Thyroid nodule (TN), a discrete palpable swelling of the thyroid gland, is prevalent among 8% of the adult population. The important concern with these nodules is the differentiation between benign and malignant ones. Since conventional diagnostic techniques (e.g., ultrasound) are not accurate in diagnosis, clinical surgeons adopt to excision biopsy, a golden standard, which requires surgery and removal of the gland. We propose to apply Photoacoustic Spectral Response (PASR), a non-invasive and elasticity based diagnostic technique, onto TN for malignancy diagnosis. In this study, time domain photoacoustic signals were acquired through custom built experimental setup inside the surgical theatre and spectral information were obtained through signal processing. PA spectra could distinguish Follicular Variant of Papillary Thyroid Carcinoma (a thyroid cancer) from the other tissues with a high accuracy which an important challenge in conventional diagnostic techniques. Further, other tissue variants were also successfully differentiated through signal decomposition in a quantitative manner.
We present the development of a laser diode based photoacoustic spectral response (PASR) setup capable of diagnosing human breast cancer tissues through the use of mechanobiological properties of the tissue. A detailed description of the laser driver is provided, highlighting the important characteristics of the developed driver. Furthermore, the amplifier development is described. The developed laser diode based PASR system has been characterized using standard samples. Subsequently, the developed experiment has been applied onto diagnosis of human breast tumors. Energy has been used as a parameter to differentiate between normal and malignant tissues. The results were statistically consistent and then compared with standard histopathology for correlation.
We present a data-acquisition system for a high-power pulsed Nd:glass laser oscillator-amplifier chain. This system includes a number of laser energy monitoring units at various stages of the laser chain, a data-acquisition unit and a control program to control its operation. Each unit in this system is modular and versatile. The system is also capable of working in the presence of high electromagnetic interference, as is found in operation of high-power pulsed Nd:glass laser systems. Any component of this system can be modified independently of the others if the system requirements are changed. The system is ideally suited for lasers with low repetition rate of operation.
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