厂家：mex, inc. 品名：mammographicaccreditation phantom model 156 型号：mex 156, mex model 156 ------------------------ 尺寸： dimensions phantom body material . . . . . . . acrylic phantom dimensions . . . . . . . 4.5x10.2x10.8 cm (hwd) (1.75x4x4.25 in) acrylic base . . . . . . . . . . . . . . 3.3 cm (1.3 in) thick cover . . . . . . . . . . . . . . . . . . . .0.3 cm (0.12 in) thick acrylic disk . . . . . . . . . . . . . . . 4 mm thick x 1 cm diameter test objects . . . . . . . . . . . . . . .nylon fibrils (1.56, 1.12, 0.89, 0.75, 0.54 and 0.40 mm nylon fibers) simulated microcalcifications.(0.54, 0.40, 0.32, 0.24 and 0.16 mm specks) tumor-like masses . . . . . . . . .(2.00, l.00, 0.75, 0.50, 0.25 and 0.16 mm specks) included is a film, which is a contact image of the wax insert of your mex 156 ---------------------- 产品介绍： the mammographic accreditation phantom model 156 is designed to test the performance of a mammographic system by evaluation of the system’s ability to image small structures similar to those found clinically. objects within the phantom were designed to simulate micro-calcifications, fibrous structures in ducts, and tumor-like masses, small structures that are important in the early detection of breast cancer. test objects within the phantom range in size from those that should be visible on any system to objects that will be difficult to see even on the best mammographic systems. storage and handling store the mammographic accreditation phantom model 156 in a cool dry area avoiding temperature extreme such as intense heat and direct sunlight, or freezing temperatures. impact stress may cause breakage. 3 product description the mammographic phantom is made up of a wax block containing 16 various sets of test objects, a 3.3 cm (1.3 in.) thick acrylic base, a tray for placement of the wax block, and a 0.3 cm (0.12 in.) thick cover. all of this together approximates a 4.2 cm compressed breast. five groups of simulated micro-calcifications, six different size nylon fibers simulate fibrous structures, and five different size tumor-like masses are included in the wax insert. figure 1 lists the sizes of the test objects and their position in relation to the notched corner of the wax block. 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 figure 1: location of the test objects in the wax insert. note: numbers are for reference only. 4 region materials 1. 1.56 mm nylon fiber 2. 1.12 mm nylon fiber 3. 0.89 mm nylon fiber 4. 0.75 mm nylon fiber 5. 0.54 mm nylon fiber 6. 0.40 mm nylon fiber 7. 0.54 mm simulated micro-calcification 8. 0.40 mm simulated micro-calcification 9. 0.32 mm simulated micro-calcification 10. 0.24 mm simulated micro-calcification 11. 0.16 mm simulated micro-calcification 12. 2.00 mm thick tumor-like mass 13. 1.00 mm thick tumor-like mass 14. 0.75 mm thick tumor-like mass 15. 0.50 mm thick tumor-like mass 16. 0.25 mm thick tumor-like mass 5 a 4 mm thick, 10 mm diameter acrylic disk is also provided with each phantom. the disk is used to establish and monitor a density difference with respect to your facility’s operating level. it should be placed on top of the phantom in a consistent location in the image area so it does not obscure details in the phantom and where it can not cast a shadow on any portion of the aec detector. according to the acr mammography qc manual, a suitable location is between and slightly below the first and second largest fibers. using the phantom* set up 1. center the phantom on the image receptor surface with the nipple indent marker positioned away from the chest wall, just as the nipple of the patient’s breast, and the chest wall edge of the phantom aligned with the wall side of the image receptor. 2. position the x-ray tube and compression device as you would for a craniocaudal examination. 3. select the mammographic machine settings appropriate for a 4.2 cm compressed breast. if the phototimer is used, set the phototimer to the center position under the wax portion of the phantom. 4. make an exposure. process the film. if using a digital mammographic system, follow the manufacturer’s image processing and display requirements. image evaluation the 156 map conforms to the requirements of the american college of radiology for use in the acr accreditation program. the phantom may be used to evaluate both screen/film and digital images. ** facilities participating in the acr accreditation program will use and evaluate the phantom images in accordance with that program. facilities following other national or regional guidelines should refer to those standards. 1. background optical should be greater than 1.40 o.d. for screen/film images. the density difference between the acrylic disk and the background should be at least 0.4. once the density difference is established as an operat ing level, subsequent density difference measurements should be within +/- 0.05 o.d. 2. the target mean glandular dose required to achieve the optical density is as tabulated in the acr mammography quality assurance manual for different anode/filter com binations. your alternative national or regional stan dards. 3. phantom images should be read under optimal condi tions. use of a x2 or greater magnifying glass or digital image manipulation tools is recommended. viewbox luminance an ambient light levels should be optimized. 4. the acr requires that the reader must be able to see all of the 0.75 mm fiber, all of the 0.75 mm mass and all six of the 0.32 mm specks. as many systems can surpass this minimum, attention to degradation over time is as important as meeting the minimum requirement. failure to meet the minimum image quality requirements set either internally or by your accreditation or regulatory agency should prompt investigation and corrective action. you should consult with a medical physicist or engineer who specializes in mammography and/or diagnostic radiology. following the correction, the system should be retested and the new results documented. *this manual provides a recommended use of the 156 phantom for routine quality assurance in addition to, or in lieu of any other program. **at the time of this writing, testing of the full field digital mammography systems in the united states must follow the manufacturer’s quality control manual.