An improved formula considering the deformation effect for the α -decay half-lives is proposed based on WKB barrier penetrability. Using the quadrupole deformation values of the daughter nuclei obtained from the WS4 and FRDM models in the improved formula, the root mean square deviation (RMSD) between the calculated results and experimental data decreased from 0.456 to 0.413 and 0.415, respectively. Although the improved formula did not significantly reduce the overall RMSD, it produced results that better matched the experimental values for nuclei with larger deformations. Additionally, eXtreme Gradient Boosting (XGBoost) models were employed to further reduce the deviations between the calculated α -decay half-lives and experimental data, with the corresponding RMSDs decreasing from 0.413 to 0.295 and from 0.415 to 0.302, respectively. Furthermore, the improved empirical formula and XGBoost models were used to predict the α -decay half-lives of nuclei with Z = 117, 118, 119, and 120. The results suggest that N = 184 is the magic number.

The particle-number-conserving (PNC) method in the framework of the deformed shell model is employed to study the properties of the newly discovered short-lived neutron-deficient nucleus 224Np and its alpha decay. The calculated energy of the alpha particle lies within 300 keV of the experimental data. This is the first application of the PNC method to the region of neutron-deficient nuclei. This work provides the first attempt to combine the microscopic PNC theory with empirical formulas to study the nuclear alpha decay. The configurations of ground states are assigned as n5/2-[523] (R) v5/2+[633] for 224Np, n1/2-[530] (R) v3/2+[642] for 220Pa, n3/2+[651] (R) v1/2-[501] for 216Ac, and n7/2-[514] (R) v3/2-[501] for 212Fr. The proton subshell at Z = 92 disappeared in 224Np. Low-lying excited states are predicted for nuclei along the alpha-decay chain by the PNC method. Based on the PNC predicted alpha-decay energy and the assigned configurations, the alpha-decay half-lives are calculated by the empirical formulas, in which the angular momentum taken away by the alpha particle is taken into account. The angular momentum has an important effect on the alpha-decay half-life. The errors of the empirical formula calculation are of two orders of magnitude with the experimental data.

In this study,we systematically investigate the α-decay half-lives of 195 even-even nuclei using a de-formed two-potential approach(TPA).The cosh potential with fixed diffuseness parameter is adopted as the nuclear potential,for which deformation parameters are taken from the FRDM,WS4,and DRHBc models.The root mean square deviation(RMSD)decreases from 0.515 to 0.385,0.401,and 0.436,respectively,indicating that incorporat-ing nuclear deformations enables the deformed TPA to accurately reproduce experimental α-decay half-lives.Fur-thermore,by fitting the diffuseness parameter across various mass regions,the RMSD is further reduced,from 0.385 to 0.330,0.401 to 0.343,and 0.436 to 0.363.Additionally,the deformed TPA,combined with the fitted diffuseness parameter,is extended to predict the α-decay half-lives of even-even nuclei with Z=118 and 120.The results sug-gest that N=184 may be the next neutron magic number,following N=126.

An improved formula including shell closure effects is proposed to investigate alpha-decay half-lives. The coefficients of the improved formula are obtained by fitting the experimental alpha-decay half-lives of 677 nuclei with 62 <= Z <= 118. The root mean square deviation between alpha-decay half-lives calculated by the improved formula and experimental data is reduced from 0.435 to 0.385. The result indicates that the improved formula considering the shell closure effects is reliable in reproducing the experimental alpha-decay half-lives. In addition, the improved formula is extended to predict alpha-decay half-lives of nuclei with Z=119, 120 isotopes. The results of the predicted alpha-decay half-lives indicate that N=184 appears to be the next magic number beyond N=126.

Artificial neural networks (ANNs) can be used to learn complex representations of data, enabling new approaches to modeling and processing in the physical sciences. In this work, ANNs are employed to calculate the alpha-decay half-lives of nuclei. An improvement in the predictive power of the ANN models can be achieved by incorporating the angular momentum transferred by alpha particle and the quadrupole deformation of parent nuclei. Consequently, the root-mean-square deviation between the ANN-predicted alpha-decay half-lives and the experimental data is reduced from 0.581 to 0.334. Predictions are made for the alpha-decay half-lives of isotopes with Z = 117, 118, 119, and 120. Based on the characteristics (or systematics) of the alpha-decay half-lives, we propose that N = 184 is a closed neutron shell beyond N = 126.

AbstractThis study employed a commercial software velocity to perform deformable registration and dose calculation on deformed CT images, aiming to assess the accuracy of dose delivery during the radiotherapy for lung cancers. A total of 20 patients with lung cancer were enrolled in this study. Adaptive CT (ACT) was generated by deformed the planning CT (pCT) to the CBCT of initial radiotherapy fraction, followed by contour propagation and dose recalculation. There was not significant difference between volumes of GTV and CTV calculated from the ACT and pCT. However, significant differences in dice similarity coefficient (DSC) and coverage ratio (CR) between GTV and CTV were observed, with lower values for GTV volumes below 15 cc. The mean differences in dose corresponding to 95% of the GTV, GTV-P, CTV, and CTV-P between ACT and pCT were − 0.32%, 4.52%, 2.17%, and 4.71%, respectively. For the dose corresponding to 99%, the discrepancies were − 0.18%, 8.35%, 1.92%, and 24.96%, respectively. These differences in dose primarily appeared at the edges of the target areas. Notably, a significant enhancement of dose corresponding to 1 cc for spinal cord was observed in ACT, compared with pCT. There was no statistical difference in the mean dose of lungs and heart. In general, for lung cancer patients, anatomical motion may result in both CTV and GTV moving outside the original irradiation region. The dose difference within the original target area was small, but the difference in the planning target area was considerable.

Objective:To design a method to introduce random six-dimensional setup error (6D-SE) into the intensity-modulated radiotherapy (IMRT) planning for rectal cancer and evaluate its dosimetric effect.Methods:A total of 21 IMRT plans for patients with rectal cancer were randomly selected as reference plans [2 Gy per fraction for a total of 50 Gy; a 5 mm uniform margin around the clinical target volume (CTV) was taken as the planning target volume (PTV)]. For each fraction of the reference plan, a randomly generated 6D-SE was introduced by adjusting the geometrical parameters of the radiation field, and the dose was recalculated. The overall dose distribution with 6D-SE was obtained by adding up the dose of each fraction. A treatment simulation program that could complete the above workflow was developed using the Varian Eclipse scripting API (ESAPI). 6D-SEs that obey two preset distributions [distribution 1: translational error obey N(0, 4 2), and rotational error obey N(0, 2 2); distribution 2: translational error obey N(0, 2 2), and rotational error obey N(0, 1 2)] were introduced into the reference plans, and the dosimetric effects were assessed. Results:When the reference plans, error distribution 1, and error distribution 2 were applied, the Dmin values of the CTV were (49.4±0.41), (47.56±0.76), and (49.17±0.64) Gy, respectively; the D98% values of the CTV were (50.23±0.07), (49.98±0.10), and (50.27±0.09) Gy, respectively; the D98% values of the primary target area (the kernel part of the target area, excluding the margins) were (50.25±0.08), (50.42±0.13), and (50.33±0.10) Gy, respectively; the D98% values of the marginal area were (50.22±0.10), (49.88±0.11), and (50.26±0.10) Gy, respectively. In addition, compared with the result of the reference plans, the result of errors 1 and 2 showed no significant changes in the mean dose of the bladder and femoral heads ( P>0.05), despite slight decreases in the conformity index of the dose distribution with limited clinical significance. Conclusion:The proposed method and the treatment simulation program developed thereupon can introduce the 6D-SE obeying different distributions into the IMRT plans for rectal cancer on demand and provide overall dosimetric changes.

We build and train an artificial neural network (ANN) model based on experimental α-decay energy (Qα) data. In addition to decays between the ground states of parent and daughter nuclei, decays from the ground states of parent nuclei to the excited states of daughter nuclei are also included. In this way, the number of samples is increased dramatically. The α particle is assumed to have a spherical symmetric shape. The root-mean-square deviation between the calculated results obtained from the ANN model and the experimental data is 0.105 MeV. It shows a good predictive power for α-decay energy with the ANN model. The influence of different inputs is investigated. It is found that both the shell effect and the pairing effect result in an obvious improvement of the predictive power of the ANN model, and the shell effect plays a more important role. The optimal result can be obtained when both the shell and pairing effects are considered simultaneously. The application of the ANN model in predicting α-decay energy indicates a neutron magic number at N=184 in the superheavy nuclei mass region.

Objective To compare and analyze the dosimetric discrepancy of combind intracavitary/interstitial brachytherapy using three different kinds of optimization method in locally advanced cervical cancer.Methods Totally 20 cases of locally advanced cervical cancer were selected and divided into three groups according to different optimization method which include manual optimization group (MO) based on graphical optimization,inverse planning simulated annealing (IPSA 1)based on simulated annealing optimization algorithm,IPSA 2 based on IPSA 1 with limitation on maximum dose of target.The dose volume histogram parameters of the targets (V200,V150,V100,D100,D90,HI) and the OARs(D0.1 cm3,D1 cm3 and D2 cm3) were analyzed.Results For CTV,compared with MO,there was no significantly statistical difference in D100between IPSA 1 and IPSA 2(P ＞ 0.05).However,V200,V150,V100 and HI for ISPA1 were better than for ISPA2 (t =-3.422-9.910,P ＜ 0.05).In addition,V100 and D100 in ISPA1 were better than in ISPA2 (t =7.238,5.032,P ＜0.05).For OARs,D0.1 cm3,D1 cm3 and D2 cm3 in rectum,bladder,sigmoid colon of both ISPA 1 and ISPA 2 were dramatically lower than those of MO (t =2.235 5.819,P ＜ 0.05),without significantly statistical difference found between ISPA1 and ISPA2.Conclusions For combined intracavitary/interstitial brachytherapy in locally advanced cervical cancer,all treatment plans based on three different kinds of optimization methods can meet the clinical need.Moreover,inverse optimization can ensure dose coverage over target and reduce maximum dose of rectum,bladder and sigmoid colon.

[目的]测试与评估ABAS自动勾画软件用于头颈部肿瘤危及器官 (OAR) 自动勾画的剂量学精度.[方法]选取40例已行调强放疗 (IMRT) 治疗的头颈部肿瘤患者作为ABAS软件的测试对象, 将其放疗计划导入至单模板即一对一和多模板即十对一的两种方式下自动勾画OAR的CT图像上, 与手工勾画OAR的原始计划进行剂量学比较.[结果]单模板和多模板自动勾画方式下得到的OAR剂量分布均能达到临床对OAR剂量限制要求.其中, 单模板自动勾画与手工勾画下OAR剂量分布的统计学差异集中在左/右腮腺V30、脊髓Dmax、左/右颞叶Dmean、左/右视神经Dmax和视交叉Dmax (t=-3.491、-3.213、-4.673、-6.530、-6.544、2.115、3.175、2.121;P=0.001、0.003、＜0.001、＜0.001、＜0.001、0.041、0.003、0.040);多模板自动勾画与手工勾画下OAR剂量分布的统计学差异表现在脊髓Dmax、右视神经Dmax、左/右颞叶Dmean (t=-6.387、2.363、-6.058、-6.158;P＜0.001、0.023、＜0.001、＜0.001) .[结论 ]基于图谱库的ABAS自动勾画软件, 对于头颈部肿瘤调强放疗所关注的大部分OAR能够得到满意的剂量分布, 其中以多模板的OAR剂量分布与手工勾画OAR的原始计划最为接近, 在缩短临床医师器官勾画时间的基础上, 保证了自动勾画的剂量学精度.

Objective:To study the application of atlas-based autosegmentation (ABAS)software in the adaptive radiation therapy of nasopharyngeal carcinoma(NPC),and to evaluate the accuracy of organs at risk auto-contoured by the ABAS software.Methods:Fifteen NPC patients were selected randomly.There were three groups of CT images.CT1 was the planning CT.CT2 was the rescanned CT images when patients finished 2/3 radiation therapy treatment.Wheu patients finished the treatment,a new CT image date set was taken (CT3).The CT1 was set to be the model in ABAS software and the OARs were contoured automatically on CT2 and CT3 image sets.The Dice similarity coefficient(DSC)and contouring time were used to evaluate ability of ABAS software.Results:The average of DSC large volume OAR was ＞ 0.9.The spinal cord had the highest DSC (0.96 ± 0.01) while the lowest was lens(0.43 ± 0.19) between the first and second images.Similarly mandibular bone had the highest DSC (0.93 ±0.45)while lens had the lowest DSC(0.49 ± 0.17)between the first and third images.It took about ten minutes to accomplish the autocontouring with ABAS software.Conclusion:ABAS software had the excellent ability to contour OARs automatically during NPC adaptive radiation therapy.It had well accuracy and saved a lot of time.ABAS software could help to evaluate the dose to OAR during NPC radiation therapy quickly,and it was useful to NPC adaptive radiation therapy.

Objective To evaluate the application of atlas-based autosegmentation (ABAS) software for adaptive radiation therapy in cervical cancer.Methods Twenty-one patients were enrolled from January to March in 2014.In addition to the planning CT (pCT) images,first re-planning CT (rCT) image set was acquired during the radiotherapy course.The targets and regions of interested (ROI) were outlined on the pCT and rCT by experienced physicians.All contours were transmitted to Pinnacle treatment planning system in DICOM format,which contained both automatic and manual contouring.The dice similarity coefficient (DSC) and delineation volume were used to evaluate the quality of contours which obtained automatically from the software and manual contouring.Results The average values of DSC for automatic and manual contours were both larger than 0.7.The maximum (Max) DSC value was 0.89 ± 0.08 in clinical target volume (CTV),and the minimum (Min) was 0.72 ± 0.16 in gross tumor volume (GTV) for the target.For the ROIs,the Max DSC value was 0.88 ±0.05 in right femoral head,and the Min was 0.73 ± 0.07 in rectum.ABAS contouring volume was less than manual contouring on iliac bone,and there was statistical difference for the contour volume (t =3.37,2.74,P ＜ 0.05).There was no statistically significant difference for other contours volume.Conclusions ABAS software might shorten the time of clinical organ delineation work in cervical cancer radiotherapy,and have shown the advantage in adaptive radiation therapy technology.