Respiratory motion has been considered a clinical challenge for lung tumor treatments due to target motion. In this study, we aimed to perform an experimental evaluation based on dynamic phantoms using MLC-based beam tracking. TrackBeam, a prototype real-time beam tracking system, has been assembled and evaluated in our clinic. TrackBeam includes an orthogonal dual-layer micro multileaf collima...

Epithelioid hemangioendothelioma is a vascular tumor with an intermediate malignant potential. This tumor is very rare in the lung parenchyma, and most of the previously reported cases have been asymptomatic. There is no standard therapy for this tumor and prognosis in the previous reports has been variable.Herein we report our experience with a 60-year-old woman presenting with hemoptysis and ...

The purpose of this study was to investigate the accuracy of two-dimensional (2D) projection imaging methods in three-dimensional (3D) tumor motion monitoring. Many commercial linear accelerator types have projection imaging capabilities, and tumor motion monitoring is useful for motion inclusive, respiratory gated or tumor tracking strategies. Since 2D projection imaging is limited in its abil...

PURPOSE Respiratory motion presents significant challenges for accurate PET/CT. It often introduces apparent increase of lesion size, reduction of measured standardized uptake value (SUV), and the mismatch in PET/CT fusion images. In this study, we developed the motion freeze method to use 100% of the counts collected by recombining the counts acquired from all phases of gated PET data into a s...

During radiotherapy treatment for thoracic and abdomen cancers, for example, lung cancers, respiratory motion moves the target tumor and thus badly affects the accuracy of radiation dose delivery into the target. A real-time image-guided technique can be used to monitor such lung tumor motion for accurate dose delivery, but the system latency up to several hundred milliseconds for repositioning...

PURPOSE Respiration-induced motion artifacts in cone-beam CT (CBCT) can be corrected using a model of patient motion obtained from respiration-correlated CT (RCCT). This approach assumes that respiration-induced organ deformations at simulation, when RCCT scans are normally acquired, are still valid at treatment. The purpose of this study is to compare lung tumor image quality in motion-correct...

introduction radiotherapy with small fields is used widely in newly developed techniques. additionally, dose calculation accuracy of treatment planning systems in small fields plays a crucial role in treatment outcome. in the present study, dose calculation accuracy of two commercial treatment planning systems was evaluated against monte carlo method. materials and methods siemens once or linea...

Dear Editor, Several different approaches have been applied to stereotactic hypofractionated radiotherapy for lung tumors, including free breathing, breath-hold, gating, and tracking. Negoro et al. reported that abdominal compression reduced the movement of lung tumors (thereby possibly reducing treatment uncertainty), with portal fluoroscopy being used to measure the tumor movement [1]. Heinze...

Using fiducial markers on the patient's body surface to predict the tumor location is a widely used approach in lung cancer radiotherapy. The purpose of this work is to propose an algorithm that automatically identifies a sparse set of locations on the patient's surface with the optimal prediction power for the tumor motion. In our algorithm, it is assumed that there is a linear relationship be...

Due to respiratory motion, lung tumor can move up to several centimeters. If respiratory motion is not carefully considered during the radiation treatment planning, the highly conformal dose distribution with steep gradients could miss the target. To address this issue, the common strategy is to add a population-derived safety margin to the gross tumor volume (GTV). However, during a free breat...