Y-90 Lung Shunt Fraction Calculator
Lung-shunt fraction from Tc-99m-MAA mapping, with management thresholds
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Before Y-90 radioembolization, Tc-99m-MAA mapping estimates how much activity would shunt to the lungs. Enter the lung and liver region counts to compute the lung-shunt fraction (LSF), which — together with your dosimetry model — limits the deliverable activity to keep lung dose within accepted limits (see Y-90 Radioembolization).
Y-90 lung-shunt fraction & lung-dose limit
GBq
kg
Gy
LSF = lung÷(lung+liver). Lung dose (Gy) ≈ 49.67 × A(GBq) × LSF ÷ lung mass(kg). Common caps: ≤30 Gy single / ≤50 Gy cumulative. Max activity = limit × mass ÷ (49.67 × LSF). High LSF reduces deliverable activity.
Evidence & sources
BSNMMI/EANM ⁹⁰Y radioembolization guidance — MAA-derived lung-shunt fraction and lung-dose limits.
INFLung dose depends on the dosimetry model — apply your microsphere-specific method; LSF thresholds here are conventional planning guides.