Timothy Pok Chi Yeung

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INTRODUCTION Set-up accuracy of different image-guidance (IG) protocols using reduced imaging frequency was compared with daily IG. Anatomical characteristics were investigated for their potential to help select the suitable IG protocols for individual patients. METHODS Set-up corrections from 26 prostate cancer patients treated with daily IG on helical(More)
Patients with high-grade gliomas usually have heterogeneous response to surgery and chemoirradiation. The objectives of this study were (1) to evaluate serial changes in tumor volume and perfusion imaging parameters and (2) to determine the value of these data in predicting overall survival (OS). Twenty-nine patients with World Health Organization grades(More)
Dynamic perfusion CT (PCT) is an imaging technique for assessing the vascular supply and hemodynamics of brain tumors by measuring blood flow, blood volume, and permeability-surface area product. These PCT parameters provide information complementary to histopathologic assessments and have been used for grading brain tumors, distinguishing high-grade(More)
RATIONALE AND OBJECTIVES The aim of this study was to investigate the effect of scan duration on the measurement of blood flow (BF), blood volume (BV), and permeability-surface area product (PS) in patients undergoing computed tomography (CT) perfusion for brain tumors. MATERIALS AND METHODS CT perfusion scans were performed in 14 patients with malignant(More)
PURPOSE Stereotactic ablative radiation therapy (SABR) is a guideline-specified treatment option for early-stage lung cancer. However, significant posttreatment fibrosis can occur and obfuscate the detection of local recurrence. The goal of this study was to assess physician ability to detect timely local recurrence and to compare physician performance with(More)
IntroductionThis study aimed to explore the potential for computed tomography (CT) perfusion and 18-Fluorodeoxyglucose positron emission tomography (FDG-PET) in predicting sites of future progressive tumour on a voxel-by-voxel basis after radiotherapy and chemotherapy. MethodsTen patients underwent pre-radiotherapy magnetic resonance (MR), FDG-PET and CT(More)
BACKGROUND The therapeutic efficacy of stereotactic radiosurgery for glioblastoma is not well understood, and there needs to be an effective biomarker to identify patients who might benefit from this treatment. This study investigated the efficacy of computed tomography (CT) perfusion imaging as an early imaging biomarker of response to stereotactic(More)
Dynamic contrast-enhanced perfusion and permeability imaging, using computed tomography and magnetic resonance systems, are important techniques for assessing the vascular supply and hemodynamics of healthy brain parenchyma and tumors. These techniques can measure blood flow, blood volume, and blood-brain barrier permeability surface area product and, thus,(More)