PURPOSE It is aim to test the hypothesis that a dynamic keyhole MRI reconstruction technique using external/internal respiratory surrogate position reduces acquisition time while retaining image quality for real-time tumor monitoring, compared to the conventional keyhole technique. METHODS 46 thoracic MRI studies with 13 healthy human subjects have been acquired using a 3T GE MRI. Acquired MR...

We aimed to optimize internal margin (IM) determination for respiratory-gated radiotherapy using end-expiratory phase assessments using a motion phantom. Four-dimensional computed tomography (4D CT) data were acquired using a GE LightSpeed RT CT scanner, a respiratory-gating system, and a motion phantom designed to move sinusoidally. To analyze the accuracy of 4D CT temporal resolution, a 25.4 ...

Surface chest motion can be easily monitored with a wide variety of sensors such as pressure belts, fiber Bragg gratings and inertial sensors, etc. The current applications of these sensors are mainly restricted to respiratory motion monitoring/analysis due to the technical challenges involved in separation of the cardiac motion from the dominant respiratory motion. The contribution of heart to...

Respiratory-gated treatment techniques have been introduced into the radiation oncology practice to manage target or organ motions. This paper will review the implementation of this type of gated treatment technique where the respiratory cycle is determined using an external marker. The external marker device is placed on the abdominal region between the xyphoid process and the umbilicus of the...

4D image-guided radiation therapy (IGRT) for free-breathing lungs is challenging due to the complicated respiratory dynamics. Effective modeling of respiratory motion is crucial to account for the motion affects on the dose to tumors. We propose a shape-correlated statistical model on dense image deformations for patient-specic respiratory motion estimation in 4D lung IGRT. Using the shape defo...

Purpose: MRI is a relatively slow imaging modality. Patient respiratory motion significantly reduces diagnostic image quality, especially in the abdomen. Usually, motion is detected with a respiratory belt and/or navigators[1]. The belt is an extra device which demands careful positioning on the patient to be a reliable indicator of the respiratory motion. The navigator[2] is an MR based sensor...

Magnetic resonance (MR) coronary imaging is susceptible to artifacts caused by motion of the heart. The purpose of this thesis was to study the respiratory motion of the coronary arteries and to use the results to develop strategies for improved MR imaging. The first section of the thesis describes an MR motion correction technique for objects undergoing a 3D affine transformation. The remainde...

The purpose of this study was to test the feasibility of using respiratory correlated mega voltage cone-beam computed tomography (MVCBCT), taken during patient localization, to quantify the size and motion of lung tumors. An imaging phantom was constructed of a basswood frame embedded with six different-sized spherical pieces of paraffin wax. The Quasar respiratory motion phantom was programmed...