ABSTRACT
Objective To compare the performances of Monaco and Pinnacle treatment planning systems (TPS) for volumetric modulated arc therapy (VMAT) optimization regarding lung cancer.The TPS was compared in terms of dose distributions,treatment delivery parameters and quality control results.Methods For 20 patients,including 10 cases of left lung cancer and l0 cases of right lung cancer,two VMAT plans were generated for each case:one with Monaco 3.0 TPS and the other with Pinnacle 9.2 TPS.Two plans were compared among plan dosimetrie distribution.conformity index and homogeneity index of the targets,the average dose,maximum dose,minimum dose and interested dose volume histograms of organs at risk(OAR,and delivery time and MUs of the therapy plans,the accuracy of treatment plans dose verification.Results Monaco provided better PTV coverage than Pinnacle (t =5.927-12.034,P ＜ 0.05) except Dminof PTV.Monaco had a worse sparing effect on lung than Pinnacle (t =3.545-7.485,P ＜0.05) except V10of diseased side lung and V5of total lung.In addition,Monaco had a better sparing effect on heart(t =2.836-4.011,P ＜0.05).Monaco had fewer delivery time(t =9.780,P ＜0.05)and MUs(t =5.304,P ＜0.05)of the therapy plans,and the pass rate of QA was better than Pinnacle(t =4.937,P ＜ 0.05).Conclusions For lung cancer patients,VMAT treatment plans obtained with Monaco and Pinnacle could offer clinically acceptable dose distributions.Pinnacle might have a better sparing effect on lung and fewer delivery time and MUs of the therapy plans.Monaco had a better PTV coverage and heart sparing.Moreover,Monaco had better accuracy of treatment plans dose verification.
ABSTRACT
Objective To explore the effect of horizontal beam on IMRT plan for lung cancer.Methods Totally 18 patients were enrolled,including 10 cases of left lung cancer and 8 cases of right lung cancer.Two intensity modulated radiation therapy (IMRT) plans were generated:one was the normal IMRT plan and another was the IMRT plan including a horizontal beam (H-IMRT).MUs,sub-field and the dose distribution of target and organs at risk (OARs) were compared.Results There were no statistically significant differences between two plans in D Dminand D of PTV,the V30 and D of the ipsilateral lung,V20 and V30 of the contralateral lung,and V30 of the total lung.When the horizontal beam was added,the PTV heterogeneity index (HI) and conformity index (CI) were significantly increased (t=-9.33,10.88,P＜0.05),the other dose index in lung was inferior (t =-1.55--7.58,P＜ 0.05),whleheart sparing were clearly better (t =1.84-3.99,P＜0.05),the number of MUs and segments were less(t =12.57,3.19,P ＜ 0.05).Conclusions IMRT in the treatment of lung cancer can further improve the PTV coverage when the horizontal beam is added.However,the increasing lung volume of low dose irradiation is not conducive to lung protection.
ABSTRACT
Objective To compare the dosimetric parameters of volumetric modulated arc therapy(VMAT),fixed field intensity modulated radiation therapy(IMRT)and three-dimensional conformal radiotherapy(3D-CRT)in the radiotherapy for the patients with locally recurrent nasopharyngeal carcinoma, and to analyze their characteristics. Methods Twelve patients with locally recurrent nasopharyngeal carcinoma were treated with VMAT, IMRT and 3D-CRT plan designed by Pinnacle 9.2 and Preciseplan 2.03 treatment planning system.The dosimetric parameters of targeted volumes and organs at risk were compared between three groups. Results The conformation indexes (CI)of VMAT and IMRT plans were similar,and they were both better than 3D-CRT plan,the difference was significant(P0.05).The monitor units(MU)and beam time in 3D-CRT group were better than those in other two groups,and VMRT group was better than IMRT group,the statistical differences were observed between three groups (P0.05).The doses of the spinal cord,optic nerve,optic chiasm and temporal lobe of brain in VMAT and IMRT groups were better than those in 3D-CRT group,there were statistical differences between them(P0.05).Conclusion There are differences of the targeted dose distribution between the three kinds of radiation technology, while VMAT and IMRT plans can cover the targeted areas and reduce the received doses of organs at risk.The CI,MU and beam time of VMAT plan are better than those of IMRT plan. 3D-CRT plan only has advantage in the MU and beam time.
ABSTRACT
Objective To explore the influence of the number and orientation of the beams on the optimization of IMRT plan.Methods Four IMRT plans were designed for 9 patients with cervical cancer,and 7 and 15 fields were applied.The 15-field plans had 30 segments and the 7-field plans had 55 segments.The initial beam angle degrees were 0° and 180°,respectively.Dose delivery time,MUs of plans,the dose distributions of the targets,organs at risk and normal tissues were analyzed and compared in the plans.Results Compared the plans with different beam directions under the same amount,no difference of the irradiation dosimetry in the target and organs at risk was found,except for irradiation dosimetry received by the 7-field 180° small intestine was about 4％ higher than the other three plans(F=6.164,P＜0.05).The terms of the volume of organs at risk got high dose irradiation(V40 and V30 of the rectum and bladder,V40 of the small intestine),which was similar in the 7-and 15-field plans.V20 and Dmean of organs at risk were significantly smaller(F=3.665-10.503,P＜0.05)in the 15-field plans.The 15-field plans needed a little longer treatment time(F=0.312,P＜0.05)and HI was slightly worse (F=12.933,P＜0.05),but the number of MUs was significantly reduced(F=4.650,P＜0.05).Conclusions Increasing the beam number will offset the negative impact of sub field reduction and get the similar dose distribution result.
ABSTRACT
Objective To investigate the strategy and announcements of surgery in primary retroperitoneal. tumor for improving the rescetable rate and decreasing the surgical risk.Methods Clinical data of 50 cases undergoing surgery of retroperitoneal tumor in our hospital from January 2004 to December 2008 were retrospectively analyzed.Results Tumors were benign in 20 cases and malignant in 30 cages.Complete resection was achieved in 39 cases(78%).in which combined organ resection carried out in 10 cases(20%),3 cases(6%)underwent partial resection.non-resection and had biopsy only were performed in 8 cases(16%),so the rescetable rate of this clinical weTe 84%(42/50).Conclusions Abundant preoperative preparation,wide open operation field and distinct anatomical dissection were the essential condition of the resecting primary retroperitoneal tumor.The relevant surgical skill should decrease the surgical risk.The tumor should be completely reaeeted in principle,and invaded neighboring organs should be resected with the discretion at the gane time.Completely resected was the key 10 improving the surviral rate and the strategy to decreasing the reeurence rate for recurrent retroperitoneal tumor.