A feasible method for clinical delivery verification and dose reconstruction in tomotherapy

Abstract

Delivery verification is the process in which the energy fluence delivered during a treatment is verified. This verified energy fluence can be used in conjunction with an image in the treatment position to reconstruct the full three-dimensional dose deposited. A method for delivery verification that utilizes a measured database of detector signal is described in this work. This database is a function of two parameters, radiological path-length and detector-to-phantom distance, both of which are computed from a CT image taken at the time of delivery. Such a database was generated and used to perform delivery verification and dose reconstruction. Two experiments were conducted: a simulated prostate delivery on an inhomogeneous abdominal phantom, and a nasopharyngeal delivery on a dog cadaver. For both cases, it was found that the verified fluence and dose results using the database approach agreed very well with those using previously developed and proven techniques. Delivery verification with a measured database and CT image at the time of treatment is an accurate procedure for tomotherapy. The database eliminates the need for any patient-specific, pre-or post-treatment measurements. Moreover, such an approach creates an opportunity for accurate, real-time delivery verification and dose reconstruction given fast image reconstruction and dose computation tools.

Tomoterapia helicoidal: IMRT adaptada guiada por imagen

“…En una situación ideal, si la anatomía del paciente no cambia, los parámetros de colocación e inmovilización del paciente no varían y la radiación generada en el Acelerador Lineal es correcta, la reconstrucción de la dosis no sería necesaria; sin embargo, en condiciones clínicas, la reconstrucción de la dosis es de gran utilidad para determinar la dosis realmente administrada y compararla con la dosis planificada. De esta manera la tomoterapia, permite cuantificar e incluso corregir las discrepancias de dosis, asegurando un excelente control de calidad del tratamiento 16 .…”

A Review of intensity modulated radiation therapy: Incorporating a report on the seventh education workshop of the ACPSEM — ACT/NSW branch

“…The tomotherapy unit is specifically designed for the delivery of IMRT treatments. Listed amongst the advantages of a tomotherapy unit is the ability to perform close to real-time set-up verification, delivery verification and dose reconstruction [98][99][100] . The first clinical tomotherapy units are currently being installed in Canada and the United States.…”

Stability of the Helical TomoTherapy Hi·Art II detector for treatment beam irradiations

“…For example, 2D measurements may be carried out by electronic portal imager devices (EPIDs) (4) . Some 3D dose reconstructions methods were proposed, using the transit dose 5 , 6 , 7 , 8 , 9 , 10 . These techniques depend on the MVCT detector's short‐ and long‐term stability.…”