[en] Objective: The aim of this study was to investigate the value of ¹⁸F-fiuoroerythronitromidazole (FETNIM) in detecting tumor hypoxia in vivo. Methods: BALB/c nude mice were xenografted with SPCA-1 lung cancer cells. Tumors were allowed to grow to a diameter about 10 mm. In group A (n= 16), ¹⁸F-FETNIM (37 MBq) was injected from tail vein. Biodistribution of ¹⁸F-FETNIM was studied at 0.5, 1, 2, and 3 h after tracer injection. Blood, muscle, heart, liver, kidney, fat, lung, and tumor were moved and weighted. The radioactivity was measured with percentage activity of injection dose per gram of tissue (% ID/g) by a γ-counting well. In group B (n=14), the intratumoral PO₂ measurements were obtained by polar graphic oxygen needle probe. Results: The radioactivity was highest in kidney and lowest in fat and bone matrix. The maximum tumor to blood (T/B) and tumor to muscle(T/M) ratios were 1.69 ± 0.37 and 1.57 ± 0.47 at 2 h after injection. Intratumoral PO₂ measurements were ranged from 1.1 to 27.7 mm Hg (1 mm Hg=0.133 kPa) and were 30.2 to 40.5 mm Hg for normal tissue. Conclusion: A relatively high ¹⁸F-FETNIM retention ratio indicated ¹⁸F-FETNIM to be a potential agent for detecting tumor hypoxia in vivo. (authors)

[en] Objective: To investigate the radiosensitization of silencing HIF-lα by RNA interference in human lung adenocarcinoma cells (SPCA-l). Methods: HIF-lα RNA interference (RNAi)vector (pSUPER-HIF-1α) was constructed by using pSUPER plasmid. The RNAi effect was detected by RT-PCR and Western blot in SPCA-1 cell line, both under normoxia and hypoxia condition. The radiosensitization effect of silencing HIF-α was measured by colony forming assay. Results: after silencing the HIF-lα by RNAi, the expression of HIF-lα mRNA was decreased to 64% and 76% under normoxia and hypoxia condition, respectively; the expression of HIF-1α protein was inhibited under hypoxia condition. The Do of cells transfected with pSUPER-HIF-lα, pSUPER and controlled cell was 2.5, 5.0 and 5.1 Gy, respectively, with a radiosensitization ratio of 2.1. Conclusion: RNA-in-terference targeting silenced HIF-lα may increase the radiosensitivity of SPCA-1 cell line. (authors)

[en] Highlights: • We employed a modal representation method to construct twisted Laguerre-Gaussian Schell-model beams. The twist factor of the beam model not only exists in the twist phase but also in correlation function, which shows that such beam model is quite different from conventional twisted partially coherent beams. • We can adjust the beam profile of twisted Laguerre-Gaussian Schell-model beams not only in the source plane but also in the far field. • Adjusting both the mode order and twist factor of the proposed beams to enhance the total OAM of the beams and improve their resistance to turbulence, which will be helpful in free-space communication. In this paper, we introduce a new class of twisted partially coherent beams with a prescribed correlation function, twisted Laguerre-Gaussian Schell-model (TLGSM) beams, whose twist factor not only exists in the twist phase but also in correlation function. Analytical expressions for the cross-spectral density function propagating in free space and in turbulence are derived based on the extended Huygens-Fresnel integral. The evolution of the spectral intensity and orbital angular momentum (OAM) are discussed. Our results show that adjusting both the mode order and twist factor of the proposed beams to enhance the total OAM of the beams and, simultaneously, improve their resistance to turbulence. With multiple degrees of freedom that can be adjusted to optimize the beam for different turbulence conditions, TLGSM beams are an excellent candidate for use in optical applications in challenging media.