作者: Toyonaga, Takuya ; Shiga, Tohru ; Kuge, Yuji ; Hirata, Kenji ; Nishijima, Ken-Ichi ; Okamoto, Shozo ; Tamaki, Nagara ; Magota, Keiichi ; Watanabe, Shiro

OBJECTIVEWe evaluated the radiation dosage, biodistribution, human safety, and tolerability of the injection of a single dose of [¹²³I] 5-iodo-6-[(2-iminoimidazolidinyl)methyl]uracil (IIMU), a new radiotracer targeting thymidine phosphorylase (TP), in healthy volunteers.METHODSPotential participants were tested at our hospital to confirm their eligibility. Two healthy male adults passed the screening tests. They were injected with 56 and 111 MBq of [¹²³I]IIMU, respectively. Safety assessments were performed before and at 1, 3, 6, 9, 24, 48 h, and 1-week post-injection. Whole-body emission scans were conducted at 1, 3, 6, 24, and 48 h post-injection. Regions of interest were manually drawn to enclose the entire body at each time point, identifying high-uptake organs to obtain the time-activity curves. Urine and blood samples were collected at 1, 2, 3, 4, 5, 6, 9, 24, and 48 h post-injection. The radiation dose for each organ and the effective doses were estimated using OLINDA/EXM 1.1 software.RESULTSNo adverse events were observed as of the follow-up visit > 1-week post-injection. In both subjects, the highest uptake of [¹²³I]IIMU occurred in the liver, with peak injected activity (%IA) values of 17.7% and 15.1%, respectively. The second highest uptake was in the thyroid (0.35% and 0.66% IA). The %IA decreased gradually toward the end of the study (48 h) in all organs except the liver and thyroid. By the end of the study, 52.5% and 51.5% of the injected activity of [¹²³I]IIMU had been excreted via the subjects' renal systems. The estimated mean effective doses of [¹²³I]IIMU were 9.19 μSv/MBq and 10.1 μSv/MBq, respectively.CONCLUSIONIn this preliminary study, [¹²³I]IIMU was safely administered to healthy adults, and its potential clinical use in TP imaging was revealed.

2019-01-01·Indian Journal of Nuclear Medicine

Comparison of image quality of different radionuclides technetium-99m, samarium-153, and iodine-123

Article

作者: Bonutti, Faustino ; Bouzekraoui, Youssef ; Bentayeb, Farida ; Asmi, Hicham

INTRODUCTIONThe choice of the radionuclide has a key role in nuclear medicine which appearing the lowest scatter fraction. In addition, the presence of penetrated and scattered photons from collimator in single-photon emission computed tomography images degrades resolution and contrast. Thus, image quality depends on sensitivity and resolution of the collimator-detector system. The goal of this study was to compare the image quality that can be achieved by three radionuclides: technetium-99 m (Tc-99 m), iodine-123 (I-123), and samarium-153 (Sm-153).MATERIALS AND METHODSTc-99 m and Sm-153 were imaged with low-energy high resolution (LEHR) collimator, while I-123 was imaged with medium-energy (ME) collimator. We modeled the Siemens Symbia Medical system using Monte Carlo simulation code SIMIND. The imaging characteristics of each radionuclide were investigated by simulated data: point spread function, sensitivity (Cps/MBq) and geometric, penetration and scattering distribution.RESULTSTc-99 m and Sm-153 give best and results with LEHR collimator for spatial resolution (full width at half maximum [FWHM] = 3.19 mm; full width at tenth maximum [FWTM] = 6.73 mm) and (FWHM = 3.22 mm; FWTM = 7.39 mm), respectively. Whereas, I-123 provided with ME collimator a lower resolution (FWHM = 4.89 mm; FWTM = 9.89 mm). The sensitivity recorded by Tc-99 m, Sm-153, and I-153 were (31.21 Cps/MBq), (10.16 Cps/MBq), and (51.22 Cps/MBq), respectively.CONCLUSIONTc-99 m and Sm-153 give the best and generally similar imaging properties with LEHR. For I-123, the ME collimator helps lowering the influence of high-energy gamma rays.

2017-01-07·Physics in Medicine and Biology2区 · 工程技术

Objective comparison of lesion detectability in low and medium-energy collimator iodine-123 mIBG images using a channelized Hotelling observer

2区 · 工程技术

Article

作者: Glenn Flux ; Jonathan Gear ; Sue Chua ; Wendy A Waddington ; Iain Murray ; Lucy Fowkes ; Rebecca A Gregory ; Daniel Levine ; Matthew D Aldridge

Iodine-123 mIBG imaging is widely regarded as a gold standard for diagnostic studies of neuroblastoma and adult neuroendocrine cancer although the optimal collimator for tumour imaging remains undetermined. Low-energy (LE) high-resolution (HR) collimators provide superior spatial resolution. However due to septal penetration of high-energy photons these provide poorer contrast than medium-energy (ME) general-purpose (GP) collimators. LEGP collimators improve count sensitivity. The aim of this study was to objectively compare the lesion detection efficiency of each collimator to determine the optimal collimator for diagnostic imaging. The septal penetration and sensitivity of each collimator was assessed. Planar images of the patient abdomen were simulated with static scans of a Liqui-Phil^™ anthropomorphic phantom with lesion-shaped inserts, acquired with LE and ME collimators on 3 different manufacturers' gamma camera systems (Skylight (Philips), Intevo (Siemens) and Discovery (GE)). Two-hundred normal and 200 single-lesion abnormal images were created for each collimator. A channelized Hotelling observer (CHO) was developed and validated to score the images for the likelihood of an abnormality. The areas under receiver-operator characteristic (ROC) curves, Az, created from the scores were used to quantify lesion detectability. The CHO ROC curves for the LEHR collimators were inferior to the GP curves for all cameras. The LEHR collimators resulted in statistically significantly smaller Azs (p < 0.05), of on average 0.891 ± 0.004, than for the MEGP collimators, 0.933 ± 0.004. In conclusion, the reduced background provided by MEGP collimators improved ¹²³I mIBG image lesion detectability over LEHR collimators that provided better spatial resolution.

100 项与 123I-IIMU 相关的药物交易

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