质子和碳离子治疗中CT值与相对阻止本领转换曲线的测量

Measurement of CT Hounsfield Units and relative stopping powers conversion curve in proton and carbon ion therapy

目的 利用计算机断层扫描设备（CT）及质子重离子装置测量组织等效模体CT值与其对应的相对阻止本领转换曲线。方法 CT值与粒子阻止本领转换曲线在一定程度上决定了剂量计算的准确性。利用12个组织等效模体材料，经计算机断层扫描，获得其对应CT值，再利用质子重离子射线装置的质子、碳离子束流测量这些模体的相对阻止本领，从而获得CT值与质子、碳离子相对阻止本领转换曲线。结果 除肺等效模体以外，其他组织等效模体利用质子和碳离子束流测量得到的相对阻止本领之间的差异≤0.64%。结论 针对质子和碳离子束流，分别建立了基于等效模体测量的CT值-相对阻止本领转换曲线。

Objective To measure the CT Hounsfield Unit （HU） and relative stopping power （RSP） conversion curve.Methods In this study, the RSPs of 12 different tissue equivalent rods were measured with proton and carbon beam in the Shanghai Proton and Heavy Ion Center （SPHIC）. The same tissue equivalent materials were scanned with CT scanner to acquire the HU.Results Conversion curve for the transformation of HU into RSP was generated for both proton and carbon ion beam. Differences between RSPs measured using proton and carbon beam were ≤0.64% except lung material.Conclusions A RSP versus HU conversion curve was generated for both protons and carbon ions.