Systematic errors specific to a snapshot Mueller matrix polarimeter are studied. Their origins and effects are highlighted, and solutions for correction and stabilization are proposed. The different effects induced by them are evidenced by experimental results acquired with a given setup and theoretical simulations carried out for more general cases. We distinguish the errors linked to some imp...

Most patients undergoing breast conservation therapy receive radiotherapy in the supine position. Historically, prone breast irradiation has been advocated for women with large pendulous breasts in order to decrease acute and late toxicities. With the advent of CT planning, the prone technique has become both feasible and reproducible. It was shown to be advantageous not only for women with lar...

The error that a wrong treatment plan be delivered was very serious. We vigorously explore effective method to analyze the factors which lead to this error, thus effectively improves radiotherapy quality. Fault tree analysis has been used for radiotherapy planning errors analysis in this study. After a fault tree was constructed from top to bottom then import the reliability data of basic event...

The reproducibility of patient setup is an important issue for head and neck cancers treated with intensity-modulated radiation therapy (IMRT). In this study, an image-guided radiation therapy (IGRT) system has been used to minimize the uncertainty of patient setup while standard thermoplastic masks were used to provide adequate immobilization for the head and neck. However, they do not provide...

BACKGROUND The cone beam CT (CBCT) guided radiation can reduce the systematic and random setup errors as compared to the skin-mark setup. However, the residual and intrafractional (RAIF) errors are still unknown. The purpose of this paper is to investigate the magnitude of RAIF errors and correction action levels needed in cone beam computed tomography (CBCT) guided accelerated partial breast i...

BACKGROUND The purpose of this study was to determine the feasibility of nondaily image-guided radiotherapy (RT) strategies with intensity-modulated radiotherapy (IMRT) for head and neck cancer. METHODS Alignment data was analyzed from 103 consecutive patients treated by IMRT for head and neck cancer who had undergone daily imaging with onboard mega-voltage CT (MVCT), resulting in 3275 images...

Larynx may alternatively serve as a target or organs at risk (OAR) in head and neck cancer (HNC) image-guided radiotherapy (IGRT). The objective of this study was to estimate IGRT parameters required for larynx positional error independent of isocentric alignment and suggest population-based compensatory margins. Ten HNC patients receiving radiotherapy (RT) with daily CT on-rails imaging were a...

Background: The dose-related effects of patient setup errors on bio-physical indices were evaluated for the conventional wedge (CW) and field-in-field (FIF) whole breast irradiation techniques (WBI). Materials and Methods: The treatment plans of 10 patients receiving left WBI were retrospectively selected for evaluation. The bio-physical effects of dose variations were evaluated by shifting the...

BACKGROUND To analyze setup deviations using daily megavoltage computed tomography (MVCT) and to evaluate three MVCT frequency reducing protocols for gynecologic cancer patients treated with helical tomotherapy. METHODS We recorded the setup errors of 56 patients with gynecological cancer observed throughout their whole course by matching their daily MVCT with the planning CT. Systematic and ...