In this research, novel AIE (Aggregation-Induced Emission) fluorophores were synthesized by ingeniously attaching a variety of substituents, including allyl, benzyl, and propargyl groups, to the hydroxy and carboxylate groups of fluorescein. The findings revealed a fascinating trend: the fluorescence intensity of these compounds varied progressively with the solvent ratio. This intriguing behavior is attributed to the superior aggregation of the synthesized materials in aqueous environments compared to organic solvents, resulting in markedly enhanced fluorescence. Moreover, the optical characteristics of these materials were found to be significantly influenced by the specific type of substituent grafted onto the fluorescein backbone. Notably, the fluorescence intensity was observed to escalate in the sequence of methoxy triethylene glycol, azidoethyl, allyl, propargyl, and benzyl group in the solution of H2O:DMSO (=99:1). The implications of this study can be vast, particularly in the realm of fundamental research areas like molecular imaging and sensor technology. These innovative AIE fluorophores offer a promising platform for advanced applications, leveraging their unique fluorescence behavior dictated by the nature of the substituent and the solvent environment.

In this study a liquid target design for producing radioisotopes at high-yield is proposed. The target was designed to operate under high power proton beam. During high power beam irradiation in liquid target the beam not only occurring a nuclear reaction but also combined with physical phenomena like phase change and internal flow causing by natural convection. The phase change could reduce production yield because the local density at the boiling bubble is lower. The possibility of nuclear reaction is higher in the liquid state than vapor state and the vapor should increase the pressure inside the target. Therefore the higher beam power causes higher internal pressure inside the target which could damage the target. The target was mechanically designed to overcome the high pressure with less boiling inside during high power beam irradiation. Also, additional design technique was introduced for easy to use and self-shielding body design for radiation protection. MC-50 cyclotron was used for the experiment. 3 cc of H₂¹⁸O water was filled in target and 20 MeV, 30 µA of proton beam was irradiated in target for one hour. The average production yield of F-18 was 2.6 Ci.

Generally, short half-life radioisotopes, such as ¹¹C and ¹⁸F are used in the development of radiopharmaceuticals for the diagnosis of brain disease. Several FDA-approved ¹¹C or ¹⁸F-labeled radiopharmaceuticals are applied clinically. However, radiometal-labeled radiopharmaceuticals have not received FDA approval with leaving a gap in the available options for healthcare professionals and patients. Radiometals are attractive radioisotopes, which can be synthesized in a simpler method than halides or carbon and have allowed the advances in both diagnosis and therapy. These advantages prompted the development of a new approach utilizing a hydrophobic porphyrin derivative that incorporated N,N-dimentyl-4-p-phyenylenediamine (DMPD) which has high affinity to tumor and redox active. In this study, we radiolabeled and evaluated porphyrin and 5,10,15,20-(tetra-N,N-diemethyl-4-aminophenyl)porphyrin (TDAP) which was composed of four DMPD conjugated to the porphyrin radiolabeled with radiometal, ⁶⁴Cu, to confirm their potential as brain tumor diagnostic agents. The radiochemical yield of [⁶⁴Cu]Cu-porphyrin was 57.2 ± 5.6% and that of [⁶⁴Cu]Cu-TDAP was 18.7 ± 2.0% and the radiochemical purity was over 95%. The stability of [⁶⁴Cu]Cu-porphyrin and [⁶⁴Cu]Cu-TDAP were confirmed over 95% for 24 hours in human and mouse serum. This protocol proposed the method of ⁶⁴Cu-labeling to hydrophobic porphyrin compounds.

Modelling the damage to DNA molecules by ionizing radiation plays a crucial part in predicting the biological effects of any form of radiation therapy, but the creation of accurate damage models remains scientifically challenging. This study evaluated the frequency and severity of DNA strand breaks caused by direct and indirect radiation effects using the Geant4 DNA simulation toolkit. The DNA itself was represented as a continuous fractal Hilbert curve with a total length of approximately 6.4 Gbp, consisting of straight and twisted chromatin sections placed inside a simplified model of a human fibroblast cell. Using At-211 and Ac-225, both alpha-emitting radionuclides employed under assumption of radiopharmaceutical treatment, the results were compared to those from external irradiation with 1.5 MeV gamma rays. For each Gy of absorbed dose, the strand break yields were 103 ± 10 SSBs/Gbp and 15 ± 4 DSBs/Gbp for At-211, 96 ± 10 SSBs/Gbp and 15 ± 4 DSBs/Gbp for Ac-225, as well as 198 ± 14 SSBs/Gbp and 7 ± 3 DSBs/Gbp for the gamma rays. Thus, the radionuclides exhibited more than double the incidence of DSBs at the expense of SSBs compared to the gamma radiation. By demonstrating the feasibility of adapting the Geant4 DNA toolkit for in silico studies of the radiobiological effects of therapeutic radiopharmaceuticals at the DNA level, this is the first step towards the development of a comprehensive simulation model for determining the relative biological effectiveness of radiopharmaceuticals.

Hydrogen sulfide (H₂S), recognized as the third gasotransmitter with specific implications for inflammation and hypoxia, exhibits affinity for ⁶⁴Cu immobilization. This study explores the viability of ⁶⁴Cu-labeled PET tracers in detecting endogenous H₂S. In vitro reactivity experiments involved evaluating the interaction between various concentrations of NaHS and ⁶⁴Cu-labeled chelators at 37℃ in a shaking incubator. In vivo molecular PET imaging studies were conducted using two distinct mouse models. An acute inflammation model, induced with carrageenan, involved administering 2.22 MBq/100 µL of [⁶⁴Cu]Cu-ATSM or [⁶⁴Cu]Cu-Cyclen intravenously 4 hours post-inflammation induction, with subsequent PET imaging in static 5 min mode. For the NaHS implantation model, NaHS dissolved in Matrigel was subcutaneously injected into the right dorsal region of BALB/c mice, followed by intravenous injection of radiotracers (2.22 MBq/100 µL) 1 hour later, and subsequent PET imaging. The optimized labeling condition involved dissolving 10 ㎍ of chelators in ammonium acetate buffer and reacting at 60℃ for 20 minutes. Both [⁶⁴Cu]Cu-Cyclen and [⁶⁴Cu]Cu-ATSM reacted with various concentrations of NaHS to form insoluble ⁶⁴CuS. High uptake of [⁶⁴Cu]Cu-ATSM and [⁶⁴Cu]Cu-Cyclen in acute inflammatory lesions in the mouse right footpad and the NaHS implantation model suggests their potential as imaging agents for inflammation and H₂S in vivo. In conclusion, optimized [⁶⁴Cu]Cu-ATSM and [⁶⁴Cu]Cu-Cyclen labeling conditions for endogenous H₂S imaging were established, confirming insoluble ⁶⁴CuS both in vitro and in vivo. [⁶⁴Cu]Cu-ATSM and [⁶⁴Cu]Cu-Cyclen hold promise as diagnostic agents targeting endogenous H₂S in various diseases associated with inflammation and hypoxia.

Medical devices are products that are directly related to the health of the public. The manufacture, distribution, sale, and aftercare of medical devices are regulated by law. Therefore, medical devices must be manufactured, distributed, sold, and maintained within the scope of the laws and regulations of the country in which they are intended to be used. The International Electrotechnical Commission (IEC) is an international standardization organization that develops standards for the safety of medical devices. The TC 62 subcommittee prepares international standards and other publications that focus on the safety and performance of medical equipment, software, and systems. Countries that dominate the medical device market, such as the United States and Europe, have adopted TC 62 subcommittee standards for medical devices and use them in their regulations. In Korea, the Medical Device Act proves the safety and effectiveness of medical devices and is based on the medical device standards developed by IEC TC 62. For this purpose, medical device developers need to understand regulatory requirements, have the ability to perform verification and certification procedures, and collaborate with regulatory experts to achieve regulatory approval quickly and efficiently. This study aims to identify the requirements for the industrialization of radiation-based medical devices and to identify the standards for regulated medical devices.

Malignant melanoma is a very aggressive metastatic skin cancer with a high mortality rate. Thus, an accurate early diagnosis of metastatic melanoma is the best treatment for patients. The melanocortin-1 receptor (MC1R) is overexpressed in human melanoma cells but exhibits low expression in normal tissues. This characteristic makes it an attractive target for detection of malignant melanoma. Alpha-melanocyte stimulating hormone (α-MSH), one of the endogenous ligands of MC1R, binds to MC1R through its core sequence. However, it is challenging to utilize the native structure of α-MSH, so researchers have found that stabilizing it through cyclization can offer more favorable outcomes in both preclinical and clinical studies. This review introduces the development of radionuclide-labeled α-MSH derivatives that selectively bind to MC1R, a malignant melanoma-specific target. It also explains on the development of cyclized α-MSH derivatives and the results of biological evaluations related to renal uptake.

Cu(II) diacetyl-di(N⁴-methylthiosemicarbazone), also known as Cu(II)-ATSM, is a popular copper-complexed thiosemicarbazone derivative that has been widely studied for hypoxia. [⁶⁴Cu]Cu-ATSM has emerged as an effective tracer for positron emission tomography imaging to functionally characterize hypoxic tumors. However, understanding the precise mechanism of cellular uptake and metabolism of Cu(II)-ATSM remains a controversial task in which different hypotheses have been proposed. Herein, we will elucidate the current findings regarding the hypoxic uptake mechanism of Cu(II)-ATSM. Particularly, we will investigate the cell internalization mechanism and intracellular reduction of Cu(II)-ATSM.