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1.
Opt Express ; 32(3): 3076-3084, 2024 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-38297538

RESUMEN

Compact electron sources have been instrumental in multidiscipline sciences including fundamental physics, oncology treatments, and advanced industries. Of particular interest is the terahertz-driven electron manipulation that holds great promise for an efficient high gradient of multi-GeV/m inside a regular dielectric-lined waveguide (DLW). The recent study relying on terahertz surface waves has demonstrated both high terahertz energy and improved coupling efficiency with the DLW. However, the large energy spread pertaining to the laser-induced electron pulse impedes the practical use of the system. Here, we propose a scheme for extending the idea of surface-wave-driven electron manipulation to mature electron sources such as commercial direct-current and radio-frequency electron guns. By using a simple hollow cylinder tube for electron transmission, we show that the electron energy modulation can reach up to 860 keV, or compress the electron pulse width to 15 fs using a 2.9 mJ single-cycle terahertz pulse. The trafficability of the hollow tube also allows for a cascade of the system, which is expected to pave the way for compact and highly efficient THz-driven electron sources.

2.
Opt Express ; 32(2): 2670-2678, 2024 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-38297790

RESUMEN

The interactions between high-intensity laser and matter produce particle flux and electromagnetic radiation over a wide energy range. The generation of extremely intense transient fields in the radio frequency-microwave regime has been observed in femtosecond-to-nanosecond laser pulses with 1011-1020-W/cm2 intensity on both conductive and dielectric targets. These fields typically cause saturation and damage to electronic equipment inside and near an experimental chamber; nevertheless, they can also be effectively used as diagnostic tools. Accordingly, the characterization of electromagnetic pulses (EMPs) is extremely important and currently a popular topic for present and future laser facilities intended for laser-matter interaction. The picosecond and sub-picosecond laser pulses are considerably shorter than the characteristic electron discharge time (∼0.1 ns) and can be efficient in generating GHz EMPs. The EMP characterization study of femtosecond laser-driven solid targets is currently mainly in the order of 100 mJ laser energy, in this study, the EMP generated by intense (Joule class) femtosecond laser irradiation of solid targets has been measured as a function of laser energy, laser pulse duration, focal spot size, and target materials. And a maximum electric field of the EMP reaching up to 105 V/m was measured. Analyses of experimental results confirm a direct correlation between measured EMP energy and laser parameters in the ultrashort pulse duration regime. The EMP signals generated by femtosecond laser irradiation of solid targets mainly originate from the return current inside the target after hot electron excitation. Numerical simulations of EMP are performed according to the target charging model, which agree well with the experimental results.

3.
Opt Lett ; 49(8): 1864-1867, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38621025

RESUMEN

The nonlinear mechanisms of polarization and optical fields can induce extensive responses in materials. In this study, we report on two kinds of nonlinear mechanisms in the topological semimetal PtSe2 crystal under the excitation of intense terahertz (THz) pulses, which are manipulated by the real and imaginary parts of the nonlinear susceptibility of PtSe2. Regarding the real part, the broken inversion symmetry of PtSe2 is achieved through a THz-electric-field polarization approach, which is characterized by second harmonic generation (SHG) measurements. The transient THz-laser-induced SHG signal occurs within 100 fs and recombines to the equilibrium state within 1 ps, along with a high signal-to-noise ratio (∼51 dB) and a high on/off ratio (∼102). Regarding the imaginary part, a nonlinear absorption change can be generated in the media. We reveal a THz-induced absorption enhancement in PtSe2 via nonlinear transmittance measurements, and the sheet conductivity can be modulated up to 42% by THz electric fields in our experiment. Therefore, the THz-induced ultrafast nonlinear photoresponse reveals the application potential of PtSe2 in photonic and optoelectronic devices in the THz technology.

4.
Small ; 19(4): e2204133, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36420659

RESUMEN

The acquired resistance to Osimertinib (AZD9291) greatly limits the clinical benefit of patients with non-small cell lung cancer (NSCLC), whereas AZD9291-resistant NSCLCs are prone to metastasis. It's challenging to overcome AZD9291 resistance and suppress metastasis of NSCLC simultaneously. Here, a nanocatalytic sensitizer (VF/S/A@CaP) is proposed to deliver Vitamin c (Vc)-Fe(II), si-OTUB2, ASO-MALAT1, resulting in efficient inhibition of tumor growth and metastasis of NSCLC by synergizing with AHP-DRI-12, an anti-hematogenous metastasis inhibitor by blocking the amyloid precursor protein (APP)/death receptor 6 (DR6) interaction designed by our lab. Fe2+ released from Vc-Fe(II) generates cytotoxic hydroxyl radicals (•OH) through Fenton reaction. Subsequently, glutathione peroxidase 4 (GPX4) is consumed to sensitize AZD9291-resistant NSCLCs with high mesenchymal state to ferroptosis due to the glutathione (GSH) depletion caused by Vc/dehydroascorbic acid (DHA) conversion. By screening NSCLC patients' samples, metastasis-related targets (OTUB2, LncRNA MALAT1) are confirmed. Accordingly, the dual-target knockdown plus AHP-DRI-12 significantly suppresses the metastasis of AZD9291-resistant NSCLC. Such modality leads to 91.39% tumor inhibition rate in patient-derived xenograft (PDX) models. Collectively, this study highlights the vulnerability to ferroptosis of AZD9291-resistant tumors and confirms the potential of this nanocatalytic-medicine-based modality to overcome critical AZD9291 resistance and inhibit metastasis of NSCLC simultaneously.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Ferroptosis , Neoplasias Pulmonares , ARN Largo no Codificante , Humanos , Carcinoma de Pulmón de Células no Pequeñas/genética , Neoplasias Pulmonares/genética , Receptores ErbB/metabolismo , Resistencia a Antineoplásicos/genética , Compuestos Ferrosos , Línea Celular Tumoral
5.
Opt Express ; 31(15): 23923-23930, 2023 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-37475232

RESUMEN

Matter manipulation in terahertz range calls for a strong-field broadband light source. Here, we present a scheme for intense terahertz generation from DSTMS crystal driven by a high power optical parametric chirped pulse amplifier. The generated terahertz energy is up to 175 µJ with a peak electric field of 17 MV/cm. The relationship between terahertz energy, conversion efficiency, and pump fluence is demonstrated. This study provides a powerful driving light source for strong-field terahertz pump-probe experimentation.

6.
Opt Lett ; 48(7): 1838-1841, 2023 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-37221779

RESUMEN

We demonstrate the stable and flexible light delivery of multi-microjoule, sub-200-fs pulses over a ∼10-m-long vacuumized anti-resonant hollow-core fiber (AR-HCF), which was successfully used for high-performance pulse synchronization. Compared with the pulse train launched into the AR-HCF, the transmitted pulse train out of the fiber exhibits excellent stabilities in pulse power and spectrum, with pointing stability largely improved. The walk-off between the fiber-delivery and the other free-space-propagation pulse trains, in an open loop, was measured to be <6 fs root mean square (rms) over 90 minutes, corresponding to a relative optical-path variation of <2 × 10-7. This walk-off can be further suppressed to ∼2 fs rms simply by using an active control loop, highlighting the great application potentials of this AR-HCF setup in large-scale laser and accelerator facilities.

7.
Mol Pharm ; 20(8): 4307-4318, 2023 08 07.
Artículo en Inglés | MEDLINE | ID: mdl-37486106

RESUMEN

Fibrosing mediastinitis (FM) is a rare proliferative disease within the mediastinum that leads to pulmonary hypertension, which has been regarded as a major cause of death. This study aims to evaluate the potential value of fibroblast activation protein inhibitor (FAPI)-PET/CT in the integration of diagnosis and treatment of FM through targeting FAPI in fibrosis rats and provide a theoretical basis for clinical management of FM patients. By performing a 18F-FAPI PET/CT scan, the presence of FAPI-avid in the fibrotic lesion was determined. Through a fibrosis rat model, 18F-FAPI-74 was used for lesion imaging and 177Lu-FAPI-46 was utilized to investigate the potential therapeutic effect on FM in vivo. In addition, biodistribution analysis and radiation dosimetry were carried out. With the 177Lu-FAPI-46 pharmacokinetic data of rats as the input, the estimated dose for female adults was computed, which can provide some useful information for the safe application of radiolabeled FAPI in the detection and treatment of FM in patients. Then, major findings on the use of FAPI PET/CT and SPECT/CT in FM were presented. 18F-FAPI-74 showed a high-level uptake in FM lesions of patients (SUVmax 7.94 ± 0.26), which was also observed in fibrosis rats (SUVmax 2.11 ± 0.23). Consistently, SPECT/CT imaging of fibrosis rats also revealed that 177Lu-FAPI-46-avid was active for up to 60 h in fibrotic lesions. In addition to this robust diagnostic performance, a possible therapeutic impact was evaluated as well. It turned out that no spontaneous healing of lesions was observed in the control group, whereas there was complete healing on day 9, day 11, and day 14 in the 30, 100, and 300 MBq groups, respectively. With a significant difference in the free of event rate in the Kaplan-Meier curve among four groups (P < 0.001), a dose of 300 MBq displayed the best therapeutic effect, and no obvious damage was observed in the kidney. Furthermore, organ-absorbed doses and an effective dose (0.4320 mSv/MBq) of 177Lu-FAPI-46 presumed for patients were assumed to give a preliminary indication of its safe use in clinical practice. In conclusion, 18F-FAPI-46 PET/CT can be a potentially valuable tool for the diagnosis of FM. Of note, 177Lu-FAPI-46 may be a novel and safe radiolabeled reagent for the integration of diagnosis and treatment of FM.


Asunto(s)
Mediastinitis , Quinolinas , Femenino , Animales , Ratas , Tomografía Computarizada por Tomografía de Emisión de Positrones , Distribución Tisular , Mediastinitis/diagnóstico por imagen , Mediastinitis/tratamiento farmacológico , Radioisótopos de Galio , Fluorodesoxiglucosa F18
8.
Sensors (Basel) ; 23(8)2023 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-37112162

RESUMEN

A low-profile, wideband, and high-gain antenna array, based on a novel double-H-shaped slot microstrip patch radiating element and robust against high temperature variations, is proposed in this work. The antenna element was designed to operate in the frequency range between 12 GHz and 18.25 GHz, with a 41.3% fractional bandwidth (FBW) and an obtained peak gain equal to 10.2 dBi. The planar array, characterized by a feed network with a flexible 1 to 16 power divider, comprised 4 × 4 antenna elements and generated a pattern with a peak gain of 19.1 dBi at 15.5 GHz. An antenna array prototype was fabricated, and the measurements showed good agreement with the numerical simulations as the manufactured antenna operated in the range of 11.4-17 GHz, with a 39.4% FBW, and the peak gain at 15.5 GHz was 18.7 dBi. The high-temperature simulated and experimental results, performed in a temperature chamber, demonstrated that the array performance was stable in a wide temperature range, from -50 °C to 150 °C.

9.
Minim Invasive Ther Allied Technol ; 32(3): 91-97, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36762759

RESUMEN

OBJECTIVE: To develop an alarm device for the mechanical compression device displacement (MCD), and further evaluate its effectiveness in clinical use. MATERIAL AND METHODS: The alarm device is mainly composed of buzzer, indicator light, magnetic sheet. This is a prospective randomized and controlled study. Four hundred patients who met the inclusion/exclusion criteria were included and randomly assigned to two groups (MCD group vs alarm + MCD group). The primary outcome measures were the sensitivity and specificity of the alarm device to detect MCD displacement, time to hemostasis (TTH), time to ambulation (TTA), time to hospital discharge (TTHD), hospital costs (HC), complication rates, and patient satisfaction. RESULTS: The sensitivity and specificity of the alarm device in detecting MCD displacement were 94.44% and 88.46%, respectively. The study group achieved shorter TTH (p = .034), shorter TTA (p = .021), lower complication rates (p = .025), and better patients' satisfaction (p < .001) compared to the control group. However, no significant difference was observed in TTHD (p = .361) and HC (p = .583). CONCLUSION: The alarm device is highly sensitive in detecting MCD displacement, while achieving better clinical outcomes compared with artificial monitoring.


Asunto(s)
Arteria Femoral , Técnicas Hemostáticas , Humanos , Arteria Femoral/cirugía , Estudios Prospectivos , Hemostasis , Punciones , Resultado del Tratamiento
10.
Opt Express ; 28(24): 35498-35505, 2020 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-33379663

RESUMEN

Coherent beam combination (CBC) is a promising technology for achieving several hundred petawatts and even EW-level lasers. However, the measurement of the synchronization error and the time jitter of CBC is one of key technical issues, especially in the few-cycle PW-level laser facilities. In this paper, we demonstrate that the absolute time delay (ATD) and the relative time delay (RTD) for a tiled-aperture CBC can simultaneously be measured by using the double-humped spectral beam interferometry. The experimental study also was demonstrated. A root-mean-square deviation of approximately λ/38 (70 as) and a combining efficiency of 87.3% at 1 Hz closed feedback loop was obtained, respectively. Due to the wide adjustment range and a vast resisting beam energy disturbance capacity, this technique provide an effective and practical solution for measuring simultaneously the ATD and the RTD in the few-cycle PW-level laser pulses CBC.

11.
Opt Express ; 28(10): 15258-15267, 2020 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-32403557

RESUMEN

The miscellaneous applications of terahertz have called for an urgent demand of a super intense terahertz source. Here, we demonstrate the capability of femtosecond laser-driven wires as an efficient ultra-intense terahertz source using 700 mJ laser pulses. When focused onto a wire target, coherent THz generation took place in the miniaturized gyrotron-like undulator where emitted electrons move in the radial electric field spontaneously created on wire surface. The single-cycle terahertz pulse generated from the target is measured to be radially polarized with a pulse energy of a few milijoule. By further applying this scheme to a wire-tip target, we show the near field of the 500 nm radius apex could reach up to 90 GV/m. This efficient THz energy generation and intense THz electric field mark a substantial improvement toward ultra-intense terahertz sources.

12.
Opt Express ; 26(3): 3684-3695, 2018 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-29401895

RESUMEN

Wavelength widely tunable femtosecond sources can be implemented by optically filtering the leftmost/rightmost spectral lobes of a broadened spectrum due to self-phase modulation (SPM) dominated fiber-optic nonlinearities. We numerically and experimentally investigate the feasibility of implementing such a tunable source inside optical fibers with negative group-velocity dispersion (GVD). We show that the spectral broadening prior to soliton fission is dominated by SPM and generates well-isolated spectral lobes; filtering the leftmost/rightmost spectral lobes results in energetic femtosecond pulses with the wavelength tuning range more than 400 nm. Employing an ultrafast Er-fiber laser and a dispersion-shifted fiber with negative GVD, we implement an energetic tunable source that produces ~100-fs pulses tunable between 1.3 µm and 1.7 µm with up to ~16-nJ pulse energy. Further energy scaling is achieved by increasing the input pulse energy to ~1-µJ and reducing the fiber length to 1.3 cm. The resulting source can produce >100-nJ femtosecond pulses at 1.3 µm and 1.7 µm with MW level peak power, representing an order of magnitude improvement of our previous results. Such a powerful source covers the 2nd and the 3rd biological transmission window and can facilitate multiphoton deep-tissue imaging.

14.
J Econ Entomol ; 108(3): 933-9, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26470213

RESUMEN

Pod borers are economically important soybean pests in temperate and tropical regions. However, the biological control of these pests using their natural insect enemies has been poorly studied to date. Indigenous natural populations of three Trichogramma (Hymenoptera: Trichogrammatidae) species, Trichogramma chilonis Ishii, Trichogramma ostriniae Pang & Chen, and Trichogramma leucaniae Pang & Chen, were collected from Leguminivora glycinivorella (Matsumura) (Lepidoptera: Tortricidae) eggs in soybean fields in China. In this study, we compare the parasitic capacities and suitabilities of three indigenous Trichogramma species on L. glycinivorella eggs at various ages. Host eggs of all ages were accepted by T. chilonis, T. ostriniae, and T. leucaniae. T. chilonis tended to parasitize 0-2-d-old eggs more than 3-4-d-old eggs. There were no significant differences in parasitism between the 0-2-d-old eggs and the 1-4-d-old eggs for T. ostriniae and T. leucaniae. For eggs at various ages, T. chilonis parasitized the smallest number of eggs, while T. leucaniae and T. ostriniae exhibited similar parasitic capacities. With 0-d-old host eggs, T. ostriniae developed over the longest time period (8.7 d), and T. leucaniae produced the most female progeny (87.9%). Both T. leucaniae and T. ostriniae had similar developmental times, survival rates and percentages of female progeny with 1-3-d-old eggs. These results show that T. leucaniae can parasitize host eggs at varying ages with the best development and suggest that it may be a valuable biological control agent for soybean pod borers.


Asunto(s)
Interacciones Huésped-Parásitos , Mariposas Nocturnas/parasitología , Avispas/fisiología , Animales , Agentes de Control Biológico , China , Mariposas Nocturnas/crecimiento & desarrollo , Mariposas Nocturnas/fisiología , Óvulo/parasitología , Óvulo/fisiología , Glycine max/crecimiento & desarrollo , Especificidad de la Especie
15.
MedComm (2020) ; 5(7): e613, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38898995

RESUMEN

The DNA-dependent protein kinase (DNA-PK), catalytic subunit, also known as DNA-PKcs, is complexed with the heterodimer Ku70/Ku80 to form DNA-PK holoenzyme, which is well recognized as initiator in the nonhomologous end joining (NHEJ) repair after double strand break (DSB). During NHEJ, DNA-PKcs is essential for both DNA end processing and end joining. Besides its classical function in DSB repair, DNA-PKcs also shows multifaceted functions in various biological activities such as class switch recombination (CSR) and variable (V) diversity (D) joining (J) recombination in B/T lymphocytes development, innate immunity through cGAS-STING pathway, transcription, alternative splicing, and so on, which are dependent on its function in NHEJ or not. Moreover, DNA-PKcs deficiency has been proven to be related with human diseases such as neurological pathogenesis, cancer, immunological disorder, and so on through different mechanisms. Therefore, it is imperative to summarize the latest findings about DNA-PKcs and diseases for better targeting DNA-PKcs, which have shown efficacy in cancer treatment in preclinical models. Here, we discuss the multifaceted roles of DNA-PKcs in human diseases, meanwhile, we discuss the progresses of DNA-PKcs inhibitors and their potential in clinical trials. The most updated review about DNA-PKcs will hopefully provide insights and ideas to understand DNA-PKcs associated diseases.

16.
J Thorac Dis ; 16(2): 1450-1462, 2024 Feb 29.
Artículo en Inglés | MEDLINE | ID: mdl-38505060

RESUMEN

Background: Bilateral synchronous multiple primary lung cancer (BSMPLC) presents significant clinical challenges due to its unique characteristics and prognosis. Understanding the risk factors that influence overall survival (OS) and recurrence-free survival (RFS) is crucial for optimizing therapeutic strategies for BSMPLC patients. Methods: We retrospectively analyzed clinical characteristics and treatment outcomes of 293 patients with BSMPLC who underwent surgical treatment between January 2010 and July 2017. Results: The 10-year OS and RFS rates were 96.1% and 92.8%, respectively. Preoperative forced expiratory volume in 1 second (FEV1) ≥70% [hazard ratio (HR), 0.214; 95% confidence interval (CI): 0.053 to 0.857], identical pathology types (HR, 9.726; 95% CI: 1.886 to 50.151), largest pT1 (HR, 7.123; 95% CI: 2.663 to 19.055), and absence of lymphovascular invasion (LVI; HR, 7.021; 95% CI: 1.448 to 34.032) emerged as independent predictors of improved OS. Moreover, the sum of tumor sizes less than or equal to 3 cm (HR, 6.229; 95% CI: 1.411 to 27.502) and absence of pleural invasion (HR, 3.442; 95% CI: 1.352 to 8.759) were identified as independent predictors of enhanced RFS. The presence or absence of residual nodules after bilateral surgery did not influence patients' OS (P=0.987) and RFS (P=0.054). Conclusions: Patients with BSMPLC who underwent surgery generally had a favorable prognosis. Whether or not to remove all nodules bilaterally does not affect the patient's long-term prognosis, suggesting the need for an individualized surgical approach.

17.
Opt Express ; 21(6): 7599-607, 2013 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-23546143

RESUMEN

We observe the high harmonic generation (HHG) from anti-aligned CO(2) molecules when the on-axis peak of HHG from HOMO-2 orbital disappears. The harmonic emission at anti-alignment can be attributed to the contribution of HOMO-1 orbital. Simulations reproduce these observations and reveal the angular distributions of tunneling ionization from HOMO and HOMO-1 respectively at different intensity. The determination of HOMO-1 orbital contributions in harmonic spectra is important for the tomography imaging of aligned molecules and analysis of the time evolved harmonic emission.


Asunto(s)
Dióxido de Carbono/química , Modelos Químicos , Análisis Espectral/métodos , Simulación por Computador
18.
Opt Express ; 21(20): 24120-8, 2013 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-24104322

RESUMEN

We report on the first direct observation of carrier-envelope-phase (CEP) effect during the interaction between few-cycle laser pulses and bulk solid materials. Using 2-cycle mid-infrared laser pulses with stabilized CEP, the CEP effect of tunneling ionization during the laser filamentation in a fused silica is revealed. The phase variation of the accompanying supercontinuum (SC) emission with filamentation at different CEPs of laser pulses can be measured by means of spectral interference technique, as a direct manifestation of the strong field tunneling ionization dynamics in transparent solids.

19.
Pest Manag Sci ; 79(4): 1500-1507, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36502497

RESUMEN

BACKGROUND: Chouioia cunea is a generalist pupal endoparasitoid. Native to Eurasia, the parasitoid has been mass-reared on an alternative lepidopteran host (Antheraea pernyi) to successfully control the exotic invasive lepidopteran pest Hyphantria cunea in China. To solicit more accessible hosts, this study evaluated the potential of an easily cultured coleopteran beetle (Tenebrio molitor) as a substitute for rearing C. cunea through comparing the relative performance of the parasitoids reared from both alternative hosts on H. cunea. RESULTS: Compared with those reared from A. pernyi, the parasitoids reared from T. molitor (i.e., T. molitor vs. A. pernyi groups) performed equally well in terms of parasitism rate (94.4 vs. 88.9%), number of offspring produced per parasitized host (278 vs. 286), and female body length (1.334 vs. 1.351 mm), hind-tibia length (0.322 vs. 0.324 mm) and number of mature oocytes in the ovarioles (171 vs. 187), or even better based on offspring pre-emergence time (16.0 vs 16.9 days) and percentages of emerged offspring (99.8 vs. 99.1%) and female offspring (97.1 vs. 91.3%). Flight performance testing indicated that young C. cunea adults emerged from T. molitor had a similar percentage of actively flying wasps (76.9 vs. 72.9%) and a lower percentage of inactive wasps (2.3 vs. 10.6%) when compared to those reared from A. pernyi. CONCLUSION: Given the remarkable adaptability of C. cunea and the vast availability of T. molitor as a common resource insect worldwide, this indigenous parasitoid could be mass-reared on T. molitor to improve the prospect of biological control of H. cunea in its invaded regions. © 2022 Society of Chemical Industry.


Asunto(s)
Escarabajos , Mariposas Nocturnas , Tenebrio , Avispas , Animales , Femenino , Pupa
20.
Quant Imaging Med Surg ; 13(6): 3760-3775, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-37284102

RESUMEN

Background: [18F] Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is an important tool for tumor assessment. Shortening scanning time and reducing the amount of radioactive tracer remain the most difficult challenges. Deep learning methods have provided powerful solutions, thus making it important to choose an appropriate neural network architecture. Methods: A total of 311 tumor patients who underwent 18F-FDG PET/CT were retrospectively collected. The PET collection time was 3 min/bed. The first 15 and 30 s of each bed collection time were selected to simulate low-dose collection, and the pre-90s was used as the clinical standard protocol. Low-dose PET was used as input, convolutional neural network (CNN, 3D Unet as representative) and generative adversarial network (GAN, P2P as representative) were used to predict the full-dose images. The image visual scores, noise levels and quantitative parameters of tumor tissue were compared. Results: There was high consistency in image quality scores among all groups [Kappa =0.719, 95% confidence interval (CI): 0.697-0.741, P<0.001]. There were 264 cases (3D Unet-15s), 311 cases (3D Unet-30s), 89 cases (P2P-15s) and 247 cases (P2P-30s) with image quality score ≥3, respectively. There was significant difference in the score composition among all groups (χ2=1,325.46, P<0.001). Both deep learning models reduced the standard deviation (SD) of background, and increased the signal-to-noise ratio (SNR). When 8%PET images were used as input, P2P and 3D Unet had similar enhancement effect on SNR of tumor lesions, but 3D Unet could significantly improve the contrast-noise ratio (CNR) (P<0.05). There was no significant difference in SUVmean of tumor lesions compared with s-PET group (P>0.05). When 17%PET image was used as input, SNR, CNR and SUVmax of tumor lesion of 3D Unet group had no statistical difference with those of s-PET group (P>0.05). Conclusions: Both GAN and CNN can suppress image noise to varying degrees and improve image quality. However, when 3D Unet reduces the noise of tumor lesions, it can improve the CNR of tumor lesions. Moreover, quantitative parameters of tumor tissue are similar to those under the standard acquisition protocol, which can meet the needs of clinical diagnosis.

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