Spectral computed tomography (CT) has triggered a technological revolution in radiodiagnosis while demonstrating its increasing application value in radiotherapy. Employing dual-energy techniques for material decomposition, spectral CT provides optimized solutions for several critical aspects of radiotherapy. Based on a review of the application situation of spectral CT in radiotherapy, this study delved into spectral CT′s significant advantages in image quality improvement, precise dose calculation, and comprehensive quantitative assessment. Furthermore, this study envisioned the development orientations and application prospects of spectral CT.

Spectral computed tomography (CT) has triggered a technological revolution in radiodiagnosis while demonstrating its increasing application value in radiotherapy. Employing dual-energy techniques for material decomposition, spectral CT provides optimized solutions for several critical aspects of radiotherapy. Based on a review of the application situation of spectral CT in radiotherapy, this study delved into spectral CT′s significant advantages in image quality improvement, precise dose calculation, and comprehensive quantitative assessment. Furthermore, this study envisioned the development orientations and application prospects of spectral CT.

After organ transplantation, graft rejection is one of the most common complications, which will cause adverse injuries to grafts regardless of etiology. Tertiary lymphoid structures (TLS) occur in non-lymphoid tissues under pathological conditions. Identification and characterization of mechanisms regulating graft rejection can not only promote understanding of the survival and prognosis of organ grafts, but also provide ideas for treating graft rejection reaction.

Objective:To investigate the dosimetry effect of rotational errors of multi-channel cylinder vaginal applicator of intravaginal irradiation after surgery of endometrial cancer.Methods:A total of 18 patients who underwent surgery of endometrial cancer at Peking Union Medical College Hospital from June to December 2022 were selected.The plans of patients who adopted the treatment of multi-channel cylinder applicator of vagina were retrospectively analyzed,which maintained the same retained mode with clinical plan.The applicator was rotated clockwise by 22.5? and 45.0?,respectively,simulating the rotational errors that occurred in placing the applicator among clinical inter-fractions.And then,the changes of dosimetry of target area and organs at risk(OAR)under two kinds of rotation amplitudes were further analyzed.Results:When the applicator was rotated as 22.5?,the minimum doses to 90%volumes of CTV by 2.03%than that of clinical plan,which was significantly different(t=5.86,P<0.05),and the maximal doses to 2cc of OARs of bladder and rectum respectively increased 2.35%and 2.71%,and the differences of them were statistically significant(t=-3.49,-2.40,P<0.05),respectively.When the applicator was rotated as 45?,the D90 of the target area decreased by 5.75%than that of clinical plan,which was statistically significant(t=14.07,P<0.05).The D2cc values of the bladder and rectum increased respectively by 6.50%and 9.49%than that of clinical plan,which were statistically significant(t=-7.72,-6.9,P<0.05).The differences of the exposed doses of sigmoid colon and small intestine after the applicator was rotated by 22.5? and 45.0? between the plan and original plan were respectively less,which were not statistical significance.Conclusion:The multi-channel cylinder applicator can provide individualized dose distribution in intravaginal irradiation.However,attention should be paid to the placement of the applicator when patients undergo inter-fractional treatment,in order to avoid deviations in the angular alignment from the original plan.This can impact the dosages of the target area and OARs.

Objective:To analyze the differences in dosimetric quality and plan complexity of volumetric modulated arc therapy (VMAT) plans based on Halcyon 2.0 and Truebeam for different treatment sites of the patients.Methods:Halcyon 2.0 VMAT plans in head & neck, chest, abdomen, and pelvis treatment sites of 49 cases were retrospectively selected and the VMAT plans were re-designed based on Truebeam with the same optimization parameters. The differences in dosimetric metrics and plan complexity between the two types of plans were compared and analyzed. P<0.05 was considered as statistically significant. Results:In terms of PTV, Halcyon 2.0 plans showed better homogeneity index (HI), conformal index (CI) in the head & neck and chest. Besides, Halcyon 2.0 plans yielded better D 98% and CI in the abdomen and better D 2% in the pelvis. For organs at risk (OAR), the D 20% and D mean of bilateral lungs, and D meanof heart for Halcyon 2.0 plans in the chest were lower than those for Truebeam plans (all P<0.05). For the complexity metrics, the median average aperture area variability (AAV) of Halcyon 2.0 plans in the head & neck, abdomen and pelvis were 0.414, 0.425 and 0.432, which were better than 0.385, 0.368 and 0.361 of Truebeam plans in the corresponding sites, respectively. In the abdomen and pelvis, Halcyon 2.0 plans showed better median modulation complexity score (MCS) than Truebeam plans (0.320 vs. 0.268, 0.303 vs. 0.282; both P<0.05). The median small aperture score (SAS) for all plans of Halcyon 2.0 were better than that of Truebeam plans (all P<0.05), and the median plan average beam area (PA) of all plans of Halcyon 2.0 were larger than that of Truebeam plans (all P<0.05). Conclusions:Compared with conventional fractionated VMAT plans based on Halcyon 2.0 and Truebeam, Halcyon 2.0 plans have similar or even better dosimetric quality. However, Halcyon 2.0 plans have lower plan complexity, which makes it an advantage in clinical application.

Objective:To explore the feasibility of StereoPhan (SP) phantoms and SRS MapCHECK (SMC) semiconductor matrices in the dose verification of HyperArc (HA) plans for patients with brain metastases (BM).Methods:A total of 16 BM patients who received HA radiotherapy in the Peking Union Medical College Hospital were enrolled in this study. The ion chamber and the SMC semiconductor matrix were inserted into SP phantoms, respectively. The point and planar doses in HA verification plans were measured and compared with the calculated data of the treatment planning system (TPS). The criteria for planar dose γ analysis were set at 2 mm/3%, 2 mm/2%, 1 mm/3%, and 1 mm/2%.Results:The mean deviation of point doses in 16 patients was 1.33%±0.84%. Based on the above criteria, the γ pass rates of planar doses were 99.72%±0.46%, 98.93%±1.32%, 98.85%±1.79%, and 97.13%±3.19%, respectively.Conclusions:SP phantoms and SMC semiconductor matrices are applicable to the dose verification of HA plans for BM patients. The analytical criteria of 3% and 1 mm/2% can be used for verifying point and planar doses, respectively.

Tryptophan (TRP) is an essential amino-acid and the precursor of many signaling molecules. Under the catalysis of indoleamine 2, 3-dioxygenase, kynurenine pathway can form its metabolites uroquinolinic acid and quinolinic acid, which is the main channel of TRP metabolism.Through different mechanisms in N-methyl-D-aspartate receptor, they participate in nervous modulation, affect cognitive processes and play an important role in many central nervous system diseases development. Kynurenine pathway is different under physiological and pathological conditions. In addition, there are many rate-limiting enzymes in the kynurenine pathway, which can interfere kynurenine pathway. This article reviews the relationship between tryptophan/kynurenine pathway and cognitive dysfunction.

Objective:To study the feasibility of using pelvic iterative cone beam CT images for dose calculation of radiation therapy planning, so as to provide support for adaptive radiotherapy.Methods:The CIRS 062 M phantom was scanned by Varian Halcyon v2.0 o-ring accelerator, and the average CT number under different scattering conditions was calculated, and then the ICBCT-ED conversion curve was established. CT images of CIRS 002PRA pelvic IMRT phantom and ICBCT images at different positions were collected. Treatment plan using VMAT technique based on CT image was designed and transplanted into ICBCT image with dose recalculated. The differences of gamma passing rate among target volume, organs at risk and 3-dimensional dose were compared. Based on the actual treatment plan of patients, the differences of 3-dimensional dose gamma passing rate in 10 pelvic patients were analyzed retrospectively.Results:There was a large CT value deviation at central position between the isolated no-scattering condition and the full-scattering condition, and the maximum deviation was 144 HU. The CT values of other positions in full-scattering condition were similar to those of the central position, and the maximum deviation was less than 50 HU. Based on the calculated result of ICBCT images at different positions of the pelvic phantom, the dose deviation of the target volume or organs at risk was less than 1 Gy. Compared with the plan based on CT images, the average 3-dimensional dose gamma passing rate under the criteria of 1% dose difference (DD)/1 mm distance-to-agreement (DTA) and 2% DD/2 mm DTA in plan based on ICBCT images were (88.86 ±1.18)% and (98.38±0.89)%, respectively. The ranges of average 3-dimensional dose gamma passing rate under the criteria of 2% DD/2 mm DTA and 3% DD/3 mm DTA in 10 patients with pelvic tumors were 90.03%-95.43% and 93.58%-97.78%, respectively, and the worst result was only 85.90% and 92.90%, respectively. The main reason of the worst result was the dose difference caused by large variation of bladder contour due to over-filling.Conclusions:Under comprehensive scattering conditions, the ICBCT-ED conversion curve is reconstructed and the treatment plan can be designed by using the ICBCT image of Halcyon v2.0 linear accelerator. The accuracy meets the standards of clinical application, which provides assurance for adaptive radiotherapy in the future.

Objective To analyze the energy supply nutrients (protein,fat and lactose) and mineral elements (calcium,copper,iron,zinc,magnesium,sodium,potassium) supplied in breast milk from the resident of Lanzhou,and investigate the problems of those energy supply nutrients and mineral elements in breast milk of this population so that to provide basis for breast feeding.Methods Breast milk from 1 215 mothers whose babies were fed totally by the breast milk and grew well was collected and assayed for the contents of protein,fat,lactose,calcium,copper,iron,zinc,magnesium,sodium and potassium in Lanzhou region.The optimal range for breast feeding was set by normal distribution method.The results were compared with the breast milk from other internal region in order to clarify the contents difference.Results The prevalence of mother-milk-fed in this region was 48.5％.The normal ranges (unit:g/100 g) of fat,lactose and protein were 1.57-5.11,6.58-7.16 and 0.79-1.35,and the normal ranges of calcium,copper,iron,zinc,magnesium,sodium and potassium were 5.25-7.83 mmol/L,5.66-8.28 mmol/L,0.14-0.3 mmol/L,15-64.48 μmol/L,0.98-1.62 mmol/L,1.92-18.82 mmol/L,7.95～ 17.31 mmol/L in the high quality breast milk.Compared with the other internal region,the normal ranges of the protein,fat and lactose in Lanzhou were lower.The contents of protein,fat,lactose,calories,calcium,copper,zinc and sodium in the breast milk from the whole investigated population were significantly lower compared with breast milk of high quality (P＜0.01).Conclusion The quality of breast milk in Lanzhou is not so good.The contents of various nutrients in breast milk should be improved to a proper level by appropriate ways so that to improve the growth and development of the baby.

Objective To be good for the different working age midwives to carry out the same evaluation of the pregnant woman,we build and use the Episiotomy Evaluation Form for reducing the rate of episiotomy with ensuring the safety of mother and baby.Methods Consult relevant literature,combine clinical practice,discuss,report to the hospital ethics committee many times and at last it was made after approval.The details included:perineal lesions,perineum elasticity,perineal length,maternal coordination,gestational age,age,fetal distress degree,amniotic fluid situation,the weight of fetus estimated,the second time of labor and so on,to score by 0,1,3,5,20.A total of 600 patients with low risk of natural childbirth were randomly divided into observation group and control group according to method of random number table with 300 cases each.The observation group was graded according to the perineal incision evaluation and we operated according to its use method.The control group was judged according to the experience of midwife and subjective cognition.At last compared the effects on the mother and baby.Results The rates of lateral episiotomy and Ⅰ degree laceration were 15.00％ (45/300) and 63.00％ (189/300) in the observation group and 48.33％ (145/300) and 21.67％ (65/300) in the control group,respectively.The difference between the two groups was statistically significant (x2=16.238,21.507,P ＜ 0.05).There was no statistical difference in the perineal intact rate,median perineal incision rate,perineal Ⅱ degree laceration rate,severe perineal laceration,second stage of labor,postpartum hemorrhage 2 hours,neonatal asphyxia rate,incidence of neonatal birth injury (brachial plexus injury,clavicle fracture,etc.) and pelvic floor muscle strength of 42 days after delivery between the two groups (P ＞ 0.05).Conclusions By using the episiotomy evaluation form,we can improve the accuracy and homogeneity of the midwife's assessment about the episiotomy which is benefit to reduce rate of episiotomy.It is worth promoting in clinical practice but we should ensure the safety of maternal and child.