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Effect and mechanism of ZrO <sub/>2</sub> doping on the cracking behavior of melt‐grown Al <sub/>2</sub> O <sub/>3</sub> ceramics prepared by directed laser deposition
摘要： Photodynamic therapy (PDT), a treatment of choice for cancer, induces a photochemical reaction, thereby eradicating tumor cells. This is achieved through the administration of a photosensitizer drug, which is activated with a laser after localization to the tumor mass, and is an approved curative endoscopic ablative treatment for superficial esophageal squamous cell carcinoma (ESCC) in Japan. PDT has been approved for dysplastic Barrett’s esophagus and as a palliative treatment for patients with symptomatic obstructive esophageal cancer in US. However, its adverse events and complicated procedure and the development of alternative endoscopic procedures such as endoscopic submucosal dissection, radiofrequency ablation and cryotherapy, have largely limited the practice of PDT in esophageal cancer worldwide. Recently, owing to the invention of second-generation PDT using talaporfin sodium and diode laser, PDT can be performed with less phototoxicity and therefore has regained popularity in the treatment of ESCC. As a salvage treatment for patients with local failure after chemoradiotherapy (CRT), PDT has shown promising complete response with less phototoxicity and shorter sun shade period. In addition, the efficacy and safety of PDT in patients with local failure of ESCC after CRT were shown in several clinical trials. The direction of the study interest of the next-generation PDT is the safety and potential expansion of the indications for its application in the future. This review covers the PDT for the treatment of ESCC and dysplastic Barrett’s esophagus, with special focus on the role of PDT in practice for esophageal cancer.
关键词： photodynamic therapy,endoscopic submucosal dissection,esophageal cancer,squamous cell carcinomas,endoscopic treatment
更新于2025-09-11 14:15:04
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Comparison of treatment plans for a?high-field MRI-linac and a?conventional linac for esophageal cancer; Vergleich der Behandlungspl?ne von einem Hochfeld-MRT-Linac und einem konventionellen Linac beim ?sophaguskarzinom;
摘要： Purpose To compare radiotherapy treatments plans in esophageal cancer calculated for a high-?eld magnetic resonance imaging (MRI)-linac with plans for a conventional linac. Materials and methods Ten patients with esophageal squamous cell carcinomas were re-planned retrospectively using the research version of Monaco (V 5.19.03, Elekta AB, Stockholm, Sweden). Intensity modulated radiotherapy (IMRT) plans with a nine-?eld step-and-shoot technique and two-arc volumetric modulated arc therapy (VMAT) plans were created for the Elekta MRI-linac and a conventional linac, respectively. The prescribed dose was 60 Gy to the primary tumor (PTV60) and 50 Gy to elective volumes (PTV50). Plans were optimized for optimal coverage of the 60 Gy volume and compared using dose–volume histogram parameters. Results All calculated treatment plans met prede?ned criteria for target volume coverage and organs at risk dose both for MRI-linac and conventional linac. Plans for the MRI-linac had a lower number of segments and monitor units. No signi?cant differences between both plans were seen in terms of V20Gy of the lungs and V40Gy of the heart with slightly higher mean doses to the heart (14.0 Gy vs. 12.5 Gy) and lungs (12.8 Gy vs. 12.2 Gy). Conclusion Applying conventional target volume and margin concepts as well as dose-fractionation prescription re- veals clinically acceptable dose distributions using hybrid MRI-linac in its current con?guration compared to standard IMRT/VMAT. This represents an important prerequisite for future studies to investigate the clinical bene?t of MRI-guided radiotherapy exploiting the conceptional advantages such as reduced margins, plan adaptation and biological individual- ization and hypofractionation.
关键词： Intensity-modulated radiotherapy,Volumetric modulated arc therapy,Organs at risk,Squamous cell carcinomas,Magnetic resonance imaging
更新于2025-09-10 09:29:36