Preliminary Evaluation of AUC Estimation in Molecular Radiotherapy Using OpenDose and MATLAB CF Toolbox
Chamrern Doeur1, Assyifa Rahman Hakim1, Deni Hardiansyah1*)

1Medical Physics and Biophysics, Physics Department, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, Indonesia, 16424

*) Corresponding author: denihardiansyah[at]ui.ac.id

Abstract

Aim:
This study evaluated the accuracy of OPENDOSE software in calculating the area under the curve (AUC) in molecular radiotherapy, comparing its results with those from the Curve Fitting Tool (CFTool) with model selection in MATLAB.

Methods:
Patient data from the University of Michigan Deep Blue Data Repository (Patients 4 and 6) [1] injected with [177Lu] Lu-DOTATATE with activity of 7.21 GBq (patient 4) and 7.31 GBq (patient 6) were analyzed. Auto-segmented volumes of interest (spleen, kidneys, liver, and vertebrae) were processed in OPENDOSE to derive AUC values. In CFTool, time-activity curves were fitted using exponential models with different parameterization (f2, f3, f3a, and f3b), with model selection based on goodness-of-fit metrics (R2, adjusted R2, SSE, CV) and information criteria (BIC) to get the best exponential model. The best model for each organ was used to compute AUC, and relative deviations (RD) between OPENDOSE and CFTool results were assessed. The RD is considered acceptable if it is under 10% [2].

Results:
We initially concentrated on assessing the RD of the AUC of the function utilized in CFTool following model selection, in comparison to the same function provided in OPENDOSE. In patient 4, the RD for the spleen, right kidney, left kidney, liver, L4, and L3 vertebrae were -0.44%, -0.11%, -0.34%, -0.68%, -0.55%, and -0.53%, respectively. In patient 6, the RD for the right kidney, left kidney, liver, L4, L3, and L2 vertebrae were 0.07%, -0.17%, -0.24%, -0.15%, -0.07%, and -0.01%, respectively.

Conclusion:
When the same fitting models are applied, OPENDOSE and CFTool exhibit a good agreement in AUCs, suggesting that both tools may provide accurate and comparable AUC values in molecular radiotherapy with very minor variations in most organs. This validation supports OPENDOSE as a reliable tool for dosimetry in molecular radiotherapy.

References:
[1] Dewaraja, YK., Van, BJ. (2021)
[2] Hardiansyah D, et al. (2024)

Keywords: Keywords: AUC, CFTool, Molecular radiotherapy, OPENDOSE

Topic: Medical Physics and Biophysics