Radioactive Detection Research Articles

Pharmacokinetics, mass balance, and metabolism of [14C]TPN171, a novel PDE5 inhibitor, in humans for the treatment of pulmonary arterial hypertension.

TPN171 is a novel phosphodiesterase-5 (PDE5) inhibitor used to treat pulmonary arterial hypertension (PAH) and erectile dysfunction (ED), which currently is undergoing phase II clinical trials in China. In this single-center, single-dose, nonrandomized, and open design study, radiolabeled [14C]TPN171 was used to investigate the metabolic mechanism, pharmacokinetic characteristics, and clearance pathways of TPN171 in 6 healthy Chinese male volunteers. Each volunteer was administered a single oral suspension of 10 mg (100 μCi) of [14C]TPN171. We found that TPN171 was absorbed rapidly in humans with a peak time (Tmax) of 0.667 h and a half-life (t1/2) of approximately 9.89 h in plasma. Excretion of radiopharmaceutical-related components was collected 216 h after administration, accounting for 95.21% of the dose (46.61% in urine and 48.60% in feces). TPN171 underwent extensive metabolism in humans. Twenty-two metabolites were detected in human plasma, urine, and feces using a radioactive detector combined with a high-resolution mass spectrometer. According to radiochromatograms, a glucuronide metabolite of O-dealkylated TPN171 exceeded 10% of the total drug-related components in human plasma. However, according to the Food and Drug Administration (FDA) guidelines, no further tests are needed to evaluate the safety of this metabolite because it is a phase II metabolite, but the compound is still worthy of attention. The main metabolic biotransformation of TPN171 was mono-oxidation (hydroxylation and N-oxidation), dehydrogenation, N-dealkylation, O-dealkylation, amide hydrolysis, glucuronidation, and acetylation. Cytochrome P450 3A4 (CYP3A4) mainly catalyzed the formation of metabolites, and CYP2E1 and CYP2D6 were involved in the oxidative metabolism of TPN171 to a lesser extent. According to the incubation data, M1 was mainly metabolized to M1G by UDP-glucuronosyltransferase 1A9 (UGT1A9), followed by UGT1A7 and UGT1A10.

Study on the sequential Bayesian approach for a CsI(Tl)-based radioactive material detection system

Traditional algorithms based on energy spectra are widely used to detect radioactive materials in the field of nuclear security. However, it takes a long time to collect photons to obtain accurate energy spectra, which limits the warning time and increases false-alarm probability. The sequential Bayesian algorithm, which takes both photon energies and their interarrival time into account, could help improve the performance of radioactive detection. In this study, we propose a theoretical optimization method of the traditional sequential Bayesian algorithm to suit the parameters of the CsI(Tl) detector. Based on simulation data, dynamic environmental background parameters and repeated tests were added to the algorithm to further optimize its performance. Finally, with the improved sequential Bayesian algorithm, radioactive sources can be quickly detected by the CsI(Tl) detector with low false-alarm probability (less than 1.1 times per day).

Rapid detection method of radioactive source based on low-count gamma spectra

This paper presented a mobile CsI gamma detector developed to solve the problem of radioactive source detection in a wide area. The performance of the detector was illustrated during the spectra collection investigation. 1-s spectrum collected by the detector was low-count signal, which is hard to distinguish whether it is a source contained signal or not. A rapid detection method of radioactive source based on the low-count gamma spectra was proposed. Principal component analysis (PCA) was the key technology which was able to extract the source information efficiently. The proposed method improved the detector sensitivity and accuracy.

Research on the application of 22Na radiolocation detection technology in advanced manufacturing process control

Abstract This article mainly studies the positioning function of radioactive detection technology in process control for processing devices. The accuracy of 22Na detection is not limited by the spatial area by comparing different illumination scenarios; the accuracy of inspection is independent of the accuracy of machining equipment; the accuracy of the detection is not affected by the conditions of the processed body. This study is of great significance for the future radioactive detection technology to make up for the lack of precision caused by the existing sensor technology on the spatial positioning of the processing device, the illumination environment and the material characteristics of the processed body, and for the process control research in the field of advanced manufacturing.

An Improved Method for PWR Fuel Failure Detection Using Cascade-forward Neural Network With Decision Tree

When a fuel rod is damaged, determining the degree of fuel failure makes sense. The operators can decide whether to continue operating the reactor or shut it down based on the severity of the fuel failure. The isotopic ratio of two radioactive fission products (FPs) is a typical technique for evaluating the degree of fuel failure, although this is not applicable in the case of little fuel failure but large tramp uranium mass. The feedforward neural network (FFNN) has been used to identify fuel failures in order to overcome the shortcomings of the isotopic ratio method, although there is still inadequacy in the ability to distinguish between an intact fuel rod and a defective fuel rod with a small defect. In this study, we propose a cascade-forward neural network with a decision tree for fuel failure detection that performs well at classifying the degree of fuel failure and, in particular, at differentiating between an intact fuel rod and a defective fuel rod with a small size defect. The input of the neural network is the specific activity of FPs measured in the coolant. The degree of fuel failure is determined by the neural network’s output, which is labeled using one-hot encoding. The training set is constructed using the Booth-type diffusion model and the first-order kinetic model. The performance of the improved neural network is demonstrated. It is shown that the improved method is more accurate and responsive than the previous neural network when recognizing the onset of fuel failure. Finally, the most important nuclides are determined through the sensitivity analysis, and the neural network is simplified according to the importance of nuclides and the limitation of the radioactive detector in practical application.

Methods of Sentinel Lymph Node Detection and Management in Urinary Bladder Cancer-A Narrative Review.

Introduction: Detection of lymph node status in bladder cancer significantly impacts clinical decisions regarding its management. There is a wide range of detection modalities for this task, including lymphoscintigraphy, computed tomography, magnetic resonance imaging, single-photon emission computed tomography, positron emission tomography, and fluoroscopy. We aimed to study the pre- and intraoperative detection modalities of sentinel lymph nodes in urinary bladder cancer. Method: This narrative review was performed by searching the PubMed and EMBASE libraries using the following search terms: (“Transitional cell carcinoma of the bladder” OR “urothelial cancer” OR “urinary bladder cancer” OR “bladder cancer”) AND ((“sentinel lymph node”) OR (“lymphatic mapping”) OR (“lymphoscintigraphy”) OR (“lymphangiography”) OR (“lymph node metastases”)). Studies analysing the effectiveness and outcomes of sentinel lymph node detection in bladder cancer were included, while non-English language, duplicates, and non-article studies were excluded. After analysing the libraries and a further manual search of bibliographies, 31 studies were included in this paper. We followed the RAMESES publication standard for narrative reviews to produce this paper. Results: Of the 31 studies included, 7 studies included multiple detection methods; 5 studies included lymphoscintigraphy; 5 studies included computed tomography and/or single-photon emission computed tomography; 5 studies included fluoroscopy; 4 studies included magnetic resonance imaging; and 5 studies included positron emission tomography. Discussion: Anatomical, radioactive, and functional detection modalities have been studied independently and in combination. The consensus is that preoperative detection with imaging helps guide surgical management and intraoperative detection methods help capture any lymph nodes that may have been missed. Each of these types of detection represent their own set of benefits and drawbacks, but there is currently limited evidence to support any change in overall practice to replace conventional staging.

An IoT System for Radioactive Material Detection in Scrap Metal Recycling and Production Facilities

A radioactive source that is not under regulatory control because it is abandoned, lost, misplaced, stolen, or transferred without proper authorization is referred to as an orphan source. The melting of an orphan source, when mixed with scrap metal, has resulted in contaminated recycled metal and wastes and the consequences will be very serious for humans and the environment. In this paper, we propose and develop an Internet of Radiation Sensor System (IoRSS) to enhance the use of nuclear detection systems to detect nuclear and other radioactive materials out of regulatory control at points of entry/exit and other trade locations of scrap metal recycling and production facilities. The proposed IoRSS creates a robust and flexible network architecture along with advanced data fusion algorithms that combine information from many detectors. The test results show that the IoRSS system allows for accurate detection of radioactive sources and provides appropriate radiation incident response plans.

Axillary reverse mapping in breast cancer surgery - functional study.

The aim of the study was to map the lymphatic drainage of the upper extremity that traverses the axilla and elucidate its relationship with the lymphatic drainage of the breast. In 79 breast cancer patients indicated to the axillary lymph node dissection for category cN1, cN2, Technetium-99m (particle size <80 nm) was applied prior to surgery at two injection sites between the second and third metacarpophalangeal joints to visualize upper extremity lymphatics. During the surgery, the axilla was anatomically divided into 6 quadrants. A C-Trak® device was used for the intraoperative detection of radioactivity. After verifying activity, the nodes were resected and their position was recorded. Active nodes were sent separately according to topographic localizations for microscopic examination. All affected nodes (both macro- and micrometastases) were recorded as positive. The location, involvement and radioactivity, and the number of lymph nodes obtained were analyzed. In total, 1,109 lymph nodes were removed and examined. Radioactive nodes were found in all 79 patients. A total of 230 radioactive nodes were found. 21 nodes were both radioactive and metastatically affected. Results show that part of the lymph from the upper extremity flows through the nodes in the central part of the axilla and mixes with the lymph from the breast. This suggests that lymphatic drainage of the upper limb cannot be functionally separated from lymphatic drainage of the breast. The results also explain the possible mechanical cause of arm lymphedema after sentinel lymph node biopsy.

Radioactive mineralization detection using remote sensing and airborne gamma-ray spectrometry at Wadi Al-Miyah area, Central Eastern Desert, Egypt

Band rationing, principal component analysis (PCA) and decorrelation stretch (DS) techniques of Landsat-8 with Sentinel-2 data successfully used in the discrimination of the lithological units and the surface structure features of Wadi Al-Miyah area in the Central Eastern Desert of Egypt. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) were processed to identify the hydrothermal mineralized alteration zones related to the radioactive minerals. Airborne gamma-ray spectrometry (AGRS) has been used to determine the naturally occurring radioactive anomalous zones such as potassium (K), equivalent uranium (eU) and equivalent thorium (eTh) and to follow their spatial distribution in Wadi Al-Miyah area. The analysis of AGRS data revealed that, the study area owns a wide range of radioelement concentrations ranging from 15.5 to 98.4 μR/h, 5.9–37.1 ppm, 17.2–95.4 ppm, and 0.53%-10.29% of total count (TC), (eU), (eTh), and (K), respectively. The interpretation of the Radioelements Composite Image (RCI) successfully delineated the enrichment zones with radioelement concentrations within the alkali feldspar granite, biotite-muscovite schist, granodiorite and the hydrothermal alteration areas within the diorite of Gabal Al- Bakriyah. The results concluded that the integrated remote sensing and airborne AGRS data are promising in detecting the potential areas enriched with K, eU and eTh.

The Notre-Dame Cube: An active-target time-projection chamber for radioactive beam experiments and detector development

Active-target detectors have the potential to address the difficulties associated with the low intensities of radioactive beams. We have developed an active-target detector, the Notre Dame Cube (ND-Cube), to perform experiments with radioactive beams produced at TwinSol and to aid in the development of active-target techniques. Various aspects of the ND-Cube and its design were characterized. The ND-Cube was commissioned with a 7Li beam for measuring 40Ar + 7Li fusion reaction cross sections and investigating 7Li(α, α)7Li scattering events. The ND-Cube will be used to study a range of reactions using light radioactive ions produced at low energy.

Advances in the analytical methods for the determination of fluorinated aromatic carboxylic acids in aqueous matrices: A review.

Fluorobenzoic acids are critically important chemical tracers in hydrothermal, geothermal, leaching, and oilfield applications. Particularly in oilfield applications, these tracers are used to investigate fluid flow paths between injector wells and producer wells, providing valuable information about the enhanced oil recovery process of the oil reservoirs. The detection limit of tracers is a vital subject in field reservoir work because the amount of chemical tracer that must be injected into the injector well is directly related to the amount detected at the producer well after migration and diffusion. The popularity of fluorinated benzoic acids as the tracers is due to their non-toxicity over radioactive tracers and low detection limit, which is determined using analytical techniques. This review focuses on the improvements/developments in extraction techniques such as solid-phase extraction and determination techniques such as gas chromatography coupled with mass spectrometry, liquid chromatography with mass spectrometry, isotope dilution gas chromatography-mass spectrometry, high-performance liquid chromatography, ion chromatography coupled with electrospray mass spectrometry, and so on for the analysis of fluorinated benzoic acids to achieve the lowest possible limit of concentration.

Screener3D: a gaseous time projection chamber for ultra-low radioactive material screening

In experiments searching for rare signals, background events from the detector itself are some of the major factors limiting search sensitivity.Screening for ultra-low radioactive detector materials is becoming ever more essential. We propose to develop a gaseous time projection chamber (TPC) with a Micromegas readout for radio screening. The TPC records three-dimensional trajectories of charged particles emitted from a flat sample placed in the active volume of the detector. The detector can distinguish the origin of an event and identify the particle types with information from trajectories, which significantly increases the screening sensitivity. For $\alpha$ particles from the sample surface, we observe that our proposed detector can reach a sensitivity higher than 100 $\mu$Bq$\cdot$m$^{-2}$ within two days.

Imaging of Glioblastoma Tumor-Associated Myeloid Cells Using Nanobodies Targeting Signal Regulatory Protein Alpha

Glioblastoma (GBM) is the most common malignant primary brain tumor. Glioblastomas contain a large non-cancerous stromal compartment including various populations of tumor-associated macrophages and other myeloid cells, of which the presence was documented to correlate with malignancy and reduced survival. Via single-cell RNA sequencing of human GBM samples, only very low expression of PD-1, PD-L1 or PD-L2 could be detected, whereas the tumor micro-environment featured a marked expression of signal regulatory protein alpha (SIRPα), an inhibitory receptor present on myeloid cells, as well as its widely distributed counter-receptor CD47. CITE-Seq revealed that both SIRPα RNA and protein are prominently expressed on various populations of myeloid cells in GBM tumors, including both microglia- and monocyte-derived tumor-associated macrophages (TAMs). Similar findings were obtained in the mouse orthotopic GL261 GBM model, indicating that SIRPα is a potential target on GBM TAMs in mouse and human. A set of nanobodies, single-domain antibody fragments derived from camelid heavy chain-only antibodies, was generated against recombinant SIRPα and characterized in terms of affinity for the recombinant antigen and binding specificity on cells. Three selected nanobodies binding to mouse SIRPα were radiolabeled with 99mTc, injected in GL261 tumor-bearing mice and their biodistribution was evaluated using SPECT/CT imaging and radioactivity detection in dissected organs. Among these, Nb15 showed clear accumulation in peripheral organs such as spleen and liver, as well as a clear tumor uptake in comparison to a control non-targeting nanobody. A bivalent construct of Nb15 exhibited an increased accumulation in highly vascularized organs that express the target, such as spleen and liver, as compared to the monovalent format. However, penetration into the GL261 brain tumor fell back to levels detected with a non-targeting control nanobody. These results highlight the tumor penetration advantages of the small monovalent nanobody format and provide a qualitative proof-of-concept for using SIRPα-targeting nanobodies to noninvasively image myeloid cells in intracranial GBM tumors with high signal-to-noise ratios, even without blood-brain barrier permeabilization.

Comparative In vitro Metabolism of Enflicoxib in Dogs, Rats, and Humans: Main Metabolites and Proposed Metabolic Pathways.

BackgroundEnflicoxib is a non-steroidal anti-inflammatory drug of the coxib family characterized by a long-lasting pharmacological activity that has been attributed to its active metabolite E-6132.ObjectivesThe aim of this work was to explore enflicoxib biotransformation in vitro in humans, rats and dogs, and to determine its metabolic pathways.MethodsDifferent in vitro test systems were used, including hepatocytes and liver and non-hepatic microsomes. The samples were incubated with enflicoxib and/or any of its metabolites at 37°C for different times depending on the test system. The analyses were performed by liquid chromatography coupled with either radioactivity detection or high-resolution mass spectrometry.ResultsEnflicoxib was efficiently metabolized by cytochrome P-450 into three main phase I metabolites: M8, E-6132, and M7. The non-active hydroxy-pyrazoline metabolite M8 accounted for most of the fraction metabolized in all the three species. The active pyrazol metabolite E-6132 showed a slow formation rate, especially in dogs, whereas metabolite M7 was a secondary metabolite formed by oxidation of M8. In hepatocytes, diverse phase II metabolite conjugates were formed, including enflicoxib glucuronide, M8 glucuronide, E-6132 glucuronide, M7 glucuronide, and M7 sulfate. Metabolite E-6132 was most probably eliminated by a unique glucuronidation reaction at a very low rate.ConclusionThe phase I metabolism of enflicoxib was qualitatively very similar among rats, humans and dogs. The low formation and glucuronidation rates of the active enflicoxib metabolite E-6132 in dogs are postulated as key factors underlying the mechanism of its long-lasting pharmacokinetics and enflicoxib's overall sustained efficacy.

Enhancing the sensitivity for weak radioactive source detection

Considering the difficulties of the low signal-to-noise ratio in weak radioactive source detections, this study proposes an abandon Gaussian tails method based on the analysis of the characteristic information denoted by the full-energy peak of the gamma spectrum of a gamma-emitting radioactive source. Based on the study of the signal-to-background ratio and the statistical fluctuations in the signal of the weak radioactive source, a factor ζ, incorporating the statistical fluctuations of signal and background and the signal-to-background ratio, is suggested to characterize the sensitivity of a radioactive source detection. When ζ reaches its maximum value, the optimal counting window around the centroid of the full-energy peak can be obtained. To evaluate the effectiveness of the proposed approach, comparisons between the proposed abandon Gaussian tails, the conventional full-energy counting, and other experiential methods were performed. The results show that the sensitivity can be significantly improved. Further, experiments with different intensity of radiation sources and duplicated experiments were conducted to examine the stability of the proposed method.

Whole-Body Radioiodine Effective Half-Life in Patients with Differentiated Thyroid Cancer.

Background: Radioactive 131I (RAI) therapy is used in patients with differentiated thyroid cancer (DTC) after total thyroidectomy for remnant ablation, adjuvant treatment or treatment of persistent disease. 131I retention data, which are used to indicate the time at which a 131I treated DTC patient can be released from the hospital, may bring some insights regarding clinical factors that prolong the length of hospitalization. The aim of this study was to investigate the 131I whole-body retention in DTC patients during 131I therapy. Methods: We monitored 166 DTC patients to follow the 131I whole-body retention during 131I therapy with a radioactivity detector fixed on the ceiling of each protected room. A linear regression fit permitted us to estimate the whole-body 131I effective half-life in each patient, and a relationship was sought between patients’ clinical characteristics and whole-body effective 131I half-life. Results: The effective 131I half-life ranged from 4.08 to 56.4 h. At multivariable analysis, longer effective 131I half-life was related to older age and extensive extra-thyroid disease. Conclusions: 131I effective half-life during 131I treatment in DTC patients is highly variable among patients and is significantly longer in older and in patients with RAI uptake in large thyroid remnants or in extrathyroidal disease that significantly prolongs the whole-body retention of 131I.

Detection of radioactivity for some materials that used in construction and for some area that was exposed to the weapons of depleted uranium and estimating its health risks

This study aims to evaluate occupational radiation doses inside and outside the houses that have used remnants of depleted uranium weapons (RDUW) to establish the roofs of their house and estimating their risks to the population health. Survey radiation dosimeter used to estimate average radiation doses inside and outside the houses with RDUW (25houses) and without RDUW (25 houses). Health risks are evaluated through analysis of complete blood tests and concentration of Potassium ion K＋, Sodium ions Na＋ with pH test for the 50 male donor blood samples. The maximum average radiation dose was 1.093 ± 0.07 Sv/hr measured inside the exposed houses of Shwan location/ Kirkuk governorate, and this makes the health risk more significant in that location. Elevated levels of radiation affected the results of the CBC tests and K＋, Na＋concentration with pH levels in the blood samples. The concentration of potassium ions (K＋) and pH increases with a high radiation dose. In contrast to that, the concentration of sodium ions (Na＋) declines with increasing radiation dose.

Radiation effects on residents caused by comprehensive utilization of slag in building materials

Objective This study intends to analyze the radioactivity level of slag and its building materials, estimate the effective dose of the residents caused by the comprehensive utilization of slag in building materials, and provide basis for rational utilization of slag. Methods Data of slag production and its comprehensive utilization in building materials, radioactive level investigation and detection of slag and building materials in different periods and regions were collected from 2005 to 2016. Using the room model of concrete structure and the model of calculating equilibrium equivalent radon concentration with the specific activity of 226Ra in indoor building materials, the external and internal radiation doses of residents caused by comprehensive utilization of slag for building materials were estimated respectively, and then the annual additional effective dose and collective dose of residents were estimated. Results The contents of 226Ra and 232Th in the slag were relatively high, while the contents of 40K were relatively low. The radionuclide content in slag cement decreased significantly. The annual additional effective doses of slag used in concrete and cement mixture relative to ordinary cement were 40 mSv · a –1 and 0.20 mSv · a –1 respectively. The annual additional collective dose and 50-year collective dose caused by slag used in building materials were 3.87 × 10 3~1.84 × 10 4 man · Sv and 1.94 × 10 5~9.20 × 10 5 man · Sv respectively. Conclusion The comprehensive utilization of slag in building materials increases the additional effective dose of residents, so the use of some slag in building materials needs to be paid more attention to. In addition, the influence of comprehensive utilization of slag in building materials, such as the way, the amount of slag and the amount of building materials, on the annual additional effective dose of residents caused should also be paid attention to. 摘要： 目的 本研宄拟分析矿渣及其建材的放射性水平, 估算矿渣综合利用于建材所致居民的有效剂量, 为合理利用 矿渣提供依据。 方法 收集 2005—2016 年矿渣产生量和综合利用于建材量的资料, 以及不同时期、不同地区的矿渣 及其建材放射性水平调查与检测的资料等。采用混凝土结构房间模型、室内建材中 226Ra 比活度推算平衡当量氡浓度 的模式分别估算矿渣综合利用于建材所致居民的外照射和内照射剂量, 进而估算居民年附加有效剂量和集体剂量。 结果 矿渣中 226Ra 和 232Th 的含量相对较高, 40K 含量较低, 矿渣水泥中的放射性核素含量较矿渣中明显降低; 矿渣用 于混凝土和水泥混合材料相对普通水泥住房导致公众附加年有效剂量分别为0.40 mSv · a –1 和 0.20 mSv · a –1, 矿渣用 于建材所致公众年附加集体剂量和 50 年集体剂量分别为 3.87 × 10 3~1.84 × 10 4 人· Sv 和 1.94 × 10 5~9.20 × 10 5 人· Sv。 结论 矿渣综合利用于建材使居民附加有效剂量有所增加, 利用某些矿渣生产建材需要引起一定的重 视;此外, 矿渣综合利用于建材的方式、利用量、建材使用量等对其所致居民年附加有效剂量的影响也需关注。

Novel double injection technique for sentinel lymph node biopsy in oral cancer

The development of new lymphatic tracers and the advancement of hybrid tracers, such as indocyanine green (ICG)-Nanocoll (GE Healthcare), represent an exciting step in the future of sentinel lymph node biopsy (SLNB). These tracers aim to improve our ability to detect sentinel lymph nodes by enhancing their localisation. The aim of this study was to assess the performance of a novel dual tracer, double injection technique of ICG-‘cold’-Nanocoll and radiolabelled Nanocoll, in SLNB for early-stage oral cancer. A double injection technique was performed first using 99mTc-Nancoll prior to sentinel node imaging followed by ICG-‘cold’-Nanocoll injection in theatre. Analysis involved examination of the number, labelling, and location of the nodes harvested, sentinel node status, survival analysis, false negative rate, and complications associated with use of the technique. ICG ‘cold’ Nanocoll results showed concordance of fluorescence and radioactivity detection in 74 nodes in 24 patients. Most importantly, all nodes found positive for metastasis (6 nodes) were discovered to be both ‘hot’ and fluorescent; 74 nodes removed were both ‘hot’ and fluorescent, eight fluorescent only and six ‘hot’ only. Our results indicate that two sets of tracer injections given at two different time points will flow to the same sentinel nodes. This double labelling increased our confidence that the retrieved node was a sentinel node.

Genetically encoded FRET fluorescent sensor designed for detecting MOF histone acetyltransferase activity in vitro and in living cells

Acetylation of lysine in the histone H4 N-terminal is one of the most significant epigenetic modifications in cells. Aberrant changes involving lysine acetylation modification are commonly reported in multiple types of cancers. Currently, whether it is for in vivo or in vitro, there are limited approaches for the detection of H4 lysine acetylation levels. In particular, the main problems are the high cost and the cumbersome detection process, such as for radioactive 14C isotope detection. Therefore, there is an important need to develop a simple, fast, and low-cost means of detection. In this study, we reported the development of a gene-coding protein sensor. This protein sensor was designed based on the mechanism of fluorescence resonance energy transfer (FRET). The four kinds of sensors, varying from substrate and linker length, were evaluated, with ~20% increases in response efficiency. Next, sensors with different lysine mutation sites in the substrate sequence or mutation of key amino acids in the binding domain were also analyzed to determine site specificity. We found single-site lysine mutant could not cause a significant decrease in response efficiency. Furthermore, addition of MG149, a histone acetyltransferase inhibitor, resulted in a decrease in the ratio change value. Moreover, histone deacetylase1 HDAC1 was also found to reduce the ratio change values when added to reaction system. Finally, the optimized sensor was applied to living cells and established to provide a sensitive response with overexpression and knockdown of MOF (males absent on the first). These results indicated that the sensor can be used for screening chemical drugs regulating H4 N-terminal lysine acetylation level in vitro, as well as monitoring dynamic changes of lysine acetylation levels in living cells.