Background: The spectral coverage of magnetic resonance (MR) sequences can be well assessed in k-space. However, many objects do not provide high signal intensities in the peripheral k-space. Purpose: To experimentall...Background: The spectral coverage of magnetic resonance (MR) sequences can be well assessed in k-space. However, many objects do not provide high signal intensities in the peripheral k-space. Purpose: To experimentally find a phantom that provides a homogeneous spectral pattern also at the high spatial frequencies of the k-space periphery. Material and Methods: Different phantoms were imaged on a 1.5 Tesla magnet, and the resulting MR images were viewed in k-space after fast Fourier transform. Results: Firstly, phantoms with a homogeneous physical structure were studied with a T2-weighted MR sequence, but they provided an inhomogeneous k-space pattern with dominant central low-frequency components. Secondly, phantoms with an inhomogeneous physical structure were studied. In this group, a water-soaked sponge showed a relatively homogeneous k-space pattern also at high spatial frequencies, owing to the fine porous structure. This sponge phantom can also be soaked with Gadolinium chelates for T1-weighted MR imaging. Conclusion: A simple sponge phantom provides a homogeneous k-space pattern, owing to its fine porous structure. This could be utilized in MR sequence development and for viewing the spectral coverage of MR sequences in k-space.展开更多
In this work two different fluorochromes （Alexa 594 and Alexa 680） are conjugated to the same monoclonal antibody （Cetuximab） for obtaining a characteristic M-shaped dual-peak spectrum. Dual-labeling of Cetuximab ...In this work two different fluorochromes （Alexa 594 and Alexa 680） are conjugated to the same monoclonal antibody （Cetuximab） for obtaining a characteristic M-shaped dual-peak spectrum. Dual-labeling of Cetuximab by mixing both fluorochromes before the conjugation step gives spectral results similar to those of mixing of fluorochrome-labeled Cetuximab after the conjugation step （P 〉 0.05）. In conclusion, both methods may be used equivalently for producing a dual-labeled single-antibody probe. Future studies may test whether the M-shaped spectrum may increase the diagnostic confidence in tumor-targeted multispectral optical imaging.展开更多
文摘Background: The spectral coverage of magnetic resonance (MR) sequences can be well assessed in k-space. However, many objects do not provide high signal intensities in the peripheral k-space. Purpose: To experimentally find a phantom that provides a homogeneous spectral pattern also at the high spatial frequencies of the k-space periphery. Material and Methods: Different phantoms were imaged on a 1.5 Tesla magnet, and the resulting MR images were viewed in k-space after fast Fourier transform. Results: Firstly, phantoms with a homogeneous physical structure were studied with a T2-weighted MR sequence, but they provided an inhomogeneous k-space pattern with dominant central low-frequency components. Secondly, phantoms with an inhomogeneous physical structure were studied. In this group, a water-soaked sponge showed a relatively homogeneous k-space pattern also at high spatial frequencies, owing to the fine porous structure. This sponge phantom can also be soaked with Gadolinium chelates for T1-weighted MR imaging. Conclusion: A simple sponge phantom provides a homogeneous k-space pattern, owing to its fine porous structure. This could be utilized in MR sequence development and for viewing the spectral coverage of MR sequences in k-space.
文摘In this work two different fluorochromes （Alexa 594 and Alexa 680） are conjugated to the same monoclonal antibody （Cetuximab） for obtaining a characteristic M-shaped dual-peak spectrum. Dual-labeling of Cetuximab by mixing both fluorochromes before the conjugation step gives spectral results similar to those of mixing of fluorochrome-labeled Cetuximab after the conjugation step （P 〉 0.05）. In conclusion, both methods may be used equivalently for producing a dual-labeled single-antibody probe. Future studies may test whether the M-shaped spectrum may increase the diagnostic confidence in tumor-targeted multispectral optical imaging.
