Research on the precision and stability of optical surface imaging technology in guiding radiotherapy positioning / 中华放射肿瘤学杂志

Objective To investigate the precision and stability of optical surface imaging (OSI)system Catalyst in guiding radiotherapy positioning.Methods A total of 52 patients with five different tumor sites who underwent cone-beam computed tomography (CBCT)-guided radiotherapy were recruited in this investigation.For the first treatment fraction,the setup error was recorded as C after online CBCT correction,and the surface images of patients taken by Catalyst were set as the reference images Cref.For the following treatment fraction,patients were pre-corrected according to the Catalyst Cref image with the acceptable errors within 2 mm/ 2,and the pre-corrected errors were recorded as C1.Then,after online CBCT correction,the setup errors were recorded as C.The errors between post-corrected Catalyst surface image and Cref image were recorded as C2.For each treatment fraction,the difference between Catalyst correction errors C1 and CBCT corrected errors C was recorded as d1,and the difference between the post-corrected Catalyst errors C2 and Cref image was recorded as d2.d3=d1-d2.The values of d1 and d3 in the 6 dimensions were analyzed using single sample t-test.The correlation between C-C1 and d1-d2 was statistically analyzed by Pearson correlation analysis.Results The mean value of d1 and d3 for 52 patients were within 2 mm/2 °.CBCT-C1 and d1-d2 were both significantly correlated (R =3,7,P=0.00,0.01).Conclusions OSI system yield high accuracy and stability in radiotherapy positioning,which is of certain significance in radiotherapy positioning for cancer patients.

Application of active breathing control (ABC) and four dimensional CT technology in stereotactic radiotherapy of lung tumor / 中华放射医学与防护杂志

Objective To investigate the difference of lung and target volume and dosimetry characteristics features of deep inhalation breathing holding-active breathing control (ABC) and the four dimensional CT (4D-CT) free breathing in stereotactic body radiation therapy (SBRT) technology for patients with lung cancer.Methods 10 patients with pulmonary malignant tumor who were proposed SBRT treatment were selected,and received CT under free breath (FB-CT),4D-CT scan under quiet respiration (4D-CT) and active breathing control CT scan (ABC-CT),respectively.With SBRT technology under the same condition designed four corresponding plans,FB-CT,ABC-CT,4D-CT and 4D-CT0 which was the end inspiratory phase of 4D-CT respectively.The lung volume(V),PTV,V5,V20,mean lung dose(MLD) and normal tissue complication probability(NTCP) of four treatment programs were counted and compared.Results Compared with FB-CT,V,PTV,V5,V20,MLD and NTCP of ABC-CT were 51.48％,-65.34％,-42.64％,-56.62％,-40.22％ and-98.53％ (t=-7.14 to6.16,P＜0.05);PTV,V5,V20,MLD and NTCP of 4D-CT were-40.14％,-16.90％,-37.16％,-17.85％ and-90.96％ (t =0.54 to 3.22,P＜0.05);PTV,V5,V20,MLD and NTCP of 4D-CT0 were-68.98％,-30.21％,-48.49％,-37.45％ and-95.82％ (t=1.32 to 5.46,P＜0.05),respectively.Compared with FB-CT,the lung volume of 4D-CT and 4D-CT0 had no statistical difference (P ＞ 0.05).Conclusions ABC-CT methods have ideal clinical characteristics,with larger double lung volume,smaller artifacts of image,and higher target matching precision.ABC-CT methods reduce the dose of normal lung tissues significantly.

Comparison study on 4D-CT and ABC techniques in respiratory management during lung radiotherapy / 重庆医学

Objective To evaluate the similarities and differences between four-dimensional radiotherapy (4D-CT ) and active breathing control techniques(ABC) in respiratory management in lung radiotherapy ,and investigate the indications and feasibility of different breathing control techniques for different patients .Methods Twenty-one patients treated with lung radiotherapy received respiratory management .4D-CT technology was used in 11 patients ,while ABC technology was adopted in the rest 10 .The ratios of planning target volume(PGTV) to gross tumor volume(GTV)[(PGTV/GTV)] were calculated .The differences between these two respiratory management technologies were compared in terms of the PGTV ,positioning time ,planning time and treatment time to investigate the indications .Results 4D-CT technology had higher PGTV/GTV ratio ,and shorter positioning time and irradiation time than ABC technology(P0 .05) .In patients with ABC and 4D-CT technology ,objective response rates were 50 .0% ,45 .5% ,respectively ,and the radiation pneumonitis rates were 30 .0% ,27 .3% ,respectively .There was no significant difference in both groups (P>0 .05) .Conclusion In lung tumor radiothera-py ,ABC can reduce irradiation volume ,suitable for patients with good performance status .4D-CT is time-saving and well tolerated , suitable for patients with smaller tumors .

Comparison of the position and volume of esophagus between quiet end-inspiration and end-expiration three dimensional CT assisted with active breathing control and corresponding phases in four dimensional CT / 中华放射医学与防护杂志

Objective To compare the position,volume and matching index (MI) of esophagus between quiet end-inspiration and end-expiration in three dimensional CT (3D-CT) assisted with active breathing control (ABC) and the corresponding phases in four dimensional CT (4D-CT).Methods Eleven patients with peripheral lung cancer underwent 4D-CT simulation scan and 3D-CT simulation scans in end-inspiratory hold (CTEIH) and end-expiratory hold (CTEEH) in succession.The 0％ phase was defined as end-inspiratory phase (CT0),while the 50％ phase was defined as end-expiratory phase (CT50).The proximal,mid-,and distal thoracic esophagus were delineated separately on CT0,CT50,CTEIH and CTEEH images.The position,volume and MI of each segment esophagus between CT0 and CTEIH,CT50 and CTEEH were compared.Results In the left-right (x) direction,the position differences in the proximal,mid-,and distal thoracic esophagus between CT0and CTEIH were (-0.02 ±0.16)cm,(0.06 ± 0.26)cm and (0.10 ± 0.33) cm respectively,and in the anterior-posterior (y) direction,the position differences were (0.04 ±0.24)cm,(0.04 ±0.12) cm and (0.08 ±0.15) cm respectively,and the position differences in the same direction were not statistically significant.In the x direction,the position differences of the proximal,mid-,or distal thoracic esophagus between CT50 and CTEEH were (-0.02 ±0.24) cm,(0.12 ± 0.37) cm and (0.26 ± 0.33) cm respectively,and in the y direction,the position differences were (0.03 ±0.21)cm,(0.04 ±0.17)cm and (0.14 ±0.18)cm respectively,and the position differences in x and y directions of proximal and mid-thoracic esophagus between CT50 and CTEEH were not statistically significant,while the position differences in x and y directions of distal thoracic esophagus between CT50and CTEEH were both statistically significant (t =0.025,0.024,P ＜ 0.05).The volumes of the proximal,mid-and distal thoracic esophagus were all larger in CT0and CT50 than those in CTEIHand CTEEH,but without statistical differences.The MIs of the volumes of the proximal,mid-and distal thoracic esophagus between CT0 and CTEIH were (0.50 ± 0.17),(0.50 ± 0.19) and (0.56 ± 0.08),respectively,and those between CT50and CTEEH were (0.50 ±0.16),(0.47 ±0.14) and (0.51 ±0.15),respectively.The MI of each segment esophagus between CT0and CTEIHwas larger than that between CT50 and CTEEH,but without statistical differences.Conclusions The influence of breathing modes on the centroid positions of the proximal,mid-thoracic normal esophagus were not significant and there were spatial mismatches for any segment esophagus between 3D-CT assisted with ABC and 4D-CT.

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.

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.

The individual internal gross target volume for hepatocellular carcinoma: four-dimensional CT vs three-dimensional CT associated with active breathing control / 中华放射肿瘤学杂志

Objective To research the feasibility of using three-dimensional CT (3DCT) associated with active breathing control (ABC) in determination of the individual internal tumor volume (ITV) for hepatocellular carcinoma (HCC) comparing the four-dimensional CT (4DCT).Methods After 4DCT scans of 15 HCC patients who had accepted TACE,completed the 3DCT scans associated with ABC in three ways of breathing:free breathing ( FB),end inspiration hold ( EIH),end expiration hold (EEH).4DCT images were sorted into 10 phases and the maximum intensity projection (MIP) images were constructed.The GTVs were manually contoured on 4DCT and 3DCT images (labeled as GTV0,GTV10.….GTV90,GTVMIP,,GTVFB,GTVEIH and GTVEEH).GTV0…GTV90,GTV0 and GTV50,GTV0,GTV20 and GTV50,GTVEIH and GTVEEH were respectively merged into IGTV1,IGTV2,IGTV3,IGTV4.The volume and geometry displacement of GTVs and IGTVs were compared.Results All patients were compatible with the ABC technique and completed the CT scans in two ways.The motion of diaphragm measured between 4DCT and 3DCT images was not significantly different ( 1.39 cm and 1.39 cm,t =-0.02,P =0.983 ),it was similar to the volume difference among GTV0,GTV20,GTV50,GTVEIH,GTVEEH and GTVFB (56.4,54.6,55.5,55.6,55.2,59.7 cm3,F =0.01,P =1.000 ).The comparison result of volume difference among IGTV1,IGTV2,IGTV3,IGTV4 and GTVMIP (77.9,71.4,73.4,72.3 and 66.3 cm3,F =0.02,P =1.000)were similar to the differences of geometry displacement in x,y and z axial among them (F =0.48,0.04,0.02,P =0.750,0.997,0.999,respectively).Conclusion The application of 3DCT associated with ABC in determination of the individual IGTV for HCC is feasible and safe comparing to 4DCT.

Primary application of active breathing control system in conformal radiotherapy for patients with non-small cell lung cancer / 中华放射肿瘤学杂志

Objective To evaluate the feasibility of active breathing control (ABC) in conformal radiotherapy (CRT) for patients with non-small cell lung cancer (NSCLC). Methods From Feb 2005 to Mar 2008, 29 patients with inoperable NSCLC (stage Ⅱ-Ⅳ) were evaluated. For each patient, two series of CT scans were obtained with free breathing (FB) and ABC system during simulation, respectively. Then two confonnal radiotherapy (CRT) plans were finished based on the two sets of reconstructed images. The pattern of post-inspiratory breath-hold was triggered at 80% of the peak of inspiration curve. The margin of clinical target volume (CTV) to planning target volume (PTV) was 0. 6 cm for lesions of the superior lobe, and 1.0 cm for the lesions of middle and inferior lobes. Three to five coplanar fields were performed in conformal radiotherapy. The gross tumor volume (GTV), CTV, PTV, volume of the bilateral lungs (Volume_(lung)), V_(20) and mean lung dose (MLD) of two plans were evaluated by dose-volume histogram (DVH). The World Health Organization criteria and National Cancer Institute Common Toxicity Criteria 3.0 (NCI-CTC3.0) scale were used to assess the immediate response and acute side-effect, respectively. Results Significant differences of GTV, CTV, FIN, Volum_(lung), V_(20) and MDL were observed between the two plans (36. 35 cm~3 vs. 31.40 cm~3, t = 9. 70, P <0. 001 ;82. 33 cm~3 vs. 70. 83 cm~3, t = 8. 19, P < 0. 001 ; 230. 73 cm~3 vs. 197.59 cm~3 ,t=5.72,P <0. 001 ;21.66% vs. 18. 76% ,t = 11.16,P <0. 001 ;1329. 07 Gy vs. 1143. 14 Gy, t = 13. 24, P < 0. 001). With ABC, all patients completed their treatment successfully except one patient for financial problems. The median radiation dose to the GTV was 64 Gy (60 -64 Gy). The overall immediate response rate was 64% (18/28). According to the NCI-CTC 3.0, grade 1 and 2 acute radiation-related toxicities occurred in 68% (19/28) and 18% (5/28) of patients for esophagitis, 82% (23/28) and 7% (2/28) for pneumonitis, respectively. Grade 1, 2 and 3 bone marrow suppression occurred in 57% (16/28), 25% (7/28) and 14% (4/28) of patients, respectively. Grade 1 and 2 acute cardiac injuries occurred in 86% (24/28) and 14% (4/28) of patients. Conclusions During CRT for patients with NSCLC, the use of ABC can decrease the radiation dose and acute complications of normal tissues.

The study of target delineation and target movement of whole breast assisted by active breathing control in intensity modulated radiotherapy after breast conservative surgery / 中华放射医学与防护杂志

Objective To explore the influence of different delineators and different delineating time on target determination of the whole breast and to explore intrafraction and interaction target displacements of the breast on moderate deep inspiration breathing hold (mDIBH) assisted by active breathing control (ABC) after breast conservative surgery. Methods Twenty patients received primary CT-simulation assisted by ABC to get five sets of CT image on the three breathing condition which included one set from free breath ( FB), two sets from mDIBH and two sets from deep expiration breathing control (DEBH). After radiotherapy with ten to fifteen fractions, the repeat CT-simulation was carried out to get the same five sets of CT image as the primary CT-simulation. The whole breast target were delineated at different time by the same delineator and delineated respectively by five delineators on the first set of CT images got with mDIBH from the primary CT-simulation,and to compare the influence of delineator and delineating time on the whole breast target. The total silver clips in the cavity were marked respectively on the two sets of CT images got with mDIBH from the primary CT-simulation, and to compare the intrafraction displacement of geometric body structured by the total of silver clips. The two ribs near the isocentric plane of the breast target were delineated respectively on two sets of the mDIBH CT image from the primary CT-simulation and on one set of the mDIBH CT image from the repeat CT-simulation, and comparing the movement of the point of interest (POI) of the ribs delineated to get the value of intrafraction and interfraction thoracic expansion. Results There was not statistically significant between the four volumes of whole breast targets delineated by the same delineator at different time, but with statistics significant between the volumes of whole breast target delineated by the different delineators(F = 19.681, P = 0.000). There was not statistically significant between the intrafraction displacements of the POI of the geometric body at each direction, and with no statistically significant between intrafraction displacements of the POI of the ribs delineated on the same mDIBH condition. There was not statistically significant between the interfraction displacements of the POI of the ribs delineated. Conclusions The influence of different delineators on the whole breast target is statistically significant. The difference of displacement of the breast target with the same mDIBH eondition assisted by ABC at the different direction is not statistically significant.

The displacement of silver clips in breast cavity during kV-plain film guided three-dimensional con-formal external-beam partial breast irradiation assisted by active breathing control / 中华放射肿瘤学杂志

Objective To measure the displacement of the silver clips guided by kV-plain film at state of moderate deep inspiration hold(mDIBH) assisted by active breathing control(ABC) and to explore the margin of clinical target volume(CTV) to planning target volume(PTV) for breast cancer patients treated with three-dimensional conformal external-beam partial breast irradiation (EB-PBI) assisted by ABC. Methods The patients undertook CT simulation assisted by ABC to get the CT images on the respiratory condition of mDIBH. Four selected silver clips in breast cavity were delineated and the cavity based on all of the clips were delineated as gross tumor volume (GTV). Before each irradiation, two orthogonal kV-plain films were taken for the patients in the respiratory condition of mDIBH assisted by ABC device. 2D-2D auto-matie registration was performed based on pixel between the kV-plain films and the digital reconstructed radi-ographs(DRR). Then manual registration was undertook to get the shifts of the four clips separately at LAT, LNG,and VRT directions. Based on the shift data,the margins of CTV to PTV at LAT,LNG and VRT direc-tions were calculated. Results The margins from CTV to PTV were 5.00 mm,7.78 mm and 9.30 mm at LAT,LNG and VRT directions based on the clip at cephal border of the cavity. The corresponding margins were 4.40 mm,6.43 mm and 6.73 mm based on the clip at bottom of the cavity;5.04 mm,8.63 mm and 10.54 mm based on the clip at lateral border of the cavity;5.40 mm,8.59 ram and 10.81 mm based on the clip at pedal border of the cavity. Conclusions The silver clips in breast cavity can be clearly showed on the kV-plain film. The displacement of the clips can be exactly measured by registration of kV-plain film and planning DRR in condition of mDIBH assisted by ABC. The margins from CTV to PTV for EB-PBI can be calculated based on the displacement of the clips.

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.