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ObjectiveTo study the relationship between tumor siza,aource intensita,arescription dose and source dwell time in the after-loading treatment plaa,and to establish a method that can be used for rapid quality control of after-loading plans.Methods The all of gynecological cancer patients treated in this hospital were selected:84 cases of all three tubes of Fletcher applicator,58 cases of uterine alone and 39 cases of vaginal applicator.Each patient was scanned with CT before treatment.Contouring the target and organs at risa,ahe treatment plan was optimized using IPSA.Record the source strengta,arescription dosa,aource dwell tima,and tumor volume of the prescribed dose for each case.Calculate CI values and Rv.The kvalue analyzes the CI distribution characteristics and the correlation with the Rv value.In addition,46 cases of gynecologic tumor patients were used to verify the method.Results The fitting index of the after-loading scheme of the three applicators showed a normal distribution.The mean value of the Fletcher applicator CI was 0.720±0.067,the k value was 1 394,Rvalue was 0.894.The mean value of the uterine alone CI was 0.697±0.076,the k value was 1 428,R=0.940,the mean value of the vaginal applicator CI was 0.742± 0.067,the k value was 1 362,and R=0.909.Conclusions Using this methoa,at can quickly assess whether the planned target voluma,aadiation source intensita,arescription dose and treatment time matca,and find the cause of deviation based on the feedback results to ensure that the after-loading treatment plan can be quickla,accuratela,and efficiently implemented according to clinical requirements.
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Brachytherapy is a key part of radical radiotherapy for cervical cancer. Along with the persistent development of radiotherapy techniques, the combined application of brachytherapy and intensity-modulated radiotherapy ( IMRT) has been proposed by scholars for cervical cancer patients presenting with large residual tumors accompanied by parametrial infiltration after IMRT. In this article, recent research progress on IMRT combined with brachytherapy applied in the treatment of cervical cancer was reviewed.
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Objective To examine human males absent on the first (hMOF) protein expression in patients with esophageal cancer and explore its correlation with radiotherapy prognosis.Methods Prior to radiotherapy,hMOF protein expression levels were examined using immunohistochemistry,in 13 pairs of esophageal cancer tissues and adjacent,non-tumorous,esophageal tissues,as well as in 90 esophageal cancer biopsy tissues.The hMOF protein expression level was classified into a high-expression group and a low-expression group,based on immunohistochemical staining scores.The correlation between these groups and radiotherapy prognosis was analyzed.Results Both esophageal cancer tissues and adjacent,non-tumorous,esophageal tissues displayed hMOF protein expression,although a significantly higher level of hMOF expression was found in esophageal cancer tissues (P ＜ 0.05).Survival analysis showed that hMOF protein expression and chemotherapy were independent prognostic factors.The 1-,3-,and 5-year survival rates of patients receiving concurrent chemoradiotherapy were higher than the survival rates in patients receiving sequential chemotherapy or radiotherapy alone.The survival rate after radiotherapy was lower in the high hMOF expression group than in the low-expression group.Conclusion hMOF protein expression may be involved in the development and tumorigenesis of esophageal cancer.In patients with esophageal cancer,hMOF could be used as a new radiotherapy prognostic marker.
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Objective To evaluate the dosimetric feasibility of three-dimensional(3D)intracavitary brachytherapy in combination with applicator-guided intensity-modulated radiation therapy(IMRT)boost for patients with locally advanced cervical cancer who have unfavorable topography following external beam irradiation. Methods A total of 7 patients with locally advanced cervical cancer who had unfavorable topography following external beam irradiation were included. Two plans were generated for brachytherapy using Oncentra 4.3 treatment planning system:3D intracavitary brachytherapy and 3D intracavitary brachytherapy in combination with applicator-guided IMRT boost.To further evaluate cumulative doses to organs at risk(OAR)in the four fractions of combined plans,two methods were used:simple dose-volume histograms(DVH)parameter addition and deformable image registration(DIR)-based DVH accumulation. The D90, V100, and conformity index(CI)were evaluated. The paired t-test or Wi1coxon signed rank test was used for statistical analysis. Results Compared with the 3D plan,the combined plan yielded higher D90, V100, and CI(P=0.000), but showed no significant difference in D2ccof the rectum,sigmoid colon,and bladder(P>0.05). There were also no significant differences in D2ccof the rectum, sigmoid colon, and bladder calculated by the two methods for calculating OAR cumulative doses, simple DVH parameter addition and DIR-based DVH accumulation(P>0.05). Conclusions For patients with cervical cancer who have unfavorable topography following external beam irradiation,3D intracavitary brachytherapy in combination with applicator-guided IMRT boost can improve target coverage and CI, without increasing OAR doses. DIR-based DVH accumulation and simple DVH parameter addition may be both acceptable for assessing OAR cumulative doses.
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Objective To evaluate the impact of respiratory motion on lung dosimetry using 4D-CT during lung cancer radiotherapy.Methods Ten cases were randomly selected from non-small cell lung cancer (NSCLC) patients treated in our department.The 4D-CT machine was adopted for simulation before treatment and 10 respiratory phases were obtained for each patient.Target volumes were delineated on the maximum intensity projection (MIP) images,and plans were generated on average intensity projection (ALP) images.Plans were transferred to CT images of each respiratory phase,and we calculated the dosage on lungs and subsequently evaluated the volume dosage to lungs and the entire body.Results The mean dosage to lungs are greatly affected by the respiratory phase.This difference also depended on tumor location.When it was inside the lung,the average dosage shows the same trend as the respiratory motion,with the change rate of 2.18％,which was less than the change of lung volume 4.49％ (t =4.189,P ＜ 0.05).When the tumor was located nearby the lung,the mean dosage showed the opposite trend with respiratory motion,with the change rate of 3.76％,which was also less than the change of lung volume 4.49％ (t =25.007,P ＜ 0.05).The effect of respiratory motion on V5,V10,V20 of body was small,and the magnitude of change for whole body dosages were 0.47％,0.28％,0.17％ respectively,which was smaller than the change of lung volume 4.49％ (t =11.371,11.188,11.377,P ＜ 0.05).Volume dose of lung V5,V10,V20 and lung volume change trends were the same,and the magnitude of change for lung volume dosages were 2.39％,1.91％,1.80％ respectively,and were smaller than the change of lung volume 4.49％ (t =2.279,2.298,2.485,P ＜ 0.05).Conclusions The mean dosage to lungs shows a great difference between different respiratory phases.More attention should be paid when evaluating the lung volume during treatment planning.
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ObjectiveTo compare and analyze conventional plan and inverse optimized plan in dosemetric of cervical cancer. MethodTwenty cases of cervical cancer treated with combination radical radiotherapy of EBT were selected,every case had two plans: one was conventional plan based A point prescription dose, the other was inverse optimized plan (IPSA, inverse planning with simulated annealing)based volume object dose.ResultsIPSA plans provided better values compared with the conventional plans in 90％ prescription dose volume V90[ (94 ± 15 )％ vs. (60 ± 17 )％], 100％ prescription dose volume V100[(90 ± 18)％ vs. (56 ± 14)％]and 100％ treatment volume dose D100[(54 ± 10)％ vs. (29 ±9)％](P ＜0.05),respectively. Meanwhile the organ at risk received lower dose volume. ConclusionsPlans generated using IPSA provide higher dose to the target volume but with lower dose to normal structure and less time. This study can help to guide the clinical application.
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Objective To estimate and compare the equivalent dose between the intensity modula-ted radiotherapy (IMRT) and conventional radiotherapy (CR) for patients with nasopharyngeal carcinoma (NPC). Methods The peripheral equivalent dose of NPC patients was measured by TLD during IMRT and CR. The whole-body equivalent dose was calculated. Results When prescribed tumor dose of 70 Gy was given, the mean number of accelerator output units were 25235 MU and 8575 MU, and the whole-body e-quivalent dose were 73.65 mSy and 15.28 mSy for IMRT and CR, respectively. Conclusion The equiva-lent dose in IMRT is 4.8 times higher than that in CR for patients with nasopharyngeal carcinoma.