¹³¹I-ALG-ICG For Photothermal Therapy Of Anaplastic Thyroid Carcinoma

Objective:Thyroid carcinoma is the most common endocrine tumor.Generally,the most common treatment is surgical resection and adjuvant therapy with ¹³¹I.However,because of its rapid development and the molecular mechanism of ATC is still unclear,the diagnosis and treatment methods are limited,there is an urgent requirement for better diagnostic and treatment methods.In recent years,photothermal therapy（PTT）has been widely regarded as a minimally invasive treatment of carcinoma.PTT uses a material with photothermal effects to inject it into the human body so that it gathers near the tumor tissue,and converts light energy into heat energy under the irradiation of an external light source（usually near infrared light）to kill cancer cells.Its advantages are mainly to reduce the pain experienced by patients,short treatment time,obvious treatment effect,non-toxic and harmless materials,and very little side effects on the human body.Indocyanine green（ICG）is an FDA-approved water-soluble anionic cyanine dye.ICG can generate heat by near-infrared light irradiation,and because of its short half-life（3 minutes）,no light shielding is required after processing.In order to improve the stability of ICG,we can use sodium alginate（ALG）with gel-forming ability and combine ¹³¹I to further improve the therapeutic effect.Methods:Naturally occurring Ca²⁺/Mg²⁺in the human body can form a stable gel state of ALG.¹³¹I,ALG,and ICG can be mixed to obtain a ¹³¹I-ALG-ICG gel.The cytotoxic MTT test was used to determine whether ALG-ICG was toxic to cells.The stability was verified by beaker standing experiments.The prepared ¹³¹I-ALG-ICG gel was injected intratumorally,and its ability to aggregate ¹³¹I was observed by radionuclide imaging,as well as photothermal heating experiments,and cancer cell ablation at cellular level to verify its specific therapeutic effect.And through the staining of dead and living cells,it is more intuitive to prove that the treatment effect between the experimental group and the control group is significantly different.Results:We can observe that ¹³¹I-ALG-ICG still has high stability after 24 hours through beaker standing experiments.Through its photothermal curve and thermal ablation treatment of tumors,we can see that ICG has a good photothermal heating effect and is related to Compared with the control group,the gel has obvious therapeutic effect on tumors.The radionuclide imaging was divided into two groups.The free radioactive iodine 131 and ¹³¹I-ALG-ICG were injected respectively over the same time.The dispersion rate of the radionuclide in the gel system in the animals was significantly lower than that of the free radioactive iodine 131 group.According to the results of the cytotoxic MTT assay,it is known that ALG-ICG itself does not have cytotoxic effects.According to the cytotoxic MTT test results,it can be seen that ALG-ICG has no cytotoxic effect,and the staining of dead and living cells proves that the growth of tumors treated with ¹³¹I-ALG-ICG is significantly inhibited.Conclusions:In this experiment,we prepared the ¹³¹I-ALG-ICG with high stability and low toxicity by the simplest and fastest method for the combined radionuclide therapy and photothermo therapy for thyroid cancer.The prepared ¹³¹I-ALG-ICG not only has good photothermo therapy effect,radionuclide effect and excellent biocompatibility,but also has strong ICG fixation ability,which greatly improves the accumulation of photothermal agents in tumors.And minimize the potential side effects caused by ICG spread to surrounding tissues.This method provides a new research direction for ATC treatment that we have not yet solved.