Abstract
Spectral photon-counting CT (SPCCT) offers quantitative, high-resolution molecular imaging using intrinsic biomarkers and introduced non-radioactive agents. Thus, SPCCT may open the door to a broader range of medical investigations and increase patient access to advanced diagnostics.
Molecular imaging with SPCCT typically uses non-radioactive pharmaceuticals, which provide several advantages. Firstly, unlike PET, the pharmaceutical can be prepared in advance without the need for extensive infrastructure and an on-site radiochemist. Radioisotopes used in PET imaging have half-lives measured in hours. Therefore, PET often requires a nearby cyclotron, making PET prohibitively expensive. Secondly, clinics will be able to access a range of pharmaceuticals 24 hours a day. In contrast, a PET scan requires planning days in advance and the imaging performed only during specified working hours. Finally, multiple pharmaceuticals can be administered to the same subject simultaneously to investigate more than one molecular process in a single scan. For example, in breast cancer imaging, one pharmaceutical could be used to identify micro-calcifications, while a separate pharmaceutical could be used to identify HER-2 (human epidermal receptor 2) positive cells.
In addition to not needing radioactive agents, SPCCT has higher spatial resolution compared to clinical molecular imaging. SPCCT can resolve objects down to 100 microns, whereas PET typically has a spatial resolution of 1–2 mm. Furthermore, some molecular processes provide enough intrinsic contrast to not need an exogenously administered agent. For example, while calcium and iron are close on the periodic table, the spectral nature of SPCCT enables the two atoms to be differentiated. Moreover, quantification of a molecular process is possible using SPCCT by measuring functionalized high-Z pharmaceuticals (mg/mL) targeted to that molecular process. Although PET has high sensitivity (ng/mL) due to the radioactive isotopes used, the most common PET pharmaceutical (FDG) only measures a single molecular process, thus it is difficult to directly quantify the underlying biological process.
Molecular imaging with SPCCT typically uses non-radioactive pharmaceuticals, which provide several advantages. Firstly, unlike PET, the pharmaceutical can be prepared in advance without the need for extensive infrastructure and an on-site radiochemist. Radioisotopes used in PET imaging have half-lives measured in hours. Therefore, PET often requires a nearby cyclotron, making PET prohibitively expensive. Secondly, clinics will be able to access a range of pharmaceuticals 24 hours a day. In contrast, a PET scan requires planning days in advance and the imaging performed only during specified working hours. Finally, multiple pharmaceuticals can be administered to the same subject simultaneously to investigate more than one molecular process in a single scan. For example, in breast cancer imaging, one pharmaceutical could be used to identify micro-calcifications, while a separate pharmaceutical could be used to identify HER-2 (human epidermal receptor 2) positive cells.
In addition to not needing radioactive agents, SPCCT has higher spatial resolution compared to clinical molecular imaging. SPCCT can resolve objects down to 100 microns, whereas PET typically has a spatial resolution of 1–2 mm. Furthermore, some molecular processes provide enough intrinsic contrast to not need an exogenously administered agent. For example, while calcium and iron are close on the periodic table, the spectral nature of SPCCT enables the two atoms to be differentiated. Moreover, quantification of a molecular process is possible using SPCCT by measuring functionalized high-Z pharmaceuticals (mg/mL) targeted to that molecular process. Although PET has high sensitivity (ng/mL) due to the radioactive isotopes used, the most common PET pharmaceutical (FDG) only measures a single molecular process, thus it is difficult to directly quantify the underlying biological process.
| Original language | English (US) |
|---|---|
| Title of host publication | Photon Counting Computed Tomography |
| Subtitle of host publication | Clinical Applications, Image Reconstruction and Material Discrimination |
| Chapter | 4 |
| Pages | 63-92 |
| Number of pages | 30 |
| ISBN (Electronic) | 9783031260629 |
| DOIs | |
| State | Published - Jan 1 2023 |
Bibliographical note
Publisher Copyright:© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023.
Keywords
- Cancer imaging
- Cardiovascular disease
- Infectious disease
- MARS imaging
- Molecular imaging
- Orthopaedics
- Photon-counting CT
- Preclinical applications
- Spectral
