Speaker
Description
Non-melanoma skin cancers (NMSC) account for nearly 96% of the worldwide diagnosed skin cancers and are often surgically removed. However, when surgery is not feasible, radiotherapy is a valid alternative treatment. In radiotherapy, patient-specific quality assurance (PSQA) relies on dose distribution measurements. Today the state-of-art technologies do not assure accurate measurements of the dose deposited in the superficial layers of the skin. The first few millimeters of skin are especially sensitive to ionizing radiation, and understanding dose distribution at these depths is essential to minimize adverse effects and to optimize the treatment effectiveness. In order to address this challenge, medical physicists frequently use a “bolus”, a semi-rigid material placed over the tumor to mimic tissue. Yet, as the tumor shrinks, air gaps may appear between fractions, leading to an underdosage of the prescribed treatment. To evaluate the air gap effect, a prototype detector (DQX) was designed and tested at the LPC[1] and CFB[2]. Based on a 100 μm thick plastic scintillator connected to wavelength shifting fibers, this device aims to measure radiation doses in the superficial layers of tissue, with a target relative measurement error below 1% for a 2 Gy photon dose, down to 70 μm below the skin surface.
In this presentation, an overview of the studies conducted on the DQX detector prototype is presented, describing in detail the experiments carried out and the preliminary results obtained. We also explore the detector design, its performance, limitations, and advantages, as well as perspectives for future developments in this field.
1 Laboratoire de Physique Corpusculaire de Caen, France
2 Centre François Baclesse, Caen, France
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