Successful Adjuvant Intraoperative Electron Beam Radiotherapy for Keloid: First Case Report and Review of Literature

Treatment of keloids is usually challenging, requiring a multimodal approach with no universally accepted treatment modality among the wide range of alternative keloid treatments. Excision of keloid lesion usually eliminates symptoms and it is the main treatment with considerable recurrence rate. Recurrence rate ranges from 45-100% when surgical excision is performed as monotherapy. Furthermore, Recurrent Keloids have a higher recurrence rate after surgery. In this case we discuss a challenging case of young female presented with third recurrence in lobule of the ear with defect necessitated flap reconstruction with concern for possible damage by the flap if radiation was given as external beam postoperatively. Intraoperative electron beam therapy was utilized with high safety and efficacy. To our knowledge this is the first case in the Middle East to use this technique in treating Keloid. Conclusion Treatment of keloids is usually challenging, requiring a multimodal approach. Excision of keloid lesion usually eliminates symptoms and it is the main treatment with considerable recurrence rate .Recurrence rate ranges from 45-100% when surgical excision is performed as monotherapy. Furthermore, Recurrent Keloids have a higher recurrence rate after surgery. Radiation is a valid option for decreasing risk of recurrence in recurrent keloid with high safety and efficacy profile. In this case we discuss a challenging case of young female presented with third recurrence in lobule of the ear with defect necessitated flap reconstruction with concern for possible damage by the flap if radiation was given as external beam postoperatively. Intraoperative electron beam therapy was utilized with high safety and efficacy. To our knowledge this is the first case in the Middle East to use this technique in treating Keloid. Keywords: Keloid; Radiation; Intraoperative Radiation; IOeRT

The pH Value Control of Morphology and Luminescence Properties of Gd2O2S: Tb3+ Phosphors

Developing rare-earth doped oxysulfide phosphors with diverse morphologies has significant value in many research fields such as in displays, medical diagnosis, and information storage. All of the time, phosphors with spherical morphology have been developed in most of the related literatures. Herein, by simply adjusting the pH values of the reaction solution, Gd2O2S:Tb3+ phosphors with various morphologies (sphere-like, sheet-like, cuboid-like, flat square-like, rod-like) were synthesized. The XRD patterns showed that phosphors with all morphologies are pure hexagonal phase of Gd2O2S. The atomic resolution structural analysis by transmission electron microscopy revealed the crystal growth model of the phosphors with different morphology. With the morphological change, the band gap energy of Gd2O2S:Tb3+ crystal changed from 3.76 eV to 4.28 eV, followed by different luminescence performance. The samples with sphere-like and cuboid-like microstructures exhibit stronger cathodoluminescence intensity than commercial product by comparison. Moreover, luminescence of Gd2O2S:Tb3+ phosphors have different emission performance excited by UV light radiation and an electron beam, which when excited by UV light is biased towards yellow, and while excited by an electron beam is biased towards cyan. This finding provides a simple but effective method to achieve rare-earth doped oxysulfide phosphors with diversified and tunable luminescence properties through morphology control.

Communication—Electron-Beam Stimulated Release of Dislocations from Pinning Sites in GaN

To achieve low leakage in GaN-based power devices and improve reliability in optoelectronic devices such as laser diodes, it is necessary to reduce dislocation density in epitaxial layers and control their introduction during processing. We have previously shown that dislocations can be introduced at room temperature in GaN. The effect of electron-beam irradiation at fixed points on the shift of such freshly introduced dislocations in GaN is reported. Dislocations can be displaced up to 10-15 µm from the beam position. We conclude the main reason limiting the dislocation travelling distance is the existence of a high number of pinning sites.