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Objectives To compare the dose distribution of the whole body γ-knife and three-dimensional conformal radiotherapy (3D-CRT) in the treatment of primary hepatic carcinoma to provide evidence for clinical treatment choice.Methods Totally 35 patients with primary hepatic carcinoma treated with whole body γ-knife from March 2014 to July 2015 underwent three-dimensional conformal radiotherapy planning,and dose volume histograms were used to evaluate the dose distribution of target volumes and normal tissue,and moreover conformity index (CI) and homogeneity index (HI) were analyzed.Results Between the two treatment plans,D98 and the mean dose Da of GTV were higher in whole body γ-knife plan than those in three-dimensional conformal radiotherapy plan.For PTV,the V95 of γ-knife and three-dimensional conformal radiotherapy were (95.05±0.02)％ and (90.00±0.03)％ (P=0.00) respectively.Target coverage of whole body γ-knife was better.For organ at risk,γ-knife showed better protection of normal tissue.Three-dimensional conformal radiotherapy showed better HI (GTV:0.11±0.15 vs 0.23±0.02,PTV:0.14±0.04 vs 0.21±0.03),while more normal liver tissue received excessive exposure.The whole body γ-knife increased dose of target volumes and decreased dose of normal tissue,while three-dimensional conformal radiotherapy showed better HI.Conclusion Compared with three-dimensional conformal radiotherapy,the whole body γ-knife shows advantage in dose distribution but HI of target volumes.For clinical using,appropriate treatment needs to be chosen according to the patients' actual situation.
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Stereotactic body radiation therapy had a history for over 20 years since it was applied in elinical treatment,with promising outcomes in early-stage non-small cell lung cancer (NSCLC) and lung metastases.Air Force General Hospital was one of the earliest institutes which had launched SBRT in China.Our self-developed γ-ray SBRT technology was used to treat early-stage NSCLC and lung metastases.The adverse effects and cost of γ-ray SBRT were less than those for foreign technology.In conclusion,it is suitable for our national situation and worth to be widely introduced.
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Objective To explore the radiation dose from body γ-knife treatment to the nontargeted region's sensitive organs before and after shielding.Methods 20 patients suffering tumors less than 5 cm were selected.Calibrated thermoluminescence dosimeters (TLD) were placed above the sensitive organs,such as lens,thyroid gland and sexual gland,to measure the radiation dose received before shielding.Different plans were prepared for the patients with lung and renicapsule tumors using calibrators of different size.Radiation dose was measured by the aid of water phantom.For selected lungtumor treatment plan,the radiation doses were measured at the same location on the water phantom shielded with and without 1,2 and 4 cm lead,respectively.Results The maximum doses were 1 023.3 mGy for lens,1 235.7 mGy for thyroid gland and 1 176.8 mGy for sexual glands after treatment,respectively,being higher on the left site than the right.The radiation doses to the sensitive organs were higher for the water phatom with more tartgted points,decreasing by 55％-91％ after being covered with 1,2 and 4 cm lead shieldings.There were significant differences in doses received before and after lead shielding (t =14.4,12.9,13.3,P ＜ 0.05).Conclusions In the course of body γ-knife treatment,the additional factors would increase the dose to the sensitive organs.Therefore,it is necessary to provide lead shielding protection to the teenagers and adults with fertility when they undergo body γ-knife treatment.Trial registration Chinese Clinical Trial Registry,ChiCTR-OOC-16008259.
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Objective To study the dose characteristics of Body γ Knife and Tomotherapy treatment plans for hepatocellular carcinoma,and compare their differences between organs at risk (OAR) dose and the range of low dose.Methods CT simulation images of twelve patients with hepatocellular carcinoma were selected,the target volume and OAR were drew by doctor.Body γ Knife and Tomotherapy treatment plans were optimized with their own planning station.The dosimetric characteristics were evaluated by dose volume histograms and were compared.To analyze the difference between the two techniques,the paired t-test was applied.Results The Dmax and Dmean of target with Body γ Knife were higher than Tomotherapy (P =0.002,0.000),but the conformal index of PTV of Tomotherapy was superior to the Body γ Knife (P =0.001).The Dmax of spinal cord and left kidney with Body γ Knife was lower than Tomotherapy (P =0.013,0.012),and it was also in the Dean of stomach and left kidney (P =0.010,0.023).In the volume dose comparison,the V40,V35,V30,V25 and V20 of normal tissue (all Body-PTV) and liver (all liver-GTV) with Body γ Knife were higher than Tomotherapy (P =0.001,0.001,0.001,0.007,0.029),but the V10 and V5 were lower (P =0.019,0.031),the Dmax of stomach,Dmean of right kidney and liver were no statistical difference (P =0.247,0.308,0.401).Conclusions Both treatment plans could meet the clinical dosimetric need,by the same prescription dose,Dmax and Dmean of target of Body γ Knife were higher than Tomotherapy.Tomotherapy had excellent dose-target conformal and could reduce the range of V25-V40 of OAR and normal tissue,but the range of V5-V10 was increased obviously.
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Objective To compare the single-shot fields irradiated by three focusing modes of γ-knife and explore the approaches for improving the quality of stereotactic radiosurgery.Methods GAFCHROMIC(R) EBT3 mode flushing-free film was used to measure the single-shot fields irradiated by multi-source static focusing modes,multi-source single-axis rotating focusing mode and single-source double-axis rotating focusing mode of γ-knife.Also the uniformity and penumbra of the single-shot fields were compared.Results The 2D dose distribution of the single-shot fields irradiated by three focusing modes of γ-knife was different.In the axis (x,y,z),the rang of penumbra axial length ratios of multisource static focusing modes,multi-source single-axis rotating focusing mode and single-source double-axis rotating focusing mode were 0.13-0.48,0.17-0.33 and 0.28-0.54,in the diagonal direction of the wings plane (NSD,PSD),were 0.31-0.39,0.38-0.43 and 0.54-0.72,respectively;the penumbra axial length ratio of single-source double-axis rotating focusing mode was bigger than in multi-source static focusing modes and multi-source single-axis rotating focusing mode.On the no-wings plane,the area ratios of 80％ dose curve enveloped and 50％ dose curve enveloped(A80％/A50％)were 0.40,0.47 and 0.19,on the wings plane,were 0.61,0.53 and 0.35,respectively.The field uniformity of multi-source static focusing modes and multi-source single-axis rotating focusing mode were superior to single-source doubleaxis rotating focusing mode.Conclusions Considering dose distribution of the single-shot fields,the multi-source static focusing modes devices and the multi-source single-axis rotating focusing mode devices should be preferred,when important tissues and organs are adjacent to the target areas.Compared with single-source double-axis rotating focusing mode,both multi-source static focusing modes and multi-source single-axis rotating focusing mode could make more target areas to be surrounded by high dose region.
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ObjectiveTo evaluate the effect and complication of whole γ-knife stereotactic radiotherapy on the non-small cell lung cancer and explore the value of γ-knife stereotactic radiotherapy in treatment of non - small cell lung cancer. Methods42 patients with non -small cell lung cancer:γ-knife radiotherapy patients ,4 ～ 8Gy once a day,five times a week,4 ～ 10times and 40 ～50Gy in total. ResultsThe overall response rate (CR + PR) in γ-knife was 71.4％. The1-,2-and 3-year survival rates were 95.5％, 59.5％, 33.3％. ConclusionCompared with conventional radiation,γ-knife stereotactic radiotherapy could achieve tumor dose escalation,and give the normal tissue better protection at the same time. It could improve the tumor control rate of non-small cell lung cancer,improve long survival rate,and so could reduce the radiation reaction.
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Objective To evaluate the efficacy and side effects of whole body γ/-knife in patients with limited pancreatic carcinoma. Methods 111 patients with limited pancreatic carcinoma treated with the Stereotactie Gamma Ray Whole-Body Therapeutic System (Whole Body T-knife) were retrospectively an-alyzed. Patients were supine, fixed with a stereotactic body frame and vacuum bag, and then simulated by low-speed computed tomography. GTV, CTV and PTV were defined on the contrast-enhanced CT scans. It was required that 50% isedose line covered 100% of PTV and 70% isedose line covered more than 80% of GTV. The prescription dose was defined as 50% isodose. All patients were treated 5 fractions per week. The fractionated dose was 3-4 Gy for pancreatic head carcinoma, and 4-5 Gy for pancreatic body/tail carcino-ma. Irradiation of 40-51 Gy and 60-70 Gy were delivered to PTV and GTV margins, respectively. Re-suits The complete response rate, partial response rate and overall response rate of the primary tumors were 29.7%, 42.3% and 72.1%, respectively. The follow-up rate was 95.5%. The number of patients fol-lowed-up at 1-,2- and 3-year was 105,89 and 60. The 1-, 2- and 3-year overall survival rates were 49.3%,24.5% and 18.1%. For patients with stage Ⅰ/Ⅱ disease,the number of patients followed-up at 1-,2-,3-,4-and 5-year was 55,44,29,16 and 11 ;The 1-, 2-, 3-,4- and 5-year overall survival rates were 68%,34%, 30%, 21% and 17%, respectively. For patients with stage Ⅲ disease,the number of patients fol-lowed-up at 1-,2- and 3-year was 50,45 and 31 ;The 1-, 2- and 3-year overall survival rates were 28%,14% and 4%, respectively (χ~2=16.67, P=0.000). The acute side effects including nausea, vomiting and diarrhea were 71.2% of RTOG grade 1 -2 and 3.6% of RTOG grade 3. No treatment delay occurred.Conclusions With fractionated dose of 3-5 Gy,5 fractions per week and 40-51 Gy as total dose to PTV,whole body γ-knife is safe and effective to treat limited pancreatic carcinoma. The local control and overall survival could be improved.