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Updated: Aug 25, 2026
Non-Invasive PET/MR Imaging in an Orthotopic Mouse Model of Hepatocellular Carcinoma
Published on: August 31, 2022
Liver tumors: MR imaging of radioactive holmium microspheres--phantom and rabbit study
Johannes F W Nijsen1, Jan-Henry Seppenwoolde, Thomas Havenith
1Department of Nuclear Medicine, University Medical Centre, Heidelberglaan 100, Room E02.222, 3584 CX, Utrecht, The Netherlands. f.nijsen@azu.nl
Purpose:
To investigate the use of magnetic resonance (MR) imaging in the administration and biodistribution of holmium-loaded poly(L-lactic acid) microspheres (Ho-PLLA-MS) in liver tumors.
Materials And Methods:
MR imaging measurements were obtained in phantoms, three ex vivo rabbit livers, and four livers in living rabbits. When applicable, measurements were compared with those on scintigraphic images. The transverse relaxivity R2* of the Ho-PLLA-MS was determined in a phantom study. The in vivo animal experiments were performed by using rabbits with an implanted VX2 tumor. Detection of passing Ho-PLLA-MS to estimate lung shunting was performed in a scaled model of the vena cava.
Results:
In the ex vivo liver experiments, the feasibility of real-time MR imaging during administration of microspheres was demonstrated. The in vivo rabbit experiments demonstrated that MR imaging can depict radioactive, nonradioactive, and decayed Ho-PLLA-MS after treatment for as long as they remain in the body. Furthermore, this study showed the ability of dynamic MR imaging to detect single doses of passing Ho-PLLA-MS.
Conclusion:
Ho-PLLA-MS used for internal radionuclide therapy can be imaged clearly in vivo with MR imaging.
Insights
Magnetic resonance (MR) imaging can clearly visualize holmium-loaded poly(L-lactic acid) microspheres (Ho-PLLA-MS) in liver tumors. This technique allows for tracking of Ho-PLLA-MS during administration and biodistribution for internal radionuclide therapy.
Area of Science:
- Medical imaging
- Radiotherapy
- Biomaterials
Background:
- Holmium-loaded poly(L-lactic acid) microspheres (Ho-PLLA-MS) are utilized in internal radionuclide therapy for liver tumors.
- Effective monitoring of microsphere administration and biodistribution is crucial for treatment efficacy.
- Magnetic resonance (MR) imaging offers non-invasive visualization capabilities.
Purpose of the Study:
- To evaluate the utility of MR imaging for tracking Ho-PLLA-MS during administration and biodistribution in liver tumors.
- To assess the feasibility of real-time MR imaging during microsphere delivery.
- To determine if MR imaging can depict Ho-PLLA-MS in vivo after treatment.
Main Methods:
- MR imaging measurements were performed in phantoms, ex vivo rabbit livers, and in vivo rabbit liver tumor models.
- Transverse relaxivity (R2*) of Ho-PLLA-MS was determined.
- Dynamic MR imaging was used to detect Ho-PLLA-MS in a vena cava model to estimate lung shunting.
Main Results:
- Real-time MR imaging during microsphere administration was feasible in ex vivo liver experiments.
- In vivo MR imaging successfully depicted radioactive, nonradioactive, and decayed Ho-PLLA-MS in rabbit livers.
- Dynamic MR imaging demonstrated the ability to detect single doses of passing Ho-PLLA-MS.
Conclusions:
- MR imaging is a viable tool for clear in vivo visualization of Ho-PLLA-MS.
- This imaging modality can support the administration and biodistribution monitoring of Ho-PLLA-MS in liver tumor radionuclide therapy.
