PET/CT is widely used to detect and monitor diseases such as cancer. PET provides information about biological activity in the body, while CT helps locate these findings and is also used to correct the PET images. However, CT adds additional radiation exposure.
This thesis by Samaneh Mostafapour investigated how far the radiation dose from CT can be reduced while still obtaining reliable PET results. Using modern long-axial-field-of-view PET/CT technology, different ultra-low-dose CT approaches were evaluated in phantoms and patients. In one clinical study, the CT radiation dose was reduced by approximately 97%, while differences in important PET measurements generally remained below 3%.
The research also investigated how very-low-dose CT affects automatic organ segmentation and whether artificial intelligence can improve these images. AI improved image appearance but did not completely replace the need for conventional CT when detailed anatomical information was required. Photon-counting CT was also explored as a promising technology for future low-dose PET/CT.
Overall, ultra-low-dose CT can substantially reduce radiation exposure while maintaining reliable PET measurements, but the appropriate dose depends on the patient and the purpose of the CT scan.
Find the full thesis here: Ultra-low-dose CT for positron emission tomography: feasibility, limitations, and quantitative impact
