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Title: SU-E-T-625: Potential for Reduced Radiation Induced Toxicity for the Treatment of Inoperable Non-Small-Cell Lung Cancer Using RapidArc Planning

Abstract

Purpose: To investigate the feasibility of using RapidArc (RA) treatment planning to reduce irradiation volume of normal lung and other organs at risk (OARs) in the treatment of inoperable non-small-cell lung cancer (NSCLC) patients. Methods: A retrospective treatment planning and delivery study was performed to compare target coverage and the volumes of the normal lung, spinal cord, heart and esophagus on 4D-CT scan above their dose tolerances delivered by RA vs. IMRT for ten inoperable NSCLC patients (Stage I-IIIB). RA plans consisted of either one-full or two-partial co-planar arcs used to treat 95% of the planning target volume (PTV) with 6MV beam to a prescription of 66Gy in 33 fractions. IMRT plans were generated using 5–7 co-planar fields with 6MV beam. PTV coverage, dose-volume histograms, homogeneity/conformity indices (CI), total number of monitor units(MUs), beam-on time and delivery accuracy were compared between the two treatment plans. Results: Similar target coverage was obtained between the two techniques. RA (CI=1.02) provided more conformal plans without loss of homogeneity compared to IMRT plans (CI=1.12). Compared to IMRT, RA achieved a significant median dose reduction in V10 (3%), V20 (8%), and mean lung dose (3%) on average, respectively. On average, V5 was comparable between themore » two treatment plans. RA reduced mean esophagus (6%), mean heart (18%), and maximum spinal cord dose (7%), on average, respectively. Total number of MUs and beam-on time were each reduced almost by a factor of 2 when compared to IMRT-patient comfort, reduced intra-fraction-motion and leakage dose. The average IMRT and RA QA pass rate was about 98% for both types of plans for 3%/3mm criterion. Conclusion: Compared to IMRT plans, RA provided not only comparable target coverage, but also improved conformity, treatment time, and significant reduction in irradiation of OARs. This may potentially allow for target dose escalation without increase in normal tissue toxicity.« less

Authors:
; ; ; ; ;  [1]
  1. University of Kansas Hospital, Kansas City, KS (United States)
Publication Date:
OSTI Identifier:
22538134
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 42; Journal Issue: 6; Other Information: (c) 2015 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; 61 RADIATION PROTECTION AND DOSIMETRY; ESOPHAGUS; HEART; LUNGS; NEOPLASMS; RADIATION DOSE DISTRIBUTIONS; RADIATION DOSES; RADIATION MONITORS; RADIOTHERAPY; SPINAL CORD; TOXICITY; VERTEBRAE

Citation Formats

Pokhrel, D, Sood, S, Badkul, R, Jiang, H, Saleh, H, and Wang, F. SU-E-T-625: Potential for Reduced Radiation Induced Toxicity for the Treatment of Inoperable Non-Small-Cell Lung Cancer Using RapidArc Planning. United States: N. p., 2015. Web. doi:10.1118/1.4924988.
Pokhrel, D, Sood, S, Badkul, R, Jiang, H, Saleh, H, & Wang, F. SU-E-T-625: Potential for Reduced Radiation Induced Toxicity for the Treatment of Inoperable Non-Small-Cell Lung Cancer Using RapidArc Planning. United States. doi:10.1118/1.4924988.
Pokhrel, D, Sood, S, Badkul, R, Jiang, H, Saleh, H, and Wang, F. Mon . "SU-E-T-625: Potential for Reduced Radiation Induced Toxicity for the Treatment of Inoperable Non-Small-Cell Lung Cancer Using RapidArc Planning". United States. doi:10.1118/1.4924988.
@article{osti_22538134,
title = {SU-E-T-625: Potential for Reduced Radiation Induced Toxicity for the Treatment of Inoperable Non-Small-Cell Lung Cancer Using RapidArc Planning},
author = {Pokhrel, D and Sood, S and Badkul, R and Jiang, H and Saleh, H and Wang, F},
abstractNote = {Purpose: To investigate the feasibility of using RapidArc (RA) treatment planning to reduce irradiation volume of normal lung and other organs at risk (OARs) in the treatment of inoperable non-small-cell lung cancer (NSCLC) patients. Methods: A retrospective treatment planning and delivery study was performed to compare target coverage and the volumes of the normal lung, spinal cord, heart and esophagus on 4D-CT scan above their dose tolerances delivered by RA vs. IMRT for ten inoperable NSCLC patients (Stage I-IIIB). RA plans consisted of either one-full or two-partial co-planar arcs used to treat 95% of the planning target volume (PTV) with 6MV beam to a prescription of 66Gy in 33 fractions. IMRT plans were generated using 5–7 co-planar fields with 6MV beam. PTV coverage, dose-volume histograms, homogeneity/conformity indices (CI), total number of monitor units(MUs), beam-on time and delivery accuracy were compared between the two treatment plans. Results: Similar target coverage was obtained between the two techniques. RA (CI=1.02) provided more conformal plans without loss of homogeneity compared to IMRT plans (CI=1.12). Compared to IMRT, RA achieved a significant median dose reduction in V10 (3%), V20 (8%), and mean lung dose (3%) on average, respectively. On average, V5 was comparable between the two treatment plans. RA reduced mean esophagus (6%), mean heart (18%), and maximum spinal cord dose (7%), on average, respectively. Total number of MUs and beam-on time were each reduced almost by a factor of 2 when compared to IMRT-patient comfort, reduced intra-fraction-motion and leakage dose. The average IMRT and RA QA pass rate was about 98% for both types of plans for 3%/3mm criterion. Conclusion: Compared to IMRT plans, RA provided not only comparable target coverage, but also improved conformity, treatment time, and significant reduction in irradiation of OARs. This may potentially allow for target dose escalation without increase in normal tissue toxicity.},
doi = {10.1118/1.4924988},
journal = {Medical Physics},
number = 6,
volume = 42,
place = {United States},
year = {Mon Jun 15 00:00:00 EDT 2015},
month = {Mon Jun 15 00:00:00 EDT 2015}
}
  • Purpose: To compare and analyze the characteristics of intensity-modulated arc therapy(IMAT) versus fixed-gantry intensity-modulated radiotherapy(IMRT) in treatment of non-small-cell lung cancer. Methods: Twelve patients treated in our radiotherapy center were selected for this study. The patient subsequently underwent 4D-CT simulation.Margins of 5mm and 10mm were added to the ITV to generate the CTV and PTV respectively. Three treatment plans (IMRT,one single arc (RA1),double arcs (RA2))were generated with Eclipse ver.8.6 planning systems. Using a dose level of 75Gy in 15fractions to the ITV,60Gy in 15fractions to the CTV and 45Gy in 15fractions to the PTV respectively. The target and normol tissuemore » volumes were compared,as were the dosimetry parameters. Results: There were no significant differences in CI of ITV,PTV,HI of ITV,CTV and PTV, V5,V10,V15,V20,V25,V30,V45,V50 of total-lung and mean lung dose (all p>0.05). However, the differences were significant in terms of CI of CTV,V5 of B-P (all p<0.05). On the MU, IMRT=1540MU,RA1=1006 MU and RA2=1096 MU. (F=12.00,P=0.000).On the treatment time, IMRT= 13.5min,RA1= 1.5min,and RA2=2.5 min (F= 30.11,P=0.000 ). Conclusion: IMAT is equal to IMRT in dosimetril evaluation. Due to much less Mu and delivery time,IMAT is an ideal technique in treating patients by reduceing the uncomfortable influnce which could effect the treatment.« less
  • Purpose: To compare normal lung-sparing capabilities of three advanced radiation therapy techniques for locally advanced non-small cell lung cancer (LA-NSCLC). Methods: Four-dimensional computed tomography (4DCT) was performed in 10 patients with stage IIIb LA-NSCLC. The internal target volume (ITV); planning target volume (PTV); and organs at risks (OARs) such as spinal cord, total normal lung, heart, and esophagus were delineated for each CT data set. Intensity-modulated radiation therapy (IMRT), Tomohelical-IMRT (TH-IMRT), and TomoDirect-IMRT (TD-IMRT) plans were generated (total prescribed dose, 66 Gy in 33 fractions to the PTV) for each patient. To reduce the normal lung dose, complete and directionalmore » block function was applied outside the normal lung far from the target for both TH-IMRT and TD-IMRT, while pseudo- OAR was set in the same region for IMRT. Dosimetric characteristics of the three plans were compared in terms of target coverage, the sparing capability for the OAR, and the normal tissue complication probability (NTCP). Beam delivery efficiency was also compared. Results: TH-IMRT and TD-IMRT provided better target coverage than IMRT plans. Lung volume receiving ≥–30 Gy, mean dose, and NTCP were significant with TH-IMRT than with IMRT (p=0.006), and volume receiving ≥20–30 Gy was lower in TD-IMRT than in IMRT (p<0.05). Compared with IMRT, TH-IMRT had better sparing effect on the spinal cord (Dmax, NTCP) and heart (V45) (p<0.05). NTCP for the spinal cord, V45 and V60 for the heart, and Dmax for the esophagus were significantly lower in TD-IMRT than in IMRT. The monitor units per fraction were clearly smaller for IMRT than for TH-IMRT and TD-IMRT (p=0.006). Conclusion: In LA-NSCLC, TH-IMRT gave superior PTV coverage and OAR sparing compared to IMRT. TH-IMRT provided better control of the lung volume receiving ≥5–30 Gy. The delivery time and monitor units were lower in TD-IMRT than in TH-IMRT.« less
  • Purpose: To prospectively assess the feasibility, toxicity, and local control of a class solution protocol of moderately hypofractionated tomotherapy in Stage III, inoperable, locally advanced non-small-cell lung cancer patients. Methods and Materials: Eligible patients were treated according to a uniform class solution (70.5 Gy in 30 fractions) with fixed constraints and priorities using helical tomotherapy. Toxicity monitoring was performed using the Radiation Therapy Oncology Group criteria and the National Cancer Institute Common Terminology Criteria and Adverse Events (CTCAE) version 3.0. Pulmonary function tests were performed at the start and repeated at 3 months after treatment. Results: Our class solution resultedmore » in a deliverable plan in all 40 consecutive patients. Acute Grade 3 lung toxicity was seen in 10% of patients. Two patients died during acute follow-up with pulmonary toxicity. Correlations were found between changes in pulmonary function test results and mean lung dose or the lung volume receiving 20 Gy (V{sub 20}). The correlation was strongest for lung diffusion capacity for carbon monoxide. A V{sub 20} of >27% and >32% were predictive for Grades 2 and 3 acute lung toxicity respectively (p < 0.05). Late Grade 3 toxicity was exclusively pulmonary, with an incidence of 16%. Overall Grade 3 lung toxicity correlated with a mean lung dose of >18 Gy and a median lung dose of >5 Gy (p < 0.05). Median survival was 17 months, and the 1-year and 2-year local progression-free survivals were 66% and 50%, respectively. Conclusion: The current class solution using moderately hypofractionated helical tomotherapy in patients with locally advanced non-small-cell lung cancer is feasible. Toxicity was acceptable and in line with other reports on intensity-modulated radiotherapy. The local progression-free survival was encouraging considering the unselected population.« less
  • Purpose: To study breathing related tumor motion amplitudes by lung lobe location under controlled breathing conditions used in Stereotactic Body Radiation Therapy (SBRT) for NSCLC. Methods: Sixty-five NSCLC SBRT patients since 2009 were investigated. Patients were categorized based on tumor anatomic location (RUL-17, RML-7, RLL-18, LUL-14, LLL-9). A 16-slice CT scanner [GE RT16 Pro] along with Varian Realtime Position Management (RPM) software was used to acquire the 4DCT data set using 1.25 mm slice width. Images were binned in 10 phases, T00 being at maximum inspiration ' T50 at maximum expiration phase. Tumor volume was segmented in T50 using themore » CT-lung window and its displacement were measured from phase to phase in all three axes; superiorinferior, anterior-posterior ' medial-lateral at the centroid level of the tumor. Results: The median tumor movement in each lobe was as follows: RUL= 3.8±2.0 mm (mean ITV: 9.5 cm{sup 3}), RML= 4.7±2.8 mm (mean ITV: 9.2 cm{sup 3}), RLL=6.6±2.6 mm (mean ITV: 12.3 cm{sup 3}), LUL=3.8±2.4 mm (mean ITV: 18.5 cm{sup 3}), ' LLL=4.7±2.5 mm (mean ITV: 11.9 cm{sup 3}). The median respiratory cycle for all patients was found to be 3.81 ± 1.08 seconds [minimum 2.50 seconds, maximum 7.07 seconds]. The tumor mobility incorporating breathing cycle was RUL = 0.95±0.49 mm/s, RML = 1.35±0.62 mm/s, RLL = 1.83±0.71 mm/s, LUL = 0.98 ±0.50 mm/s, and LLL = 1.15 ±0.53 mm/s. Conclusion: Our results show that tumor displacement is location dependent. The range of motion and mobility increases as the location of the tumor nears the diaphragm. Under abdominal compression, the magnitude of tumor motion is reduced by as much as a factor of 2 in comparison to reported tumor magnitudes under conventional free breathing conditions. This study demonstrates the utility of abdominal compression in reducing the tumor motion leading to reduced ITV and planning tumor volumes (PTV)« less
  • Purpose: To investigate a novel Integrated VMAT/IMRT technique which combines volumetric modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) for non-small cell lung cancer (NSCLC). Methods: 2 partial arcs VMAT, 5-field IMRT and Integrated VMAT/IMRT plans were created for 17 patients with NSCLC. The Integrated VMAT/IMRT technique consisted of 2 partial VMAT arcs and 5 IMRT fields. The dose distribution of planning target volume (PTV) and organs at risk (OARs) for Integrated VMAT/IMRT was compared with IMRT and VMAT. The monitor units (MUs) and treatment delivery time were also evaluated. For each plan, a dry run was performedmore » to assess the dosimetric accuracy with MatriXX from IBA. Results: Integrated VMAT/IMRT significantly improved the target conformity and homogeneity. The V30 of normal lung for Integrated plans was significantly lower than IMRT plans (8.4% vs 9.2%; p<0.05). The V5 and mean lung dose (MLD) of normal lung for Integrated plans were 9.8% and 4.6% lower than VMAT plans (p<0.05). The maximum dose of spinal cord for Integrated plans was 4.9 Gy lower than IMRT plans (p<0.05). The mean delivery time of IMRT, VMAT and Integrated plans was 280 s, 114 s, and 327 s, respectively. The mean MUs needed for IMRT, VMAT and Integrated plans were 933, 512, and 737, respectively. The gamma pass rates were beyond 90% at the 3%/3 mm criteria when the gantry angles were set to 0° for pretreatment verification. Conclusion: Integrated VMAT/IMRT technique significantly reduced V5, V10 and MLD of normal lung compared with VMAT, and the irradiated volume of the OARs receiving medium to high dose with fewer MUs compared with IMRT. Integrated VMAT/IMRT technique can be a feasible radiotherapy technique with better plan quality and accurately delivered on the linear accelerator. Ruijie Yang was funded by the grant project: National Natural Science Foundation of China (No. 81071237). Other authors have no competing interest for this work.« less