Related Experiment Video
Updated: Apr 28, 2026
09:11
Y-90 Radioembolization and PD-1 Inhibitor as Neoadjuvant Treatment in Hepatocellular Carcinoma
Published on: May 24, 2024
1.7K
Liver Selective Internal Radiation Therapy with (90)Y resin microspheres: comparison between pre-treatment activity
M Bernardini1, C Smadja1, M Faraggi2
1Nuclear Medicine Department, Hôpital Européen Georges Pompidou (HEGP), Paris, France.
Summary
Comparing Yttrium-90 activity calculation methods for Selective Internal Radiation Therapy (SIRT) reveals significant differences. The partition model (PM) is recommended over Body Surface Area (BSA) methods for personalized patient treatment planning.
Area of Science:
- Nuclear Medicine
- Radiology
- Oncology
Background:
- Selective Internal Radiation Therapy (SIRT) using Yttrium-90 (90Y) resin microspheres is a crucial treatment for liver cancers.
- Accurate calculation of 90Y activity is essential for effective patient-specific treatment planning and optimizing dosimetry.
- Current methods for calculating 90Y activity lack direct comparison, necessitating evaluation for clinical practice.
Purpose of the Study:
- To compare different methods for calculating 90Y resin microsphere activity for SIRT.
- To investigate the relationship between calculated activity, lung breakthrough (LB), tumor-to-normal liver uptake ratio (T/N), and tumor burden.
- To determine the optimal method for patient-specific treatment planning in SIRT.
Main Methods:
- Retrospective analysis of 32 (99m)Tc-macroaggregates (MAA) evaluations and 26 90Y treatments.
- Application of four methods for 90Y activity calculation: three Body Surface Area (BSA)-based and one partition model (PM) based on MIRD formalism.
- Separate analysis of lobar and whole liver treatments, assessing lung doses and T/N ratios.
Main Results:
- Without attenuation correction, lung breakthrough (LB) was overestimated by 65%, but estimated lung doses remained below 30 Gy, not limiting maximal injectable activity (MIA).
- LB showed no significant correlation with T/N, tumor involvement, or radiochemical purity.
- Activity calculations varied significantly between BSA-based and PM methods, especially for lobar treatments (range -85% to 417%).
Conclusions:
- The partition model (PM) method is superior to BSA-based methods for calculating 90Y activity in SIRT due to its consideration of uptake ratios.
- BSA-based methods can lead to excessive healthy liver radiation doses ( > 30 Gy) when T/N < 3.
- The PM method ensures tumor doses exceed 120 Gy when T/N > 4, supporting its use for optimized patient treatment planning.
