Laparoscopic Ultrasound-guided I¹²⁵ Implantation In The Treatment Planning Of Pancreatic Cancer

This paper is focused on the research of laparoscopic ultrasound-guided I¹²⁵implantation and a novel method,laparoscopic ultrasound-Guided I¹²⁵ implantation in the treatment planning of pancreatic cancer by virtual template based on the surface of the tumor,is proposed.Primary contents of this research include three-dimensional representations of the tumor and surrounding organs,generation of the virtual template on the basis of the tumor,three-dimensional dose planning.The main research works and innovations in this paper are as follows:Firstly,the three-dimensional reconstruction of the tumor and surrounding organs based on laparoscopic ultrasound are accomplished.According to the need of pancreatic cancer brachytherapy,the image is segmented into different regions by regional growth algorithm and manual segmentation;and then,Marching Cubes algorithm combined with Laplace method is applied to the fast reconstruction of multiple organs.Eventually,the reconstruction results dedicates high precision virtual human tissue model.Secondly,the advantages and disadvantages of close seed implantation by the traditional template are analyzed.And the close seed implantation combined with virtual template based on the tumor is proposed.The surgical method of laparoscopic ultrasound-guided close seed implantation is studied and the meshes of the virtual template is described in detail.Then the virtual template provides both the position and the number of puncture needles.The orientation of needles are more flexible and the rationality of dose distribution is ensured.Finally,the three-dimensional dose planning is proposed.The model of radiation dose calculation is introduced.And the result of the treatment planning is assessed by the dose volume histogram,while the V100 of the tumor and the pancreas are 92.83%and 0.40%respectively satisfying the clinical dose requirements.The feasibility of this technology is verified.CT images of a pancreatic cancer patient were transmitted to accomplish the preoperative planning of laparoscopic ultrasound-guided I¹2525 implantation,and the results of this method was evaluated.It’s showed that laparoscopic ultrasound-guided implantation of I¹²⁵ seeds can be considered as a useful method for treating pancreatic cancer with accurate implantation of I¹²⁵ seeds and satisfying effect of local control for the tumor.