The effects of cavitation position on the velocity of a laser-induced microjet extracted using explainable artificial intelligence

The control of the velocity of a high-speed laser-induced microjet is crucial in applications such as needle-free injection. Previous studies have indicated that the jet velocity is heavily influenced by the volumes of secondary cavitation bubbles generated through laser absorption. However, there has been a lack of investigation of the relationship between the positions of cavitation bubbles and the jet velocity. In this study, we investigate the effects of cavitation bubbles on the jet velocity of laser-induced microjets extracted using explainable artificial intelligence (XAI). An XAI is used to classify the jet velocity from images of cavitation bubbles and to extract features from the images through visualization of the classification process. For this purpose, we run 1000 experiments and collect the corresponding images. The XAI model, which is a feedforward neural network (FNN), is trained to classify the jet velocity from the images of cavitation bubbles. After achieving a high classification accuracy, we analyze the classification process of the FNN. The predictions of the FNN, when considering the cavitation positions, show a higher correlation with the jet velocity than the results considering only cavitation volumes. Further investigation suggested that cavitation that occurs closer to the laser focus position has a higher acceleration effect. These results suggest that the velocity of a high-speed microjet is also affected by the cavitation position.Comment: 11 pages, 13 figures, 4 table

Hemostatic Control with Gelatin Sponge and Quantum Molecular Resonance Coagulation in a Case of Glomus Tympanicum

Surgical removal of tumor is the primary treatment of choice for glomus tympanicum (GT). However, because the tumor has abundant blood flow, bleeding control is crucial, and preoperative embolization may be performed. Here, we report the case of a 46-year-old female who visited our hospital with a complaint of right pulsatile tinnitus. A red pulsatile mass was found in the right tympanic cavity, and she was diagnosed with class B1 GT and subsequently underwent surgical treatment. We judged that bleeding could be controlled by intratympanic cavity manipulation alone and decided to perform transmeatal tumor resection without preoperative arterial embolization. After creating a tympanomeatal flap and performing an atticotomy, some pieces of Spongel® were inserted between the tumor and the tympanic wall. The Spongel® absorbed the blood and created a space between the tumor and tympanic wall, which allowed for the insertion of the tip of the Vesalius® handpiece to coagulate the tumor. The coagulation caused the tumor to shrink, thereby widening the space and allowing for further resection. Although the surgical manipulation caused bleeding, complete resection was achieved by the application of Spongel® and coagulation with Vesalius®. Since the tip of the Vesalius® was not burned, hemostasis was successfully achieved, and the operation proceeded while maintaining a clear field of view. There was little bleeding and no postoperative complications. The patient was discharged on the sixth postoperative day. One year after surgery, pure tone audiometry showed no change in the level of bone conduction. Spongel® and Vesalius® are useful tools that allow to safely perform surgeries even in narrow spaces such as the tympanic cavity