Factors Modulating 99mTc-MAA Planar Lung Dosimetry for 90Y Radioembolization

Authors

Benjamin P Lopez
Armeen Mahvash
James P Long
Marnix G E H Lam
S Cheenu Kappadath

Publication Date

12-1-2022

Journal

Journal of Applied Clinical Medical Physics

DOI

10.1002/acm2.13734

PMID

35906892

PMCID

PMC9797182

PubMedCentral® Posted Date

7-30-2022

PubMedCentral® Full Text Version

Post-print

Abstract

Purpose: To investigate the accuracy and biases of predicted lung shunt fraction (LSF) and lung dose (LD) calculations via 99m Tc-macro-aggregated albumin (99m Tc-MAA) planar imaging for treatment planning of 90 Y-microsphere radioembolization.

Methods and materials: LSFs in 52 planning and LDs in 44 treatment procedures were retrospectively calculated, in consecutive radioembolization patients over a 2 year interval, using 99m Tc-MAA planar and SPECT/CT imaging. For each procedure, multiple planar LSFs and LDs were calculated using different: (1) contours, (2) views, (3) liver 99m Tc-MAA shine-through compensations, and (4) lung mass estimations. The accuracy of each planar-based LSF and LD methodology was determined by calculating the median (range) absolute difference from SPECT/CT-based LSF and LD values, which have been demonstrated in phantom and patient studies to more accurately and reliably quantify the true LSF and LD values.

Results: Standard-of-care LSF using geometric mean of lung and liver contours had median (range) absolute over-estimation of 4.4 percentage points (pp) (0.9 to 11.9 pp) from SPECT/CT LSF. Using anterior views only decreased LSF errors (2.4 pp median, -1.1 to +5.7 pp range). Planar LD over-estimations decreased when using single-view versus geometric-mean LSF (1.3 vs. 2.6 Gy median and 7.2 vs. 18.5 Gy maximum using 1000 g lung mass) but increased when using patient-specific versus standard-man lung mass (2.4 vs. 1.3 Gy median and 11.8 vs. 7.2 Gy maximum using single-view LSF).

Conclusions: Calculating planar LSF from lung and liver contours of a single view and planar LD using that same LSF and 1000 g lung mass was found to improve accuracy and minimize bias in planar lung dosimetry.

Keywords

Humans, Retrospective Studies, Yttrium Radioisotopes, Tomography, Emission-Computed, Single-Photon, Single Photon Emission Computed Tomography Computed Tomography, Lung, Liver Neoplasms, Embolization, Therapeutic, Microspheres, 90Y radioembolization, 99mTc‐macro‐aggregated albumin, lung dosimetry, planar scintigraphy

Comments

This article has been corrected. See J Appl Clin Med Phys. 2023 Jun 6;24(6):e14017.

Published Open-Access

yes

Recommended Citation

Lopez, Benjamin P; Mahvash, Armeen; Long, James P; et al., "Factors Modulating 99mTc-MAA Planar Lung Dosimetry for 90Y Radioembolization" (2022). Faculty, Staff and Student Publications. 4770.
https://digitalcommons.library.tmc.edu/uthgsbs_docs/4770