Our study was designed to examine the validity of dual energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) measurements as predictors of whole bone breaking strength in beagle femora. DXA was used to determine the bone mineral content, bone area, and 'areal' bone mineral density. PQCT was used to determine the cross-sectional moments of inertia, volumetric d...

Two patients with multiple lung metastases (≥ 5) were treated using frameless stereotactic body radiation therapy (SBRT) on an Elekta Axesse linear accelerator equipped with an interdigitation-capable multileaf collimator and four-dimensional cone-beam CT (4D CBCT). The technique and the early clinical outcomes were evaluated. Patient A with five lung metastases and Patient B with seven lung me...

OBJECTIVES Cone beam computed tomography (CBCT) is an innovative dental of imaging system characterized by rapid volumetric imaging with patient exposure to a single dose of radiation. The present study was carried out to compare the linear measurements obtained with CBCT and digital caliper in 20 mandibles from human cadavers. STUDY DESIGN A total of 4800 linear measurements were measured be...

With the widespread use of low-dose computed tomography for screening lung cancer in high-risk groups, detection

background: to evaluate the dosimetric difference between conventional and three-dimensional conformal radiotherapy (3d-crt) using 6 and 18 mv x-ray photons. materials and methods: computed tomography scans of 26 pelvic patients were acquired and transferred to the 3d treatment planning system. for each patient, 8 conventional plans (3, 4, 5 and 6 fields) and one 3d-crt plan were prepared using...

PURPOSE To develop and validate a fully automatic region-of-interest (ROI) delineation method for on-line adaptive radiotherapy. METHODS AND MATERIALS On-line adaptive radiotherapy requires a robust and automatic image segmentation method to delineate ROIs in on-line volumetric images. We have implemented an atlas-based image segmentation method to automatically delineate ROIs of head-and-nec...

Since the introduction of volumetric chemical dosimetry with Fricke gel dosimeters in the 1980s, three-dimensional (3D) dosimetry has been a promising technique for the clinic, since it provides a unique methodology for 3D dose measurement of the complex conformal dose distributions achieved by modern techniques such as Intensity Modulated and Volumetric Arc Radiation Therapy. In the last decad...

abstract   background: while the benefits of computed tomography (ct) are well known in accurate diagnosis, those benefits are not risk free. ct is a device with higher patient dose in comparison with other conventional radiological procedures. is the reduction of exposures by requiring optimization of ct procedures [a principle concern in radiological protection]? in this study, the radiation ...

OBJECTIVE The aim of this prospective study was to evaluate the performance of ultra-low dose CT for the diagnosis of pediatric-like fractures and ascertain the lowest dose level sufficient for diagnostics. MATERIALS AND METHODS Fifty-one bones of young pig cadavers were artificially fractured and subsequently examined by using a 64 multi-detector CT with 36 various dose levels down to a dose...

OBJECTIVES To compare the effectiveness of two different patient size metrics based on water equivalent diameter (Dw ), the mid-scan water equivalent diameter Dw_c , and the mean (average) water equivalent diameter in the imaged region, Dw_ave , for automatic detection of accidental changes in computed tomography (CT) acquisition protocols. METHODS Patient biometric data (height and weight) w...