Objective:To explore the expression of growth differentiation factor-15 (GDF-15) in different pathological types of prostate cancer, and to analyze the impact of GDF-15 on biochemical recurrence of prostate cancer after radical prostatectomy.Methods:A retrospective analysis was conducted on the case data of 138 patients with prostate cancer who underwent radical prostatectomy at the 363rd Hospital from January 2019 to January 2022. The patients were divided into the recurrence group ( n=46) and the non-recurrence group ( n=92) based on postoperative biochemical recurrence. Measurement data were expressed as mean±standard deviation ( ± s), and analysis of variance was used for comparisons among multiple groups, while t-test was used for comparisons between two groups. Count data were expressed as the number of cases and percentages, and the Chi-test was used for comparisons between groups. Stratified regression analysis was used to explore the relationship between GDF-15 and different clinical pathological characteristics. By combining spline functions and Logistic regression analysis, the restricted cubic spline model was used to analyze the effect of GDF-15 on biochemical recurrence of prostate cancer in different pathological types. Kaplan-Meier survival curves were drawn to visually display the recurrence differences of prostate cancer patients at different GDF-15 levels. Results:The expression level of GDF-15 was the lowest in Gleason grade group (GGG)1 type at (548.71±78.25) pg/mL, and the highest in GGG5 type at (916.75±94.33) pg/mL, and the difference was statistically significant ( F=87.39, P<0.001). The level of GDF-15 was positively correlated with prostate-specific antigen (PSA), GGG5 type, and vascular endothelial growth factor (VEGF) ( P=0.029, 0.022, 0.015). The levels of PSA, GDF-15, Gleason score, alkaline phosphatase (ALP), C-reactive protein (CRP)/albumin (ALB), VEGF, and the proportion of TNM stage Ⅲ-Ⅳ, lymph node invasion, seminal vesicle invasion, nerve invasion, capsule rupture, and GGG5 type in the recurrence group were significantly higher than those in the non-recurrence group, the differences were all statistically significant ( P<0.05); the lymphocyte-to-monocyte ratio (LMR) was significantly lower than that in the non-recurrence group, and the difference was statistically significant ( P<0.001). GDF-15 had a non-linear dose-response relationship with the biochemical recurrence risk value. The risk value is significantly positively correlated with the level of GDF-15, and this relationship was not affected by the type of prostate cancer pathology. In patients with GGG1 to GGG5 types of prostate cancer, when the GDF-15 levels were >720, 700, 690, 650, and 610 pg/mL, respectively, the risk values increased as the GDF-15 levels rose. The Kaplan-Meier survival curve analysis showed that as the level of GDF-15 increased, the recurrence rate of patients significantly rose. Conclusions:The expression level of GDF-15 expression is the lowest in GGG1 type and the highest in GGG5 type. Both GDF-15 and GGG5 type are the independent risk factors for biochemical recurrence after radical prostatectomy, and GDF-15 exhibits a significant positive nonlinear dose-response relationship with the risk of biochemical recurrence.

Objective:To investigate the impact of carbon based non-conductive sliding rails on intensity-modulated radiation therapy (IMRT) planning for vertebral tumors.Methods:A reconstruction imaging of the couch plate and its rails removed from the EDGE linear accelerator was acquired by helical computed tomography (CT), and pushed into the treatment planning system (TPS). Based on CT images of homogeneous phantom and patients in our database, 6 and 10 MV photon IMRT plans were designed with five fields (180°, 200°, 220°, 160°, 140°), setting a prescribed dose of 3 Gy/F ×10 F to the planning target volume (PTV), and the dose was calculated by AcruosXB. In addition, optimization plans (OP) without rails and with rails symmetrically moving (4-19 cm, step size 1 cm) were created and verification plans(VP) were created by inserting and removing slide rail′s structure from the corresponding OP in VP. The differences in mean dose ( Dmean), homogeneity index (HI), and conformability index (CI) of the PTV, and maximum dose ( Dmax) of the spinal cord were compared and analyzed between the VP and OP. Results:HI of PTV with and without the rails were worse in the 6/10 MV verification plans, with a maximum difference of 2%. In 6 MV plans, with rails Dmean of PTV decreased by (2.07±0.99)%, CI increased by (4.91±3.12)%, and Dmax of spinal cord decreased by (1.83±1.37)%. Without rails, the Dmean of PTV increased by (2.02±0.96)%, but CI decreased by (3.07±1.31)% and Dmax of the spinal cord increased by (2.03±1.44)% in the patient respectively. There were significant statistical differences between groupswith and without rails( F=27.55, 361.32, 13.05, P<0.05). The target volume Dmean and spinal cord Dmax decreased with a sloping " W" with the change of the rail position. The difference appeared to be noticeable in the range of less than 10 cm, but it gradually decreased as the rails slid to the outside until it reached zero, and the Dmean of PTV and Dmax of the spinal cordchanges were less in 10 MV plans, comparing to 6 MV plans. Conclusions:The dose attenuation by the sliding rails of the Qfix kVue should not ignored in the IMRT of spinal metastases and the slide position should be consistent with the planned position.

Objective:To evaluate the difference of dosimetry between three-dimensional and two-dimensional plans based on CT images of occult perforation in brachytherapy of cervical cancer, aiming to provide clinical reference.Methods:A total of 817 patients with cervical cancer received simple intrauterine (intrauterine tandem plus vaginal colpostats) three-dimensional brachytherapy in Chongqing University Cancer Hospital from January 2019 to December 2020 were retrospectively reviewed. Among them, 16 patients had occul uterine perforation. Based on Oncentra Brachy Therapy plan system, the single prescription dose was 6Gy. Three-dimensional (3D group) and two-dimensional (2D group) plans were designed on the perforated CT images The target volume, conformal index (CI), conformal index coformity index (COIN) and organs-at-risk (OAR) D 2cm 3 parameters were used to assess the plans between two groups. Results:The incidence of pccult uterine perforation was 1.96%(16/817) during brachytherapy for cervical cancer. The volume of prescription dose curve in the 3D group was (40.74±14.98) cm 3, significantly smaller compared with (91.46±19.71) cm 3 in the 2D group ( P<0.05), whereas the volume of the high-risk clinical target area wrapped by prescription dose curve did not significantly differ between two groups ( P>0.05). The CI and COIN in the 3D group were 0.79±0.10 and 0.72±0.96, significantly higher compared with 0.38±0.09 and 0.37±0.18 in the 2D group (both P<0.05). The D 2cm 3 of bladder, rectum, sigmoid colon, small intestine in the 3D group were (306.06±77.57) cGy, (252.27±72.60) cGy, (127.25±62.84) cGy and (228.79±94.90) cGy, significantly lower than (548.03±164.21) cGy, (411.16±118.74) cGy, (227.45±94.48) cGy and (450.95±157.96) cGy in the 2D group (all P<0.05). Conclusions:Application of image guidance in brachytherapy of cervical cancer is helpful to detect occult uterine perforation. When occult uterine perforation occurs, the use of three-dimensional plan can basically meet the clinical needs, which is significantly better than the two-dimensional plan.

Objective:To monitor and evaluate in vivo dose changes of intensity-modulated radiotherapy (IMRT) in patients with cervical cancer in a real-time manner. Methods:Twelve patients with cervical cancer admitted to our hospital were enrolled in this study. The in vivo doses were monitored by PerFRACTION?. Electronic portal imaging device (EPID) were collected in each treatment fraction for two-dimensional in vivo dose verification[γ index and dose difference (DD) index]. Log files were recorded for three-dimensional in vivo dose verification (γ index). The correlation between in vivo dose and treatment duration was analyzed by Pearson correlation analysis. Results:A total of 206 sets of EPID images and corresponding Log files were collected. The three-dimensional in vivo dose verification γ 1%/1mm of all patients was not correlated with treatment fraction ( P>0.05). Among them, the absolute difference of γ 1%/1mm of 94.66% fractions was< 1%. The mean DD 3% of two-dimensional in vivo dose verification of all patients was negatively correlated with treatment fraction ( P<0.05). Among which, the average γ 3%/3mm of 9 patients was>89% in the treatment fractions, and the average γ 3%/3mm of 98.57% fractions of these 9 patients was>93%. The other 3 patients had an average γ 3%/3mm ranged from 38% to 100%. CBCT images showed that the bladder volume of these 3 patients was significantly decreased with the relative changes by 82.08%, 84.41% and 73.59%, respectively, and the target area was retracted significantly with the relative changes by 38.12%, 59.79% and 24.46%, respectively. Conclusion:Combined with γ index and DD index, PerFRACTION? can monitor the mechanical stability of accelerator and MU delivery accuracy during treatment fractions, and monitor the changes of in vivo dose in patients with cervical cancer, which can improve the safety and quality assurance of IMRT for cervical cancer patients and provide guidance for patients with adaptive radiotherapy.

Objective To study the effect of the uncertain deflection of the Delta4 phantom (ScandiDos AB,Sweden) in setting up on the Gamma index passing rate during the VMAT plan verification.Methods Two patients with head and neck cancer,two with lung cancers and one with pelvic cancer receiving VMAT radiotherapy were randomly chosen.By means of Eclipse8.6 TPS the treatment plans elaborated for the five patients were picked up to make the verification plans and Delta4 was used to perform dose verification On VARIAN Clinac Ⅸ.The Delta4 phantom was precisely set up first,and then it was deflected in a given angle towards the horizontal direction in relation to the center of the linear accelerator isocenter to perform the dose verification for 11 times successively.To figure out the relationship between the deflection angle of the Delta4 phantom and the Gamma index passing rate.Results As the Delta4 phantom was deflected by 0.0°,0.2°,0.4°,0.6°,0.8°,1.0°,1.2°,1.4°,1.6°,1.8° and 2.0° in sequence,the measured Gamma index passing rates presented a slight decline,but all greater than 90％ (DD 3％,DTA 3 mm).Conclusions In the VMAT plan verification,the Gamma index passing rate of Delta4 has no dependence on the uncertain deflection of the Delta4 phantom provided that the uncertain deflection of the Delta4 phantom is no greater than 2°,but the passing rates of DD and DTA vary significantly with the uncertain deflection of the Delta4 phantom.

High intensity focused ultrasound (HIFU) is a very complex transient process and can cause tissue coagulation necrosis. The cavitation and boiling behaviour of bubbles in the focal region play very important roles throughout an injury process. This paper reviews the research done by domestic and foreign scholars on behaviours of bubbles in HIFU irradiation process and summarizes in the focal region bubble cavitation and boiling generation, related detective means and relationships with hyperecho, temperature rise of the focus and injury shape.
Biophysical Phenomena ; High-Intensity Focused Ultrasound Ablation ; methods ; Humans ; Thermal Conductivity ; Thermodynamics

Objective To assess the diagnostic value of contrast enhanced ultrasound (CEUS) in liver metastases. Methods Thirty-six patients were examined with conventional ultrasonography, then underwent continuous real-time CEUS with low mechanical index. The size, location, number and perfusion patterns of liver metastases were evaluated. Results In 36 patients, 67 liver metastases were found with conventional ultrasound and 106 liver metastasis were found with CEUS. The perfusion patterns of lesions were in four types: ①Thirty-seven lesions (34.91%) showed as total enhancement during the early arterial phase and hypoechoic appearance during the portal venous phase and the late phase;②Fifty-six lesions (52.83%) showed a peripheral rim-like hyperechonic enhancement during the arterial phase and fast wash-out in the portal phase;③Twelve lesions (11.32%) showed as isoechoic enhancement during the arterial phase and the portal phase and was hypoechoic in the late phase;④One lesion (0.94%) showed hypoechoic appearance during all phases. The dimension of the lesions played an important role in the perfusion patterns. Conclusion The enhancement pattern and time of lesions are closely correlated with the tumor arterial supply. CEUS has high value in diagnosing liver metastases.