| Revista: | Revista mexicana de física |
| Base de datos: | PERIÓDICA |
| Número de sistema: | 000447369 |
| ISSN: | 0035-001X |
| Autors: | Querebalú Garcia, C1 Carrasco Solis, E1 Valladolid Salazar, J2 Centeno Ramos, J3 |
| Institucions: | 1Instituto Nacional de Enfermedades Neoplásicas, Lima. Perú 2Universidad Nacional de Ingeniería, Lima. Perú 3Universidad Nacional Mayor de San Marcos, Lima. Perú |
| Any: | 2021 |
| Període: | Nov-Dic |
| Volum: | 67 |
| Número: | 6 |
| País: | México |
| Idioma: | Inglés |
| Tipo de documento: | Artículo |
| Enfoque: | Analítico, teórico |
| Resumen en inglés | Volumetric modulated arc radiotherapy treatments (VMAT) can achieve highly conformed dose distributions however, due to the complexity of the technique, there may have differences between the planned and administered dose distributions, generated by the precision in the dose calculation of the treatment planning system (TPS) or by the errors associated with it. One way to quantify the difference between both dose distributions is by using the gamma index; however, there is no accord regarding the parameters that should be used in its analysis. On the other hand, this gamma index may depend on the pathology and the area to be treated. For this reason, the present work aims to evaluate different parameters of the analysis of the gamma index for breast cancer treatments; these are local and global normalization, the analysis criteria (1%/1 mm, 2%/2 mm, 3%/2 mm, 2%/3 mm, 3%/3 mm and 5%/3 mm), and the low dose threshold (LDT) of 5% and 10%. For this, 30 treatment plans performed with VMAT technique in a 6 MV Infinity linear accelerator (Elekta, Stockholm, Sweden) were analyzed, calculated with the TPS Monaco V.5.11.03 (Elekta, Stockholm, Sweden) and measured with the Octavius 4D system (PTW, Freiburg, Germany). The results of the analysis of the global gamma index were of a gamma passing rate (%GP) greater than 95% for analysis criteria of 3%/3 mm and 5%/3 mm; however, for these same parameters in the local gamma index analysis, the results are 85.8% and 91.1% respectively. In addition, from the LDT evaluation, it is observed that there is a mean increase of %GP for the local gamma index analysis and a mean decrease of %GP for the global gamma index analysis, for the LDT from 5% to 10%. On the other hand, the standard deviation is lower in the global gamma index; analysis than in the local one, and it decreases when the analysis criteria are less strict. It is concluded that there is not a great difference in choosing the LDT of 5% or 10%. When the gamma analy |
| Disciplines | Física y astronomía |
| Paraules clau: | Pacientes, Indice Gamma, VMAT, Umbral de dosis inferior, Criterio de análisis, Control de calidad |
| Keyword: | Patients, Gamma index, VMAT, Lower dose threshold, Analysis criteria, Quality control |
| Text complet: | Texto completo (Ver HTML) Texto completo (Ver PDF) |
