Add like
Add dislike
Add to saved papers

Improving the CT (140 kVp) to PET (511 keV) conversion in PET/MR Hardware Component Attenuation Correction.

Medical Physics 2020 Februrary 13
PURPOSE: Today, attenuation correction (AC) of PET/MR hardware components is performed by using an established method from PET/CT hybrid imaging. As shown in previous studies, the established mathematical conversion from CT to PET attenuation coefficients may, however, lead to incorrect results in PET quantification when applied to AC of hardware components in PET/MR. The purpose of this study is to systematically investigate the attenuating properties of various materials and electronic components frequently used in the context of PET/MR hybrid imaging. The study, thus, aims at improving hardware component attenuation correction in PET/MR.

MATERIAL AND METHODS: Overall, 38 different material samples were collected; a modular phantom was used to for CT, PET, and PET/MR scanning of all samples. CT-scans were acquired with a tube voltage of 140 kVp to determine Hounsfield Units (HU). PET transmission scans were performed with 511 keV to determine linear attenuation coefficients (LAC) of all materials. The attenuation coefficients were plotted to obtain an HU to LAC correlation graph, which was then compared to two established conversions from literature. Hardware attenuation maps of the different materials were created and applied to PET data reconstruction following a phantom validation experiment. From these measurements, PET difference maps were calculated to validate and compare all three conversion methods.

RESULTS: For each material, the HU and corresponding LAC could be determined and a bi-linear HU to LAC conversion graph was derived. The corresponding equation was y = 1.64 * 10-5 × (HU + 1000) + 8.3 * 10-2 . While the two established conversions lead to a mean quantification PET bias of 4.69 % ± 0.27 % and -2.84 % ± 0.72 % in a phantom experiment, PET difference measurements revealed only 0.5 % bias in PET quantification when applying the new conversion resulting from this study.

CONCLUSION: An optimized method for the conversion of CT to PET attenuation coefficients has been derived by systematic measurement of 38 different materials. In contrast to established methods, the new conversion also considers highly attenuating materials, thus improving attenuation correction of hardware components in PET/MR hybrid imaging.

Full text links

We have located links that may give you full text access.
Can't access the paper?
Try logging in through your university/institutional subscription. For a smoother one-click institutional access experience, please use our mobile app.

For the best experience, use the Read mobile app

Mobile app image

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app

All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.

By using this service, you agree to our terms of use and privacy policy.

Your Privacy Choices Toggle icon

You can now claim free CME credits for this literature searchClaim now

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app