Personalized predictive lung dosimetry by technetium-99m macroaggregated albumin SPECT/CT for yttrium-90 radioembolization

Yung Hsiang Kao; Butch M Magsombol; Ying Toh; Kiang Hiong Tay; Pierce Kh Chow; Anthony Sw Goh; David Ce Ng

doi:10.1186/s13550-014-0033-7

Personalized predictive lung dosimetry by technetium-99m macroaggregated albumin SPECT/CT for yttrium-90 radioembolization

EJNMMI Res. 2014 Jun 29:4:33. doi: 10.1186/s13550-014-0033-7. eCollection 2014.

Authors

Yung Hsiang Kao¹, Butch M Magsombol², Ying Toh², Kiang Hiong Tay³, Pierce Kh Chow⁴, Anthony Sw Goh², David Ce Ng²

Affiliations

¹ Department of Nuclear Medicine and PET, Singapore General Hospital, Outram Road, Singapore 169608, Singapore ; Department of Nuclear Medicine, Austin Hospital, Level 1, Harold Stokes Building, 145 Studley Rd, Melbourne 3084, Victoria, Australia.
² Department of Nuclear Medicine and PET, Singapore General Hospital, Outram Road, Singapore 169608, Singapore.
³ Department of Diagnostic Radiology, Singapore General Hospital, Outram Road, Singapore 169608, Singapore.
⁴ Department of General Surgery, Singapore General Hospital, Outram Road, Singapore 169608, Singapore ; Department of Surgical Oncology, National Cancer Centre Singapore, 11 Hospital Drive, Singapore 169610, Singapore ; Office of Clinical Sciences, Duke-National University of Singapore Graduate Medical School, 8 College Rd, Singapore 169857, Singapore.

Abstract

Background: For yttrium-90 ((90)Y) radioembolization, the common practice of assuming a standard 1,000-g lung mass for predictive dosimetry is fundamentally incongruent with the modern philosophy of personalized medicine. We recently developed a technique of personalized predictive lung dosimetry using technetium-99m ((99m)Tc) macroaggregated albumin (MAA) single photon emission computed tomography with integrated CT (SPECT/CT) of the lung as part of our routine dosimetric protocol for (90)Y radioembolization. Its rationales are the technical superiority of SPECT/CT over planar scintigraphy, ease and convenience of lung auto-segmentation CT densitovolumetry, and dosimetric advantage of patient-specific lung parenchyma masses.

Methods: This is a retrospective study of our pulmonary clinical outcomes and comparison of lung dosimetric accuracy and precision by (99m)Tc MAA SPECT/CT versus conventional planar methodology. (90)Y resin microspheres (SIR-Spheres) were used for radioembolization. Diagnostic CT densitovolumetry was used as a reference for lung parenchyma mass. Pulmonary outcomes were based on follow-up diagnostic CT chest or X-ray.

Results: Thirty patients were analyzed. The mean lung parenchyma mass of our Southeast Asian cohort was 822 ± 103 g standard deviation (95% confidence interval 785 to 859 g). Patient-specific lung parenchyma mass estimation by CT densitovolumetry on (99m)Tc MAA SPECT/CT is accurate (bias -21.7 g) and moderately precise (95% limits of agreement -194.6 to +151.2 g). Lung mean radiation absorbed doses calculated by (99m)Tc MAA SPECT/CT and planar methodology are both accurate (bias <0.5 Gy), but (99m)Tc MAA SPECT/CT offers better precision over planar methodology (95% limits of agreement -1.76 to +2.40 Gy versus -3.48 to +3.31 Gy, respectively). None developed radiomicrosphere pneumonitis when treated up to a lung mean radiation absorbed dose of 18 Gy at a median follow-up of 4.4 months.

Conclusions: Personalized predictive lung dosimetry by (99m)Tc MAA SPECT/CT is clinically feasible, safe, and more precise than conventional planar methodology for (90)Y radioembolization radiation planning.

Keywords: CT lung densitovolumetry; Lung mass; Partition model; Selective internal radiation therapy; Technetium-99m macroaggregated albumin SPECT/CT; Yttrium-90 radioembolization.