Clinicians at the达纳 - 法伯癌研究所,Brigham and Women’s Hospital,Massachusetts General Hospital， 和MIThave developed a novel 3D printed shielding that protects the healthy tissues of cancer patients during radiotherapy.
Using patient CT scans and high atomic number materials, the team has been able to 3D print customized devices that prevent gamma and X-ray-induced radiation toxicity in gastrointestinal or oral tissues. If used to treat head, neck, or prostate cancer patients, the scientists believe that their shielding could help reduce radiation of the mouth and stomach by up to 30% and 15% respectively, without lowering the dosage to the tumor.
“当我们治疗辐射患者时，这是一个很好的平衡。我们希望服用最大的剂量来缩小肿瘤，而不会损害健康组织。“我们通过该项目的目标是找到一种创新的解决方案，可以为患者提供个性化保护。”
“这种个性化方法可能适用于各种癌症，并具有减轻对患者的辐射损伤和毒性负担的潜力。”
Treating radiation toxicity
Statistically, more than half of all cancer patients will undergo some form of radiation therapy, but while the treatment is effective at killing tumor cells, it can also cause toxicity to otherwise healthy tissues. In the U.S. alone, more than 200,000 patients suffer from radiation-induced oral mucositis, esophagitis, and proctitis each year, sometimes in severe enough bouts to cause them to discontinue their treatment altogether.
Currently, doctors tend to use physical spacers in an attempt to prevent mucositis, but these often offer limited protection, and can even lead to additional side effects. In order to reduce radiation therapy’s morbidity without limiting its efficacy, the team has therefore identified the need for patient-specific shielding that makes treatment more palatable, thus improving patient adherence and ultimately their chances of survival.
“It’s not uncommon for gastroenterologists to be called in to consult on a case to support a patient who is experiencing side effects of radiation in the esophagus, small intestine, or anywhere else in the gastrointestinal tract,” said study co-author Giovanni Traverso. “A couple of years ago, James and I began brainstorming — what if we could develop a shield that could help protect a significant portion of normal tissue in the radiation field?”
Radioprotectant 3D printing
鉴于辐射诱导的毒性通常在口腔，肺和前列腺癌患者中最高，因此临床研究人员选择开发专门设计用于保护这些地区组织的屏蔽。但是，在他们可以设置大约3D打印放射性保护设备之前，科学家需要确定任务的最佳“高Z材料基础”。
Initial testing, which involved exposing various alloys and plastics to 6 MV photon radiation, revealed that elemental materials provided the highest attenuation, leading the team to develop a lead and bismuth-loaded resin. Once they’d formulated their feedstock, the scientists utilized diagnostic ‘DICOM’ CT scans to create accurate 3D models of the mouths, intestines, and rectums of multiple different lab rats.
有趣的是，最终的模型揭示了测试患者解剖学的巨大差异，并允许科学家个性化每个设备，使其舒适的插入以及优化其辐射保护。然后使用formlabsForm 2 3D printer, and inserted orally into seven specimens, with the aim of protecting 50% of the tissue that’s normally at risk of radiotoxicity.
虽然七只未屏蔽的大鼠出现了辐射引起的舌溃疡，但七个受保护的测试受试者根本没有副作用。在以后的实验中，将类似的口腔内，食管和直肠装置插入猪标本中，这些标本可将肠道辐射降低15％，并在口服颊粘膜内的毒性降低30％，而不会对肿瘤剂量造成影响。
与常规的水凝胶垫片相比，临床医生还算出，其设备的成本降低了40％，同时提供了相同的功效。结果，该团队得出结论，尽管在屏蔽可以进入人类试验之前需要进一步评估，但他们的概念仍可以在将来看到最终使用，作为减少各种不同癌症患者的放射治疗的副作用的一种手段。
“Personalized 3D printed radioprotectant devices may have great potential to reduce radiation toxicity in clinical settings,” concluded the researchers in their paper. “This personalized approach could be applicable to a variety of cancers that respond to radiation therapy, including head and neck, lung, prostate, anal, skin, and gynecological cancers, sarcomas and lymphomas.”
3D印刷癌症设备
By combining 3D printing and scanning technologies, it’s now easier than ever to produce patient-specific devices that ease the suffering of those undergoing cancer treatment. Scientists at thePohang University of Science and Technology（Postech）已开发3D打印的食管支架, which are designed to ease dysphagia in radiotherapy patients.
In the future, the POSTECH team believes that their devices could be loaded with cells to treat tissue-specific inflammation or be used to address everyday injuries such as cuts or burns. In a similar vein,适应医学技术软件经常部署到3D打印肿瘤设备，能够调节辐射剂量以说明患者组织缺失。
Elsewhere, additive manufacturing is also being used by scientists atHanyang University创造高效伽马辐射探测器。During testing, the team’s novel device has demonstrated a similar decay time and intrinsic detection efficiency to a commercial scintillator, lending it potential applications in areas where rapid detection is needed.
The researchers’ findings are detailed in their paper titled “Personalized Radiation Attenuating Materials for Gastrointestinal Mucosal Protection。”
The research was co-authored by James D. Byrne, Cameron C. Young, Jacqueline N. Chu, Jennifer Pursley, Mu Xian Chen, Adam J. Wentworth, Annie Feng, Ameya R. Kirtane, Kyla A. Remillard, Cindy I. Hancox, Mandar S. Bhagwat, Nicole Machado, Tiffany Hua, Siddartha M. Tamang, Joy E. Collins, Keiko Ishida, Alison Hayward, Sarah L. Becker, Samantha K. Edgington, Jonathan D. Schoenfeld, William R. Jeck, Chin Hur and Giovanni Traverso.
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Featured image shows a diagram of the researchers’ 3D printed shielding in action. Image via Giovanni Traverso.
