Optimizing TMS Coil Placement Approaches for Targeting the Dorsolateral Prefrontal Cortex in Depressed Adolescents: An Electric Field Modeling Study

High-frequency repetitive transcranial magnetic stimulation (rTMS) to the left dorsolateral prefrontal cortex (L-DLPFC) shows promise as a treatment for treatment-resistant depression in adolescents. Conventional rTMS coil placement strategies include the 5 [Formula: see text] , the Beam F3, and the magnetic resonance imaging (MRI) neuronavigation methods. The purpose of this study was to use electric field (E-field) models to compare the three targeting approaches to a computational E-field optimization coil placement method in depressed adolescents. Ten depressed adolescents (4 females, age: [Formula: see text]) participated in an open-label rTMS treatment study and were offered MRI-guided rTMS five times per week over 6–8 weeks. Head models were generated based on individual MRI images, and E-fields were simulated for the four targeting approaches. Results showed a significant difference in the induced E-fields at the L-DLPFC between the four targeting methods ([Formula: see text] , [Formula: see text]). Post hoc pairwise comparisons showed that there was a significant difference between any two of the targeting methods (Holm adjusted [Formula: see text]), with the 5 [Formula: see text] rule producing the weakest E-field ([Formula: see text]), followed by the F3 method ([Formula: see text]), followed by MRI-guided ([Formula: see text]), and followed by the computational approach ([Formula: see text]). Variance analysis showed that there was a significant difference in sample variance between the groups ([Formula: see text] , [Formula: see text]), with F3 having the largest variance. Participants who completed the full course of treatment had median E-fields correlated with depression symptom improvement ([Formula: see text] , [Formula: see text]). E-field models revealed limitations of scalp-based methods compared to MRI guidance, suggesting computational optimization could enhance dose delivery to the target.