No significant differences were found between the area under the receiver operating characteristic curve of the digital and that of the conventional radiography method for almost all investigated criteria .The only exception （例外；异议）was mediastinal abnormalities, for which the digital method provided better results than the conventionvl method (P
Invasive breast cancer detection by mammography may be improved through attention to correct positioning.
For CT of the brain, there are there standard reference lines; the orbitomeatal line, the Reid baseline, and the supraorbitomeatal line.The orbitomeatal line runs through the external canthus and the center of the external auditory meatus.This is the most widely used line, because acquisition of fewer sections is neceary to cover the entire brain.The Reid baseline runs though the inferior orbital wall and the superior border of the external auditory meatus.This line is paraller to the optic nerve and provides the best demonstration of the orditai contents.The supraorbitomeatal line runs through the superior orbital wall and the center of the external auditory meatus.This line approximately parallels the skull base.We developed reference lines for use at MR imaging that are analogous to the three standard reference lines used at CT, on the basis of anatomic landmarks that are visible on midsagittal MR images.These lines can be used to prescribe subsequent oblique axial sequences.
During the past decade , many investigators have addreed the feasibility of picture archiving and communication system (PACS) as an alternative to film-based radiology.To succefully implement the PACS, a number of factors such as film resolution, interpretation conditions, and a cost-effective viewer system must be taken into consideration.The most important clinical criterion for using the PACS technology is the ability to achieve acceptable accuracy when interpreting radiologic images at a soft-copy viewing workstation.Most previous reports have focused on a comparison of observer performance with soft-copy and hard-copy imajes, and such studies have been performed using chest radiography.However, observer performance in projection radiography of another anatomic section must also be compared to achieve that the PACS can completely replace film-based radiology.
CT in an invaluable tool in the diagnosis of the chest diseases with high-resolution CT (HRCT) providion exquisite visualization of the pulmonary interstitium.However, CT examinations do not come without a cose..A report from the 2002 National Conference on Dose Reduction in CT indicates that CT now represents the largest single source of medical radiation exposure.Although CT constitutes only 15% of the total number of examinations in some university departments, it can account for 70% of the dose delivered.
