Diode Laser-Based Photoacoustic Imaging for the Features of Benign and Malignant Uterine Tumors

Introduction: Photoacoustic imaging (PAI) uses nonionizing radiation for tumor features and thus can be used as an alternative method for medical features without inducing biological effects. The study aimed to characterize a PAI system utilizing a 650-nm diode laser to detect pathological conditions (benign and malignant tumors) in human uterine tissue, including healthy tissue. The benign tumor tissue used is a leiomyoma, which is a benign tumor that occurs in the middle layer of the uterine (myometrium). Meanwhile, the malignant tumor tissue used is a type of endometrial carcinoma, which is a malignant tumor that occurs in the inner layer of the uterine (endometrium). Methods: The human uterine tissue was obtained from the hysterectomy procedure conducted to determine the histopathological diagnosis. The PAI system uses a condenser microphone as the acoustic signal detector and a diode laser as the radiation source. Results: The characterization results of the PAI based on a diode laser with a wavelength of 650 nm and power of 250 mW showed an optimal performance for human uterine tissue in a laser modulation frequency of 16500 Hz and a duty cycle of 50%. Obtained photoacoustic images could differentiate between healthy uterine, leiomyoma, and endometrial carcinoma tissues, as indicated by the intensity level values in each tissue type. Healthy uterine, leiomyoma, and endometrial carcinoma tissues had intensity values of 11.87, 26.84, and 37.26 a.u, respectively. A One-way ANOVA test with Bonferroni post hoc analysis revealed a significant difference in the acoustic intensity level between the groups (P<0.05). Conclusion: The resulting intensity levels indicate a direct correlation with the nature of uterine tumors. The poorer the differentiation, the higher the resulting intensity.