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Metal-organic frameworks (MOFs) have shown a great potential as a novel contrast agent in magnetic resonance imaging (MRI) due to their unique properties including versatile structures, composition, and surface chemistry. Fe-MIL-88B-NH2 (MILs) was synthesized using Fe+3 ions and 2-aminoterephthalic acids (NH2-BDC) in the presence of acetic acid and Pluronic F127 under a hydrothermal process. Three MILs in different sizes were synthesized by using variant CH3COOH/Fe+3 molar ratios and denoted as MIL-S, MIL-M, and MIL-L having average sizes of 60, 350, and 730 nm, respectively. The effect of aspect ratio and particle size of MILs was investigated on proton relaxivity and contrast enhancement in aqueous, in vitro, and in vivo MR images. MRI study indicated that by increasing the MILs size, the incremental transverse relaxivity was achieved from 13.53 to 50.80 for r2 and from 38.75 to 60.25 for r2*, while the difference between r2 and r2* was decreased obviously. The r2/r1 ratios were found to be 5.80, 42.27, and 127.00 for MIL-S, MIL-M, and MIL-L, respectively. All MILs demonstrated T2-weighted MR imaging performance. Furthermore, no susceptibility artifacts were observed on T2-weighted images of MILs. By decreasing the size of MILs, r2/r1 ratio was reduced sharply and T1 contrast was also observed for MIL-S. MIL-S was used for in vitro and in vivo study due to its capability in simultaneous T1 and T2 contrast enhancements. MTT and hemolysis assays showed no significant cytotoxicity and hemolysis for MIL-S against normal human breast cell line (MCF-10A) and red blood cells, respectively, at concentrations of Fe+3 up to 300 μg/mL (p < 0.05). T1-weighted images acquired from in vitro study interestingly showed that the signal intensity of MIL-S is more than Dotarem. The in vivo experiment revealed that the signal intensity of mice liver decreased sharply after injection resulting in increase of negative contrast enhancement. The negative contrast enhancement decreased gradually by the time under T2-weighted imaging mode confirming application of MIL-S as a T2 contrast agent in biomedical applications (up to 12 h post-injection). Although a decrease of the size resulted in bright contrast in aqueous solution for MIL-S, it did not show proper efficiency for in vivo positive contrast enhancement. The advantages, including simple preparation and accessibility, acceptable potency and selectivity, blood compatibility, and suitable cytocompatibility as well as enough circulation time, make MIL-S as a dual MRI contrast agent to differentiate between low-contrast tissues for in vivo experiments. [ABSTRACT FROM AUTHOR]

Background: Nowadays, there has been a growing demand for low-dose computed tomography (LDCT) protocols. CT has a critical role in the management of the diagnosis chain of pulmonary disease, especially in lung cancer screening. There have been introduced several dose reduction methods, however, most of them are time-consuming, intricate, and vendor-based strategies that are hardly used in clinics routinely. This study aims to evaluate the image quality and pulmonary nodule detectability of LDCT protocols that are feasible and easy implemented. Image quality was analyzed in a general quality control phantom (Gammex) and then in a manmade lung phantom with nodules-equivalent objects., Methods: This study was designed in a two steps, in the first step, a feasible low-dose lung CT protocol was selected with quality assessment of accreditation phantom image. In the second step, the selected low-dose protocol with an appropriate image quality was performed on a manmade lung phantom in which there were objects equivalent to the pulmonary nodule. Finally, image quality parameters of the phantom at the appropriate scan protocol were compared with the standard protocol., Results: A reduction of about 17% of kVp and 46% in tube current leads to dose reduction by about 70%. The contrast-to-noise ratio in the low-dose protocol remained almost unchanged. The signal-to-noise ratio in the low-dose protocol decreased by approximately 32%, and the noise level has increased by about 1.5 times. However, this reduction method hardly affected the detectability of nodules in man-made pulmonary phantom., Conclusions: Here, we demonstrated that the LDCT scan has an insignificant effect on the perception of lung nodules. In this study, patient dose in lung CT was reduced by modifying of kVp and mAs about approximately 70%. Hence, to step in toward low-dose strategies in medical imaging clinics, using easy-implemented and feasible low-dose strategies may be helpful., Competing Interests: There are no conflicts of interest., (Copyright: © 2021 Journal of Medical Signals & Sensors.)

In Iran, a developing country in southwest Asia, an epidemiologic transition is underway from communicable to noncommunicable diseases. In Iran, cancer is the second largest group of chronic non-communicable diseases (NCDs) and the third most common cause of death following heart disease, accidents and other natural phenomena. There are some studies reporting an increasing trend in the incidence and mortality rate of a variety of cancers in Iran. Therefore, controlling and preventive interventions pertaining to cancers must be a main priority for health policy and it is recommended that the high-risk population receive earlier screening. In this review, incidence and mortality of colorectal, lung, liver, thyroid, and bladder cancers in Iran are reported., Competing Interests: The authors declare no conflict of interest.

Aim of the Study: Our objective was to quantify the accuracy of dose calculation in the build-up region of the tangential field of the breast for a TiGRT treatment planning system (TPS)., Material and Methods: Thermoluminescent dosimeter (TLD) chips were arranged in a RANDO phantom for the dose measurement. TiGRT TPS was also used for the dose calculation. Finally, confidence limit values were obtained to quantify the accuracy of the dose calculation of the TPS at the build-up region., Results: In the open field, for gantry angles of 15°, 30°, and 60°, the confidence limit values were 17.68, 19.97, and 34.62 at a depth of 5 mm, and 24.01, 19.07, and 15.74 at a depth of 15 mm, respectively. In the wedge field, for gantry angles of 15°, 30°, and 60°, the confidence limit values were 21.64, 26.80, and 34.87 at a depth of 5 mm, and 27.92, 22.04, and 20.03 at a depth of 15 mm, respectively. Additionally, the findings showed that at a depth of 5 mm, the confidence limit values increased with increasing gantry angle while at a depth of 15 mm, the confidence limit values decreased with increasing gantry angle., Conclusions: Overall, TiGRT TPS overestimated doses compared to TLD measurements, and the confidence limit values were greater for the wedge field than for the open fields. Our findings suggest that the assessment of dose distributions in large-dose gradient regions (i.e. build-up region) should not entirely rely on TPS calculations., Competing Interests: The authors declare no conflicts of interest. This work was financially supported by the office of vice president for research of Mashhad University of Medical Sciences.