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In clinical acupuncture, when acupuncture points are stimulated, several types of reflex responses can be evoked. Consequently, different categories of physiological responses are induced, which include changes in the activities of internal organs and tissues. The acupuncture point Sanyinjiao (SP6) has been used successfully to treat different human gastrointestinal conditions. The aim of this work was to investigate the effects of end-organ response induced by acupuncture point SP6 on the bioavailability of the radiopharmaceutical sodium pertechnetate (Na^99mTcO₄) in Wistar rats. Healthy rats were allocated into 2 groups, control-CG and treated-TG. TG was bilaterally stimulated at acupuncture point SP6 with stainless steel needles. Ocular plexus administration of Na^99mTcO₄ (3.7MBq) was carried out 10 min after every needle insertion in all animals. Ten minutes later, the animals were killed, the organs were isolated, the radioactivity was determined in a well gamma counter, and the percentage of injected dose per gram of tissue (%ID/g) was determined for each organ. The %ID/g was significantly altered (p < 0.05) in the small intestine of TG (0.56 ± 0.09) when compared to CG (0.82 ± 0.18). These results may suggest that this stimulation might induce physiological responses capable of altering the bioavailability of the radiopharmaceutical sodium pertechnetate. These findings aid in providing a better understanding of acupuncture and its effects on various organs and tissues.

Technetium and Rhenium are the two lower elements in the manganese triad. Whereas rhenium is known as an important part of high resistance alloys, technetium is mostly known as a cumbersome product of nuclear fission. It is less known that its metastable isotope ^99mTc is of utmost importance in nuclear medicine diagnosis. The technical application of elemental rhenium is currently complemented by investigations of its isotope ¹⁸⁸Re, which could play a central role in the future for internal, targeted radiotherapy. This article will briefly describe the basic principles behind diagnostic methods with radionuclides for molecular imaging, review the ^99mTc-based radiopharmaceuticals currently in clinical routine and focus on the chemical challenges and current developments towards improved, radiolabeled compounds for diagnosis and therapy in nuclear medicine.

Porphyrins are among the most important and widely used compounds involved in a variety of chemical and biochemical applications. These molecules exhibit very special properties that encourage researchers to label many derivatives with diagnostic or therapeutic radionuclides for medical applications. This study reports the radiolabeling and biodistribution of ${}^{99\mathrm{\text{m}}}$Tc-protoporphyrin IX (${}^{99\mathrm{\text{m}}}$Tc-PPIX) as a novel potential solid-tumor imaging agent. The factors affecting the radiolabeling process were varied to achieve maximum radiochemical yield. ${}^{99\mathrm{\text{m}}}$Tc-PPIX was obtained in high yield of 97.34 ± 0.21% and high stability in serum up to 24 h. The radiochemical yield of ${}^{99\mathrm{\text{m}}}$Tc-PPIX was assessed by a combination of a paper chromatographic technique and HPLC. A computational analysis for all the potential structures that may be formed due to the interaction between protoporphyrin IX and technetium was performed via the DFT method of calculations in gas phase to predict the most likely structure. Molecular docking was further employed to shed light on the nature of the interaction between the most stable complexes with the target protein. Finally, the in-vivo biodistribution of ${}^{99\mathrm{\text{m}}}$Tc-PPIX complex was evaluated in solid-tumor-bearing mice and high tumor/tissue ratio of 5.17 ± 0.34 at 60 min post injection was obtained. Our finding clearly suggests ${}^{99\mathrm{\text{m}}}$Tc-PPIX as a potential SPECT agent for tumor imaging.