Med Phys
-
Accurate segmentation of lungs with severe interstitial lung disease (ILD) in thoracic computed tomography (CT) is an important and difficult task in the development of computer-aided diagnosis (CAD) systems. Therefore, we developed in this study a texture analysis-based method for accurate segmentation of lungs with severe ILD in multidetector CT scans. ⋯ Our lung segmentation method provided accurate segmentation results for abnormal CT scans with severe ILD and would be useful for developing CAD systems for quantification, detection, and diagnosis of ILD.
-
The aim of this study was to develop a 4D-modeling algorithm, designated "3D+," to simulate organ movement and deformation for 4D dose calculation without the need for 4D-CT or deformable image registration and to assess the validity of this algorithm. ⋯ 4D modeling of the thorax utilizing the 3D+ algorithm shows acceptable accuracy and is more suited for routine clinical use in terms of processing time than conventional 4D-CT and deformable image registration. The 3D+ algorithm may be useful for simulating dose distribution for advanced beam delivery techniques, such as real-time tumor tracking irradiation and adaptive radiation therapy.
-
Conventional radiography has been for decades the standard method of evaluation for cervical spine trauma patients. However, currently available helical multidetector CT scanners allow multiplanar reconstruction of images, leading to increased diagnostic accuracy. The purpose of this study was to determine the relative benefit/risk ratio between cervical spine CT and cervical spine radiography and between cervical spine CT and cervical spine radiography, followed by CT as an adjunct for positive findings. ⋯ According to the decision model calculations, the use of CT is more favorable over the use of radiography alone or radiography with CT by a factor of 13, for low risk 20 yr old patients, to a factor of 23, for high risk patients younger than 80 yr old. The radiography/CT imaging strategy slightly outperforms plain radiography for high and moderate risk patients. Regardless of the patient age, sex, and fracture risk, the higher diagnostic accuracy obtained by the CT examination counterbalances the increase in dose compared to plain radiography or radiography followed by CT only for positive radiographs and renders CT utilization justified and the radiographic screening redundant.
-
Daily setup for head and neck (HN) radiotherapy (RT) can vary randomly due to neck rotation and anatomy change. These differences cannot be totally corrected by the current practice of image guided RT with translational repositioning. The authors present a novel rapid correction scheme that can be used on-line to correct both interfractional setup variation and anatomy change for HN RT. ⋯ The target coverage and OAR sparing for the SAM/SWO plans were found to be equivalent to the original plan. The SAM/SWO process took 5-8 min for the head and neck cases studied. The proposed aperture morphing with weight optimization is an effective on-line approach for correcting interfractional patient setup and anatomic changes for head and neck cancer radiotherapy.
-
Magnetic resonance spectroscopy (MRS) has been shown to have great clinical potential as a supplement to magnetic resonance imaging in the detection of prostate cancer (CaP). MRS provides functional information in the form of changes in the relative concentration of specific metabolites including choline, creatine, and citrate which can be used to identify potential areas of CaP. With a view to assisting radiologists in interpretation and analysis of MRS data, some researchers have begun to develop computer-aided detection (CAD) schemes for CaP identification from spectroscopy. ⋯ In addition, the scheme was found to be robust to changes in system parameters. For 6 of the 18 studies an expert radiologist laboriously labeled each of the individual spectra according to a five point scale, with 1/2 representing spectra that the expert considered normal and 3/4/5 being spectra the expert deemed suspicious. When evaluated on these expert annotated datasets, the CAD system yielded an average sensitivity (cluster corresponding to suspicious spectra being identified as the CaP class) and specificity of 81.39% and 64.71%, respectively.