Material matters: Analysis of density uncertainty in 3D printing and its consequences for radiation oncology
Material matters: Analysis of density uncertainty in 3D printing and its consequences for radiation oncology
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DOI：
10.1002/mp.12839
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发表时间：
2018-04-01
期刊：
影响因子：
3.8
通讯作者：
Howell, Rebecca M.
中科院分区：
文献类型：
--
作者：
Craft, Daniel F.;Kry, Stephen F.;Howell, Rebecca M.
使用3D打印来制造患者特定的设备，如组织补偿器，推注器和体模，价格低廉且相对简单。然而，大多数3D打印材料尚未得到很好的表征，包括它们的放射组织等效性。本研究的目的是（a）确定打印物体的亨氏单位（HU）的方差，（B）确定HU是否随时间变化，以及（c）计算由这些材料变化引起的临床剂量不确定性。在初始打印时和在5周的过程中（标准放射治疗过程的典型时间范围）跟踪平均HU和物理密度。在最初的印刷之后，一半的块被储存在打开的盒子中，另一半被储存在带有干燥剂的密封袋中。评价了四种材料随时间推移的HU和密度方差。使用各种临床光子和电子束来评价作为治疗计划期间所做假设的函数的临床深度剂量的潜在误差。临床深度误差被定义为之间的距离正确计算的90%等剂量线和90%等剂量线计算使用临床合理的，但简化，assumptions.ResultsThe平均HU测量的PLA，ABS，NinjaFlex，和猎豹的个别块变化多达121，30，178，和30 HU，分别。所有材料在5周内的HU变化都要小得多。临床深度误差的大小在很大程度上取决于材料，能量和假设，但有些是大到9.0毫米。结论如果采取适当的质量保证措施，3D打印对象可以准确有效地用于放射治疗。然而，至关重要的是，要很好地理解和说明用于患者护理的任何材料的特性。
PurposeUsing 3D printing to fabricate patient-specific devices such as tissue compensators, boluses, and phantoms is inexpensive and relatively simple. However, most 3D printing materials have not been well characterized, including their radiologic tissue equivalence. The purposes of this study were to (a) determine the variance in Hounsfield Units (HU) for printed objects, (b) determine if HU varies over time, and (c) calculate the clinical dose uncertainty caused by these material variations.MethodsFor a sample of 10 printed blocks each of PLA, NinjaFlex, ABS, and Cheetah, the average HU and physical density were tracked at initial printing and over the course of 5 weeks, a typical timeframe for a standard course of radiotherapy. After initial printing, half the blocks were stored in open boxes, the other half in sealed bags with desiccant. Variances in HU and density over time were evaluated for the four materials. Various clinical photon and electron beams were used to evaluate potential errors in clinical depth dose as a function of assumptions made during treatment planning. The clinical depth error was defined as the distance between the correctly calculated 90% isodose line and the 90% isodose line calculated using clinically reasonable, but simplified, assumptions.ResultsThe average HU measurements of individual blocks of PLA, ABS, NinjaFlex, and Cheetah varied by as much as 121, 30, 178, and 30 HU, respectively. The HU variation over 5 weeks was much smaller for all materials. The magnitude of clinical depth errors depended strongly on the material, energy, and assumptions, but some were as large as 9.0 mm.ConclusionsIf proper quality assurance steps are taken, 3D printed objects can be used accurately and effectively in radiation therapy. It is critically important, however, that the properties of any material being used in patient care be well understood and accounted for.