Publicación: Comparación sistémica de la selección del medio de deposición de la dosis en tratamientos de Radioterapia
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2024-02-21
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info:eu-repo/semantics/openAccess
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Universidad Nacional de Educación a Distancia (España). Facultad de Ciencias
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Este estudio examina las discrepancias entre las distribuciones de dosis calculadas en agua (𝐷𝑤,𝑚) y en medio (𝐷𝑚,𝑚) con un algoritmo Monte Carlo en un sistema de planificación Monaco para tratamientos de radioterapia en patologías de pelvis, pulmón, vértebras y cabeza y cuello. Se analizan las diferencias en los índices dosimétricos de los órganos de riesgo y de los tumores según el cálculo en el medio elegido y normalizado al cálculo en agua, 𝐷𝑤,𝑚−𝐷𝑚,𝑚 𝐷𝑤,𝑚. Se obtienen variaciones en el volumen que recibe el 100% de la dosis prescrita (V100%) y en el volumen que recibe el 95% de la dosis prescrita (V95%) en los tratamientos de cabeza y cuello, de +11.4% (p-value<0.001) y +0.6% (p-value=0.002), respectivamente. En planes de vértebra y en planes de pulmón, los PTVs varían respectivamente +25.7% (p-value<0.001) en el V100% y -0.4% (p-value<0.001) en las dosis medias. En los órganos de riesgo, se observan variaciones del +11.1% (p-value=0.009) para el volumen que recibe 30 Gy de dosis prescrita y del +34.3% (p- value<0.001) para el volumen que recibe 40 Gy de la dosis prescrita en cabezas femorales y del 3.4% (p-value=0.002) y 3.6% (p-value<0.001) en dosis máximas en mandíbula y médula, respectivamente. Variaciones menores al -1% se observan en los pulmones, que se encuentran sobre-dosificados en el cálculo 𝐷𝑚,𝑚 respecto al 𝐷𝑤,𝑚. Se concluye que existen diferencias dosimétricas estadísticamente significativas entre medios de cálculo de dosis absorbida sobre todo en tumores u órganos de riesgo con densidades cercanas al hueso. Sin embargo, dada la incertidumbre del cálculo, del contorneo de los PTVs y órganos de riesgo, que los índices dosimétricos de los tratamientos se cumplen y tras compartir estos resultados con los oncólogos radioterápicos no se recomienda una revisión de estos índices ni de las prescripciones de dosis para tratamientos de pelvis, vértebras, pulmones y cabeza y cuello.
This study examines discrepancies between dose distributions calculated dose in water (𝐷𝑤,𝑚) and in tissue (𝐷𝑚,𝑚) using a Monte Carlo algorithm in a Monaco treatment planning system for radiotherapy treatments in pelvic, lung, spine, and head and neck pathologies. Differences in dosimetric indices of organs at risk and tumors are analyzed based on calculations in the selected medium and normalized to calculations in water, 𝐷𝑤,𝑚−𝐷𝑚,𝑚 𝐷𝑤,𝑚. Variations are obtained in the volume receiving 100% of the prescribed dose (V100%) and in the volume receiving 95% of the prescribed dose (V95%) in head and neck treatments, with increases of +11.4% (p-value<0.001) and +0.6% (p-value=0.002), respectively. In spine and lung plans, the PTVs vary by +25.7% (p-value<0.001) in V100% and -0.4% (p-value<0.001) in mean doses, respectively. For organs at risk, variations of +11.1% (p-value=0.009) are observed for the volume receiving 30 Gy of prescribed dose and +34.3% (p-value<0.001) for the volume receiving 40 Gy of prescribed dose in femoral heads, and 3.4% (p-value=0.002) and 3.6% (p-value<0.001) in maximum doses in the jaw and spinal cord, respectively. Minor variations below -1% are seen in the lungs, which are overdosed in the 𝐷𝑚,𝑚 calculation compared to 𝐷𝑤,𝑚 calculation. t is concluded that statistically significant dosimetric differences exist between calculation media for absorbed dose, especially in tumours or organs at risk with densities close to bone. However, given the uncertainty of the calculation, contouring of PTVs and organs at risk, and that dosimetric index of treatments are met, and after sharing these results with radiation oncologists, a review of these indices or dose prescriptions for pelvic, vertebral, lung, and head and neck treatments is not recommended.
This study examines discrepancies between dose distributions calculated dose in water (𝐷𝑤,𝑚) and in tissue (𝐷𝑚,𝑚) using a Monte Carlo algorithm in a Monaco treatment planning system for radiotherapy treatments in pelvic, lung, spine, and head and neck pathologies. Differences in dosimetric indices of organs at risk and tumors are analyzed based on calculations in the selected medium and normalized to calculations in water, 𝐷𝑤,𝑚−𝐷𝑚,𝑚 𝐷𝑤,𝑚. Variations are obtained in the volume receiving 100% of the prescribed dose (V100%) and in the volume receiving 95% of the prescribed dose (V95%) in head and neck treatments, with increases of +11.4% (p-value<0.001) and +0.6% (p-value=0.002), respectively. In spine and lung plans, the PTVs vary by +25.7% (p-value<0.001) in V100% and -0.4% (p-value<0.001) in mean doses, respectively. For organs at risk, variations of +11.1% (p-value=0.009) are observed for the volume receiving 30 Gy of prescribed dose and +34.3% (p-value<0.001) for the volume receiving 40 Gy of prescribed dose in femoral heads, and 3.4% (p-value=0.002) and 3.6% (p-value<0.001) in maximum doses in the jaw and spinal cord, respectively. Minor variations below -1% are seen in the lungs, which are overdosed in the 𝐷𝑚,𝑚 calculation compared to 𝐷𝑤,𝑚 calculation. t is concluded that statistically significant dosimetric differences exist between calculation media for absorbed dose, especially in tumours or organs at risk with densities close to bone. However, given the uncertainty of the calculation, contouring of PTVs and organs at risk, and that dosimetric index of treatments are met, and after sharing these results with radiation oncologists, a review of these indices or dose prescriptions for pelvic, vertebral, lung, and head and neck treatments is not recommended.
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Facultades y escuelas::Facultad de Ciencias
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Física Matemática y de Fluídos