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SIR 2026

Scientific Session

Late-breaking Abstract

Interventional Oncology

Session: Late-breaking Abstracts 1

A Dosimetry Framework for Lung Cancer Cryoablation : A Multiscale In Vitro and Clinical Experiment

Sunday, April 12, 2026
4:12 PM - 4:21 PM ET
Location: 718B
Purpose:

Cryoablation margin guidelines recommend treating to the -40°C, -20°C, or 0°C isotherm, yet these thresholds lack systematic experimental validation and biological rationale. Freeze-thaw cycle protocols also remain empirical, a limitation underscored in our recent metanalysis {1}. This absence of dosimetric data risks overtreatment with extended adverse events or undertreatment with marginal recurrence. This study presents a multiscale experimental platform to establish an evidence-based dose-response relationship for lung cancer cryoablation.

Materials and Methods:

Lung adenocarcinoma cells (Calu-1, A549) were used in stepwise experiments. 2D monolayer studies (N=3) established thermal-biological correlations using a clinical cryoprobe. 3D experiments (N=3) used 1cm³ engineered tissue constructs in a custom 3D-printed biocompatible scaffold with a guide plate for reproducible cryoprobe and thermocouple positioning. Continuous temperature monitoring at 7 radial positions (probe tip to 14.4mm) enabled direct co-registration of thermal history with cell fate: acute viability (Calcein-AM/Propidium Iodide) and apoptosis (Cleaved Caspase-3 immunofluorescence). Exponential thermal decay and sigmoidal cell death models were derived and integrated into a COMSOL Multiphysics simulation (R²=0.96), currently undergoing retrospective validation against clinical outcomes.

Results:

Temperature followed a predictable exponential decay (R²=0.99). In monolayers, cell death exhibited sigmoidal temperature-dependence (r=-0.85, p< 0.001), with maximum lethality (96.6% cell death) plateauing under -4.5 °C, and with 92.9 % lethality at 0 °C. Of note, cell death at -20 °C and below was equivalent (96.7 %), suggesting these isotherms may represent overtreatment without additional cytotoxic benefit. CC3 analysis in 3D constructs revealed a distinct apoptotic transition zone at 5-28 °C (p < 0.05), potentially representing delayed death in tissue appearing viable on immediate post-procedural imaging.

Conclusion:

This study introduces the first experimentally-derived dosimetry framework for lung cancer cryoablation. A lethal plateau was achieved by -4.5°C, with no measurable improvement over clinically-recommended colder temperatures. In addition, an apoptotic transition zone extending into warmer tissue suggests potential delayed tumoricidal effects not captured by ice ball margin assessment. Combined with computational modeling, these findings provide the foundation for predictive, patient-specific treatment planning in lung cryoablation.