In recent years tremendous effort has been invested in the field of cancer diagnosis and treatment with an overall goal of improving cancer management, therapeutic outcome, patient survival, and quality of life. Photodynamic Therapy (PDT), which works on the principle of light-induced activation of photosensitizers (PS) leading to Reactive Oxygen Species (ROS) mediated cancer cell killing has received increased attention as a promising alternative to overcome several limitations of conventional cancer therapies. Compared to conventional therapies, PDT offers the advantages of selectivity, minimal invasiveness, localized treatment, and spatio-temporal control which minimizes the overall therapeutic side effects and can be repeated as needed without interfering with other treatments and inducing treatment resistance. Overall PDT efficacy requires proper planning of various parameters like localization and concentration of PS at the tumor site, light dose, oxygen concentration and heterogeneity of the tumor microenvironment, which can be achieved with advanced imaging techniques. Consequently, there has been tremendous interest in the rationale design of PS formulations to exploit their theranostic potential to unleash the imperative contribution of medical imaging in the context of successful PDT outcomes. Further, recent advances in PS formulations as activatable phototheranostic agents have shown promising potential for finely controlled imaging-guided PDT due to their propensity to specifically turning on diagnostic signals simultaneously with photodynamic effects in response to the tumor-specific stimuli. In this review, we have summarized the recent progress in the development of PS-based multifunctional theranostic agents for biomedical applications in multimodal imaging combined with PDT. We also present the role of different imaging modalities; magnetic resonance, optical, nuclear, acoustic, and photoacoustic in improving the pre-and post-PDT effects. We anticipate that the information presented in this review will encourage future development and design of PSs for improved image-guided PDT for cancer treatment.

中文翻译：

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光敏剂作为成像引导癌症光动力治疗的多功能治疗诊断剂的最新进展。


近年来，人们在癌症诊断和治疗领域投入了巨大的努力，总体目标是改善癌症管理、治疗结果、患者生存和生活质量。光动力疗法 (PDT) 的工作原理是光诱导激活光敏剂 (PS)，从而导致活性氧 (ROS) 介导的癌细胞杀伤，作为克服传统癌症疗法的一些局限性的有希望的替代方案，受到越来越多的关注。与传统疗法相比，PDT具有选择性、微创、局部治疗、时空控制等优点，可以最大限度地减少整体治疗副作用，并且可以根据需要重复治疗，不会干扰其他治疗，不会产生治疗抵抗。总体 PDT 疗效需要适当规划各种参数，例如肿瘤部位 PS 的定位和浓度、光剂量、氧气浓度和肿瘤微环境的异质性，这可以通过先进的成像技术来实现。因此，人们对 PS 制剂的基本原理设计产生了极大的兴趣，以利用其治疗诊断潜力，在成功的 PDT 结果的背景下释放医学成像的重要贡献。此外，PS 制剂作为可激活光治疗剂的最新进展，由于它们倾向于在响应肿瘤特异性刺激的光动力效应的同时特异性地开启诊断信号，因此在精细控制的成像引导 PDT 方面显示出了巨大的潜力。 在这篇综述中，我们总结了基于 PS 的多功能治疗诊断剂在多模态成像联合 PDT 生物医学应用中的开发最新进展。我们还介绍了不同成像方式的作用；磁共振、光学、核、声学和光声可改善 PDT 前后的效果。我们预计本次综述中提供的信息将鼓励未来 PS 的开发和设计，以改进癌症治疗的图像引导 PDT。