Research On Polyvinyl Chloride And 3D Printing Techniques To Creat A Multi-modalities Breast Phantom For Quality Control

PurposeBreast imaging technology is increasingly important for breast cancer treatment paradigms.Different imaging methods have different manifestations of breast lesions,such as display,density and signal.Therefore,the development of multi-purpose breast phantoms is vital for quantitative and qualitative evaluation with multi-modal imaging platforms.The purpose of this article is:1.To investigate the mechanical properties（e.g.Poisson ratio and elastic modulus）and medical imaging properties（e.g.X-ray attenuation coefficient,computed tomography（CT）number and magnetic resonance imaging（MRI）relaxation time）of polyvinyl chloride（PVC）based tissue-mimi-cking materials（TMMs）with different PVC-softener ratios.2.Combine PVC-based TMMs and three-dimensional（3D）printing technology,multimodalities breast phantom was constructed for mammography,MRI and ultrasound imaging.3.The breast phantom cooperates with the quality control（QC）inserts was used to evaluate different modalities images quantitatively and qualitatively,and to compare the different manifestations of breast lesions under different modalities.Materials and Method1.The PVC-based TMM sample consists of a mixture of PVC powder and softener（dioctyl terephthalate）.The medical imaging properties（e.g.X-ray attenuation coefficient,CT number and MRI relaxation time）and mechanical properties（e.g.Poisson ratio and elastic modulus）are varied by adjusting the PVC-softener ratios.In this experiment,10groups of PVC samples with different PVC-softener ratios were prepared.It was used to study the variation of X-ray attenuation coefficient,CT number and MRI relaxation time with the change of PVC-softener ratios.In order to study the mechanical properties of PVC,three groups of PVC samples with different PVC-softener ratios(10.9×10^-2,13.8×10^-2 and16.7×10^-2 g/mL)were selected for tensile test.2.Based on the medical imaging properties of PVC and 3D printing technology,the multimodalities breast phantom was constructed.The multi-modalities breast phantom was scanned by mammography,MRI and ultrasound imaging.and the original medical digital imaging and communication in medicine（DICOM）data were obtained.3.Embedded QC inserts with different functions was contained in breast phantom,including tumor insert,depth resolution insert,fiber insert and microcalcification insert.The images were read by radiologists in different fields（mammography,MRI and ultrasound）.4.The evaluation results were recorded to compare the performance of the embedded QC inserts with different functions in different modality.Results1.When PVC-softener ratio is in the range of 7.9×10^-2-23.1×10^-2 g/mL,CT numbers varied over a range of approximately-10 to 110 HU.And the relaxation times of the T1-weighted and T2-weighted images were 118.30-283.18 ms and 10.34-36.25 ms,respectively.The elastic moduli ranged from 7.000-12.376 MPa,and Poisson ratios were0.604-0.644.2.The multi-purpose breast phantom had an average background value of 36.2 HU,which is close to that of glandular breast tissue（40 HU）.T1 and T2 relaxation times had an average relaxation time at 206.81±17.50 and 20.22±5.74 ms,respectively.3.Compared with ultrasound and MRI with multiple sequences（T1WI,T2WI and STIR）,mammographic imaging improved the detection of microcalcification.Soft-tissue lesion detection and cylindrical tumor contrast were superior with mammography and MRI compared to ultrasound.Hemispherical tumor detection is similar regardless of imaging modality.Conclusion1.The TMM（i.e.,PVC）in this study is easy to be manufactured or duplicated,and has the advantages of plasticity and long shelf life.It can be scanned under mammography,CT and MRI.Thus,it can be applied as TMM to medical phantom.2.Combined with medical imaging properties of PVC-based TMMs and 3D printing technology,the shape similarity and internal structure simulation of the phantom and human organs or tissues can be realized.3.Combined with multi-modalities phantom and multi-functional QC inserts can using quantitative and qualitative analysis for the detection of different modalities on breast lesions.