You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Influence of the bifunctional chelator on the pharmacokinetic properties of 99mTc(CO)3-labeled cyclic α-melanocyte stimulating hormone analog. Aiming at the design of specific melanocortin-1 receptor (MC1R) targeted imaging probes, we report on the effect of different azolyl-ring substitution patterns (carboxylate at the 4-position and/or methyl groups at the 3,5 positions) of pyrazolyl-diamine bifunctional chelators (Pz(2)-Pz(4)) on the pharmacokinetic profile of the (99m)Tc(CO)3-labeled lactam bridge-cyclized α-melanocyte stimulating hormone derivative, βAlaNleCycMSH(hex). Three pyrazolyl-diamine-containing chelators were conjugated to βAlaNleCycMSHhex, with the resulting peptide conjugates displaying subnanomolar MC1R binding affinity. Biodistribution studies in B16F1 melanoma-bearing mice show that all radiopeptides present a good melanoma uptake. The introduction of a carboxylate group in the azolyl-ring leads to a remarkable reduction of the kidney (>89%) and liver (>91%) accumulation for (99m)Tc(CO)3-Pz(3)-βAlaNleCycMSH(hex) and (99m)Tc(CO)3-Pz(4)-βAlaNleCycMSH(hex) when compared to the radiopeptide (99m)Tc(CO)3-Pz(1)-βAlaNleCycMSH(hex), where that group is absent. The good tumor uptake and favorable tumor-to-nontarget-organs ratios of (99m)Tc(CO)3-Pz(3)-βAlaNleCycMSH(hex) and (99m)Tc(CO)3-Pz(4)-βAlaNleCycMSH(hex) highlights the potential of both compounds as melanoma imaging agents.
{"Chemical": ["(99m)Tc(CO)3", "cyclized \u03b1-melanocyte stimulating hormone", "pyrazolyl-diamine", "\u03b2AlaNleCycMSH(hex)", "(99m)Tc(CO)3-Pz(4)-\u03b2AlaNleCycMSH(hex)", "(99m)Tc(CO)3-Pz(1)-\u03b2AlaNleCycMSH(hex)", "lactam", "azolyl", "cyclic \u03b1-melanocyte stimulating hormone", "\u03b2AlaNleCycMSHhex", "(99m)Tc(CO)3-Pz(3)-\u03b2AlaNleCycMSH(hex)", "carboxylate", "methyl", "99mTc(CO)3"]}