Automatic planning for functional lung avoidance radiotherapy based on function-guided beam angle selection and plan optimization.

Objective.This study aims to develop a fully automatic planning framework for functional lung avoidance radiotherapy (AP-FLART).Approach.The AP-FLART integrates a dosimetric score-based beam angle selection method and a meta-optimization-based plan optimization method, both of which incorporate lung function information to guide dose redirection from high functional lung (HFL) to low functional lung (LFL). It is applicable to both contour-based FLART (cFLART) and voxel-based FLART (vFLART) optimization options. A cohort of 18 lung cancer patient cases underwent planning-CT and SPECT perfusion scans were collected. AP-FLART was applied to generate conventional RT (ConvRT), cFLART, and vFLART plans for all cases. We compared automatic against manual ConvRT plans as well as automatic ConvRT against FLART plans, to evaluate the effectiveness of AP-FLART. Ablation studies were performed to evaluate the contribution of function-guided beam angle selection and plan optimization to dose redirection.Main results.Automatic ConvRT plans generated by AP-FLART exhibited similar quality compared to manual counterparts. Furthermore, compared to automatic ConvRT plans, HFL mean dose,V20, andV5were significantly reduced by 1.13 Gy (p< .001), 2.01% (p< .001), and 6.66% (p< .001) respectively for cFLART plans. Besides, vFLART plans showed a decrease in lung functionally weighted mean dose by 0.64 Gy (p< .01),fV20by 0.90% (p= 0.099), andfV5by 5.07% (p< .01) respectively. Though inferior conformity was observed, all dose constraints were well satisfied. The ablation study results indicated that both function-guided beam angle selection and plan optimization significantly contributed to dose redirection.Significance.AP-FLART can effectively redirect doses from HFL to LFL without severely degrading conventional dose metrics, producing high-quality FLART plans. It has the potential to advance the research and clinical application of FLART by providing labor-free, consistent, and high-quality plans.

Evaluating Virtual Contrast-Enhanced Magnetic Resonance Imaging in Nasopharyngeal Carcinoma Radiation Therapy: A Retrospective Analysis for Primary Gross Tumor Delineation.

PURPOSE: To investigate the potential of virtual contrast-enhanced magnetic resonance imaging (VCE-MRI) for gross-tumor-volume (GTV) delineation of nasopharyngeal carcinoma (NPC) using multi-institutional data. METHODS AND MATERIALS: This study retrospectively retrieved T1-weighted (T1w), T2-weighted (T2w) MRI, gadolinium-based contrast-enhanced MRI (CE-MRI), and planning computed tomography (CT) of 348 biopsy-proven NPC patients from 3 oncology centers. A multimodality-guided synergistic neural network (MMgSN-Net) was trained using 288 patients to leverage complementary features in T1w and T2w MRI for VCE-MRI synthesis, which was independently evaluated using 60 patients. Three board-certified radiation oncologists and 2 medical physicists participated in clinical evaluations in 3 aspects: image quality assessment of the synthetic VCE-MRI, VCE-MRI in assisting target volume delineation, and effectiveness of VCE-MRI-based contours in treatment planning. The image quality assessment includes distinguishability between VCE-MRI and CE-MRI, clarity of tumor-to-normal tissue interface, and veracity of contrast enhancement in tumor invasion risk areas. Primary tumor delineation and treatment planning were manually performed by radiation oncologists and medical physicists, respectively. RESULTS: The mean accuracy to distinguish VCE-MRI from CE-MRI was 31.67%; no significant difference was observed in the clarity of tumor-to-normal tissue interface between VCE-MRI and CE-MRI; for the veracity of contrast enhancement in tumor invasion risk areas, an accuracy of 85.8% was obtained. The image quality assessment results suggest that the image quality of VCE-MRI is highly similar to real CE-MRI. The mean dosimetric difference of planning target volumes was less than 1 Gy. CONCLUSIONS: The VCE-MRI is highly promising to replace the use of gadolinium-based CE-MRI in tumor delineation of NPC patients.

Pancreatic Perivascular Epithelioid Cell Tumor Revealed by 68 Ga-DOTATATE PET/CT.

ABSTRACT: We report 68 Ga-DOTATATE PET/CT findings of pancreatic perivascular epithelioid cell tumor in a 55-year-old woman. 68 Ga-DOTATATE PET/CT showed increased radioactivity in the region of pancreatic body, which suggested malignant tumor. However, postoperative pathological findings demonstrated the presence of perivascular epithelioid cell tumor. This case emphasizes the need to increase awareness of this tumor in the differential diagnosis of pancreatic nodules with moderate DOTATATE activity.

Preparation of TiO2 and Fe-TiO2 with an Impinging Stream-Rotating Packed Bed by the Precipitation Method for the Photodegradation of Gaseous Toluene.

Nano-TiO2 has always been one of the most important topics in the research of photocatalysts due to its special activity and stability. However, it has always been difficult to obtain nano-TiO2 with high dispersion, a small particle size and high photocatalytic activity. In this paper, nano-TiO2 powder was prepared by combining the high-gravity technique and direct precipitation method in an impinging stream-rotating packed bed (IS-RPB) reactor followed by Fe3+ in-situ doping. TiOSO4 and NH3·H2O solutions were cut into very small liquid microelements by high-speed rotating packing, and the mass transfer and microscopic mixing of the nucleation and growth processes of nano-TiO2 were strengthened in IS-RPB, which was beneficial to the continuous production of high quality nano-TiO2. Pure TiO2 and iron-doped nano-TiO2 (Fe-TiO2) were obtained in IS-RPB and were investigated by means of X-ray diffraction (XRD), Raman, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) and Brunauer-Emmett-Teller (BET) analysis, which found that pure TiO2 had a particle size of about 12.5 nm, good dispersibility and a complete anatase crystal at the rotating speed of packing of 800 rpm and calcination temperature of 500 °C. The addition of Fe3+ did not change the crystalline structure of TiO2. Iron was highly dispersed in TiO2 without the detection of aggregates and was found to exist in a positive trivalent form by XPS. With the increase of iron doping, the photoresponse range of TiO2 to visible light was broadened from 3.06 eV to 2.26 eV. The degradation efficiency of gaseous toluene by Fe-TiO2 under ultraviolet light was higher than that of pure TiO2 and commercial P25 due to Fe3+ effectively suppressing the recombination of TiO2 electrons and holes; the highest efficiency produced by 1.0% Fe-TiO2 was 95.7%.

Piwil2-transfected human fibroblasts are cancer stem cell-like and genetically unstable.

Uncontrolled cell proliferation and inhibition of apoptosis are considered to be vital for cancer initiation, maintenance, infiltration, metastasis and recurrence after anti-cancer therapy. Here we report the generation of a novel cell line by reprogramming child foreskin fibroblast with the full length apoptosis inhibitor gene PIWIL2. The fibroblasts transfected with PIWIL2 expressed the stem cell markers OCT-4, NANOG, SOX-2, KLF-4 and C-MYC; endoderm marker AFP and GATA6; mesoderm markers ACTA2 and BRACHYURY; and ectoderm markers NESTIN and TUBB3. The karyotype was found to be hyperdiploid. The PIWIL2 transfected fibroblast cells grew into tumorous masses within 5 weeks of subcutaneous injection into adult nude mice. Although the injected cell expressed markers for all three germlines, ectoderm, mesoderm, and endoderm, they did not form teratomas in vivo. This study indicates that the PIWIL2 gene could play a key role in cancer induction and maintenance. This method for generating induced tumorigenic cells (ITGC) provides a new research tool to study oncogenesis that in turn may lead to a better understanding of cancer etiology and the development of novel anti-cancer therapies.

Co-expression of Piwil2/Piwil4 in nucleus indicates poor prognosis of hepatocellular carcinoma.

PURPOSE: This study aimed to explore the localization and expression of P-element-induced wimpy testis-like 2 (piwil2)/Piwil4 in hepatocellular carcinoma (HCC) tissues, and analyze the correlation between co-expression pattern and prognosis of HCC. RESULTS: Piwil2 showed 100% positive expression in the cell nucleus, with the intensity higher than in the cytoplasm. Piwil4 showed a lower intensity of expression in the cell nucleus than in the cytoplasm. The molecular chaperone Piwil2/Piwil4 had four co-expression patterns: nuclear co-expression, nuclear and cytoplasmic co-expression, cytoplasmic co-expression, and non-coexpression. The survival rate and the overall survival sequentially increased. The prognostic phenotype of the nuclear co-expression of Piwil2/Piwil4 was worse than that of non-coexpression, and the intracellular localization and expression of Piwil2 and Piwil4 were not significantly different. METHODS: HCC pathological tissue samples with follow-up information (90 cases) and 2 normal control liver tissues were collected and made into a 92-site microarray. The expression of Piwil2 and Piwil4 was detected using the immunofluorescence double staining method. The differences in the expression and location of Piwil2 and Piwil4 in tumor cells were explored, and the influence of such differences on the long-term survival rate of HCC was studied using Kaplan-Meier survival curve and log-rank test. The clinical staging was analyzed according to the HCC international TNM staging criteria. CONCLUSIONS: The nuclear co-expression of Piwil2/Piwil4 indicated that patients with HCC had a worse prognostic phenotype. The molecular chaperone Piwil2/Piwil4 seems promising as a molecular marker for prognosis judgment; a single marker (Piwil2/Piwil4) cannot be used for prognosis judgment.

[Histological features of tumor-bearing tissues formed by human fibroblasts after reprograming by Piwil2].

OBJECTIVE: To observe the histological features of tumor-bearing tissues formed by human fibroblasts after reprograming by spermatogonial stem cell self-renewal key regulating gene Piwil2 (Piwil2-iCSC). METHODS: Piwil2-iCSC tumor spheroids-like colonies were selected for tumor formation assay in four nude mice. Pathological features of Piwil2-iCSC tumors were observed by histology. Stem cell markers and common triploblastic markers were detected by reverse transcriptase-polymerase chain reaction (RT-PCR) assay and immunohistochemistry. Germ cell tumor markers were detected by immunohistochemical examination. RESULTS: Two weeks after inoculation, subcutaneous tumors were formed in all the four nude mice with a tumor formation rate of 100%. In the Piwil2-iCSC tumor tissues, Piwil2-GFP(+) cells showed high-density nuclear expression and were widely observed in DAPI-stained sections. Numerous mitotic figure of the neoplastic cells were seen (>10 cells/field of vision under high magnification) in HE-stained sections. Enlarged abnormal cell nuclei were observed. RT-PCR assay showed that Piwil2-iCSC tumors still expressed Piwil2 and some self-renewal and pluripotent markers of stem cells and some markers of triploblastic differentiation. Immunohistochemical staining showed that the tumors expressed stem cell markers, triploblastic markers and germ cell tumor markers AFP and HCG. CONCLUSIONS: Piwil2-iCSC tumors are probably undifferentiated embryonic small cell carcinoma, most likely to be immature teratoma, mixed with yolk sac tumor and choriocarcinoma components. It can be used as a useful model for the research of origin or genesis mechanism of cancer stem cells and the treatment of relevant tumors.

Correlation of soil microbes and soil micro-environment under long-term safflower (Carthamus tinctorius L.) plantation in China.

Microbial community structure and ecological functions are influenced by interactions between above and belowground biota. There is an urgent need for intensive monitoring of microbes feedback of soil micro-ecosystem for setting up a good agricultural practice. Recent researches have revealed that many soils characteristic can effect microbial community structure. In the present study factors affecting microbial community structure and soil in Carthamus tinctorius plantations in arid agricultural ecosystem of northern Xinjiang, China were identified. The result of the study revealed that soil type was the key factor in safflower yield; Unscientific field management resulted high fertility level (bacteria dominant) of soil to turn to low fertility level (fungi dominant), and Detruded Canonical Correspondence Analysis (DCCA) showed that soil water content, organic matter, available N, P and K were the dominant factors affecting distribution of microbial community. Soil water content showed a significant positive correlation with soil microbes quantity (P < 0.01), while others showed a significant quantity correlation with soil microbe quantity (P < 0.05).