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Background: Conformal Radiotherapy techniques adapting to the ballistics of delineated volumes allowed significant reduction in excess radiation induced mortality however the increasing number of long-term survivors and expanding use of cardiotoxic drug highlight the persistent need for maximal cardiac possible sparing. The low dose volume of left ventricle are better predictor of acute coronary events than mean heart dose. Materials and Methods: 38 post-MRM patients were randomized to treatment by 3Dimensional Conformal Radiotherapy (3D CRT) and Intensity Modulated Radiotherapy (IMRT) technique. Two tangential beams were used in 3D CRT technique while five to seven (mostly tangential beams) were used in inversely planned IMRT technique. The dose volume parameters of planning target volume, heart and left ventricle were compared. Results: The dosimetry of Planning target volume showed significantly better coverage in IMRT technique (D90, D95) however the D50 was comparable in both the techniques. In dosimetry of heart, the high dose volumes (V30, V40) were nearly comparable in both the techniques. The other dose volume parameters (V5, V10, V20, V25, D33, D67, D100) and the mean dose were significantly lesser in 3D CRT technique along with significantly better sparing of left ventricle (Dmean and V5). Conclusion: The dosimetry of target volume was better with IMRT technique, but this was accompanied by a huge increase in dose to whole heart and specifically the left ventricle which has strong potential to translate into an increased cardiotoxicity. A better distribution of the target region may be obtained by multiple segmentation of the two tangential fields in 3D CRT plans with further reduction in dose to heart and left ventricle.
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Objective To investigate the efficacy and side effect of induction chemotherapy plus concurrent chemoradiotherapy ( IMRT) in the treatment of 81 patients with locally advanced nasopharyngeal carcinoma ( NPC) . Methods 81 patients with locally advanced NPC were divided into the vinorelbine group and fluorouracil group . Patients in the vinorelbine group were given vinorelbine 25-30mg/m2 d1,d8,DDP 75mg/m2 ,d1-d3.Patients in the fluorouracil group were given DDP 75mg/m2,d1-d3,fluorouracil 750 mg/m2 d1-d5.The treatment schedules were recycled every 3 weeks.After 2-4 cycles, the patients received concurrent chemoradiotherapy .In the vinorelbine group,IMRT with NVB 25-30mg/m2,DDP 40mg d1,d8,d22,d29,d43,d51 from the first day of IMRT.In the fluorou-racil group,IMRT with fluorouracil 750mg/m2 ,DDP 25/m2 d1,d8,d22,d29,d43,d51 from the first day of IMRT. Results The overall leukopenia and thrombocytopenia decline was 47.5% vs 24.4% in patients with Ⅲ and Ⅳgrade(χ2 =4.73,P<0.05).5-year locoregional relapse-free survival rates were 85.0% vs 65.9%(χ2 =4.05,P<0.05).5-year overall survival rates were 85.0%vs 68.3%(χ2 =3.18,P<0.05).Conclusion NP regiment induc-tion chemotherapy plus concurrent chemoradiotherapy for advanced NPC can achieve better result in clinical response and 5-year locoregional relapse-free survival rate compared with FP and the effect is clinically acceptable .
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Objective To observe the clinical efficacy and adverse reactions of intensity modulated radiotherapy (IMRT) combined with cisplatin for patients with carcinoma of cervix.Methods One hundred patients with carcinoma of cervix were randomly divided into 2 equal groups to undergo IMRT only (IMRT group)and IMRT combined group (IMRT with cisplatin chemotherapy group),with 50 cases in each.Both groups were treated with external intensity modulated radiotherapy,with the total dose of 50 Gy,2 Gy/fraetion,25 fractions in total,and 5 times/week.Two weeks later,internal radiotherapy followed,with the total dose of 42-48 Gy,1 time/week with 6-8 times and 6-7 Gy/fraction.When the internal radiotherapy began,the external radiotherapy stopped immediately.The combination group was treated concurrently with cisplatin given by intravenous drip once a week,at the dose of 30-40 mg/m2 body surface area for 4-5 weeks,and with total cisplatin dosage of 50-65 mg.Follow-up was conducted for 18 months(3-60 months).The 1-,3-,and 5-year survival rates,local control rate,distant metastasis rate,and disease-free survival rate,blood test,rectum,and bladder were observed.Results The 1-year survival rate,local control rate,distant metastasis rate,and disease-free survival rate did not differ significantly between these 2 groups,however,the 3-and 5-year survival rates,local control rates,distant metastasis rates and disease-free survival rates of the combination group were all significantly better than those of the IMRT group (x2 =3.843,4.336,4.336,4.960,P ＜ 0.05 ; x2 =3.934,4.454,4.000,4.244,P ＜0.05).The incidence rates of radiation proctitis and leukopenia of the combination group were significantly higher than those of the IMRT only group (x2 =4.110,4.320,P ＜ 0.05),whereas the incidence rates of cystitis,anemia,and thrombocytopenia were not significantly different between these 2 groups.No serious grade 3-4 proctitis and cystitis were observed in these 2 groups.Conclusions The IMRT combined with cisplatin chemotherapy shows higher 3-year and 5-year long-term efficacy in the patients with carcinoma of cervix than IMRT only group.
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Objective: To discuss the methods and items for clinical linear accelerator (Clinac) and 3D treatment planning system (TPS)/intensity modulated radiotherapy(IMRT) system based on 2D ionization chambers array(2D-ICA). Methods: The 2D-I-CA laid on the anthropomorphic phantom with five centimeters and which was put on another five centimeters same phantom.All data have gained as following conditions: the SAD is 100 cm and the SSD is 90 cm; the fields' size are 2 cm, 5 cm, 10 cm,15 cm ,20 cm respectively and 2 cm×10 cm ,5 cm×20 cm ,20 cm×5 cm, MU=100 cGy;the Clinae and TPS were verified by some special items for checking their dose accuracy, such as, square fields, rectangular fields, and rectangular fields with 600 wedge or 300 wedge, which were measured for verification their flatness and symmetry. And some measured items were only for checking multileaf collimator (MLC) and TPS calculated accuracy. So, we developed moveable MLC fields and IMRT plans and compound fields to evaluate leafs side effects and leafs end effects and transmission effects. Results: The flatness value of square and rectangular fields was 100.07%～102.66%,and their symmetry value was 0.10%～1.49%; and these irradiate fields' size were compared with light fields' sizes, which the X direction deviation was-1.5%～0.7% ,the Y direction deviation was-1.4%～1.0%,and their average value was-0.47%.To verify calculated data for TPS ,we developed Gamma value and ab-solute value (<4%)to evaluate their accuracy. For square and rect-angular fields, The Gamma value was 92.02%～96.35%.In com-pound fields Which were composed with two half fields (X1 = 5 cm, X2 =0 cm, Y= 10 cm and X1 = 0 cm,X2 = 5 cm, Y=10 cm),the maximum deviation was about 5%.And five fields (2 cm×10 cm) composed one fields (10 cm×10 cm),the maximum deviation was about 10% in the joint place. The Gamma value of one fields was 96.6%, another was 93.2% in the moveable fields. Conclusions: To dollop 2D ionization chambers array to verify the dose for Clinac and TPS, it was so quick and simple, and it was important that it bring more accurate dose evaluation and more clinical quality assurance and quality control methods.