Effects of Waveform Design on Heat Transfer, Thermal Confinement, and Tissue Damage in Laser Interstitial Thermal Therapy (LITT) for Breast Tumors

• A GDPL-based computational model is developed to study laser interstitial thermal therapy (LITT) in breast tumors. • The effects of pulse number, duty cycle, and waveform smoothing on heating and cooling behavior are systematically analyzed. • Waveform design influences not only peak temperature but also heat distribution and damage to surrounding tissue. • Pulsed energy delivery improves treatment accuracy and reduces damage to surrounding healthy tissue compared to continuous energy delivery. • The results support minimum effective heating as a practical strategy for safer and more selective LITT treatment design. Breast cancer remains one of the most common malignancies among women worldwide, creating a continuing need for treatment strategies that are effective, spatially precise, and minimally invasive. Laser interstitial thermal therapy (LITT) has emerged as a promising focal modality because it enables localized energy deposition and controlled thermally induced tissue destruction. However, treatment outcome depends not only on laser and tissue properties, but also on the temporal pattern of energy delivery. This study developed a computational framework to investigate the thermal response of breast tumor tissue under continuous and pulsed laser irradiation, with emphasis on pulse number, duty cycle, and waveform smoothing. A coupled optical–thermal model was employed to evaluate transient temperature evolution, spatial thermal confinement, and Arrhenius-based thermal damage in both tumor and surrounding healthy tissue. Continuous irradiation produced the most aggressive heating, increasing the tumor-center temperature from 37.00°C to 170.88°C at 176 s. In contrast, pulsed irradiation moderated temperature overshoot; the 1-, 2-, 3-, and 4-pulse cases reached peak temperatures of 132.78°C, 124.72°C, 120.60°C, and 124.97°C, respectively. Among the pulse-number cases, P3 achieved complete tumor damage at 94 s with a healthy-tissue damage fraction of 0.0011515. In the duty-cycle analysis, duty cycle 0.3 ensured complete tumor ablation while yielding the lowest healthy-tissue damage fraction, 0.0010421. These findings support minimum effective heating as a rational principle for safer and more selective laser-based breast tumor treatment planning.