Changes of volume and dose in target volume and organ at risk for nasopharyngeal carcinoma during intensity modulated radiotherapy / 国际肿瘤学杂志

At present,intensity modulated radiation therapy has been the main treatment of nasopharyngeal carcinoma.In the course of 6-7 weeks,most physicians use the initial formulation of the radiotherapy plan.Studies have indicated that the reduction of primary tumor and lymph nodes,as well as the reduction of normal tissue and body surface profile due to the weight loss,will affect the dose distribution of the target and the organs at risk,so as to influence the therapeutic effect of some patients.Therefore,it is necessary to reset and modify the target volumes during the radiotherapy for nasopharyngeal carcinoma.

The change of target area and the surrounding structure during the intensity modulated radiotherapy of nasopharyngeal carcinoma / 国际肿瘤学杂志

Intensity modulated radiation therapy(IMRT)has become the mainstay of treatment modal-ity for nasopharyngeal carcinoma(NPC). The whole treatment course generally continues 7 to 8 weeks. With the radiotherapy proceeding,the patients exhibit oropharyngeal reaction aggravating,weight losing and tumor shrinking,resulting in the changes of tumor target and surrounding tissue. Those changes may influence the dose distribution of tumor and organ at risk. It is necessary to modulate target volume during radiotherapy of NPC.

Feasibility, efficacy and cosmetic effect of three-dimensional conformal external beam partial breast irradiation for the selected early stage breast cancer patients after breast-conserving surgery / 中华放射肿瘤学杂志

ObjectiveTo explore the feasibility,efficacy and cosmetic effect of three-dimensional conformal external beam partial breast irradiation (EB-PBI) after breast-conserving surgery for the selected Chinese early stage breast cancer patients.MethodsFrom June 2003 to December 2010,Forty-four early stage breast cancer patients underwent EB-PBI after breast-conserving surgery.Twenty patients had CT simulation scan in moderate deep inspiration breathing hold,and twenty-four patients in free breathing.EB-PBI was planned and delivered by three-dimensional conformal radiotherapy (3DCRT)with four noncoplanar beams.The prescribed dose was 3.40 Gy per fraction in thirty-nine patients and 3.85 Gy per fraction in five patients,twice per day at an interval of at least six hours,in five consecutive days.Results The number of patients with follow up time of 2,3 and 5 years were 39,31 and 16.Grade 1 acute radiationinduced dermatitis was observed in 17 patients (39％) at three months.Cosmesis was good or excellent in all cases at six months after radiotherapy and in 95％ cases at two years after radiotherapy.The 2-,3-and 5-year local control rates were 100％,99％ and 94％,respectively.The 2-,3-,and 5-year survival rates were all 100％ and no metastases occurred.Conclusions EB-PBI delivered by 3DCRT is feasible for selected Chinese early stage breast cancer patients after breast-conserving surgery.The cosmetic effect,local control rate and long-term survival rate are satisfactory,and acute radiation toxicity is very low.

Comparison of displacement of the geometry constituted by silver clips in cavity in the different state of respiration assisted by active breathing control system in external-beam partial breast irradiation / 中华放射肿瘤学杂志

ObjectiveTo investigate the effect of the displacement of the selected silver clip in the different respiratory state achieved by active breathing control ( ABC ) system on the displacement of the geometry constituted by all of the silver clips at the border of the cavity in external-beam partial breast irradiation (EB-PBI).MethodsTwo sets of CT images in state of moderate deep inspiratory breathing hold (mDIBH),deep expiratory breathing hold (DEBH),and free breath (FB) were acquired in the same CT simulation assisted by ABC system for each of the 27 patients after breast conservative surgery.All silver clips in the cavity were delineated based on each set of CT images.Thereafter,the irregular geometry based on the silver clips as the vertices was automatically formed.Four selected clips located at the top,bottom,lateral border and medial border of the cavity were correspondingly manually registered based on automatic registration of the CT images acquired in the same or different state of respiration including mDIBH,FB,and DEBH.The displacement of center of the geometry in the direction of right-left (RL),anterior-posterior (AP),and superior-inferior (SI) separately based on automatic registration and manual registration was evaluated.The difference of the displacement was analyzed by Kruskal-Wallis H-test and Kolmogorov-Smirnov Z-test.Results When registered between mDIBH and mDIBH,FB and FB,DEBH and DEBH,the differences of the displacement of the center of geometry were not statistically significant (H =0.00 - 1.76,P=0.184-0.954). When registered between mDIBH and DEBH,the differences were statistically significant ( Z =11.31 - 23.00,P =0.000 - 0.001 ).There were statistically significant differences in the displacement of geometry center based on the selected silver clip between different registration forms in AP and SI directions (Z=4.76-25.54,P=0.000-0.029).ConclusionsThe difference of intrafraction displacement of the geometry constituted by the clips between the same respiratory states in the three dimensional direction is not statistically significant,but the difference is statistically significant between the different respiratory states in AP and SI directions.

Measurement of Intra-Fraction Displacement of the Mediastinal Metastatic Lymph Nodes Using Four-Dimensional CT in Non-Small Cell Lung Cancer

OBJECTIVE: To measure the intra-fraction displacements of the mediastinal metastatic lymph nodes by using four-dimensional CT (4D-CT) in non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: Twenty-four patients with NSCLC, who were to be treated by using three dimensional conformal radiation therapy (3D-CRT), underwent a 4D-CT simulation during free breathing. The mediastinal metastatic lymph nodes were delineated on the CT images of 10 phases of the breath cycle. The lymph nodes were grouped as the upper, middle and lower mediastinal groups depending on the mediastinal regions. The displacements of the center of the lymph node in the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions were measured. RESULTS: The mean displacements of the center of the mediastinal lymph node in the LR, AP, and SI directions were 2.24 mm, 1.87 mm, and 3.28 mm, respectively. There were statistically significant differences between the displacements in the SI and LR, and the SI and AP directions (p < 0.05). For the middle and lower mediastinal lymph nodes, the displacement difference between the AP and SI was statistically significant (p = 0.005; p = 0.015), while there was no significant difference between the LR and AP directions (p < 0.05). CONCLUSION: The metastatic mediastinal lymph node movements are different in the LR, AP, and SI directions in patients with NSCLC, particularly for the middle and lower mediastinal lymph nodes. The spatial non-uniform margins should be considered for the metastatic mediastinal lymph nodes in involved-field radiotherapy.

Comparison of the patient-specific internal gross tumor volume for primary esophageal cancer based separately on three-dimensional and four-dimensional CT simulation images / 中华放射肿瘤学杂志

Objective To compare the position,volume and matching index (MI) of patientspecific internal gross tumor volume (IGTV)delineated by 4 different approaches based on three- dimensional and four - dimensional CT ( 3 DCT and 4 DCT ) image for primary esophageal cancers.Methods Thirteen patients with primary esophageal cancer underwent 3DCT and 4DCT simulation scans during free breathing,and the patient were divided into group A (tumor located in the proximal thoracic esophagus) and B (tumor located in the mid-and distal thoracic esophagus).IGTV were delineated using four approaches: The gross tumor volume (GTV) contours from 10 respiratory phases were combined into IGTV10 ;IGTV2 was acquired by combining the GTV from 0％ and 50％ phases; IGTVMIP was the GTV contour delineated from the maximum intensity projection (MIP) ;IGTV3D was acquired from the enlargement of 3 DCT-based GTV by each spatial direction on the motion amplitude measured in the 4DCT.ResultsTarget movement in lateral (LR),anterio-posterior (AP),superio-inferior (SI) directions showed no statistically significant difference (0.11 cm,0.09 cm,0.18 cm,respectively; χ2 =1.06,P=0.589),and there was no statistically significant difference in centroid positions between IGTV10 and IGTV2 or IGTV3D in group A (t =-2.24,-0.00,P =0.089,- 1.000 ),MI between IGTV10 and IGTV2,IGTV10 and IGTV3D were 0.88,0.54,respectively. For group B, target movement amplitude in SI direction was bigger than in LR, AP ( 0.47 cm,0. 15cm,0. 12 cm,X2= 12.00,P = 0.002).Therewasno significantdifference betweenIGTV10 andIGTV3D inLR, AP, SI ( t =- 0.80.- 0.82,- 1.16,P = 0.450.0.438.0.285 ), MI was 0.59 ; but the target center coordinates was demonstrated significant difference in SI between IGTV10 and ICTV2 for group B ( t = 2.97.P = 0.021 ), Mlwas 0.86.Thevolume of IGTVMIPwassmaller thanIGTV10 ( t =- 2.84,P = 0.025 ), but the position of IGTv10 and ICTVMIp were with no statistically significant difference in the LR,AP,SI ( t =- 0.25,0. 84. - 1.22,P = 0. 809,0.429.0.263 ) ,MIbetweenIGTV10andIGTVMIp was 0.78.Conclusions Patient-specific IGTV can be acquired from 4DCT with correct target coverage while avoiding a geographic miss for the thoracic esophageal cancer,but IGTV2 and IGTVMIP can not contain all the information about primary tumor position,shape.and size at different phases of the respiratory cycle.

Analysis of GTV artifacts in each phase of four dimensional CT for peripheral lung cancer based on three dimensional CT assisted with active breathing control / 中华放射肿瘤学杂志

Objective To analyze artifacts of gross tumor volume (GTV) and correlated factors in each phase images of four dimensional CT (4DCT) for peripheral lung cancer based on three dimensional CT (3DCT) assisted with active breathing control.Methods Nineteen patients with peripheral lung cancer underwent 3DCT (CTFB) and 4DCT simulation scans during free breathing and then underwent 3DCT simulation scans in end inspiration hold (CTEIH) and end expiration hold (CTEEH) assisted with active breathing control.The relative deviations (Devref) between the reference GTV (GTVref) and the GTVsdelineated based on CTFB (GTVFB) and all phases of 4DCT were calculated respectively.Correlations between GTVref and Devmax and between the tumor motion in the cranio-caudal (CC) direction and Devref were analyzed.Results The maximum median Devref of GTV was GTVFB with 17.83％,and the maximum median Devref of the GTV in all phases of 4DCT was GTV30 with 17.20％.A significant negative correlation was found between GTVEIH and Devmax (r =-0.691,P =0.001).The Devref was crrnelated with the tumor motion amplitude in the CC direction (r =0.323-0.617,P =0.005-0.150).The partial regression coefficient of influence of GTVref size and motion amplitude in the CC direction to the tumor Devmax were -0.500 and 0.583,P =0.002 and 0.001,respectively.Conclusions The GTV artifacts in different phase of 4DCT for the peripheral lung cancer were different to each other,and the influence of target displacement to artifacts was larger than that of target volume,so artifacts could be reduced by controlling breathing to reduce target displacement.

A correlation study on position and volume variation of primary lung cancer during respiration by four-dimensional CT / 中华放射肿瘤学杂志

Objective To investigate the correlation of position movement of primary tumor with interested organs and skin markers,and to investigate the correlation of volume variation of primary tumors and lungs during different respiration phases for patients with lung cancer at free breath condition scanned by four-dimensional CT (4DCT) simulation.Methods 16 patients with lung cancer were scanned at free breath condition by simulation 4DCT which connected to a respiration-monitoring system.A coordinate system was created based on image of T5 phase,gross tumor volume (GTV) and normal tissue structures of 10 phases were contoured.The three dimensional position variation of them were measured and their correlation were analyzed,and the same for the volume variation of GTV and lungs of 10 respiratory phases.Results Movement range of lung cancer in different lobe differed extinct:0.8 - 5.0 mm in upper lobe,5.7 -5.9 mm in middle lobe and 10.2 - 13.7 mm in lower lobe,respectively.Movement range of lung cancer in three dimensional direction was different:z-axis 4.3 mm ± 4.3 mm＞ y-axis 2.2 mm ± 1.0 mm ＞ x-axis 1.7 mm ± 1.5 mm ( x2 =16.22,P =0.000),respectively.There was no statistical significant correlation for movement vector of GTV and interested structures (r =-0.50 - -0.01,P =0.058 - -0.961 ),nor for volume variation of tumor and lung ( r =0.23,P =0.520 ).Conclusions Based on 4DCT,statistically significant differences of GTV centroid movement are observed at different pulmonary lobes and in three dimensional directions.So individual 4DCT measurement is necessary for definition of internal target volume margin for lung cancer.

Comparative study of treatment planning between intensity - modulated arc therapy and simultaneously integrated boost intensity-modulated radiotherapy in nasopharyngeal carcinoma / 中华放射肿瘤学杂志

Objective To compare the dosimetric differences of target volume and organ at risk between intensity-modulated arc therapy (IMAT) and simultaneously integrated boost intensity-modulated radiotherapy (SIB-IMRT) in nasopharyngeal carcinoma. Methods IMAT and SIB-IMRT treatment plans of 10 nasopharyngeal carcinoma cases were generated by Varian Eclipse ver8. 6 treatment planning system. The dosimetric parameters of target volume and organ at risk (OAR), the monitor units (MU) and treatment time were compared between IMAT and SIB-IMRT treatment plan. Results The conformal index ( CI ) of PTV, PTV1, PTV2 of IMAT and SIB-IMRT were 0. 71 and 0. 75 ( Z = - 2. 32, P ＜ 0. 05 ), 0. 54 and 0. 59 (Z= -2.56,P＜0.05), 0.71 and 0.78(Z= -2.52,P＜0.05), respectively. the homogenous index (HI) of PTV, PTV1, PTV2 of IMAT and SIB-IMRT were 10.5 and 11.2(Z= -0. 84,P＞0.05),13. 1 and 17. 1(Z= -1.68,P＞0.05) and 14. 1 and 13.3(Z= -1. 01,P＞0.05) respectively;the brain-stem mean does were 3512. 8 cGy ± 406. 2 cGy and 3384. 3 cGy ± 361.3 cGy ( Z= - 1.82, P ＞ 0. 05 ); the brain-stem maximum dose were 5528. 1cGy ± 192. 9 cGy and 5727. 5 cGy ± 356. 3 cGy ( Z = - 1.12, P ＞ 0. 05 ); the maximum dose of spinal-cord were were 4186. 1cGy ± 88.7 cGy and 4390. 2 cGy ± 74. 9 cGy ( Z =-2. 38 ,P ＜ 0. 05 ). There were no significant differences between parotid dose and normal tissue ( P ＞0. 05. ) MU were 606 ± 96 and 1308 ± 213 for IMAT and SIB-IMRT ( Z= - 2. 52, P ＜ 0. 05 ). Conclusions The IMAT plan showed a better conformal index than SIB-IMRT plan, with the same dosimetric parameters of the target volume and OAR. The IMAT plan could reduce normal tissues dose, monitor units and treatment time in the treatment of nasopharyngeal carcinoma.

Comparative study of the displacement of the selected clips in the cavity measured by orthogonal kilovoltage X-ray film in conditions of free breath and active breathing control for patients treated by external-beam partial breast irradiation / 中华放射肿瘤学杂志

Objective To compare the displacements of the clips in the cavity measured with orthagonal kilovoltage (KV) X-my plain film in conditions of moderate deep inspiration breathing hold(mDIBH) and free breath (FB), and compare the margins from clinical target volume (CTV) to planning target volume (PTV) based on the displacements. Methods Before radiotherapy, 2 and 5 sets of orthogonal KV plain film were respectively collected in mDIBH and FB group, then the automatic registration of the reconstructed KV plain film and DRR derived from the planning OF images was finished. In conditions of mDIBH and FB, the displacements of the selected clip at the same location in the different directions and of the different selected clips in the same direction were compared. The margins in three dimensional directions were calculated and compared in conditions of mDIBH and FB . Results In FB hold group, the difference of displacement in left-right (LR), cranial-caudal (CC) and anterior-posterior (AP) directions were statistically significant between the clips at the cranial and caudal border of the cavity (9. 7 mm and 10. 6 nun (Z = -2. 12,P =0. 037) ,7. 3 mm and 8. 3 mm (Z = -2. 31 ,P=0. 041) ,15.5 mm and 16. 1 nun (Z = -2. 32,P = 0. 041)), but not statistically significant for the clips at the bottom and lateral P=0.814),15.7 mm and 16.5 mm (Z=-0.26,P=0.856)). The corresponding differences in the different directions were statistically significant (5.0 mm and 7. 8 mm(Z = -2. 31, P =0. 036), 5.0 mm and 9. 3 nun (Z= -2. 21,P=0. 021),7. 8 mm and9.3 mm (Z= -2. 11,P=0.041)). In FB group, the differences of the displacements of the four selected clips were statistically significant in CC and AP directions (7.3 mm and 8.4 mm (Z= -2.45,P=0.021), 15.5 mm and 16.5 mm (Z= -2.41,P= 0.043)), but not in LF direction (10.6 nun and 10.6 mm (Z= -0.24,P=0. 815)). In mDIBH group, the displacements in LF direction were statistically significant (4. 4 mm and 5.4 mm (Z = -2. 31, P = O. 031)), but not in CC and AP directions (8. 6 mm and 8.6 mm (Z =-0. 21, P = 0. 815), 10. 5 mm and 10. 8 mm (Z = -0. 27 ,P =0. 754)). There were statistically significant difference of the margins in LF and AP directions (9.7 mm and 5.0 mm (Z= -2.34,P=0.029),15.5 mm and 9.3 mm (Z= -2. 31,P= 0.021)), but not in CC direction (7.3 mm and 7. 8 mm (Z= -0.29,P =0.770)) between mDIBH and FB conditions. Conclusions The margins extended from CTV to PTV for EBPBI should be determined based on the respiratory status, border location and border direction.

Three-dimensional conformal partial breast external-beam irradiation after conservative surgery of the breast / 中华放射肿瘤学杂志

Objective To explore the methods, dosimetric features and short-term effects of partial breast irradiation carried out by three-dimensional external-beam irradiation (3DCPBI) assisted by active breathing control (ABC) . Methods Computed tomography (CT) simulation assisted by active breathing control (ABC) was carried out for each patient and intended to get CT images in condition of 75% deepest inspiration named moderate deep inspiration breath hold (mDIBH). The extent labeled by the silver slips located in the cavity was delineated as gross target volume (GTV) , GTV plus the margin of 15 mm was defined as planning target volume (PTV). 6 MV X-ray was selected as the radiation source and noncoplanar radiation with four three-dimensional conformal fields was used, the described dose was 34 Gy /10f/5d. The volume of GTV, PTV, the affected whole breast, and the percentage of PTV accounted for the affected whole breast , the percentages of PTV included by 100% , 95% and 90% isodose curve, the percentage of volume of the affected breast irradiated by 34. 0, 27. 2, 20. 4, 13. 6 and 6. 8 Gy , and Dmean,D5,V20 of the lungs and heart were calculated respectively. Acute radiation skin response was recorded and the cosmetic effect of the breast after radiotherapy were appraised, with the local tumor control and survival rate followed. Results The mean of volume ratio of PTV and affected whole breast was 14. 88% ; the mean of the volume covered by 90% isodose curve accounted for 92. 54% of the PTV; the volume irradiated by 34 Gy (100% of described dose) accounted for 17. 23% (mean) of the whole breast and 6. 8 Gy (20% of described dose) for 46. 11% , in other words, the volume covered by 20% of described dose was less than 50% of the whole breast. The Dmean, D5, V20 for the affected lateral lung were 1.97, 9. 25 Gy and 1. 58% , it was 0.20, 0. 87 Gy , and 0% for the unaffected lateral lung. The Dmean,D5, V20 for the heart was 0.65 Gy , 2. 82 Gy , and 0. 85%. Zero grade of acute radiation skin reaction was seen in 14 patients and gradel in 3 patients and there was not equal to or more than grade 2 of skin reaction for all the patients. Cosmetic effect were appeci-ated and satisfaction defined as excellent or good appearance of the irradiated breasts for all the patients. No recurrence of local tumor for all of the patients followed for one year. Therefore, the cosmetic result of 1 yr. follow - up was 100% and no recurence was found after 1 yr. follow - up. The 1-year tumor-free survival rate were all 100%. Conclusions For selected patients with early breast cancer after breast-conservative surgery, 3DCPBI assisted by ABC is feasible, however, the selection criteria for the patients, technique protocol and dose fractionation of 3DCPBI and its influence on late cosmetic effect, local tumor control and survival need to be continuously explored and observed in the future.

Value of CT on defining the gross tumor volume of non-small cell lung cancer / 中华放射肿瘤学杂志

Objective To study the value of CT on defining the gross tumor volume (GTV) in three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiation therapy(IMRT), by comparing the GTV contoured on preoperative CT with postoperative pathology guided GTV in patients with non-small cell lung cancer (NSCLC). Methods Thirty-three patients with histologically proved NSCLC had had CT scan of the thorax before sugery. We contoured the GTV for both primary tumor (GTV-T) and the regional metastatic lymph nodes (GTV-N) on preoperative CT scan. The GTV-T was defined on lung window while the GTV-N on mediastinal window. The metastatic lymph node was defined as≥ 10mm in diameter of short axis,while