形态学处理在肿瘤体积测量中的可行性分析

目的:基于CT图像,通过形态学处理软件C半自动化测量模型容积并与真实容积比较,验证该软件的有效性。方法:7个中空模型容积介于1.93～64.75ml,灌满16.6%的甘露醇溶液后,固定在水桶底座,水桶灌满水后,采集CT图像,测量模型壁厚度、CT值,以及16.6%的甘露醇溶液、水与空气的CT值。设空气/水,水/模型壁,空气/模型壁界面的CT值阈值分别是-20HU,16HU,-900HU。根据模型壁厚度自适应测量模型容积,并计算测量相对误差。结果:这7个模型壁厚从0.6～3.5mm不等,壁CT值(58.1±5.2)～(116.8±4.7)HU。模型内16.6%甘露醇溶液CT值(47.8±4.6)HU,水桶内水CT值(-2.6±4.2)HU,空气CT值(-1 002.4±2.4)HU。7个模型容积测量值容积从2.15～68.40ml,测量相对误差(-2.0±9.0)%。结论:形态学处理软件C能够测量模型容积,其准确性受限于CT图像的空间分辨率。

Tumor Volume Assessment by Morphological Image Processing-a Feasibility Analysis

Objective:A morphological image processing software C was established to semi-automatic outline a tumor based on computed tomography(CT) for oncologist.Volumes of a set of tumor phantom were assessed by software C,compared with the true volumes of them to test the efficiency of it.Methods:Seven hollow models were filled with 16.6% mannitol,fixed on the bottom of a barrel filled with water.The set of models spanning from 1.93ml to 64.75ml were scanned by CT(Discovery ST8,GE).The hounsfield units(HU) of walls of models,16.6% mannitol,water,and air,and the thickness of models’wall were measured by Matlab 2007b(Mathworks Ins.USA).-20HU,16HU,and-900HU were set as threshold value for air/water,water/wall of models,and air/wall of models.The volume of a model was computed by the total voxel number inside of the model multiplied by the volume of voxel.The relative error of a model was computed.Results:The thickness of models’wall ranged from 0.6mm to 3.5mm.The HU of models’wall were ranged from(58.1±5.2) to(116.8±4.7)HU.The HU of 16.6% mannitol,water,and air was(47.8±4.6)HU,(-2.6±4.2)HU and(-1 002.4±2.4)HU,respectively.The volumes of these models measured were spanning from 2.15ml to 68.40ml.The relative error was(-2.0±9.0)%,ranged from-16.4% to 11.4%.Conclusion:The software C could semi-automatically assess the volume of a model.The accuracy of assessment was limited by the resolution of CT images.