1
|
Wang Y, Liu T, Chen H, Bai P, Zhan Q, Liang X. Comparison of internal target volumes defined by three-dimensional, four-dimensional, and cone-beam computed tomography images of a motion phantom. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:1488. [PMID: 33313233 PMCID: PMC7729323 DOI: 10.21037/atm-20-6246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background To explore the variations of the gross tumor volume (GTV) from different three-dimensional computed tomography (3DCT) scan modes and the consistency of internal target volume (ITV) between different 3DCT, cone-beam computed tomography (CBCT) and four-dimensional computed tomography (4DCT) scan, a study using a motion phantom simulating sinusoidal movement was conducted. Methods For three 3DCT scan modes: the GTV was contoured, and ITVI was generated on the basis of GTV with a 10-mm margin while ITVII and ITVIII with a 0-mm margin on the motion direction. ITVCBCT and ITVMIP were contoured on the images of CBCT and maximum-intensity projection (MIP) reconstructed 4DCT images. The centroid position shifts of ITVs were analyzed. The volume consistency between ITVI, ITVII, ITVIII and ITVMIP were evaluated by calculating the Dice similarity coefficient (Dsc) and the value of Δ Volume (ΔV). Furthermore, the 3DCT and CBCT images from 12 NSCLC patients were retrospectively collected, then the Dsc and ΔV were calculated. Results The mean ± standard deviation of centroid position of ITVI, ITVII and ITVIII were 2.3±4.7, 2.6±4.0, and 1.0±1.4 mm, respectively. The mean ± standard deviation of Dsc between ITVI, ITVII, ITVIII and ITVMIP were 0.78±0.77, 0.86±0.1, and 0.94±0.05, respectively. The ΔV of ITVI, ITVII, ITVIII were 29.67%, 17.22%, and 6.46%, respectively. The ITV from CBCT showed a deduction rate of 3.1-9.3% compared to 4DCT. For the patients, the mean Dsc andΔV between ITVI and ITVCBCT were 0.50 and 60.76%. Conclusions The GTV acquired from 3DCT scan mode I possessed great deviation of centroid position and target volume. ITV on the basis of this GTV was significantly larger than ITVMIP. A good similarity was showed between ITVIII and ITVMIP, 4DCT is still a golden standard for the ITV delineation, but in the absence of 4DCT, image from 3DCT scan mode III and KV-CBCT may be considered for ITV delineation with caution.
Collapse
Affiliation(s)
- Yu Wang
- Department of Oncology, Huashan Hospital North, Fudan University, Shanghai, China
| | - Tao Liu
- Department of Oncology, Huashan Hospital North, Fudan University, Shanghai, China.,Department of Oncology, Huashan Hospital, Fudan University, Shanghai, China
| | - Huiqin Chen
- Department of Radiotherapy, Zhangzhou Municipal Hospital, Fujian Medical University, Zhangzhou, China
| | - Penggang Bai
- Department of Radiotherapy, Fujian Provincial Cancer Hospital, Fujian Medical University, Fuzhou, China
| | - Qiong Zhan
- Department of Oncology, Huashan Hospital North, Fudan University, Shanghai, China.,Department of Oncology, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiaohua Liang
- Department of Oncology, Huashan Hospital North, Fudan University, Shanghai, China.,Department of Oncology, Huashan Hospital, Fudan University, Shanghai, China
| |
Collapse
|
2
|
ITV versus mid-ventilation for treatment planning in lung SBRT: a comparison of target coverage and PTV adequacy by using in-treatment 4D cone beam CT. Radiat Oncol 2020; 15:54. [PMID: 32127010 PMCID: PMC7055092 DOI: 10.1186/s13014-020-01496-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 02/18/2020] [Indexed: 12/25/2022] Open
Abstract
Background The internal target volume (ITV) approach and the mid-ventilation (MidV) concept are the two main respiratory motion-management strategies under free breathing. The purpose of this work was to compare the actual in-treatment target coverage during volumetric modulated arctherapy (VMAT) delivered through both ITV-based and MidV-based planning target volume (PTV) and to provide knowledge in choosing the optimal PTV for stereotactic body radiotherapy (SBRT) for lung lesions. Methods and materials Thirty-two lung cancer patients treated by a VMAT technique were included in the study. For each fraction, the mean time-weighted position of the target was localized by using a 4-dimensional cone-beam CT (4D-CBCT)-based image guidance procedure. The respiratory-correlated location of the gross tumor volume (GTV) during treatment delivery was determined for each fraction by using in-treatment 4D-CBCT images acquired concurrently with VMAT delivery (4D-CBCTin-treat). The GTV was delineated from each of the ten respiratory phase-sorted 4D-CBCTin-treat datasets for each fraction. We defined target coverage as the average percentage of the GTV included within the PTV during the patient’s breathing cycle averaged over the treatment course. Target coverage and PTVs were reported for a MidV-based PTV (PTVMidV) using dose-probabilistic margins and three ITV-based PTVs using isotropic margins of 5 mm (PTVITV + 5mm), 4 mm (PTVITV + 4mm) and 3 mm (PTVITV + 3mm). The in-treatment baseline displacements and target motion amplitudes were reported to evaluate the impact of both parameters on target coverage. Results Overall, 100 4D-CBCTin-treat images were analyzed. The mean target coverage was 98.6, 99.6, 98.9 and 97.2% for PTVMidV, PTVITV + 5mm, PTVITV + 4mm and PTVITV + 3mm, respectively. All the PTV margins led to a target coverage per treatment higher than 95% in at least 90% of the evaluated cases. Compared to PTVITV + 5mm, PTVMidV, PTVITV + 4mm and PTVITV + 3mm had mean PTV reductions of 16, 19 and 33%, respectively. Conclusion When implementing VMAT with 4D-CBCT-based image guidance, an ITV-based approach with a tighter margin than the commonly used 5 mm margin remains an alternative to the MidV-based approach for reducing healthy tissue exposure in lung SBRT. Compared to PTVMidV, PTVITV + 3mm significantly reduced the PTV while still maintaining an adequate in-treatment target coverage.
Collapse
|
3
|
The long- and short-term variability of breathing induced tumor motion in lung and liver over the course of a radiotherapy treatment. Radiother Oncol 2018; 126:339-346. [DOI: 10.1016/j.radonc.2017.09.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 09/01/2017] [Accepted: 09/03/2017] [Indexed: 11/19/2022]
|
4
|
Wang W, Li J, Zhang Y, Li F, Xu M, Fan T, Shao Q, Shang D. Comparison of patient-specific internal gross tumor volume for radiation treatment of primary esophageal cancer based separately on three-dimensional and four-dimensional computed tomography images. Dis Esophagus 2013; 27:348-54. [PMID: 23796234 DOI: 10.1111/dote.12089] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
To compare the target volume, position and matching index of the patient-specific internal gross tumor volume (IGTV) based on three-dimensional (3D) and four-dimensional (4D) computed tomography (CT) images for primary esophageal cancer. Twenty-nine patients with primary thoracic esophageal cancer underwent 3DCT and 4DCT scans during free breathing. IGTVs were constructed using three approaches: combining the gross target volumes from the 10 respiratory phases of the 4DCT dataset to produce IGTV10 ; IGTV2 was acquired by combining the two extreme phases; and IGTV3D was created from the 3DCT-based gross target volume by enlarging the 95th percentile of motion in each direction measured by the 4DCT. 0.16 cm lateral (LR), 0.14 cm anteroposterior (AP) and 0.29 cm superoinferior (SI) in the upper; 0.18 cm LR, 0.10 cm AP and 0.63 cm SI in the middle; and 0.40 cm LR, 0.58 cm AP and 0.82 cm in the lower thoracic esophagus could account for 95% of respiratory-induced tumor motion. The centroid position shift between IGTV10 and IGTV2 was all below 0.10 cm, and less than 0.20 cm between IGTV10 and IGTV3D . IGTV10 was bigger than IGTV2 ; the mean value of matching index for IGTV2 to IGTV10 was 0.87 ± 0.05, 0.85 ± 0.06 and 0.83 ± 0.05 for upper, middle and distal thoracic esophageal tumors, respectively, and just 0.57 ± 0.11, 0.56 ± 0.13 and 0.40 ± 0.03 between IGTV3D and IGTV10 . 4DCT-based IGTV10 is a reasonable patient-specific IGTV for primary thoracic esophageal cancer, and IGTV2 is considered as an acceptable alternative to IGTV10 . However, it seems unreasonable to use IGTV3D substitute IGTV10 .
Collapse
Affiliation(s)
- W Wang
- Department of Radiation Oncology, Shandong Tumor Hospital, Jinan, Shandong, China
| | | | | | | | | | | | | | | |
Collapse
|
5
|
Gong G, Yin Y, Guo Y, Liu T, Chen J, Lu J, Ma C, Sun T, Bai T, Zhang G, Li D, Wang R. Dosimetric differences among volumetric modulated arc radiotherapy (RapidArc) plans based on different target volumes in radiotherapy of hepatocellular carcinoma. JOURNAL OF RADIATION RESEARCH 2013; 54:182-189. [PMID: 22915784 PMCID: PMC3534270 DOI: 10.1093/jrr/rrs068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 07/10/2012] [Accepted: 07/11/2012] [Indexed: 06/01/2023]
Abstract
We investigated the dosimetric differences among volumetric-modulated arc radiotherapy (RapidArc, RA) plans designed for various target volumes in hepatocellular carcinoma (HCC). Ten HCC patients underwent 3D-CT scanning at free breathing (FB), 3D-CT at end inspiration hold (EIH) assisted by an Active Breathing Coordinator (ABC), and 4D-CT scanning. Gross tumor volumes (GTVs) were manually contoured on CT images. The individualized internal gross target volume (IGTV(1)) was obtained from 10 GTVs from 4D-CT images. Tumor individual margins were measured from GTV(FB) to IGTV(1). The IGTV(2) was obtained from GTV(FB) by applying individual margins. Four planning target volumes (PTV(1-4)) were obtained from IGTV(1), IGTV(2), GTV(FB), and GTV(EIH), respectively. An RA plan was designed for each of the PTVs (RA(1-4)). One 358° arc was used for PTVs(1-3), while three 135° arcs were used for PTV(4). It was found that PTV(2) and PTV(3) were larger than PTV(1) and PTV(4). The mean values of PTV(3)/PTV(1) and PTV(3)/PTV(4) were 2.5 and 1.9, respectively. The individual margins in the X, Y and Z axial directions varied greatly among these patients. There were no significant differences in the conformal index or homogeneity index among the four RA plans. RA(1) and RA(4) significantly reduced the radiation dose of normal liver tissue compared with RA(2) and RA(3) (P < 0.01). There were no significant differences between the radiation doses of the stomach and duodenum. RapidArc combined with 4D-CT or ABC technology is a promising method in radiotherapy of HCC, and accurately targeted the tumor volume while sparing more normal liver tissue.
Collapse
Affiliation(s)
| | - Yong Yin
- Corresponding author. Department of Radiation Oncology, Shandong Cancer Hospital, Shandong Provincial Key Laboratory of Radiation Oncology, Shandong Academy of Medical Sciences, 440 Jiyan Road, 250117 Jinan, China. Tel: +86-531-6762-6524; Fax: +86-531-6762-6427;
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Gong G, Yin Y, Xing L, Guo Y, Chen J, Liu T, Lu J, Ma C, Sun T, Bai T, Zhang G, Deng W. Comparison of Internal Target Volumes for Hepatocellular Carcinoma Defined Using 3DCT with Active Breathing Coordinator and 4DCT. Technol Cancer Res Treat 2011; 10:601-6. [PMID: 22066600 DOI: 10.1177/153303461101000610] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Guanzhong Gong
- Department of Radiation Oncology, Shandong Cancer Hospital Shandong Provincial Key Laboratory of Radiation Oncology Shandong Academy of Medical Sciences, No. 440 Jiyan Road, Jinan 250117, PR China
| | - Yong Yin
- Department of Radiation Oncology, Shandong Cancer Hospital Shandong Provincial Key Laboratory of Radiation Oncology Shandong Academy of Medical Sciences, No. 440 Jiyan Road, Jinan 250117, PR China
| | - Ligang Xing
- Department of Radiation Oncology, Shandong Cancer Hospital Shandong Provincial Key Laboratory of Radiation Oncology Shandong Academy of Medical Sciences, No. 440 Jiyan Road, Jinan 250117, PR China
| | - Yujie Guo
- Department of Radiation Oncology, Shandong Cancer Hospital Shandong Provincial Key Laboratory of Radiation Oncology Shandong Academy of Medical Sciences, No. 440 Jiyan Road, Jinan 250117, PR China
| | - Jinhu Chen
- Department of Radiation Oncology, Shandong Cancer Hospital Shandong Provincial Key Laboratory of Radiation Oncology Shandong Academy of Medical Sciences, No. 440 Jiyan Road, Jinan 250117, PR China
| | - Tonghai Liu
- Department of Radiation Oncology, Shandong Cancer Hospital Shandong Provincial Key Laboratory of Radiation Oncology Shandong Academy of Medical Sciences, No. 440 Jiyan Road, Jinan 250117, PR China
| | - Jie Lu
- Department of Radiation Oncology, Shandong Cancer Hospital Shandong Provincial Key Laboratory of Radiation Oncology Shandong Academy of Medical Sciences, No. 440 Jiyan Road, Jinan 250117, PR China
| | - Changsheng Ma
- Department of Radiation Oncology, Shandong Cancer Hospital Shandong Provincial Key Laboratory of Radiation Oncology Shandong Academy of Medical Sciences, No. 440 Jiyan Road, Jinan 250117, PR China
| | - Tao Sun
- Department of Radiation Oncology, Shandong Cancer Hospital Shandong Provincial Key Laboratory of Radiation Oncology Shandong Academy of Medical Sciences, No. 440 Jiyan Road, Jinan 250117, PR China
| | - Tong Bai
- Department of Radiation Oncology, Shandong Cancer Hospital Shandong Provincial Key Laboratory of Radiation Oncology Shandong Academy of Medical Sciences, No. 440 Jiyan Road, Jinan 250117, PR China
| | - Guifang Zhang
- Department of Radiation Oncology, Shandong Cancer Hospital Shandong Provincial Key Laboratory of Radiation Oncology Shandong Academy of Medical Sciences, No. 440 Jiyan Road, Jinan 250117, PR China
| | - Wei Deng
- Department of Radiation Oncology, Shandong Cancer Hospital Shandong Provincial Key Laboratory of Radiation Oncology Shandong Academy of Medical Sciences, No. 440 Jiyan Road, Jinan 250117, PR China
| |
Collapse
|
7
|
Wang Z, Lu X, Zhou G, Yan L, Zhang L, Zhu Y, Tian Y. Multiphase-computed tomography-based target volume definition in conventional fractionated radiotherapy of lung tumors: Dosimetric and reliable comparison with the technique using addition of generic margins. TUMORI JOURNAL 2011; 97:603-8. [DOI: 10.1177/030089161109700511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aims and background The aim of the present study was to compare radiotherapeutic plans based on internal target volume determined by between multiphase computed tomography and addition of a generic margin in lung tumors and to evaluate the reliability of ITV determined by multiphase computed tomography during conventional fractionated radiotherapy. Methods and study design The radiotherapeutic plans based on internal target volume determined by between multiphase computed tomography and addition of a generic margin in 10 patients with lung tumors were applied. The difference of two planning target volumes (PTV) and irradiated dose and volume of normal lung tissue were compared. Weekly new targets were delineated on repeated computed tomography scans, and weekly dose coverage of clinical target volume under two different treatment plans was evaluated. Results For all patients, PTV3CT volume based on multiphase computed tomography was significantly smaller than that of PTVcon based on addition of a generic margin (t = 6.831, P <0.001). The volume receiving more than 20 Gy in Plan3CT and Plancon was 16.7 ± 5.2% and 20.0 ± 5.2% (t = 7.565, P <0.001), the volume receiving more than 5 Gy was 36.6 ± 7.2% and 42.7 ± 6.4% (t = 7.459, P <0.001), and mean lung dose was 1037.5 ± 275.0 cGy and 1246.8 ± 271.0 cGy (t = 8.078, P <0.001), respectively. Both Plan3CT and Planconprovided a satisfactory clinical target volume coverage weekly during conventional fractionated radiotherapy for 6–7 weeks, and the ratio of the volume receiving the prescription dose was 1.03 ± 0.02 and 1.04 ± 0.02, respectively. Conclusions The radiotherapeutic plan based on internal target volume determined by multiphase computed tomography can ensure weekly target coverage during conventional fractionated radiotherapy in lung tumors, and it is better than the plan based on the addition of generic internal target volume, which can effectively reduce normal lung tissue irradiation.
Collapse
Affiliation(s)
- Zheng Wang
- Department of Radiation Oncology, Second Affiliated Hospital of Soochow University, Suzhou
- Department of Radiation Oncology, Changshu Affiliated Hospital of Soochow University, Suzhou, China
| | - Xueguan Lu
- Department of Radiation Oncology, Second Affiliated Hospital of Soochow University, Suzhou
| | - Gang Zhou
- Department of Radiation Oncology, Second Affiliated Hospital of Soochow University, Suzhou
| | - Liming Yan
- Department of Radiation Oncology, Second Affiliated Hospital of Soochow University, Suzhou
| | - Liyuan Zhang
- Department of Radiation Oncology, Second Affiliated Hospital of Soochow University, Suzhou
| | - Yaqun Zhu
- Department of Radiation Oncology, Second Affiliated Hospital of Soochow University, Suzhou
| | - Ye Tian
- Department of Radiation Oncology, Second Affiliated Hospital of Soochow University, Suzhou
| |
Collapse
|
8
|
Cai J, McLawhorn R, Read PW, Larner JM, Yin FF, Benedict SH, Sheng K. Effects of breathing variation on gating window internal target volume in respiratory gated radiation therapya). Med Phys 2010; 37:3927-34. [DOI: 10.1118/1.3457329] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
|
9
|
Gwynne S, Wills L, Joseph G, John G, Staffurth J, Hurt C, Mukherjee S. Respiratory movement of upper abdominal organs and its effect on radiotherapy planning in pancreatic cancer. Clin Oncol (R Coll Radiol) 2009; 21:713-9. [PMID: 19733469 DOI: 10.1016/j.clon.2009.07.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Revised: 07/16/2009] [Accepted: 07/20/2009] [Indexed: 12/22/2022]
Abstract
AIMS Radiotherapy for pancreatic cancer is complicated by the frequent overlapping of the planning target volume (PTV) and the organ at risk (OAR), limiting the dose that can be safely delivered to the tumour. Individualising the margins applied to the clinical target volume (CTV) may reduce OAR irradiation without increasing the risk of geographical miss. We quantified the movement of the pancreas with respiration and evaluated whether individualised margins based on this motion reduced the dose to OARs. MATERIALS AND METHODS Planning computed tomography scans were acquired in quiet breathing, held expiration and held inspiration. Organ motion was evaluated from displacement of a reproducible point within the pancreas in all directions. Two sets of plans (standard plan: P(stan); individualised plan incorporating movement data: P(ind)) were generated for each patient. The PTV and doses to OARs were evaluated for both sets of plans. RESULTS The mean (standard deviation) movement of the pancreas in the superior-inferior, lateral and anterior-posterior directions were 15.3 mm (4.3), 5.2 mm (3.5) and 9.7 mm (6.1), respectively. The use of individualised margins reduced the mean PTV volume by 33.5% (9.8) (P=0.0051). The proportional reductions in the percentage of kidney receiving >10 Gy, small bowel >45 Gy and liver >30 Gy were 63.7% (P=0.0051), 29.3% (P=0.0125) and 29.2% (P=0.0107), respectively. For the same level of OAR constraints, individualised margins allowed dose escalation in six of the 10 patients to a mean dose of 63.2 Gy. CONCLUSIONS The present study shows a simple way of incorporating organ motion into the planning process and can be adopted by any centre without major strain on healthcare resources. The use of individualised margins reduced PTV volume and the dose to OARs. This may offer an opportunity for dose escalation to try and further improve local control.
Collapse
Affiliation(s)
- S Gwynne
- Department of Clinical Oncology, Velindre Cancer Centre, Cardiff, UK
| | | | | | | | | | | | | |
Collapse
|
10
|
Zhao B, Yang Y, Li T, Li X, Heron DE, Huq MS. Image-guided respiratory-gated lung stereotactic body radiotherapy: which target definition is optimal? Med Phys 2009; 36:2248-57. [PMID: 19610314 DOI: 10.1118/1.3129161] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In stereotactic body radiotherapy (SBRT), the respiratory tumor motion makes target definition very important to achieve optimal clinical results for treatment of early stage lung cancer. In this article, the authors quantitatively evaluated the influence of different target definition strategies on image-guided respiratory-gated SBRT for lung cancer. Twelve lung cancer patients with 4D CT estimated target motion of >1 cm were selected for this retrospective study. An experienced physician contoured gross target volumes (GTVs) at each 4D CT phase for all patients. Three types of internal target volumes (ITVs) were generated based on the contoured GTVs:(1) ITVBH: GTV contoured on deep expiration breath-hold (BH) CT with an isotropic internal margin (IM) of 5 mm; (2) ITV50: GTV contoured at the end-expiration (50%) phase with an isotropic IM of 5 mm; (3) ITVGW: Composite volume of all GTVs within the gating window, defined as several phases around phase 50% with residual target motion of <5 mm. Planning target volumes (PTVs) were generated by adding 3 mm isotropic setup error margin to ITVs. Three treatment plans, namely, PlanBH, Plan50, and PlanGW, were created based on the three PTVs. Identical beam settings and planning constraints were used for all three plans for each patient. The prescription dose was 60 Gy in three fractions. The potential toxicities to the critical organs were quantified by mean lung dose (MLD), lung volume receiving >20 Gy (V20), mean heart dose (MHD), and spinal cord dose (SCD). It is shown that the tumor volume and dose coverage are comparable for PlanBH and Plan50. On average, PTVGW are 38% less than PTV50. Although for most patients PTV50 encompasses the entire PTVGW, up to 5.48 cm3 (6%) of PTVGW is outside PTV50. Compared to Plan50, prescribed percentage is about 2% higher for PlanGW, and the average dose decreases in critical organs are 0.78 Gy for MLD, 1.02% for V20, 0.61 Gy for MHD and 0.59 Gy for maximum SCD. For the cases receiving high lung and heart dose with Plan50, the dose reduction is 1.0 Gy for MLD and 1.14 Gy for MHD with PlanGW. Our preliminary results show that a patient-specific ITV, defined as the composite volume of all GTVs within the gating window, may be used to define PTV in image-guided respiratory-gated SBRT. This approach potentially reduces the irradiated volume of normal tissue further without sacrificing target dose coverage and thus may minimize the risk of treatment-related toxicities.
Collapse
Affiliation(s)
- Bo Zhao
- Department of Radiation Oncology, University of Pittsburgh Cancer Institute, 5230 Centre Avenue, Pittsburgh, Pennsylvania 15232, USA
| | | | | | | | | | | |
Collapse
|
11
|
Use of Maximum Intensity Projections (MIPs) for Target Outlining in 4DCT Radiotherapy Planning. J Thorac Oncol 2008; 3:1433-8. [DOI: 10.1097/jto.0b013e31818e5db7] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|