The Development of a Composite Thin Film Barrier of Tungsten Fe3O4-rGO (FerGO) for the Radiation Shielding of Medical Personnel.

Tungsten is the most effective eco-friendly material used for radiation shielding in hospitals. However, despite its commendable density and shielding performance, tungsten faces challenges in miscibility with other materials because of its elevated melting point and strength. In this study, to protect medical personnel against scattered rays, which are indirect X-rays, a lightweight material was prepared by mixing graphite oxide material, considering its thinness and flexibility. Tungsten particles were evenly dispersed in the polymer, and nanofibers were prepared using this blended polymer solution via electrospinning. Concurrently, the process technology was explored to craft a thin film sheet and obtain a lead-like shielding effect. A spinning solution was prepared by mixing Fe3O4-rGO (FerGO) and tungsten. At 60 kVp, 0.1 mm was measured as 0.097 mmPb, at 80 kVp, 0.2 mm was measured as 0.196 mmPb, and at 100 kVp, 0.3 mm was measured as 0.279 mmPb, showing similar shielding performance to lead. As density directly affects the shielding effect, graphene oxide played an important role in increasing the density of the material from 1.941 g/cm3 to 2.302 g/cm3. Thus, this study provides an effective process for producing thin film sheets equivalent to lead.

Development of ultra-thin radiation-shielding paper through nanofiber modeling of morpho butterfly wing structure.

In medical institutions, radiation shielding is an effective strategy to protect medical personnel and patients from exposure. Reducing the weight of the shield worn by medical personnel in the radiation generating area plays a key role in improving their productivity and mobility. In this study, a new lightweight radiation shield was developed by electrospinning a polymer-tungsten composite material to produce nanofibers with a multi-layered thin-film structure similar to that of a morpho butterfly wing. The fabricated shield was in the form of 0.1 mm thick flexible shielding paper. The multi-layer structure of the thin shielding paper was obtained through nanofiber pattern formation via electrospinning a dispersion of tungsten particles. At 0.1 mm thickness, the paper's shielding rate was 64.88% at 60 keV. Furthermore, at 0.3 mm thick and arranged in a laminated structure, the shielding rate was 90.10% and the lead equivalent was 0.296 mmPb. When used as an apron material, the weight can be reduced by 45% compared to existing lead products. In addition, the material is highly processable and can be used to manufacture various flexible products, such as hats, gloves, underwear, and scarves used in medical institutions.

A New Shielding Curtain for Protection of Intraoperative Radiation During Minimally Invasive Spine Surgery.

OBJECTIVE: Gradually increasing number of minimally invasive spine surgery (MISS), there is an increasing risk of radiation exposure to medical personnel during the surgery. We measured the radiation exposure of the operating room personnel during MISS, tried to find the riskiest person, and checked the effectiveness of a new lead-composite shielding curtain. METHODS: Radiation exposure of medical staffs (operator, first assistant, anesthesiologist, and scrub nurse) involved in MISS procedures of 35 patients without shielding curtain (nonshield group) and 35 patients with shielding curtain (shield group). The shielding curtain had 0.25-mm nominal lead equivalent and was mounted on 2 frame bars fixed on the operating table. RESULTS: In the nonshield group, radiation exposure was significantly higher in the order of operator > first assistant > scrub nurse > anesthesiologist (p < 0.001) during both anteroposterior (AP) and lateral views. In the shield group, the radiation exposure of the operator and the scrub nurse decreased significantly by 94.1% and 76.4% in AP view (p < 0.001), and by 96.3% and 73.9% in lateral view (p < 0.001), respectively. CONCLUSION: Since the radiation dose of the operator was highest in a C-arm-guided MISS, there is a high priority need to protect the operator from the radiation exposure. The shielding curtain could most effectively reduce the radiation exposure of the operator.

Multiparametric MR imaging of tumor response to intraarterial chemotherapy in orthotopic xenograft models of human metastatic brain tumor.

The purpose of our study was to investigate the therapeutic efficacy of intraarterial (IA) chemotherapy via multiparametric magnetic resonance imaging (MRI) analysis in orthotopic mouse brain tumor models. Stereotactic-guided intracranial inoculation of MDA-MB-231 cells was performed in nude mice. Thirty tumor bearing mice were randomized into three groups, and each group received either IA docetaxel administration (n = 10), intravenous (IV) docetaxel administration (n = 10), or IA solvent injection (n = 10) as control. Treatment response was monitored by diffusion-weighted imaging and dynamic contrast enhanced-MRI obtained 1 day before and 8 days after therapy initiation. Imaging results were correlated with histopathology. In the results, IA chemotherapy showed a significant decrease in tumor volume (86.5 ± 15.6 %) compared to the IV chemotherapy (121.1 ± 39.6%) and control (126.2 ± 22.0%) 8 days after therapy (p < 0.05). Furthermore, IA chemotherapy resulted in a significant increase in mean tumor apparent diffusion coefficient (ADC) values (116.8 ± 44.9%); in contrary IV chemotherapy (66.6 ± 26.9%) and control (69.1 ± 29.5%) showed a significant decrease in ADC values corresponding to further tumor growth (p < 0.05). However, there was no significant difference in perfusion parameters including initial area under the curve, K(trans), K(ep), and V(e) between the groups (p > 0.05). Histopathology confirmed necrosis and necroptosis in the tumors after IA chemotherapy. In conclusion, IA chemotherapy may lead to effective inhibition of tumor cell proliferation and offer potential benefit of inducing higher degree of treatment response than IV chemotherapy.

Endovascular treatment of unruptured ophthalmic artery aneurysms: clinical usefulness of the balloon occlusion test in predicting vision outcomes after coil embolization.

BACKGROUND: Endovascular coil embolization for ophthalmic artery (OphA) aneurysms has the latent risk of occlusion of the OphA during the procedure, which can lead to loss of vision. We report clinical and angiographic results of endovascular treatment of OphA aneurysms together with the efficacy of the balloon occlusion test (BOT). METHODS: From August 2005 to December 2013, 31 consecutive patients with 33 OphA aneurysms were treated in our institution. The patients were classified into two groups according to the location of the OphA within the aneurysmal sac. The BOT was performed in 28 patients using a hypercompliant balloon before endovascular coiling. Collateral circulation between the external carotid artery and the OphA was examined and visual function tests were performed before and after treatment. Patient demographics, angiographic and clinical outcomes were reviewed. RESULTS: Among the 28 patients who underwent the BOT, intact collateral circulation was demonstrated in 26 (92.9%) patients and complete occlusion of the OphA was obtained in three patients after coiling. Retrograde filling of the OphA with choroidoretinal blush was observed on post-procedural angiography and no specific visual symptoms were reported during the follow-up period. Complete embolization was achieved in 30 lesions (96.8%) and only five patients (16.1%) had minor recanalization. CONCLUSIONS: Endovascular treatment of OphA aneurysms can be performed safely and effectively in conjunction with BOT. The BOT may give useful information to predict visual outcome in patients whose OphA is likely to be threatened by the coiling procedure and to determine the optimal treatment strategy.

Long-term results of ethanol sclerotherapy with or without adjunctive surgery for head and neck arteriovenous malformations.

INTRODUCTION: Ethanol sclerotherapy has shown favorable short-term efficacy in managing head and neck arteriovenous malformation (AVM) which is well known for high recurrence rate after treatment. The purpose of this study was to report immediate treatment results and long-term follow-up results of ethanol sclerotherapy in patients with head and neck AVMs. METHODS: We performed a retrospective review of 45 patients with head and neck AVMs treated between April 1997 and December 2013 by using ethanol sclerotherapy with or without adjunctive surgery. The degree of AVM eradication was analyzed, and complications per treatment session were recorded. Long-term treatment effectiveness was assessed with clinical and imaging follow-up. RESULTS: In total, 132 sclerotherapies were performed in the 45 patients, with a total angiographic eradication rate of 17.8% (n = 8). Partial resolution was achieved in 34 patients, and three patients showed no response. Mean follow-up period was 56.6 months (range, 13-144 months). The long-term recurrence rate was 11.1% (5/45), and all recurrences occurred more than 3 years after the treatment with interval disease-controlled period. The major complication rate was 3.8% (5/132), and 34 minor complications (25.8%) occurred. CONCLUSIONS: Ethanol sclerotherapy is effective for achieving long-term durable cure of head and neck AVMs. In patients with non-curable disease, it is also effective for symptom palliation and long-term disease control. However, given recurrence after interval disease-controlled period, long-term follow-up should be required to detect recurrence in patients with any residual lesion after treatment.