Research On Extraction Of Thoracic Anatomy And Path Planning Based On Lung Puncture Surgical Navigation

Lung cancer is the number one killer-cancer with high death rate,lung biopsy technique which is guided by the CT images as the most conventional method for lung tumor detection is widely used in clinical surgery.But it may have the problems that with much radiation dose and more times of puncture,which may lead to the occurrence of adverse complications.Lung puncture technique based on surgical navigation system not only can improve the above problems,but also can greatly improve the success rate of puncture and reduce the injury of patients.As the basis of surgical navigation,preoperative image segmentation of organs in chest and puncture path planning is particularly important,it will be used as an important reference to guide doctors do the surgery.The segmentation of the organs in chest and the puncture path planning are the two main research contents in this paper.The segmentation of organs in chest can be divided into the following aspects:1)According to the operating characteristics of lung puncture surgery,the research about the organs and tissue that need to be avoided during the operation is done.After that,we know their actual position and features in the image.Then the segmentation method is determined according to the characters of each organs and tissue since a lot of literature about them is consulted.2)In this thesis,a fast and automated multi-organ segmentation method is proposed to segment the vital organs such as skin,trachea,lung parenchyma,bone,vessels,interlobar fissure and mediastinum.3)The accuracy of the result of segmentation is verified since the vital organs and tissue are segmented in the previous step.The validation method used in this paper is to compare the result of segmentation using the segmentation method with the "gold standard" that provided by the doctor from 3 indicators:the coincidence degree,the false positives and false negatives.The result of the comparison will tell whether the segmentation method is reasonable.Next,the research of path planning based on the lung puncture surgery navigation can be divided into three aspects:1)In this paper,the unreasonable puncture point is removed using hard conditions,the hard conditions include the following three parts:the path length should be within the scope of the puncture needle,puncture path cannot pass important organs and tissues,and the puncture angle is not greater than a given threshold.The puncture points that can not meet the 3 conditions will be removed.2)The characteristic values of the remaining data is obtained.The characteristic values of the data include:the total length of the path,the length of the path in lung,the insert angle,the distance to vital organs and the extension distance to vital organs.They are used as soft constraints.Based on the medical knowledge and the characteristic values,a model is established.Two different methods include risk weighting and pareto optimal are used to do the puncture path planning.3)After the comparison between the real path and the path that calculate by the model.The doctor will judge whether the path that calculate by the model is reasonable.Finally,the path that calculate by the model meet the requirement of the surgery,the path can play great guiding signification in lung puncture operation,which improve the accuracy of puncture in lung biopsy puncture surgery navigation system.