BACKGROUND Respiration-correlated CT (4D CT) is the basis of radiotherapy treatment planning of thoracic and abdominal tumors. Current clinical 4D CT images suffer, however, from artifacts due to unfulfilled assumptions concerning breathing pattern regularity. We propose and evaluate modifications to existing low-pitch spiral 4D CT reconstruction protocols to counteract respective artifacts. ...

BACKGROUND AND PURPOSE Routine CT of the brain is traditionally performed with sequential CT. We assessed whether sequential CT can be replaced with thinly collimated multisection spiral CT without loss of image quality. MATERIALS AND METHODS An observer study was conducted using data from 23 patients who were scanned with both a sequential (collimation, 4 x 5 mm) and a spiral technique (coll...

We present a harmonic expansion of the observed line-of-sight velocity field as a method to recover and investigate spiral structures in the nuclear regions of galaxies. Application to the emission-line velocity field within the circumnuclear starforming ring of NGC1097, obtained with the GMOS-IFU spectrograph, reveals a three-arm spiral in the non-circular motions, which agrees with a two-arm ...

Context. Various morphologies such as multi-concentric shells and spiral-like patterns have been observed around Proto-Planetary Nebulae and AGB stars. It is widely argued that the regular density patterns are produced by binary systems. Aims. The goal is to build up a simple dynamical model for the out-flowing circumstellar envelope around AGB stars in a wide binary system to explore the param...

Cubic spiral is a curve whose direction is a cubic polynomial of arc length. It has been used as a path primitive for nonholonomic car-like mobile robot with restricted turning capability in free environment [1], [2]. In this paper, we investigate the use of cubic spiral segments for car-like mobile robots moving from a given start configuration to a given goal configuration in an environment c...

BACKGROUND In order to acquire a high quality image with a low radiation dose, prospective electrocardiogram (ECG)-triggered computed tomography coronary angiography (CTCA) requires a stable heart rate (HR) < 65 beats/min. Esmolol has the advantage of reducing HR. The objective of this article is to assess the value of intravenous esmolol treatment before prospective ECG-triggered high-pitch sp...

BACKGROUND The aim of this study was to evaluate the amount of radiation doses absorbed by soft tissues (entrance skin dose) with a low-dose spiral computed tomography (CT) protocol compared to conventional X-ray techniques commonly used in orthodontics. METHODS The amount of skin dose has been evaluated using a tissue-equivalent head-neck radiotherapy humanoid phantom with thermoluminescent ...