Abstract: Provided is a T1 contrast agent for magnetic resonance imaging. The T1 contrast agent includes fine iron oxide nanoparticle cores and micelles encapsulating the core particles. The micelles include a nonionic surfactant consisting of a hydrophilic moiety containing at least two chains and a hydrophobic moiety containing at least one C10-C30 hydrocarbon chain. The T1 contrast agent of the present invention is a novel one based on fine iron oxide nanoparticles that can replace conventional gadolinium-based T1 contrast agents. The T1 contrast agent based on fine iron oxide nanoparticles according to the present invention is harmless to humans, is rapidly distributed in the blood, and has a uniform size, ensuring its uniform contrast effect. In addition, the T1 contrast agent of the present invention enables image observation for at least 1 hour to up to 2 hours and is excreted through the kidneys and liver.

Abstract: Disclosed herein are a time-based signal acquisition apparatus and method using sawtooth-shaped threshold voltage. The signal acquisition apparatus for acquiring the information of a scintillation signal includes a sawtooth-shaped voltage generation unit and a signal comparison unit. The sawtooth-shaped voltage generation unit generates a sawtooth-shaped threshold voltage which increases when the threshold voltage is smaller than a voltage value of the scintillation signal and which decreases to an initial value when the threshold voltage is larger than the voltage value of the scintillation signal. The signal comparison unit receives the scintillation signal, compares the voltage value of the scintillation signal with the threshold voltage, and generates a digital pulse train.

Abstract: Disclosed herein are a time-based signal acquisition apparatus and method using sawtooth-shaped threshold voltage. The signal acquisition apparatus for acquiring the information of a scintillation signal includes a sawtooth-shaped voltage generation unit and a signal comparison unit. The sawtooth-shaped voltage generation unit generates a sawtooth-shaped threshold voltage which increases when the threshold voltage is smaller than a voltage value of the scintillation signal and which decreases to an initial value when the threshold voltage is larger than the voltage value of the scintillation signal. The signal comparison unit receives the scintillation signal, compares the voltage value of the scintillation signal with the threshold voltage, and generates a digital pulse train.