Alanezi, A 2022, Evaluation of the effect of breast implants on the accuracy of the CT attenuation Correction (CTAC) map for SPECT/CT myocardial perfusion imaging: a phantom study , PhD thesis, University of Salford.
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Abstract
Background: Myocardial perfusion imaging (MPI) using single photon emission computed tomography (SPECT) imaging can assess myocardial viability and perfusion. However, overlying thoracic structures, such as ribs or breast tissue lead to gamma ray attenuation. This attenuation does not occur equally for all body regions. Photons emitted from deeper structures will undergo more attenuation than superficial structures, causing artefacts within the image that can mimic pathology - such as ischaemia. Such artefacts can be removed or minimised by using attenuation correction (AC) maps generated using computed tomography (CT). Breast implants that have density higher than normal breast tissue, could affect the accuracy of the CT numbers used for AC. Methods: Imaging protocols were compared with and without three sizes of breast implant, in a phantom study. The first experiment used a diagnostic CT scanner to design the method. The second experiment was carried out in a clinical centre using the CT components of a SPECT/CT scanner to assess the impact of three different breast implants on CT number accuracy when the CTAC is applied in SPECT/CT MPI. The last experiment used a clinical SPECT/CT scanner and 99mTC as a radiotracer to mimic the clinical MPI scan. Results: The first and second experiments found that large breast implants led to a greater difference in CT HU and CT numbers compared to baseline, than the small or medium implants, but the differences were within the tolerance range (±5HUs). This suggested that even large breast implants did not impact in a clinically significant way on the accuracy of CT HUs and CT numbers. However, the third experiment found that large breast implants resulted in a more significant difference in corrected counts and thus more overcorrection than small or medium breast implants. Conclusion: The study illustrates that large breast implants resulted in a greater differences in CT HUs, CT number and corrected counts than small or medium implants. Increasing the tube current (mA) improves the CT HU accuracy without significant impact, apart from an increase in the radiation dose to the patient.
| Item Type: | Thesis (PhD) |
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| Contributors: | Kenney, LPJ (Supervisor) and Szczepura, K (Supervisor) |
| Schools: | Schools > School of Health Sciences Schools > School of Health and Society |
| Depositing User: | Abdullah Jadia O Alanezi |
| Date Deposited: | 02 Feb 2023 09:21 |
| Last Modified: | 02 Mar 2023 02:30 |
| URI: | https://usir.salford.ac.uk/id/eprint/65944 |
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