ﻻ يوجد ملخص باللغة العربية
Purpose: Retinoblastoma (RB) is the most common eye tumor in childhood and can be treated external radiotherapy. The purpose of this work is to evaluate the adequacy of Monte Carlo simulations and the accuracy of a commercial treatment planning system by means of experimental measurements. Dose measurements in water were performed using a dedicated collimator. Methods: A 6MV Varian Clinac 2100 C/D and a dedicated collimator are used for RB treatment. The collimator conforms a D-shaped off-axis field whose irradiated area can be either 5.2 or 3.1cm$^2$. Depth dose distributions and lateral profiles were measured and compared with Monte Carlo simulations run with PENELOPE and with calculations performed with the analytical anisotropic algorithm (AAA) using the gamma test. Results: PENELOPE simulations agree well with the experimental data with discrepancies in the dose profiles less than 3mm of distance-to-agreement and 3% of dose. Discrepancies between the results of AAA and the experimental data reach 3mm and 6%. The agreement in the penumbra region between AAA and the experiment is noticeably worse than that between the latter and PENELOPE. The percentage of voxels passing the gamma test when comparing PENELOPE (AAA) and the experiment is on average 99% (93%) assuming a 3mm distance-to-agreement and a discrepancy of 3% of dose. Conclusions: Although the discrepancies between AAA and experimental results are noticeable, it is possible to consider this algorithm for routine treatment planning of RB patients, provided the limitations of the algorithm are known and taken into account by the medical physicist. Monte Carlo simulation is essential for knowing these limitations. Monte Carlo simulation is required for optimizing the treatment technique and the dedicated collimator.
Purpose: To investigate the validity of two Monte Carlo simulation absolute dosimetry approaches in the case of a small field dedicated `D-shaped collimator used for the retinoblastoma treatment with external photon beam radiotherapy. Methods: The
A broad-beam-delivery system for heavy-charged-particle radiotherapy often employs multiple collimators and a range-compensating filter, which potentially offer complex beam customization. In treatment planning, it is however difficult for a conventi
A model for beam customization with collimators and a range-compensating filter based on the phase-space theory for beam transport is presented for dose distribution calculation in treatment planning of radiotherapy with protons and heavier ions. Ind
Proton and carbon ion therapy is an emerging technique used for the treatment of solid cancers. The monitoring of the dose delivered during such treatments and the on-line knowledge of the Bragg peak position is still a matter of research. A possible
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