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Objective:To investigate the advantage of three dimensional(3D)-printed tissue compensators in radiotherapy for superficial tumors at irregular sites.Methods:A subcutaneous xenograft model of prostate cancer in nude mice was established. Mice were randomly divided into no tissue compensator group( n=6), common tissue compensator group( n=6), and 3D-printed tissue compensator group( n=6). Computed tomography (CT) images of nude mice in the 3D-printed tissue compensator group were acquired. Compensator models were made using polylactic acid, and material properties were evaluated by measuring electron density. CT positioning images of the three groups after covering the corresponding tissue compensators were acquired to delineate the gross tumor volume (GTV). Nude mice in the three groups were irradiated with 6 MV X-rays at the prescribed dose. The prescribed dose for the three groups was 1 500 cGy. The dose distribution in the GTV of the three groups was calculated and compared using the analytical anisotropic algorithm in the Eclipse 13.5 treatment planning system. The metal-oxide-semiconductor field-effect transistor was used to verify the actual dose received on the skin surface of nude mice. Results:The air gap in the 3D-printed tissue compensator group and the common tissue compensator group was 0.20±0.07 and 0.37±0.07 cm 3, respectively ( t=4.02, P<0.01). For the no tissue compensator group, common tissue compensator group, and 3D-printed tissue compensator group, the D95% in the target volume was (1 188.58±92.21), (1 369.90±146.23), and (1 440.29±45.78) cGy, respectively ( F=9.49, P<0.01). D98% was (1 080.13±88.30), (1 302.76±158.43), and (1 360.23±48.71) cGy, respectively ( F=11.17, P<0.01). Dmean was (1 549.08±44.22), (1 593.05±65.40), and (1 638.87±40.83) cGy, respectively ( F=4.59, P<0.05). The measured superficial dose was (626.03±26.75), (1 259.83±71.94), and (1 435.30±67.22) cGy, respectively ( F=263.20, P<0.001). The percentage variation in tumor volume growth after radiation was not significantly different between the common tissue compensator group and the 3D-printed tissue compensator group ( P>0.05). Conclusions:3D-printed tissue compensators fit well to the body surface, which reduces air gaps, effectively increases the dose on the body surface near the target volume, and provides ideas for radiotherapy for superficial tumors at some irregular sites.
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@#<b>Objective</b> To study the feasibility of clinical application of an individualized customized material. <b>Methods</b> Five batches of individualized customized materials were randomly selected, from which 10 cm × 11 cm samples were intercepted for experimental analysis. Among them, 10 cm × 10 cm materials were selected to perform dosimetric analysis and HU change analysis before and after irradiation with a radiotherapy dose for breast cancer of 50 Gy as the irradiation basis. The center Point 1 on the lower surface of the individualized material and the center Point 2 of the solid water volume were selected for dosimetric analysis before and after the sample is irradiated. After reaching a sufficient amount of irradiation, the 1 cm × 10 cm materials intercepted in the center position and the remaining 1 cm × 10 cm materials after the first sampling were sent to the material science laboratory for analysis of physical properties of density, viscosity, hardness, and tear strength. <b>Results</b> In the comparative analysis of HU values before and after exposure, after receiving 50 Gy dose irradiation, the difference rate of HU value was 5.252%, which was close to the expected 5% difference rate in clinical medicine. In the dosimetric analysis of Point 1 and Point 2, the dose in the irradiated samples was significantly higher than that in the unirradiated samples; the dose in Point 1 increased by 3.742%, and the dose in Point 2 increased by 2.039%. Before and after irradiation, except for the physical density which showed a significant difference, there was no significant difference in viscosity, hardness, and tear strength. <b>Conclusion</b> The individualized customized material can meet the requirements of routine clinical medicine.
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Nanoparticles (NPs) have shown potential in cancer therapy, while a single administration conferring a satisfactory outcome is still unavailable. To address this issue, the dissolving microneedles (DMNs) were developed to locally deliver functionalized NPs with combined chemotherapy and photothermal therapy (PTT).
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BACKGROUND/AIMS: Endoscopic submucosal dissection (ESD) of a colorectal tumor is technically difficult. This study aimed to analyze the clinical outcomes of superficial large rectosigmoid tumors after ESD. METHODS: Medical records of 15 patients with large rectosigmoid tumors (more than 30 mm), in which ESD performed, were reviewed retrospectively. RESULTS: The mean tumor size was 42.5+/-14.3 mm (range, 30~78 mm). A histological examination revealed a well-differentiated adenocarcinoma in five cases (33.3%), adenoma with high-grade dysplasia in six cases (40%), and low-grade dysplasia in four cases (26.7%). The mean procedural time was 90.5+/-60.7 min (range, 22~246 min). The en bloc resection rate was 86.7%, and the complete resection rate 100%. The lateral resection margin was positive in four cases (26.6%), but no cases with a positive vertical margin were observed. Bleeding occurred in three cases (20%), and all were treated successfully using endoscopic measures. Perforations occurred in three cases (20%); two cases were treated by clipping and the other by a laparotomy. CONCLUSIONS: ESD is a treatment option for superficial large rectosigmoid tumors. Further studies with larger cases and a longer term follow-up are needed to establish the efficacy and safety of ESD for colorectal tumors.