等效组织材料聚氯乙烯的医学成像特性

Medical imaging properties of tissue equivalent material of polyvinyl chloride

目的:聚氯乙烯树脂(PVC)的光学透明性和硬度与真实组织接近,适用于作为等效组织材料应用于医学领域,本研究旨在探讨不同PVC-增塑剂(对苯二甲酸二辛酯,DOTP)混合比与医学成像特性(如X线衰减系数、CT值和MRI弛豫时间)的关系。方法:不同PVC-DOTP混合比会影响材料的医学成像特性。本实验制作11组不同混合比的PVC聚合物样品,通过测量各组PVC聚合物样品的CT值和MRI弛豫时间,对PVC材料的成像特性进行评估;同时随机抽取5组PVC聚合物样品在不同电压下测量X线衰减系数。结果:当PVC-DOTP混合比范围为8.0×10^-2~23.3×10^-2g/mL时,测得平均CT值范围为-0.6~109.0HU,T1弛豫时间为172.3~203.9ms,T2弛豫时间为13.7~32.1ms;在电压为40~120kV时,样品的X线衰减系数的范围为6~20.8m^-1。结论:PVC聚合物具有可控的CT值和MRI弛豫时间,透光度好,具有一定的粘弹性,可以作为组织等效材料制作医用体模。

Objective Polyvinyl chloride(PVC)which had similar optical transparency and hardness with those of human tissues is suitable for medical applications as tissue equivalent materials.The purpose of this study is to investigate the relationships between different PVC-softener(dioctyl terephthalate,DOTP)mixture ratios and the medical imaging characteristics(such as X-ray attenuation coefficient,CT number and MRI relaxation time).Methods The medical imaging properties of the materials were affected by different PVC-DOTP mixture ratios.Therefore,11 groups of PVC samples with different mixture ratios were prepared in the study.The medical imaging properties of PVC materials were evaluated by measuring the CT number and MRI relaxation time of PVC samples.Meanwhile,the X-ray attenuation coefficients of 5 groups of PVC samples at different voltages were also measured.Results When the PVC-DOTP mixture ratio ranged from 8.0×10^-2 to 23.3×10^-2 g/mL,the corresponding average CT number was-0.6 to 109.0 HU,and the T1 and T2 relaxation time was 172.3-203.9 ms and 13.7-32.1 ms,respectively.At the voltage of 40-120 kV,the X-ray attenuation coefficient of the samples was 6.0-20.8 m^-1.Conclusion PVC which has controllable CT number and MRI relaxation time,with the advantages of good light transmittance and a certain degree of viscoelasticity,can be used as the tissue equivalent material for medical phantom.