RESUMO
Objective To compare the dosimetric differences between free-hand method and virtually optimized method for implanting needles in intracavitary and interstitial combined brachytherapy (IC/IS BT) of cervical cancer,and to explore the improvement space of the existing interstitial brahcytherapy plan.Methods High-dose-rate cervical cancer IC/IS BT plans (short for Treatment-Plan) of 18 cases were retrospectively analyzed.For each treatment plan,Nucletron Oncentra 3D brachytherapy planning system was utilized to redesign the virtually optimized insertion method IC/IS BT plan (short for Optimized-Plan).Dose volume histogram was adopted to evaluate the dose distribution in high-risk clinical target areas and exposure dose to organ at risk (OAR).The plan execution efficiency between two plans was also assessed.Results Comparing these two plans,the differences in conformity and uniformity of dose distribution of the target area were statistically significant (P=0.000,0.008).The differences of D0.01 cm3,D1 cm3,D2 cm3 and D5 cm3 in bladder,rectum,sigmoid and small bowel were all statistically significant (all P＜0.05).Optimized-Plan could reduce the D2 cm3 of bladder,rectum,sigmoid and small bowel by 60.41,36.43,27.53 and 12.43 cGy,respectively.The execution time for the Treatment-Plan and Optimized-Plan were (857.92±243.39) s and (804.53±239.13) s with statistical significance (P＜0.001).Conclusions Compared with the free-hand method,virtually optimized method yields more conformable coverage of the target area and more uniform dose distribution.At the same time,the doses of each OAR are reduced to different degrees and the execution time of the plan is also shortened.
RESUMO
Objective: In T_(739) inbred line mice,bladder cancer model was established via tumor source transplant.In order to get insights of the biological effects of implanting ~(125)I seed to treat bladder cancer,the development and the pathological modality of tumor tissues were observed through the experiment of implanting ~(125) I seed.The experiment was to provide theoretical gist and practical guidance for clinical(utilization) of ~(125)I seed for brachytherapy of bladder cancer. Methods: 16 T_(739) inbred line mice were divided into two groups(A:experimental group,n=8;B:control group,n=8) in random;bladder cancer model was established via tumor source transplant.When the diameter of the transplanting tumor was about 0.7 cm,~(125)I seeds were implanted at the tumor of experimental group while the empty seed was penetrated into the control group at the same position as the experimental group and the experimental mice were executed after 24 days.The longest vertical diameters(a) and(b) of tumor body were observed every 3 days and the volume of tumor body(V=ab~(2)/2) was calculated.Combining with the weight of mouse(W) and the weight of tumor body after execution of mice(w),the growth curve of tumor was protracted and the colony redouble time and tumor suppression rate were calculated.After fixation of formaldehyde,the pathological modality of tumor tissues were observed with HE staining. Results: ① The transplantation was 100% successful and there was no natural fade-away phenomenon.②After implantation of seed,the weight of group A mice increased by(4.93?0.60)g,and group B increased by(13.60?1.15)g(P