Utility of Quantitative 99mTc-MAA SPECTCT for 90yttrium-Labelled Microsphere Treatment Planning : Calculating Vascularized Hepatic Volume and Dosimetric Approach

Abstract EN

Objectives.

The aim of this study was to assess the effectiveness of SPECT/CT for volume measurements and to report a case illustrating the major impact of SPECT/CT in calculating the vascularized liver volume and dosimetry prior to injecting radiolabelled yttrium-90 microspheres (Therasphere).

Materials and Methods.

This was a phantom study, involving volume measurements carried out by two operators using SPECT and SPECT/CT images.

The percentage of error for each method was calculated, and interobserver reproducibility was evaluated.

A treatment using Therasphere was planned in a patient with three hepatic arteries, and the quantitative analysis of SPECT/CT for this patient is provided.

Results.

SPECT/CT volume measurements proved to be accurate (mean error <6% for volumes ≥16 cm3) and reproductive (interobserver agreement = 0.9).

In the case report, 99mTc-MAA SPECT/CT identified a large liver volume, not previously identified with angiography, which was shown to be vascularized after selective MAA injection into an arterial branch, resulting in a large modification in the activity of Therasphere used.

Conclusions.

MAA SPECT/CT is accurate for vascularized liver volume measurements, providing a valuable contribution to the therapeutic planning of patients with complex hepatic vascularization.