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Silveira ALFD, Araújo FDSG, Calheiro DS, Tavares E Silva AL, Rodrigues Gonçalves B, Souza Castro ALD, Nolasco AV, Meira-Belo LC. Evaluating the effect of low-density inhomogeneities: A comparative study of lithium fluoride detectors, radiochromic films, and collapsed cone algorithm in 6 MV photon beams. Appl Radiat Isot 2023; 202:111032. [PMID: 37801996 DOI: 10.1016/j.apradiso.2023.111032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 08/25/2023] [Accepted: 09/12/2023] [Indexed: 10/08/2023]
Abstract
In recent years, there has been significant advancement in the development of physical simulators for dose evaluation. Many dosimetric studies employ solid materials, equivalent to human tissues, to evaluate dose distribution. This study aims to evaluate the effectiveness of inhomogeneity correction carried out by the Monaco/Elekta radiotherapy planning software. To achieve this goal, a physical simulator was created using cork boards to simulate lung tissue and solid water to represent other tissues. This simulator was combined with a dosimetric system that utilized lithium fluoride thermoluminescent detectors - RADOS MTS-N (LiF:Mg,Ti). The thermoluminescent detectors were positioned at various depths using a precisely drilled 2.0 mm thick acrylic plate, and they were placed at predefined positions. The irradiation of the simulator was conducted using an Elekta Synergy® Platform accelerator, employing a 6 MV photon beam with a field size of 15 × 15 cm2 and a source-surface distance (SSD) of 97.5 cm. A radiation dose of 200 cGy was applied for this study. In addition to the dosimetric assessment using thermoluminescent detectors, GAFCHROMIC™ EBT-3 Dosimetry Films were utilized to evaluate the dose at the same measurement points. The dose distribution data measured with the detectors were compared with the values provided by the planning system (TPS) and the inhomogeneity correction was verified. The results support the hypothesis that there is a lack of precision in the analytical simulations performed by the TPS, particularly in cases involving dose distribution at interfaces with varying densities.
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Affiliation(s)
- Anna Luiza Fraga da Silveira
- Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, MG, Brazil; Instituto de Radioterapia São Francisco, Belo Horizonte, MG, Brazil.
| | - Fernanda da Silva Gonçalves Araújo
- Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, MG, Brazil; Radiocare - Centro Especializado em Radioterapia, Belo Horizonte, MG, Brazil
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Storey CL, Hanna GG, Greystoke A. Practical implications to contemplate when considering radical therapy for stage III non-small-cell lung cancer. Br J Cancer 2020; 123:28-35. [PMID: 33293673 PMCID: PMC7735214 DOI: 10.1038/s41416-020-01072-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The type of patients with stage III non-small-cell lung cancer (NSCLC) selected for concurrent chemoradiotherapy (cCRT) varies between and within countries, with higher-volume centres treating patients with more co-morbidities and higher-stage disease. However, in spite of these disease characteristics, these patients have improved overall survival, suggesting that there are additional approaches that should be optimised and potentially standardised. This paper aims to review the current knowledge and best practices surrounding treatment for patients eligible for cCRT. Initially, this includes timely acquisition of the full diagnostic workup for the multidisciplinary team to comprehensively assess a patient for treatment, as well as imaging scans, patient history, lung function and genetic tests. Such information can provide prognostic information on how a patient will tolerate their cCRT regimen, and to perhaps limit the use of additional supportive care, such as steroids, which could impact on further treatments, such as immunotherapy. Furthermore, knowledge of the safety profile of individual double-platinum chemotherapy regimens and the technological advances in radiotherapy could aid in optimising patients for cCRT treatment, improving its efficacy whilst minimising its toxicities. Finally, providing patients with preparatory and ongoing support with input from dieticians, palliative care professionals, respiratory and care-of-the-elderly physicians during treatment may also help in more effective treatment delivery, allowing patients to achieve the maximum potential from their treatments.
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Affiliation(s)
- Claire L Storey
- Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Gerard G Hanna
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia
| | - Alastair Greystoke
- Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK.
- Newcastle University Centre for Cancer, Newcastle University, Newcastle upon Tyne, UK.
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Ueda Y, Takakura T, Ota S, Kito S, Sasaki K, Shimizu H, Tatsumi D, Yano S, Nakamura M. Questionnaire survey on treatment planning techniques for lung stereotactic body radiotherapy in Japan. JOURNAL OF RADIATION RESEARCH 2020; 61:104-116. [PMID: 31845998 PMCID: PMC6977596 DOI: 10.1093/jrr/rrz081] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 06/07/2019] [Accepted: 11/25/2019] [Indexed: 06/10/2023]
Abstract
This study aimed to obtain details regarding treatment planning techniques for lung stereotactic body radiation therapy (SBRT) employed at each institution in Japan by using a questionnaire survey. An Internet questionnaire survey on SBRT procedures performed in 2016 was conducted by the QA/QC committee of the Japan Society of Medical Physics from April to June 2017. The questionnaire assessed two aspects: the environment for SBRT at each institution and the treatment planning techniques with and without respiratory motion management techniques (RMMT). Of the 309 evaluated responses, 218 institutions had performed SBRT. A total of 186 institutions performed SBRT without RMMT and 139 institutions performed SBRT with RMMT. When respiratory motion was ≥10 mm, 69 institutions applied RMMT. The leading RMMT were breath holding (77 institutions), respiratory gating (49 institutions) and real-time tumor tracking (11 institutions). The most frequently used irradiation technique was 3D conformal radiotherapy, which was used in 145 institutions without RMMT and 119 institutions with RMMT. Computed tomography (CT) images acquired under free breathing were mostly used for dose calculation for patients treated without RMMT. The usage ratio of IMRT/VMAT to SBRT is low in Japan, compared to elsewhere in the world (<20% vs ≥70%). Among the available dose calculation algorithms, superposition convolution was the most frequently used regardless of RMMT; however, 2% of institutions have not yet made heterogeneity corrections. In the prescription setting, about half of the institutions applied point prescriptions. The survey results revealed the most frequently used conditions, which may facilitate standardization of treatment techniques in lung SBRT.
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Affiliation(s)
- Yoshihiro Ueda
- Department of Radiation Oncology, Osaka International Cancer Institute, 3-1-69 Otemae, Chuo-ku, Osaka-shi, Osaka 541-8567, Japan
| | - Toru Takakura
- Department of Radiation Therapy, Uji-Tokushukai Medical Center, 145 Ishibashi, Makishima-cho, Uji-shi, Kyoto 611-0041, Japan
| | - Seiichi Ota
- Division of Radiological Technology, Department of Medical Technology, University Hospital, Kyoto Prefectural University of Medicine, 465 Kajiicho, Kawaramachi, Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan
| | - Satoshi Kito
- Department of Radiation Oncology, Tokyo Metropolitan Cancer and Infectious Disease Center Komagome Hospital, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8677, Japan
| | - Koji Sasaki
- Department of Radiation Therapy Education and Research, Graduate School of Radiological Technology, Gunma Prefectural College of Health Sciences, 323-1 Kamiokimachi, Maebashi-shi, Gunma 371-0052, Japan
| | - Hidetoshi Shimizu
- Department of Radiation Oncology, Aichi Cancer Center Hospital, 1-1 Kanokoden, Chikusa-Ku, Nagoya, Aichi 464-8681, Japan
| | - Daisaku Tatsumi
- Miyakojima IGRT Clinic, 1-16-22, Miyakojimahondori, Miyakojima-ku, Osaka 534-0021, Japan
| | - Shinsuke Yano
- Division of Clinical Radiology Service, Kyoto University Hospital, 54 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Mitsuhiro Nakamura
- Division of Medical Physics, Department of Information Technology and Medical Engineering, Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
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Chaikh A, Balosso J. Statistic and dosimetric criteria to assess the shift of the prescribed dose for lung radiotherapy plans when integrating point kernel models in medical physics: are we ready? Transl Lung Cancer Res 2017; 5:681-687. [PMID: 28149762 DOI: 10.21037/tlcr.2016.11.03] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND To apply the statistical bootstrap analysis and dosimetric criteria's to assess the change of prescribed dose (PD) for lung cancer to maintain the same clinical results when using new generations of dose calculation algorithms. METHODS Nine lung cancer cases were studied. For each patient, three treatment plans were generated using exactly the same beams arrangements. In plan 1, the dose was calculated using pencil beam convolution (PBC) algorithm turning on heterogeneity correction with modified batho (PBC-MB). In plan 2, the dose was calculated using anisotropic analytical algorithm (AAA) and the same PD, as plan 1. In plan 3, the dose was calculated using AAA with monitor units (MUs) obtained from PBC-MB, as input. The dosimetric criteria's include MUs, delivered dose at isocentre (Diso) and calculated dose to 95% of the target volume (D95). The bootstrap method was used to assess the significance of the dose differences and to accurately estimate the 95% confidence interval (95% CI). Wilcoxon and Spearman's rank tests were used to calculate P values and the correlation coefficient (ρ). RESULTS Statistically significant for dose difference was found using point kernel model. A good correlation was observed between both algorithms types, with ρ>0.9. Using AAA instead of PBC-MB, an adjustment of the PD in the isocentre is suggested. CONCLUSIONS For a given set of patients, we assessed the need to readjust the PD for lung cancer using dosimetric indices and bootstrap statistical method. Thus, if the goal is to keep on with the same clinical results, the PD for lung tumors has to be adjusted with AAA. According to our simulation we suggest to readjust the PD by 5% and an optimization for beam arrangements to better protect the organs at risks (OARs).
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Affiliation(s)
- Abdulhamid Chaikh
- Department of Radiation Oncology and Medical Physics, University Hospital of Grenoble (CHU-GA), Grenoble, France; ; France HADRON National Research Infrastructure, IPNL, Lyon, France
| | - Jacques Balosso
- Department of Radiation Oncology and Medical Physics, University Hospital of Grenoble (CHU-GA), Grenoble, France; ; France HADRON National Research Infrastructure, IPNL, Lyon, France; ; Department of Radiation Oncology and Medical Physics, University Grenoble, Alpes, Grenoble, France
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DART-bid for loco-regionally advanced NSCLC : Summary of acute and late toxicity with long-term follow-up; experiences with pulmonary dose constraints. Strahlenther Onkol 2017; 193:315-323. [PMID: 28116446 PMCID: PMC5360836 DOI: 10.1007/s00066-016-1095-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 12/22/2016] [Indexed: 12/19/2022]
Abstract
Background To report acute and late toxicity with long-term follow-up, and to describe our experiences with pulmonary dose constraints. Methods Between 2002 and 2009, 150 patients with 155 histologically/cytologically proven non-small cell lung cancer (NSCLC; tumor stages II, IIIA, IIIB in 6, 55 and 39%, respectively) received the following median doses: primary tumors 79.2 Gy (range 72.0–90.0 Gy), lymph node metastases 59.4 Gy (54.0–73.8 Gy), nodes electively 45 Gy; with fractional doses of 1.8 Gy twice daily (bid). In all, 86% of patients received 2 cycles of chemotherapy previously. Results Five treatment-related deaths occurred: pneumonitis, n = 1; progressive pulmonary fibrosis in patients with pre-existing pulmonary fibrosis, n = 2; haemorrhage, n = 2. In all, 8% of patients experienced grade 3 and 1.3% grade 4 pneumonitis; 11% showed late fibrotic alterations grade 2 in lung parenchyma. Clinically relevant acute esophagitis (grade 2 and 3) was seen in 33.3% of patients, 2 patients developed late esophageal stenosis (G3). Patients with upper lobe, middle lobe and central lower lobe tumours (n = 130) were treated with V20 (total lung) up to 50% and patients with peripheral lower lobe tumours (n = 14, basal lateral tumours excluded) up to 42%, without observing acute or late pulmonary toxicity >grade 3. Only patients with basal lateral lower lobe tumours (n = 5) experienced grade 4/5 pulmonary toxicity; V20 for this latter group ranged between 30 and 53%. The mean lung dose was below the QUANTEC recommendation of 20–23 Gy in all patients. The median follow-up time of all patients is 26.3 months (range 2.9–149.4) and of patients alive 80.2 months (range 63.9–149.4.). The median overall survival time of all patients is 26.3 months; the 2-, 5- and 8‑year survival rates of 54, 21 and 15%, respectively. The local tumour control rate at 2 and 5 years is 70 and 64%, the regional control rate 90 and 88%, respectively. Discussion and conclusion Grade 4 or 5 toxicity occurred in 7/150 patients (4.7%), which can be partially avoided in the future (e.g. by excluding patients with pre-existing pulmonary fibrosis). Tolerance and oncologic outcome compare favourably to concomitant chemoradiation also in long-term follow-up.
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Das IJ, Cheng CW, Cao M, Johnstone PAS. Computed tomography imaging parameters for inhomogeneity correction in radiation treatment planning. J Med Phys 2016; 41:3-11. [PMID: 27051164 PMCID: PMC4795414 DOI: 10.4103/0971-6203.177277] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Modern treatment planning systems provide accurate dosimetry in heterogeneous media (such as a patient' body) with the help of tissue characterization based on computed tomography (CT) number. However, CT number depends on the type of scanner, tube voltage, field of view (FOV), reconstruction algorithm including artifact reduction and processing filters. The impact of these parameters on CT to electron density (ED) conversion had been subject of investigation for treatment planning in various clinical situations. This is usually performed with a tissue characterization phantom with various density plugs acquired with different tube voltages (kilovoltage peak), FOV reconstruction and different scanners to generate CT number to ED tables. This article provides an overview of inhomogeneity correction in the context of CT scanning and a new evaluation tool, difference volume dose-volume histogram (DVH), dV-DVH. It has been concluded that scanner and CT parameters are important for tissue characterizations, but changes in ED are minimal and only pronounced for higher density materials. For lungs, changes in CT number are minimal among scanners and CT parameters. Dosimetric differences for lung and prostate cases are usually insignificant (<2%) in three-dimensional conformal radiation therapy and < 5% for intensity-modulated radiation therapy (IMRT) with CT parameters. It could be concluded that CT number variability is dependent on acquisition parameters, but its dosimetric impact is pronounced only in high-density media and possibly in IMRT. In view of such small dosimetric changes in low-density medium, the acquisition of additional CT data for financially difficult clinics and countries may not be warranted.
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Affiliation(s)
- Indra J Das
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Chee-Wai Cheng
- Department of Radiation Oncology, University Hospitals Case Medical Center, Cleveland, OH 44255, USA
| | - Minsong Cao
- Department of Radiation Oncology, University of California- Los Angeles School of Medicine, CA 90095, USA
| | - Peter A S Johnstone
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL 33612, USA
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Chaikh A, Giraud JY, Marguet M, Silva D, Perrin E, Balosso J. A decision tool to adjust the prescribed dose after change in the dose calculation algorithm. INTERNATIONAL JOURNAL OF CANCER THERAPY AND ONCOLOGY 2014. [DOI: 10.14319/ijcto.0204.14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Cilla S, Digesù C, Macchia G, Deodato F, Sallustio G, Piermattei A, Morganti A. Clinical implications of different calculation algorithms in breast radiotherapy: A comparison between pencil beam and collapsed cone convolution. Phys Med 2014; 30:473-81. [DOI: 10.1016/j.ejmp.2014.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 01/09/2014] [Accepted: 01/11/2014] [Indexed: 11/30/2022] Open
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Chaikh A, Giraud JY, Balosso J. A method to quantify and assess the dosimetric and clinical impact resulting from the heterogeneity correction in radiotherapy for lung cancer. INTERNATIONAL JOURNAL OF CANCER THERAPY AND ONCOLOGY 2014. [DOI: 10.14319/ijcto.0201.10] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Chetty IJ, Devpura S, Liu D, Chen D, Li H, Wen NW, Kumar S, Fraser C, Siddiqui MS, Ajlouni M, Movsas B. Correlation of dose computed using different algorithms with local control following stereotactic ablative radiotherapy (SABR)-based treatment of non-small-cell lung cancer. Radiother Oncol 2013; 109:498-504. [PMID: 24231237 DOI: 10.1016/j.radonc.2013.10.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 10/02/2013] [Accepted: 10/03/2013] [Indexed: 02/06/2023]
Abstract
PURPOSE To retrospectively compute dose distributions for lung cancer patients treated with SABR, and to correlate dose distributions with outcome using a tumor control probability (TCP) model. METHODS Treatment plans for 133 NSCLC patients treated using 12 Gy/fxn × 4 (BED=106 Gy), and planned using a pencil-beam (1D-equivalent-path-length, EPL-1D) algorithm were retrospectively re-calculated using model-based algorithms (including convolution/superposition, Monte Carlo). 4D imaging was performed to manage motion. TCP was computed using the Marsden model and associations between dose and outcome were inferred. RESULTS Mean D95 reductions of 20% (max.=33%) were noted with model-based algorithms (relative to EPL-1D) for the smallest tumors (PTV<20 cm(3)), corresponding to actual delivered D95 BEDs of ≈ 60-85 Gy. For larger tumors (PTV>100 cm(3)), D95 reductions were ≈ 10% (BED>100 Gy). Mean lung doses (MLDs) were 15% lower for model-based algorithms for PTVs<20 cm(3). No correlation between tumor size and 2-year local control rate was observed clinically, consistent with TCP calculations, both of which were ≈ 90% across all PTV bins. CONCLUSION Results suggest that similar control rates might be achieved for smaller tumors using lower BEDs relative to larger tumors. However, more studies with larger patient cohorts are necessary to confirm this possible finding.
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Affiliation(s)
- Indrin J Chetty
- Department of Radiation Oncology, Henry Ford Hospital, Detroit, USA.
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Altunbas C, Kavanagh B, Dzingle W, Stuhr K, Gaspar L, Miften M. Dosimetric errors during treatment of centrally located lung tumors with stereotactic body radiation therapy: Monte Carlo evaluation of tissue inhomogeneity corrections. Med Dosim 2013; 38:436-41. [PMID: 24119416 DOI: 10.1016/j.meddos.2013.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 11/30/2012] [Accepted: 06/05/2013] [Indexed: 10/26/2022]
Abstract
Early experience with stereotactic body radiation therapy (SBRT) of centrally located lung tumors indicated increased rate of high-grade toxicity in the lungs. These clinical results were based on treatment plans that were computed using pencil beam-like algorithms and without tissue inhomogeneity corrections. In this study, we evaluated the dosimetric errors in plans with and without inhomogeneity corrections and with planning target volumes (PTVs) that were within the zone of the proximal bronchial tree (BT). For 10 patients, the PTV, lungs, and sections of the BT either inside or within 2cm of the PTV were delineated. Two treatment plans were generated for each patient using the following dose-calculation methods: (1) pencil beam (PB) algorithm without inhomogeneity correction (IC) (PB - IC) and (2) PB with inhomogeneity correction (PB + IC). Both plans had identical beam geometry but different beam segment shapes and monitor units (MU) to achieve similar conformal dose coverage of PTV. To obtain the baseline dose distributions, each plan was recalculated using a Monte Carlo (MC) algorithm by keeping MUs the same in the respective plans. The median maximum dose to the proximal BT and PTV dose coverage in the PB + IC plans were overestimated by 8% and 11%, respectively. However, the median maximum dose to the proximal BT and PTV dose coverage in PB - IC plans were underestimated by 15% and 9%. Similar trends were observed in low-dose regions of the lung within the irradiated volume. Our study indicates that dosimetric bias introduced by unit tissue density plans cannot be characterized as underestimation or overestimation of dose without taking the tumor location into account. This issue should be considered when analyzing clinical toxicity data from early lung SBRT trials that utilized unit tissue density for dose calculations.
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Affiliation(s)
- Cem Altunbas
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, CO.
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Bufacchi A, Nardiello B, Capparella R, Begnozzi L. Clinical implications in the use of the PBC algorithm versus the AAA by comparison of different NTCP models/parameters. Radiat Oncol 2013; 8:164. [PMID: 23826854 PMCID: PMC3750611 DOI: 10.1186/1748-717x-8-164] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Accepted: 06/13/2013] [Indexed: 12/25/2022] Open
Abstract
Purpose Retrospective analysis of 3D clinical treatment plans to investigate qualitative, possible, clinical consequences of the use of PBC versus AAA. Methods The 3D dose distributions of 80 treatment plans at four different tumour sites, produced using PBC algorithm, were recalculated using AAA and the same number of monitor units provided by PBC and clinically delivered to each patient; the consequences of the difference on the dose-effect relations for normal tissue injury were studied by comparing different NTCP model/parameters extracted from a review of published studies. In this study the AAA dose calculation is considered as benchmark data. The paired Student t-test was used for statistical comparison of all results obtained from the use of the two algorithms. Results In the prostate plans, the AAA predicted lower NTCP value (NTCPAAA) for the risk of late rectal bleeding for each of the seven combinations of NTCP parameters, the maximum mean decrease was 2.2%. In the head-and-neck treatments, each combination of parameters used for the risk of xerostemia from irradiation of the parotid glands involved lower NTCPAAA, that varied from 12.8% (sd=3.0%) to 57.5% (sd=4.0%), while when the PBC algorithm was used the NTCPPBC’s ranging was from 15.2% (sd=2.7%) to 63.8% (sd=3.8%), according the combination of parameters used; the differences were statistically significant. Also NTCPAAA regarding the risk of radiation pneumonitis in the lung treatments was found to be lower than NTCPPBC for each of the eight sets of NTCP parameters; the maximum mean decrease was 4.5%. A mean increase of 4.3% was found when the NTCPAAA was calculated by the parameters evaluated from dose distribution calculated by a convolution-superposition (CS) algorithm. A markedly different pattern was observed for the risk relating to the development of pneumonitis following breast treatments: the AAA predicted higher NTCP value. The mean NTCPAAA varied from 0.2% (sd = 0.1%) to 2.1% (sd = 0.3%), while the mean NTCPPBC varied from 0.1% (sd = 0.0%) to 1.8% (sd = 0.2%) depending on the chosen parameters set. Conclusions When the original PBC treatment plans were recalculated using AAA with the same number of monitor units provided by PBC, the NTCPAAA was lower than the NTCPPBC, except for the breast treatments. The NTCP is strongly affected by the wide-ranging values of radiobiological parameters.
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Affiliation(s)
- Antonella Bufacchi
- Medical Physics, PioXI Clinic and UOC Medical Physics, S Giovanni Calibita Fatebenefratelli Hospital, Rome, Italy.
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Thwaites D. Accuracy required and achievable in radiotherapy dosimetry: have modern technology and techniques changed our views? ACTA ACUST UNITED AC 2013. [DOI: 10.1088/1742-6596/444/1/012006] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Asnaashari K, Nodehi MRG, Mahdavi SR, Gholami S, Khosravi HR. Dosimetric comparison of different inhomogeneity correction algorithms for external photon beam dose calculations. J Med Phys 2013; 38:74-81. [PMID: 23776310 PMCID: PMC3683304 DOI: 10.4103/0971-6203.111310] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 02/13/2013] [Accepted: 02/13/2013] [Indexed: 11/23/2022] Open
Abstract
Dose calculation algorithm is one of the main sources of uncertainty in the radiotherapy sequences. The aim of this study was to compare the accuracy of different inhomogeneity correction algorithms for external photon beam dose calculations. The methodology was based on International Atomic Energy Agency TEC-DOC 1583. The phantom was scanned in every center, using computed tomography and seven tests were planned on three-dimensional treatment planning systems (TPSs). The doses were measured with ion chambers and the deviation between measured and TPS calculated dose was reported. This methodology was tested in five different hospitals which were using six different algorithms/inhomogeneity correction methods implemented in different TPSs. The algorithms in this study were divided into two groups: Measurement-based algorithms (type (a)) and model-based algorithms (type (b)). In type (a) algorithms, we saw 7.6% and 11.3% deviations out of agreement criteria for low- and high-energy photons, respectively. While in type (b) algorithms, these values were 4.3% and 5.1%, respectively. As a general trend, the numbers of measurements with results outside the agreement criteria increase with the beam energy and decrease with advancement of TPS algorithms. More advanced algorithm would be preferable and therefore should be implanted in clinical practice, especially for calculation in inhomogeneous medias like lung and bone and for high-energy beams calculation at low depth points.
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Curtis H, Richmond N, Burke K, Walker C. Determination of monitor unit check tolerances based on a comparison with measurement and treatment planning system data. Med Dosim 2013; 38:81-7. [DOI: 10.1016/j.meddos.2012.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 07/09/2012] [Accepted: 07/30/2012] [Indexed: 10/27/2022]
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Dose correction in lung for HDR breast brachytherapy. J Contemp Brachytherapy 2013; 4:106-10. [PMID: 23349652 PMCID: PMC3552632 DOI: 10.5114/jcb.2012.29367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 05/16/2012] [Accepted: 06/06/2012] [Indexed: 11/17/2022] Open
Abstract
Purpose To evaluate the dosimetric impact of lung tissue in Ir-192 APBI. Material and methods In a 40 × 40 × 40 cm3 water tank, an Accelerated Partial Breast Irradiation (APBI) brachytherapy balloon inflated to 4 cm diameter was situated directly below the center of a 30 × 30 × 1 cm3 solid water slab. Nine cm of solid water was stacked above the 1 cm base. A parallel plate ion chamber was centered above the base and ionization current measurements were taken from the central HDR source dwell position for channels 1, 2, 3 and 5 of the balloon. Additional ionization data was acquired in the 9 cm stack at 1 cm increments. A comparable data set was also measured after replacing the 9 cm solid water stack with cork slabs. The ratios of measurements in the two phantoms were calculated and compared to predicted results of a commercial treatment planning system. Results Lower dose was measured in the cork within 1 cm of the cork/solid water interface possibly due to backscatter effects. Higher dose was measured beyond 1 cm from the cork/solid water interface, increasing with path length up to 15% at 9 cm depth in cork. The treatment planning system did not predict either dose effect. Conclusions This study investigates the dosimetry of low density material when the breast is treated with Ir-192 brachytherapy. HDR dose from Ir-192 in a cork media is shown to be significantly different than in unit density media. These dose differences are not predicted in most commercial brachytherapy planning systems. Empirical models based on measurements could be used to estimate lung dose associated with HDR breast brachytherapy.
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van Baardwijk A, Tomé WA, van Elmpt W, Bentzen SM, Reymen B, Wanders R, Houben R, Ollers M, Lambin P, De Ruysscher D. Is high-dose stereotactic body radiotherapy (SBRT) for stage I non-small cell lung cancer (NSCLC) overkill? A systematic review. Radiother Oncol 2012; 105:145-9. [PMID: 23068707 DOI: 10.1016/j.radonc.2012.09.008] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 08/18/2012] [Accepted: 09/06/2012] [Indexed: 12/25/2022]
Abstract
BACKGROUND AND PURPOSE For stereotactic body radiotherapy (SBRT), typically a scheme of 60 Gy in 3-8 fractions is applied, producing local tumour control rates around 90%. The dose specification is in one point only and ignores possible underdosages at the edge of the planning target volume (PTV). We investigated the doses at the edge of the PTV and correlated this with local tumour control with the aim to shed light on the radiation dose needed to eradicate stage I NSCLC. MATERIALS AND METHODS Published data on the freedom from local progression (FFLP) data from SBRT and accelerated high-dose conventional radiotherapy series for stage I NSCLC with a follow up of at least 30 months were included. The EQD(2,T) was calculated from the dose at the periphery of the PTV. RESULTS Fifteen studies for SBRT (1076 patients) showed a median FFLP of 88.0±10.4% with a median EQD(2,T) of 76.9±17.4 Gy. The median FFLP was 87.6±6.0% for the accelerated schedules with an EQD(2,T) of 86.9±39.1 Gy, respectively. No significant relation was found between FFLP and the EQD(2,T) (p=0.23). CONCLUSIONS Several fractionated and accelerated schedules with equal biological doses achieve the same tumour control rates as SBRT. Lower, but more uniform doses to the whole PTV may be sufficient to achieve similar control rates, with the possibility to deliver SBRT in adapted schedules, beneficial to centrally located tumours in the vicinity of critical structures like the oesophagus and great vessels.
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De Ruysscher D, Faivre-Finn C, Nestle U, Hurkmans CW, Le Péchoux C, Price A, Senan S. European Organisation for Research and Treatment of Cancer Recommendations for Planning and Delivery of High-Dose, High-Precision Radiotherapy for Lung Cancer. J Clin Oncol 2010; 28:5301-10. [DOI: 10.1200/jco.2010.30.3271] [Citation(s) in RCA: 203] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Purpose To derive recommendations for routine practice and clinical trials for techniques used in high-dose, high-precision thoracic radiotherapy for lung cancer. Methods A literature search was performed to identify published articles considered both clinically relevant and practical to use. Recommendations were categorized under the following headings: patient selection, patient positioning and immobilization, tumor motion, computed tomography and [18F]fluorodeoxyglucose–positron emission technology scanning, generating target volumes, radiotherapy treatment planning, treatment delivery, and scoring of response and toxicity. The American College of Chest Physicians grading of recommendations was used. Results Recommendations were identified for each of the recommendation categories. Although most of the recommended techniques have not been evaluated in multicenter clinical trials, their use in high-precision thoracic radiotherapy and stereotactic body radiotherapy (SBRT) appears to be justified on the basis of available evidence. Conclusion Recommendations to facilitate the clinical implementation of high-precision conformal radiotherapy and SBRT for lung tumors were identified from the literature. Some techniques that are considered investigational at present were also highlighted.
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Affiliation(s)
- Dirk De Ruysscher
- From the Maastricht University Medical Center, GROW Research Institute, Maastricht; Free University Medical Center, Amsterdam; and Catharina Hospital, Eindhoven, the Netherlands; the Christie, Manchester; and Edinburgh Cancer Centre, Western General Hospital, Edinburgh, United Kingdom; Freiburg University Medical Center, Freiburg, Germany; and Gustave Roussy Institute, Villejuif, France
| | - Corinne Faivre-Finn
- From the Maastricht University Medical Center, GROW Research Institute, Maastricht; Free University Medical Center, Amsterdam; and Catharina Hospital, Eindhoven, the Netherlands; the Christie, Manchester; and Edinburgh Cancer Centre, Western General Hospital, Edinburgh, United Kingdom; Freiburg University Medical Center, Freiburg, Germany; and Gustave Roussy Institute, Villejuif, France
| | - Ursula Nestle
- From the Maastricht University Medical Center, GROW Research Institute, Maastricht; Free University Medical Center, Amsterdam; and Catharina Hospital, Eindhoven, the Netherlands; the Christie, Manchester; and Edinburgh Cancer Centre, Western General Hospital, Edinburgh, United Kingdom; Freiburg University Medical Center, Freiburg, Germany; and Gustave Roussy Institute, Villejuif, France
| | - Coen W. Hurkmans
- From the Maastricht University Medical Center, GROW Research Institute, Maastricht; Free University Medical Center, Amsterdam; and Catharina Hospital, Eindhoven, the Netherlands; the Christie, Manchester; and Edinburgh Cancer Centre, Western General Hospital, Edinburgh, United Kingdom; Freiburg University Medical Center, Freiburg, Germany; and Gustave Roussy Institute, Villejuif, France
| | - Cécile Le Péchoux
- From the Maastricht University Medical Center, GROW Research Institute, Maastricht; Free University Medical Center, Amsterdam; and Catharina Hospital, Eindhoven, the Netherlands; the Christie, Manchester; and Edinburgh Cancer Centre, Western General Hospital, Edinburgh, United Kingdom; Freiburg University Medical Center, Freiburg, Germany; and Gustave Roussy Institute, Villejuif, France
| | - Allan Price
- From the Maastricht University Medical Center, GROW Research Institute, Maastricht; Free University Medical Center, Amsterdam; and Catharina Hospital, Eindhoven, the Netherlands; the Christie, Manchester; and Edinburgh Cancer Centre, Western General Hospital, Edinburgh, United Kingdom; Freiburg University Medical Center, Freiburg, Germany; and Gustave Roussy Institute, Villejuif, France
| | - Suresh Senan
- From the Maastricht University Medical Center, GROW Research Institute, Maastricht; Free University Medical Center, Amsterdam; and Catharina Hospital, Eindhoven, the Netherlands; the Christie, Manchester; and Edinburgh Cancer Centre, Western General Hospital, Edinburgh, United Kingdom; Freiburg University Medical Center, Freiburg, Germany; and Gustave Roussy Institute, Villejuif, France
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Kadoya N, Obata Y, Kato T, Kagiya M, Nakamura T, Tomoda T, Takada A, Takayama K, Fuwa N. Dose-volume comparison of proton radiotherapy and stereotactic body radiotherapy for non-small-cell lung cancer. Int J Radiat Oncol Biol Phys 2010; 79:1225-31. [PMID: 20732759 DOI: 10.1016/j.ijrobp.2010.05.016] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 05/09/2010] [Accepted: 05/12/2010] [Indexed: 12/25/2022]
Abstract
PURPOSE This study designed photon and proton treatment plans for patients treated with hypofractionated proton radiotherapy (PT) at the Southern Tohoku Proton Therapy Center (STPTC). We then calculated dosimetric parameters and compared results with simulated treatment plans for stereotactic body radiotherapy (SBRT), using dose--volume histograms to clearly explain differences in dose distributions between PT and SBRT. METHODS AND MATERIALS Twenty-one patients with stage I non-small-cell lung cancer (stage IA, n = 15 patients; stage IB, n = 6 patients) were studied. All tumors were located in the peripheral lung, and total dose was 66 Gray equivalents (GyE) (6.6 GyE/fraction). For treatment planning, beam incidence for proton beam technique was restricted to two to three directions for PT, and seven or eight noncoplanar beams were manually selected for SBRT to achieve optimal planning target volume (PTV) coverage and minimal dose to organs at risk. RESULTS Regarding lung tissues, mean dose, V5, V10, V13, V15, and V20 values were 4.6 Gy, 13.2%, 11.4%, 10.6%, 10.1%, and 9.1%, respectively, for PT, whereas those values were 7.8 Gy, 32.0%, 21.8%, 17.4%, 15.3%, and 11.4%, respectively, for SBRT with a prescribed dose of 66 Gy. Pearson product moment correlation coefficients between PTV and dose--volume parameters of V5, V10, V15, and V20 were 0.45, 0.52, 0.58, and 0.63, respectively, for PT, compared to 0.52, 0.45, 0.71, and 0.74, respectively, for SBRT. CONCLUSIONS Correlations between dose--volume parameters of the lung and PTV were observed and may indicate that PT is more advantageous than SBRT when treating a tumor with a relatively large PTV or several tumors.
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Affiliation(s)
- Noriyuki Kadoya
- Department of Medical Physics, Southern Tohoku Proton Therapy Center, Southern Tohoku Institute of Neuroscience, Koriyama, Fukushima, Japan.
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Buyyounouski MK, Balter P, Lewis B, D'Ambrosio DJ, Dilling TJ, Miller RC, Schefter T, Tomé W, Harris EER, Price RA, Konski AA, Wallner PE. Stereotactic body radiotherapy for early-stage non-small-cell lung cancer: report of the ASTRO Emerging Technology Committee. Int J Radiat Oncol Biol Phys 2010; 78:3-10. [PMID: 20643514 DOI: 10.1016/j.ijrobp.2010.04.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 04/02/2010] [Accepted: 04/02/2010] [Indexed: 12/25/2022]
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Thwaites DI, Verellen D. Vorsprung durch Technik: evolution, implementation, QA and safety of new technology in radiotherapy. Radiother Oncol 2010; 94:125-8. [PMID: 20170973 DOI: 10.1016/j.radonc.2010.02.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Accepted: 02/09/2010] [Indexed: 11/18/2022]
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The effect of planning algorithms in oesophageal radiotherapy in the context of the SCOPE 1 trial. Radiother Oncol 2009; 93:462-7. [DOI: 10.1016/j.radonc.2009.08.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 08/21/2009] [Accepted: 08/24/2009] [Indexed: 11/21/2022]
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Linac-based isocentric electron–photon treatment of radically operated breast carcinoma with enhanced dose uniformity in the field gap area. Radiother Oncol 2009; 93:80-6. [DOI: 10.1016/j.radonc.2009.04.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Revised: 04/11/2009] [Accepted: 04/16/2009] [Indexed: 11/22/2022]
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Baumann M, Zips D, Appold S. Radiotherapy of lung cancer: Technology meets biology meets multidisciplinarity. Radiother Oncol 2009; 91:279-81. [DOI: 10.1016/j.radonc.2009.05.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Accepted: 05/07/2009] [Indexed: 11/26/2022]
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Aarup LR, Nahum AE, Zacharatou C, Juhler-Nøttrup T, Knöös T, Nyström H, Specht L, Wieslander E, Korreman SS. The effect of different lung densities on the accuracy of various radiotherapy dose calculation methods: Implications for tumour coverage. Radiother Oncol 2009; 91:405-14. [PMID: 19297051 DOI: 10.1016/j.radonc.2009.01.008] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 01/22/2009] [Accepted: 01/24/2009] [Indexed: 11/27/2022]
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Pearson M, Atherton P, McMenemin R, McDonald F, Mazdai G, Mulvenna P, Lambert G. The Implementation of an Advanced Treatment Planning Algorithm in the Treatment of Lung Cancer with Conventional Radiotherapy. Clin Oncol (R Coll Radiol) 2009; 21:168-74. [DOI: 10.1016/j.clon.2008.11.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Revised: 10/20/2008] [Accepted: 11/20/2008] [Indexed: 10/21/2022]
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Transition from a simple to a more advanced dose calculation algorithm for radiotherapy of non-small cell lung cancer (NSCLC): Implications for clinical implementation in an individualized dose-escalation protocol. Radiother Oncol 2008; 88:326-34. [DOI: 10.1016/j.radonc.2008.07.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 06/26/2008] [Accepted: 07/06/2008] [Indexed: 11/23/2022]
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Cattaneo GM, Dell'oca I, Broggi S, Fiorino C, Perna L, Pasetti M, Sangalli G, di Muzio N, Fazio F, Calandrino R. Treatment planning comparison between conformal radiotherapy and helical tomotherapy in the case of locally advanced-stage NSCLC. Radiother Oncol 2008; 88:310-8. [PMID: 18692266 DOI: 10.1016/j.radonc.2008.06.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Revised: 06/11/2008] [Accepted: 06/19/2008] [Indexed: 10/21/2022]
Abstract
BACKGROUND AND PURPOSE To investigate the impact of Helical Tomotherapy (HT) upon the dose distribution when compared to our routinely delivered 3D conformal radiotherapy (CRT) in the case of patients affected by stage III non-small-cell lung cancer (NSCLC). MATERIAL AND METHODS Thirteen stage III inoperable NSCLC patients were scheduled to receive 61.2-70.2Gy, 1.8Gy/fraction. Two treatment techniques (HT and CRT) were considered, and in the case of CRT the dose calculation was performed using both the pencil beam (PB) and Anisotropic Analytical Algorithm (AAA) available on the Varian Eclipse planning system. Dose volume constraints for PTV coverage and OAR sparing were assessed for the HT inverse planning with the highest priority upon PTV coverage and spinal cord sparing. The three plans were compared in terms of dose-volume histograms (DVHs) and normal tissue complication probability (NTCP). A statistical analysis was performed using non-parametric Wilcoxon matched pairs tests. RESULTS In CRT the use of a less accurate algorithm (PB) decreased the monitor unit number by 2.4%. HT significantly improved dose homogeneity within PTV compared with CRT_AAA. For lung parenchyma V20-V40 were lower with HT, corresponding to a decrease of 7% in the risk of radiation pneumonitis. The volume of the heart and esophagus irradiated to >45-60Gy were reduced using HT plans. For eight PTs with an esophagus-PTV overlap >5%, HT significantly reduced both late and acute esophageal complication probability. CONCLUSIONS Our findings obtained in stage III NSCLC patients underline that HT guarantees an important sparing of lungs and esophagus, thus HT has the potential to improve therapeutic ratio, when compared with CRT, by means of dose escalation and/or combined treatment strategy. In CRT of locally advanced lung cancers, the use of a more advanced algorithm would give significantly better modeling of target dose and coverage.
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Georg D, Hillbrand M, Stock M, Dieckmann K, Pötter R. Can protons improve SBRT for lung lesions? Dosimetric considerations. Radiother Oncol 2008; 88:368-75. [PMID: 18405986 DOI: 10.1016/j.radonc.2008.03.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 03/05/2008] [Accepted: 03/06/2008] [Indexed: 10/22/2022]
Abstract
BACKGROUND AND PURPOSE The aim of the present study was to investigate potential dosimetric benefits of proton therapy for hypofractionated stereotactic body radiotherapy (SBRT). MATERIALS AND METHOD Twelve patients undergoing hypofractionated SBRT at the Medical University Vienna were selected. Passively scattered protons (PT) and intensity modulated proton therapy (IMPT) were evaluated against a conformal photon technique (3D-CRT), assuming a fractionation of 3x15Gy, prescribed to the 65% isodose. For all treatment techniques shallow breathing with abdominal compression (SB+AC) was compared with a deep inspiration breath hold technique (DIBH). Treatment planning was done with XiO (CMS, USA). Target conformity, dose-volume histograms (DVH) and various associated dosimetric parameters were considered for the planning target volume (PTV), lung, heart and esophagus. RESULTS For both breathing conditions conformity indices were very similar. They were between 0.75 and 0.78 for IMPT and 3D-CRT and around 0.55 for PT using 2-3 beams. Irrespective of treatment modality, DVHs for the ipsilateral lung were improved with the DIBH technique. For the PT technique, the 2Gy isodose (V2Gy) covered on average 7-9% less lung volume compared to 3D-CRT, for IMPT this reduction was more than 10%. Volumes covered the 4 and 6Gy isodoses were 2-4% smaller for IMPT, but very similar for PT and 3D-CRT. Both proton techniques achieved full sparing of the contralateral lung and superior sparing of the heart. Maximum doses to the heart and esophagus were on average around 3Gy for 3D-CRT and almost 0Gy for both proton techniques. For 3D-CRT average V2Gy values for the heart could be reduced from 64% in shallow breathing to 34% in DIBH. V2Gy for protons was negligible. CONCLUSIONS Only small dosimetric differences were found between photons and protons for SBRT of lung lesions. Whether these small dosimetric benefits translate in reduced side effects or have the potential to improve local control rates remains to be demonstrated in clinical studies.
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Affiliation(s)
- Dietmar Georg
- Department of Radiotherapy, Medical University Vienna/AKH Vienna, Vienna, Austria.
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