Table 2 Comparison of diagnostic PET/MRI and PET/MRI simulator for radiotherapy positioning
| Â | Diagnostic PET/MRI | PET/MRI simulator |
|---|---|---|
Purpose | Exploration, qualitative evaluation, staging, assisted target delineation, efficacy evaluation and prognosis prediction | To provide imaging data for target volume delineation in the 3D direction |
Positioning device | Does not involved | Positioning devices such as thermoplastic masks and laser system are used to fix the patient’s position |
Anterior receiver coil | RF coil could touch and deform the surface of the patients | RF coil was fixed by the coil holder away from the patient’s surface, ensuring a gap for the placement of the positioning device and repeatability of each positioning for the patient |
Treatment bed | Diagnostic PET/MRI is the curved one | The PET/MRI simulator is the flat one |
Image quality | MRI image: • No positioning device • Almost no effect with coil • A negligible effect with treatment bed PET image: • No positioning device • A slight effect with coil • A slight effect with treatment bed | MRI image: • A slight effect with positioning device • No image distortion with coil and coil holder • A negligible effect with treatment bed PET image: • Almost no effect with positioning device • A slight effect with coil and coil holder • A slight effect with treatment bed |