Objective
To preliminarily observe the clinical efficacy of hippocampal-sparing prophylactic cranial irradiation (HS-PCI) using helical tomotherapy (HT) in patients with limited-stage small-cell lung cancer (LS-SCLC) after chemoradiotherapy, and compare HT with intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) in dose distribution.
Methods
From April to June, 2014, six patients with LS-SCLC who had achieved a complete remission after chemoradiotherapy were assigned to HS-PCI using HT within a month after brain metastasis was ruled out using brain magnetic resonance imaging (MRI). After fusing CT images and MRI images, the hippocampus was contoured in the fusion images and hippocampal avoidance regions were created using a volumetric expansion of 3 mm around the hippocampus. A dose of 25 Gy in 10 fractions to 95%of planning target volume (PTV) was prescribed in HT, IMRT, and VMAT. The clinical efficacy, adverse reactions, neurocognitive function, and brain metastasis were evaluated for HT. The dose distribution in PTV and hippocampus were compared between HT, IMRT, and VMAT.
Results
There were one patient with abdominal wall and abdominal lymph node metastases, one patient with local recurrence, and no patient with brain metastasis during the observation period. The numbers of patients with grade 1 and grade 2 headache, dizziness, and hair loss reactions were 3 and 1, 3 and 1, and 4 and 2, respectively. There were no significant differences in the average score of the Mini-Mental State Examination before treatment and at 3and 6 months after treatment (29.7, 29.2, and 29.3; P=0.083, 0.317, and 0.157). The mean dose to the hippocampus was 16.85 Gy for IMRT and 17.59 Gy for VMAT. For HT, the mean doses to the hippocampus and avoidance regions were reduced to 5.26 Gy and 6.21 Gy, respectively. The prescribed dose for HT was reduced by 79% and 71% compared with IMRT and VMAT, respectively. The average coverage rate of the prescribed dose was 94.48% for HT.
Conclusions
HT achieves promising dose distribution and target coverage in sparing of the hippocampus. Moreover, HT dose not increase the incidence of adverse reactions. The change in neurocognitive function needs to be further studied with long-term observation and large-scale sampling.
Key words:
Carcinoma, small-cell lung, limited stage; Hippocampal-sparing prophylactic cranial irradiation; Helical tomotherapy; Neurocognitive function; Three-dimensional radiotherapy; Dosimetry
Abstract Background: Graves’ disease(GD) has a tendency for familial aggregation, but it is uncommon to occur in more than two generations. However, little is known about susceptibility genes for GD in the three-generation family. Methods: DNA were extracted from three-generation familial GD patient with a strong genetic background in a Chinese Han population. The Whole Exome Sequencing (WES) was utilized to screen the genome for SNVs associated with GD and the Sanger Sequencing was used to confirm the potential disease-causing genes. Results: In the case study, there were five patients with Graves’ disease(GD) from a three-generation family. The SNVs of MAP7D2 (c. 452C>T: p. A151V), SLC1A7 (c. 1204C>T: p. R402C), TRAF3IP3 (c. 209A>T: p. N70I), PTPRB (c. 3472A>G: p. S1158G), PIK3R3 (c. 121C>T: p. P41S), DISC1 (c. 1591G>C: p. G531R) were found to be associated with the familial GD and the Sanger sequencing had confirmed these variations. Furthermore, PolyPhen-2 score showed that the variants in TRAF3IP3 , PTPRB , PIK3R3 are more likely to change protein functions. Conclusion: The MAP7D2 , SLC1A7 , TRAF3IP3 , PTPRB , PIK3R3 , DISC1 may be the candidate susceptibility genes for familial GD from a three generations family.
Objective To study the dosimetrie effect of different ~(125)I seeds arrangements when implanted at the same number and activity (2.96×10~7 Bq) in a plane. Methods Nine different arrangements of ~(125)I seed plane implantation were established with the three-dimensional treatment planning system (TPS) and the isodose curves of 60, 80, 130, 145 and 200 Gy were figured out. The areas and radius in these isodose curves were calculated with the professional image analysis software. Results The areas and radius in the same isedose curves were dissimilar when the arrangement was different. The arrangements which had the maxima area in the 60, 80, 130, 145 and 200 Gy isodose curves were X1.5Y1.5, X1Y1.5, X1Y1(2)1.5, X1Y1, X1Y1(2) 0.5 with the area of 1641.91, 1166.42,791.09,718.27,474.63 mm~2 respectively. The seeds arrangement with the maximum area in the same isodose curve had a better dose distribution and there were no cold spots in the target. Conclusion The dose and therapeutic effect was influenced significantly by the arrangemeut of the seeds even the number and activity were equal.
Key words:
~(125)I seed; Dosiology; Brachytherapy; Isodose distribution
Anti-nutritional factors such as lectins, saponin, trypsin inhibitor and phytic acid are endogenous substances in the common bean (Phaseolus vulgaris L.). In this study, the contents or activities of these anti-nutritional factors in fresh pods were detected in 56 selected cultivars. The results revealed significant difference within each factor in the tested cultivar population. The mean value of lectin content and the activity of trypsin inhibitor were 1.743 mg ⋅ g−1 and 1.680 mg ⋅ g−1 respectively. Their coefficients of variation (CV) were both more than 100% and each of the cultivar frequency distribution curve showed a main peak, but the discontinuous distributions in the extremely high and low areas indicate hierarchic cultivars. However, the mean contents of saponin and phytic acid were 3.730 mg ⋅ g−1 and 3.102 mg ⋅ g−1, respectively, with CV less than 41%. Each showed a main peak in its normal distribution curve and low frequency continuous distribution in dual tails. Meanwhile, statistic analysis demonstrated a positive correlation between the lectin content and trypsin inhibitor activity in fresh pods. Furthermore, all 56 tested cultivars were clustered into three groups based on their four anti-nutritional factor levels: 80% of them into medium level group, and 12% of them into low level group. The endogenous edible toxic compounds, such as lectin and trypsin inhibitor, are closely related to insect resistance in the field. This study suggests that it is possible to screen the cultivars containing less lectin and other factors but with reduced pest resistance in the field.
Objective
To use clustering analysis to help physicians detect abnormal parameters in radiotherapy treatment plans and improve the efficiency of plan verification.
Methods
From 2010 to 2015, 835 breast cancer treatment plans for using 4-field hybrid intensity-modulated radiotherapy from MOSAIQ were collectted. Fractional dose, beam angle, and monitor unit were used as featured parameters of a treatment plan to generate a dataset. The K-means clustering algorithm based on principal component analysis was used to perform a clustering analysis of the dataset and divide the dataset into different clusters. The outliers of clusters were automatically detected based on the distance threshold. The outlier-contained treatment plans were manually verified by physicians to determine the accuracy of clustering analysis in detection of abnormal plans.
Results
In the clustering analysis, the sample space composed by parameters of treatment plans for breast cancer was divided into 4 clusters, 3 of which had outliers detected. In the targeted treatment plans, 3 plans became outliers because of special target volume and the other 4 plans needed improvement.
Conclusions
Clustering analysis is effective to help physicians to independently verify treatment plans.
Key words:
Clustering analysis; Outlier detection; Radiotherapy treatment plan; Independent check
Previously, a case series study was conducted on our part in which 5 patients with Graves' disease (GD) were collected from a 3-generation family to screen for susceptibility genes responsible for GD. The single nucleotide variants of Microtubule-associated protein 7 domain containing 2 c. 452C > T, p. Ala151Val, Solute carrier family 1 member 7 c. 1204C > T, p. Arg402Cys, tumor necrosis factor receptor-associated factor 3 interacting protein 3 (TRAF3IP3) c. 209A > T, p. Asn70Ile, protein tyrosine phosphatase receptor type B (PTPRB) c. 3472A > G, p. Ser1158Gly, Phosphoinositide-3-kinase regulatory subunit 3 c. 121C > T, p. Pro41Ser, disrupted in schizophrenia 1 (DISC1), c. 1591G > C p. Gly531Arg were associated with the familial GD. We then further confirmed these variants and investigated whether other mutations render susceptibility to GD. The case-control study collected patients with sporadic GD or no GD family history. A snapshot program was used for genotyping the selected SNPs in 235 GD patients (GD group 1) and 284 healthy patients (control group). Furthermore, another 184 GD patients were recruited (GD group 2) to sequence the specified exons of these genes. The sequenced data was compared with Chinese Millionome Database (CMDB). Several variants of PTPRB, phosphoinositide-3-kinase regulatory subunit 3, TRAF3IP3, and DISC1 were found in GD group 2 but not in CMDB. Moreover, the allele frequency of SNP rs2076150 (TRAF3IP3) and rs2492367 DISC1 in GD group 2 was significantly higher than that of in CMDB (all P < .05). When the control group or CMDB was set as a reference group, a significantly higher frequency in alter allele C of SNP rs186466118 PTPRB was observed in GD group 1 and GD group (constituted by GD group 1 and GD group 2). Equally importantly, there was a correlation between the allele C of SNP rs186466118 and the increased risk of GD susceptibility (all P < .05). PTPRB, TRAF3IP3, and DISC1 may be susceptibility genes for GD, and more variants of PTPRB, TRAF3IP3, and DISC1 were found in GD patients.
Objective:Megavoltage computed tomography (MV-CT) is used for setup verification and adaptive radiotherapy in tomotherapy. However, its low contrast and high noise lead to poor image quality. This study aimed to develop a deep-learning-based method to generate synthetic kilovoltage CT (skV-CT) and then evaluate its ability to improve image quality and tumor segmentation.Approach:The planning kV-CT and MV-CT images of 270 patients with nasopharyngeal carcinoma (NPC) treated on an Accuray TomoHD system were used. An improved cycle-consistent adversarial network which used residual blocks as its generator was adopted to learn the mapping between MV-CT and kV-CT and then generate skV-CT from MV-CT. A Catphan 700 phantom and 30 patients with NPC were used to evaluate image quality. The quantitative indices included contrast-to-noise ratio (CNR), uniformity and signal-to-noise ratio (SNR) for the phantom and the structural similarity index measure (SSIM), mean absolute error (MAE), and peak signal-to-noise ratio (PSNR) for patients. Next, we trained three models for segmentation of the clinical target volume (CTV): MV-CT, skV-CT, and MV-CT combined with skV-CT. The segmentation accuracy was compared with indices of the dice similarity coefficient (DSC) and mean distance agreement (MDA).Mainresults:Compared with MV-CT, skV-CT showed significant improvement in CNR (184.0%), image uniformity (34.7%), and SNR (199.0%) in the phantom study and improved SSIM (1.7%), MAE (24.7%), and PSNR (7.5%) in the patient study. For CTV segmentation with only MV-CT, only skV-CT, and MV-CT combined with skV-CT, the DSCs were 0.75 ± 0.04, 0.78 ± 0.04, and 0.79 ± 0.03, respectively, and the MDAs (in mm) were 3.69 ± 0.81, 3.14 ± 0.80, and 2.90 ± 0.62, respectively.Significance:The proposed method improved the image quality of MV-CT and thus tumor segmentation in helical tomotherapy. The method potentially can benefit adaptive radiotherapy.
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