Department of Medical Physics, Medicine Faculty, Mashhad University of Medical Sciences, Mashhad, Iran.
Finetech in Medicine Research Center, Iran University of Medical Sciences, Tehran, Iran.
Photochem Photobiol Sci. 2021 Feb;20(2):245-254. doi: 10.1007/s43630-021-00012-2. Epub 2021 Feb 9.
Photo-thermal therapy (PTT) has been at the center of attention as a new method for cancer treatment in recent years. It is important to predict the response to treatment in the PTT procedure. Using magnetic resonance spectroscopy (MRS) can be considered a novel technique in evaluating changes in metabolites resulted from PTT.
In the present project, we conducted an in vivo study to assess the efficacy of H-MRS as a noninvasive technique to evaluate the response to treatment in the early hours following PTT. The BALB/c mice subcutaneously bearing tumor cells (CT26 cell line) were scanned by H-MRS before and after PTT. Iron oxide-gold core-shell (FeO@Au) as PTT agent was injected into intra-peritoneal at first and then irradiated by NIR laser. Single-voxel Point RESolved Spectroscopy (PRESS) sequence (TE = 144) was used, and metabolites alternations were evaluated by the non-parametric Wilcoxon test. Besides, Nanoparticle (NP) relaxometry was conducted for negative contrast agents' potentials.
MRS choline (Cho) peak dramatically reduced 24 h post-PTT (p = 0.01) and lipid peak as a marker for necrosis of tumor elevated (p = 0.01) just in group 3 (NPs injection + laser irradiation) 24 h after the procedure.
H-MRS showed its potential as a method in detecting the changes in metabolites and revealing the outcome accurately. Response to photo-thermal therapy evaluation was achievable only one day after PTT and proved by a 10-day follow-up of the tumor size. Iron oxide-gold core-shell can also be used as a negative contrast agent in MRI images during therapy.
光热疗法（PTT）近年来作为癌症治疗的新方法备受关注。预测 PTT 过程中的治疗反应非常重要。使用磁共振波谱（MRS）可以被认为是评估 PTT 后代谢物变化的一种新方法。
在本项目中，我们进行了一项体内研究，以评估 H-MRS 作为一种非侵入性技术在 PTT 后早期评估治疗反应的效果。在 PTT 之前和之后，皮下携带肿瘤细胞（CT26 细胞系）的 BALB/c 小鼠通过 H-MRS 进行扫描。首先将氧化铁-金核壳（FeO@Au）作为 PTT 剂注入腹腔，然后用近红外激光照射。使用单体点分辨波谱（PRESS）序列（TE = 144），通过非参数 Wilcoxon 检验评估代谢物的变化。此外，还进行了纳米颗粒（NP）弛豫度测量，以评估负对比剂的潜力。
PTT 后 24 小时，MRS 胆碱（Cho）峰显著降低（p = 0.01），肿瘤坏死标志物脂质峰升高（p = 0.01），仅在第 3 组（NP 注射+激光照射）中观察到这种变化。
H-MRS 显示出作为一种检测代谢物变化并准确揭示结果的方法的潜力。仅在 PTT 后一天即可对光热治疗的反应进行评估，并通过对肿瘤大小的 10 天随访得到证实。氧化铁-金核壳也可在治疗期间用作 MRI 图像中的负对比剂。
