proposed a new device based on a 2D-sensor that consists of a matrix of micro-opto-electro-mechanical (MOEM) elements [1] by using potential values of the system output as dose transducer. It consists of an optical sensor with light emitting diodes (LEDs) and an array of light-dependent resistors (LDRs) integrated in a fully tailored mechanical and electrical system including an in-house data analysis software and a graphical user-interface. A patent was filled in March 2021 [2]. Thanks to the high electronic versatility of our MOEM system, we may extend its scalable configuration to reach multiple sensitive spots, i.e. having high spatial resolution and covering large radiation areas, which is crucial for monitoring the dose.
The proposal is a new system based on a 5 × 10 matrix of photodetectors controlled by both in-house electronic circuit and graphical user interface (Figure 1). We present the first tests performed in an X-ray machine and 137Cs source with that array by using Gafchromic EBT3 films. We obtained similar results than with a standard method (e.g. flat-bed scanner). Results were compared with Monte Carlo simulations and very good agreement was found. Likewise, we have verified the proper performance of the MOEM sensor in a low-energy proton beamline at CNA (Seville). The outcomes demonstrate the viability of employing this technique for additional dose map assessment.
To the best of our knowledge, this is the first matrix of MOEMs as an active 2D sensing system for fast radiochromic film analysis. Further developments are ongoing to develop a portable dosimetry tool delivering dose maps in real time.
