Phantom imaging

Figure 7.17 Phantom images of lanthanoid-metallofullerols [172]. (Reprinted with permission from H. Kato, et al., Lanthanoid endohedral metallofnllerenols for MRI contrast agents, Journal of the American Chemical Society, 125, 4391 397, 2003. 2003 American Chemical Society).

In contrast, ACR emphasizes the quality control, calibration of the equipment, and technology used in the procedures, and accordingly has developed three modules - module 1 for oncology, module 2 for brain, and module 3 for heart. A PET center must apply for all modules that are performed at the facility. For accreditation, the facility is required to submit information on the quality control and quality assurance program, data collection, reporting, radiopharmaceuticals procedures, and laboratory safety, along with chnical and approved phantom images. So, all equipment in a PET center is required to be calibrated and tested for accurate functionahty for accreditation by ACR. 

Fig. 41 shows the fusion of two 3-D phantom images, i.e. a solid cube and a 3-D texture, which consists of a grid of lines parallel to the three axes. Cross-sections of the input images and the fused image are also displayed in Fig. 41. 

Fig. 3.23. Lag ghosting in a DR detector phantom image (1) thumbnail image of the mean values in different ROls (2) obtained from a DR system in which a typical lag ghost can be...

Fig. 3.24. Scan line artifacts in a CR system phantom image (1) thumbnail image of the SNR in different ROls (2) obtained from a CR system in which a row of pixels is not shown with the proper data due to a scan line artifact in the CR reader (a). Additional artifacts that can be seen are (b) scratches on the Imaging Plate (IP), (c) a bad phosphor uniformity and (d) local point artifacts due to phosphor damage...

The particles were shown to be multimodal in their capacity to provide both CT and MR contrast. Synchrotron radiation computed tomography (SRCT) phantom imaging was obtained at a gold concentration of 1.4mg mLr which is lower than the detection threshold of a conventional CT scanner. In vivo SRCT images of mice and rats were obtained at a concentration of 10 mg mL7 which corresponds to a 5mM Gd. MR images were enhanced by the presence of the particles. Postmortem ICP mass spectrometry showed the particles to distribute mostly to the kidneys of the animals, where they were readily cleared in the urine. Interestingly,... 

One very important property to remember about collimators is that the spatial resolution gets worse as the source-to-collimator distance increases. This is illustrated in the set of phantom images that were acquired from 5 to 30 cm from the collimator surface. To obtain the best-quality images, spatial resolution comes at the price of count sensitivity therefore it is crucial to keep the collimator as close to the patient as possible. 

Figure 24.15 Comparison of phantom images acquired during static activations of the silicone-made folded actuator (a) control Image recorded with the actuator outside the scanner (b-e) images obtained while driving the actuator Inside the scanner at 0, 4, 6 and 8 V/ym, respectively (b -d ) subtraction of the control Image (a) from the Images (b-e).

Enhanced Distance Active Contour (EDAC) is introduced in order to solve the issue. In this paper, the efficiency of DAC and EDAC in segmenting characteristic details on breast phantom images is compared. In this study, the breast phantom is needed in order to test the applicability of EDAC, in the detection of the characteristic details hidden behind the phantom. The breast phantom refers to a test object used to simulate radiographic characteristics of compressed tissue. A phantom is designed to simulate x-ray attenuation of 4.2 cm compressed human breast which is composed of 50% adipose and 50% glandular tissue. Then, both methods are implemented on mammograms to segment microcalcifications [3]. Einally, the performance of both methods are measured and compared. This is to verify that the EDAC performs better than DAC. 

Lalwani G, Sundararaj JL, Schaefer K, Button T, Sitharaman B. Synthesis, characterization, in vitro phantom imaging, and cytotoxicity of a novel graphene-based multimodal magnetic resonance imaging-X-ray computed tomography contrast agent. J Mater Chem B 2014 2 3519-30. 

Phantom images of Yb(STHP) at pH 4,5, and 7 exhibit contrast only at the most acidic pH. However, addition of two equivalents of DEP (D, E, F) shows that contrast is now brightest for the tube at neutral pH [64]. 

Figure 8.21 CEST phantom images. Lower row W is water for control. A-F contain 5mM Yb(STHP), 20mMbuffer, WOmMNaCI. Middlerow AatpH4.6,BatpH5.5, CatpHJ.O. Top row after addition of WmM DEP, D at pH 4.6, E at pH 5.5, F at pH 7.0. Reproduced with...

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