skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: SU-E-T-13: A Comparative Dosimetric Study On Radio-Dynamic Therapy for Pelvic Cancer Treatment: Strategies for Bone Marrow Dose and Volume Reduction

Abstract

Purpose: Radio-dynamic therapy (RDT) is a potentially effective modality for local and systemic cancer treatment. Using RDT, the administration of a radio-sensitizer enhances the biological effect of high-energy photons. Although the sensitizer uptake ratio of tumor to normal tissue is normally high, one cannot simply neglect its effect on critical structures. In this study, we aim to explore planning strategies to improve bone marrow sparing without compromising the plan quality for RDT treatment of pelvic cancers. Methods: Ten cervical and ten prostate cancer patients who previously received radiotherapy at our institution were selected for this study. For each patient, nine plans were created using the Varian Eclipse treatmentplanning-system (TPS) with 3D-CRT, IMRT, and VMAT delivery techniques containing various gantry angle combinations and optimization parameters (dose constraints to the bone marrow). To evaluate the plans for bone marrow sparing, the dose-volume parameters V5, V10, V15, V20, V30, and V40 for bone marrow were examined. Effective doseenhancement factors for the sensitizer were used to weigh the dose-volume histograms for various tissues from individual fractions. Results: The planning strategies had different impacts on bone marrow sparing for the cervical and prostate cases. For the cervical cases, provided the bone marrow constraints were properlymore » set during optimization, the dose to bone marrow sparing was found to be comparable between different IMRT and VMAT plans regardless of the gantry angle selection. For the prostate cases, however, careful selection of gantry angles could dramatically improve the bone marrow sparing, although the dose distribution in bone marrow was clinically acceptable for all prostate plans that we created. Conclusion: For intensity-modulated RDT planning for cervical cancer, planners should set bone marrow constraints properly to avoid any adverse damage, while for prostate cancer one can carefully select gantry angles to improve bone marrow sparing when necessary.« less

Authors:
 [1];  [2]; ; ;  [1]; ;  [3]
  1. Fox Chase Cancer Center, Philadelphia, PA (United States)
  2. (China)
  3. Renmin Hospital of Wuhan University, Wuhan, Hubei Province (China)
Publication Date:
OSTI Identifier:
22545148
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:
60 APPLIED LIFE SCIENCES; BONE MARROW; NEOPLASMS; PATIENTS; PROSTATE; RADIATION DOSE DISTRIBUTIONS; RADIATION DOSES; RADIOSENSITIVITY; RADIOTHERAPY; SENSITIZERS; SKELETON

Citation Formats

Li, C, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, Wang, B, Dong, Z, Ma, C, Ge, W, and Xu, L. SU-E-T-13: A Comparative Dosimetric Study On Radio-Dynamic Therapy for Pelvic Cancer Treatment: Strategies for Bone Marrow Dose and Volume Reduction. United States: N. p., 2015. Web. doi:10.1118/1.4924374.
Li, C, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, Wang, B, Dong, Z, Ma, C, Ge, W, & Xu, L. SU-E-T-13: A Comparative Dosimetric Study On Radio-Dynamic Therapy for Pelvic Cancer Treatment: Strategies for Bone Marrow Dose and Volume Reduction. United States. doi:10.1118/1.4924374.
Li, C, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, Wang, B, Dong, Z, Ma, C, Ge, W, and Xu, L. Mon . "SU-E-T-13: A Comparative Dosimetric Study On Radio-Dynamic Therapy for Pelvic Cancer Treatment: Strategies for Bone Marrow Dose and Volume Reduction". United States. doi:10.1118/1.4924374.
@article{osti_22545148,
title = {SU-E-T-13: A Comparative Dosimetric Study On Radio-Dynamic Therapy for Pelvic Cancer Treatment: Strategies for Bone Marrow Dose and Volume Reduction},
author = {Li, C and Renmin Hospital of Wuhan University, Wuhan, Hubei Province and Wang, B and Dong, Z and Ma, C and Ge, W and Xu, L},
abstractNote = {Purpose: Radio-dynamic therapy (RDT) is a potentially effective modality for local and systemic cancer treatment. Using RDT, the administration of a radio-sensitizer enhances the biological effect of high-energy photons. Although the sensitizer uptake ratio of tumor to normal tissue is normally high, one cannot simply neglect its effect on critical structures. In this study, we aim to explore planning strategies to improve bone marrow sparing without compromising the plan quality for RDT treatment of pelvic cancers. Methods: Ten cervical and ten prostate cancer patients who previously received radiotherapy at our institution were selected for this study. For each patient, nine plans were created using the Varian Eclipse treatmentplanning-system (TPS) with 3D-CRT, IMRT, and VMAT delivery techniques containing various gantry angle combinations and optimization parameters (dose constraints to the bone marrow). To evaluate the plans for bone marrow sparing, the dose-volume parameters V5, V10, V15, V20, V30, and V40 for bone marrow were examined. Effective doseenhancement factors for the sensitizer were used to weigh the dose-volume histograms for various tissues from individual fractions. Results: The planning strategies had different impacts on bone marrow sparing for the cervical and prostate cases. For the cervical cases, provided the bone marrow constraints were properly set during optimization, the dose to bone marrow sparing was found to be comparable between different IMRT and VMAT plans regardless of the gantry angle selection. For the prostate cases, however, careful selection of gantry angles could dramatically improve the bone marrow sparing, although the dose distribution in bone marrow was clinically acceptable for all prostate plans that we created. Conclusion: For intensity-modulated RDT planning for cervical cancer, planners should set bone marrow constraints properly to avoid any adverse damage, while for prostate cancer one can carefully select gantry angles to improve bone marrow sparing when necessary.},
doi = {10.1118/1.4924374},
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: RTOG 1005 requires density correction in the dose calculation of breast cancer radiation treatment. The aim of the study was to evaluate the impact of density correction on the dose calculation. Methods: Eight cases were studied, which were planned on an XiO treatment planning system with pixel-by-pixel density correction using a superposition algorithm, following RTOG 1005 protocol requirements. Four were protocol Arm 1 (standard whole breast irradiation with sequential boost) cases and four were Arm 2 (hypofractionated whole breast irradiation with concurrent boost) cases. The plans were recalculated with the same monitor units without density correction. Dose calculations withmore » and without density correction were compared. Results: Results of Arm 1 and Arm 2 cases showed similar trends in the comparison. The average differences between the calculations with and without density correction (difference = Without - With) among all the cases were: -0.82 Gy (range: -2.65∼−0.18 Gy) in breast PTV Eval D95, −0.75 Gy (range: −1.23∼0.26 Gy) in breast PTV Eval D90, −1.00 Gy (range: −2.46∼−0.29 Gy) in lumpectomy PTV Eval D95, −0.78 Gy (range: −1.30∼0.11 Gy) in lumpectomy PTV Eval D90, −0.43% (range: −0.95∼−0.14%) in ipsilateral lung V20, −0.81% (range: −1.62∼−0.26%) in V16, −1.95% (range: −4.13∼−0.84%) in V10, −2.64% (−5.55∼−1.04%) in V8, −4.19% (range: −6.92∼−1.81%) in V5, and −4.95% (range: −7.49∼−2.01%) in V4, respectively. The differences in other normal tissues were minimal. Conclusion: The effect of density correction was observed in breast target doses (an average increase of ∼1 Gy in D95 and D90, compared to the calculation without density correction) and exposed ipsilateral lung volumes in low dose region (average increases of ∼4% and ∼5% in V5 and V4, respectively)« less
  • Purpose: To estimate and compare the doses received by the obturator, external and internal iliac lymph nodes and point Methods: CT-MR fused image sets of 15 patients obtained for each of 5 fractions of HDR brachytherapy using tandem and ring applicator, were used to generate treatment plans optimized to deliver a prescription dose to HRCTV-D90 and to minimize the doses to organs at risk (OARs). For each set of image, target volume (GTV, HRCTV) OARs (Bladder, Rectum, Sigmoid), and both left and right pelvic lymph nodes (obturator, external and internal iliac lymph nodes) were delineated. Dose-volume histograms (DVH) were generatedmore » for pelvic nodal groups (left and right obturator group, internal and external iliac chains) Per fraction DVH parameters used for dose comparison included dose to 100% volume (D100), and dose received by 2cc (D2cc), 1cc (D1cc) and 0.1 cc (D0.1cc) of nodal volume. Dose to point B was compared with each DVH parameter using 2 sided t-test. Pearson correlation were determined to examine relationship of point B dose with nodal DVH parameters. Results: FIGO clinical stage varied from 1B1 to IIIB. The median pretreatment tumor diameter measured on MRI was 4.5 cm (2.7– 6.4cm).The median dose to bilateral point B was 1.20 Gy ± 0.12 or 20% of the prescription dose. The correlation coefficients were all <0.60 for all nodal DVH parameters indicating low degree of correlation. Only 2 cc of obturator nodes was not significantly different from point B dose on t-test. Conclusion: Dose to point B does not adequately represent the dose to any specific pelvic nodal group. When using image guided 3D dose-volume optimized treatment nodal groups should be individually identified and delineated to obtain the doses received by pelvic nodes.« less
  • Purpose: This study evaluates the dosimetric differences using volumetric modulated arc therapy (VMAT) in patients previously treated with intensity modulated radiation therapy IMRT for stereotactic body radiotherapy (SBRT) in early stage lung cancer. Methods: We evaluated 9 consecutive medically inoperable lung cancer patients at the start of the SBRT program who were treated with IMRT from November 2010 to October 2011. These patients were treated using 6 MV energy. The 9 cases were then re-planned with VMAT performed with arc therapy using 6 MV flattening filter free (FFF) energy with the same organs at risk (OARS) constraints. Data collected formore » the treatment plans included target coverage, beam on time, dose to OARS and gamma pass rate. Results: Five patients were T1N0 and four patients were T2N0 with all tumors less than 5 cm. The average GTV was 13.02 cm3 (0.83–40.87) and average PTV was 44.65 cm3 (14.06–118.08). The IMRT plans had a mean of 7.2 angles (6–9) and 5.4 minutes (3.6–11.1) per plan. The VMAT plans had a mean of 2.8 arcs (2–3) and 4.0 minutes (2.2–6.0) per plan. VMAT had slightly more target coverage than IMRT with average increase in D95 of 2.68% (1.24–5.73) and D99 of 3.65% (0.88–8.77). VMAT produced lower doses to all OARs. The largest reductions were in maximum doses to the spinal cord with an average reduction of 24.1%, esophagus with an average reduction of 22.1%, and lung with an average reduction in the V20 of 16.3% The mean gamma pass rate was 99.8% (99.2–100) at 3 mm and 3% for VMAT with comparable values for IMRT. Conclusion: These findings suggest that using VMAT for SBRT in early stage lung cancer is superior to IMRT in terms of dose coverage, OAR dose and a lower treatment delivery time with a similar gamma pass rate.« less
  • Purpose: To evaluate performance of three commercially available treatment planning systems for stereotactic body radiation therapy (SBRT) of lung cancer using the following algorithms: Boltzmann transport equation based algorithm (AcurosXB AXB), convolution based algorithm Anisotropic Analytic Algorithm (AAA); and Monte Carlo based algorithm (XVMC). Methods: A total of 10 patients with early stage non-small cell peripheral lung cancer were included. The initial clinical plans were generated using the XVMC based treatment planning system with a prescription of 54Gy in 3 fractions following RTOG0613 protocol. The plans were recalculated with the same beam parameters and monitor units using AAA and AXBmore » algorithms. A calculation grid size of 2mm was used for all algorithms. The dose distribution, conformity, and dosimetric parameters for the targets and organs at risk (OAR) are compared between the algorithms. Results: The average PTV volume was 19.6mL (range 4.2–47.2mL). The volume of PTV covered by the prescribed dose (PTV-V100) were 93.97±2.00%, 95.07±2.07% and 95.10±2.97% for XVMC, AXB and AAA algorithms, respectively. There was no significant difference in high dose conformity index; however, XVMC predicted slightly higher values (p=0.04) for the ratio of 50% prescription isodose volume to PTV (R50%). The percentage volume of total lungs receiving dose >20Gy (LungV20Gy) were 4.03±2.26%, 3.86±2.22% and 3.85±2.21% for XVMC, AXB and AAA algorithms. Examination of dose volume histograms (DVH) revealed small differences in targets and OARs for most patients. However, the AAA algorithm was found to predict considerable higher PTV coverage compared with AXB and XVMC algorithms in two cases. The dose difference was found to be primarily located at the periphery region of the target. Conclusion: For clinical SBRT lung treatment planning, the dosimetric differences between three commercially available algorithms are generally small except at target periphery. XVMC and AXB algorithms are recommended for accurate dose estimation at tissue boundaries.« less
  • Purpose: In prostate proton radiotherapy, three fiducial markers are used for patient daily alignment. However fiducial alignment can change beamline heterogeneity in proton therapy. The purpose of this study is to determine the difference in fiducial and boney anatomy alignment for patient treatment. Methods and materials: Prostate cancer patients who received proton treatment were included in this study. 3 fiducial markers were implanted before the initial CT. All the patients were re-CT’d every 2 weeks to check the fiducial marker position reproducibility as well as dosimetric consistence of target coverage. In geometry study, re-CT were fused to the initial CTmore » base on the boney anatomy and the average fiducial marker displacement was measured the centers of the fiducials. Dosimetrically, the initial plan was recalculated directly to re-CT image set based on the boney alignment and fiducial alignment to determine the difference from daily treatment. Prostate coverage and hotspots were evaluated using the dose to 98% of the CTV (D98) and dose to 2% (D2), respectively. Results: The shift from the initial 6 patient CT image sets resulted in an average change in the fiducial location of 5.70 +/− 3 mm. Dosimetric comparison from a single patient revealed that differences from the planned dose resulted from both boney and fiducial alignment. Planned clinical treatment volume coverage resulted in a D98 of 70.44Gy and D2 of 70.84Gy compared to a D98 of 70.13Gy and D2 70.94Gy for boney alignment and a D98 of 70.08Gy and D2 71.18Gy for fiducial alignment respectively. Conclusion: This study demonstrates that with boney anatomy alignment there is little change to CTV coverage and only slightly worse CTV coverage and hotspot production with fiducial alignment. An increase patient cohort and further investigation is necessary to determine the whether boney alignment can help better control dose heterogeneity.« less