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Objective To analyze the exposed dose of hippocampus(HC)of T3,T4nasopharyngeal carcinoma patients treated with intensity modulated radiotherapy(IMRT). Methods The bilateral HCs were delineated and were divided into head(HH),body(HB)and tail(HT)for 62 nasopharyngeal carcinoma patients treated with IMRT.The dose parameters of HC were then analyzed. Results The mean dose of left and right HC was(1 127±704)cGy,(1 173±762)cGy. The mean dose of left HH,HB and HT was(1 732±1029)cGy,(820±632)cGy,(423±366)cGy(P=0.000);while the mean dose of right HH, HB and HT was(1 985±1101)cGy,(837±531)cGy,(432±343)cGy(P=0.000).The exposed dose and the volume exposed in different dose of HH were obviously higher than those of HB and HT.The dose parameters of HH,HB and HT decreased in turn. The involvement of sphenoid sinus,ethmoid sinus and cavernous sinus correlated with high exposed dose of HC. Conclusions The exposed dose of HH,HB and HT was different in nasopharyngeal carcinoma patients treated with IMRT.The exposed dose of HH was the highest,which should be emphasized especially. The involvement of sphenoid sinus,ethmoid sinus and cavernous sinus suggest high exposed dose of HC.
ABSTRACT
Objective To analyze the radiation doses to the head, body, and tail of the hippocampus in intensity-modulated radiotherapy(IMRT)for nasopharyngeal carcinoma(NPC). Methods Ten NPC patients treated with IMRT were selected,and the head, body, and tail of both hippocampi were delineated on T1-weighted images. The doses to the hippocampus were then analyzed. WAIS-CR speech test results were tested by paired sample t-test. Results The mean doses to left and right hippocampi were 1 147±976 cGy and 1 011±602 cGy, respectively. The mean doses to the head, body, and tail of the left hippocampus were 1 739± 1 317 cGy, 890± 982 cGy, and 547± 688 cGy, respectively(P=0.042);the mean doses to the head,body,and tail of the right hippocampus were 1 691±942 cGy,744±483 cGy,and 531±603 cGy,respectively(P=0.002).The dose to the hippocampus decreased from the head to the tail, and the irradiated volume also decreased as the dose varied. Conclusions The dose to hippocampus decreases from the head to the tail in NPC patients treated with IMRT,which is worthy of attention.
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ObjectiveTo evaluate the local failure and the impact on survival by prospectively comparing involved field radiotherapy (IFRT) and elective nodal irradiation (ENI) in combination with concurrent chemotherapy for locally advanced non-small cell lung cancer ( LA-NSCLC ).Methods LANSCLC patients were treated with 2 cycles of carboplatin ( AUC =5 - 6,d1 ) combined with paclitaxel ( 175mg/m2 ),followed assessment without distant metastasis,then randomized into IFRT (45 patients) or ENI (54 patients) arm.IFRT included primary tumor,ipsilateral hilar and positive mediastinal lymph nodes;ENI included the primary lesion,ipsilateral hilar,hilateral mediastinal lymph node drainage and bilateral supraclavicular area.The prescription dose was given as high as possible with V20 ≤35％ and spinal cord dose ≤50 Gy,combined weekly paclitaxel 40 mg/m2 concurrent chemotherapy.The Kaplan-Meier method was used to estimate survival data and the log-rank method was used to test distribution of survival time between arms.ResultsThe follow-up rate was 99％.49,29 and 17 patients were followed-up for 1-,2-and 3-year,respectively.More patients from group IFRT received ＞60 Gy than ENI (49％ vs.26％,x2 =5.59,P =0.018 ).The local failure rates were 29％ and 36％,respectively ( x2 =0.46,P =0.497 ).The 1-,2-and 3-year local tumor progression-free survival rates were 76％,69％,65％ and 80％,53％,49％ ( x2 =0.74,P =0.389),respectively; the 1-,3-and 5-year overall survival rates were 80％,41％,33％ and 69％,32％,13％ (x2 =3.97,P =0.046),respectively.There were no significant differences in acute and late toxicities between the arms ( x2 =3.910 - 0.155,P =0.142 - 0.925 ).ConclusionsIFRT improved radiation dose and survival rate and did not increase the failure of elective lymph node region compared with ENI.The toxicities were no differences between IFRT and ENL Further investigation with big size sample is warranted.
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Objective To evaluate the respiratory movement of the both lungs with four-dimensional CT(4DCT), and determine the optimal respiratory phase series CT images for radiation dose calculation. Methods From November 2005 to November 2006,thirty patients with lung cancer who received 4DCT scan were enrolled,including 15 left and 15 right lung cancer cases,25 men and 5 women. The media age was 55 (35-78) years old. After 4DCT scanning, the image was treated with Advantage 4D workstation,and then transmitted into Pinnacle station( Adac 7.4). The both lungs were automatically outlined using Pinnacle station with CT recognition value of-900 to-200 Hu. Then-the same physician examined the unreasonable parts and revised them. After the delineation was completed,the volume of 10 respiratory phases of lung was obtained. Results The average respiratory phase in inspiratory and expiratory phases was 78.87%±2.71% and 26.32%±3.17% in the tumor located lung,77.55%±2.81% and 24.73%±2.55% in the healthy lung. The maximum and minimum mean volume was 106.48%±3.00% and 94.23%±2.78% in the tumor located lung,107.47%±2.43% and 93.65%±2.32% in the healthy lung. The volume at the end of inspiratory and expiratory was 106.43%±3.07% and 94.63%±2.71% in the tumor located lung, 107.37%±4.62% and 93.98%±2.34% in the healthy lung. Conclusions The series CT images scan on 20% ,30% and 80% respiratory phases are reasonable for radiation dose calculation. The maximum and minimum average lung volumes are almost equal to those at the end of inspiratory and expiratory.