scholarly journals The dosimetric impact of stabilizing spinal implants in radiotherapy treatment planning with protons and photons: standard titanium alloy vs. radiolucent carbon‐fiber‐reinforced PEEK systems

2020 ◽  
Vol 21 (8) ◽  
pp. 6-14
Author(s):  
Birgit S. Müller ◽  
Yu‐Mi Ryang ◽  
Markus Oechsner ◽  
Mathias Düsberg ◽  
Bernhard Meyer ◽  
...  
Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7469
Author(s):  
Haipeng Wang ◽  
Peng Yan ◽  
Yingchun Guan

The development of heterojunctions with a strong bonding interface between metals and non-metals has attracted much attention owing to their great potential for use in lightweight structures. Laser joining technology, which emerged as a fast and reliable method, has proven its feasibility and unique advantages in joining metal to polymer matrix composites. Herein, an optimized laser joining configuration has been employed to realize high-quality joining of titanium alloy and carbon fiber-reinforced composite. Cross-sectional microstructures of laser-produced joints reveal that micro-bubbles near the interface have been effectively suppressed and eliminated due to the continual clamping pressure applied to the joined area during the joining process. Tensile tests suggest that the joint strength increases with structure density on a titanium alloy surface, and the greatest fracture strength of joints reaches more than 60 MPa even after experiencing a high–low temperature alternating aging test. For higher structure density (>95%), the joints fail by the fracture of parent plastics near the joined area due to the tensile-loading-induced peel stress at the edges of the overlap region. Otherwise, the joints fail by interfacial shear fracture with breakage when the structure density is lower than 91.5%. The obtained high-performance heterojunctions show great potential in the aerospace and automotive fields.


2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Richard C. Petersen

Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis.In vivobone-marrow tests with Sprague-Dawley rats revealed far-reaching significant osseoconductivity increases from bisphenyl-polymer/carbon-fiber composites when compared to state-of-the-art titanium-6-4 alloy controls. Midtibial percent bone area measured from the implant surface increased when comparing the titanium alloy to the polymer composite from 10.5% to 41.6% at 0.8 mm,P<10−4, and 19.3% to 77.7% at 0.1 mm,P<10−8. Carbon-fiber fragments planned to occur in the test designs, instead of producing an inflammation, stimulated bone formation and increased bone integration to the implant. In addition, low-thermal polymer processing allows incorporation of minerals and pharmaceuticals for future major tissue-engineering potential.


2014 ◽  
Vol 620 ◽  
pp. 42-48 ◽  
Author(s):  
Chuang Huang ◽  
Xiao Wang ◽  
Yan Wei Wu ◽  
Dong Dong Meng ◽  
Hui Xia Liu

This paper presents an experimental study to evaluate the feasibility, characteristics and mechanism of laser direct joining between metal and carbon fiber reinforced plastic (PA66CF20). This study presents a method to improve the joint strength of the metal-polymer hybrid joint. The investigation study effects of process parameters (laser power and travelling speed) on the quality of joining joint. Macroscopic morphology of joint and PA66CF20 melting region closed to the interface were observed in this study. XPS analysis shows that Ti-C and Ti-O chemical bonding were produced between titanium alloy and plastic. Cross-sectional photo showed the melted polymer flowed into micro-cavity of metal surface caused by roughness of metal and thus formed mechanical bonding. Finally, the titanium alloy surface was structured in four different surface textures using a pulsed laser. Then the metal was joined with the plastic. The result shows that the joint strength of metal after laser-structured joining with plastic had been improved greatly.


2021 ◽  
Vol 50 (5) ◽  
pp. E13
Author(s):  
Matthew T. Neal ◽  
Alexandra E. Richards ◽  
Kara L. Curley ◽  
Naresh P. Patel ◽  
Jonathan B. Ashman ◽  
...  

OBJECTIVE The authors aimed to demonstrate the feasibility and advantages of carbon fiber–reinforced PEEK (CFRP) composite implants in patients with both primary and secondary osseous spinal tumors. METHODS Twenty-eight spinal tumor patients who underwent fixation with CFRP hardware were retrospectively identified in a Spine Tumor Quality Database at a single institution. Demographic, procedural, and follow-up data were retrospectively collected. RESULTS The study population included 14 females and 14 males with a mean age of 60 years (range 30–86 years). Five patients had primary bone tumors, and the remaining patients had metastatic tumors. Breast cancer was the most common metastatic tumor. The most common presenting symptom was axial spine pain (25 patients, 89%), and the most common Spine Instability Neoplastic Score was 7 (range 6–14). Two patients in this series had anterior cervical procedures. The remaining patients underwent posterior thoracolumbar fixation. The average fusion length included 4.6 vertebral segments (range 3–8). The mean clinical follow-up time with surgical or oncology teams was 6.5 months (range 1–23 months), and the mean interval for last follow-up imaging (CT or MRI) was 6.5 months (range 1–22 months). Eighteen patients received postoperative radiation at the authors’ institution (16 with photon therapy, 2 with proton therapy). Eleven of the patients (39%) in this series died. At the last clinical follow-up, 26 patients (93%) had stable or improved neurological function compared with their preoperative status. At the last imaging follow-up, local disease control was observed in 25 patients (89%). Two patients required reoperation in the immediate postoperative period, one for surgical site infection and the other for compressive epidural hematoma. One patient was noted to have lucencies around the most cephalad screws 3 months after surgery. No hardware fracture or malfunction occurred intraoperatively. No patients required delayed surgery for hardware loosening, fracture, or other failure. Early tumor recurrence was detected in 3 patients. Early detection was attributed to the imaging characteristics of the CFRP hardware. CONCLUSIONS CFRP spinal implants appear to be safe and comparable to conventional titanium implants in terms of functionality. The imaging characteristics of CFRP hardware facilitate radiation planning and assessment of surveillance imaging. CFRP hardware may enhance safety and efficacy, particularly with particle therapy dosimetry. Larger patient populations with longer-term follow-up are needed to confirm the various valuable aspects of CFRP spinal implants.


2020 ◽  
Vol 40 (10) ◽  
pp. 868-875
Author(s):  
Hongyan Yang ◽  
Xiaohong Zhan ◽  
Hengchang Bu ◽  
Wanping Ma ◽  
Feiyun Wang

AbstractLaser direct joining of carbon fiber reinforced thermoplastic (CFRTP) composite plate and titanium alloy plate with a thickness of 2 mm was performed with swing laser. Numerous air bubble of submillimeter size were observed inside the fusion zone of CFRTP and titanium alloy at the cross section of the joints. The air bubble characteristics were analyzed based on the morphology and size, while the formation mechanism of air bubble was further elucidated according to the nucleation mode, nucleation site and nucleation position. The results demonstrated that the nucleation modes of air bubble are substantially divided into homogeneous nucleation and heterogeneous nucleation, which is related to the nucleation sites. The nucleation mode presents a crucial factor influencing the position and morphology of air bubble. In addition, the air bubble characteristics are also determined by the clamp pressure and resin flow. The final morphology of air bubble is primarily represented by four typical types.


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