Optimizing 90Y Particle Density Improves Outcomes After Radioembolization

Yttrium-90 Radioembolization Dosimetry: Dose Considerations, Optimization, and Tips

“…• There is emerging evidence suggesting that the number of microspheres per volume, known as particle loading, can impact tumor response outcomes. 34,40 With that in mind, the general idea of choosing the correct number of particles to deliver remains based on the hypothesis that large masses benefit from a higher number of lower specific activity microspheres able to provide an adequate particle distribution, while smaller masses benefit from a lower number of higher specific activity microspheres. To date, no optimal threshold for tumor particle loading has been confirmed via clinical trial.…”

Techniques to Optimize Radioembolization Tumor Coverage

“…After filling the larger vessels, additional microspheres administered later flow into the smaller, higher resistance vessels surrounding the lesion, thereby providing a more uniform distribution of radiation to the tumor and its microenvironment. 7 Hepatocellular carcinoma and liver metastases, like many other neoplasms, are known for having complex and heterogeneous internal and external microenvironments. 8 With varying degrees of vascularity, extracellular fibrosis, and susceptibility to radiation, some of these liver lesions may be resistant to treatment given their underlying microenvironment heterogeneity.…”

“…Conversely, hypovascular lesions (T/N < 2.6) treated with a higher number of particles (>6,000 spheres/mL) also had a better local progression-free survival. 7 The authors postulated that radioembolization of a hypovascular liver lesion leads to a greater number of particles flowing to normal parenchyma and less to the tumor, therefore requiring a higher number of particles to improve treatment response. In contrast, microspheres preferentially flow to the tumor with hypervascular lesions; therefore, a lower sphere count yields potentially higher radiation doses (due to higher specific activity of spheres) to the tumor resulting in improved treatment response.…”

Evaluating therapeutic efficacy of extended shelf-life 90Y glass microspheres in transarterial radioembolization for colorectal cancer: a quantitative FDG PET/CT analysis

“…In this last scientific research, Maxwell et al . concluded that the number of particles/radiomicrospheres delivered can be chosen to maximize the tumor dose and minimize the liver dose [15].…”

“…In a recent study, it has been suggested that optimizing the particle density for TARE, resulted in improved local progression-free survival (PFS) and overall survival (OS). In this last scientific research, Maxwell et al concluded that the number of particles/ radiomicrospheres delivered can be chosen to maximize the tumor dose and minimize the liver dose [15].…”