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Sample records for cancer intensity modulated

  1. Dosimetrically Triggered Adaptive Intensity Modulated Radiation Therapy for Cervical Cancer

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    Lim, Karen [Department of Radiation Oncology, Liverpool Hospital, Sydney (Australia); Stewart, James [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario (Canada); Kelly, Valerie [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Xie, Jason [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Brock, Kristy K. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Moseley, Joanne [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Cho, Young-Bin; Fyles, Anthony [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Lundin, Anna; Rehbinder, Henrik; Löf, Johan [RaySearch Laboratories AB, Stockholm (Sweden); Jaffray, David A. [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada); Techna Institute for the Advancement of Technology for Health, Toronto, Ontario (Canada); Milosevic, Michael, E-mail: mike.milosevic@rmp.uhn.ca [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada)

    2014-09-01

    Purpose: The widespread use of intensity modulated radiation therapy (IMRT) for cervical cancer has been limited by internal target and normal tissue motion. Such motion increases the risk of underdosing the target, especially as planning margins are reduced in an effort to reduce toxicity. This study explored 2 adaptive strategies to mitigate this risk and proposes a new, automated method that minimizes replanning workload. Methods and Materials: Thirty patients with cervical cancer participated in a prospective clinical study and underwent pretreatment and weekly magnetic resonance (MR) scans over a 5-week course of daily external beam radiation therapy. Target volumes and organs at risk (OARs) were contoured on each of the scans. Deformable image registration was used to model the accumulated dose (the real dose delivered to the target and OARs) for 2 adaptive replanning scenarios that assumed a very small PTV margin of only 3 mm to account for setup and internal interfractional motion: (1) a preprogrammed, anatomy-driven midtreatment replan (A-IMRT); and (2) a dosimetry-triggered replan driven by target dose accumulation over time (D-IMRT). Results: Across all 30 patients, clinically relevant target dose thresholds failed for 8 patients (27%) if 3-mm margins were used without replanning. A-IMRT failed in only 3 patients and also yielded an additional small reduction in OAR doses at the cost of 30 replans. D-IMRT assured adequate target coverage in all patients, with only 23 replans in 16 patients. Conclusions: A novel, dosimetry-triggered adaptive IMRT strategy for patients with cervical cancer can minimize the risk of target underdosing in the setting of very small margins and substantial interfractional motion while minimizing programmatic workload and cost.

  2. Intensity modulated radiation therapy for breast cancer: current perspectives

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    Buwenge, Milly; Cammelli, Silvia; Ammendolia, Ilario; Tolento, Giorgio; Zamagni, Alice; Arcelli, Alessandra; Macchia, Gabriella; Deodato, Francesco; Cilla, Savino; Morganti, Alessio G

    2017-01-01

    Background Owing to highly conformed dose distribution, intensity modulated radiation therapy (IMRT) has the potential to improve treatment results of radiotherapy (RT). Postoperative RT is a standard adjuvant treatment in conservative treatment of breast cancer (BC). The aim of this review is to analyze available evidence from randomized controlled trials (RCTs) on IMRT in BC, particularly in terms of reduction of side effects. Methods A literature search of the bibliographic database PubMed, from January 1990 through November 2016, was performed. Only RCTs published in English were included. Results Ten articles reporting data from 5 RCTs fulfilled the selection criteria and were included in our review. Three out of 5 studies enrolled only selected patients in terms of increased risk of toxicity. Three studies compared IMRT with standard tangential RT. One study compared the results of IMRT in the supine versus the prone position, and one study compared standard treatment with accelerated partial breast IMRT. Three studies reported reduced acute and/or late toxicity using IMRT compared with standard RT. No study reported improved quality of life. Conclusion IMRT seems able to reduce toxicity in selected patients treated with postoperative RT for BC. Further analyses are needed to better define patients who are candidates for this treatment modality. PMID:28293119

  3. Intensity modulated radiotherapy versus volumetric modulated arc therapy in breast cancer: A comparative dosimetric analysis

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    KR Muralidhar

    2015-01-01

    Full Text Available Purpose: Intensity modulated radiotherapy (IMRT and volumetric modulated arc therapy (VMAT has the capacity to optimize the dose distribution. We analyzed the dosimetric differences of plans in treatment planning system (TPS between VMAT and IMRT in treating breast cancer. Methods: Fourteen patients were simulated, planned, and treated with VMAT using single, double or partial arcs. IMRT treatments were generated using 4 to 5 tangential IMRT fields for the same patients. All treatment plans were planned for 50 Gy in 25 fractions. The VMAT and IMRT plans were compared using the planning target volume (PTV dose and doses to the other organs at risk (OARs. Results: For the PTV, comparable minimum, mean, maximum, median, and modal dose as well equivalent sphere diameter of the structure (Equis were observed between VMAT and IMRT plans and found that these values were significantly equal in both techniques. The right lung mean and modal doses were considerably higher in VMAT plans while maximum value was considerably lower when compared with IMRT plans. The left lung mean and modal doses were higher with VMAT while maximum doses were higher in IMRT plans. The mean dose to the heart and maximum dose to the spinal cord was lower with IMRT. The mean dose to the body was higher in VMAT plans while the maximum dose was higher in IMRT plans. Conclusion: Four field tangential IMRT delivered comparable PTV dose with generally less dose to normal tissues in our breast cancer treatment study. The IMRT plans typically had more favourable dose characteristics to the lung, heart, and spinal cord and body dose when compared with VMAT. The only minor advantage of VMAT for breast cases was slightly better PTV coverage.

  4. Volumetric intensity modulated arc therapy in lung cancer: Current literature review

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    Suresh B Rana

    2013-01-01

    Full Text Available The volumetric intensity modulated arc therapy (VMAT is a novel radiation technique that delivers a highly conformal radiation dose to the target by allowing the simultaneous variation of gantry rotation speed, dose rate and multiple-leaf collimators leaf positions. The aim of this study was to review the current literature on two VMAT systems, RapidArc and SmartArc with main focus on planning studies of lung cancer. A systematic review of available data was conducted using MEDLINE/PubMed with the keywords ′′lung′′ and "VMAT". The published data show that VMAT techniques have clear superiority over three-dimensional conformal radiation therapy with regard to improving dose conformity and sparing of organs at risks (OARs. The data indicates that for lung tumor VMAT and intensity modulated radiation therapy (IMRT provide equivalent dose homogeneity, dose conformity and target volume coverage; however, contradictory results were obtained in terms of OARs sparing. The major advantages of VMAT over IMRT are the reduction in the number of monitor units and faster treatment delivery times without compromising the quality of the treatment plans. Moreover, faster delivery time is more patient-friendly and it minimizes intra-fractional patient motion allowing treatment volumes stay within their respective treatment margins. Current literature data shows that VMAT can be a good option to treat lung cancer; however, data on clinical trials are still lacking. The clinical trials are essential to confirm the safety and efficacy of VMAT techniques.

  5. Cardiac Exposure in the Dynamic Conformal Arc Therapy, Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy of Lung Cancer.

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    Xin Ming

    Full Text Available To retrospectively evaluate the cardiac exposure in three cohorts of lung cancer patients treated with dynamic conformal arc therapy (DCAT, intensity-modulated radiotherapy (IMRT, or volumetric modulated arc therapy (VMAT at our institution in the past seven years.A total of 140 lung cancer patients were included in this institutional review board approved study: 25 treated with DCAT, 70 with IMRT and 45 with VMAT. All plans were generated in a same commercial treatment planning system and have been clinically accepted and delivered. The dose distribution to the heart and the effects of tumor laterality, the irradiated heart volume and the beam-to-heart distance on the cardiac exposure were investigated.The mean dose to the heart among all 140 plans was 4.5 Gy. Specifically, the heart received on average 2.3, 5.2 and 4.6 Gy in the DCAT, IMRT and VMAT plans, respectively. The mean heart doses for the left and right lung tumors were 4.1 and 4.8 Gy, respectively. No patients died with evidence of cardiac disease. Three patients (2% with preexisting cardiac condition developed cardiac disease after treatment. Furthermore, the cardiac exposure was found to increase linearly with the irradiated heart volume while decreasing exponentially with the beam-to-heart distance.Compared to old technologies for lung cancer treatment, modern radiotherapy treatment modalities demonstrated better heart sparing. But the heart dose in lung cancer radiotherapy is still higher than that in the radiotherapy of breast cancer and Hodgkin's disease where cardiac complications have been extensively studied. With strong correlations of mean heart dose with beam-to-heart distance and irradiated heart volume, cautions should be exercised to avoid long-term cardiac toxicity in the lung cancer patients undergoing radiotherapy.

  6. Intensity-modulated radiotherapy for cancers in childhood; Radiotherapie conformationnelle par modulation d'intensite des tumeurs pediatriques

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    Leseur, J.; Le Prise, E. [Centre Eugene-Marquis, Service de Radiotherapie, 35 - Rennes (France); Leseur, J.; Carrie, C.; Beneyton, V. [Centre Leon-Berard, Service de Radiotherapie, 69 - Lyon (France); Bernier, V. [Centre Alexis-Vautrin, Service de Radiotherapie, 54 - Vandoeuvre-les-Nancy (France); Beneyton, V. [Centre Paul-Strauss, Service de Radiotherapie, 67 - Strasbourg (France); Mahee, M.A.; Supiot, S. [Centre Rene-Gauducheau, Service de Radiotherapie, 44 - Nantes - Saint-Herblain (France)

    2009-10-15

    Approximately 40-50% of children with cancer will be irradiated during their treatment. Intensity-modulated radiotherapy (I.M.R.T.) by linear accelerator or helical tomo-therapy improves dose distribution in target volumes and normal tissue sparing. This technology could be particularly useful for pediatric patients to achieve an optimal dose distribution in complex volumes close to critical structures. The use of I.M.R.T. can increase the volume of tissue receiving low-dose radiation, and consequently carcinogenicity in childhood population with a good overall survival and long period of life expectancy. This review will present the current and potential I.M.R.T. indications for cancers in childhood, and discuss the benefits and problems of this technology aiming to define recommendations in the use of I.M.R.T. and specific doses constraints in Pediatrics. (authors)

  7. The inaugural Frank Ellis Lecture--latrogenic cancer: the impact of intensity-modulated radiotherapy.

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    Hall, E J

    2006-05-01

    It is an honour and personal pleasure to give the inaugural Frank Ellis Lecture to celebrate his 100th birthday, and to acknowledge his enormous contributions to radiation oncology. Intensity-modulated radiotherapy (IMRT) allows dose to be concentrated in the tumour volume while sparing normal tissues. However, the downside to IMRT is the potential to increase the number of radiation-induced second cancers because more fields are used which involves a bigger volume of normal tissue exposed to lower doses. It has been estimated that IMRT may double the incidence of solid cancers in long-term survivors. This may be acceptable in older patients if balanced by an improvement in local tumour control and reduced toxicity. On the other hand, the incidence of second cancers is higher in children, so that doubling it may not be acceptable. IMRT represents a special case for children. First, they are more sensitive to radiation-induced cancer than adults. Second, radiation scattered from the treatment volume is more important in the small body of the child. Third, there is the question of genetic susceptibility, as many childhood cancers involve a germline mutation. The levels of leakage radiation in current Linacs can be reduced, but the cost would be substantial. An alternative strategy is to replace X-rays with protons. This is an advantage only if the proton machine uses a pencil scanning beam, as passive modulation of a scattering foil produces neutrons, which results in an effective dose to the patient higher than that characteristic of IMRT.

  8. Expert Consensus Contouring Guidelines for Intensity Modulated Radiation Therapy in Esophageal and Gastroesophageal Junction Cancer

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    Wu, Abraham J., E-mail: wua@mskcc.org [Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Bosch, Walter R. [Washington University, St. Louis, Missouri (United States); Chang, Daniel T. [Stanford Cancer Institute, Stanford, California (United States); Hong, Theodore S. [Massachusetts General Hospital, Boston, Massachusetts (United States); Jabbour, Salma K. [Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey (United States); Kleinberg, Lawrence R. [Johns Hopkins Medical Center, Baltimore, Maryland (United States); Mamon, Harvey J. [Brigham and Women' s Hospital, Boston, Massachusetts (United States); Thomas, Charles R. [Knight Cancer Institute, Oregon Health & Sciences University, Portland, Oregon (United States); Goodman, Karyn A. [Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2015-07-15

    Purpose/Objective(s): Current guidelines for esophageal cancer contouring are derived from traditional 2-dimensional fields based on bony landmarks, and they do not provide sufficient anatomic detail to ensure consistent contouring for more conformal radiation therapy techniques such as intensity modulated radiation therapy (IMRT). Therefore, we convened an expert panel with the specific aim to derive contouring guidelines and generate an atlas for the clinical target volume (CTV) in esophageal or gastroesophageal junction (GEJ) cancer. Methods and Materials: Eight expert academically based gastrointestinal radiation oncologists participated. Three sample cases were chosen: a GEJ cancer, a distal esophageal cancer, and a mid-upper esophageal cancer. Uniform computed tomographic (CT) simulation datasets and accompanying diagnostic positron emission tomographic/CT images were distributed to each expert, and the expert was instructed to generate gross tumor volume (GTV) and CTV contours for each case. All contours were aggregated and subjected to quantitative analysis to assess the degree of concordance between experts and to generate draft consensus contours. The panel then refined these contours to generate the contouring atlas. Results: The κ statistics indicated substantial agreement between panelists for each of the 3 test cases. A consensus CTV atlas was generated for the 3 test cases, each representing common anatomic presentations of esophageal cancer. The panel agreed on guidelines and principles to facilitate the generalizability of the atlas to individual cases. Conclusions: This expert panel successfully reached agreement on contouring guidelines for esophageal and GEJ IMRT and generated a reference CTV atlas. This atlas will serve as a reference for IMRT contours for clinical practice and prospective trial design. Subsequent patterns of failure analyses of clinical datasets using these guidelines may require modification in the future.

  9. Implementation of intensity modulated radiotherapy for prostate cancer in a private radiotherapy service in Mexico

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    Poitevin-Chacón, María Adela; Reséndiz González, Gabriel; Alvarado Zermeño, Adriana; Flores Castro, Jesús Manuel; Flores Balcázar, Christian Haydée; Rosales Pérez, Samuel; Pérez Pastenes, Miguel Angel; Rodríguez Laguna, Alejandro; Vázquez Fernández, Patricio; Calvo Fernández, Alejandro; Bastida Ventura, Jorge

    2014-01-01

    Intensity modulated radiation therapy (IMRT) allows physicians to deliver higher conformal doses to the tumour, while avoiding adjacent structures. As a result the probability of tumour control is higher and toxicity may be reduced. However, implementation of IMRT is highly complex and requires a rigorous quality assurance (QA) program both before and during treatment. The present article describes the process of implementing IMRT for localized prostate cancer in a radiation therapy department. In our experience, IMRT implementation requires careful planning due to the need to simultaneously implement specialized software, multifaceted QA programs, and training of the multidisciplinary team. Establishing standardized protocols and ensuring close collaboration between a multidisciplinary team is challenging but essential. PMID:25535587

  10. Patterns of Disease Recurrence Following Treatment of Oropharyngeal Cancer With Intensity Modulated Radiation Therapy

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    Garden, Adam S., E-mail: agarden@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Dong, Lei [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Morrison, William H. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Stugis, Erich M. [Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Glisson, Bonnie S. [Department of Thoracic/Head and Neck Medicine, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Frank, Steven J.; Beadle, Beth M.; Gunn, Gary B. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Schwartz, David L. [Department of Radiation Medicine, Long Island Jewish Medical Center, New Hyde Park, NY (United States); Kies, Merill S. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Department of Thoracic/Head and Neck Medicine, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Weber, Randal S. [Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Ang, K. Kian; Rosenthal, David I. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States)

    2013-03-15

    Purpose: To report mature results of a large cohort of patients diagnosed with squamous cell carcinoma of the oropharynx who were treated with intensity modulated radiation therapy (IMRT). Methods and Materials: The database of patients irradiated at The University of Texas, M.D. Anderson Cancer Center was searched for patients diagnosed with oropharyngeal cancer and treated with IMRT between 2000 and 2007. A retrospective review of outcome data was performed. Results: The cohort consisted of 776 patients. One hundred fifty-nine patients (21%) were current smokers, 279 (36%) former smokers, and 337 (43%) never smokers. T and N categories and American Joint Committee on Cancer group stages were distributed as follows: T1/x, 288 (37%); T2, 288 (37%); T3, 113 (15%); T4, 87 (11%); N0, 88(12%); N1/x, 140 (18%); N2a, 101 (13%); N2b, 269 (35%); N2c, 122 (16%); and N3, 56 (7%); stage I, 18(2%); stage II, 40(5%); stage III, 150(19%); and stage IV, 568(74%). Seventy-one patients (10%) presented with nodes in level IV. Median follow-up was 54 months. The 5-year overall survival, locoregional control, and overall recurrence-free survival rates were 84%, 90%, and 82%, respectively. Primary site recurrence developed in 7% of patients, and neck recurrence with primary site control in 3%. We could only identify 12 patients (2%) who had locoregional recurrence outside the high-dose target volumes. Poorer survival rates were observed in current smokers, patients with larger primary (T) tumors and lower neck disease. Conclusions: Patients with oropharyngeal cancer treated with IMRT have excellent disease control. Locoregional recurrence was uncommon, and most often occurred in the high dose volumes. Parotid sparing was accomplished in nearly all patients without compromising tumor coverage.

  11. Outcomes After Intensity-Modulated Versus Conformal Radiotherapy in Older Men With Nonmetastatic Prostate Cancer

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    Bekelman, Justin E., E-mail: bekelman@uphs.upenn.edu [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA (United States); Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, PA (United States); Mitra, Nandita [Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA (United States); Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA (United States); Efstathiou, Jason [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Liao Kaijun [Division of General Internal Medicine, University of Pennsylvania, Philadelphia, PA (United States); Sunderland, Robert; Yeboa, Deborah N. [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Armstrong, Katrina [Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA (United States); Division of General Internal Medicine, University of Pennsylvania, Philadelphia, PA (United States); Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA (United States); Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, PA (United States)

    2011-11-15

    Purpose: There is little evidence comparing complications after intensity-modulated (IMRT) vs. three-dimensional conformal radiotherapy (CRT) for prostate cancer. The study objective was to test the hypothesis that IMRT, compared with CRT, is associated with a reduction in bowel, urinary, and erectile complications in elderly men with nonmetastatic prostate cancer. Methods and Materials: We undertook an observational cohort study using registry and administrative claims data from the SEER-Medicare database. We identified men aged 65 years or older diagnosed with nonmetastatic prostate cancer in the United States between 2002 and 2004 who received IMRT (n = 5,845) or CRT (n = 6,753). The primary outcome was a composite measure of bowel complications. Secondary outcomes were composite measures of urinary and erectile complications. We also examined specific subsets of bowel (proctitis/hemorrhage) and urinary (cystitis/hematuria) events within the composite complication measures. Results: IMRT was associated with reductions in composite bowel complications (24-month cumulative incidence 18.8% vs. 22.5%; hazard ratio [HR] 0.86; 95% confidence interval [CI], 0.79-0.93) and proctitis/hemorrhage (HR 0.78; 95% CI, 0.64-0.95). IMRT was not associated with rates of composite urinary complications (HR 0.93; 95% CI, 0.83-1.04) or cystitis/hematuria (HR 0.94; 95% CI, 0.83-1.07). The incidence of erectile complications involving invasive procedures was low and did not differ significantly between groups, although IMRT was associated with an increase in new diagnoses of impotence (HR 1.27, 95% CI, 1.14-1.42). Conclusion: IMRT is associated with a small reduction in composite bowel complications and proctitis/hemorrhage compared with CRT in elderly men with nonmetastatic prostate cancer.

  12. Reduced Acute Bowel Toxicity in Patients Treated With Intensity-Modulated Radiotherapy for Rectal Cancer

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    Samuelian, Jason M. [Department of Radiation Oncology, Mayo Clinic, Scottsdale, AZ (United States); Callister, Matthew D., E-mail: Callister.matthew@mayo.edu [Department of Radiation Oncology, Mayo Clinic, Scottsdale, AZ (United States); Ashman, Jonathan B. [Department of Radiation Oncology, Mayo Clinic, Scottsdale, AZ (United States); Young-Fadok, Tonia M. [Division of Colorectal Surgery, Mayo Clinic, Scottsdale, AZ (United States); Borad, Mitesh J. [Division of Hematology-Oncology, Mayo Clinic, Scottsdale, AZ (United States); Gunderson, Leonard L. [Department of Radiation Oncology, Mayo Clinic, Scottsdale, AZ (United States)

    2012-04-01

    Purpose: We have previously shown that intensity-modulated radiotherapy (IMRT) can reduce dose to small bowel, bladder, and bone marrow compared with three-field conventional radiotherapy (CRT) technique in the treatment of rectal cancer. The purpose of this study was to review our experience using IMRT to treat rectal cancer and report patient clinical outcomes. Methods and Materials: A retrospective review was conducted of patients with rectal cancer who were treated at Mayo Clinic Arizona with pelvic radiotherapy (RT). Data regarding patient and tumor characteristics, treatment, acute toxicity according to the Common Terminology Criteria for Adverse Events v 3.0, tumor response, and perioperative morbidity were collected. Results: From 2004 to August 2009, 92 consecutive patients were treated. Sixty-one (66%) patients were treated with CRT, and 31 (34%) patients were treated with IMRT. All but 2 patients received concurrent chemotherapy. There was no significant difference in median dose (50.4 Gy, CRT; 50 Gy, IMRT), preoperative vs. postoperative treatment, type of concurrent chemotherapy, or history of previous pelvic RT between the CRT and IMRT patient groups. Patients who received IMRT had significantly less gastrointestinal (GI) toxicity. Sixty-two percent of patients undergoing CRT experienced {>=}Grade 2 acute GI side effects, compared with 32% among IMRT patients (p = 0.006). The reduction in overall GI toxicity was attributable to fewer symptoms from the lower GI tract. Among CRT patients, {>=}Grade 2 diarrhea and enteritis was experienced among 48% and 30% of patients, respectively, compared with 23% (p = 0.02) and 10% (p = 0.015) among IMRT patients. There was no significant difference in hematologic or genitourinary acute toxicity between groups. In addition, pathologic complete response rates and postoperative morbidity between treatment groups did not differ significantly. Conclusions: In the management of rectal cancer, IMRT is associated with a

  13. Adoption of Intensity Modulated Radiation Therapy For Early-Stage Breast Cancer From 2004 Through 2011

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    Wang, Elyn H. [Yale School of Medicine, New Haven, Connecticut (United States); Mougalian, Sarah S. [Yale School of Medicine, New Haven, Connecticut (United States); Yale Cancer Center, New Haven, Connecticut (United States); Cancer Outcomes, Public Policy, and Effectiveness Research Center at Yale, New Haven, Connecticut (United States); Soulos, Pamela R. [Yale School of Medicine, New Haven, Connecticut (United States); Cancer Outcomes, Public Policy, and Effectiveness Research Center at Yale, New Haven, Connecticut (United States); Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut (United States); Smith, Benjamin D. [Department of Radiation Oncology, MD Anderson Cancer Center, Houston, Texas (United States); Haffty, Bruce G. [Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey (United States); Gross, Cary P. [Yale School of Medicine, New Haven, Connecticut (United States); Cancer Outcomes, Public Policy, and Effectiveness Research Center at Yale, New Haven, Connecticut (United States); Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut (United States); Yu, James B., E-mail: james.b.yu@yale.edu [Yale School of Medicine, New Haven, Connecticut (United States); Cancer Outcomes, Public Policy, and Effectiveness Research Center at Yale, New Haven, Connecticut (United States); Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut (United States)

    2015-02-01

    Purpose: Intensity modulated radiation therapy (IMRT) is a newer method of radiation therapy (RT) that has been increasingly adopted as an adjuvant treatment after breast-conserving surgery (BCS). IMRT may result in improved cosmesis compared to standard RT, although at greater expense. To investigate the adoption of IMRT, we examined trends and factors associated with IMRT in women under the age of 65 with early stage breast cancer. Methods and Materials: We performed a retrospective study of early stage breast cancer patients treated with BCS followed by whole-breast irradiation (WBI) who were ≤65 years old in the National Cancer Data Base from 2004 to 2011. We used logistic regression to identify factors associated with receipt of IMRT (vs standard RT). Results: We identified 11,089 women with early breast cancer (9.6%) who were treated with IMRT and 104,448 (90.4%) who were treated with standard RT, after BCS. The proportion of WBI patients receiving IMRT increased yearly from 2004 to 2009, with 5.3% of WBI patients receiving IMRT in 2004 and 11.6% receiving IMRT in 2009. Further use of IMRT declined afterward, with the proportion remaining steady at 11.0% and 10.7% in 2010 and 2011, respectively. Patients treated in nonacademic community centers were more likely to receive IMRT (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.30-1.43 for nonacademic vs academic center). Compared to privately insured patients, the uninsured patients (OR, 0.81; 95% CI, 0.70-0.95) and those with Medicaid insurance (OR, 0.87; 95% CI, 0.79-0.95) were less likely to receive IMRT. Conclusions: The use of IMRT rose from 2004 to 2009 and then stabilized. Important nonclinical factors associated with IMRT use included facility type and insurance status.

  14. Adjuvant radiotherapy for gallbladder cancer: A dosimetric comparison of conformal radiotherapy and intensity-modulated radiotherapy

    Institute of Scientific and Technical Information of China (English)

    Xiao-Nan Sun; Qi Wang; Ben-Xing Gu; Yan-Hong Zhu; Jian-Bin Hu; Guo-Zhi Shi; Shu Zheng

    2011-01-01

    AIM: To assess the efficacy and toxicity of conformal radiotherapy (CRT) and compare with intensity-modulated radiotherapy (IMRT) in the treatment of gallbladder cancer.METHODS: Between November 2003 and January 2010, 20 patients with gallbladder cancer were treated with CRT with or without chemotherapy after surgical resection. Preliminary survival data were collected and examined using both Kaplan-Meier and actuarial analysis. Demographic and treatment parameters were collected. All patients were planned to receive 46-56 Gy in 1.8 or 2.0 Gy per fraction. CRT planning was compared with IMRT.RESULTS: The most common reported acute toxicities requiring medication (Radiation Therapy Oncology Group, Radiation Therapy Oncology Group Grade2) were nausea (10/20 patients) and diarrhea (3/20).There were no treatment-related deaths. Compared with CRT planning, IMRT significantly reduced the volume of right kidney receiving > 20 Gy and the volume of liver receiving > 30 Gy. IMRT has a negligible impact on the volume of left kidney receiving > 20 Gy. The 95% of prescribed dose for a planning tumor volume using either 3D CRT or IMRT planning were 84.0% ±6.7%, 82.9% ± 6.1%, respectively (P > 0.05).CONCLUSION: IMRT achieves similar excellent target coverage as compared with CRT planning, while reducingthe mean liver dose and volume above threshold dose. IMRT offers better sparing of the right kidney compared with CRT planning, with a significantly lower mean dose and volume above threshold dose.

  15. Comparative outcomes for three-dimensional conformal versus intensity-modulated radiation therapy for esophageal cancer.

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    Freilich, J; Hoffe, S E; Almhanna, K; Dinwoodie, W; Yue, B; Fulp, W; Meredith, K L; Shridhar, R

    2015-01-01

    Emerging data suggests a benefit for using intensity modulated radiation therapy (IMRT) for the management of esophageal cancer. We retrospectively reviewed patients treated at our institution who received definitive or preoperative chemoradiation with either IMRT or 3D conformal radiation therapy (3DCRT) between October 2000 and January 2012. Kaplan Meier analysis and the Cox proportional hazard model were used to evaluate survival outcomes. We evaluated a total of 232 patients (138 IMRT, 94 3DCRT) who received a median dose of 50.4 Gy (range, 44-64.8) to gross disease. Median follow up for all patients, IMRT patients alone, and 3DCRT patients alone was 18.5 (range, 2.5-124.2), 16.5 (range, 3-59), and 25.9 months (range, 2.5-124.2), respectively. We observed no significant difference based on radiation technique (3DCRT vs. IMRT) with respect to median overall survival (OS) (median 29 vs. 32 months; P = 0.74) or median relapse free survival (median 20 vs. 25 months; P = 0.66). On multivariable analysis (MVA), surgical resection resulted in improved OS (HR 0.444; P 20% weight loss (OR 0.51; P = 0.050). Our data suggest that while IMRT-based chemoradiation for esophageal cancer does not impact survival there was significantly less toxicity. In the IMRT group there was significant decrease in weight loss and grade ≥3 toxicity compared to 3DCRT.

  16. Comparison study of intensity modulated arc therapy using single or multiple arcs to intensity modulated radiation therapy for high-risk prostate cancer

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    Ashamalla, Hani; Tejwani, Ajay; Parameritis, Loannis; Swamy, Uma; Luo, Pei Ching; Guirguis, Adel; Lavaf, Amir [Weill Medical College of Cornell University, Brooklyn, NY (United States)

    2013-06-15

    Intensity modulated arc therapy (IMAT) is a form of intensity modulated radiation therapy (IMRT) that delivers dose in single or multiple arcs. We compared IMRT plans versus single-arc field (1ARC) and multi-arc fields (3ARC) IMAT plans in high-risk prostate cancer. Sixteen patients were studied. Prostate (PTV{sub P}), right pelvic (PTV{sub RtLN}) and left pelvic lymph nodes (PTV{sub LtLN}), and organs at risk were contoured. PTVP, PTV{sub RtLN}, and PTV{sub LtLN} received 50.40 Gy followed by a boost to PTV{sub B} of 28.80 Gy. Three plans were per patient generated: IMRT, 1ARC, and 3ARC. We recorded the dose to the PTV, the mean dose (D{sub MEAN}) to the organs at risk, and volume covered by the 50% isodose. Efficiency was evaluated by monitor units (MU) and beam on time (BOT). Conformity index (CI), Paddick gradient index, and homogeneity index (HI) were also calculated. Average Radiation Therapy Oncology Group CI was 1.17, 1.20, and 1.15 for IMRT, 1ARC, and 3ARC, respectively. The plans' HI were within 1% of each other. The D{sub MEAN} of bladder was within 2% of each other. The rectum D{sub MEAN} in IMRT plans was 10% lower dose than the arc plans (p < 0.0001). The GI of the 3ARC was superior to IMRT by 27.4% (p = 0.006). The average MU was highest in the IMRT plans (1686) versus 1ARC (575) versus 3ARC (1079). The average BOT was 6 minutes for IMRT compared to 1.3 and 2.9 for 1ARC and 3ARC IMAT (p < 0.05). For high-risk prostate cancer, IMAT may offer a favorable dose gradient profile, conformity, MU and BOT compared to IMRT.

  17. A treatment planning study of the potential of geometrical tracking for intensity modulated proton therapy of lung cancer

    DEFF Research Database (Denmark)

    af Rosenschöld, Per Munck; Aznar, Marianne C; Nygaard, Ditte E;

    2010-01-01

    Proton therapy of lung cancer holds the potential for a reduction of the volume of irradiated normal lung tissue. In this work we investigate the robustness of intensity modulated proton therapy (IMPT) plans to motion, and evaluate a geometrical tumour tracking method to compensate for tumour...

  18. Toxicity after intensity-modulated, image-guided radiotherapy for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Flentje, Michael [Dept. of Radiotherapy, Univ. Hospital Wuerzburg (Germany); Guckenberger, Matthias; Ok, Sami; Polat, Buelent; Sweeney, Reinhart A.

    2010-10-15

    Purpose: To evaluate toxicity after dose-escalated radiotherapy for prostate cancer using intensity-modulated treatment planning (IMRT) and image-guided treatment (IGRT) delivery. Patients and Methods: 100 patients were treated with simultaneous integrated boost (SIB) IMRT for prostate cancer: doses of 76.23 Gy and 60 Gy in 33 fractions were prescribed to the prostate and the seminal vesicles, respectively, for intermediate- and high-risk patients (n = 74). The total dose was 73.91 Gy in 32 fractions for low-risk patients and after transurethral resection of the prostate (n = 26). The pelvic lymphatics were treated with 46 Gy in 25 fractions in patients with high risk of lymph node metastases using an SIB to the prostate (n = 25). IGRT was practiced with cone-beam computed tomography. Acute and late gastrointestinal (GI) and genitourinary (GU) toxicity was evaluated prospectively (CTCAE v3.0). Results: Treatment was completed as planned by all patients. Acute GI and GU toxicity grade {>=} 2 was observed in 12% and 42% of the patients, respectively, with 4% suffering from GU toxicity grade 3. 6 weeks after treatment, the incidence of acute toxicity grade {>=} 2 had decreased to 12%. With a median follow-up of 26 months, late GI and GU toxicity grade {>=} 2 was seen in 1.5% and 7.7% of the patients at 24 months. Four patients developed late toxicity grade 3 (GI n = 1; GU n = 3). Presence of acute GI and GU toxicity was significantly associated with late GI (p = 0.0007) and GU toxicity (p = 0.006). Conclusion: High-dose radiotherapy for prostate cancer using IMRT and IGRT resulted in low rates of acute toxicity and preliminary results of late toxicity are promising. (orig.)

  19. Intensity modulated radiation therapy and chemotherapy for locally advanced pancreatic cancer: Results of feasibility study

    Institute of Scientific and Technical Information of China (English)

    Yong-Rui Bai; Guo-Hua Wu; Wei-Jian Guo; Xu-Dong Wu; Yuan Yao; Yin Chen; Ren-Hua Zhou; Dong-Qin Lu

    2003-01-01

    AIM: To explore whether intensity modulated radiation therapy (IMRT) in combination with chemotherapy could increase radiation dose to gross tumor volume without severe acute radiation related toxicity by decreasing the dose to the surrounding normal tissue in patients with locally advanced pancreatic cancer.METHODS: Twenty-one patients with locally advanced pancreatic cancer were evaluated in this clinical trial,Patients would receive the dose of IMRT from 21Gy to 30Gy in 7 to 10 fractions within two weeks after conventional radiotherapy of 30Gy in 15 fractions over 3 weeks. The total escalation tumor dose would be 51, 54,57, 60Gy, respectively. 5-fluororacil (5-FU) or gemcitabine was given concurrently with radiotherapy during the treatment course.RESULTS: Sixteen patients who had completed the radiotherapy plan with doses of 51Gy (3 cases), 54Gy (3 cases), 57Gy (3 cases) and 60Gy (7 cases) were included for evaluation. The median levels of CA19-9 prior to and after radiotherapy were 716 U/ml and 255 U/ml respectively (P<0.001) in 13 patients who demonstrated high levels of CA19-9 before radiotherapy. Fourteen patients who suffered from pain could reduce at least 1/3-1/2 amount of analgesic intake and 5 among these patients got complete relief of pain. Ten patients improved in Kamofsky performance status (KPS). The median follow-up period was 8 months and one-year survival rate was 35 %. No patient suffered more than grade Ⅲ acute toxicities induced by radiotherapy.CONCLUSION: Sixty Gy in 25 fractions over 5 weeks with late course IMRT technique combined with concurrent 5-FU chemotherapy can provide a definitely palliative benefit with tolerable acute radiation related toxicity for patients with advanced pancreatic cancer.

  20. Interfractional variability in intensity-modulated radiotherapy of prostate cancer with or without thermoplastic pelvic immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.A.; Kim, C.Y.; Park, Y.J.; Yoon, W.S.; Lee, N.K.; Yang, D.S. [Korea University Guro Hospital, Korea University College of Medicine, Department of Radiation Oncology, Seoul (Korea, Republic of)

    2014-01-15

    To determine the variability of patient positioning errors associated with intensity-modulated radiotherapy (IMRT) for prostate cancer and to assess the impact of thermoplastic pelvic immobilization on these errors using kilovoltage (kV) cone-beam computed tomography (CBCT). From February 2012 to June 2012, the records of 314 IMRT sessions in 19 patients with prostate cancer, performed with or without immobilization at two different facilities in the Korea University Hospital were analyzed. The kV CBCT images were matched to simulation computed tomography (CT) images to determine the simulation-to-treatment variability. The shifts along the x (lateral)-, y (longitudinal)- and z (vertical)-axes were measured, as was the shift in the three dimensional (3D) vector. The measured systematic errors in the immobilized group during treatment were 0.46 ± 1.75 mm along the x-axis, - 0.35 ± 3.83 mm along the y-axis, 0.20 ± 2.75 mm along the z-axis and 4.05 ± 3.02 mm in the 3D vector. Those of nonimmobilized group were - 1.45 ± 7.50 mm along the x-axis, 1.89 ± 5.07 mm along the y-axis, 0.28 ± 3.81 mm along the z-axis and 8.90 ± 4.79 mm in the 3D vector. The group immobilized with pelvic thermoplastics showed reduced interfractional variability along the x- and y-axes and in the 3D vector compared to the nonimmobilized group (p < 0.05). IMRT with thermoplastic pelvic immobilization in patients with prostate cancer appears to be useful in stabilizing interfractional variability during the planned treatment course. (orig.)

  1. Carotid sparing intensity modulated radiotherapy on early glottic cancer: Preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hoon Sik; Jeong, Bae Kwon; Jeong, Ho Jin; Song, Jin Ho; Kim, Jin Pyeong; Park, Jung Je; Woo, Seung Hoon; Kang, Ki Mun [Gyeongsang National University Hospital, Gyeongsang National University School of Medicine, Jinju (Korea, Republic of)

    2016-03-15

    To compare the dose distribution between carotid sparing intensity modulated radiotherapy (IMRT) and opposed lateral field technique (LAFT), and to determine the effects of carotid sparing IMRT in early glottic cancer patients who have risk factors for atherosclerosis. Ten early glottic cancer patients were treated with carotid sparing IMRT. For each patient, the conventional LAFT plan was developed for comparison. IMRT and LAFT plans were compared in terms of planning target volume (PTV) coverage, conformity index, homogeneity index, and the doses to planning organ at risk volume (PRV) for carotid arteries, spinal cord and pharyngeal constrictor muscle. Recurrence was not observed in any patients during the follow-up period. V95% for PTV showed no significant difference between IMRT and LAFT plans, while V100% was significantly higher in the IMRT plan (95.5% vs. 94.6%, p = 0.005). The homogeneity index (11.6%) and conformity index (1.4) in the IMRT plan were significantly better than those in the LAFT plans (8.5% and 5.1, respectively) (p = 0.005). The median V5Gy (90.0%), V25Gy (13.5%), and V50Gy (0%) for carotid artery PRV in the IMRT plan were significantly lower than those in the LAFT plan (99.1%, 89.0%, and 77.3%, respectively) (p = 0.005). Our study suggests that carotid sparing IMRT can significantly decrease the dose to carotid arteries compared to LAFT, and it would be considered for early glottic cancer patient with high risk of atherosclerosis.

  2. Retrospective Estimation of the Quality of Intensity-Modulated Radiotherapy Plans for Lung Cancer

    CERN Document Server

    Koo, Jihye; Chung, Weon Kuu; Kim, Dong Wook

    2015-01-01

    This study estimated the planning quality of intensity-modulated radiotherapy in 42 lung cancer cases to provide preliminary data for the development of a planning quality assurance algorithm. Organs in or near the thoracic cavity (ipsilateral lung, contralateral lung, heart, liver, esophagus, spinal cord, and bronchus) were selected as organs at risk (OARs). Radiotherapy plans were compared using the conformity index (CI), coverage index (CVI), and homogeneity index (HI) of the planning target volume (PTV), OAR-PTV distance and OAR-PTV overlap volume, and the V10Gy, V20Gy, and equivalent uniform dose (EUD) of the OARs. The CI, CVI, and HI of the PTV were 0.54 - 0.89 , 0.90 - 1.00 , and 0.11 - 0.41, respectively. The mean EUDs (V10Gy, V20Gy) of the ipsilateral lung, contralateral lung, esophagus, cord, liver, heart, and bronchus were 8.07 Gy (28.06, 13.17), 2.59 Gy (6.53, 1.18), 7.02 Gy (26.17, 12.32), 3.56 Gy (13.56, 4.48), 0.72 Gy (2.15, 0.91), 5.14 Gy (19.68, 8.62), and 10.56 Gy (36.08, 19.79), respectivel...

  3. Intensity modulated radiotherapy with concurrent chemotherapy for larynx preservation of advanced resectable hypopharyngeal cancer

    Directory of Open Access Journals (Sweden)

    Chao Hsing-Lung

    2010-05-01

    Full Text Available Abstract Background To analyze the rate of larynx preservation in patients of locally advanced hypopharyngeal cancer treated with intensity modulated radiotherapy (IMRT plus concurrent chemotherapy, and compare the results with patients treated with primary surgery. Methods Between January 2003 and November 2007, 14 patients were treated with primary surgery and 33 patients were treated with concurrent chemoradiotherapy (CCRT using IMRT technique. Survival rate, larynx preservation rate were calculated with the Kaplan-Meier method. Multivariate analysis was conducted for significant prognostic factors with Cox-regression method. Results The median follow-up was 19.4 months for all patients, and 25.8 months for those alive. The 5-year overall survival rate was 33% and 44% for primary surgery and definitive CCRT, respectively (p = 0.788. The 5-year functional larynx-preservation survival after IMRT was 40%. Acute toxicities were common, but usually tolerable. The rates of treatment-related mucositis (≥ grade 2 and pharyngitis (≥ grade 3 were higher in the CCRT group. For multivariate analysis, treatment response and cricoid cartilage invasion strongly correlated with survival. Conclusions IMRT plus concurrent chemotherapy may preserve the larynx without compromising survival. Further studies on new effective therapeutic agents are essential.

  4. Intensity modulated whole pelvic radiotherapy in patients with cervix cancer: analysis of acute toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Young Min; Lee, Hyung Sik; Hur, Won Joo; Cha, Moon Seok; Kim, Hyun Ho [School of Medicine, Dong-A University, Busan (Korea, Republic of)

    2006-12-15

    To evaluate acute toxicities in cervix cancer patients receiving intensity modulated whole pelvic radiation therapy (IM-WPRT). Between August 2004 and April 2006, 17 patients who underwent IM-WPRT were analysed. An intravenous contrast agent was used for radiotherapy planning computed tomography (CT). The central clinical target volume (CTV) included the primary tumor, uterus, vagina, and parametrium. The nodal CTV was defined as the lymph nodes larger than 1 cm seen on CT and the contrased-enhanced pelvic vessels. The planning target volume (PTV) was the 1-cm expanded volume around the central CTV, except for a 5-mm expansion from the posterior vagina, and the nodal PTV was defined as the nodal CTV plus a 1.5 cm margin. IM-WPRT was prescribed to deliver a dose of 50 Gy to more than 95% of the PTV. Acute toxicity was assessed with common toxicity criteria up to 60 days after radiotherapy. Grade 1 nausea developed in 10 (58.9%) patients, and grade 1 and 2 diarrhea developed in 11 (64.7%) and 1 (5.9%) patients, respectively. No grade 3 or higher gastrointestinal toxicity was seen. Leukopenia, anemia, and thrombocytopenia occurred in 15 (88.2%). 7 (41.2%), and 2 (11.8%) patients, respectively, as hematologic toxicities. Grade 3 leukopenia developed in 2 patients who were treated with concurrent chemoradiotherapy. IM-WPRT can be a useful treatment for cervix cancer patients with decreased severe acute toxicities and a resultant improved compliance to whole pelvic irradiation.

  5. Hypofractionated intensity-modulated radiotherapy in patients with localized prostate cancer: a preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hye Jin; Kay, Chul Seung; Son, Seok Hyun; Kim, Myung Soo; Jo, In Young; Lee, So Jung; Lee, Dong Hwan; Suh, Hong Jin; Choi, Yong Sun [Incheon St. Mary' s Hospital, The Catholic University of Korea College of Medicine, Incheon (Korea, Republic of)

    2016-03-15

    The aim of this work was to assess the efficacy and tolerability of hypofractionated intensity-modulated radiotherapy (IMRT) in patients with localized prostate cancer. Thirty-nine patients who received radical hypofractionated IMRT were retrospectively reviewed. Based on a pelvic lymph node involvement risk of 15% as the cutoff value, we decided whether to deliver treatment prostate and seminal vesicle only radiotherapy (PORT) or whole pelvis radiotherapy (WPRT). Sixteen patients (41%) received PORT with prostate receiving 45 Gy in 4.5 Gy per fraction in 2 weeks and the other 23 patients (59%) received WPRT with the prostate receiving 72 Gy in 2.4 Gy per fraction in 6 weeks. The median equivalent dose in 2 Gy fractions to the prostate was 79.9 Gy based on the assumption that the α/β ratio is 1.5 Gy. The median follow-up time was 38 months (range, 4 to 101 months). The 3-year biochemical failure-free survival rate was 88.2%. The 3-year clinical failure-free and overall survival rates were 94.5% and 96.3%, respectively. The rates of grade 2 acute genitourinary (GU) and gastrointestinal (GI) toxicities were 20.5% and 12.8%, respectively. None of the patients experienced grade ≥3 acute GU and GI toxicities. The grade 2-3 late GU and GI toxicities were found in 8.1% and 5.4% of patients, respectively. No fatal late toxicity was observed. Favorable biochemical control with low rates of toxicity was observed after hypofractionated IMRT, suggesting that our radiotherapy schedule can be an effective treatment option in the treatment of localized prostate cancer.

  6. Whole pelvic intensity-modulated radiotherapy for high-risk prostate cancer: a preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Ji Hyeon; Kim, Yeon Joo; Kim, Young Seok [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); and others

    2013-12-15

    To assess the clinical efficacy and toxicity of whole pelvic intensity-modulated radiotherapy (WP-IMRT) for high-risk prostate cancer. Patients with high-risk prostate cancer treated between 2008 and 2013 were reviewed. The study included patients who had undergone WP-IMRT with image guidance using electronic portal imaging devices and/or cone-beam computed tomography. The endorectal balloon was used in 93% of patients. Patients received either 46 Gy to the whole pelvis plus a boost of up to 76 Gy to the prostate in 2 Gy daily fractions, or 44 Gy to the whole pelvis plus a boost of up to 72.6 Gy to the prostate in 2.2 Gy fractions. The study cohort included 70 patients, of whom 55 (78%) had a Gleason score of 8 to 10 and 50 (71%) had a prostate-specific antigen level > 20 ng/mL. The androgen deprivation therapy was combined in 62 patients. The biochemical failure-free survival rate was 86.7% at 2 years. Acute any grade gastrointestinal (GI) and genitourinary (GU) toxicity rates were 47% and 73%, respectively. The actuarial rate of late grade 2 or worse toxicity at 2 years was 12.9% for GI, and 5.7% for GU with no late grade 4 toxicity. WP-IMRT was well tolerated with no severe acute or late toxicities, resulting in at least similar biochemical control to that of the historic control group with a small field. The long-term efficacy and toxicity will be assessed in the future, and a prospective randomized trial is needed to verify these findings.

  7. 3D radiation therapy or intensity-modulated radiotherapy for recurrent and metastatic cervical cancer: the Shanghai Cancer Hospital experience.

    Directory of Open Access Journals (Sweden)

    Su-Ping Liu

    Full Text Available We evaluate the outcomes of irradiation by using three-dimensional radiation therapy (3D-RT or intensity-modulated radiotherapy (IMRT for recurrent and metastatic cervical cancer. Between 2007 and 2010, 50 patients with recurrent and metastatic cervical cancer were treated using 3D-RT or IMRT. The median time interval between the initial treatment and the start of irradiation was 12 (6-51 months. Salvage surgery was performed before irradiation in 5 patients, and 38 patients received concurrent chemotherapy. Sixteen patients underwent 3D-RT, and 34 patients received IMRT. Median follow-up for all the patients was 18.3 months. Three-year overall survival and locoregional control were 56.1% and 59.7%, respectively. Three-year progression-free survival and disease-free survival were 65.3% and 64.3%, respectively. Nine patients developed grade 3 leukopenia. Grade 5 acute toxicity was not observed in any of the patients; however, 2 patients developed Grade 3 late toxicity. 3D-RT or IMRT is effective for the treatment of recurrent and metastatic cervical cancer, with the 3-year overall survival of 56.1%, and its complications are acceptable. Long-term follow-up and further studies are needed to confirm the role of 3D-RT or IMRT in the multimodality management of the disease.

  8. Intensity-modulated radiation therapy for oropharyngeal cancer: radiation dosage constraint at the anterior mandible.

    NARCIS (Netherlands)

    Verdonck, H.W.; Jong, J.M. de; Granzier, M.E.; Nieman, F.H.; Baat, C. de; Stoelinga, P.J.W.

    2009-01-01

    Because the survival of endosseous implants in irradiated bone is lower than in non-irradiated bone, particularly if the irradiation dose exceeds 50Gy, a study was carried out to assess the irradiation dose in the anterior mandible, when intensity modulated radiation therapy (IMRT) is used. The hypo

  9. Image guided position verification for intensity modulated radiotherapy of prostate cancer

    NARCIS (Netherlands)

    Nederveen, A.J.

    2002-01-01

    The aim of this thesis is to provide a practical framework for dose escalation in the prostate using intensity modulated radiotherapy (IMRT) and to find out if marker based on-line position verification is clinically feasible and effective. We present a class solution for dose escalation in the pros

  10. Dosimetric comparison using different multileaf collimeters in intensity-modulated radiotherapy for upper thoracic esophageal cancer

    Directory of Open Access Journals (Sweden)

    Fu Yuchuan

    2010-07-01

    Full Text Available Abstract Purpose To study the impacts of multileaf collimators (MLC width [standard MLC width of 10 mm (sMLC and micro-MLC width of 4 mm (mMLC] in the intensity-modulated radiotherapy (IMRT planning for the upper thoracic esophageal cancer (UTEC. Methods and materials 10 patients with UTEC were retrospectively planned with the sMLC and the mMLC. The monitor unites (MUs and dose volume histogram-based parameters [conformity index (CI and homogeneous index (HI] were compared between the IMRT plans with sMLC and with mMLC. Results The IMRT plans with the mMLC were more efficient (average MUs: 703.1 ± 68.3 than plans with the sMLC (average MUs: 833.4 ± 73.8 (p p 5 (3260.3 ± 374.0 vs 3404.5 ± 374.4/gEUD (1815.1 ± 281.7 vs 1849.2 ± 297.6 of the spinal cord, the V10 (33.2 ± 6.5 vs 34.0 ± 6.7, V20 (16.0 ± 4.6 vs 16.6 ± 4.7, MLD (866.2 ± 174.1 vs 887.9 ± 172.1 and gEUD (938.6 ± 175.2 vs 956.8 ± 171.0 of the lungs were observed in the plans with the mMLC, respectively (p Conclusions Comparing to the sMLC, the mMLC not only demonstrated higher efficiencies and more optimal target coverage, but also considerably improved the dose sparing of OARs in the IMRT planning for UTEC.

  11. Dosimetric Studies of Mixed Energy Intensity Modulated Radiation Therapy for Prostate Cancer Treatments

    Directory of Open Access Journals (Sweden)

    K. Abdul Haneefa

    2014-01-01

    Full Text Available Dosimetric studies of mixed field photon beam intensity modulated radiation therapy (IMRT for prostate cancer using pencil beam (PB and collapsed cone convolution (CCC algorithms using Oncentra MasterPlan treatment planning system (v. 4.3 are investigated in this study. Three different plans were generated using 6 MV, 15 MV, and mixed beam (both 6 and 15 MV. Fifteen patients with two sets of plans were generated: one by using PB and the other by using CCC for the same planning parameters and constraints except the beam energy. For each patient’s plan of high energy photons, one set of photoneutron measurements using solid state neutron track detector (SSNTD was taken for this study. Mean percentage of V66 Gy in the rectum is 18.55±2.8, 14.58±2.1, and 16.77±4.7 for 6 MV, 15 MV, and mixed-energy plans, respectively. Mean percentage of V66 Gy in bladder is 16.54±2.1, 17.42±2.1, and 16.94±41.9 for 6 MV, 15 MV, and mixed-energy plans, respectively. Mixed fields neutron contribution at the beam entrance surface is 45.62% less than at 15 MV photon beam. Our result shows that, with negligible neutron contributions, mixed field IMRT has considerable dosimetric advantage.

  12. Acute Esophagus Toxicity in Lung Cancer Patients After Intensity Modulated Radiation Therapy and Concurrent Chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kwint, Margriet [Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Uyterlinde, Wilma [Department of Thoracic Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Nijkamp, Jasper; Chen, Chun; Bois, Josien de; Sonke, Jan-Jakob [Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Heuvel, Michel van den [Department of Thoracic Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Knegjens, Joost; Herk, Marcel van [Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Belderbos, Jose, E-mail: j.belderbos@nki.nl [Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands)

    2012-10-01

    Purpose: The purpose of this study was to investigate the dose-effect relation between acute esophageal toxicity (AET) and the dose-volume parameters of the esophagus after intensity modulated radiation therapy (IMRT) and concurrent chemotherapy for patients with non-small cell lung cancer (NSCLC). Patients and Methods: One hundred thirty-nine patients with inoperable NSCLC treated with IMRT and concurrent chemotherapy were prospectively analyzed. The fractionation scheme was 66 Gy in 24 fractions. All patients received concurrently a daily dose of cisplatin (6 mg/m Superscript-Two ). Maximum AET was scored according to Common Toxicity Criteria 3.0. Dose-volume parameters V5 to V70, D{sub mean} and D{sub max} of the esophagus were calculated. A logistic regression analysis was performed to analyze the dose-effect relation between these parameters and grade {>=}2 and grade {>=}3 AET. The outcome was compared with the clinically used esophagus V35 prediction model for grade {>=}2 after radical 3-dimensional conformal radiation therapy (3DCRT) treatment. Results: In our patient group, 9% did not experience AET, and 31% experienced grade 1 AET, 38% grade 2 AET, and 22% grade 3 AET. The incidence of grade 2 and grade 3 AET was not different from that in patients treated with CCRT using 3DCRT. The V50 turned out to be the most significant dosimetric predictor for grade {>=}3 AET (P=.012). The derived V50 model was shown to predict grade {>=}2 AET significantly better than the clinical V35 model (P<.001). Conclusions: For NSCLC patients treated with IMRT and concurrent chemotherapy, the V50 was identified as most accurate predictor of grade {>=}3 AET. There was no difference in the incidence of grade {>=}2 AET between 3DCRT and IMRT in patients treated with concurrent chemoradiation therapy.

  13. Intensity Modulated Radiation Treatment of Prostate Cancer Guided by High Field MR Spectroscopic Imaging

    Science.gov (United States)

    2005-05-01

    Dempsey, F.A. Lerma , K.T. Bae, M.W. Vannier, and J.F. ogy 198, 795-805 (1996). Williamson, "Image-based dose planning of intracavitary brachytherapy:8L... River displacement and collimator and gantry angle misalignment (NJ): Prentice Hall; 1977. on intensity modulated radiation therapy. Radiother Oncol 41...Saddle River (NJ): Prentice Hall; 1993. radiation therapy planning. Phys Med Biol2001;46:2637-63. 76. Wu Q, Mohan R. Algorithms and functionality of

  14. Postoperative intensity modulated radiation therapy in high risk prostate cancer: a dosimetric comparison.

    Science.gov (United States)

    Digesú, Cinzia; Cilla, Savino; De Gaetano, Andrea; Massaccesi, Mariangela; Macchia, Gabriella; Ippolito, Edy; Deodato, Francesco; Panunzi, Simona; Iapalucci, Chiara; Mattiucci, Gian Carlo; D'Angelo, Elisa; Padula, Gilbert D A; Valentini, Vincenzo; Cellini, Numa; Piermattei, Angelo; Morganti, Alessio G

    2011-01-01

    The aim of this study was to compare intensity-modulated radiation therapy (IMRT) with 3D conformal technique (3D-CRT), with respect to target coverage and irradiation of organs at risk for high dose postoperative radiotherapy (PORT) of the prostate fossa. 3D-CRT and IMRT treatment plans were compared with respect to dose to the rectum and bladder. The dosimetric comparison was carried out in 15 patients considering 2 different scenarios: (1) exclusive prostate fossa irradiation, and (2) pelvic node irradiation followed by a boost on the prostate fossa. In scenario (1), a 3D-CRT plan (box technique) and an IMRT plan were calculated and compared for each patient. In scenario (2), 3 treatment plans were calculated and compared for each patient: (a) 3D-CRT box technique for both pelvic (prophylactic nodal irradiation) and prostate fossa irradiation (3D-CRT only); (b) 3D-CRT box technique for pelvic irradiation followed by an IMRT boost to the prostatic fossa (hybrid 3D-CRT and IMRT); and (c) IMRT for both pelvic and prostate fossa irradiation (IMRT only). For exclusive prostate fossa irradiation, IMRT significantly reduced the dose to the rectum (lower Dmean, V50%, V75%, V90%, V100%, EUD, and NTCP) and the bladder (lower Dmean, V50%, V90%, EUD and NTCP). When prophylactic irradiation of the pelvis was also considered, plan C (IMRT only) performed better than plan B (hybrid 3D-CRT and IMRT) as respect to both rectum and bladder irradiation (reduction of Dmean, V50%, V75%, V90%, equivalent uniform dose [EUD], and normal tissue complication probability [NTCP]). Plan (b) (hybrid 3D-CRT and IMRT) performed better than plan (a) (3D-CRT only) with respect to dose to the rectum (lower Dmean, V75%, V90%, V100%, EUD, and NTCP) and the bladder (Dmean, EUD, and NTCP). Postoperative IMRT in prostate cancer significantly reduces rectum and bladder irradiation compared with 3D-CRT.

  15. Optimal beam design on intensity-modulated radiation therapy with simultaneous integrated boost in nasopharyngeal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Mei-Chun [Division of Radiation Oncology, Department of Oncology Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China); Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan (China); Hu, Yu-Wen; Liu, Ching-Sheng [Department of Radiation Oncology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Lee, Jeun-Shenn [Division of Radiation Oncology, Department of Oncology Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China); Huang, Pin-I; Yen, Sang-Hue; Lee, Yuh-Lin; Hsieh, Chun-Mei [Department of Radiation Oncology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Shiau, Cheng-Ying, E-mail: cyshiau@vghtpe.gov.tw [Department of Radiation Oncology, Taichung Veterans General Hospital, Taichung, Taiwan (China)

    2014-10-01

    This study aims to determine the optimal beam design among various combinations of field numbers and beam trajectories for intensity-modulated radiation therapy (IMRT) with simultaneous integrated boost (SIB) technique for the treatment of nasopharyngeal cancer (NPC). We used 10 fields with gantry angles of 155°, 130°, 75°, 25°, 0° L, 0° R, 335°, 285°, 230°, and 205° denoted as F10. To decrease doses in the spinal cord, the F10 technique was designed by featuring 2 pairs of split-opposed beam fields at 155° to 335° and 205° to 25°, as well as one pair of manually split beam fields at 0°. The F10 technique was compared with 4 other common field arrangements: F7E, 7 fields with 50° equally spaced gantry angles; F7, the basis of F10 with 155°, 130°, 75°, 0°, 285°, 230°, and 205°; F9E, 9 fields with 40° equally spaced gantry angles; and FP, 7 posterior fields with 180°, 150°, 120°, 90°, 270°, 240°, and 210°. For each individual case of 10 patients, the customized constraints derived after optimization with the standard F10 technique were applied to 4 other field arrangements. The 4 new optimized plans of each individual case were normalized to achieve the same coverage of planning target volume (PTV){sub 63} {sub Gy} as that of the standard F10 technique. The F10 field arrangement exhibited the best coverage in PTV{sub 70} {sub Gy} and the least mean dose in the trachea-esophagus region. Furthermore, the F10 field arrangement demonstrated the highest level of conformity in the low-dose region and the least monitor unit. The F10 field arrangement performed more outstandingly than the other field arrangements in PTV{sub 70} {sub Gy} coverage and spared the central organ. This arrangement also exhibited the highest conformity and delivery efficiency. The F10 technique is recommended as the standard beam geometry for the SIB-IMRT of NPC.

  16. Postoperative Intensity-Modulated Arc Therapy for Cervical and Endometrial Cancer: A Prospective Report on Toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Vandecasteele, Katrien, E-mail: Katrien.Vandecasteele@uzgent.be [Department of Radiation Oncology, Ghent University Hospital, Ghent (Belgium); Tummers, Philippe; Makar, Amin [Department of Gynecologic Oncology, Ghent University Hospital, Ghent (Belgium); Eijkeren, Marc van [Department of Radiation Oncology, Ghent University Hospital, Ghent (Belgium); Delrue, Louke [Department of Radiology, Ghent University Hospital, Ghent (Belgium); Denys, Hannelore [Department of Medical Oncology, Ghent University Hospital, Ghent (Belgium); Lambert, Bieke [Department of Nuclear Medicine, Ghent University Hospital, Ghent (Belgium); Beerens, Anne-Sophie [Department of Pathology, Ghent University Hospital, Ghent (Belgium); Van den Broecke, Rudy [Department of Gynecologic Oncology, Ghent University Hospital, Ghent (Belgium); Lambein, Kathleen [Department of Pathology, Ghent University Hospital, Ghent (Belgium); Fonteyne, Valerie; De Meerleer, Gert [Department of Radiation Oncology, Ghent University Hospital, Ghent (Belgium)

    2012-10-01

    Purpose: To report on toxicity after postoperative intensity-modulated arc therapy (IMAT) for cervical (CC) and endometrial cancer (EC). Methods and Materials: Twenty-four CC and 41 EC patients were treated with postoperative IMAT. If indicated, para-aortic lymph node irradiation (preventive or when affected, PALN) and/or concomitant cisplatin (40 mg/m Superscript-Two , weekly) was administered. The prescribed dose for IMAT was 45 Gy (CC, 25 fractions) and 46 Gy (EC, 23 fractions), followed by a brachytherapeutic boost if possible. Radiation-related toxicity was assessed prospectively. The effect of concomitant cisplatin and PALN irradiation was evaluated. Results: Regarding acute toxicity (n = 65), Grade 3 and 2 acute gastrointestinal toxicity was observed in zero and 63% of patients (79% CC, 54% EC), respectively. Grade 3 and 2 acute genitourinary toxicity was observed in 1% and 18% of patients, respectively. Grade 2 (21%) and 3 (12%) hematologic toxicity (n = 41) occurred only in CC patients. Seventeen percent of CC patients and 2% of EC patients experienced Grade 2 fatigue and skin toxicity, respectively. Adding cisplatin led to an increase in Grade >2 nausea (57% vs. 9%; p = 0.01), Grade 2 nocturia (24% vs. 4%; p = 0.03), Grade {>=}2 hematologic toxicity (38% vs. nil, p = 0.003), Grade {>=}2 leukopenia (33% vs. nil, p = 0.009), and a strong trend toward more fatigue (14% vs. 2%; p = 0.05). Para-aortic lymph node irradiation led to an increase of Grade 2 nocturia (31% vs. 4%, p = 0.008) and a strong trend toward more Grade >2 nausea (44% vs. 18%; p = 0.052). Regarding late toxicity (n = 45), no Grade 3 or 4 late toxicity occurred. Grade 2 gastrointestinal toxicity, genitourinary toxicity, and fatigue occurred in 4%, 9%, and 1% of patients. Neither concomitant cisplatin nor PALN irradiation increased late toxicity rates. Conclusions: Postoperative IMAT for EC or CC is associated with low acute and late toxicity. Concomitant chemotherapy and PALN irradiation

  17. Simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) in nasopharyngeal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Studer, Gabriela [Dept. of Radiation Oncology, Univ. Hospital, Zurich (Switzerland); Peponi, Evangelia; Glanzmann, Christoph; Kunz, Guntram; Renner, Christoph; Tomuschat, Katja

    2010-03-15

    Purpose: To assess the efficacy and safety of using simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) to treat nasopharyngeal cancer (NPC) in a Caucasian cohort. Outcome was analyzed with respect to dose-volume histogram (DVH) values. Patients and Methods: Between 03/2002 and 01/2008, 39 NPC patients underwent SIB-IMRT (37 Caucasians; 31 males; mean age 53 years [16-78 years]). 41% presented with WHO (World Health Organization) type 1 unfavorable histology, 85% with stage III/IV disease. 19 patients had total gross tumor volume (GTV) 16-70 cm{sup 3} (mean 36 cm{sup 3}), while 16 had GTV > 70 cm{sup 3} (73-217 cm{sup 3}; mean 115 cm{sup 3}). All patients with stage II-IV disease received concomitant cisplatin. The prescribed SIB dose delivered to the planning target volume (PTV) was 70 Gy (2.00 Gy/fraction) in 17, 69.6 Gy (2.11 Gy/fraction) in 19, and 66 Gy (2.20 Gy/fraction) in three patients. Results: 3-year local relapse-free, nodal relapse-free, distant metastases-free, disease-free rates and overall survival were 86%, 89%, 85%, 72%, and 85% (median follow-up 30 months [8-71 months]). Histology was a significant prognostic factor concerning overall survival, with worst prognosis in WHO type 1 compared to type 2/3 (75% vs. 93%; p = 0.03). There was a trend in favor of WHO type 2/3 regarding local control (74% vs. 94%; p = 0.052). The PTV DVHs showed a slight left shift compared to reported series. Three patients developed grade 3 late effects (xerostomia [n=2], dysphagia [n=1], hearing loss [n=1]). Conclusion: In comparison with predominantly Asian NPC IMRT series in the literature, chemo-IMRT in the own Caucasian cohort, characterized by less radioresponsive WHO type 1, was equally effective. Treatment tolerance was excellent. (orig.)

  18. Larynx-sparing techniques using intensity-modulated radiation therapy for oropharyngeal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Bar Ad, Voichita, E-mail: voichita.bar-ad@jeffersonhospital.org [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Lin, Haibo [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Hwang, Wei-Ting [Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA (United States); Deville, Curtiland [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Dutta, Pinaki R. [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA (United States); Tochner, Zelig; Both, Stefan [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States)

    2012-01-01

    The purpose of the current study was to explore whether the laryngeal dose can be reduced by using 2 intensity-modulated radiation therapy (IMRT) techniques: whole-neck field IMRT technique (WF-IMRT) vs. junctioned IMRT (J-IMRT). The effect on planning target volumes (PTVs) coverage and laryngeal sparing was evaluated. WF-IMRT technique consisted of a single IMRT plan, including the primary tumor and the superior and inferior neck to the level of the clavicular heads. The larynx was defined as an organ at risk extending superiorly to cover the arytenoid cartilages and inferiorly to include the cricoid cartilage. The J-IMRT technique consisted of an IMRT plan for the primary tumor and the superior neck, matched to conventional antero-posterior opposing lower neck fields at the level of the thyroid notch. A central block was used for the anterior lower neck field at the level of the larynx to restrict the dose to the larynx. Ten oropharyngeal cancer cases were analyzed. Both the primary site and bilateral regional lymphatics were included in the radiotherapy targets. The averaged V95 for the PTV57.6 was 99.2% for the WF-IMRT technique compared with 97.4% (p = 0.02) for J-IMRT. The averaged V95 for the PTV64 was 99.9% for the WF-IMRT technique compared with 98.9% (p = 0.02) for J-IMRT and the averaged V95 for the PT70 was 100.0% for WF-IMRT technique compared with 99.5% (p = 0.04) for J-IMRT. The averaged mean laryngeal dose was 18 Gy with both techniques. The averaged mean doses within the matchline volumes were 69.3 Gy for WF-MRT and 66.2 Gy for J-IMRT (p = 0.03). The WF-IMRT technique appears to offer an optimal coverage of the target volumes and a mean dose to the larynx similar with J-IMRT and should be further evaluated in clinical trials.

  19. Larynx-sparing techniques using intensity-modulated radiation therapy for oropharyngeal cancer.

    Science.gov (United States)

    Bar Ad, Voichita; Lin, Haibo; Hwang, Wei-Ting; Deville, Curtiland; Dutta, Pinaki R; Tochner, Zelig; Both, Stefan

    2012-01-01

    The purpose of the current study was to explore whether the laryngeal dose can be reduced by using 2 intensity-modulated radiation therapy (IMRT) techniques: whole-neck field IMRT technique (WF-IMRT) vs. junctioned IMRT (J-IMRT). The effect on planning target volumes (PTVs) coverage and laryngeal sparing was evaluated. WF-IMRT technique consisted of a single IMRT plan, including the primary tumor and the superior and inferior neck to the level of the clavicular heads. The larynx was defined as an organ at risk extending superiorly to cover the arytenoid cartilages and inferiorly to include the cricoid cartilage. The J-IMRT technique consisted of an IMRT plan for the primary tumor and the superior neck, matched to conventional antero-posterior opposing lower neck fields at the level of the thyroid notch. A central block was used for the anterior lower neck field at the level of the larynx to restrict the dose to the larynx. Ten oropharyngeal cancer cases were analyzed. Both the primary site and bilateral regional lymphatics were included in the radiotherapy targets. The averaged V95 for the PTV57.6 was 99.2% for the WF-IMRT technique compared with 97.4% (p = 0.02) for J-IMRT. The averaged V95 for the PTV64 was 99.9% for the WF-IMRT technique compared with 98.9% (p = 0.02) for J-IMRT and the averaged V95 for the PT70 was 100.0% for WF-IMRT technique compared with 99.5% (p = 0.04) for J-IMRT. The averaged mean laryngeal dose was 18 Gy with both techniques. The averaged mean doses within the matchline volumes were 69.3 Gy for WF-MRT and 66.2 Gy for J-IMRT (p = 0.03). The WF-IMRT technique appears to offer an optimal coverage of the target volumes and a mean dose to the larynx similar with J-IMRT and should be further evaluated in clinical trials.

  20. A Phase 1 Study of Everolimus + Weekly Cisplatin + Intensity Modulated Radiation Therapy in Head-and-Neck Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Fury, Matthew G. [Department of Medicine, Head and Neck Oncology Service, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Medicine, Weill Cornell Medical College, New York, New York (United States); Lee, Nancy Y. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Sherman, Eric; Ho, Alan L. [Department of Medicine, Head and Neck Oncology Service, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Medicine, Weill Cornell Medical College, New York, New York (United States); Rao, Shyam [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Heguy, Adriana [Department of Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Shen, Ronglai [Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Korte, Susan; Lisa, Donna [Department of Medicine, Head and Neck Oncology Service, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Ganly, Ian; Patel, Snehal; Wong, Richard J.; Shaha, Ashok; Shah, Jatin [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Haque, Sofia [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Katabi, Nora [Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Pfister, David G. [Department of Medicine, Head and Neck Oncology Service, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Medicine, Weill Cornell Medical College, New York, New York (United States)

    2013-11-01

    Purpose: Elevated expression of eukaryotic protein synthesis initiation factor 4E (eIF4E) in histologically cancer-free margins of resected head and neck squamous cell carcinomas (HNSCCs) is mediated by mammalian target of rapamycin complex 1 (mTORC1) and has been associated with increased risk of disease recurrence. Preclinically, inhibition of mTORC1 with everolimus sensitizes cancer cells to cisplatin and radiation. Methods and Materials: This was single-institution phase 1 study to establish the maximum tolerated dose of daily everolimus given with fixed dose cisplatin (30 mg/m{sup 2} weekly × 6) and concurrent intensity modulated radiation therapy for patients with locally and/or regionally advanced head-and-neck cancer. The study had a standard 3 + 3 dose-escalation design. Results: Tumor primary sites were oral cavity (4), salivary gland (4), oropharynx (2), nasopharynx (1), scalp (1), and neck node with occult primary (1). In 4 of 4 cases in which resected HNSCC surgical pathology specimens were available for immunohistochemistry, elevated expression of eIF4E was observed in the cancer-free margins. The most common grade ≥3 treatment-related adverse event was lymphopenia (92%), and dose-limiting toxicities (DLTs) were mucositis (n=2) and failure to thrive (n=1). With a median follow up of 19.4 months, 2 patients have experienced recurrent disease. The maximum tolerated dose was everolimus 5 mg/day. Conclusions: Head-and-neck cancer patients tolerated everolimus at therapeutic doses (5 mg/day) given with weekly cisplatin and intensity modulated radiation therapy. The regimen merits further evaluation, especially among patients who are status post resection of HNSCCs that harbor mTORC1-mediated activation of eIF4E in histologically negative surgical margins.

  1. Dosimetric comparison of hybrid volumetric-modulated arc therapy, volumetric-modulated arc therapy, and intensity-modulated radiation therapy for left-sided early breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jia-Fu [Department of Radiation Physics, Taichung Veterans General Hospital, Taichung, Taiwan (China); Yeh, Dah-Cherng [Department of General Surgery, Taichung Veterans General Hospital, Taichung, Taiwan (China); Yeh, Hui-Ling, E-mail: hlyeh@vghtc.gov.tw [Department of Radiation Oncology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Chang, Chen-Fa [Department of Radiation Physics, Taichung Veterans General Hospital, Taichung, Taiwan (China); Lin, Jin-Ching [Department of Radiation Oncology, Taichung Veterans General Hospital, Taichung, Taiwan (China)

    2015-10-01

    To compare the dosimetric performance of 3 different treatment techniques: hybrid volumetric-modulated arc therapy (hybrid-VMAT), pure-VMAT, and fixed-field intensity-modulated radiation therapy (F-IMRT) for whole-breast irradiation of left-sided early breast cancer. The hybrid-VMAT treatment technique and 2 other treatment techniques—pure-VMAT and F-IMRT—were compared retrospectively in 10 patients with left-sided early breast cancer. The treatment plans of these patients were replanned using the same contours based on the original computed tomography (CT) data sets. Dosimetric parameters were calculated to evaluate plan quality. Total monitor units (MUs) and delivery time were also recorded and evaluated. The hybrid-VMAT plan generated the best results in dose coverage of the target and the dose uniformity inside the target (p < 0.0001 for conformal index [CI]; p = 0.0002 for homogeneity index [HI] of planning target volume [PTV]{sub 50.4} {sub Gy} and p < 0.0001 for HI of PTV{sub 62} {sub Gy}). Volumes of ipsilateral lung irradiated to doses of 20 Gy (V{sub 20} {sub Gy}) and 5 Gy (V{sub 5} {sub Gy}) by the hybrid-VMAT plan were significantly less than those of the F-IMRT and the pure-VMAT plans. The volume of ipsilateral lung irradiated to a dose of 5 Gy was significantly less using the hybrid-VMAT plan than that using the F-IMRT or the pure-VMAT plan. The total mean MUs for the hybrid-VMAT plan were significantly less than those for the F-IMRT or the pure-VMAT plan. The mean machine delivery time was 3.23 ± 0.29 minutes for the hybrid-VMAT plans, which is longer than that for the pure-VMAT plans but shorter than that for the F-IMRT plans. The hybrid-VMAT plan is feasible for whole-breast irradiation of left-sided early breast cancer.

  2. Effect of intensiti modulated radiation therapy according to equivalent uniform dose optimization method on patients with lung cancer

    Institute of Scientific and Technical Information of China (English)

    Yu-Fu Zhou; Qian Sun; Ya-Jun Zhang; Geng-Ming Wang; Bin He; Tao Qi; An Zhou

    2016-01-01

    Objective:To analyze the effect of the intensity modulated radiation therapy according to equivalent uniform dose optimization method on patients with lung cancer.Methods:A total of 82 cases of non-small cell lung cancer were divided into observation group and control group according to the random number table method. Patients in the control group received conventional radiotherapy while observation group received intensity modulated radiotherapy based on equivalent uniform dose optimization method. The treatment effects, survival times, blood vessel-related factors, blood coagulation function and the levels of inflammatory factors and so on were compared between the two groups of patients.Results:The effective rate of the observation group after treatment was higher than that of the control group. Progression free survival and median overall survival times were longer than those of patients in the control group (P<0.05). The serum VEGF and HIF-αα levels as well as D-D, TT, PT, APTT and FIB levels were lower in observation group patients after treatment than those in the control group(P<0.05). At the same time point, serum TNF-αα, CRP and PCT levels in the observation group after treatment were lower than those in the control group (P<0.05). Serum M2-PK, CA125, CEA and SCC values of patients in the observation group after treatment were all significantly lower than those in the control group (P< 0.05).Conclusions:Intensity modulated radiation therapy based on equivalent uniform dose optimized method can improve the treatment effect, prolong the survival time, optimize micro inflammatory environment and inhibit tumor biological behavior at the same time.

  3. The Dosimetric Consequences of Intensity Modulated Radiotherapy for Cervix Cancer: The Impact of Organ Motion, Deformation and Tumour Regression

    Science.gov (United States)

    Lim, Karen Siah Huey

    Hypothesis: In intensity modulated radiotherapy (IMRT) for cervix cancer, the dose received by the tumour target and surrounding normal tissues is significantly different to that indicated by a single static plan. Rationale: The optimal use of IMRT in cervix cancer requires a greater attention to clinical target volume (CTV) definition and tumour & normal organ motion to assure maximum tumour control with the fewest side effects. Research Aims: 1) Generate consensus CTV contouring guidelines for cervix cancer; 2) Evaluate intra-pelvic tumour and organ dynamics during radiotherapy; 3) Analyze the dose consequences of intra-pelvic organ dynamics on different radiotherapy strategies. Results: Consensus CTV definitions were generated using experts-in-the-field. Substantial changes in tumour volume and organ motion, resulted in significant reductions in accumulated dose to tumour targets and variability in accumulated dose to surrounding normal tissues. Significance: Formalized CTV definitions for cervix cancer is important in ensuring consistent standards of practice. Complex and unpredictable tumour and organ dynamics mandates daily soft-tissue image guidance if IMRT is used. To maximize the benefits of IMRT for cervix cancer, a strategy of adaptation is necessary.

  4. Comparative analysis of volumetric-modulated arc therapy and intensity-modulated radiotherapy for base of tongue cancer

    Directory of Open Access Journals (Sweden)

    L Nithya

    2014-01-01

    Full Text Available The aim of this study was to compare the various dosimetric parameters of dynamic multileaf collimator (MLC intensity modulated radiation therapy (IMRT plans with volumetric modulated arc therapy (VMAT plans for base of tongue cases. All plans were done in Monaco planning system for Elekta synergy linear accelerator with 80 MLC. IMRT plans were planned with nine stationary beams, and VMAT plans were done for 360° arc with single arc or dual arc. The dose to the planning target volumes (PTV for 70, 63, and 56 Gy was compared. The dose to 95, 98, and 50% volume of PTV were analyzed. The homogeneity index (HI and the conformity index (CI of the PTV 70 were also analyzed. IMRT and VMAT plan showed similar dose coverage, HI, and CI. Maximum dose and dose to 1-cc volume of spinal cord, planning risk volume (PRV cord, and brain stem were compared. IMRT plan and VMAT plan showed similar results except for the 1 cc of PRV cord that received slightly higher dose in VMAT plan. Mean dose and dose to 50% volume of right and left parotid glands were analyzed. VMAT plan gave better sparing of parotid glands than IMRT. In normal tissue dose analyses VMAT was better than IMRT. The number of monitor units (MU required for delivering the good quality of the plan and the time required to deliver the plan for IMRT and VMAT were compared. The number of MUs for VMAT was higher than that of IMRT plans. However, the delivery time was reduced by a factor of two for VMAT compared with IMRT. VMAT plans yielded good quality of the plan compared with IMRT, resulting in reduced treatment time and improved efficiency for base of tongue cases.

  5. A prospective comparison of acute intestinal toxicity following whole pelvic versus small field intensity-modulated radiotherapy for prostate cancer

    Directory of Open Access Journals (Sweden)

    Kim YJ

    2016-03-01

    Full Text Available Yeon Joo Kim, Jin-hong Park, In-Ha Yun, Young Seok KimDepartment of Radiation Oncology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Republic of KoreaPurpose: To compare the acute intestinal toxicity of whole pelvic (WP and small field (SF intensity-modulated radiotherapy (IMRT for prostate cancer using dosimetric and metabolic parameters as well as clinical findings.Methods: Patients who received IMRT in either a definitive or postoperative setting were prospectively enrolled. Target volume and organs at risk including intestinal cavity (IC were delineated in every patient by a single physician. The IC volume that received a 10–50 Gy dose at 5-Gy intervals (V10–V50 and the percentage of irradiated volume as a fraction of total IC volume were calculated. Plasma citrulline levels, as an objective biological marker, were checked at three time points: baseline and after exposure to 30 Gy and 60 Gy.Results: Of the 41 patients, only six experienced grade 1 acute intestinal toxicity. Although all dose–volume parameters were significantly worse following WP than SF IMRT, there was no statistically significant relationship between these dosimetric parameters and clinical symptoms. Plasma citrulline levels did not show a serial decrease by radiotherapy volume difference (WP versus SF and were not relevant to the irradiated doses.Conclusion: Given that WP had comparable acute intestinal toxicities to those associated with SF, WP IMRT appears to be a feasible approach for the treatment of prostate cancer despite dosimetric disadvantages.Keywords: prostate cancer, intensity-modulated radiotherapy, intestinal toxicity, citrulline

  6. Dosimetric and radiobiological comparison of Forward Tangent Intensity Modulated Radiation Therapy (FT-IMRT) and Volumetric Modulated Arc Therapy (VMAT) for early stage whole breast cancer

    Science.gov (United States)

    Moshiri Sedeh, Nader

    Intensity Modulated Radiation Therapy (IMRT) is a well-known type of external beam radiation therapy. The advancement in technology has had an inevitable influence in radiation oncology as well that has led to a newer and faster dose delivery technique called Volumetric Modulated Arc Therapy (VMAT). Since the presence of the VMAT modality in clinics in the late 2000, there have been many studies in order to compare the results of the VMAT modality with the current popular modality IMRT for various tumor sites in the body such as brain, prostate, head and neck, cervix and anal carcinoma. This is the first study to compare VMAT with IMRT for breast cancer. The results show that the RapidArc technique in Eclipse version 11 does not improve all aspects of the treatment plans for the breast cases automatically and easily, but it needs to be manipulated by extra techniques to create acceptable plans thus further research is needed.

  7. Automatically-generated rectal dose constraints in intensity-modulated radiation therapy for prostate cancer

    Science.gov (United States)

    Hwang, Taejin; Kim, Yong Nam; Kim, Soo Kon; Kang, Sei-Kwon; Cheong, Kwang-Ho; Park, Soah; Yoon, Jai-Woong; Han, Taejin; Kim, Haeyoung; Lee, Meyeon; Kim, Kyoung-Joo; Bae, Hoonsik; Suh, Tae-Suk

    2015-06-01

    The dose constraint during prostate intensity-modulated radiation therapy (IMRT) optimization should be patient-specific for better rectum sparing. The aims of this study are to suggest a novel method for automatically generating a patient-specific dose constraint by using an experience-based dose volume histogram (DVH) of the rectum and to evaluate the potential of such a dose constraint qualitatively. The normal tissue complication probabilities (NTCPs) of the rectum with respect to V %ratio in our study were divided into three groups, where V %ratio was defined as the percent ratio of the rectal volume overlapping the planning target volume (PTV) to the rectal volume: (1) the rectal NTCPs in the previous study (clinical data), (2) those statistically generated by using the standard normal distribution (calculated data), and (3) those generated by combining the calculated data and the clinical data (mixed data). In the calculated data, a random number whose mean value was on the fitted curve described in the clinical data and whose standard deviation was 1% was generated by using the `randn' function in the MATLAB program and was used. For each group, we validated whether the probability density function (PDF) of the rectal NTCP could be automatically generated with the density estimation method by using a Gaussian kernel. The results revealed that the rectal NTCP probability increased in proportion to V %ratio , that the predictive rectal NTCP was patient-specific, and that the starting point of IMRT optimization for the given patient might be different. The PDF of the rectal NTCP was obtained automatically for each group except that the smoothness of the probability distribution increased with increasing number of data and with increasing window width. We showed that during the prostate IMRT optimization, the patient-specific dose constraints could be automatically generated and that our method could reduce the IMRT optimization time as well as maintain the

  8. Dosimetric study comparing intensity modulated and conformal pelvic radiotherapy boost plans in locally advanced cancer cervix in NCI-Cairo

    Institute of Scientific and Technical Information of China (English)

    Mohamed Mahmoud; Hesham A. EL-Hossiny; Nashaat A. Diab; Mahmoud Shosha

    2013-01-01

    Objective: This study was to compare 5 field conformal technique to the intensity modulated radiotherapy (IMRT) 8 fields technique in boosting locally advanced cancer cervix cases after external beam radiotherapy with respect to target volume coverage and dose to normal tissues. Methods: We conducted a single institutional comparative dosimetric analysis of 10 patients with cancer cervix who was presented to radiotherapy department in National Cancer Institute, Cairo in period between June 2012 to September 2012 and received a CRT boost in the place of planned brachytherapy after large field pelvic radiotherapy (PRT) with concurrent chemotherapy were retrospectively identified. All tumors were situated in the low central pelvis. Two plans were done for every patient; one using the 8 fields IMRT and the second one using 5 fields' 3DCRT the two techniques were then compared using dose volume histogram (DVH) analysis for the PTV, bladder, rectum and both femoral heads. Results: Comparing different DVHs, it was found that the planning target volume (PTV) was adequately covered in both plans while it was demonstrates that the 8 fields IMRT technique carried less doses reaching OARs (rectum, bladder, both femoral heads). Conclusion: From the present study, it is concluded that IMRT technique spared more efficiently OARs than CRT technique but both techniques covered the PTV adequately so whenever possible IMRT technique should be used.

  9. SU-E-T-07: 4DCT Robust Optimization for Esophageal Cancer Using Intensity Modulated Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Liao, L [Proton Therapy Center, UT MD Anderson Cancer Center, Houston, TX (United States); Department of Industrial Engineering, University of Houston, Houston, TX (United States); Yu, J; Zhu, X; Li, H; Zhang, X [Proton Therapy Center, UT MD Anderson Cancer Center, Houston, TX (United States); Li, Y [Proton Therapy Center, UT MD Anderson Cancer Center, Houston, TX (United States); Varian Medical Systems, Houston, TX (United States); Lim, G [Department of Industrial Engineering, University of Houston, Houston, TX (United States)

    2015-06-15

    Purpose: To develop a 4DCT robust optimization method to reduce the dosimetric impact from respiratory motion in intensity modulated proton therapy (IMPT) for esophageal cancer. Methods: Four esophageal cancer patients were selected for this study. The different phases of CT from a set of 4DCT were incorporated into the worst-case dose distribution robust optimization algorithm. 4DCT robust treatment plans were designed and compared with the conventional non-robust plans. Result doses were calculated on the average and maximum inhale/exhale phases of 4DCT. Dose volume histogram (DVH) band graphic and ΔD95%, ΔD98%, ΔD5%, ΔD2% of CTV between different phases were used to evaluate the robustness of the plans. Results: Compare to the IMPT plans optimized using conventional methods, the 4DCT robust IMPT plans can achieve the same quality in nominal cases, while yield a better robustness to breathing motion. The mean ΔD95%, ΔD98%, ΔD5% and ΔD2% of CTV are 6%, 3.2%, 0.9% and 1% for the robustly optimized plans vs. 16.2%, 11.8%, 1.6% and 3.3% from the conventional non-robust plans. Conclusion: A 4DCT robust optimization method was proposed for esophageal cancer using IMPT. We demonstrate that the 4DCT robust optimization can mitigate the dose deviation caused by the diaphragm motion.

  10. Dosimetric study of volumetric arc modulation with RapidArc and intensity-modulated radiotherapy in patients with cervical cancer and comparison with 3-dimensional conformal technique for definitive radiotherapy in patients with cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Guy, Jean-Baptiste [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France); Falk, Alexander T. [Department of Radiation Oncology, Centre Antoine Lacassagne, Nice (France); Auberdiac, Pierre [Department of Radiation Oncology, Clinique Claude Bernard, Albi (France); Cartier, Lysian; Vallard, Alexis [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France); Ollier, Edouard [Department of Pharmacology-Toxicology, Centre Hospitalier Universitaire de Saint-Etienne, Saint-Priest en Jarez (France); Trone, Jane-Chloé; Khodri, Moustapha [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France); Chargari, Cyrus [Department of Radiation Oncology, Hôpital d’instruction de Armées du Val-de-Grâce, Paris (France); Magné, Nicolas, E-mail: nicolas.magne@icloire.fr [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France)

    2016-04-01

    Introduction: For patients with cervical cancer, intensity-modulated radiation therapy (IMRT) improves target coverage and allows dose escalation while reducing the radiation dose to organs at risk (OARs). In this study, we compared dosimetric parameters among 3-dimensional conformal radiotherapy (3D-CRT), “step-and-shoot” IMRT, and volumetric intensity-modulated arc radiotherapy (VMAT) in a series of patients with cervical cancer receiving definitive radiotherapy. Computed tomography (CT) scans of 10 patients with histologically proven cervical cancer treated with definitive radiation therapy (RT) from December 2008 to March 2010 at our department were selected for this study. The gross tumor volume (GTV) and clinical target volume (CTV) were delineated following the guidelines of the Gyn IMRT consortium that included cervix, uterus, parametrial tissues, and the pelvic nodes including presacral. The median age was 57 years (range: 30 to 85 years). All 10 patients had squamous cell carcinoma with Federation of Gynecology and Obstetrics (FIGO) stage IB-IIIB. All patients were treated by VMAT. OAR doses were significantly reduced for plans with intensity-modulated technique compared with 3D-CRT except for the dose to the vagina. Between the 2 intensity-modulated techniques, significant difference was observed for the mean dose to the small intestine, to the benefit of VMAT (p < 0.001). There was no improvement in terms of OARs sparing for VMAT although there was a tendency for a slightly decreased average dose to the rectum: − 0.65 Gy but not significant (p = 0.07). The intensity modulation techniques have many advantages in terms of quality indexes, and particularly OAR sparing, compared with 3D-CRT. Following the ongoing technologic developments in modern radiotherapy, it is essential to evaluate the intensity-modulated techniques on prospective studies of a larger scale.

  11. A dosimetric comparison of 3D conformal vs intensity modulated vs volumetric arc radiation therapy for muscle invasive bladder cancer

    Directory of Open Access Journals (Sweden)

    Foroudi Farshad

    2012-07-01

    Full Text Available Abstract Background To compare 3 Dimensional Conformal radiotherapy (3D-CRT with Intensity Modulated Radiotherapy (IMRT with Volumetric-Modulated Arc Therapy (VMAT for bladder cancer. Methods Radiotherapy plans for 15 patients with T2-T4N0M0 bladder cancer were prospectively developed for 3-DCRT, IMRT and VMAT using Varian Eclipse planning system. The same radiation therapist carried out all planning and the same clinical dosimetric constraints were used. 10 of the patients with well localised tumours had a simultaneous infield boost (SIB of the primary tumour planned for both IMRT and VMAT. Tumour control probabilities and normal tissue complication probabilities were calculated. Results Mean planning time for 3D-CRT, IMRT and VMAT was 30.0, 49.3, and 141.0 minutes respectively. The mean PTV conformity (CI index for 3D-CRT was 1.32, for IMRT 1.05, and for VMAT 1.05. The PTV Homogeneity (HI index was 0.080 for 3D-CRT, 0.073 for IMRT and 0.086 for VMAT. Tumour control and normal tissue complication probabilities were similar for 3D-CRT, IMRT and VMAT. The mean monitor units were 267 (range 250–293 for 3D-CRT; 824 (range 641–1083 for IMRT; and 403 (range 333–489 for VMAT (P  Conclusions VMAT is associated with similar dosimetric advantages as IMRT over 3D-CRT for muscle invasive bladder cancer. VMAT is associated with faster delivery times and less number of mean monitor units than IMRT. SIB is feasible in selected patients with localized tumours.

  12. Australasian Gastrointestinal Trials Group (AGITG) Contouring Atlas and Planning Guidelines for Intensity-Modulated Radiotherapy in Anal Cancer

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    Ng, Michael, E-mail: mng@radoncvic.com.au [Radiation Oncology Victoria, Victoria (Australia); Leong, Trevor [Department of Radiation Oncology, Peter MacCallum Cancer Centre, Victoria (Australia); University of Melbourne (Australia); Chander, Sarat; Chu, Julie [Department of Radiation Oncology, Peter MacCallum Cancer Centre, Victoria (Australia); Kneebone, Andrew [Department of Radiation Oncology, Northern Sydney Cancer Centre, Royal North Shore Hospital, NSW (Australia); University of Sydney (Australia); Carroll, Susan [Department of Radiation Oncology, Sydney Cancer Centre, Royal Prince Alfred Hospital, NSW (Australia); University of Sydney (Australia); Wiltshire, Kirsty [Department of Radiation Oncology, Peter MacCallum Cancer Centre, Victoria (Australia); Ngan, Samuel [Department of Radiation Oncology, Peter MacCallum Cancer Centre, Victoria (Australia); University of Melbourne (Australia); Kachnic, Lisa [Department of Radiation Oncology, Boston Medical Center, Boston University School of Medicine, Boston, MA (United States)

    2012-08-01

    Purpose: To develop a high-resolution target volume atlas with intensity-modulated radiotherapy (IMRT) planning guidelines for the conformal treatment of anal cancer. Methods and Materials: A draft contouring atlas and planning guidelines for anal cancer IMRT were prepared at the Australasian Gastrointestinal Trials Group (AGITG) annual meeting in September 2010. An expert panel of radiation oncologists contoured an anal cancer case to generate discussion on recommendations regarding target definition for gross disease, elective nodal volumes, and organs at risk (OARs). Clinical target volume (CTV) and planning target volume (PTV) margins, dose fractionation, and other IMRT-specific issues were also addressed. A steering committee produced the final consensus guidelines. Results: Detailed contouring and planning guidelines and a high-resolution atlas are provided. Gross tumor and elective target volumes are described and pictorially depicted. All elective regions should be routinely contoured for all disease stages, with the possible exception of the inguinal and high pelvic nodes for select, early-stage T1N0. A 20-mm CTV margin for the primary, 10- to 20-mm CTV margin for involved nodes and a 7-mm CTV margin for the elective pelvic nodal groups are recommended, while respecting anatomical boundaries. A 5- to 10-mm PTV margin is suggested. When using a simultaneous integrated boost technique, a dose of 54 Gy in 30 fractions to gross disease and 45 Gy to elective nodes with chemotherapy is appropriate. Guidelines are provided for OAR delineation. Conclusion: These consensus planning guidelines and high-resolution atlas complement the existing Radiation Therapy Oncology Group (RTOG) elective nodal ano-rectal atlas and provide additional anatomic, clinical, and technical instructions to guide radiation oncologists in the planning and delivery of IMRT for anal cancer.

  13. Quality of life after intensity-modulated radiotherapy for prostate cancer with a hydrogel spacer. Matched-pair analysis

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    Pinkawa, M.; Piroth, M.D.; Holy, R.; Escobar-Corral, N.; Caffaro, M.; Djukic, V.; Klotz, J.; Eble, M.J. [RWTH Aachen Univ. (Germany). Dept. of Radiation Oncology

    2012-10-15

    Background: Hydrogel spacer is an innovative method to protect the rectal wall during prostate cancer radiotherapy. Clinical effects are not well known. Methods: Patients have been surveyed before, at the last day, and 2-3 months after radiotherapy using a validated questionnaire (Expanded Prostate Cancer Index Composite). Median dose to the prostate in the spacer subgroup (SP) was 78 Gy in 2 Gy fractions. The results were independently compared with two matched-pair subgroups (treated conventionally without spacer): 3D conformal 70.2 Gy in 1.8 Gy fractions (3DCRT) and intensity-modulated radiotherapy (IMRT) 76 Gy in 2 Gy fractions. There were 28 patients in each of the three groups. Results: Baseline mean bowel bother scores were 96 points in all subgroups. Similar mean changes (SP 16, 3DCRT 14, IMRT 17 points) were observed at the end of radiotherapy. The smallest difference resulted in the spacer subgroup 2-3 months after radiotherapy (SP 2, 3DCRT 8, IMRT 6 points). Bowel bother scores were only significantly different in comparison to baseline levels in the spacer subgroup. The percentage of patients reporting moderate/big bother with specific symptoms did not increase for any item (urgency, frequency, diarrhoea, incontinence, bloody stools, pain). Conclusion: Moderate bowel quality-of-life changes can be expected during radiotherapy irrespective of spacer application or total dose. Advantages with a spacer can be expected a few weeks after treatment. (orig.)

  14. A prospective comparison of acute intestinal toxicity following whole pelvic versus small field intensity-modulated radiotherapy for prostate cancer

    Science.gov (United States)

    Kim, Yeon Joo; Park, Jin-hong; Yun, In-Ha; Kim, Young Seok

    2016-01-01

    Purpose To compare the acute intestinal toxicity of whole pelvic (WP) and small field (SF) intensity-modulated radiotherapy (IMRT) for prostate cancer using dosimetric and metabolic parameters as well as clinical findings. Methods Patients who received IMRT in either a definitive or postoperative setting were prospectively enrolled. Target volume and organs at risk including intestinal cavity (IC) were delineated in every patient by a single physician. The IC volume that received a 10–50 Gy dose at 5-Gy intervals (V10–V50) and the percentage of irradiated volume as a fraction of total IC volume were calculated. Plasma citrulline levels, as an objective biological marker, were checked at three time points: baseline and after exposure to 30 Gy and 60 Gy. Results Of the 41 patients, only six experienced grade 1 acute intestinal toxicity. Although all dose–volume parameters were significantly worse following WP than SF IMRT, there was no statistically significant relationship between these dosimetric parameters and clinical symptoms. Plasma citrulline levels did not show a serial decrease by radiotherapy volume difference (WP versus SF) and were not relevant to the irradiated doses. Conclusion Given that WP had comparable acute intestinal toxicities to those associated with SF, WP IMRT appears to be a feasible approach for the treatment of prostate cancer despite dosimetric disadvantages. PMID:27022287

  15. Long-term results of forward intensity-modulated radiation therapy for patients with early-stage breast cancer

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    Ha, Boram; Suh, Hyun Suk; Lee, Ji Hae; Lee, Kyung Ja; Lee, Rena; Moon, Byung In [Ewha Womans University College of Medicine, Seoul (Korea, Republic of)

    2013-12-15

    To observe long-term clinical outcomes for patients with early-stage breast cancer treated with forward intensity-modulated radiation therapy (IMRT), including local control and clinical toxicities. We retrospectively analyzed a total of 214 patients with stage I-II breast cancer who were treated with breast conserving surgery followed by adjuvant breast radiation therapy between 2001 and 2008. All patients were treated using forward IMRT. The whole breast was irradiated to a dose of 50 to 50.4 Gy followed by an 8 to 12 Gy electron boost to the surgical bed. The median age was 46 years (range, 21 to 82 years) and the medial follow-up time was 7.3 years (range, 2.4 to 11.7 years). Stage T1 was 139 (65%) and T2 was 75 (35%), respectively. Ipsilateral breast recurrence was observed in 3 patients. The 5- and 10-year local control rates were 99.1% and 97.8%, respectively. The cosmetic outcome was evaluated according to the Harvard scale and 89.4% of patients were scored as excellent or good. The whole breast radiation therapy as an adjuvant treatment using a forward IMRT technique showed excellent long-term local control as well as favorable outcomes of toxicity and cosmesis.

  16. Multimodal hypoxia imaging and intensity modulated radiation therapy for unresectable non-small-cell lung cancer: the HIL trial

    Directory of Open Access Journals (Sweden)

    Askoxylakis Vasileios

    2012-09-01

    Full Text Available Abstract Background Radiotherapy, preferably combined with chemotherapy, is the treatment standard for locally advanced, unresectable non-small cell lung cancer (NSCLC. The tumor response to different therapy protocols is variable, with hypoxia known to be a major factor that negatively influences treatment effectiveness. Visualisation of tumor hypoxia prior to the use of modern radiation therapy strategies, such as intensity modulated radiation therapy (IMRT, might allow optimized dose applications to the target volume, leading to improvement of therapy outcome. 18 F-fluoromisonidazole dynamic positron emission tomography and computed tomography (18 F-FMISO dPET-CT and functional magnetic resonance imaging (functional MRI are attractive options for imaging tumor hypoxia. Methods/design The HIL trial is a single centre study combining multimodal hypoxia imaging with 18 F-FMISO dPET-CT and functional MRI, with intensity modulated radiation therapy (IMRT in patients with inoperable stage III NSCLC. 15 patients will be recruited in the study. All patients undergo initial FDG PET-CT and serial 18 F-FMISO dPET-CT and functional MRI before treatment, at week 5 of radiotherapy and 6 weeks post treatment. Radiation therapy is performed as inversely planned IMRT based on 4D-CT. Discussion Primary objectives of the trial are to characterize the correlation of 18 F-FMISO dPET-CT and functional MRI for tumor hypoxia imaging in NSCLC and evaluate possible effects of radiation therapy on tumor re-oxygenation. Further objectives include the generation of data regarding the prognostic value of 18 F-FMISO dPET-CT and functional MRI for locoregional control, progression free survival and overall survival of NSCLC treated with IMRT, which will form the basis for larger clinical trials focusing on possible interactions between tumor oxygenation and radiotherapy outcome. Trial registration The ClinicalTrials.gov protocol ID is NCT01617980

  17. Cervix carcinomas: place of intensity-modulated radiotherapy; Les cancers du col uterin: place de la radiotherapie avec modulation d'intensite

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    Barillot, I. [Centre Regional Universitaire de Cancerologie H.S.-Kaplan, Hopital Bretonneau, CHU de Tours, 37 - Tours (France); Universite Francois-Rabelais, 37 - Tours (France)

    2009-10-15

    While indications of modulated intensity radiation therapy (I.M.R.T.) are perfectly defined in head and neck and prostate cancer patients, this technique remains under evaluation for gynecologic tumours. The implementation of conformal three dimensional radiotherapy in the late 1990 has been the first important step for optimisation of treatment of cervix carcinomas, as it permitted a better target coverage with a significant reduction of the bladder dose. However, this technique often leads to an irradiation of a larger volume of rectum in locally advanced stages and could only spare a limited amount of intestine. I.R.M.T. is one of the optimisation methods potentially efficient for a better sparing of digestive tract during irradiation of cervix carcinomas. The aim of this literature review is to provide the arguments supporting this hypothesis, and to define the place of this technique for dose escalation. (authors)

  18. Comparison of dose contribution to normal pelvic tissues among conventional, conformal and intensity-modulated radiotherapy techniques in prostate cancer

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    Yungan Tao; Lefkopoulos, Dimitri; Ibrahima, Diallo; Bridier, Andre; Polizzi, Maria del Pilar; Wibault, Pierre; Crevoisier, Renaud de; Arriagada, Rodrigo; Bourhis, Jean (Dept. of Radiotherapy, Institut Gustave-Roussy, Villejuif (France))

    2008-03-15

    High-energy external radiotherapy has become one of the most common treatment in localized prostate cancer. We compared the difference of dose distribution, mainly at the 5-30 Gy dose level, in the irradiated pelvic volume among three modalities of radiotherapy for patients with prostate cancer: conventional, conformal and intensity-modulated radiotherapy (IMRT). We selected six patients with prostate cancer treated by conformal radiotherapy at the doses of 46 Gy to PTVN (prostate and seminal vesicles), and 70 Gy to PTV-T (prostate). The conventional technique: an 8-field arrangement was used; the conformal technique 4 fields with a boost through 6 fields. For IMRT, a five-beam arrangement was used. Dose-volume histograms (DVH) were analyzed and compared among the three techniques. The IMRT technique significantly increased the pelvic volume covered by the isodose surfaces below 15 Gy as compared with the conventional and conformal techniques. The mean absolute increase for the pelvic volume included between 5-30 Gy for the IMRT technique, was about 2 900 ml as compared with the conventional technique. However, IMRT significantly reduced the irradiated volume of the rectum in the dose range of 5 to 40 Gy, also significantly reduced the irradiated volume of bladder and femoral heads, and obtained a similar or improved isodose distribution in the PTVs. In addition, the use of IMRT slightly increased the relative dose delivered to the body volume outside the pelvis, as estimated by the use of specific software. A long-term follow-up will be needed to evaluate potential late treatment complications related to the use of IMRT and the low or moderate irradiation dose level obtained in the pelvis and in the whole body

  19. SU-E-T-617: Plan Quality Estimation of Intensity-Modulated Radiotherapy Cases for Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Koo, J; Yoon, M [Korea University, Seoul (Korea, Republic of); Chung, W; Kim, D [Kyung Hee University Hospital at Gangdong, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: To estimate the planning quality of intensity-modulated radiotherapy in lung cancer cases and to provide preliminary data for the development of a planning quality assurance algorithm. Methods: 42 IMRT plans previously used in cases of solitary lung cancers were collected. Organs in or near the thoracic cavity, such as lung (ipsilateral, contralateral), heart, liver, esophagus, cord and bronchus were considered as organs at risk (OARs) in this study. The coverage index (CVI), conformity index (CI), homogeneity index (HI), volume, irregularity (standard deviation of center-surface distance) were used to compare PTV dose characteristics. The effective uniform dose (EUD), V10Gy, and V20Gy of the OARs were used to compare OAR dose characteristics. Results: Average CVI, CI, HI values were 0.9, 0.8, 0.1, respectively. CVI and CI had narrow Gaussian distribution curves without a singular value, but one case had a relatively high (0.25) HI because of location and irregular shape (Irregularity of 18.5 when average was 12.5) of PTV. EUDs tended to decrease as OAR-PTV distance increased and OAR-PTV overlap volume decreased. Conclusion: This work indicates the potential for significant plan quality deviation of similar lung cancer cases. Considering that this study were from a single department, differences in the treatment results for a given patient would be much more pronounced if multiple departments (and therefore more planners) were involved. Therefore, further examination of QA protocols is needed to reduce deviations in radiation treatment planning.

  20. Treatment outcome of localized prostate cancer by 70 Gy hypofractionated intensity-modulated radiotherapy with a customized rectal balloon

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    Kim, Hyun Jung; Kim, Jun Won; Hong, Sung Joon; Rha, Koon Ho; Lee, Chang Geol; Yang, Seung Choul; Choi, Young Deuk; Suh, Chang Ok; Cho, Jae Ho [Yonsei Cancer Center, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2014-09-15

    We aimed to analyze the treatment outcome and long-term toxicity of 70 Gy hypofractionated intensity-modulated radiotherapy (IMRT) for localized prostate cancer using a customized rectal balloon. We reviewed medical records of 86 prostate cancer patients who received curative radiotherapy between January 2004 and December 2011 at our institution. Patients were designated as low (12.8%), intermediate (20.9%), or high risk (66.3%). Thirty patients received a total dose of 70 Gy in 28 fractions over 5 weeks via IMRT (the Hypo-IMRT group); 56 received 70.2 Gy in 39 fractions over 7 weeks via 3-dimensional conformal radiotherapy (the CF-3DRT group, which served as a reference for comparison). A customized rectal balloon was placed in Hypo-IMRT group throughout the entire radiotherapy course. Androgen deprivation therapy was administered to 47 patients (Hypo-IMRT group, 17; CF-3DRT group, 30). Late genitourinary (GU) and gastrointestinal (GI) toxicity were evaluated according to the Radiation Therapy Oncology Group criteria. The median follow-up period was 74.4 months (range, 18.8 to 125.9 months). The 5-year actuarial biochemical relapse-free survival rates for low-, intermediate-, and high-risk patients were 100%, 100%, and 88.5%, respectively, for the Hypo-IMRT group and 80%, 77.8%, and 63.6%, respectively, for the CF-3DRT group (p < 0.046). No patient presented with acute or late GU toxicity > or =grade 3. Late grade 3 GI toxicity occurred in 2 patients (3.6%) in the CF-3DRT group and 1 patient (3.3%) in the Hypo-IMRT group. Hypo-IMRT with a customized rectal balloon resulted in excellent biochemical control rates with minimal toxicity in localized prostate cancer patients.

  1. Intensity modulated radiotherapy for localized prostate cancer: rigid compliance to dose-volume constraints as a warranty of acceptable toxicity?

    Directory of Open Access Journals (Sweden)

    Moreira Frederico R

    2007-01-01

    Full Text Available Abstract Background To report the toxicity after intensity modulated radiotherapy (IMRT for patients with localized prostate cancer, as a sole treatment or after radical prostatectomy. Methods Between August 2001 and December 2003, 132 patients with prostate cancer were treated with IMRT and 125 were evaluable to acute and late toxicity analysis, after a minimum follow-up time of one year. Clinical and treatment data, including normal tissue dose-volume histogram (DVH constraints, were reviewed. Gastro-intestinal (GI and genito-urinary (GU signs and symptoms were evaluated according to the Radiation Therapy Oncology Group (RTOG toxicity scales. Median prescribed dose was 76 Gy. Median follow-up time was of 26.1 months. Results From the 125 patients, 73 (58.4% presented acute Grade 1 or Grade 2 GI and 97 (77.2% presented acute Grade 1 or Grade 2 GU toxicity. Grade 3 GI acute toxicity occurred in only 2 patients (1.6% and Grade 3 GU acute toxicity in only 3 patients (2.4%. Regarding Grade 1 and 2 late toxicity, 26 patients (20.8% and 21 patients (16.8% presented GI and GU toxicity, respectively. Grade 2 GI late toxicity occurred in 6 patients (4.8% and Grade 2 GU late toxicity in 4 patients (3.2%. None patient presented any Grade 3 or higher late toxicity. Non-conformity to DVH constraints occurred in only 11.2% of treatment plans. On univariate analysis, no significant risk factor was identified for Grade 2 GI late toxicity, but mean dose delivered to the PTV was associated to higher Grade 2 GU late toxicity (p = 0.042. Conclusion IMRT is a well tolerable technique for routine treatment of localized prostate cancer, with short and medium-term acceptable toxicity profiles. According to the data presented here, rigid compliance to DHV constraints might prevent higher incidences of normal tissue complication.

  2. Helical tomotherapy based intensity modulated radiotherapy for the management of difficult clinical situations in breast cancer

    Directory of Open Access Journals (Sweden)

    Animesh Saha

    2015-01-01

    Full Text Available Helical tomotherapy (HT can achieve a homogenous dose distribution in the planning target volume while minimizing the dose to the organ at risk. Tomotherapy has been used for complex breast cancer radiotherapy including bilateral breast irradiation, pectus excavatum, and internal mammary chain (IMC nodal irradiation. This report details our experience of using HT in breast cancers in newer clinical indications. Three patients with SCF nodal involvement (case 1, high level III axillary node recurrence (case 2, and composite irradiation of SCF, IMC, and whole breast (case 3 were treated using brachial plexus sparing HT. It was possible to boost the SCF, reirradiate the high level III axillary nodal recurrence and treat complex volume of breast, SCF, and IMC with acceptable and safe dose volume histogram constraints and with good homogeneity and conformity indices. The treatment was successful in controlling disease locoregionally at a 15 months follow-up. No patients reported symptoms suggestive of brachial plexopathy

  3. Dosimetric effects of weight loss or gain during volumetric modulated arc therapy and intensity-modulated radiation therapy for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Pair, Matthew L. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Du, Weiliang [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Rojas, Hector D.; Kanke, James E.; McGuire, Sean E.; Lee, Andrew K.; Kuban, Deborah A. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Kudchadker, Rajat J., E-mail: rkudchad@mdanderson.org [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX (United States)

    2013-10-01

    Weight loss or gain during the course of radiation therapy for prostate cancer can alter the planned dose to the target volumes and critical organs. Typically, source-to-surface distance (SSD) measurements are documented by therapists on a weekly basis to ensure that patients' exterior surface and isocenter-to-skin surface distances remain stable. The radiation oncology team then determines whether the patient has undergone a physical change sufficient to require a new treatment plan. The effect of weight change (SSD increase or decrease) on intensity-modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT) dosimetry is not well known, and it is unclear when rescanning or replanning is needed. The purpose of this study was to determine the effects of weight change (SSD increase or decrease) on IMRT or VMAT dose delivery in patients with prostate cancer and to determine the SSD change threshold for replanning. Whether IMRT or VMAT provides better dose stability under weight change conditions was also determined. We generated clinical IMRT and VMAT prostate and seminal vesicle treatment plans for varying SSDs for 10 randomly selected patients with prostate cancer. The differences due to SSD change were quantified by a specific dose change for a specified volume of interest. The target mean dose, decreased or increased by 2.9% per 1-cm SSD decrease or increase in IMRT and by 3.6% in VMAT. If the SSD deviation is more than 1 cm, the radiation oncology team should determine whether to continue treatment without modifications, to adjust monitor units, or to resimulate and replan.

  4. 3D-conformal-intensity modulated radiotherapy with compensators for head and neck cancer: clinical results of normal tissue sparing

    Directory of Open Access Journals (Sweden)

    Koscielny Sven

    2006-06-01

    Full Text Available Abstract Background To investigate the potential of parotic gland sparing of intensity modulated radiotherapy (3D-c-IMRT performed with metallic compensators for head and neck cancer in a clinical series by analysis of dose distributions and clinical measures. Materials and methods 39 patients with squamous cell cancer of the head and neck irradiated using 3D-c-IMRT were evaluable for dose distribution within PTVs and at one parotid gland and 38 patients for toxicity analysis. 10 patients were treated primarily, 29 postoperatively, 19 received concomittant cis-platin based chemotherapy, 20 3D-c-IMRT alone. Initially the dose distribution was calculated with Helax ® and photon fluence was modulated using metallic compensators made of tin-granulate (n = 22. Later the dose distribution was calculated with KonRad ® and fluence was modified by MCP 96 alloy compensators (n = 17. Gross tumor/tumor bed (PTV 1 was irradiated up to 60–70 Gy, [5 fractions/week, single fraction dose: 2.0–2.2 (simultaneously integrated boost], adjuvantly irradiated bilateral cervical lymph nodes (PTV 2 with 48–54 Gy [single dose: 1.5–1.8]. Toxicity was scored according the RTOG scale and patient-reported xerostomia questionnaire (XQ. Results Mean of the median doses at the parotid glands to be spared was 25.9 (16.3–46.8 Gy, for tin graulate 26 Gy, for MCP alloy 24.2 Gy. Tin-granulate compensators resulted in a median parotid dose above 26 Gy in 10/22, MCP 96 alloy in 0/17 patients. Following acute toxicities were seen (°0–2/3: xerostomia: 87%/13%, dysphagia: 84%/16%, mucositis: 89%/11%, dermatitis: 100%/0%. No grade 4 reaction was encountered. During therapy the XQ forms showed °0–2/3: 88%/12%. 6 months postRT chronic xerostomia °0–2/3 was observed in 85%/15% of patients, none with °4 xerostomia. Conclusion 3D-c-IMRT using metallic compensators along with inverse calculation algorithm achieves sufficient parotid gland sparing in virtually all advanced

  5. SU-E-T-358: Empirical Beam Angle Optimization for Lung Cancer Intensity Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Doozan, B [Florida Atlantic University (United States); Pella, S [South Florida Radiation Oncology, Boca Raton, FL (United States)

    2015-06-15

    Purpose: Creating an improved BAO can decrease the amount of time a dosimetrist spends on making a treatment plan, improve the treatment quality and enhance the tools an inexperienced dosimetrist can use to develop planning techniques. Methods: Using empirical data created by experienced dosimetrists from 69 patients treated for lung cancer, the most frequently used gantry angles were applied to four different regions in each lung to gather an optimal set of fields that could be used to treat future lung cancer patients. This method, given the moniker FAU BAO, is compared in 7 plans created with the Eclipse BAO choosing 5 fields and 9 fields. Results: The results show that the conformality index improved by 30% or 3% when using the 5 and 9 fields. The conformation number was better by 12% from the 5 fields and 9% from the 9 fields. The organs at risk (OAR) were overall more protected to produce fewer nonstochastic effects from the radiation treatment with the FAU BAO. Conclusion: Empirical methods for beam angle optimization is a viable method for IMRT treatment planning techniques.

  6. Comparison of testicular dose delivered by intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) in patients with prostate cancer.

    Science.gov (United States)

    Martin, Jeffrey M; Handorf, Elizabeth A; Price, Robert A; Cherian, George; Buyyounouski, Mark K; Chen, David Y; Kutikov, Alexander; Johnson, Matthew E; Ma, Chung-Ming Charlie; Horwitz, Eric M

    2015-01-01

    A small decrease in testosterone level has been documented after prostate irradiation, possibly owing to the incidental dose to the testes. Testicular doses from prostate external beam radiation plans with either intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT) were calculated to investigate any difference. Testicles were contoured for 16 patients being treated for localized prostate cancer. For each patient, 2 plans were created: 1 with IMRT and 1 with VMAT. No specific attempt was made to reduce testicular dose. Minimum, maximum, and mean doses to the testicles were recorded for each plan. Of the 16 patients, 4 received a total dose of 7800 cGy to the prostate alone, 7 received 8000 cGy to the prostate alone, and 5 received 8000 cGy to the prostate and pelvic lymph nodes. The mean (range) of testicular dose with an IMRT plan was 54.7 cGy (21.1 to 91.9) and 59.0 cGy (25.1 to 93.4) with a VMAT plan. In 12 cases, the mean VMAT dose was higher than the mean IMRT dose, with a mean difference of 4.3 cGy (p = 0.019). There was a small but statistically significant increase in mean testicular dose delivered by VMAT compared with IMRT. Despite this, it unlikely that there is a clinically meaningful difference in testicular doses from either modality.

  7. Comparison of testicular dose delivered by intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) in patients with prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Jeffrey M. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Handorf, Elizabeth A. [Department of Biostatistics, Fox Chase Cancer Center, Philadelphia, PA (United States); Price, Robert A.; Cherian, George [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Buyyounouski, Mark K. [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Chen, David Y.; Kutikov, Alexander [Department of Urologic Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Johnson, Matthew E.; Ma, Chung-Ming Charlie [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Horwitz, Eric M., E-mail: eric.horwitz@fccc.edu [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States)

    2015-10-01

    A small decrease in testosterone level has been documented after prostate irradiation, possibly owing to the incidental dose to the testes. Testicular doses from prostate external beam radiation plans with either intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT) were calculated to investigate any difference. Testicles were contoured for 16 patients being treated for localized prostate cancer. For each patient, 2 plans were created: 1 with IMRT and 1 with VMAT. No specific attempt was made to reduce testicular dose. Minimum, maximum, and mean doses to the testicles were recorded for each plan. Of the 16 patients, 4 received a total dose of 7800 cGy to the prostate alone, 7 received 8000 cGy to the prostate alone, and 5 received 8000 cGy to the prostate and pelvic lymph nodes. The mean (range) of testicular dose with an IMRT plan was 54.7 cGy (21.1 to 91.9) and 59.0 cGy (25.1 to 93.4) with a VMAT plan. In 12 cases, the mean VMAT dose was higher than the mean IMRT dose, with a mean difference of 4.3 cGy (p = 0.019). There was a small but statistically significant increase in mean testicular dose delivered by VMAT compared with IMRT. Despite this, it unlikely that there is a clinically meaningful difference in testicular doses from either modality.

  8. Acute and late toxicity in prostate cancer patients treated by dose escalated intensity modulated radiation therapy and organ tracking

    Directory of Open Access Journals (Sweden)

    Behrensmeier Frank

    2008-10-01

    Full Text Available Abstract Background To report acute and late toxicity in prostate cancer patients treated by dose escalated intensity-modulated radiation therapy (IMRT and organ tracking. Methods From 06/2004 to 12/2005 39 men were treated by 80 Gy IMRT along with organ tracking. Median age was 69 years, risk of recurrence was low 18%, intermediate 21% and high in 61% patients. Hormone therapy (HT was received by 74% of patients. Toxicity was scored according to the CTC scale version 3.0. Median follow-up (FU was 29 months. Results Acute and maximal late grade 2 gastrointestinal (GI toxicity was 3% and 8%, late grade 2 GI toxicity dropped to 0% at the end of FU. No acute or late grade 3 GI toxicity was observed. Grade 2 and 3 pre-treatment genitourinary (GU morbidity (PGUM was 20% and 5%. Acute and maximal late grade 2 GU toxicity was 56% and 28% and late grade 2 GU toxicity decreased to 15% of patients at the end of FU. Acute and maximal late grade 3 GU toxicity was 8% and 3%, respectively. Decreased late ≥ grade 2 GU toxicity free survival was associated with higher age (P = .025, absence of HT (P = .016 and higher PGUM (P Discussion GI toxicity rates after IMRT and organ tracking are excellent, GU toxicity rates are strongly related to PGUM.

  9. Forward-planned intensity modulated radiation therapy using a cobalt source: A dosimetric study in breast cancer

    Directory of Open Access Journals (Sweden)

    Savino Cilla

    2013-01-01

    Full Text Available This analysis evaluates the feasibility and dosimetric results of a simplified intensity-modulated radiotherapy (IMRT treatment using a cobalt-therapy unit for post-operative breast cancer. Fourteen patients were included. Three plans per patient were produced by a cobalt-60 source: A standard plan with two wedged tangential beams, a standard tangential plan optimized without the use of wedges and a plan based on the forward-planned "field-in-field" IMRT technique (Co-FinF where the dose on each of the two tangential beams was split into two different segments and the two segments weight was determined with an iterative process. For comparison purposes, a 6-MV photon standard wedged tangential treatment plan was generated. D mean , D 98% , D 2% , V 95% , V 107%, homogeneity, and conformity indices were chosen as parameters for comparison. Co-FinF technique improved the planning target volume dose homogeneity compared to other cobalt-based techniques and reduced maximum doses (D 2% and high-dose volume (V 110% . Moreover, it showed a better lung and heart dose sparing with respect to the standard approach. The higher dose homogeneity may encourage the adoption of accelerated-hypofractionated treatments also with the cobalt sources. This approach can promote the spread of breast conservative treatment in developing countries.

  10. Intensity-modulated radiation therapy for early-stage breast cancer: is it ready for prime time?

    Science.gov (United States)

    Chan, Tabitha Y; Tan, Poh Wee; Tang, Johann I

    2017-01-01

    Whole breast external beam radiotherapy (WBEBRT) is commonly used as an essential arm in the treatment management of women with early-stage breast cancer. Dosimetry planning for conventional WBEBRT typically involves a pair of tangential fields. Advancement in radiation technology and techniques has the potential to improve treatment outcomes with clinically meaningful long-term benefits. However, this advancement must be balanced with safety and improved efficacy. Intensity-modulated radiation therapy (IMRT) is an advanced technique that shows promise in improving the planning process and radiation delivery. Early data on utilizing IMRT for WBEBRT demonstrate more homogenous dose distribution with reduction in organs at risk doses. This translates to toxicities reduction. The two common descriptors for IMRT are forward-planning “fields in field” and inverse planning. Unlike IMRT for other organs, the aim of IMRT for breast planning is to achieve dose homogeneity and not organ conformality. The aim of this paper was to evaluate whether IMRT is ready for prime time based on these three points: 1) workload impact, 2) the clinical impact on the patient’s quality of life, and 3) the appropriateness and applicability to clinical practice.

  11. CIM—Compact intensity modulation

    Science.gov (United States)

    Bleuel, M.; Lang, E.; Gähler, R.; Lal, J.

    2008-07-01

    Compact intensity modulation (CIM), a new method to modulate the intensity of a neutron beam is demonstrated. CIM allows the production of arbitrary signals where the focus point can be chosen and changed without any constraints. A novel feature in this technique compared to spin echo techniques is that the neutron polarization is kept parallel or anti-parallel to the static fields during the passage through the magnetic fields and the beating pattern at the detector is produced by an amplitude modulation (AM) of the adiabatic RF-spin flippers rather than Larmor precession like in neutron spin echo (NSE) instruments; thus, the achievable contrast is very high and the instrument resolution can be changed very quickly. This gives the fascinating possibility at pulsed neutron sources to sweep the modulation frequency of the flippers in order to increase dynamic resolution range during the same neutron pulse.

  12. Intensity-Modulated and Image-Guided Radiotherapy in Patients with Locally Advanced Inoperable Pancreatic Cancer after Preradiation Chemotherapy

    Directory of Open Access Journals (Sweden)

    M. Sinn

    2014-01-01

    Full Text Available Background. Radiotherapy (RT in patients with pancreatic cancer is still a controversial subject and its benefit in inoperable stages of locally advanced pancreatic cancer (LAPC, even after induction chemotherapy, remains unclear. Modern radiation techniques such as image-guided radiotherapy (IGRT and intensity-modulated radiotherapy (IMRT may improve effectiveness and reduce radiotherapy-related toxicities. Methods. Patients with LAPC who underwent radiotherapy after chemotherapy between 09/2004 and 05/2013 were retrospectively analyzed with regard to preradiation chemotherapy (PRCT, modalities of radiotherapy, and toxicities. Progression-free (PFS and overall survival (OS were estimated by Kaplan-Meier curves. Results. 15 (68% women and 7 men (median age 64 years; range 40–77 were identified. Median duration of PRCT was 11.1 months (range 4.3–33.0. Six patients (27% underwent conventional RT and 16 patients (73% advanced IMRT and IGRT; median dosage was 50.4 (range 9–54 Gray. No grade III or IV toxicities occurred. Median PFS (estimated from the beginning of RT was 5.8 months, 2.6 months in the conventional RT group (conv-RT, and 7.1 months in the IMRT/IGRT group (P=0.029; median OS was 11.0 months, 4.2 months (conv-RT, and 14.0 months (IMRT/IGRT; P=0.141. Median RT-specific PFS for patients with prolonged PRCT > 9 months was 8.5 months compared to 5.6 months for PRCT 9 months group, with 19.0 months compared to 8.5 months in the PRCT  <  9 months group (P=0.049. Conclusions. IGRT and IMRT after PRCT are feasible and effective options for patients with LAPC after prolonged preradiation chemotherapy.

  13. Intensity-modulated radiation therapy with concurrent chemotherapy for locally advanced cervical and upper thoracic esophageal cancer

    Institute of Scientific and Technical Information of China (English)

    Shu-Lian Wang; Zhongxing Liao; Helen Liu; Jaffer Ajani; Stephen Swisher; James D Cox; Ritsuko Komaki

    2006-01-01

    AIM: To evaluate the dosimetry, efficacy and toxicity of intensity-modulated radiation therapy (IMRT) and concurrent chemotherapy for patients with locally advanced cervical and upper thoracic esophageal cancer.METHODS: A retrospective study was performed on 7 patients who were definitively treated with IMRT and concurrent chemotherapy. Patients who did not receive IMRT radiation and concurrent chemotherapy were not included in this analysis. IMRT plans were evaluated to assess the tumor coverage and normal tissue avoidance. Treatment response was evaluated and toxicities were assessed.RESULTS: Five- to nine-beam IMRT were used to deliver a total dose of 59.4-66 Gy (median: 64.8 Gy) to the primary tumor with 6-MV photons. The minimum dose received by the planning tumor volume (PTV) of the gross tumor volume boost was 91.2%-98.2% of the prescription dose (standard deviation [SD]: 3.7%-5.7%).tumor volume was 93.8%-104.8% (SD: 4.3%-11.1%)of the prescribed dose. With a median follow-up of 15 mo (range: 3-21 mo), all 6 evaluable patients achieved complete response. Of them, 2 developed local recurrences and 2 had distant metastases, 3 survived with no evidence of disease. After treatment, 2 patients developed esophageal stricture requiring frequent dilation and 1 patient developed tracheal-esophageal fistula.CONCLUSION: Concurrent IMRT and chemotherapy resulted in an excellent early response in patients with locally advanced cervical and upper thoracic esophageal cancer. However, local and distant recurrence and toxicity remain to be a problem. Innovative approaches are needed to improve the outcome.

  14. Cost-Effectiveness Analysis of Intensity Modulated Radiation Therapy Versus 3-Dimensional Conformal Radiation Therapy for Anal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hodges, Joseph C., E-mail: joseph.hodges@utsouthwestern.edu [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Beg, Muhammad S. [Division of Hematology and Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Das, Prajnan [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Meyer, Jeffrey [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States)

    2014-07-15

    Purpose: To compare the cost-effectiveness of intensity modulated radiation therapy (IMRT) and 3-dimensional conformal radiation therapy (3D-CRT) for anal cancer and determine disease, patient, and treatment parameters that influence the result. Methods and Materials: A Markov decision model was designed with the various disease states for the base case of a 65-year-old patient with anal cancer treated with either IMRT or 3D-CRT and concurrent chemotherapy. Health states accounting for rates of local failure, colostomy failure, treatment breaks, patient prognosis, acute and late toxicities, and the utility of toxicities were informed by existing literature and analyzed with deterministic and probabilistic sensitivity analysis. Results: In the base case, mean costs and quality-adjusted life expectancy in years (QALY) for IMRT and 3D-CRT were $32,291 (4.81) and $28,444 (4.78), respectively, resulting in an incremental cost-effectiveness ratio of $128,233/QALY for IMRT compared with 3D-CRT. Probabilistic sensitivity analysis found that IMRT was cost-effective in 22%, 47%, and 65% of iterations at willingness-to-pay thresholds of $50,000, $100,000, and $150,000 per QALY, respectively. Conclusions: In our base model, IMRT was a cost-ineffective strategy despite the reduced acute treatment toxicities and their associated costs of management. The model outcome was sensitive to variations in local and colostomy failure rates, as well as patient-reported utilities relating to acute toxicities.

  15. Hypofractionated Intensity Modulated Radiation Therapy in Combined Modality Treatment for Bladder Preservation in Elderly Patients With Invasive Bladder Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Turgeon, Guy-Anne [Department of Oncology, Division of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Souhami, Luis, E-mail: luis.souhami@muhc.mcgill.ca [Department of Oncology, Division of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Cury, Fabio L.; Faria, Sergio L.; Duclos, Marie [Department of Oncology, Division of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Sturgeon, Jeremy [Department of Medical Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Kassouf, Wassim [Department of Urology, McGill University Health Centre, Montreal, Quebec (Canada)

    2014-02-01

    Purpose/Objective(s): To review our experience with bladder-preserving trimodality treatment (TMT) using hypofractionated intensity modulated radiation therapy (IMRT) for the treatment of elderly patients with muscle-invasive bladder cancer. Methods and Materials: Retrospective study of elderly patients treated with TMT using hypofractionated IMRT (50 Gy in 20 fractions) with concomitant weekly radiosensitizing chemotherapy. Eligibility criteria were as follows: age ≥70 years, a proven diagnosis of muscle-invasive transitional cell bladder carcinoma, stage T2-T3N0M0 disease, and receipt of TMT with curative intent. Response rate was assessed by cystoscopic evaluation and bladder biopsy. Results: 24 patients with a median age of 79 years were eligible. A complete response was confirmed in 83% of the patients. Of the remaining patients, 1 of them underwent salvage cystectomy, and no disease was found in the bladder on histopathologic assessment. After a median follow-up time of 28 months, of the patients with a complete response, 2 patients had muscle-invasive recurrence, 1 experienced locoregional failure, and 3 experienced distant metastasis. The overall and cancer-specific survival rates at 3 years were 61% and 71%, respectively. Of the surviving patients, 75% have a disease-free and functioning bladder. All patients completed hypofractionated IMRT, and 19 patients tolerated all 4 cycles of chemotherapy. Acute grade 3 gastrointestinal or genitourinary toxicities occurred in only 4% of the patients, and acute grade 3 or 4 hematologic toxicities, liver toxicities, or both were experienced by 17% of the cohort. No patient experienced grade 4 gastrointestinal or genitourinary toxicity. Conclusions: Hypofractionated IMRT with concurrent radiosensitizing chemotherapy appears to be an effective and well-tolerated curative treatment strategy in the elderly population and should be considered for patients who are not candidates for cystectomy or who wish to avoid

  16. Treatment with intensity-modulated radiation therapy (IMRT) for breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Marta, G.N.; Hanna, S.A.; Gadia, R.

    2014-11-15

    Through the development of four relevant clinical questions related with the proposed subject, we tried to present the main evidence for safety, toxicity and effectiveness using different radiotherapy techniques. The study population consisted of female patients of all ages with primary breast cancer treated with radiation therapy to the whole breast, regardless of histological type, staging, context of treatment (radical, adjuvant or palliative) and whether comorbidities were present or not. For this, a systematic review of the literature was performed in primary scientific research databases (Medline - Pubmed; Embase - Elsevier; Lilacs - Bireme; Cochrane Library - Central Register of Controlled Trials). All articles available until July 22, 2013, were included. The search strategy used for Medline research is described in Appendix. Articles were selected based on critical evaluation in search of the best available evidence. Recommendations were prepared based on discussion with the writing group, composed of three members of the Brazilian Society of Radiotherapy. The guideline was reviewed by an independent group specializing in evidence-based clinical guidelines. After completion, the guideline was made available for public consultation for 15 days and the suggestions forwarded to the writers for evaluation and consideration into the final text. Objective: to assess the most appropriate method of radiation therapy for treating patients with primary breast tumors. (author)

  17. Volumetric modulated arc therapy is superior to conventional intensity modulated radiotherapy - a comparison among prostate cancer patients treated in an Australian centre

    Directory of Open Access Journals (Sweden)

    Haydu Lauren E

    2011-09-01

    Full Text Available Abstract Background Radiotherapy technology is expanding rapidly. Volumetric Modulated Arc Therapy (VMAT technologies such as RapidArc® (RA may be a more efficient way of delivering intensity-modulated radiotherapy-like (IM treatments. This study is an audit of the RA experience in an Australian department with a planning and economic comparison to IM. Methods 30 consecutive prostate cancer patients treated radically with RA were analyzed. Eight RA patients treated definitively were then completely re-planned with 3D conformal radiotherapy (3D; and a conventional sliding window IM technique; and a new RA plan. The acceptable plans and their treatment times were compared and analyzed for any significant difference. Differences in staff costs of treatment were computed and analyzed. Results Thirty patients had been treated to date with eight being treated definitely to at least 74 Gy, nine post high dose brachytherapy (HDR to 50.4Gy and 13 post prostatectomy to at least 64Gy. All radiotherapy courses were completed with no breaks. Acute rectal toxicity by the RTOG criteria was acceptable with 22 having no toxicity, seven with grade 1 and one had grade 2. Of the eight re-planned patients, none of the 3D (three-dimensional conformal radiotherapy plans were acceptable based on local guidelines for dose to organs at risk. There was no statistically significant difference in planning times between IM and RA (p = 0.792. IM had significantly greater MUs per fraction (1813.9 vs 590.2 p Conclusions 3D was incapable of covering a modern radiotherapy volume for the radical treatment of prostate cancer. These volumes can be treated via conventional IM and RA. RA was significantly more efficient, safe and cost effective than IM. VMAT technologies are a superior way of delivering IM-like treatments.

  18. Comparative dosimetry of volumetric modulated arc therapy and limited-angle static intensity-modulated radiation therapy for early-stage larynx cancer

    Energy Technology Data Exchange (ETDEWEB)

    Riegel, Adam C.; Antone, Jeffrey [Department of Radiation Medicine, North Shore–LIJ Health System, New Hyde, Park, NY (United States); Schwartz, David L., E-mail: dschwartz3@nshs.edu [Department of Radiation Medicine, North Shore–LIJ Health System, New Hyde, Park, NY (United States); Hofstra–NSLIJ School of Medicine, Hempstead, NY (United States)

    2013-04-01

    To compare relative carotid and normal tissue sparing using volumetric-modulated arc therapy (VMAT) or intensity-modulated radiation therapy (IMRT) for early-stage larynx cancer. Seven treatment plans were retrospectively created on 2 commercial treatment planning systems for 11 consecutive patients with T1-2N0 larynx cancer. Conventional plans consisted of opposed-wedged fields. IMRT planning used an anterior 3-field beam arrangement. Two VMAT plans were created, a full 360° arc and an anterior 180° arc. Given planning target volume (PTV) coverage of 95% total volume at 95% of 6300 cGy and maximum spinal cord dose below 2500 cGy, mean carotid artery dose was pushed as low as possible for each plan. Deliverability was assessed by comparing measured and planned planar dose with the gamma (γ) index. Full-arc planning provided the most effective carotid sparing but yielded the highest mean normal tissue dose (where normal tissue was defined as all soft tissue minus PTV). Static IMRT produced next-best carotid sparing with lower normal tissue dose. The anterior half-arc produced the highest carotid artery dose, in some cases comparable with conventional opposed fields. On the whole, carotid sparing was inversely related to normal tissue dose sparing. Mean γ indexes were much less than 1, consistent with accurate delivery of planned treatment. Full-arc VMAT yields greater carotid sparing than half-arc VMAT. Limited-angle IMRT remains a reasonable alternative to full-arc VMAT, given its ability to mediate the competing demands of carotid and normal tissue dose constraints. The respective clinical significance of carotid and normal tissue sparing will require prospective evaluation.

  19. SU-E-T-618: Plan Robustness Study of Volumetric-Modulated Arc Therapy Vs. Intensity-Modulated Radiation Therapy for Head and Neck Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W; Patel, S; Shen, J; Harrington, D; Stoker, J; Ding, X; Hu, Y; Wong, W; Halyard, M; Schild, S; Ezzell, G; Bues, M [Mayo Clinic Arizona, Phoenix, AZ (United States)

    2015-06-15

    Purpose: Lack of plan robustness may contribute to local failure in volumetric-modulated arc therapy (VMAT) to treat head and neck (H&N) cancer. Thus we compared plan robustness of VMAT with intensity-modulated radiation therapy (IMRT). Methods: VMAT and IMRT plans were created for 9 H&N cancer patients. For each plan, six new perturbed dose distributions were computed — one each for ± 3mm setup deviations along the S-I, A-P and L-R directions. We used three robustness quantification tools: (1) worst-case analysis (WCA); (2) dose-volume histograms (DVHs) band (DVHB); and (3) root-mean-square-dose deviation (RMSD) volume histogram (DDVH). DDVH represents the relative volume (y) on the vertical axis and the RMSD (x) on the horizontal axis. Similar to DVH, this means that y% of the volume of the indicated structure has the RMSD at least x Gy[RBE].The width from the first two methods at different target DVH indices (such as D95 and D5) and the area under the DDVH curves (AUC) for the target were used to indicate plan robustness. In these robustness quantification tools, the smaller the value, the more robust the plan is. Plan robustness evaluation metrics were compared using Wilcoxon test. Results: DVHB showed the width at D95 from IMRT to be larger than from VMAT (unit Gy) [1.59 vs 1.18 (p=0.49)], while the width at D5 from IMRT was found to be slightly larger than from VMAT [0.59 vs 0.54 (p=0.84)]. WCA showed similar results [D95: 3.28 vs 3.00 (p=0.56); D5: 1.68 vs 1.95 (p=0.23)]. DDVH showed the AUC from IMRT to be slightly smaller than from VMAT [1.13 vs 1.15 (p=0.43)]. Conclusion: VMAT plan robustness is comparable to IMRT plan robustness. The plan robustness conclusions from WCA and DVHB are DVH parameter dependent. On the other hand DDVH captures the overall effect of uncertainties on the dose to a volume of interest. NIH/NCI K25CA168984; Eagles Cancer Research Career Development; The Lawrence W. and Marilyn W. Matteson Fund for Cancer Research Mayo ASU Seed

  20. Multi-institutional comparison of volumetric modulated arc therapy vs. intensity-modulated radiation therapy for head-and-neck cancer : a planning study

    NARCIS (Netherlands)

    Holt, Andrea; Van Gestel, Dirk; Arends, Mark P.; Korevaar, Erik W.; Schuring, Danny; Kunze-Busch, Martina C.; Louwe, Rob J. W.; van Vliet-Vroegindeweij, Corine

    2013-01-01

    Background: Compared to static beam Intensity-Modulated Radiation Therapy (IMRT), the main advantage of Volumetric Modulated Arc Therapy (VMAT) is a shortened delivery time, which leads to improved patient comfort and possibly smaller intra-fraction movements. This study aims at a treatment planner-

  1. Multi-institutional comparison of volumetric modulated arc therapy vs. intensity-modulated radiation therapy for head-and-neck cancer: a planning study

    NARCIS (Netherlands)

    Holt, A.; Gestel, D. Van; Arends, M.P.; Korevaar, E.W.; Schuring, D.; Kunze-Busch, M.C.; Louwe, R.J.W.; Vliet-Vroegindeweij, C. van

    2013-01-01

    BACKGROUND: Compared to static beam Intensity-Modulated Radiation Therapy (IMRT), the main advantage of Volumetric Modulated Arc Therapy (VMAT) is a shortened delivery time, which leads to improved patient comfort and possibly smaller intra-fraction movements. This study aims at a treatment planner-

  2. Intensity modulated radiotherapy for high risk prostate cancer based on sentinel node SPECT imaging for target volume definition

    Directory of Open Access Journals (Sweden)

    Anastasiadis Aristotelis

    2005-07-01

    Full Text Available Abstract Background The RTOG 94-13 trial has provided evidence that patients with high risk prostate cancer benefit from an additional radiotherapy to the pelvic nodes combined with concomitant hormonal ablation. Since lymphatic drainage of the prostate is highly variable, the optimal target volume definition for the pelvic lymph nodes is problematic. To overcome this limitation, we tested the feasibility of an intensity modulated radiation therapy (IMRT protocol, taking under consideration the individual pelvic sentinel node drainage pattern by SPECT functional imaging. Methods Patients with high risk prostate cancer were included. Sentinel nodes (SN were localised 1.5–3 hours after injection of 250 MBq 99mTc-Nanocoll using a double-headed gamma camera with an integrated X-Ray device. All sentinel node localisations were included into the pelvic clinical target volume (CTV. Dose prescriptions were 50.4 Gy (5 × 1.8 Gy / week to the pelvis and 70.0 Gy (5 × 2.0 Gy / week to the prostate including the base of seminal vesicles or whole seminal vesicles. Patients were treated with IMRT. Furthermore a theoretical comparison between IMRT and a three-dimensional conformal technique was performed. Results Since 08/2003 6 patients were treated with this protocol. All patients had detectable sentinel lymph nodes (total 29. 4 of 6 patients showed sentinel node localisations (total 10, that would not have been treated adequately with CT-based planning ('geographical miss' only. The most common localisation for a probable geographical miss was the perirectal area. The comparison between dose-volume-histograms of IMRT- and conventional CT-planning demonstrated clear superiority of IMRT when all sentinel lymph nodes were included. IMRT allowed a significantly better sparing of normal tissue and reduced volumes of small bowel, large bowel and rectum irradiated with critical doses. No gastrointestinal or genitourinary acute toxicity Grade 3 or 4 (RTOG

  3. Clinical outcomes for gastric cancer following adjuvant chemoradiation utilizing intensity modulated versus three-dimensional conformal radiotherapy.

    Directory of Open Access Journals (Sweden)

    Gene-Fu F Liu

    Full Text Available PURPOSE/OBJECTIVES: To determine if intensity modulated radiation therapy (IMRT in the post-operative setting for gastric cancer was associated with reduced toxicity compared to 3D conformal radiation therapy (3DCRT. MATERIALS/METHODS: This retrospective study includes 24 patients with stage IB-IIIB gastric cancer consecutively treated from 2001-2010. All underwent surgery followed by adjuvant chemoradiation. Concurrent chemotherapy consisted of 5-FU/leucovorin (n = 21, epirubicin/cisplatin/5FU (n = 1, or none (n = 2. IMRT was utilized in 12 patients and 3DCRT in 12 patients. For both groups, the target volume included the tumor bed, anastomosis, gastric stump, and regional lymphatics. RESULTS: Median follow-up for the entire cohort was 19 months (range 0.4-8.5 years, and 49 months (0.5-8.5 years in surviving patients. The 3DCRT group received a median dose of 45 Gy, and the IMRT group received a median dose of 50.4 Gy (p = 0.0004. For the entire cohort, 3-year overall survival (OS was 40% and 3-year disease free survival (DFS was 41%. OS and DFS did not differ significantly between the groups. Acute toxicity was similar. Between 3DCRT and IMRT groups, during radiotherapy, median weight lost (3.2 vs. 3.3 kg, respectively; p = 0.47 and median percent weight loss were similar (5.0% vs. 4.3%, respectively; p = 0.43. Acute grade 2 toxicity was experienced by 8 patients receiving 3DCRT and 11 receiving IMRT (p = 0.32; acute grade 3 toxicity occurred in 1 patient receiving 3DCRT and none receiving IMRT (p = 1.0. No patients in either cohort experienced late grade 3 toxicity, including renal or gastrointestinal toxicity. At last follow up, the median increase in creatinine was 0.1 mg/dL in the IMRT group and 0.1 mg/dL in the 3DCRT group (p = 0.78. CONCLUSION: This study demonstrates that adjuvant chemoradiation for gastric cancer with IMRT to 50.4 Gy was well-tolerated and compared similarly in toxicity with 3DCRT to

  4. Intensity Modulated Radiation Therapy Dose Painting for Localized Prostate Cancer Using {sup 11}C-choline Positron Emission Tomography Scans

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Joe H. [Radiation Oncology Centre, Austin Health, Victoria (Australia); University of Melbourne, Victoria (Australia); Lim Joon, Daryl [Radiation Oncology Centre, Austin Health, Victoria (Australia); Lee, Sze Ting [University of Melbourne, Victoria (Australia); Centre for PET, Austin Health, Victoria (Australia); Ludwig Institute for Cancer Research, Victoria (Australia); Gong, Sylvia J. [Centre for PET, Austin Health, Victoria (Australia); Anderson, Nigel J. [Radiation Oncology Centre, Austin Health, Victoria (Australia); Scott, Andrew M. [University of Melbourne, Victoria (Australia); Centre for PET, Austin Health, Victoria (Australia); Ludwig Institute for Cancer Research, Victoria (Australia); Davis, Ian D. [University of Melbourne, Victoria (Australia); Ludwig Institute for Cancer Research, Victoria (Australia); Clouston, David [Focus Pathology, Victoria (Australia); Bolton, Damien [University of Melbourne, Victoria (Australia); Department of Urology, Austin Health, Victoria (Australia); Hamilton, Christopher S. [Radiation Oncology Centre, Austin Health, Victoria (Australia); Khoo, Vincent, E-mail: vincent.khoo@rmh.nhs.uk [Radiation Oncology Centre, Austin Health, Victoria (Australia); University of Melbourne, Victoria (Australia); Department of Clinical Oncology, Royal Marsden Hospital and Institute of Cancer Research, London (United Kingdom)

    2012-08-01

    Purpose: To demonstrate the technical feasibility of intensity modulated radiation therapy (IMRT) dose painting using {sup 11}C-choline positron emission tomography PET scans in patients with localized prostate cancer. Methods and Materials: This was an RT planning study of 8 patients with prostate cancer who had {sup 11}C-choline PET scans prior to radical prostatectomy. Two contours were semiautomatically generated on the basis of the PET scans for each patient: 60% and 70% of the maximum standardized uptake values (SUV{sub 60%} and SUV{sub 70%}). Three IMRT plans were generated for each patient: PLAN{sub 78}, which consisted of whole-prostate radiation therapy to 78 Gy; PLAN{sub 78-90}, which consisted of whole-prostate RT to 78 Gy, a boost to the SUV{sub 60%} to 84 Gy, and a further boost to the SUV{sub 70%} to 90 Gy; and PLAN{sub 72-90}, which consisted of whole-prostate RT to 72 Gy, a boost to the SUV{sub 60%} to 84 Gy, and a further boost to the SUV{sub 70%} to 90 Gy. The feasibility of these plans was judged by their ability to reach prescription doses while adhering to published dose constraints. Tumor control probabilities based on PET scan-defined volumes (TCP{sub PET}) and on prostatectomy-defined volumes (TCP{sub path}), and rectal normal tissue complication probabilities (NTCP) were compared between the plans. Results: All plans for all patients reached prescription doses while adhering to dose constraints. TCP{sub PET} values for PLAN{sub 78}, PLAN{sub 78-90}, and PLAN{sub 72-90} were 65%, 97%, and 96%, respectively. TCP{sub path} values were 71%, 97%, and 89%, respectively. Both PLAN{sub 78-90} and PLAN{sub 72-90} had significantly higher TCP{sub PET} (P=.002 and .001) and TCP{sub path} (P<.001 and .014) values than PLAN{sub 78}. PLAN{sub 78-90} and PLAN{sub 72-90} were not significantly different in terms of TCP{sub PET} or TCP{sub path}. There were no significant differences in rectal NTCPs between the 3 plans. Conclusions: IMRT dose painting for

  5. The effect of partially used high energy photon on intensity-modulated radiation therapy plan for head and neck cancer

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Nam Joon; Seok, Jin Yong; Won, Hui Su; Hong, Joo Wan; Choi, Ji Hun; Park, Jin Hong [Dept. of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of)

    2013-03-15

    A selection of proper energy in treatment planning is very important because of having different dose distribution in body as photon energy. In generally, the low energy photon has been used in intensity-modulated radiation therapy (IMRT) for head and neck (H and N) cancer. The aim of this study was to evaluate the effect of partially used high energy photon at posterior oblique fields on IMRT plan for H and N cancer. The study was carried out on 10 patients (nasopharyngeal cancer 5, tonsilar cancer 5) treated with IMRT in Seoul National University Bundang Hospital. CT images were acquired 3 mm of thickness in the same condition and the treatment plan was performed by Eclipse (Ver.7.1, Varian, Palo Alto, USA). Two plans were generated under same planing objectives, dose volume constraints, and eight fields setting: (1) The low energy plan (LEP) created using 6 MV beam alone, (2) the partially used high energy plan (PHEP) created partially using 15 MV beam at two posterior oblique fields with deeper penetration depths, while 6 MV beam was used at the rest of fields. The plans for LEP and PHEP were compared in terms of coverage, conformity index (CI) and homogeneity index (HI) for planning target volume (PTV). For organs at risk (OARs), D{sub mean} and D{sub 50%} were analyzed on both parotid glands and D{sub max}, D{sub 1%} for spinal cord were analyzed. Integral dose (ID) and total monitor unit (MU) were compared as addition parameters. For the comparing dose to normal tissue of posterior neck, the posterior-normal tissue volume (P-NTV) was set on the patients respectively. The D{sub mean}, V{sub 20Gy} and V{sub 25Gy} for P-NTV were evaluated by using dose volume histogram (DVH). The dose distributions were similar with regard to coverage, CI and HI for PTV between the LEP and PHEP. No evident difference was observed in the spinal cord. However, the D{sub mean}, D{sub 50%} for both parotid gland were slightly reduced by 0.6%, 0.7% in PHEP. The ID was reduced by 1

  6. Using a Reduced Spot Size for Intensity-Modulated Proton Therapy Potentially Improves Salivary Gland-Sparing in Oropharyngeal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Water, Tara A. van de, E-mail: t.a.van.de.water@rt.umcg.nl [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Lomax, Antony J. [Centre for Proton Therapy, Paul Scherrer Institute, Villigen-PSI (Switzerland); Bijl, Hendrik P.; Schilstra, Cornelis [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Hug, Eugen B. [Centre for Proton Therapy, Paul Scherrer Institute, Villigen-PSI (Switzerland); Langendijk, Johannes A. [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)

    2012-02-01

    Purpose: To investigate whether intensity-modulated proton therapy with a reduced spot size (rsIMPT) could further reduce the parotid and submandibular gland dose compared with previously calculated IMPT plans with a larger spot size. In addition, it was investigated whether the obtained dose reductions would theoretically translate into a reduction of normal tissue complication probabilities (NTCPs). Methods: Ten patients with N0 oropharyngeal cancer were included in a comparative treatment planning study. Both IMPT plans delivered simultaneously 70 Gy to the boost planning target volume (PTV) and 54 Gy to the elective nodal PTV. IMPT and rsIMPT used identical three-field beam arrangements. In the IMPT plans, the parotid and submandibular salivary glands were spared as much as possible. rsIMPT plans used identical dose-volume objectives for the parotid glands as those used by the IMPT plans, whereas the objectives for the submandibular glands were tightened further. NTCPs were calculated for salivary dysfunction and xerostomia. Results: Target coverage was similar for both IMPT techniques, whereas rsIMPT clearly improved target conformity. The mean doses in the parotid glands and submandibular glands were significantly lower for three-field rsIMPT (14.7 Gy and 46.9 Gy, respectively) than for three-field IMPT (16.8 Gy and 54.6 Gy, respectively). Hence, rsIMPT significantly reduced the NTCP of patient-rated xerostomia and parotid and contralateral submandibular salivary flow dysfunction (27%, 17%, and 43% respectively) compared with IMPT (39%, 20%, and 79%, respectively). In addition, mean dose values in the sublingual glands, the soft palate and oral cavity were also decreased. Obtained dose and NTCP reductions varied per patient. Conclusions: rsIMPT improved sparing of the salivary glands and reduced NTCP for xerostomia and parotid and submandibular salivary dysfunction, while maintaining similar target coverage results. It is expected that rsIMPT improves quality

  7. Assessment of Organ Motion in Postoperative Endometrial and Cervical Cancer Patients Treated With Intensity-Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Eleanor E.R., E-mail: Eleanor.harris@moffitt.org [Department of Radiation Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL (United States); Latifi, Kujtim; Rusthoven, Chad; Javedan, Ken; Forster, Kenneth [Department of Radiation Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL (United States)

    2011-11-15

    Purpose: Intensity-modulated radiation therapy (IMRT) may be useful to reduce toxicity in gynecologic cancer patients requiring postoperative pelvic irradiation. This study was undertaken to quantify vaginal wall organ motion during the course of postoperative pelvic irradiation using pelvic IMRT. Methods and Materials: Twenty-two consecutive patients treated with postoperative pelvic IMRT on helical tomotherapy had fiducial markers placed at the vaginal apex prior to simulation then daily megavoltage computed tomography (CT) scans for positioning. The daily positions of the fiducials were registered and measured in reference to the initial CT scan to quantify the degree of vaginal wall organ motion during the entire course of therapy. Results: The total motion of the fiducials center of mass (COM) was a median of 5.8 mm (range, 0.6-20.2 mm), and 95% of all COM positions fell within 15.7 mm of their original position. Directional margins of 3.1 mm along the right-left axis, 9.5 mm along the superoinferior axis, and of 12.1 mm along the anteroposterior axis encompassed the vaginal fiducials in 95% of treatments. Mean organ deformation for all patients was 3.9 mm, (range, 0-27.5 mm; standard deviation, 3.1 mm), with significant distortions of greater than 10 mm in 17% of secondary image sets. Conclusions: These data suggest a planning target volume margin of 16 mm will account for maximal organ motion in the majority of gynecologic patients undergoing postoperative pelvic IMRT, and it may be possible to incorporate directional motion into the planning target volume margin.

  8. Whole abdomen radiation therapy in ovarian cancers: a comparison between fixed beam and volumetric arc based intensity modulation

    Directory of Open Access Journals (Sweden)

    Clivio Alessandro

    2010-11-01

    Full Text Available Abstract Purpose A study was performed to assess dosimetric characteristics of volumetric modulated arcs (RapidArc, RA and fixed field intensity modulated therapy (IMRT for Whole Abdomen Radiotherapy (WAR after ovarian cancer. Methods and Materials Plans for IMRT and RA were optimised for 5 patients prescribing 25 Gy to the whole abdomen (PTV_WAR and 45 Gy to the pelvis and pelvic nodes (PTV_Pelvis with Simultaneous Integrated Boost (SIB technique. Plans were investigated for 6 MV (RA6, IMRT6 and 15 MV (RA15, IMRT15 photons. Objectives were: for both PTVs V90% > 95%, for PTV_Pelvis: Dmax Results IMRT and RapidArc resulted comparable for target coverage. For PTV_WAR, V90% was 99.8 ± 0.2% and 93.4 ± 7.3% for IMRT6 and IMRT15, and 98.4 ± 1.7 and 98.6 ± 0.9% for RA6 and RA15. Target coverage resulted improved for PTV_Pelvis. Dose homogeneity resulted slightly improved by RA (Uniformity was defined as U5-95% = D5%-D95%/Dmean. U5-95% for PTV_WAR was 0.34 ± 0.05 and 0.32 ± 0.06 (IMRT6 and IMRT15, 0.30 ± 0.03 and 0.26 ± 0.04 (RA6 and RA15; for PTV_Pelvis, it resulted equal to 0.1 for all techniques. For organs at risk, small differences were observed between the techniques. MU resulted 3130 ± 221 (IMRT6, 2841 ± 318 (IMRT15, 538 ± 29 (RA6, 635 ± 139 (RA15; the average measured treatment time was 18.0 ± 0.8 and 17.4 ± 2.2 minutes (IMRT6 and IMRT15 and 4.8 ± 0.2 (RA6 and RA15. GAIIMRT6 = 97.3 ± 2.6%, GAIIMRT15 = 94.4 ± 2.1%, GAIRA6 = 98.7 ± 1.0% and GAIRA15 = 95.7 ± 3.7%. Conclusion RapidArc showed to be a solution to WAR treatments offering good dosimetric features with significant logistic improvements compared to IMRT.

  9. Treatment and prognosis of patients with late rectal bleeding after intensity-modulated radiation therapy for prostate cancer

    Directory of Open Access Journals (Sweden)

    Takemoto Shinya

    2012-06-01

    Full Text Available Abstract Background Radiation proctitis after intensity-modulated radiation therapy (IMRT differs from that seen after pelvic irradiation in that this adverse event is a result of high-dose radiation to a very small area in the rectum. We evaluated the results of treatment for hemorrhagic proctitis after IMRT for prostate cancer. Methods Between November 2004 and February 2010, 403 patients with prostate cancer were treated with IMRT at 2 institutions. Among these patients, 64 patients who developed late rectal bleeding were evaluated. Forty patients had received IMRT using a linear accelerator and 24 by tomotherapy. Their median age was 72 years. Each patient was assessed clinically and/or endoscopically. Depending on the severity, steroid suppositories or enemas were administered up to twice daily and Argon plasma coagulation (APC was performed up to 3 times. Response to treatment was evaluated using the Rectal Bleeding Score (RBS, which is the sum of Frequency Score (graded from 1 to 3 by frequency of bleeding and Amount Score (graded from 1 to 3 by amount of bleeding. Stoppage of bleeding over 3 months was scored as RBS 1. Results The median follow-up period for treatment of rectal bleeding was 35 months (range, 12–69 months. Grade of bleeding was 1 in 31 patients, 2 in 26, and 3 in 7. Nineteen of 45 patients (42% observed without treatment showed improvement and bleeding stopped in 17 (38%, although mean RBS did not change significantly. Eighteen of 29 patients (62% treated with steroid suppositories or enemas showed improvement (mean RBS, from 4.1 ± 1.0 to 3.0 ± 1.8, p = 0.003 and bleeding stopped in 9 (31%. One patient treated with steroid enema 0.5-2 times a day for 12 months developed septic shock and died of multiple organ failure. All 12 patients treated with APC showed improvement (mean RBS, 4.7 ± 1.2 to 2.3 ± 1.4, p  Conclusions After adequate periods of observation, steroid suppositories

  10. Beam configuration selection for robust intensity-modulated proton therapy in cervical cancer using Pareto front comparison.

    Science.gov (United States)

    van de Schoot, A J A J; Visser, J; van Kesteren, Z; Janssen, T M; Rasch, C R N; Bel, A

    2016-02-21

    The Pareto front reflects the optimal trade-offs between conflicting objectives and can be used to quantify the effect of different beam configurations on plan robustness and dose-volume histogram parameters. Therefore, our aim was to develop and implement a method to automatically approach the Pareto front in robust intensity-modulated proton therapy (IMPT) planning. Additionally, clinically relevant Pareto fronts based on different beam configurations will be derived and compared to enable beam configuration selection in cervical cancer proton therapy. A method to iteratively approach the Pareto front by automatically generating robustly optimized IMPT plans was developed. To verify plan quality, IMPT plans were evaluated on robustness by simulating range and position errors and recalculating the dose. For five retrospectively selected cervical cancer patients, this method was applied for IMPT plans with three different beam configurations using two, three and four beams. 3D Pareto fronts were optimized on target coverage (CTV D(99%)) and OAR doses (rectum V30Gy; bladder V40Gy). Per patient, proportions of non-approved IMPT plans were determined and differences between patient-specific Pareto fronts were quantified in terms of CTV D(99%), rectum V(30Gy) and bladder V(40Gy) to perform beam configuration selection. Per patient and beam configuration, Pareto fronts were successfully sampled based on 200 IMPT plans of which on average 29% were non-approved plans. In all patients, IMPT plans based on the 2-beam set-up were completely dominated by plans with the 3-beam and 4-beam configuration. Compared to the 3-beam set-up, the 4-beam set-up increased the median CTV D(99%) on average by 0.2 Gy and decreased the median rectum V(30Gy) and median bladder V(40Gy) on average by 3.6% and 1.3%, respectively. This study demonstrates a method to automatically derive Pareto fronts in robust IMPT planning. For all patients, the defined four-beam configuration was found optimal

  11. Role of Principal Component Analysis in Predicting Toxicity in Prostate Cancer Patients Treated With Hypofractionated Intensity-Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Vesprini, Danny [Department of Radiation Oncology, Sunnybrook Odette Cancer Center, Toronto, Ontario (Canada); Radiation Medicine Program, Princess Margaret Hospital, University Health Network, and Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Sia, Michael [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, and Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Lockwood, Gina [Department of Clinical Study Co-ordination and Biostatistics, Princess Margaret Hospital, University Health Network, Toronto, Ontario (Canada); Moseley, Douglas; Rosewall, Tara; Bayley, Andrew; Bristow, Robert; Chung, Peter; Menard, Cynthia; Milosevic, Michael; Warde, Padraig [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, and Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Catton, Charles, E-mail: charles.catton@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, and Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada)

    2011-11-15

    Purpose: To determine if principal component analysis (PCA) and standard parameters of rectal and bladder wall dose-volume histograms (DVHs) of prostate cancer patients treated with hypofractionated image-guided intensity-modulated radiotherapy (hypo-IMRT) can predict acute and late gastrointestinal (GI) toxicity. Methods and Materials: One hundred twenty-one patients underwent hypo-IMRT at 3 Gy/fraction, 5 days/week to either 60 Gy or 66 Gy, with daily online image guidance. Acute and late GI and genitourinary (GU) toxicity were recorded weekly during treatment and at each follow-up. All Radiation Therapy Oncology Group (RTOG) criteria toxicity scores were dichotomized as <2 and {>=}2. Standard dosimetric parameters and the first five to six principal components (PCs) of bladder and rectal wall DVHs were tested for association with the dichotomized toxicity outcomes, using logistic regression. Results: Median follow-up of all patients was 47 months (60 Gy cohort= 52 months; 66 Gy cohort= 31 months). The incidence rates of {>=}2 acute GI and GU toxicity were 14% and 29%, respectively, with no Grade {>=}3 acute GU toxicity. Late GI and GU toxicity scores {>=}2 were 16% and 15%, respectively. There was a significant difference in late GI toxicity {>=}2 when comparing the 66 Gy to the 60 Gy cohort (38% vs. 8%, respectively, p = 0.0003). The first PC of the rectal DVH was associated with late GI toxicity (odds ratio [OR], 6.91; p < 0.001), though it was not significantly stronger than standard DVH parameters such as Dmax (OR, 6.9; p < 0.001) or percentage of the organ receiving a 50% dose (V50) (OR, 5.95; p = 0 .001). Conclusions: Hypofractionated treatment with 60 Gy in 3 Gy fractions is well tolerated. There is a steep dose response curve between 60 Gy and 66 Gy for RTOG Grade {>=}2 GI effects with the dose constraints employed. Although PCA can predict late GI toxicity for patients treated with hypo-IMRT for prostate cancer, it provides no additional information

  12. Monte Carlo calculations support organ sparing in Deep-Inspiration Breath-Hold intensity-modulated radiotherapy for locally advanced lung cancer

    DEFF Research Database (Denmark)

    Ottosson, Wiviann; Sibolt, Patrik; Larsen, Christina

    2015-01-01

    Background and purpose: Studies indicate that Deep-Inspiration Breath-Hold (DIBH) is advantageous over Free-Breathing (FB) for locally advanced lung cancer radiotherapy. However, these studies were based on simplified dose calculation algorithms, potentially critical due to the heterogeneous nature......) for intensity-modulated-radio therapy or volumetric-modulated-arc-therapy using 66 Gy in 33 fractions. All plans were re-calculated with MC. Results: Relative to FB, the total lung volume increased 86.8% in DIBH, while the gross tumor volume decreased 14.8%. MC revealed equally under- and over...

  13. SU-E-T-786: Utility of Gold Wires to Optimize Intensity Modulation Capacity of a Novel Directional Modulated Brachytherapy Tandem Applicator for Image Guided Cervical Cancer Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Han, D [University of California, San Diego, La Jolla, CA (United States); Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada); Safigholi, H; Soliman, A; Song, W [Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada); Scanderbeg, D [University of California, San Diego, La Jolla, CA (United States); UCSD Medical Center, La Jolla, CA (United States); Liu, Z [University of California, San Diego, La Jolla, CA (United States)

    2015-06-15

    Purpose: To evaluate the impact of using gold wires to differentially fill various channels on plan quality compared with conventional T&R applicator, inside a novel directional modulated brachytherapy (DMBT) tandem applicator for cervical cancer brachytherapy. Materials and Methods: The novel DMBT tandem applicator has a 5.4-mm diameter MR-compatible tungsten alloy enclosed in a 0.3-mm thick plastic tubing that wraps around the tandem. To modulate the radiation intensity, 6 symmetric peripheral holes of 1.3-mm diameter are grooved along the tungsten alloy rod. These grooved holes are differentially filled with gold wires to generate various degrees of directional beams. For example, three different fill patterns of 1) all void, 2) all filled except the hole containing the 192-Ir source, and 3) two adjacent holes to the 192-Ir source filled were Monte Carlo simulated. The resulting 3D dose distributions were imported into an in-house-coded inverse optimization planning system to generate HDR brachytherapy clinical plans for 19 patient cases. All plans generated were normalized to the same D90 as the clinical plans and D2cc doses of OARs were evaluated. Prescription ranged between 15 and 17.5Gy. Results: In general, the plans in case 1) resulted in the highest D2cc doses for the OARs with 11.65±2.30Gy, 7.47±3.05Gy, and 9.84±2.48Gy for bladder, rectum, and sigmoid, respectively, although the differences were small. For the case 2), D2cc doses were 11.61±2.29Gy, 7.41±3.07Gy, and 9.75±2.45Gy, respectively. And, for the case 3), D2cc doses were 11.60±2.28Gy, 7.41±3.05Gy, and 9.74±2.45Gy, respectively. Difference between 1) and 2) cases were small with the average D2cc difference of <0.64%. Difference between 1) and 3) cases were even smaller with the average D2cc difference of <0.1%. Conclusions: There is a minimal clinical benefit by differentially filling grooved holes in the novel DMBT tandem applicator for image guided cervical cancer brachytherapy.

  14. Radiobiologic comparison of helical tomotherapy, intensity modulated radiotherapy, and conformal radiotherapy in treating lung cancer accounting for secondary malignancy risks

    Energy Technology Data Exchange (ETDEWEB)

    Komisopoulos, Georgios [Department of Medical Physics, Medical School, University of Patras, Patras (Greece); Mavroidis, Panayiotis, E-mail: mavroidis@uthscsa.edu [Department of Radiation Oncology, University of Texas Health Sciences Center at San Antonio, San Antonio, TX (United States); Department of Medical Radiation Physics, Karolinska Institutet and Stockholm University, Stockholm (Sweden); Rodriguez, Salvador; Stathakis, Sotirios; Papanikolaou, Nikos [Department of Radiation Oncology, University of Texas Health Sciences Center at San Antonio, San Antonio, TX (United States); Nikiforidis, Georgios C.; Sakellaropoulos, Georgios C. [Department of Medical Physics, Medical School, University of Patras, Patras (Greece)

    2014-01-01

    The aim of the present study is to examine the importance of using measures to predict the risk of inducing secondary malignancies in association with the clinical effectiveness of treatment plans in terms of tumor control and normal tissue complication probabilities. This is achieved by using radiobiologic parameters and measures, which may provide a closer association between clinical outcome and treatment delivery. Overall, 4 patients having been treated for lung cancer were examined. For each of them, 3 treatment plans were developed based on the helical tomotherapy (HT), multileaf collimator-based intensity modulated radiation therapy (IMRT), and 3-dimensional conformal radiation therapy (CRT) modalities. The different plans were evaluated using the complication-free tumor control probability (p{sub +}), the overall probability of injury (p{sub I}), the overall probability of control/benefit (p{sub B}), and the biologically effective uniform dose (D{sup ¯¯}). These radiobiologic measures were used to develop dose-response curves (p-D{sup ¯¯} diagram), which can help to evaluate different treatment plans when used in conjunction with standard dosimetric criteria. The risks for secondary malignancies in the heart and the contralateral lung were calculated for the 3 radiation modalities based on the corresponding dose-volume histograms (DVHs) of each patient. Regarding the overall evaluation of the different radiation modalities based on the p{sub +} index, the average values of the HT, IMRT, and CRT are 67.3%, 61.2%, and 68.2%, respectively. The corresponding average values of p{sub B} are 75.6%, 70.5%, and 71.0%, respectively, whereas the average values of p{sub I} are 8.3%, 9.3%, and 2.8%, respectively. Among the organs at risk (OARs), lungs show the highest probabilities for complications, which are 7.1%, 8.0%, and 1.3% for the HT, IMRT, and CRT modalities, respectively. Similarly, the biologically effective prescription doses (D{sub B}{sup ¯¯}) for the

  15. Dosimetric comparison between helical tomotherapy and intensity-modulated radiation therapy plans for non-small cell lung cancer

    Institute of Scientific and Technical Information of China (English)

    MENG Ling-ling; FENG Lin-chun; WANG Yun-lai; DAI Xiang-kun; XIE Chuan-bin

    2011-01-01

    Background Helical tomotherapy (HT) is a new image-guided intensity-modulated radiation therapy (IMRT) technique.It is reported that HT plan for non-small-cell lung cancer (NSCLC) can give better dose uniformity, dose gradients, and protection for the lung than IMRT plan. We compared the dosimetric characteristics of HT for NSCLC with those of conventional IMRT to observe the superiority of HT.Methods There was a comparative case series comprising 10 patients with NSCLC. Computed tomographic (CT) images of delineated targets were transferred to the PrecisePlan planning system (IMRT) and Tomo planning system (HT). The prescription doses were 70 Gy/33F for the gross tumor volume (GTV) and the visible lymph nodes (GTVnd),and 60 Gy/33F for the clinical target volume (CTV) and the clinical target volume of the visible lymph nodes (CTVnd). The dose restrictions for organs at risk were as follows: the maximum dose to spinal cord ≤45 Gy, V20 to the total lungs <30%,V50 to the heart <50%, and V55 to the esophagus <50%. Both plans were evaluated by means of the dose coverage of the targets, dose-volume histograms (DVHs), and other dosimetric indices.Results The dose coverage, conformity, and homogeneity of the targets' volumes were found to be satisfactory in both plans, but the homogeneity of the HT plan was better than that of IMRT. The high-dose radiation volume (V20-V30) to the lung and the mean lung dose (MLD) decreased (P<0.05), but the low-dose radiation volume (V5-V10) increased slightly in the HT plan (P>0.05). The maximum doses to the spinal cord, heart, esophagus and trachea in the HT plan were lower than those in the IMRT plan, but the differences were not statistically significant.Conclusions The HT plan provids better dose uniformity, dose gradients, and protectiqn for the organs at risk. It can reduce the high-dose radiation volume for lung and the MLD, but may deliver a larger lung volume of low-dose radiation.

  16. Treatment of left sided breast cancer for a patient with funnel chest: Volumetric-modulated arc therapy vs. 3D-CRT and intensity-modulated radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Haertl, Petra M., E-mail: petra.haertl@klinik.uni-regensburg.de [Department of Radiotherapy, Regensburg University Medical Center, Regensburg (Germany); Pohl, Fabian; Weidner, Karin; Groeger, Christian; Koelbl, Oliver; Dobler, Barbara [Department of Radiotherapy, Regensburg University Medical Center, Regensburg (Germany)

    2013-04-01

    This case study presents a rare case of left-sided breast cancer in a patient with funnel chest, which is a technical challenge for radiation therapy planning. To identify the best treatment technique for this case, 3 techniques were compared: conventional tangential fields (3D conformal radiotherapy [3D-CRT]), intensity-modulated radiotherapy (IMRT), and volumetric-modulated arc therapy (VMAT). The plans were created for a SynergyS® (Elekta, Ltd, Crawley, UK) linear accelerator with a BeamModulator™ head and 6-MV photons. The planning system was Oncentra Masterplan® v3.3 SP1 (Nucletron BV, Veenendal, Netherlands). Calculations were performed with collapsed cone algorithm. Dose prescription was 50.4 Gy to the average of the planning target volume (PTV). PTV coverage and homogeneity was comparable for all techniques. VMAT allowed reducing dose to the ipsilateral organs at risk (OAR) and the contralateral breast compared with IMRT and 3D-CRT: The volume of the left lung receiving 20 Gy was 19.3% for VMAT, 26.1% for IMRT, and 32.4% for 3D-CRT. In the heart, a D{sub 15%} of 9.7 Gy could be achieved with VMAT compared with 14 Gy for IMRT and 46 Gy for 3D-CRT. In the contralateral breast, D{sub 15%} was 6.4 Gy for VMAT, 8.8 Gy for IMRT, and 10.2 Gy for 3D-CRT. In the contralateral lung, however, the lowest dose was achieved with 3D-CRT with D{sub 10%} of 1.7 Gy for 3D-CRT, and 6.7 Gy for both IMRT and VMAT. The lowest number of monitor units (MU) per 1.8-Gy fraction was required by 3D-CRT (192 MU) followed by VMAT (518 MU) and IMRT (727 MU). Treatment time was similar for 3D-CRT (3 min) and VMAT (4 min) but substantially increased for IMRT (13 min). VMAT is considered the best treatment option for the presented case of a patient with funnel chest. It allows reducing dose in most OAR without compromising target coverage, keeping delivery time well below 5 minutes.

  17. Treatment of left sided breast cancer for a patient with funnel chest: volumetric-modulated arc therapy vs. 3D-CRT and intensity-modulated radiotherapy.

    Science.gov (United States)

    Haertl, Petra M; Pohl, Fabian; Weidner, Karin; Groeger, Christian; Koelbl, Oliver; Dobler, Barbara

    2013-01-01

    This case study presents a rare case of left-sided breast cancer in a patient with funnel chest, which is a technical challenge for radiation therapy planning. To identify the best treatment technique for this case, 3 techniques were compared: conventional tangential fields (3D conformal radiotherapy [3D-CRT]), intensity-modulated radiotherapy (IMRT), and volumetric-modulated arc therapy (VMAT). The plans were created for a SynergyS® (Elekta, Ltd, Crawley, UK) linear accelerator with a BeamModulator™ head and 6-MV photons. The planning system was Oncentra Masterplan® v3.3 SP1 (Nucletron BV, Veenendal, Netherlands). Calculations were performed with collapsed cone algorithm. Dose prescription was 50.4 Gy to the average of the planning target volume (PTV). PTV coverage and homogeneity was comparable for all techniques. VMAT allowed reducing dose to the ipsilateral organs at risk (OAR) and the contralateral breast compared with IMRT and 3D-CRT: The volume of the left lung receiving 20 Gy was 19.3% for VMAT, 26.1% for IMRT, and 32.4% for 3D-CRT. In the heart, a D(15%) of 9.7 Gy could be achieved with VMAT compared with 14 Gy for IMRT and 46 Gy for 3D-CRT. In the contralateral breast, D(15%) was 6.4 Gy for VMAT, 8.8 Gy for IMRT, and 10.2 Gy for 3D-CRT. In the contralateral lung, however, the lowest dose was achieved with 3D-CRT with D(10%) of 1.7 Gy for 3D-CRT, and 6.7 Gy for both IMRT and VMAT. The lowest number of monitor units (MU) per 1.8-Gy fraction was required by 3D-CRT (192 MU) followed by VMAT (518 MU) and IMRT (727 MU). Treatment time was similar for 3D-CRT (3 min) and VMAT (4 min) but substantially increased for IMRT (13 min). VMAT is considered the best treatment option for the presented case of a patient with funnel chest. It allows reducing dose in most OAR without compromising target coverage, keeping delivery time well below 5 minutes.

  18. Stereotactic body radiation therapy planning with duodenal sparing using volumetric-modulated arc therapy vs intensity-modulated radiation therapy in locally advanced pancreatic cancer: A dosimetric analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rachit; Wild, Aaron T.; Ziegler, Mark A.; Hooker, Ted K.; Dah, Samson D.; Tran, Phuoc T.; Kang, Jun; Smith, Koren; Zeng, Jing [Department of Radiation Oncology and Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Hospital, 401N. Broadway, Weinberg Suite 1440, Baltimore, MD 21231 (United States); Pawlik, Timothy M. [Department of Surgery, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Tryggestad, Erik [Department of Radiation Oncology and Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Hospital, 401N. Broadway, Weinberg Suite 1440, Baltimore, MD 21231 (United States); Ford, Eric [Department of Radiation Oncology, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA (United States); Herman, Joseph M., E-mail: jherma15@jhmi.edu [Department of Radiation Oncology and Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Hospital, 401N. Broadway, Weinberg Suite 1440, Baltimore, MD 21231 (United States)

    2013-10-01

    Stereotactic body radiation therapy (SBRT) achieves excellent local control for locally advanced pancreatic cancer (LAPC), but may increase late duodenal toxicity. Volumetric-modulated arc therapy (VMAT) delivers intensity-modulated radiation therapy (IMRT) with a rotating gantry rather than multiple fixed beams. This study dosimetrically evaluates the feasibility of implementing duodenal constraints for SBRT using VMAT vs IMRT. Non–duodenal sparing (NS) and duodenal-sparing (DS) VMAT and IMRT plans delivering 25 Gy in 1 fraction were generated for 15 patients with LAPC. DS plans were constrained to duodenal D{sub max} of<30 Gy at any point. VMAT used 1 360° coplanar arc with 4° spacing between control points, whereas IMRT used 9 coplanar beams with fixed gantry positions at 40° angles. Dosimetric parameters for target volumes and organs at risk were compared for DS planning vs NS planning and VMAT vs IMRT using paired-sample Wilcoxon signed rank tests. Both DS VMAT and DS IMRT achieved significantly reduced duodenal D{sub mean}, D{sub max}, D{sub 1cc}, D{sub 4%}, and V{sub 20} {sub Gy} compared with NS plans (all p≤0.002). DS constraints compromised target coverage for IMRT as demonstrated by reduced V{sub 95%} (p = 0.01) and D{sub mean} (p = 0.02), but not for VMAT. DS constraints resulted in increased dose to right kidney, spinal cord, stomach, and liver for VMAT. Direct comparison of DS VMAT and DS IMRT revealed that VMAT was superior in sparing the left kidney (p<0.001) and the spinal cord (p<0.001), whereas IMRT was superior in sparing the stomach (p = 0.05) and the liver (p = 0.003). DS VMAT required 21% fewer monitor units (p<0.001) and delivered treatment 2.4 minutes faster (p<0.001) than DS IMRT. Implementing DS constraints during SBRT planning for LAPC can significantly reduce duodenal point or volumetric dose parameters for both VMAT and IMRT. The primary consequence of implementing DS constraints for VMAT is increased dose to other organs at

  19. Image-guided intensity-modulated radiotherapy of prostate cancer. Analysis of interfractional errors and acute toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Rudat, Volker; Nour, A.; Hammoud, M.; Alaradi, A.; Mohammed, A. [Saad Specialist Hospital, Department of Radiation Oncology, Al Khobar (Saudi Arabia)

    2016-02-15

    The aim of the study was to estimate interfractional deviations in patient and prostate position, the impact of the frequency of online verification on the treatment margins, and to assess acute radiation reactions of high-dose external beam image-guided intensity-modulated radiotherapy (IG-IMRT) of localized prostate cancer. IG-IMRT was performed by daily online verification of implanted fiducial prostate markers using a megavoltage electronic portal imaging device (EPID). A total of 1011 image-guided treatment fractions from 23 consecutive unselected prostate cancer patients were analyzed. The median total dose was 79.2 Gy (range 77.4-81.0 Gy). Acute radiation reactions were assessed weekly during radiotherapy using the Common Terminology Criteria for Adverse Events (CTCAE) v.4.03. A relevant combined patient set-up and prostate motion population random error of 4-5 mm was observed. Compared to daily IGRT, image guidance every other day required an expansion of the CTV-PTV (clinical target volume-planning target volume) margin of 8.1, 6.6, and 4.1 mm in the longitudinal, vertical, and lateral directions, thereby, increasing the PTV by approximately 30-40 %. No grade 3 or 4 acute radiation reactions were observed with daily IG-IMRT. A high dose with surprisingly low acute toxicity can be applied with daily IG-IMRT using implanted fiducial prostate markers. Daily image guidance is clearly superior to image guidance every other fraction concerning adequate target coverage with minimal margins. (orig.) [German] Ziel der Studie war es, die interfraktionelle Variabilitaet der Patientenlagerung und Prostataposition, den Einfluss der Bildgebungsfrequenz und die akuten Strahlenreaktionen bei einer hochdosierten bildgesteuerten intensitaetsmodulierten Strahlentherapie (IG-IMRT) des Prostatakarzinoms zu untersuchen. IG-IMRT wurde durch taegliche Verifikation von implantierten roentgendichten Prostatamarkern mittels Megavolt-Bildgebung (''electronic portal imaging

  20. Intensity-Modulated Radiotherapy in the Treatment of Oropharyngeal Cancer: An Update of the Memorial Sloan-Kettering Cancer Center Experience

    Energy Technology Data Exchange (ETDEWEB)

    Setton, Jeremy; Caria, Nicola; Romanyshyn, Jonathan; Koutcher, Lawrence; Wolden, Suzanne L.; Zelefsky, Michael J.; Rowan, Nicholas [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Sherman, Eric J.; Fury, Matthew G.; Pfister, David G. [Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Wong, Richard J.; Shah, Jatin P.; Kraus, Dennis H. [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Shi Weiji; Zhang Zhigang [Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Schupak, Karen D.; Gelblum, Daphna Y.; Rao, Shyam D. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Lee, Nancy Y., E-mail: Leen2@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    2012-01-01

    Purpose: To update the Memorial Sloan-Kettering Cancer Center's experience with intensity-modulated radiotherapy (IMRT) in the treatment of oropharyngeal cancer (OPC). Methods and Materials: Between September 1998 and April 2009, 442 patients with histologically confirmed OPC underwent IMRT at our center. There were 379 men and 63 women with a median age of 57 years (range, 27-91). The disease was Stage I in 2%, Stage II in 4%, Stage III in 21%, and Stage IV in 73% of patients. The primary tumor subsite was tonsil in 50%, base of tongue in 46%, pharyngeal wall in 3%, and soft palate in 2%. The median prescription dose to the planning target volume of the gross tumor was 70 Gy for definitive (n = 412) cases and 66 Gy for postoperative cases (n = 30). A total 404 patients (91%) received chemotherapy, including 389 (88%) who received concurrent chemotherapy, the majority of which was platinum-based. Results: Median follow-up among surviving patients was 36.8 months (range, 3-135). The 3-year cumulative incidence of local failure, regional failure, and distant metastasis was 5.4%, 5.6%, and 12.5%, respectively. The 3-year OS rate was 84.9%. The incidence of late dysphagia and late xerostomia {>=}Grade 2 was 11% and 29%, respectively. Conclusions: Our results confirm the feasibility of IMRT in achieving excellent locoregional control and low rates of xerostomia. According to our knowledge, this study is the largest report of patients treated with IMRT for OPC.

  1. Intensity-modulated radiotherapy for laryngeal and hypopharyngeal cancer. Minimization of late dysphagia without jeopardizing tumor control

    Energy Technology Data Exchange (ETDEWEB)

    Modesto, Anouchka; Laprie, Anne; Graff, Pierre; Rives, Michel [Institut Universitaire du Cancer, Department of Radiation Oncology, Institut Claudius Regaud, Toulouse (France); Vieillevigne, Laure [Institut Universitaire du Cancer, Department of Medical Physics, Toulouse (France); Sarini, Jerome; Vergez, Sebastien; Farenc, Jean-Claude [Institut Universitaire du Cancer, Department of Head and Neck Surgery, Toulouse (France); Delord, Jean-Pierre [Institut Universitaire du Cancer, Department of Medical Oncology, Toulouse (France); Vigarios, Emmanuelle [Centre Hospitalo Universitaire de Rangueil, Dental Surgery Department, Toulouse (France); Filleron, Thomas [Institut Universitaire du Cancer, Department of Biostatistics, Toulouse (France)

    2014-11-01

    The purpose of this work was to retrospectively determine the value of intensity-modulated radiotherapy (IMRT) in patients with laryngeal and hypopharyngeal squamous cell carcinoma (LHSCC), on outcome and treatment-related toxicity compared to 3-dimensional conformal radiotherapy (3D-CRT). A total of 175 consecutive patients were treated between 2007 and 2012 at our institution with curative intent RT and were included in this study: 90 were treated with 3D-CRT and 85 with IMRT. Oncologic outcomes were estimated using Kaplan-Meier statistics; acute and late toxicities were scored according to the Common Toxicity Criteria for Adverse Events scale v 3.0. Median follow-up was 35 months (range 32-42 months; 95% confidence interval 95 %). Two-year disease-free survival did not vary, regardless of the technique used (69 % for 3D-CRT vs. 72 %; for IMRT, p = 0.16). Variables evaluated as severe late toxicities were all statistically lower with IMRT compared with 3D-CRT: xerostomia (0 vs. 12 %; p < 0.0001), dysphagia (4 vs. 26 %; p < 0.0001), and feeding-tube dependency (1 vs 13 %; p = 0.0044). The rates of overall grade ≥ 3 late toxicities for the IMRT and 3D-CRT groups were 4.1 vs. 41.4 %, respectively (p < 0.0001). IMRT for laryngeal and hypopharyngeal cancer minimizes late dysphagia without jeopardizing tumor control and outcome. (orig.) [German] Das Ziel dieser Studie war es, retrospektiv den Nutzen der intensitaetsmodulierten Strahlentherapie (IMRT) in der Behandlung von Patienten mit Plattenepithelkarzinom von Kehlkopf und Hypopharynx (LHSCC) zu bewerten und mit dem Outcome und den Spaetfolgen der 3-D-konformalen Strahlentherapie (3D-CRT) zu vergleichen. Insgesamt wurden zwischen Januar 2007 und Dezember 2012175 LHSCC-Patienten mit einer RT behandelt und in die Studie aufgenommen: 85 Patienten wurden mit 3D-CRT und 90 Patienten mit IMRT behandelt.Das onkologische Outcome wurde mittels Kaplan-Meier-Statistik ermittelt und Akut- und Spaettoxizitaeten anhand der CTCAE

  2. Five-year Results of Whole Breast Intensity Modulated Radiation Therapy for the Treatment of Early Stage Breast Cancer: The Fox Chase Cancer Center Experience

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Lanea M.M., E-mail: Lanea.Keller@fccc.edu [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Sopka, Dennis M. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Li Tianyu [Department of Biostatistics, Fox Chase Cancer Center, Philadelphia, PA (United States); Klayton, Tracy; Li Jinsheng; Anderson, Penny R. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Bleicher, Richard J.; Sigurdson, Elin R. [Department of Surgical Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Freedman, Gary M. [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States)

    2012-11-15

    Purpose: To report the 5-year outcomes using whole-breast intensity-modulated radiation therapy (IMRT) for the treatment of early-stage-breast cancer at the Fox Chase Cancer Center. Methods and Materials: A total of 946 women with early-stage breast cancer (stage 0, I, or II) were treated with IMRT after surgery with or without systemic therapy from 2003-2010. Whole-breast radiation was delivered via an IMRT technique with a median whole-breast radiation dose of 46 Gy and median tumor bed boost of 14 Gy. Endpoints included local-regional recurrence, cosmesis, and late complications. Results: With a median follow-up of 31 months (range, 1-97 months), there were 12 ipsilateral breast tumor recurrences (IBTR) and one locoregional recurrence. The 5-year actuarial IBTR and locoregional recurrence rates were 2.0% and 2.4%. Physician-reported cosmestic outcomes were available for 645 patients: 63% were considered 'excellent', 33% 'good', and <1.5% 'fair/poor'. For physician-reported cosmesis, boost doses {>=}16 Gy, breast size >900 cc, or boost volumes >34 cc were significantly associated with a 'fair/poor' cosmetic outcome. Fibrosis, edema, erythema, and telangectasia were also associated with 'fair/poor' physician-reported cosmesis; erythema and telangectasia remained significant on multivariate analysis. Patient-reported cosmesis was available for 548 patients, and 33%, 50%, and 17% of patients reported 'excellent', 'good', and 'fair/poor' cosmesis, respectively. The use of a boost and increased boost volume: breast volume ratio were significantly associated with 'fair/poor' outcomes. No parameter for patient-reported cosmesis was significant on multivariate analysis. The chances of experiencing a treatment related effect was significantly associated with a boost dose {>=}16 Gy, receipt of chemotherapy and endocrine therapy, large breast size, and electron boost energy

  3. Importance of contouring the cervical spine levels in initial intensity-modulated radiation therapy radiation for head and neck cancers: Implications for re-irradiation

    Directory of Open Access Journals (Sweden)

    Parashar Bhupesh

    2009-01-01

    Full Text Available Aim: To evaluate the maximum differential cervical spinal (C-spine cord dose in intensity-modulated radiation therapy (IMRT plans of patients undergoing radiotherapy for treatment of head and neck cancer. Materials and Methods: The C-spine of ten head and neck cancer patients that were planned using IMRT and each cervical vertebral body and the right and left sides was contoured by splitting the cord in the center. Dose-volume histograms (DVH and maximum point doses were obtained for each contour and compared. Results: The dose to the cord varied with the location of the primary tumor but such variation was not consistently seen. This report provides information that is critical for planning reirradiation treatments. We recommend that contouring of the C-spine cord with IMRT should include outlining of each cervical cord level and identification of the right and the left sides of the cord on each plan.

  4. Comparison of the dose distribution obtained from dosimetric systems with intensity modulated radiotherapy planning system in the treatment of prostate cancer

    Science.gov (United States)

    Gökçe, M.; Uslu, D. Koçyiǧit; Ertunç, C.; Karalı, T.

    2016-03-01

    The aim of this study is to compare Intensity Modulated Radiation Therapy (IMRT) plan of prostate cancer patients with different dose verification systems in dosimetric aspects and to compare these systems with each other in terms of reliability, applicability and application time. Dosimetric control processes of IMRT plan of three prostate cancer patients were carried out using thermoluminescent dosimeter (TLD), ion chamber (IC) and 2D Array detector systems. The difference between the dose values obtained from the dosimetric systems and treatment planning system (TPS) were found to be about % 5. For the measured (TLD) and calculated (TPS) doses %3 percentage differences were obtained for the points close to center while percentage differences increased at the field edges. It was found that TLD and IC measurements will increase the precision and reliability of the results of 2D Array.

  5. Intensity Modulated Accelerated Partial Breast Irradiation Before Surgery in Treating Older Patients With Hormone Responsive Stage 0-I Breast Cancer

    Science.gov (United States)

    2016-05-04

    Ductal Breast Carcinoma in Situ; Estrogen Receptor-negative Breast Cancer; Estrogen Receptor-positive Breast Cancer; Invasive Ductal Breast Carcinoma; Invasive Ductal Breast Carcinoma With Predominant Intraductal Component; Lobular Breast Carcinoma in Situ; Medullary Ductal Breast Carcinoma With Lymphocytic Infiltrate; Mucinous Ductal Breast Carcinoma; Papillary Ductal Breast Carcinoma; Progesterone Receptor-positive Breast Cancer; Stage IA Breast Cancer; Stage IB Breast Cancer; Tubular Ductal Breast Carcinoma

  6. Comparison of Heart and Coronary Artery Doses Associated With Intensity-Modulated Radiotherapy Versus Three-Dimensional Conformal Radiotherapy for Distal Esophageal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kole, Thomas P.; Aghayere, Osarhieme; Kwah, Jason [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Yorke, Ellen D. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Goodman, Karyn A., E-mail: goodmank@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    2012-08-01

    Purpose: To compare heart and coronary artery radiation exposure using intensity-modulated radiotherapy (IMRT) vs. four-field three-dimensional conformal radiotherapy (3D-CRT) treatment plans for patients with distal esophageal cancer undergoing chemoradiation. Methods and Materials: Nineteen patients with distal esophageal cancers treated with IMRT from March 2007 to May 2008 were identified. All patients were treated to 50.4 Gy with five-field IMRT plans. Theoretical 3D-CRT plans with four-field beam arrangements were generated. Dose-volume histograms of the planning target volume, heart, right coronary artery, left coronary artery, and other critical normal tissues were compared between the IMRT and 3D-CRT plans, and selected parameters were statistically evaluated using the Wilcoxon rank-sum test. Results: Intensity-modulated radiotherapy treatment planning showed significant reduction (p < 0.05) in heart dose over 3D-CRT as assessed by average mean dose (22.9 vs. 28.2 Gy) and V30 (24.8% vs. 61.0%). There was also significant sparing of the right coronary artery (average mean dose, 23.8 Gy vs. 35.5 Gy), whereas the left coronary artery showed no significant improvement (mean dose, 11.2 Gy vs. 9.2 Gy), p = 0.11. There was no significant difference in percentage of total lung volume receiving at least 10, 15, or 20 Gy or in the mean lung dose between the planning methods. There were also no significant differences observed for the kidneys, liver, stomach, or spinal cord. Intensity-modulated radiotherapy achieved a significant improvement in target conformity as measured by the conformality index (ratio of total volume receiving 95% of prescription dose to planning target volume receiving 95% of prescription dose), with the mean conformality index reduced from 1.56 to 1.30 using IMRT. Conclusions: Treatment of patients with distal esophageal cancer using IMRT significantly decreases the exposure of the heart and right coronary artery when compared with 3D

  7. Intensity-Modulated Radiotherapy with a Simultaneous Integrated Boost Combined with Chemotherapy in Stages III-IV Hypopharynx-Larynx Cancer: Treatment Compliance and Clinical Outcomes

    Directory of Open Access Journals (Sweden)

    Giovanni Franchin

    2014-01-01

    Full Text Available Objectives. Retrospective review of our experience using intensity-modulated radiotherapy with simultaneous integrated boost (SIB-IMRT combined with chemotherapy as the primary treatment of locoregionally advanced larynx and hypopharynx cancers. Materials and Methods. Between September 2008 and June 2012, 60 patients (26 with larynx and 34 hypopharynx cancers were treated. Our policy was to offer SIB-IMRT plus concurrent cisplatin to patients affected by larynx cancer stage T3N0-N1 and NCT with TPF (docetaxel/cisplatin/fluorouracil followed by SIB-IMRT to patients with larynx cancer stage T2-4N2-3 or hypopharynx cancer T2-4N0-3. SIB-IMRT consisted in a total dose of 70.95 Gy (2.15 Gy/fraction, 5 fractions/week to the gross primary and nodal disease and differentiated dosages for high risk and low risk nodal regions. Results. Complete remission was achieved in 53/60 (88% of patients. At a median follow up of 31 months (range 9–67, the rate of overall survival and locoregional control with functional larynx at 3 years were 68% and 60%, respectively. T stage (T1–3 versus T4 resulted in being significant for predicting 3-year freedom from relapse (it was 69% and 35%, resp., for T1–T3 and T4 tumors; P=0.04, while site of primary disease (larynx versus hypopharynx was not significant (P=0.35. Conclusion. Our results indicated that combining SIB-IMRT with induction chemotherapy or concurrent chemotherapy is an effective treatment strategy for organ preservation in advanced larynx/hypopharynx cancer.

  8. Exercise Intensity Modulation of Hepatic Lipid Metabolism

    Directory of Open Access Journals (Sweden)

    Fábio S. Lira

    2012-01-01

    Full Text Available Lipid metabolism in the liver is complex and involves the synthesis and secretion of very low density lipoproteins (VLDL, ketone bodies, and high rates of fatty acid oxidation, synthesis, and esterification. Exercise training induces several changes in lipid metabolism in the liver and affects VLDL secretion and fatty acid oxidation. These alterations are even more conspicuous in disease, as in obesity, and cancer cachexia. Our understanding of the mechanisms leading to metabolic adaptations in the liver as induced by exercise training has advanced considerably in the recent years, but much remains to be addressed. More recently, the adoption of high intensity exercise training has been put forward as a means of modulating hepatic metabolism. The purpose of the present paper is to summarise and discuss the merit of such new knowledge.

  9. Forward Intensity-Modulated Radiotherapy Planning in Breast Cancer to Improve Dose Homogeneity: Feasibility of Class Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Peulen, Heike, E-mail: h.peulen@nki.nl [Department of Radiation Oncology, MAASTRO Clinic, Maastricht (Netherlands); Hanbeukers, Bianca; Boersma, Liesbeth; Baardwijk, Angela van; Ende, Piet van den; Houben, Ruud; Jager, Jos; Murrer, Lars; Borger, Jacques [Department of Radiation Oncology, MAASTRO Clinic, Maastricht (Netherlands)

    2012-01-01

    Purpose: To explore forward planning methods for breast cancer treatment to obtain homogeneous dose distributions (using International Commission on Radiation Units and Measurements criteria) within normal tissue constraints and to determine the feasibility of class solutions. Methods and Materials: Treatment plans were optimized in a stepwise procedure for 60 patients referred for postlumpectomy irradiation using strict dose constraints: planning target volume (PTV){sub 95%} of >99%; V{sub 107%} of <1.8 cc; heart V{sub 5Gy} of <10% and V{sub 10Gy} of <5%; and mean lung dose of <7 Gy. Treatment planning started with classic tangential beams. Optimization was done by adding a maximum of four segments before adding beams, in a second step. A breath-hold technique was used for heart sparing if necessary. Results: Dose constraints were met for all 60 patients. The classic tangential beam setup was not sufficient for any of the patients; in one-third of patients, additional segments were required (<3), and in two-thirds of patients, additional beams (<2) were required. Logistic regression analyses revealed central breast diameter (CD) and central lung distance as independent predictors for transition from additional segments to additional beams, with a CD cut-off point at 23.6 cm. Conclusions: Treatment plans fulfilling strict dose homogeneity criteria and normal tissue constraints could be obtained for all patients by stepwise dose intensity modification using limited numbers of segments and additional beams. In patients with a CD of >23.6 cm, additional beams were always required.

  10. A comprehensive dosimetric study of pancreatic cancer treatment using three-dimensional conformal radiation therapy (3DCRT), intensity-modulated radiation therapy (IMRT), volumetric-modulated radiation therapy (VMAT), and passive-scattering and modulated-scanning proton therapy (PT)

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Xuanfeng; Dionisi, Francesco; Tang, Shikui; Ingram, Mark; Hung, Chun-Yu; Prionas, Evangelos; Lichtenwalner, Phil; Butterwick, Ian; Zhai, Huifang; Yin, Lingshu; Lin, Haibo; Kassaee, Alireza; Avery, Stephen, E-mail: stephen.avery@uphs.upenn.edu

    2014-07-01

    With traditional photon therapy to treat large postoperative pancreatic target volume, it often leads to poor tolerance of the therapy delivered and may contribute to interrupted treatment course. This study was performed to evaluate the potential advantage of using passive-scattering (PS) and modulated-scanning (MS) proton therapy (PT) to reduce normal tissue exposure in postoperative pancreatic cancer treatment. A total of 11 patients with postoperative pancreatic cancer who had been previously treated with PS PT in University of Pennsylvania Roberts Proton Therapy Center from 2010 to 2013 were identified. The clinical target volume (CTV) includes the pancreatic tumor bed as well as the adjacent high-risk nodal areas. Internal (iCTV) was generated from 4-dimensional (4D) computed tomography (CT), taking into account target motion from breathing cycle. Three-field and 4-field 3D conformal radiation therapy (3DCRT), 5-field intensity-modulated radiation therapy, 2-arc volumetric-modulated radiation therapy, and 2-field PS and MS PT were created on the patients’ average CT. All the plans delivered 50.4 Gy to the planning target volume (PTV). Overall, 98% of PTV was covered by 95% of the prescription dose and 99% of iCTV received 98% prescription dose. The results show that all the proton plans offer significant lower doses to the left kidney (mean and V{sub 18} {sub Gy}), stomach (mean and V{sub 20} {sub Gy}), and cord (maximum dose) compared with all the photon plans, except 3-field 3DCRT in cord maximum dose. In addition, MS PT also provides lower doses to the right kidney (mean and V{sub 18} {sub Gy}), liver (mean dose), total bowel (V{sub 20} {sub Gy} and mean dose), and small bowel (V{sub 15} {sub Gy} absolute volume ratio) compared with all the photon plans and PS PT. The dosimetric advantage of PT points to the possibility of treating tumor bed and comprehensive nodal areas while providing a more tolerable treatment course that could be used for dose

  11. Investigation of conformal and intensity-modulated radiation therapy techniques to determine the absorbed fetal dose in pregnant patients with breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Öğretici, Akın, E-mail: akinogretici@gmail.com; Akbaş, Uğur; Köksal, Canan; Bilge, Hatice

    2016-07-01

    The aim of this research was to investigate the fetal doses of pregnant patients undergoing conformal radiotherapy or intensity-modulated radiation therapy (IMRT) for breast cancers. An Alderson Rando phantom was chosen to simulate a pregnant patient with breast cancer who is receiving radiation therapy. This phantom was irradiated using the Varian Clinac DBX 600 system (Varian Medical System, Palo Alto, CA) linear accelerator, according to the standard treatment plans of both three-dimensional conformal radiation therapy (3-D CRT) and IMRT techniques. Thermoluminescent dosimeters were used to measure the irradiated phantom's virtually designated uterus area. Thermoluminescent dosimeter measurements (in the phantom) revealed that the mean cumulative fetal dose for 3-D CRT is 1.39 cGy and for IMRT it is 8.48 cGy, for a pregnant breast cancer woman who received radiation treatment of 50 Gy. The fetal dose was confirmed to increase by 70% for 3-D CRT and 40% for IMRT, if it is closer to the irradiated field by 5 cm. The mean fetal dose from 3-D CRT is 1.39 cGy and IMRT is 8.48 cGy, consistent with theoretic calculations. The IMRT technique causes the fetal dose to be 5 times more than that of 3-D CRT. Theoretic knowledge concerning the increase in the peripheral doses as the measurements approached the beam was also practically proven.

  12. Analysis of Intensity-Modulated Radiation Therapy (IMRT), Proton and 3D Conformal Radiotherapy (3D-CRT) for Reducing Perioperative Cardiopulmonary Complications in Esophageal Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Ted C.; Slater, Jerry M.; Nookala, Prashanth; Mifflin, Rachel; Grove, Roger; Ly, Anh M.; Patyal, Baldev; Slater, Jerry D.; Yang, Gary Y., E-mail: gyang@llu.edu [Department of Radiation Medicine, Loma Linda University Medical Center, 11234 Anderson Street, A875, Loma Linda, CA 92354 (United States)

    2014-12-05

    Background. While neoadjuvant concurrent chemoradiotherapy has improved outcomes for esophageal cancer patients, surgical complication rates remain high. The most frequent perioperative complications after trimodality therapy were cardiopulmonary in nature. The radiation modality utilized can be a strong mitigating factor of perioperative complications given the location of the esophagus and its proximity to the heart and lungs. The purpose of this study is to make a dosimetric comparison of Intensity-Modulated Radiation Therapy (IMRT), proton and 3D conformal radiotherapy (3D-CRT) with regard to reducing perioperative cardiopulmonary complications in esophageal cancer patients. Materials. Ten patients with esophageal cancer treated between 2010 and 2013 were evaluated in this study. All patients were simulated with contrast-enhanced CT imaging. Separate treatment plans using proton radiotherapy, IMRT, and 3D-CRT modalities were created for each patient. Dose-volume histograms were calculated and analyzed to compare plans between the three modalities. The organs at risk (OAR) being evaluated in this study are the heart, lungs, and spinal cord. To determine statistical significance, ANOVA and two-tailed paired t-tests were performed for all data parameters. Results. The proton plans showed decreased dose to various volumes of the heart and lungs in comparison to both the IMRT and 3D-CRT plans. There was no difference between the IMRT and 3D-CRT plans in dose delivered to the lung or heart. This finding was seen consistently across the parameters analyzed in this study. Conclusions. In patients receiving radiation therapy for esophageal cancer, proton plans are technically feasible while achieving adequate coverage with lower doses delivered to the lungs and cardiac structures. This may result in decreased cardiopulmonary toxicity and less morbidity to esophageal cancer patients.

  13. Plasma optical modulators for intense lasers

    CERN Document Server

    Yu, Lu-Le; Qian, Lie-Jia; Chen, Min; Weng, Su-Ming; Sheng, Zheng-Ming; Jaroszynski, D A; Mori, W B; Zhang, Jie

    2016-01-01

    Optical modulators can be made nowadays with high modulation speed, broad bandwidth, while being compact, owing to the recent advance in material science and microfabrication technology. However, these optical modulators usually work for low intensity light beams. Here, we present an ultrafast, plasma-based optical modulator, which can directly modulate high power lasers with intensity up to 10^16 W/cm^2 level to produce an extremely broad spectrum with a fractional bandwidth over 100%, extending to the mid-infrared regime in the low-frequency side. This concept relies on two co-propagating laser beams in a sub-mm-scale underdense plasma, where a drive laser pulse first excites an electron plasma wave in its wake while a following carrier laser beam is modulated by the plasma wave. The laser and plasma parameters suitable for the modulator to work are presented. Such optical modulators may enable new applications in the high field physics.

  14. Functional Image-Guided Radiotherapy Planning in Respiratory-Gated Intensity-Modulated Radiotherapy for Lung Cancer Patients With Chronic Obstructive Pulmonary Disease

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Tomoki, E-mail: tkkimura@hiroshima-u.ac.jp [Department of Radiation Oncology, Hiroshima University, Graduate School of Biomedical Sciences, Hiroshima City (Japan); Nishibuchi, Ikuno; Murakami, Yuji; Kenjo, Masahiro; Kaneyasu, Yuko; Nagata, Yasushi [Department of Radiation Oncology, Hiroshima University, Graduate School of Biomedical Sciences, Hiroshima City (Japan)

    2012-03-15

    Purpose: To investigate the incorporation of functional lung image-derived low attenuation area (LAA) based on four-dimensional computed tomography (4D-CT) into respiratory-gated intensity-modulated radiotherapy (IMRT) or volumetric modulated arc therapy (VMAT) in treatment planning for lung cancer patients with chronic obstructive pulmonary disease (COPD). Methods and Materials: Eight lung cancer patients with COPD were the subjects of this study. LAA was generated from 4D-CT data sets according to CT values of less than than -860 Hounsfield units (HU) as a threshold. The functional lung image was defined as the area where LAA was excluded from the image of the total lung. Two respiratory-gated radiotherapy plans (70 Gy/35 fractions) were designed and compared in each patient as follows: Plan A was an anatomical IMRT or VMAT plan based on the total lung; Plan F was a functional IMRT or VMAT plan based on the functional lung. Dosimetric parameters (percentage of total lung volume irradiated with {>=}20 Gy [V20], and mean dose of total lung [MLD]) of the two plans were compared. Results: V20 was lower in Plan F than in Plan A (mean 1.5%, p = 0.025 in IMRT, mean 1.6%, p = 0.044 in VMAT) achieved by a reduction in MLD (mean 0.23 Gy, p = 0.083 in IMRT, mean 0.5 Gy, p = 0.042 in VMAT). No differences were noted in target volume coverage and organ-at-risk doses. Conclusions: Functional IGRT planning based on LAA in respiratory-guided IMRT or VMAT appears to be effective in preserving a functional lung in lung cancer patients with COPD.

  15. Comparing morbidity and cancer control after 3D-conformal (70/74 Gy) and intensity modulated radiotherapy (78/82 Gy) for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Dolezel, Martin [Multiscan Alpha Pardubice Regional Hospital, Oncology Centre, Pardubice (Czech Republic); Charles University in Prague, First Faculty of Medicine, Prague (Czech Republic); Faculty of Medicine and Dentistry, Department of Oncology, Olomouc (Czech Republic); Odrazka, Karel [Multiscan Alpha Pardubice Regional Hospital, Oncology Centre, Pardubice (Czech Republic); Charles University in Prague, First Faculty of Medicine, Prague (Czech Republic); Charles University in Prague, Third Faculty of Medicine, Prague (Czech Republic); Zouhar, Milan; Jansa, Jan; Paluska, Petr [University Hospital Hradec Kralove, Department of Oncology and Radiotherapy, Hradec Kralove (Czech Republic); Vaculikova, Miloslava [Hospital Trutnov, Department of Oncology, Trutnov (Czech Republic); Sefrova, Jana [Hospital Prachatice, Department of Oncology, Prachatice (Czech Republic); Kohlova, Tereza [Proton Therapy Center, Prague (Czech Republic); Vanasek, Jaroslav [Multiscan Alpha Pardubice Regional Hospital, Oncology Centre, Pardubice (Czech Republic); Kovarik, Josef [The Freeman Hospital, Northern Centre for Cancer Care, Newcastle upon Tyne (United Kingdom)

    2015-04-01

    The purpose of this work was to compare toxicity and cancer control between patients with prostate cancer treated using three-dimensional conformal radiotherapy (3D-CRT) and those treated using intensity-modulated radiation therapy (IMRT). A total of 553 patients with prostate cancer were treated with 3D-CRT 70-74 Gy (3D-CRT 70, 3D-CRT 74) or IMRT 78-82 Gy (IMRT 78, IMRT/SIB 82). Late toxicity was scored according to FC-RTOG/LENT criteria. Biochemical failure was defined using the Phoenix and ASTRO definitions. The 5-year risk of grade 2-4 genitourinary toxicity was 26.3 % (3D-CRT 70), 27.2 % (3D-CRT 74), 17.3 % (IMRT 78), and 25.1 % (IMRT/SIB 82) without statistical differences. The 5-year risk of grade 2-4 gastrointestinal toxicity was 19.4 % (3D-CRT 70), 42.1 % (3D-CRT 74), 20.5 % (IMRT 78), and 26.6 % (IMRT/SIB 82). The differences between 3D-CRT 74 and 3D-CRT 70 and between 3D-CRT 74 and IMRT 78 were statistically significant (log rank p = 0.03). The 5-year Phoenix PSA relapse-free survival (PSA-RFS) in low-risk, intermediate-risk, and high-risk patients treated using 3D-CRT were 89.4, 65.5, and 57.8 %, respectively. Patients treated with IMRT achieved the following results: 90.9, 89.4, and 83.9 %. Clinical relapse-free survival (C-RFS) in patients treated using 3D-CRT vs. IMRT for the aforementioned groups were 94.7 vs. 100 %, 86.8 vs. 98.6 %, and 84.4 vs. 94.5 %. Disease-free survival (DFS) for patients treated using 3D-CRT were 83.1, 70.9, and 71.5 %. The IMRT group reached 95.8, 89.1, and 87.6 %. The PSA-RFS for intermediate- and high-risk patients were statistically significant, while C-RFS and DFS were marginally better. Dose escalation with IMRT was associated with improved cancer control in intermediate- and high-risk patients in comparison with 3D-CRT, without compromising toxicity. (orig.) [German] Es erfolgte ein Vergleich von Toxizitaet und Tumorkontrolle bei Patienten mit Prostatakarzinom nach der Behandlung mit dreidimensionaler konformaler

  16. Intensity-modulated radiation therapy for anal carcinoma; Radiotherapie conformationnelle avec modulation d'intensite des cancers de l'anus

    Energy Technology Data Exchange (ETDEWEB)

    Peiffert, D.; Moreau-Claeys, M.V.; Tournier-Rangeard, L.; Huger, S.; Marchesi, V. [Departement de radiotherapie, centre Alexis-Vautrin, 6, avenue de Bourgogne, 54511 Vandoeuvre-les-Nancy cedex (France)

    2011-10-15

    Anal canal carcinoma are highly curable by irradiation, combined with chemotherapy in locally advanced disease, with preservation of sphincter function. The clinical target volume for the nodes is extended, often including the inguinal nodes, which is not usual for other pelvic tumours. Acute and late effects are correlated with the volume and dose delivered to organs at risk, i. e. small bowel, bladder and increased by concomitant chemotherapy. Intensity modulated irradiation (IMRT) makes it possible to optimize the dose distribution in this 'complex U shaped' volume, while maintaining the dose distribution for the target volumes. The conversion from conformal irradiation to IMRT necessitates good knowledge of the definition and skills to delineate target volumes and organs at risk, including new volumes needed to optimize the dose distribution. Dosimetric and clinical benefits of IMRT are described, based on early descriptions and evidence-based publication. The growing development of IMRT in anal canal radiotherapy must be encouraged, and long-term benefits should be soon published. Radiation oncologists should precisely learn IMRT recommendations before starting the technique, and evaluate its early and late results for adverse effects, but also for long-term tumour control. (authors)

  17. Benefit of intensity modulated and image-guided radiotherapy in prostate cancer; Apports de la radiotherapie avec modulation d'intensite guidee par l'image dans les cancers prostatiques

    Energy Technology Data Exchange (ETDEWEB)

    Latorzeff, I.; Mazurier, J. [Service de radiotherapie, groupe Oncorad-Garonne, clinique Pasteur, -L' Atrium-, 31 - Toulouse (France); Boutry, C.; Dudouet, P. [Service d' oncologie, groupe Oncorad-Garonne, clinique du Pont-de-Chaume, 82 - Montauban (France); Richaud, P. [Departement de radiotherapie, institut Bergonie, 33 - Bordeaux (France); Crevoisier, R. de [Departement de radiotherapie, centre Eugene-Marquis, 35 - Rennes (France)

    2010-10-15

    External beam radiotherapy (RT) is used to treat all stages of localized prostate cancer. Using a 3D conformal RT (3DCRT) without any androgen deprivation, a clear dose-effect relationship has been shown in terms of both biochemical control and also unfortunately of rectal and urinary toxicity. Compared to a 'standard' 3DCRT, intensity modulated RT (IMRT) improves the dose distribution by mainly providing concave dose distribution and tight dose gradients. Based on large clinical experiences for at least one decade, IMRT is widely used to increase the dose in the prostate and therefore local control, without increasing toxicity. Indeed, toxicity rates observed after high dose delivered in the prostate (80 Gy) with IMRT appear no different than those observed after a standard dose (70 Gy) delivered by a standard 3DCRT. Arc IMRT appears a new promising IMRT modality, decreasing dramatically treatment duration. However, this IMRT-based dosimetric benefit may not be translated into a full clinical benefit, if intra-pelvic prostate motion is not taken in account. Image-guided radiotherapy (IGRT) should be therefore associated with IMRT for a maximal clinical benefit. This article is a literature review showing the interest of both combined approaches. (authors)

  18. Plasma optical modulators for intense lasers

    Science.gov (United States)

    Yu, Lu-Le; Zhao, Yao; Qian, Lie-Jia; Chen, Min; Weng, Su-Ming; Sheng, Zheng-Ming; Jaroszynski, D. A.; Mori, W. B.; Zhang, Jie

    2016-06-01

    Optical modulators can have high modulation speed and broad bandwidth, while being compact. However, these optical modulators usually work for low-intensity light beams. Here we present an ultrafast, plasma-based optical modulator, which can directly modulate high-power lasers with intensity up to 1016 W cm-2 to produce an extremely broad spectrum with a fractional bandwidth over 100%, extending to the mid-infrared regime in the low-frequency side. This concept relies on two co-propagating laser pulses in a sub-millimetre-scale underdense plasma, where a drive laser pulse first excites an electron plasma wave in its wake while a following carrier laser pulse is modulated by the plasma wave. The laser and plasma parameters suitable for the modulator to work are based on numerical simulations.

  19. A pilot study of intensity modulated radiation therapy with hypofractionated stereotactic body radiation therapy (SBRT) boost in the treatment of intermediate- to high-risk prostate cancer.

    Science.gov (United States)

    Oermann, Eric K; Slack, Rebecca S; Hanscom, Heather N; Lei, Sue; Suy, Simeng; Park, Hyeon U; Kim, Joy S; Sherer, Benjamin A; Collins, Brian T; Satinsky, Andrew N; Harter, K William; Batipps, Gerald P; Constantinople, Nicholas L; Dejter, Stephen W; Maxted, William C; Regan, James B; Pahira, John J; McGeagh, Kevin G; Jha, Reena C; Dawson, Nancy A; Dritschilo, Anatoly; Lynch, John H; Collins, Sean P

    2010-10-01

    Clinical data suggest that large radiation fractions are biologically superior to smaller fraction sizes in prostate cancer radiotherapy. The CyberKnife is an appealing delivery system for hypofractionated radiosurgery due to its ability to deliver highly conformal radiation and to track and adjust for prostate motion in real-time. We report our early experience using the CyberKnife to deliver a hypofractionated stereotactic body radiation therapy (SBRT) boost to patients with intermediate- to high-risk prostate cancer. Twenty-four patients were treated with hypofractionated SBRT and supplemental external radiation therapy plus or minus androgen deprivation therapy (ADT). Patients were treated with SBRT to a dose of 19.5 Gy in 3 fractions followed by intensity modulated radiation therapy (IMRT) to a dose of 50.4 Gy in 28 fractions. Quality of life data were collected with American Urological Association (AUA) symptom score and Expanded Prostate Cancer Index Composite (EPIC) questionnaires before and after treatment. PSA responses were monitored; acute urinary and rectal toxicities were assessed using Common Toxicity Criteria (CTC) v3. All 24 patients completed the planned treatment with an average follow-up of 9.3 months. For patients who did not receive ADT, the median pre-treatment PSA was 10.6 ng/ml and decreased in all patients to a median of 1.5 ng/ml by 6 months post-treatment. Acute effects associated with treatment included Grade 2 urinary and gastrointestinal toxicity but no patient experienced acute Grade 3 or greater toxicity. AUA and EPIC scores returned to baseline by six months post-treatment. Hypofractionated SBRT combined with IMRT offers radiobiological benefits of a large fraction boost for dose escalation and is a well tolerated treatment option for men with intermediate- to high-risk prostate cancer. Early results are encouraging with biochemical response and acceptable toxicity. These data provide a basis for the design of a phase II clinical

  20. A comparative analysis of 3D conformal deep inspiratory–breath hold and free-breathing intensity-modulated radiation therapy for left-sided breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Reardon, Kelli A.; Read, Paul W.; Morris, Monica M. [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States); Reardon, Michael A. [Department of Radiology, University of Virginia, Charlottesville, VA (United States); Geesey, Constance [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States); Wijesooriya, Krishni, E-mail: kw5wx@hscmail.mcc.virginia.edu [Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States)

    2013-07-01

    Patients undergoing radiation for left-sided breast cancer have increased rates of coronary artery disease. Free-breathing intensity-modulated radiation therapy (FB-IMRT) and 3-dimensional conformal deep inspiratory–breath hold (3D-DIBH) reduce cardiac irradiation. The purpose of this study is to compare the dose to organs at risk in FB-IMRT vs 3D-DIBH for patients with left-sided breast cancer. Ten patients with left-sided breast cancer had 2 computed tomography scans: free breathing and voluntary DIBH. Optimization of the IMRT plan was performed on the free-breathing scan using 6 noncoplanar tangential beams. The 3D-DIBH plan was optimized on the DIBH scan and used standard tangents. Mean volumes of the heart, the left anterior descending coronary artery (LAD), the total lung, and the right breast receiving 5% to 95% (5% increments) of the prescription dose were calculated. Mean volumes of the heart and the LAD were lower (p<0.05) in 3D-DIBH for volumes receiving 5% to 80% of the prescription dose for the heart and 5% for the LAD. Mean dose to the LAD and heart were lower in 3D-DIBH (p≤0.01). Mean volumes of the total lung were lower in FB-IMRT for dose levels 20% to 75% (p<0.05), but mean dose was not different. Mean volumes of the right breast were not different for any dose; however, mean dose was lower for 3D-DIBH (p = 0.04). 3D-DIBH is an alternative approach to FB-IMRT that provides a clinically equivalent treatment for patients with left-sided breast cancer while sparing organs at risk with increased ease of implementation.

  1. Prospective Randomized Phase 2 Trial of Intensity Modulated Radiation Therapy With or Without Oncolytic Adenovirus-Mediated Cytotoxic Gene Therapy in Intermediate-Risk Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Freytag, Svend O., E-mail: sfreyta1@hfhs.org [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Stricker, Hans [Vattikuti Urology Institute, Henry Ford Health System, Detroit, Michigan (United States); Lu, Mei [Public Health Sciences, Henry Ford Health System, Detroit, Michigan (United States); Elshaikh, Mohamed; Aref, Ibrahim; Pradhan, Deepak; Levin, Kenneth; Kim, Jae Ho [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Peabody, James [Vattikuti Urology Institute, Henry Ford Health System, Detroit, Michigan (United States); Siddiqui, Farzan; Barton, Kenneth; Pegg, Jan; Zhang, Yingshu; Cheng, Jingfang [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Oja-Tebbe, Nancy; Bourgeois, Renee [Public Health Sciences, Henry Ford Health System, Detroit, Michigan (United States); Gupta, Nilesh; Lane, Zhaoli [Pathology, Henry Ford Health System, Detroit, Michigan (United States); Rodriguez, Ron [Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); DeWeese, Theodore [Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); and others

    2014-06-01

    Purpose: To assess the safety and efficacy of combining oncolytic adenovirus-mediated cytotoxic gene therapy (OAMCGT) with intensity modulated radiation therapy (IMRT) in intermediate-risk prostate cancer. Methods and Materials: Forty-four men with intermediate-risk prostate cancer were randomly assigned to receive either OAMCGT plus IMRT (arm 1; n=21) or IMRT only (arm 2; n=23). The primary phase 2 endpoint was acute (≤90 days) toxicity. Secondary endpoints included quality of life (QOL), prostate biopsy (12-core) positivity at 2 years, freedom from biochemical/clinical failure (FFF), freedom from metastases, and survival. Results: Men in arm 1 exhibited a greater incidence of low-grade influenza-like symptoms, transaminitis, neutropenia, and thrombocytopenia than men in arm 2. There were no significant differences in gastrointestinal or genitourinary events or QOL between the 2 arms. Two-year prostate biopsies were obtained from 37 men (84%). Thirty-three percent of men in arm 1 were biopsy-positive versus 58% in arm 2, representing a 42% relative reduction in biopsy positivity in the investigational arm (P=.13). There was a 60% relative reduction in biopsy positivity in the investigational arm in men with <50% positive biopsy cores at baseline (P=.07). To date, 1 patient in each arm exhibited biochemical failure (arm 1, 4.8%; arm 2, 4.3%). No patient developed hormone-refractory or metastatic disease, and none has died from prostate cancer. Conclusions: Combining OAMCGT with IMRT does not exacerbate the most common side effects of prostate radiation therapy and suggests a clinically meaningful reduction in positive biopsy results at 2 years in men with intermediate-risk prostate cancer.

  2. Intensity Modulated Proton and Photon Therapy for Early Prostate Cancer With or Without Transperineal Injection of a Polyethylen Glycol Spacer: A Treatment Planning Comparison Study

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Damien C., E-mail: damien.weber@unige.ch [Department of Radiation Oncology, Geneva University Hospital, Geneva (Switzerland); Zilli, Thomas [Department of Radiation Oncology, Geneva University Hospital, Geneva (Switzerland); Vallee, Jean Paul [Department of Diagnostic Radiology, Geneva University Hospital, Geneva (Switzerland); Rouzaud, Michel; Miralbell, Raymond [Department of Radiation Oncology, Geneva University Hospital, Geneva (Switzerland); Cozzi, Luca [Oncology Institute of Southern Switzerland, Medical Physics Unit, Bellinzona (Switzerland)

    2012-11-01

    Purpose: Rectal toxicity is a serious adverse effect in early-stage prostate cancer patients treated with curative radiation therapy (RT). Injecting a spacer between Denonvilliers' fascia increases the distance between the prostate and the anterior rectal wall and may thus decrease the rectal radiation-induced toxicity. We assessed the dosimetric impact of this spacer with advanced delivery RT techniques, including intensity modulated RT (IMRT), volumetric modulated arc therapy (VMAT), and intensity modulated proton beam RT (IMPT). Methods and Materials: Eight prostate cancer patients were simulated for RT with or without spacer. Plans were computed for IMRT, VMAT, and IMPT using the Eclipse treatment planning system using both computed tomography spacer+ and spacer- data sets. Prostate {+-} seminal vesicle planning target volume [PTV] and organs at risk (OARs) dose-volume histograms were calculated. The results were analyzed using dose and volume metrics for comparative planning. Results: Regardless of the radiation technique, spacer injection decreased significantly the rectal dose in the 60- to 70-Gy range. Mean V{sub 70Gy} and V{sub 60Gy} with IMRT, VMAT, and IMPT planning were 5.3 {+-} 3.3%/13.9 {+-} 10.0%, 3.9 {+-} 3.2%/9.7 {+-} 5.7%, and 5.0 {+-} 3.5%/9.5 {+-} 4.7% after spacer injection. Before spacer administration, the corresponding values were 9.8 {+-} 5.4% (P=.012)/24.8 {+-} 7.8% (P=.012), 10.1 {+-} 3.0% (P=.002)/17.9 {+-} 3.9% (P=.003), and 9.7 {+-} 2.6% (P=.003)/14.7% {+-} 2.7% (P=.003). Importantly, spacer injection usually improved the PTV coverage for IMRT. With this technique, mean V{sub 70.2Gy} (P=.07) and V{sub 74.1Gy} (P=0.03) were 100 {+-} 0% to 99.8 {+-} 0.2% and 99.1 {+-} 1.2% to 95.8 {+-} 4.6% with and without Spacer, respectively. As a result of spacer injection, bladder doses were usually higher but not significantly so. Only IMPT managed to decrease the rectal dose after spacer injection for all dose levels, generally with no

  3. Predicting the severity and prognosis of trismus after intensity-modulated radiation therapy for oral cancer patients by magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Li-Chun Hsieh

    Full Text Available To develop magnetic resonance imaging (MRI indicators to predict trismus outcome for post-operative oral cavity cancer patients who received adjuvant intensity-modulated radiation therapy (IMRT, 22 patients with oral cancer treated with IMRT were studied over a two-year period. Signal abnormality scores (SA scores were computed from Likert-type ratings of the abnormalities of nine masticator structures and compared with the Mann-Whitney U-test and Kruskal-Wallis one-way ANOVA test between groups. Seventeen patients (77.3% experienced different degrees of trismus during the two-year follow-up period. The SA score correlated with the trismus grade (r = 0.52, p<0.005. Patients having progressive trismus had higher mean doses of radiation to multiple structures, including the masticator and lateral pterygoid muscles, and the parotid gland (p<0.05. In addition, this group also had higher SA-masticator muscle dose product at 6 months and SA scores at 12 months (p<0.05. At the optimum cut-off points of 0.38 for the propensity score, the sensitivity was 100% and the specificity was 93% for predicting the prognosis of the trismus patients. The SA score, as determined using MRI, can reflect the radiation injury and correlate to trismus severity. Together with the radiation dose, it could serve as a useful biomarker to predict the outcome and guide the management of trismus following radiation therapy.

  4. SU-E-P-58: Dosimetric Study of Conventional Intensity-Modulated Radiotherapy and Knowledge-Based Radiation Therapy for Postoperation of Cervix Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ma, C; Yin, Y [Shandong Tumor Hospital, Jinan, Shandong Provice (China)

    2015-06-15

    Purpose: To compare the dosimetric difference of the target volume and organs at risk(OARs) between conventional intensity-modulated radiotherapy(C-IMRT) and knowledge-based radiation therapy (KBRT) plans for cervix cancer. Methods: 39 patients with cervical cancer after surgery were randomly selected, 20 patient plans were used to create the model, the other 19 cases used for comparative evaluation. All plans were designed in Eclipse system. The prescription dose was 30.6Gy, 17 fractions, OARs dose satisfied to the clinical requirement. A paired t test was used to evaluate the differences of dose-volume histograms (DVH). Results: Comparaed to C-IMRT plan, the KBRT plan target can achieve the similar target dose coverage, D98,D95,D2,HI and CI had no difference (P≥0.05). The dose of rectum, bladder and femoral heads had no significant differences(P≥0.05). The time was used to design treatment plan was significant reduced. Conclusion: This study shows that postoperative radiotherapy of cervical KBRT plans can achieve the similar target and OARs dose, but the shorter designing time.

  5. Dosimetric evaluation of the skin-sparing effects of 3-dimensional conformal radiotherapy and intensity-modulated radiotherapy for left breast cancer.

    Science.gov (United States)

    Jo, In Young; Kim, Shin-Wook; Son, Seok Hyun

    2017-01-10

    The purpose of this study was to evaluate the skin-sparing effects of 3-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) in patients with early left-sided breast cancer. Twenty left breast cancer patients treated with whole breast radiotherapy following breast-conserving surgery were enrolled in this study, and the 3D-CRT and IMRT plans were generated for each patient. To evaluate the dose delivered to the skin, 2 mm thickness skin (2-mm skin) and 3 mm thickness skin (3-mm skin) were contoured and a dosimetric comparison between the 2 plans was performed. The target volume coverage was better in IMRT than in 3D-CRT. The mean dose was 50.8 Gy for 3D-CRT and 51.1 Gy for IMRT. V40Gy was 99.4% for 3D-CRT and 99.9% for IMRT. In the case of skin, the mean dose was higher in 3D-CRT than in IMRT (mean dose of 2-mm skin: 32.8 Gy and 24.2 Gy; mean dose of 3-mm skin: 37.2 Gy and 27.8 Gy, for 3D-CRT and IMRT, respectively). These results indicated that the skin-sparing effect is more prominent in IMRT compared to 3D-CRT without compromising the target volume coverage.

  6. Analysis and simulation of XPM intensity modulation

    Institute of Scientific and Technical Information of China (English)

    Jing Huang; Jianquan Yao

    2005-01-01

    Based on the split-step Fourier method and small signal analysis, an improved analytical solution which describes the cross-phase modulation (XPM) intensity is derived. It can suppress the spurious XPM intensity modulation efficiently in the whole transmission fiber. Thus it is more coincidence with the practical result. Furthermore, it is convenient, because it is independent of channel separation and the dispersion and nonlinear effects interact through the XPM intensity. A criterion of select the step size is described as the derived XPM intensity modulation being taken into account. It is non-uniform distribution method, the simulation accuracy is improved when the step size is determined by the improved XPM intensity.

  7. Changes in Pulmonary Function After Three-Dimensional Conformal Radiotherapy, Intensity-Modulated Radiotherapy, or Proton Beam Therapy for Non-Small-Cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Guerra, Jose L. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Radiation Oncology, Hospitales Universitarios Virgen del Rocio, Seville (Spain); Department of Medicine, Universitat Autonoma de Barcelona, Barcelona (Spain); Gomez, Daniel R., E-mail: dgomez@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Zhuang Yan; Levy, Lawrence B. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Eapen, George [Department of Pulmonary Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liu, Hongmei; Mohan, Radhe; Komaki, Ritsuko; Cox, James D.; Liao Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2012-07-15

    Purpose: To investigate the extent of change in pulmonary function over time after definitive radiotherapy for non-small-cell lung cancer (NSCLC) with modern techniques and to identify predictors of changes in pulmonary function according to patient, tumor, and treatment characteristics. Patients and Methods: We analyzed 250 patients who had received {>=}60 Gy radio(chemo)therapy for primary NSCLC in 1998-2010 and had undergone pulmonary function tests before and within 1 year after treatment. Ninety-three patients were treated with three-dimensional conformal radiotherapy, 97 with intensity-modulated radiotherapy, and 60 with proton beam therapy. Postradiation pulmonary function test values were evaluated among individual patients compared with the same patient's preradiation value at the following time intervals: 0-4 (T1), 5-8 (T2), and 9-12 (T3) months. Results: Lung diffusing capacity for carbon monoxide (DLCO) was reduced in the majority of patients along the three time periods after radiation, whereas the forced expiratory volume in 1 s per unit of vital capacity (FEV1/VC) showed an increase and decrease after radiation in a similar percentage of patients. There were baseline differences (stage, radiotherapy dose, concurrent chemotherapy) among the radiation technology groups. On multivariate analysis, the following features were associated with larger posttreatment declines in DLCO: pretreatment DLCO, gross tumor volume, lung and heart dosimetric data, and total radiation dose. Only pretreatment DLCO was associated with larger posttreatment declines in FEV1/VC. Conclusions: Lung diffusing capacity for carbon monoxide is reduced in the majority of patients after radiotherapy with modern techniques. Multiple factors, including gross tumor volume, preradiation lung function, and dosimetric parameters, are associated with the DLCO decline. Prospective studies are needed to better understand whether new radiation technology, such as proton beam therapy or

  8. Comparison of acute and subacute genitourinary and gastrointestinal adverse events of radiotherapy for prostate cancer using intensity-modulated radiation therapy, three-dimensional conformal radiation therapy, permanent implant brachytherapy and high-dose-rate brachytherapy

    NARCIS (Netherlands)

    Morimoto, Masahiro; Yoshioka, Yasuo; Konishi, Koji; Isohashi, Fumiaki; Takahashi, Yutaka; Ogata, Toshiyuki; Koizumi, Masahiko; Teshima, Teruki; Bijl, Henk P; van der Schaaf, Arjen; Langendijk, Johannes A; Ogawa, Kazuhiko

    2014-01-01

    AIMS AND BACKGROUND: To examine acute and subacute urinary and rectal toxicity in patients with localized prostate cancer monotherapeutically treated with the following four radiotherapeutic techniques: intensity-modulated radiation therapy, three-dimensional conformal radiation therapy, low-dose-ra

  9. Dosimetric analysis of tomotherapy-based intensity-modulated radiotherapy with and without bone marrow sparing for the treatment of cervical cancer

    Institute of Scientific and Technical Information of China (English)

    Fuli Zhang; Jianping Chen; Heliang He; Weidong Xu; Huayong Jiang; Yadi Wang ; Junmao Gao; Qingzhi Liu; Na Lu; Diandian Chen; Bo Yao

    2015-01-01

    Objective The aim of the study was to compare tomotherapy-based bone marrow-sparing intensity-mod-ulated radiotherapy (BMS-IMRT) with intensity-modulated radiotherapy (IMRT) without entering the pelvic bone marrow as a planning constraint in the treatment of cervical cancer after hysterectomy. Methods BMS-IMRT and IMRT plans were designed for a cohort of nine patients. The prescribed dose was 45 Gy in 1.8 Gy daily fractions, and 95% of the planned target volume received this dose. The doses were computed using a commercial y available treatment planning system with the convolution/superposi-tion algorithm. Plans were compared according to dose-volume histogram analysis in terms of planning target volume homogeneity and conformity indices (HI and CI) as wel as organ at risk dose and volume parameters. Results BMS-IMRT had advantages over IMRT in terms of CI, but was equivalent to the latter in HI. V5, V10, V20, V30, and V40 of pelvic bone marrow in BMS-IMRT decreased by 0.06%, 17.33%, 22.19%, 13.85%, and 16.46%, respectively, compared with IMRT. Except for V30 of the smal bowel and V30 and V40 of the bladder, no statistical y significant dif erences were found between BMS-IMRT and IMRT in the smal bowel, bladder, and rectum. Conclusion For cervical cancer patients receiving tomotherapy-based radiotherapy after hysterectomy, BMS-IMRT reduced pelvic bone marrow volume receiving low-dose radiation, and it may be conducive to preventing acute hematologic toxicity.

  10. Dosimetric comparison study between intensity modulated radiation therapy and three-dimensional conformal proton therapy for pelvic bone marrow sparing in the treatment of cervical cancer.

    Science.gov (United States)

    Song, William Y; Huh, Soon N; Liang, Yun; White, Greg; Nichols, R Charles; Watkins, W Tyler; Mundt, Arno J; Mell, Loren K

    2010-08-15

    The objective was to compare intensity-modulated radiation therapy (IMRT) with 3D conformal proton therapy (3DCPT) in the treatment of cervical cancer. In particular, each technique's ability to spare pelvic bone marrow (PBM) was of primary interest in this study. A total of six cervical cancer patients (3 postoperative and 3 intact) were planned and analyzed. All plans had uniform 1.0 cm CTV-PTV margin and satisfied the 95% PTV with 100% isodose (prescription dose = 45 Gy) coverage. Dose-volume histograms (DVH) were analyzed for comparison. The overall PTV and PBM volumes were 1035.9 ± 192.2 cc and 1151.4 ± 198.3 cc, respectively. In terms of PTV dose conformity index (DCI) and dose homogeneity index (DHI), 3DCPT was slightly superior to IMRT with 1.00 ± 0.001, 1.01 ± 0.02, and 1.10 ± 0.02, 1.13 ± 0.01, respectively. In addition, 3DCPT demonstrated superiority in reducing lower doses (i.e., V30 or less) to PBM, small bowel and bladder. Particularly in PBM, average V10 and V20 reductions of 10.8% and 7.4% (p = 0.001 and 0.04), respectively, were observed. However, in the higher dose range, IMRT provided better sparing (> V30). For example, in small bowel and PBM, average reductions in V45 of 4.9% and 10.0% (p = 0.048 and 0.008), respectively, were observed. Due to its physical characteristics such as low entrance dose, spread-out Bragg peak and finite particle range of protons, 3DCPT illustrated superior target coverage uniformity and sparing of the lower doses in PBM and other organs. Further studies are, however, needed to fully exploit the benefits of protons for general use in cervical cancer.

  11. Intensity-modulated pelvic radiation therapy and simultaneous integrated boost to the prostate area in patients with high-risk prostate cancer: a preliminary report of disease control.

    Science.gov (United States)

    Saracino, Biancamaria; Petrongari, Maria Grazia; Marzi, Simona; Bruzzaniti, Vicente; Sara, Gomellini; Arcangeli, Stefano; Arcangeli, Giorgio; Pinnarò, Paola; Giordano, Carolina; Ferraro, Anna Maria; Strigari, Lidia

    2014-10-01

    The aim of the study was to report the clinical results in patients with high-risk prostate cancer treated with pelvic intensity-modulated radiation therapy (IMRT) and simultaneous integrated boost (SIB) to the prostate area. A total of 110 patients entered our study, 37 patients presented with localized prostate cancer and radiological evidence of node metastases or ≥15% estimated risk of lymph node (LN) involvement, while 73 patients underwent postoperative adjuvant or salvage irradiation for biochemical or residual/recurrent disease, LN metastases, or high risk of harboring nodal metastases. All patients received androgen deprivation therapy (ADT) for 2 years. The median follow-up was 56.5 months. For the whole patient group, the 3- and 5-year freedom from biochemical failure were 82.6% and 74.6%, respectively, with a better outcome in patients treated with radical approach. The 3- and 5-year freedom from local failure were 94.4% and 90.2%, respectively, while the 3- and 5-year distant metastasis-free survival were 87.8% and 81.7%, respectively. For all study patients, the rate of freedom from G2 acute rectal, intestinal, and urinary toxicities was 60%, 77%, and 61%, respectively. There was no G3 acute toxicity, ≥G2 late intestinal toxicity, or G3 late urinary or rectal toxicity. The 3- and 5-year ≥G2 freedom from late rectal toxicity rate were 98% and 95%, respectively, while the 3- and 5-year ≥G2 freedom from late urinary toxicity rate were 95% and 88%, respectively. The study concludes that pelvic IMRT and SIB to the prostatic area in association with 2-year ADT was a well-tolerated technique, providing high disease control in patients with prostate cancer requiring LN treatment.

  12. Image-guided intensity modulated radiotherapy with helical tomotherapy for postoperative treatment of high-risk oral cavity cancer

    Directory of Open Access Journals (Sweden)

    Chen Yu-Jen

    2011-01-01

    Full Text Available Abstract Background The aim of this study was to assess the treatment results and toxicity profiles of helical tomotherapy (HT for postoperative high-risk oral cavity cancer. Methods From December 6, 2006 through October 9, 2009, 19 postoperative high-risk oral cavity cancer patients were enrolled. All of the patients received HT with (84% or without (16% chemotherapy. Results The median follow-up time was 17 months. The 2-year overall survival, disease-free survival, locoregional control, and distant metastasis-free rates were 94%, 84%, 92%, and 94%, respectively. The package of overall treatment time > 13 wk, the interval between surgery and radiation ≤ 6 wk, and the overall treatment time of radiation ≤ 7 wk was 21%, 84%, and 79%, respectively. The percentage of grade 3 mucositis, dermatitis, and leucopenia was 42%, 5% and 5%, respectively. Conclusions HT achieved encouraging clinical outcomes for postoperative high-risk oral cavity cancer patients with high compliance. A long-term follow-up study is needed to confirm these preliminary findings.

  13. Long-term outcomes from dose-escalated image-guided intensity-modulated radiotherapy with androgen deprivation: encouraging results for intermediate- and high-risk prostate cancer

    Directory of Open Access Journals (Sweden)

    Wilcox SW

    2014-08-01

    Full Text Available Shea W Wilcox,1,4 Noel J Aherne,2,4 Linus C Benjamin,1 Bosco Wu,1 Thomaz de Campos Silva,3 Craig S McLachlan,4 Michael J McKay,3,5 Andrew J Last,1 Thomas P Shakespeare1–4 1North Coast Cancer Institute, Port Macquarie, NSW, Australia; 2North Coast Cancer Institute, Coffs Harbour, NSW, Australia; 3North Coast Cancer Institute, Lismore, NSW, Australia; 4The University of New South Wales, Rural Clinical School, Sydney, NSW, Australia; 5The University of Sydney, Sydney, NSW, Australia Purpose: Dose-escalated (DE radiotherapy in the setting of localized prostate cancer has been shown to improve biochemical disease-free survival (bDFS in several studies. In the same group of patients, androgen deprivation therapy (ADT has been shown to confer a survival benefit when combined with radiotherapy doses of up to 70 Gy; however, there is currently little long-term data on patients who have received high-dose intensity-modulated radiotherapy (IMRT with ADT. We report the long-term outcomes in a large cohort of patients treated with the combination of DE image-guided IMRT (IG-IMRT and ADT. Methods and materials: Patients with localized prostate cancer were identified from a centralized database across an integrated cancer center. All patients received DE IG-IMRT, combined with ADT, and had a minimum follow up of 12 months post-radiotherapy. All relapse and toxicity data were collected prospectively. Actuarial bDFS, metastasis-free survival, prostate cancer-specific survival, and multivariate analyses were calculated using the SPSS v20.0 statistical package. Results: Seven hundred and eighty-two eligible patients were identified with a median follow up of 46 months. Overall, 4.3% of patients relapsed, 2.0% developed distant metastases, and 0.6% died from metastatic prostate cancer. At 5-years, bDFS was 88%, metastasis-free survival was 95%, and prostate cancer-specific survival was 98%. Five-year grade 2 genitourinary and gastrointestinal toxicity was 2

  14. Long-term Survival and Toxicity in Patients Treated With High-Dose Intensity Modulated Radiation Therapy for Localized Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Spratt, Daniel E.; Pei, Xin; Yamada, Josh; Kollmeier, Marisa A.; Cox, Brett [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Zelefsky, Michael J., E-mail: zelefskm@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2013-03-01

    Purpose: To report long-term survival and toxicity outcomes with the use of high-dose intensity modulated radiation therapy (IMRT) to 86.4 Gy for patients with localized prostate cancer. Methods and Materials: Between August 1997 and December 2008, 1002 patients were treated to a dose of 86.4 Gy using a 5-7 field IMRT technique. Patients were stratified by prognostic risk group based on National Comprehensive Cancer Network risk classification criteria. A total of 587 patients (59%) were treated with neoadjuvant and concurrent androgen deprivation therapy. The median follow-up for the entire cohort was 5.5 years (range, 1-14 years). Results: For low-, intermediate-, and high-risk groups, 7-year biochemical relapse-free survival outcomes were 98.8%, 85.6%, and 67.9%, respectively (P<.001), and distant metastasis-free survival rates were 99.4%, 94.1%, and 82.0% (P<.001), respectively. On multivariate analysis, T stage (P<.001), Gleason score (P<.001), and >50% of initial biopsy positive core (P=.001) were predictive for distant mestastases. No prostate cancer-related deaths were observed in the low-risk group. The 7-year prostate cancer-specific mortality (PCSM) rates, using competing risk analysis for intermediate- and high-risk groups, were 3.3% and 8.1%, respectively (P=.008). On multivariate analysis, Gleason score (P=.004), percentage of biopsy core positivity (P=.003), and T-stage (P=.033) were predictive for PCSM. Actuarial 7-year grade 2 or higher late gastrointestinal and genitourinary toxicities were 4.4% and 21.1%, respectively. Late grade 3 gastrointestinal and genitourinary toxicity was experienced by 7 patients (0.7%) and 22 patients (2.2%), respectively. Of the 427 men with full potency at baseline, 317 men (74%) retained sexual function at time of last follow-up. Conclusions: This study represents the largest cohort of patients treated with high-dose radiation to 86.4 Gy, using IMRT for localized prostate cancer, with the longest follow-up to date

  15. Propensity Score-based Comparison of Long-term Outcomes With 3-Dimensional Conformal Radiotherapy vs Intensity-Modulated Radiotherapy for Esophageal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Steven H., E-mail: SHLin@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wang Lu [Department of Biostatistics, University of Michigan, Ann Arbor, Michigan (United States); Myles, Bevan [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Thall, Peter F. [Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Hofstetter, Wayne L.; Swisher, Stephen G. [Department of Thoracic Surgery, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Ajani, Jaffer A. [Department of Gastrointestinal Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Cox, James D.; Komaki, Ritsuko; Liao Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2012-12-01

    Purpose: Although 3-dimensional conformal radiotherapy (3D-CRT) is the worldwide standard for the treatment of esophageal cancer, intensity modulated radiotherapy (IMRT) improves dose conformality and reduces the radiation exposure to normal tissues. We hypothesized that the dosimetric advantages of IMRT should translate to substantive benefits in clinical outcomes compared with 3D-CRT. Methods and Materials: An analysis was performed of 676 nonrandomized patients (3D-CRT, n=413; IMRT, n=263) with stage Ib-IVa (American Joint Committee on Cancer 2002) esophageal cancers treated with chemoradiotherapy at a single institution from 1998-2008. An inverse probability of treatment weighting and inclusion of propensity score (treatment probability) as a covariate were used to compare overall survival time, interval to local failure, and interval to distant metastasis, while accounting for the effects of other clinically relevant covariates. The propensity scores were estimated using logistic regression analysis. Results: A fitted multivariate inverse probability weighted-adjusted Cox model showed that the overall survival time was significantly associated with several well-known prognostic factors, along with the treatment modality (IMRT vs 3D-CRT, hazard ratio 0.72, P<.001). Compared with IMRT, 3D-CRT patients had a significantly greater risk of dying (72.6% vs 52.9%, inverse probability of treatment weighting, log-rank test, P<.0001) and of locoregional recurrence (P=.0038). No difference was seen in cancer-specific mortality (Gray's test, P=.86) or distant metastasis (P=.99) between the 2 groups. An increased cumulative incidence of cardiac death was seen in the 3D-CRT group (P=.049), but most deaths were undocumented (5-year estimate, 11.7% in 3D-CRT vs 5.4% in IMRT group, Gray's test, P=.0029). Conclusions: Overall survival, locoregional control, and noncancer-related death were significantly better after IMRT than after 3D-CRT. Although these results need

  16. Implementation of Constant Dose Rate and Constant Angular Spacing Intensity-modulated Arc Therapy for Cervical Cancer by Using a Conventional Linear Accelerator

    Science.gov (United States)

    Zhang, Ruo-Hui; Fan, Xiao-Mei; Bai, Wen-Wen; Cao, Yan-Kun

    2016-01-01

    Background: Volumetric-modulated arc therapy (VMAT) can only be implemented on the new generation linacs such as the Varian Trilogy® and Elekta Synergy®. This prevents most existing linacs from delivering VMAT. The purpose of this study was to investigate the feasibility of using a conventional linear accelerator delivering constant dose rate and constant angular spacing intensity-modulated arc therapy (CDR-CAS-IMAT) for treating cervical cancer. Methods: Twenty patients with cervical cancer previously treated with intensity-modulated radiation therapy (IMRT) using Varian Clinical 23EX were retreated using CDR-CAS-IMAT. The planning target volume (PTV) was set as 50.4 Gy in 28 fractions. Plans were evaluated based on the ability to meet the dose volume histogram. The homogeneity index (HI), target volume conformity index (CI), the dose to organs at risk, radiation delivery time, and monitor units (MUs) were also compared. The paired t-test was used to analyze the two data sets. All statistical analyses were performed using SPSS 19.0 software. Results: Compared to the IMRT group, the CDR-CAS-IMAT group showed better PTV CI (0.85 ± 0.03 vs. 0.81 ± 0.03, P = 0.001), clinical target volume CI (0.46 ± 0.05 vs. 0.43 ± 0.05, P = 0.001), HI (0.09±0.02 vs. 0.11 ± 0.02, P = 0.005) and D95 (5196.33 ± 28.24 cGy vs. 5162.63 ± 31.12 cGy, P = 0.000), and cord D2 (3743.8 ± 118.7 cGy vs. 3806.2 ± 98.7 cGy, P = 0.017) and rectum V40 (41.9 ± 6.1% vs. 44.2 ± 4.8%, P = 0.026). Treatment time (422.7 ± 46.7 s vs. 84.6 ± 7.8 s, P = 0.000) and the total plan Mus (927.4 ± 79.1 vs. 787.5 ± 78.5, P = 0.000) decreased by a factor of 0.8 and 0.15, respectively. The IMRT group plans were superior to the CDR-CAS-IMAT group plans considering decreasing bladder V50 (17.4 ± 4.5% vs. 16.6 ± 4.2%, P = 0.049), bowel V30 (39.6 ± 6.5% vs. 36.6 ± 7.5%, P = 0.008), and low-dose irradiation volume; there were no significant differences in other statistical indexes. Conclusions

  17. Implementation of Constant Dose Rate and Constant Angular Spacing Intensity-modulated Arc Therapy for Cervical Cancer by Using a Conventional Linear Accelerator

    Institute of Scientific and Technical Information of China (English)

    Ruo-Hui Zhang; Xiao-Mei Fan; Wen-Wen Bai; Yan-Kun Cao

    2016-01-01

    Background: Volumetric-modulated arc therapy (VMAT) can only be implemented on the new generation linacs such as the Varian Trilogy(R) and Elekta Synergy(R).This prevents most existing linacs from delivering VMAT.The purpose of this study was to investigate the feasibility of using a conventional linear accelerator delivering constant dose rate and constant angular spacing intensity-modulated arc therapy (CDR-CAS-IMAT) for treating cervical cancer.Methods: Twenty patients with cervical cancer previously treated with intensity-modulated radiation therapy (IMRT) using Varian Clinical 23EX were retreated using CDR-CAS-IMAT.The planning target volume (PTV) was set as 50.4 Gy in 28 fractions.Plans were evaluated based on the ability to meet the dose volume histogram.The homogeneity index (HI), target volume conformity index (CI), the dose to organs at risk, radiation delivery time, and monitor units (MUs) were also compared.The paired t-test was used to analyze the two data sets.All statistical analyses were performed using SPSS 19.0 software.Results: Compared to the IMRT group, the CDR-CAS-IMAT group showed better PTV CI (0.85 ± 0.03 vs.0.81 ± 0.03, P =0.001), clinical target volume CI (0.46 ± 0.05 vs.0.43 ± 0.05, P =0.001), HI (0.09±0.02 vs.0.11 ± 0.02, P =0.005) and D95 (5196.33 ± 28.24 cGy vs.5162.63 ± 31.12 cGy, P =0.000), and cord D2 (3743.8 ± 118.7 cGy vs.3806.2 ± 98.7 cGy, P =0.017) and rectum V40 (41.9 ± 6.1% vs.44.2 ± 4.8%, P =0.026).Treatment time (422.7 ± 46.7 s vs.84.6 ± 7.8 s, P =0.000) and the total plan Mus (927.4 ± 79.1 vs.787.5 ± 78.5, P =0.000) decreased by a factor of 0.8 and 0.15, respectively.The IMRT group plans were superior to the CDR-CAS-IMAT group plans considering decreasing bladder V50 (17.4 ± 4.5% vs.16.6 ± 4.2%, P =0.049), bowel V30 (39.6 ± 6.5% vs.36.6 ± 7.5%, P =0.008), and low-dose irradiation volume;there were no significant differences in other statistical indexes.Conclusions: Patients with cervical

  18. Skin dose differences between intensity-modulated radiation therapy and volumetric-modulated arc therapy and between boost and integrated treatment regimens for treating head and neck and other cancer sites in patients

    Energy Technology Data Exchange (ETDEWEB)

    Penoncello, Gregory P.; Ding, George X., E-mail: george.ding@vanderbilt.edu

    2016-04-01

    The purpose of this study was (1) to evaluate dose to skin between volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) treatment techniques for target sites in the head and neck, pelvis, and brain and (2) to determine if the treatment dose and fractionation regimen affect the skin dose between traditional sequential boost and integrated boost regimens for patients with head and neck cancer. A total of 19 patients and 48 plans were evaluated. The Eclipse (v11) treatment planning system was used to plan therapy in 9 patients with head and neck cancer, 5 patients with prostate cancer, and 5 patients with brain cancer with VMAT and static-field IMRT. The mean skin dose and the maximum dose to a contiguous volume of 2 cm{sup 3} for head and neck plans and brain plans and a contiguous volume of 5 cm{sup 3} for pelvis plans were compared for each treatment technique. Of the 9 patients with head and neck cancer, 3 underwent an integrated boost regimen. One integrated boost plan was replanned with IMRT and VMAT using a traditional boost regimen. For target sites located in the head and neck, VMAT reduced the mean dose and contiguous hot spot most noticeably in the shoulder region by 5.6% and 5.4%, respectively. When using an integrated boost regimen, the contiguous hot spot skin dose in the shoulder was larger on average than a traditional boost pattern by 26.5% and the mean skin dose was larger by 1.7%. VMAT techniques largely decrease the contiguous hot spot in the skin in the pelvis by an average of 36% compared with IMRT. For the same target coverage, VMAT can reduce the skin dose in all the regions of the body, but more noticeably in the shoulders in patients with head and neck and pelvis cancer. We also found that using integrated boost regimens in patients with head and neck cancer leads to higher shoulder skin doses compared with traditional boost regimens.

  19. The effect of uterine motion and uterine margins on target and normal tissue doses in intensity modulated radiation therapy of cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, J J; Weiss, E; Abayomi, O K; Siebers, J V; Dogan, N, E-mail: jjgordon@vcu.edu [Department of Radiation Oncology, Virginia Commonwealth University, PO Box 980058, Richmond, VA 23298 (United States)

    2011-05-21

    In intensity modulated radiation therapy (IMRT) of cervical cancer, uterine motion can be larger than cervix motion, requiring a larger clinical target volume to planning target volume (CTV-to-PTV) margin around the uterine fundus. This work simulates different motion models and margins to estimate the dosimetric consequences. A virtual study used image sets from ten patients. Plans were created with uniform margins of 1 cm (PTV{sub A}) and 2.4 cm (PTV{sub C}), and a margin tapering from 2.4 cm at the fundus to 1 cm at the cervix (PTV{sub B}). Three inter-fraction motion models (MM) were simulated. In MM1, all structures moved with normally distributed rigid body translations. In MM2, CTV motion was progressively magnified as one moved superiorly from the cervix to the fundus. In MM3, both CTV and normal tissue motion were magnified as in MM2, modeling the scenario where normal tissues move into the void left by the mobile uterus. Plans were evaluated using static and percentile DVHs. For a conventional margin (PTV{sub A}), quasi-realistic uterine motion (MM3) reduces fundus dose by about 5 Gy and increases normal tissue volumes receiving 30-50 Gy by {approx}5%. A tapered CTV-to-PTV margin can restore fundus and CTV doses, but will increase normal tissue volumes receiving 30-50 Gy by a further {approx}5%.

  20. Recent Research Progress in Intensity Modulated Radiation Therapy for Patients of Cervical Cancer%宫颈癌调强放射治疗研究新进展

    Institute of Scientific and Technical Information of China (English)

    刘爱荣; 赵凤菊

    2011-01-01

    放射治疗作为宫颈癌主要治疗方法之一,外照射逐渐用调强适形放疗(IMRT)代替四野箱式照射技术和盆腔前后对穿照射技术,而影像引导放疗开创了精确放疗到精准放疗的时代.内照射开始采用以二维影像为基础的治疗计划代替三维影像为基础的近距离放疗技术,为宫颈癌的放射治疗能更有效地减轻正常组织并发症,提高疗效打下更坚实的基础.目前,IMRT在妇科恶性肿瘤中应用时间相对较短且病例数较少,其安全性及有效性有待于进一步证实.但IMRT与三维高剂量率近距离放疗结合仍是放疗界关注的焦点.%Radiotherapy is one of the most common treatments for cervical cancer. Intensity modulated radiation therapy( IMRT )has gradually replaced four fields radiation technique or two fields A-P radiation therapy in EBRT , and the image-guide radiotherapy( ICRT )starts a new era in exact radiotherapy. Brachytherapy based on 2-D image has gradually been replaced by 3-D image. It is possible to further reduce the normal tissue complications probability and improve tumor control prohability in radiotherapy of uterine cervix cancer. At present , IMRT application in gynecologic malignancy has not heen long and case numher is small.The safety and efficacy of IMRT for cervical cancer need to he further confirmed. However, the combination of IMRT and 3-D HDR brachytherapy is still the focus of radiotherapy in cervical cancer.

  1. SU-F-BRD-01: A Novel 4D Robust Optimization Mitigates Interplay Effect in Intensity-Modulated Proton Therapy for Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W; Shen, J; Stoker, J; Bues, M [Mayo Clinic Arizona, Phoenix, AZ (United States); Schild, S; Wong, W [Mayo Clinic, Phoenix, Arizona (United States); Chang, J; Liao, Z; Wen, Z; Sahoo, N [MD Anderson Cancer Center, Houston, TX (United States); Herman, M [Mayo Clinic, Rochester, MN (United States); Mohan, R [UT MD Anderson Cancer Center, Houston, TX (United States)

    2015-06-15

    Purpose: To compare the impact of interplay effect on 3D and 4D robustly optimized intensity-modulated proton therapy (IMPT) plans to treat lung cancer. Methods: Two IMPT plans were created for 11 non-small-cell-lung-cancer cases with 6–14 mm spots. 3D robust optimization generated plans on average CTs with the internal gross tumor volume density overridden to deliver 66 CGyE in 33 fractions to the internal target volume (ITV). 4D robust optimization generated plans on 4D CTs with the delivery of prescribed dose to the clinical target volume (CTV). In 4D optimization, the CTV of individual 4D CT phases received non-uniform doses to achieve a uniform cumulative dose. Dose evaluation software was developed to model time-dependent spot delivery to incorporate interplay effect with randomized starting phases of each field per fraction. Patient anatomy voxels were mapped from phase to phase via deformable image registration to score doses. Indices from dose-volume histograms were used to compare target coverage, dose homogeneity, and normal-tissue sparing. DVH indices were compared using Wilcoxon test. Results: Given the presence of interplay effect, 4D robust optimization produced IMPT plans with better target coverage and homogeneity, but slightly worse normal tissue sparing compared to 3D robust optimization (unit: Gy) [D95% ITV: 63.5 vs 62.0 (p=0.014), D5% - D95% ITV: 6.2 vs 7.3 (p=0.37), D1% spinal cord: 29.0 vs 29.5 (p=0.52), Dmean total lung: 14.8 vs 14.5 (p=0.12), D33% esophagus: 33.6 vs 33.1 (p=0.28)]. The improvement of target coverage (D95%,4D – D95%,3D) was related to the ratio RMA3/(TVx10−4), with RMA and TV being respiratory motion amplitude (RMA) and tumor volume (TV), respectively. Peak benefit was observed at ratios between 2 and 10. This corresponds to 125 – 625 cm3 TV with 0.5-cm RMA. Conclusion: 4D optimization produced more interplay-effect-resistant plans compared to 3D optimization. It is most effective when respiratory motion is modest

  2. Comparative cost-effectiveness of stereotactic body radiation therapy versus intensity-modulated and proton radiation therapy for localized prostate cancer.

    Directory of Open Access Journals (Sweden)

    Anju eParthan

    2012-08-01

    Full Text Available Objective. To determine the cost-effectiveness of several external beam radiation treatment modalities for the treatment of patients with localized prostate cancer.Methods. A lifetime Markov model incorporated the probabilities of experiencing treatment-related long-term toxicity or death. Toxicity probabilities were derived from published sources using meta-analytical techniques. Utilities and costs in the model were obtained from publically available secondary sources. The model calculated quality-adjusted life expectancy and expected lifetime cost per patient, and derived ratios of incremental cost per quality-adjusted life year (QALY gained between treatments. Analyses were conducted from both a payer and societal perspectives. One-way and probabilistic sensitivity analyses were performed.Results. Compared to intensity modulated radiation therapy (IMRT and proton beam therapy (PT, stereotactic body radiation therapy (SBRT was less costly and resulted in more QALYs. Sensitivity analyses showed that the conclusions in the base-case scenario were robust with respect to variations in toxicity and cost parameters consistent with available evidence. At a threshold of $50,000/QALY, SBRT was cost effective in 75%, and 94% of probabilistic simulations compared to IMRT and PT, respectively, from a payer perspective. From a societal perspective, SBRT was cost-effective in 75%, and 96% of simulations compared to IMRT and PT, respectively, at a threshold of $50,000/QALY. In threshold analyses, SBRT was less expensive with better outcomes compared to IMRT at toxicity rates 23% greater than the SBRT base-case rates. Conclusions. Based on the assumption that each treatment modality results in equivalent long-term efficacy, SBRT is a cost-effective strategy resulting in improved quality-adjusted survival compared to IMRT and PT for the treatment of localized prostate cancer.

  3. Duodenal and Other Gastrointestinal Toxicity in Cervical and Endometrial Cancer Treated With Extended-Field Intensity Modulated Radiation Therapy to Paraaortic Lymph Nodes

    Energy Technology Data Exchange (ETDEWEB)

    Poorvu, Philip D. [Department of Radiation Oncology, Brigham and Women' s Hospital and Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts (United States); Sadow, Cheryl A. [Department of Radiology, Brigham and Women' s Hospital, and Harvard Medical School, Boston, Massachusetts (United States); Townamchai, Kanokpis; Damato, Antonio L. [Department of Radiation Oncology, Brigham and Women' s Hospital and Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts (United States); Viswanathan, Akila N., E-mail: aviswanathan@lroc.harvard.edu [Department of Radiation Oncology, Brigham and Women' s Hospital and Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts (United States)

    2013-04-01

    Purpose: To characterize the rates of acute and late duodenal and other gastrointestinal (GI) toxicities among patients treated for cervical and endometrial cancers with extended-field intensity modulated radiation therapy (EF-IMRT) to the paraaortic nodes and to analyze dose-volume relationships of GI toxicities. Methods and Materials: Fifty-three patients with endometrial or cervical cancer underwent EF-IMRT to the paraaortic nodes, of whom 46 met the inclusion criteria for GI toxicity and 45 for duodenal toxicity analysis. The median prescribed dose to the paraaortic nodes was 54 Gy (range, 41.4-65 Gy). The 4 duodenal segments, whole duodenum, small bowel loops, peritoneum, and peritoneum plus retroperitoneal segments of colon were contoured retrospectively, and dosimetric analysis was performed to identify dose-volume relationships to grade ≥3 acute (<90 day) and late (≥90 day) GI toxicity. Results: Only 3/46 patients (6.5%) experienced acute grade ≥3 GI toxicity and 3/46 patients (6.5%) experienced late grade ≥3 GI toxicity. The median dose administered to these 6 patients was 50.4 Gy. One of 12 patients who received 63 to 65 Gy at the level of the renal hilum experienced grade 3 GI toxicity. Dosimetric analysis of patients with and without toxicity revealed no differences between the mean absolute or fractional volumes at any 5-Gy interval between 5 Gy and the maximum dose. None of the patients experienced duodenal toxicity. Conclusions: Treatment of paraaortic nodes with IMRT is associated with low rates of GI toxicities and no duodenal-specific toxicity, including patients treated with concurrent chemotherapy. This technique may allow sufficient dose sparing of the bowel to enable safe dose escalation to at least 65 Gy.

  4. Four-Week Neoadjuvant Intensity-Modulated Radiation Therapy With Concurrent Capecitabine and Oxaliplatin in Locally Advanced Rectal Cancer Patients: A Validation Phase II Trial

    Energy Technology Data Exchange (ETDEWEB)

    Arbea, Leire, E-mail: larbea@unav.es [Department of Oncology, Clinica Universidad de Navarra, Navarra (Spain); Martinez-Monge, Rafael; Diaz-Gonzalez, Juan A.; Moreno, Marta; Rodriguez, Javier [Department of Oncology, Clinica Universidad de Navarra, Navarra (Spain); Hernandez, Jose Luis [Department of General Surgery, Clinica Universidad de Navarra, Navarra (Spain); Sola, Jesus Javier [Department of Pathology, Clinica Universidad de Navarra, Navarra (Spain); Ramos, Luis Isaac [Department of Oncology, Clinica Universidad de Navarra, Navarra (Spain); Subtil, Jose Carlos [Department of Gastroenterology, Clinica Universidad de Navarra, Navarra (Spain); Nunez, Jorge [Department of Preventive Medicine and Public Health, Clinica Universidad de Navarra, Navarra (Spain); Chopitea, Ana; Cambeiro, Mauricio; Gaztanaga, Miren; Garcia-Foncillas, Jesus; Aristu, Javier [Department of Oncology, Clinica Universidad de Navarra, Navarra (Spain)

    2012-06-01

    Purpose: To validate tolerance and pathological complete response rate (pCR) of a 4-week preoperative course of intensity-modulated radiation therapy (IMRT) with concurrent capecitabine and oxaliplatin (CAPOX) in patients with locally advanced rectal cancer. Methods and Materials: Patients with T3 to T4 and/or N+ rectal cancer received preoperative IMRT (47.5 Gy in 19 fractions) with concurrent capecitabine (825 mg/m{sup 2} b.i.d., Monday to Friday) and oxaliplatin (60 mg/m{sup 2} on Days 1, 8, and 15). Surgery was scheduled 4 to 6 weeks after the completion of chemoradiation. Primary end points were toxicity and pathological response rate. Local control (LC), disease-free survival (DFS), and overall survival (OS) were also analyzed. Results: A total of 100 patients were evaluated. Grade 1 to 2 proctitis was observed in 73 patients (73%). Grade 3 diarrhea occurred in 9% of the patients. Grade 3 proctitis in 18% of the first 50 patients led to reduction of the dose per fraction to 47.5 Gy in 20 treatments. The rate of Grade 3 proctitis decreased to 4% thereafter (odds ratio, 0.27). A total of 99 patients underwent surgery. A pCR was observed in 13% of the patients, major response (96-100% of histological response) in 48%, and pN downstaging in 78%. An R0 resection was performed in 97% of the patients. After a median follow-up of 55 months, the LC, DFS, and OS rates were 100%, 84%, and 87%, respectively. Conclusions: Preoperative CAPOX-IMRT therapy (47.5 Gy in 20 fractions) is feasible and safe, and produces major pathological responses in approximately 50% of patients.

  5. Five-year Local Control in a Phase II Study of Hypofractionated Intensity Modulated Radiation Therapy With an Incorporated Boost for Early Stage Breast Cancer

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    Freedman, Gary M., E-mail: Gary.Freedman@uphs.upenn.edu [Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Anderson, Penny R. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Bleicher, Richard J. [Department of Surgical Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Litwin, Samuel; Li Tianyu [Department of Biostatistics, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Swaby, Ramona F. [Department of Medical Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Ma, Chang-Ming Charlie; Li Jinsheng [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Sigurdson, Elin R. [Department of Surgical Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Watkins-Bruner, Deborah [School of Nursing, Emory University, Atlanta, Georgia (United States); Morrow, Monica [Department of Surgical Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Goldstein, Lori J. [Department of Medical Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States)

    2012-11-15

    Purpose: Conventional radiation fractionation of 1.8-2 Gy per day for early stage breast cancer requires daily treatment for 6-7 weeks. We report the 5-year results of a phase II study of intensity modulated radiation therapy (IMRT), hypofractionation, and incorporated boost that shortened treatment time to 4 weeks. Methods and Materials: The study design was phase II with a planned accrual of 75 patients. Eligibility included patients aged {>=}18 years, Tis-T2, stage 0-II, and breast conservation. Photon IMRT and an incorporated boost was used, and the whole breast received 2.25 Gy per fraction for a total of 45 Gy, and the tumor bed received 2.8 Gy per fraction for a total of 56 Gy in 20 treatments over 4 weeks. Patients were followed every 6 months for 5 years. Results: Seventy-five patients were treated from December 2003 to November 2005. The median follow-up was 69 months. Median age was 52 years (range, 31-81). Median tumor size was 1.4 cm (range, 0.1-3.5). Eighty percent of tumors were node negative; 93% of patients had negative margins, and 7% of patients had close (>0 and <2 mm) margins; 76% of cancers were invasive ductal type: 15% were ductal carcinoma in situ, 5% were lobular, and 4% were other histology types. Twenty-nine percent of patients 29% had grade 3 carcinoma, and 20% of patients had extensive in situ carcinoma; 11% of patients received chemotherapy, 36% received endocrine therapy, 33% received both, and 20% received neither. There were 3 instances of local recurrence for a 5-year actuarial rate of 2.7%. Conclusions: This 4-week course of hypofractionated radiation with incorporated boost was associated with excellent local control, comparable to historical results of 6-7 weeks of conventional whole-breast fractionation with sequential boost.

  6. A Knowledge-Based Approach to Improving and Homogenizing Intensity Modulated Radiation Therapy Planning Quality Among Treatment Centers: An Example Application to Prostate Cancer Planning

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    Good, David [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Lo, Joseph [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Department of Radiology and Departments of Biomedical Engineering and Electrical and Computer Engineering, Duke University, Durham, North Carolina (United States); Lee, W. Robert [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Wu, Q. Jackie; Yin, Fang-Fang [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Das, Shiva K., E-mail: shiva.das@duke.edu [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States)

    2013-09-01

    Purpose: Intensity modulated radiation therapy (IMRT) treatment planning can have wide variation among different treatment centers. We propose a system to leverage the IMRT planning experience of larger institutions to automatically create high-quality plans for outside clinics. We explore feasibility by generating plans for patient datasets from an outside institution by adapting plans from our institution. Methods and Materials: A knowledge database was created from 132 IMRT treatment plans for prostate cancer at our institution. The outside institution, a community hospital, provided the datasets for 55 prostate cancer cases, including their original treatment plans. For each “query” case from the outside institution, a similar “match” case was identified in the knowledge database, and the match case’s plan parameters were then adapted and optimized to the query case by use of a semiautomated approach that required no expert planning knowledge. The plans generated with this knowledge-based approach were compared with the original treatment plans at several dose cutpoints. Results: Compared with the original plan, the knowledge-based plan had a significantly more homogeneous dose to the planning target volume and a significantly lower maximum dose. The volumes of the rectum, bladder, and femoral heads above all cutpoints were nominally lower for the knowledge-based plan; the reductions were significantly lower for the rectum. In 40% of cases, the knowledge-based plan had overall superior (lower) dose–volume histograms for rectum and bladder; in 54% of cases, the comparison was equivocal; in 6% of cases, the knowledge-based plan was inferior for both bladder and rectum. Conclusions: Knowledge-based planning was superior or equivalent to the original plan in 95% of cases. The knowledge-based approach shows promise for homogenizing plan quality by transferring planning expertise from more experienced to less experienced institutions.

  7. Comparison of 3D conformal radiotherapy vs. intensity modulated radiation therapy (IMRT) of a stomach cancer treatment;Comparacion dosimetrica de radioterapia conformal 3D versus radioterapia de intensidad modulada (IMRT) de un tratamiento de cancer de estomago

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    Bernui de V, Maria Giselle; Cardenas, Augusto; Vargas, Carlos [Hospital Nacional Carlos Alberto Seguin Escobedo (ESSALUD), Arequipa (Peru). Servicio de Radioterapia

    2009-07-01

    The purpose of this work was to compare the dosimetry in 3D Conformal Radiotherapy with Intensity Modulated Radiation Therapy (IMRT) in a treatment of stomach cancer. For this comparison we selected a patient who underwent subtotal gastrectomy and D2 dissection for a T3N3 adenocarcinoma Mx ECIIIB receiving treatment under the scheme Quimio INT 0116 - in adjuvant radiotherapy. In the treatment plan was contouring the Clinical Target Volume (CTV) and the Planning Target Volume (PTV) was generated from the expansion of 1cm of the CTV, the risky organs contouring were: the liver, kidneys and spinal cord, according to the consensus definition of volumes in gastric cancer. The 3D Conformal Radiotherapy planning is carried out using 6 half beams following the Leong Trevol technique; for the IMRT plan was used 8 fields, the delivery technique is step-and-shoot. In both cases the fields were coplanar, isocentric and the energy used was 18 MV. Intensity Modulated Radiation Therapy (IMRT), in this case has proved to be a good treatment alternative to the technique of 3D Conformal Radiotherapy; the dose distributions with IMRT have better coverage of PTV and positions of the hot spots, as well as the kidneys volume that received higher doses to 2000 cGy is lower, but the decrease in dose to the kidneys is at the expense of increased dose in other organs like the liver. (author)

  8. Influence of collimator rotation on dose distribution and delivery in intensity modulated radiation therapy for parotid cancer

    Directory of Open Access Journals (Sweden)

    Seema Sharma

    2015-01-01

    Full Text Available Purpose: To evaluate the influence of collimator rotation in IMRT planning with respect to the target coverage and dose to critical structures. In addition, the delivery efficiency of desired fluence with collimator rotation is assessed.Methods: The computed tomography (CT datasets of 5 patients with parotid cancer were employed for this study. Dynamic IMRT plans were generated with a dose prescription of 60 Gy in 30 fractions. IMRT plans were generated with five unilateral fields using 6MV X-rays. Four different plans were generated for each patient by keeping the collimator angle at 0, 30, 60, and 90 degree. All plans were analyzed using dose volume histogram. Conformity index (CI and heterogeneity index (HI were calculated. The total monitor units (MU required to deliver one fraction were noted and compared. To verify the delivery efficiency; the measured fluence on IBA I’mRT MatriXX ionization chamber array detector was compared with the TPS dose plan with 2D gamma evaluation.Results: There is not much difference in the PTV Dmax and Dmean with respect to the different collimator angles. The PTV coverage is best at collimator angle of 0 degree. A slight reduction in CI was observed with plans at other collimator angles as compared to 0 degree. The HI values were almost similar for plans with collimator angle 0, 30, and 60 degree. The plan with 90 degree collimator showed a slightly higher heterogeneity for the PTV. A slight reduction in the average Dmax to spinal cord was observed for the plan with collimator angle 30 degree as compared to other angles whereas maximum value of Dmax to spinal cord was at collimator angle 60 degree. No clinically relevant difference was observed among the plans with respect to brainstem and mandible Dmax. An increase in average of oral cavity Dmax and Dmean was observed for collimator angle 60 and 90 degree as compared to collimator angle 0 and 30 degree. Not much difference was observed with respect to Dmax

  9. RapidArc, intensity modulated photon and proton techniques for recurrent prostate cancer in previously irradiated patients: a treatment planning comparison study

    Directory of Open Access Journals (Sweden)

    Ratib Osman

    2009-09-01

    Full Text Available Abstract Background A study was performed comparing volumetric modulated arcs (RA and intensity modulation (with photons, IMRT, or protons, IMPT radiation therapy (RT for patients with recurrent prostate cancer after RT. Methods Plans for RA, IMRT and IMPT were optimized for 7 patients. Prescribed dose was 56 Gy in 14 fractions. The recurrent gross tumor volume (GTV was defined on 18F-fluorocholine PET/CT scans. Plans aimed to cover at least 95% of the planning target volume with a dose > 50.4 Gy. A maximum dose (DMax of 61.6 Gy was allowed to 5% of the GTV. For the urethra, DMax was constrained to 37 Gy. Rectal DMedian was 90 parameters. Results Tumor coverage (GTV and PTV was improved with RA (V95% 92.6 ± 7.9 and 83.7 ± 3.3%, when compared to IMRT (V95% 88.6 ± 10.8 and 77.2 ± 2.2%. The corresponding values for IMPT were intermediate for the GTV (V95% 88.9 ± 10.5% and better for the PTV (V95%85.6 ± 5.0%. The percentages of rectal and urethral volumes receiving intermediate doses (35 Gy were significantly decreased with RA (5.1 ± 3.0 and 38.0 ± 25.3% and IMPT (3.9 ± 2.7 and 25.1 ± 21.1%, when compared to IMRT (9.8 ± 5.3 and 60.7 ± 41.7%. CI90 was 1.3 ± 0.1 for photons and 1.6 ± 0.2 for protons. Integral Dose was 1.1 ± 0.5 Gy*cm3 *105 for IMPT and about a factor three higher for all photon's techniques. Conclusion RA and IMPT showed improvements in conformal avoidance relative to fixed beam IMRT for 7 patients with recurrent prostate cancer. IMPT showed further sparing of organs at risk.

  10. Split-field vs extended-field intensity-modulated radiation therapy plans for oropharyngeal cancer: Which spares the larynx? Which spares the thyroid?

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    Yu, Yao; Chen, Josephine [Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA (United States); Leary, Celeste I. [Department of Radiation Medicine, Oregon Health Sciences University, Portland, OR (United States); Shugard, Erin [Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA (United States); Yom, Sue S., E-mail: yoms@radonc.ucsf.edu [Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA (United States); Department of Otolaryngology—Head and Neck Surgery, University of California, San Francisco, San Francisco, CA (United States)

    2016-07-01

    Radiation of the low neck can be accomplished using split-field intensity-modulated radiation therapy (sf-IMRT) or extended-field intensity-modulated radiation therapy (ef-IMRT). We evaluated the effect of these treatment choices on target coverage and thyroid and larynx doses. Using data from 14 patients with cancers of the oropharynx, we compared the following 3 strategies for radiating the low neck: (1) extended-field IMRT, (2) traditional split-field IMRT with an initial cord-junction block to 40 Gy, followed by a full-cord block to 50 Gy, and (3) split-field IMRT with a full-cord block to 50 Gy. Patients were planned using each of these 3 techniques. To facilitate comparison, extended-field plans were normalized to deliver 50 Gy to 95% of the neck volume. Target coverage was assessed using the dose to 95% of the neck volume (D{sub 95}). Mean thyroid and larynx doses were computed. Extended-field IMRT was used as the reference arm; the mean larynx dose was 25.7 ± 7.4 Gy, and the mean thyroid dose was 28.6 ± 2.4 Gy. Split-field IMRT with 2-step blocking reduced laryngeal dose (mean larynx dose 15.2 ± 5.1 Gy) at the cost of a moderate reduction in target coverage (D{sub 95} 41.4 ± 14 Gy) and much higher thyroid dose (mean thyroid dose 44.7 ± 3.7 Gy). Split-field IMRT with initial full-cord block resulted in greater laryngeal sparing (mean larynx dose 14.2 ± 5.1 Gy) and only a moderately higher thyroid dose (mean thyroid dose 31 ± 8 Gy) but resulted in a significant reduction in target coverage (D{sub 95} 34.4 ± 15 Gy). Extended-field IMRT comprehensively covers the low neck and achieves acceptable thyroid and laryngeal sparing. Split-field IMRT with a full-cord block reduces laryngeal doses to less than 20 Gy and spares the thyroid, at the cost of substantially reduced coverage of the low neck. Traditional 2-step split-field IMRT similarly reduces the laryngeal dose but also reduces low-neck coverage and delivers very high doses to the thyroid.

  11. Rapid Arc, helical tomotherapy, sliding window intensity modulated radiotherapy and three dimensional conformal radiation for localized prostate cancer: A dosimetric comparison

    Directory of Open Access Journals (Sweden)

    Rajesh A Kinhikar

    2014-01-01

    Full Text Available Objective: The objective of this study was to investigate the potential role of RapidArc (RA compared with helical tomotherapy (HT, sliding window intensity modulated radiotherapy (SW IMRT and three-dimensional conformal radiation therapy (3D CRT for localized prostate cancer. Materials and Methods: Prescription doses ranged from 60 Gy to planning target volume (PTV and 66.25 Gy for clinical target volume prostate (CTV-P over 25-30 fractions. PTV and CTV-P coverage were evaluated by conformity index (CI and homogeneity index (HI. Organ sparing comparison was done with mean doses to rectum and bladder. Results: CI 95 were 1.0 ± 0.01 (RA, 0.99 ± 0.01 (HT, 0.97 ± 0.02 (IMRT, 0.98 ± 0.02 (3D CRT for PTV and 1.0 ± 0.00 (RA, HT, SW IMRT and 3D CRT for CTV-P. HI was 0.11 ± 0.03 (RA, 0.16 ± 0.08 (HT, 0.12 ± 0.03 (IMRT, 0.06 ± 0.01 (3D CRT for PTV and 0.03 ± 0.00 (RA, 0.05 ± 0.01 (HT, 0.03 ± 0.01 (SW IMRT and 3D CRT for CTV-P. Mean dose to bladder were 23.68 ± 13.23 Gy (RA, 24.55 ± 12.51 Gy (HT, 19.82 ± 11.61 Gy (IMRT and 23.56 ± 12.81 Gy (3D CRT, whereas mean dose to rectum was 36.85 ± 12.92 Gy (RA, 33.18 ± 11.12 Gy (HT, IMRT and 38.67 ± 12.84 Gy (3D CRT. Conclusion: All studied intensity-modulated techniques yield treatment plans of significantly improved quality when compared with 3D CRT, with HT providing best organs at risk sparing and RA being the most efficient treatment option, reducing treatment time to 1.45-3.7 min and monitor unit to <400 for a 2 Gy fraction.

  12. Impact of Dose to the Bladder Trigone on Long-Term Urinary Function After High-Dose Intensity Modulated Radiation Therapy for Localized Prostate Cancer

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    Ghadjar, Pirus; Zelefsky, Michael J.; Spratt, Daniel E. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Munck af Rosenschöld, Per; Oh, Jung Hun; Hunt, Margie [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Kollmeier, Marisa [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Happersett, Laura; Yorke, Ellen; Deasy, Joseph O. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Jackson, Andrew, E-mail: jacksona@mskcc.org [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2014-02-01

    Purpose: To determine the potential association between genitourinary (GU) toxicity and planning dose–volume parameters for GU pelvic structures after high-dose intensity modulated radiation therapy in localized prostate cancer patients. Methods and Materials: A total of 268 patients who underwent intensity modulated radiation therapy to a prescribed dose of 86.4 Gy in 48 fractions during June 2004-December 2008 were evaluated with the International Prostate Symptom Score (IPSS) questionnaire. Dose–volume histograms of the whole bladder, bladder wall, urethra, and bladder trigone were analyzed. The primary endpoint for GU toxicity was an IPSS sum increase ≥10 points over baseline. Univariate and multivariate analyses were done by the Kaplan-Meier method and Cox proportional hazard models, respectively. Results: Median follow-up was 5 years (range, 3-7.7 years). Thirty-nine patients experienced an IPSS sum increase ≥10 during follow-up; 84% remained event free at 5 years. After univariate analysis, lower baseline IPSS sum (P=.006), the V90 of the trigone (P=.006), and the maximal dose to the trigone (P=.003) were significantly associated with an IPSS sum increase ≥10. After multivariate analysis, lower baseline IPSS sum (P=.009) and increased maximal dose to the trigone (P=.005) remained significantly associated. Seventy-two patients had both a lower baseline IPSS sum and a higher maximal dose to the trigone and were defined as high risk, and 68 patients had both a higher baseline IPSS sum and a lower maximal dose to the trigone and were defined as low risk for development of an IPSS sum increase ≥10. Twenty-one of 72 high-risk patients (29%) and 5 of 68 low-risk patients (7%) experienced an IPSS sum increase ≥10 (P=.001; odds ratio 5.19). Conclusions: The application of hot spots to the bladder trigone was significantly associated with relevant changes in IPSS during follow-up. Reduction of radiation dose to the lower bladder and specifically the

  13. SU-E-P-48: Evaluation of Intensity Modulated Radiotherapy (IMRT) with Three Different Commercial Planning Systems for the Treatment of Cervical Cancer

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    Liu, D; Chi, Z; Yang, H; Miao, M; Jing, Z [The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei (China)

    2015-06-15

    Purpose: To investigate the performances of three commercial treatment planning systems (TPS) for intensity modulated radiotherapy (IMRT) optimization regarding cervical cancer. Methods: For twenty cervical cancer patients, three IMRT plans were retrospectively re-planned: one with Pinnacle TPS,one with Oncentra TPS and on with Eclipse TPS. The total prescribed dose was 50.4 Gy delivered for PTV and 58.8 Gy for PTVnd by simultaneous integrated boost technique. The treatments were delivered using the Varian 23EX accelerator. All optimization schemes generated clinically acceptable plans. They were evaluated based on target coverage, homogeneity (HI) and conformity (CI). The organs at risk (OARs) were analyzed according to the percent volume under some doses and the maximum doses. The statistical method of the collected data of variance analysis was used to compare the difference among the quality of plans. Results: IMRT with Eclipse provided significant better HI, CI and all the parameters of PTV. However, the trend was not extension to the PTVnd, it was still significant better at mean dose, D50% and D98%, but plans with Oncentra showed significant better in the hight dosage volume, such as maximum dose and D2%. For the bladder wall, there were not notable difference among three groups, although Pinnacle and Oncentra systems provided a little lower dose sparing at V50Gy of bladder and rectal wall and V40Gy of bladder wall, respectively. V40Gy of rectal wall (p=0.037), small intestine (p=0.001 for V30Gy, p=0.010 for maximum dose) and V50Gy of right-femoral head (p=0.019) from Eclipse plans showed significant better than other groups. Conclusion: All SIB-IMRT plans were clinically acceptable which were generated by three commercial TPSs. The plans with Eclipse system showed advantages over the plans with Oncentra and Pinnacle system in the overwhelming majority of the dose coverage for targets and dose sparing of OARs in cervical cancer.

  14. Normal Tissue Complication Probability Analysis of Acute Gastrointestinal Toxicity in Cervical Cancer Patients Undergoing Intensity Modulated Radiation Therapy and Concurrent Cisplatin

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    Simpson, Daniel R.; Song, William Y. [Center for Advanced Radiotherapy Technologies, Department of Radiation Oncology, University of California San Diego, La Jolla, CA (United States); Moiseenko, Vitali [Department of Medical Physics, Vancouver Cancer Centre, BC (Canada); Rose, Brent S.; Yashar, Catheryn M.; Mundt, Arno J. [Center for Advanced Radiotherapy Technologies, Department of Radiation Oncology, University of California San Diego, La Jolla, CA (United States); Mell, Loren K., E-mail: lmell@ucsd.edu [Center for Advanced Radiotherapy Technologies, Department of Radiation Oncology, University of California San Diego, La Jolla, CA (United States)

    2012-05-01

    Purpose: To test the hypothesis that increased bowel radiation dose is associated with acute gastrointestinal (GI) toxicity in cervical cancer patients undergoing concurrent chemotherapy and intensity-modulated radiation therapy (IMRT), using a previously derived normal tissue complication probability (NTCP) model. Methods: Fifty patients with Stage I-III cervical cancer undergoing IMRT and concurrent weekly cisplatin were analyzed. Acute GI toxicity was graded using the Radiation Therapy Oncology Group scale, excluding upper GI events. A logistic model was used to test correlations between acute GI toxicity and bowel dosimetric parameters. The primary objective was to test the association between Grade {>=}2 GI toxicity and the volume of bowel receiving {>=}45 Gy (V{sub 45}) using the logistic model. Results: Twenty-three patients (46%) had Grade {>=}2 GI toxicity. The mean (SD) V{sub 45} was 143 mL (99). The mean V{sub 45} values for patients with and without Grade {>=}2 GI toxicity were 176 vs. 115 mL, respectively. Twenty patients (40%) had V{sub 45} >150 mL. The proportion of patients with Grade {>=}2 GI toxicity with and without V{sub 45} >150 mL was 65% vs. 33% (p = 0.03). Logistic model parameter estimates V50 and {gamma} were 161 mL (95% confidence interval [CI] 60-399) and 0.31 (95% CI 0.04-0.63), respectively. On multivariable logistic regression, increased V{sub 45} was associated with an increased odds of Grade {>=}2 GI toxicity (odds ratio 2.19 per 100 mL, 95% CI 1.04-4.63, p = 0.04). Conclusions: Our results support the hypothesis that increasing bowel V{sub 45} is correlated with increased GI toxicity in cervical cancer patients undergoing IMRT and concurrent cisplatin. Reducing bowel V{sub 45} could reduce the risk of Grade {>=}2 GI toxicity by approximately 50% per 100 mL of bowel spared.

  15. Intensity-Modulated Radiotherapy Causes Fewer Side Effects than Three-Dimensional Conformal Radiotherapy When Used in Combination With Brachytherapy for the Treatment of Prostate Cancer

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    Forsythe, Kevin; Blacksburg, Seth [Department of Radiation Oncology, Mount Sinai School of Medicine, New York, NY (United States); Stone, Nelson [Department of Urology, Mount Sinai School of Medicine, New York, NY (United States); Stock, Richard G., E-mail: richard.stock@moutsinai.org [Department of Radiation Oncology, Mount Sinai School of Medicine, New York, NY (United States)

    2012-06-01

    Purpose: To measure the benefits of intensity-modulated radiotherapy (IMRT) compared with three-dimensional conformal radiotherapy (3D-CRT) when used in combination with brachytherapy for the treatment of prostate cancer. Methods and Materials: We conducted a retrospective review of all patients with localized prostate cancer who received external-beam radiotherapy (EBRT) in combination with brachytherapy with at least 1 year follow-up (n = 812). Combination therapy consisted of {sup 103}Pd or {sup 125}I implant, followed by a course of EBRT. From 1993 to March 2003 521 patients were treated with 3D-CRT, and from April 2003 to March 2009 291 patients were treated with IMRT. Urinary symptoms were prospectively measured with the International Prostate Symptom Score questionnaire with a single quality of life (QOL) question; rectal bleeding was assessed per the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer Late Radiation Morbidity Scoring Schema. The Pearson {chi}{sup 2} test was used to compare toxicities experienced by patients who were treated with either IMRT or 3D-CRT. Logistic regression analyses were also performed to rule out possible confounding factors. Results: Within the first 3 months after treatment, patients treated with 3D-CRT scored their urinary symptoms as follows: 19% mild, 44% moderate, and 37% severe; patients treated with IMRT scored their urinary symptoms as follows: 36% mild, 47% moderate, and 17% severe (p < 0.001). The 3D-CRT patients rated their QOL as follows: 35% positive, 20% neutral, and 45% negative; IMRT patients rated their QOL as follows: 51% positive, 18% neutral, and 31% negative (p < 0.001). After 1 year of follow-up there was no longer any difference in urinary morbidity between the two groups. Logistic regression confirmed the differences in International Prostate Symptom Score and QOL in the acute setting (p < 0.001 for both). Grade {>=}2 rectal bleeding was reported by 11% of 3D

  16. Accelerated Partial Breast Irradiation Is Safe and Effective Using Intensity-Modulated Radiation Therapy in Selected Early-Stage Breast Cancer

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    Lewin, Alan A., E-mail: alanl@baptisthealth.net [Department of Radiation Oncology, Baptist Hospital of Miami, Miami, FL (United States); Derhagopian, Robert [Department of Surgery, Baptist Hospital of Miami, Miami, FL (United States); Saigal, Kunal; Panoff, Joseph E. [Department of Radiation Oncology, University of Miami, Miami, FL (United States); Abitbol, Andre; Wieczorek, D. Jay; Mishra, Vivek [Department of Radiation Oncology, Baptist Hospital of Miami, Miami, FL (United States); Reis, Isildinha; Ferrell, Annapoorna [Division of Biostatistics, University of Miami, Miami, FL (United States); Moreno, Lourdes [Department of Radiation Oncology, Baptist Hospital of Miami, Miami, FL (United States); Takita, Cristiane [Department of Radiation Oncology, University of Miami, Miami, FL (United States)

    2012-04-01

    Purpose: To report the feasibility, toxicity, cosmesis, and efficacy of using intensity-modulated radiation therapy (IMRT) with respiratory gating to deliver accelerated partial breast irradiation (APBI) in selected Stage I/II breast cancer after breast-conserving surgery. Methods and Materials: Eligible patients with node-negative Stage I/II breast cancer were prospectively enrolled in an institutional review board approved protocol to receive APBI using IMRT after breast-conserving surgery. The target volume was treated at 3.8 Gy/fraction twice daily for 5 days, to a total dose of 38 Gy. Results: Thirty-six patients were enrolled for a median follow-up time of 44.8 months. The median tumor size was 0.98 cm (range, 0.08-3 cm). The median clinical target volume (CTV) treated was 71.4 cc (range, 19-231 cc), with the mean dose to the CTV being 38.96 Gy. Acute toxicities included Grade 1 erythema in 44% of patients and Grade 2 in 6%, Grade 1 hyperpigmentation in 31% of patients and Grade 2 in 3%, and Grade 1 breast/chest wall tenderness in 14% of patients. No Grade 3/4 acute toxicities were observed. Grade 1 and 2 late toxicities as edema, fibrosis, and residual hyperpigmentation occurred in 14% and 11% of patients, respectively; Grade 3 telangiectasis was observed in 3% of patients. The overall cosmetic outcome was considered 'excellent' or 'good' by 94% of patients and 97% when rated by the physician, respectively. The local control rate was 97%; 1 patient died of a non-cancer-related cause. Conclusions: APBI can be safely and effectively administered using IMRT. In retrospective analysis, IMRT enabled the achievement of normal tissue dose constraints as outlined by Radiation Therapy Oncology Group 04-13/NSABP B-13 while providing excellent conformality for the CTV. Local control and cosmesis have remained excellent at current follow-up, with acceptable rates of acute/late toxicities. Our data suggest that cosmesis is dependent on target volume

  17. Patient-Reported Voice and Speech Outcomes After Whole-Neck Intensity Modulated Radiation Therapy and Chemotherapy for Oropharyngeal Cancer: Prospective Longitudinal Study

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    Vainshtein, Jeffrey M. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Griffith, Kent A. [Center for Cancer Biostatistics, University of Michigan School of Public Health, Ann Arbor, Michigan (United States); Feng, Felix Y.; Vineberg, Karen A. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Chepeha, Douglas B. [Department of Otolaryngology–Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan (United States); Eisbruch, Avraham, E-mail: eisbruch@umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)

    2014-08-01

    Purpose: To describe voice and speech quality changes and their predictors in patients with locally advanced oropharyngeal cancer treated on prospective clinical studies of organ-preserving chemotherapy–intensity modulated radiation therapy (chemo-IMRT). Methods and Materials: Ninety-one patients with stage III/IV oropharyngeal cancer were treated on 2 consecutive prospective studies of definitive chemoradiation using whole-field IMRT from 2003 to 2011. Patient-reported voice and speech quality were longitudinally assessed from before treatment through 24 months using the Communication Domain of the Head and Neck Quality of Life (HNQOL-C) instrument and the Speech question of the University of Washington Quality of Life (UWQOL-S) instrument, respectively. Factors associated with patient-reported voice quality worsening from baseline and speech impairment were assessed. Results: Voice quality decreased maximally at 1 month, with 68% and 41% of patients reporting worse HNQOL-C and UWQOL-S scores compared with before treatment, and improved thereafter, recovering to baseline by 12-18 months on average. In contrast, observer-rated larynx toxicity was rare (7% at 3 months; 5% at 6 months). Among patients with mean glottic larynx (GL) dose ≤20 Gy, >20-30 Gy, >30-40 Gy, >40-50 Gy, and >50 Gy, 10%, 32%, 25%, 30%, and 63%, respectively, reported worse voice quality at 12 months compared with before treatment (P=.011). Results for speech impairment were similar. Glottic larynx dose, N stage, neck dissection, oral cavity dose, and time since chemo-IMRT were univariately associated with either voice worsening or speech impairment. On multivariate analysis, mean GL dose remained independently predictive for both voice quality worsening (8.1%/Gy) and speech impairment (4.3%/Gy). Conclusions: Voice quality worsening and speech impairment after chemo-IMRT for locally advanced oropharyngeal cancer were frequently reported by patients, underrecognized by clinicians, and

  18. Randomized phase II trial of urethral sparing intensity modulated radiation therapy in low-risk prostate cancer: implications for focal therapy

    Directory of Open Access Journals (Sweden)

    Vainshtein Jeffrey

    2012-06-01

    Full Text Available Abstract Background Low-risk prostate cancer (PCa patients have excellent outcomes, with treatment modality often selected by perceived effects on quality of life. Acute urinary symptoms are common during external beam radiotherapy (EBRT, while chronic symptoms have been linked to urethral dose. Since most low-risk PCa occurs in the peripheral zone (PZ, we hypothesized that EBRT using urethral sparing intensity modulated radiation therapy (US-IMRT could improve urinary health-related quality of life (HRQOL while maintaining high rates of PCa control. Methods Patients with National Comprehensive Cancer Network (NCCN defined low-risk PCa with no visible lesion within 5 mm of the prostatic urethra on MRI were randomized to US-IMRT or standard (S- IMRT. Prescription dose was 75.6 Gy in 41 fractions to the PZ + 3–5 mm for US-IMRT and to the prostate + 3 mm for S-IMRT. For US-IMRT, mean proximal and distal urethral doses were limited to 65 Gy and 74 Gy, respectively. HRQOL was assessed using the Expanded Prostate Cancer Index (EPIC Quality of Life questionnaire. The primary endpoint was change in urinary HRQOL at 3 months. Results From June 2004 to November 2006, 16 patients were randomized, after which a futility analysis concluded that continued accrual was unlikely to demonstrate a difference in the primary endpoint. Mean change in EPIC urinary HRQOL at 3 months was −0.5 ± 11.2 in the US-IMRT arm and +3.9 ± 15.3 in the S-IMRT arm (p = 0.52. Median PSA nadir was higher in the US-IMRT arm (1.46 vs. 0.78, p = 0.05. At 4.7 years median follow-up, three US-IMRT and no S-IMRT patients experienced PSA failure (p = 0.06; HR 8.8, 95% CI 0.9–86. Two out of 3 patients with PSA failure had biopsy-proven local failure, both located contralateral to the original site of disease. Conclusions Compared with S-IMRT, US-IMRT failed to improve urinary HRQOL and resulted in higher PSA nadir and inferior biochemical

  19. Intensity-Modulated Radiotherapy for Pancreatic Adenocarcinoma

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    Abelson, Jonathan A.; Murphy, James D.; Minn, Ann Yuriko; Chung, Melody [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Fisher, George A.; Ford, James M.; Kunz, Pamela [Department of Medical Oncology, Stanford University, Stanford, CA (United States); Norton, Jeffrey A.; Visser, Brendan C.; Poultsides, George A. [Department of Surgical Oncology, Stanford University, Stanford, CA (United States); Koong, Albert C. [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Chang, Daniel T., E-mail: dtchang@stanford.edu [Department of Radiation Oncology, Stanford University, Stanford, CA (United States)

    2012-03-15

    Purpose: To report the outcomes and toxicities in patients treated with intensity-modulated radiotherapy (IMRT) for pancreatic adenocarcinoma. Methods and Materials: Forty-seven patients with pancreatic adenocarcinoma were treated with IMRT between 2003 and 2008. Of these 47 patients, 29 were treated adjuvantly and 18 definitively. All received concurrent 5-fluorouracil chemotherapy. The treatment plans were optimized such that 95% of the planning target volume received the prescription dose. The median delivered dose for the adjuvant and definitive patients was 50.4 and 54.0 Gy, respectively. Results: The median age at diagnosis was 63.9 years. For adjuvant patients, the 1- and 2-year overall survival rate was 79% and 40%, respectively. The 1- and 2-year recurrence-free survival rate was 58% and 17%, respectively. The local-regional control rate at 1 and 2 years was 92% and 80%, respectively. For definitive patients, the 1-year overall survival, recurrence-free survival, and local-regional control rate was 24%, 16%, and 64%, respectively. Four patients developed Grade 3 or greater acute toxicity (9%) and four developed Grade 3 late toxicity (9%). Conclusions: Survival for patients with pancreatic cancer remains poor. A small percentage of adjuvant patients have durable disease control, and with improved therapies, this proportion will increase. Systemic therapy offers the greatest opportunity. The present results have demonstrated that IMRT is well tolerated. Compared with those who received three-dimensional conformal radiotherapy in previously reported prospective clinical trials, patients with pancreatic adenocarcinoma treated with IMRT in our series had improved acute toxicity.

  20. Intensity-modulated whole abdomen irradiation following adjuvant carboplatin/taxane chemotherapy for FIGO stage III ovarian cancer. Four-year outcomes

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    Rochet, Nathalie; Lindel, Katja; Katayama, Sonja; Schubert, Kai; Herfarth, Klaus; Harms, Wolfgang; Debus, Juergen [Heidelberg Institute of Radiation Oncology (HIRO), Heidelberg (Germany); University of Heidelberg, Department of Radiation Oncology, Heidelberg (Germany); Schneeweiss, Andreas [University of Heidelberg, Nationales Centrum fuer Tumorerkrankungen (NCT), Heidelberg (Germany); Sohn, Christoph [University of Heidelberg, Department of Gynecology, Heidelberg (Germany)

    2015-07-15

    A prospective study to assess toxicity and survival outcomes after intensity-modulated whole-abdominal irradiation (IM-WAI) following surgery and adjuvant intravenous carboplatin/taxane chemotherapy in advanced FIGO stage III ovarian cancer. Between 2006 and 2009, 16 patients with optimally resected FIGO stage III ovarian cancer, who had received six cycles of adjuvant carboplatin/taxane chemotherapy were treated with consolidation IM-WAI. Radiotherapy was delivered to a total dose of 30 Gy in 1.5-Gy fractions, using step-and-shoot (n = 3) or helical tomotherapy (n = 13). The first 10 patients were treated within a phase I trial; the following patients received the same treatment modality. The target volume included the entire peritoneal cavity, the diaphragm, the liver capsule, and the pelvic and para-aortic node regions. Organs at risk were kidneys, liver, heart, and bone marrow. Median follow-up was 44 months (range 19.2-67.2 months). No grade 4 toxicities occurred during IM-WAI. Common Toxicity Criteria for Adverse Events (CTCAE) grade 3 toxicities were: diarrhea (25 %), leucopenia (19 %), nausea/vomiting (6 %), and thrombocytopenia (6 %). No toxicity-related treatment break was necessary. Small bowel obstruction occurred in a total of 6 patients: in 3 cases (19 %) due to postsurgical adhesions and in 3 cases due to local tumor recurrence (19 %). Median recurrence-free survival (RFS) was 27.6 months (95 % confidence interval, CI = 24-44 months) and median overall survival (OS) was 42.1 months (95 %CI = 17-68 months). The peritoneal cavity was the most frequent site of initial failure. Consolidation IM-WAI following surgery and adjuvant chemotherapy is feasible and can be performed with manageable acute and late toxicity. The favorable RFS outcome is promising and justifies further clinical trials. (orig.) [German] Es wurden Akut- und Langzeittoxizitaet sowie Ueberlebensdaten der konsolidierenden intensitaetsmodulierten Ganzabdomenbestrahlung (''intensity-modulated

  1. Prospective Preference Assessment of Patients' Willingness to Participate in a Randomized Controlled Trial of Intensity-Modulated Radiotherapy Versus Proton Therapy for Localized Prostate Cancer

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    Shah, Anand [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Efstathiou, Jason A.; Paly, Jonathan J. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Halpern, Scott D. [Department of Medicine, University of Pennsylvania, Philadelphia, PA (United States); Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA (United States); Center for Bioethics, University of Pennsylvania, Philadelphia, PA (United States); Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, PA (United States); Bruner, Deborah W. [Winship Cancer Institute, Emory University, Atlanta, GA (United States); Christodouleas, John P. [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Coen, John J. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Deville, Curtiland; Vapiwala, Neha [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Shipley, William U.; Zietman, Anthony L. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Hahn, Stephen M. [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Bekelman, Justin E., E-mail: bekelman@uphs.upenn.edu [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, PA (United States)

    2012-05-01

    Purpose: To investigate patients' willingness to participate (WTP) in a randomized controlled trial (RCT) comparing intensity-modulated radiotherapy (IMRT) with proton beam therapy (PBT) for prostate cancer (PCa). Methods and Materials: We undertook a qualitative research study in which we prospectively enrolled patients with clinically localized PCa. We used purposive sampling to ensure a diverse sample based on age, race, travel distance, and physician. Patients participated in a semi-structured interview in which they reviewed a description of a hypothetical RCT, were asked open-ended and focused follow-up questions regarding their motivations for and concerns about enrollment, and completed a questionnaire assessing characteristics such as demographics and prior knowledge of IMRT or PBT. Patients' stated WTP was assessed using a 6-point Likert scale. Results: Forty-six eligible patients (33 white, 13 black) were enrolled from the practices of eight physicians. We identified 21 factors that impacted patients' WTP, which largely centered on five major themes: altruism/desire to compare treatments, randomization, deference to physician opinion, financial incentives, and time demands/scheduling. Most patients (27 of 46, 59%) stated they would either 'definitely' or 'probably' participate. Seventeen percent (8 of 46) stated they would 'definitely not' or 'probably not' enroll, most of whom (6 of 8) preferred PBT before their physician visit. Conclusions: A substantial proportion of patients indicated high WTP in a RCT comparing IMRT and PBT for PCa.

  2. RapidArc radiotherapy planning for prostate cancer: Single-arc and double-arc techniques vs. intensity-modulated radiotherapy

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    Sze, Henry C.K., E-mail: szeck@ha.org.hk [Department of Clinical Oncology, Pamela Youde Nethersole Eastern Hospital, Hong Kong (Hong Kong); Lee, Michael C.H.; Hung, Wai-Man; Yau, Tsz-Kok; Lee, Anne W.M. [Department of Clinical Oncology, Pamela Youde Nethersole Eastern Hospital, Hong Kong (Hong Kong)

    2012-04-01

    RapidArc is a novel technique using arc radiotherapy aiming to achieve intensity-modulated radiotherapy (IMRT)-quality radiotherapy plans with shorter treatment time. This study compared the dosimetric quality and treatment efficiency of single-arc (SA) vs. double-arc (DA) and IMRT in the treatment of prostate cancer. Fourteen patients were included in the analysis. The planning target volume (PTV), which contained the prostate gland and proximal seminal vesicles, received 76 Gy in 38 fractions. Seven-field IMRT, SA, and DA plans were generated for each patient. Dosimetric quality in terms of the minimum PTV dose, PTV hotspot, inhomogeneity, and conformity index; and sparing of rectum, bladder, and femoral heads as measured by V70, V-40, and V20 (% of volume receiving >70 Gy, 40 Gy, and 20 Gy, respectively), treatment efficiency as assessed by monitor units (MU) and treatment time were compared. All plan objectives were met satisfactorily by all techniques. DA achieved the best dosimetric quality with the highest minimum PTV dose, lowest hotspot, and the best homogeneity and conformity. It was also more efficient than IMRT. SA achieved the highest treatment efficiency with the lowest MU and shortest treatment time. The mean treatment time for a 2-Gy fraction was 4.80 min, 2.78 min, and 1.30 min for IMRT, DA, and SA, respectively. However, SA also resulted in the highest rectal dose. DA could improve target volume coverage and reduce treatment time and MU while maintaining equivalent normal tissue sparing when compared with IMRT. SA achieved the greatest treatment efficiency but with the highest rectal dose, which was nonetheless within tolerable limits. For busy units with high patient throughput, SA could be an acceptable option.

  3. Long-Term Clinical Outcome of Intensity-Modulated Radiotherapy for Inoperable Non-Small Cell Lung Cancer: The MD Anderson Experience

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    Jiang Zhiqin [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai (China); Yang Kunyu [Cancer Centre, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Komaki, Ritsuko; Wei Xiong [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Tucker, Susan L. [Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Zhuang Yan; Martel, Mary K.; Vedam, Sastray; Balter, Peter [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Zhu Guangying [Department of Radiation Oncology, Peking University School of Oncology, Beiijng Cancer Hospital and Institute, Beijing (China); Gomez, Daniel [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Lu, Charles [Department of Thoracic Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Mohan, Radhe [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Cox, James D. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Liao Zhongxing, E-mail: zliao@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States)

    2012-05-01

    Purpose: In 2007, we published our initial experience in treating inoperable non-small-cell lung cancer (NSCLC) with intensity-modulated radiation therapy (IMRT). The current report is an update of that experience with long-term follow-up. Methods and Materials: Patients in this retrospective review were 165 patients who began definitive radiotherapy, with or without chemotherapy, for newly diagnosed, pathologically confirmed NSCLC to a dose of {>=}60 Gy from 2005 to 2006. Early and late toxicities assessed included treatment-related pneumonitis (TRP), pulmonary fibrosis, esophagitis, and esophageal stricture, scored mainly according to the Common Terminology Criteria for Adverse Events 3.0. Other variables monitored were radiation-associated dermatitis and changes in body weight and Karnofsky performance status. The Kaplan-Meier method was used to compute survival and freedom from radiation-related acute and late toxicities as a function of time. Results: Most patients (89%) had Stage III to IV disease. The median radiation dose was 66 Gy given in 33 fractions (range, 60-76 Gy, 1.8-2.3 Gy per fraction). Median overall survival time was 1.8 years; the 2-year and 3-year overall survival rates were 46% and 30%. Rates of Grade {>=}3 maximum TRP (TRP{sub max}) were 11% at 6 months and 14% at 12 months. At 18 months, 86% of patients had developed Grade {>=}1 maximum pulmonary fibrosis (pulmonary fibrosis{sub max}) and 7% Grade {>=}2 pulmonary fibrosis{sub max}. The median times to maximum esophagitis (esophagitis{sub max}) were 3 weeks (range, 1-13 weeks) for Grade 2 and 6 weeks (range, 3-13 weeks) for Grade 3. A higher percentage of patients who experienced Grade 3 esophagitis{sub max} later developed Grade 2 to 3 esophageal stricture. Conclusions: In our experience, using IMRT to treat NSCLC leads to low rates of pulmonary and esophageal toxicity, and favorable clinical outcomes in terms of survival.

  4. Correlating planned radiation dose to the cochlea with primary site and tumor stage in patients with head and neck cancer treated with intensity-modulated radiation therapy

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    Zhang, Jeanette; Qureshi, Muhammad M.; Kovalchuk, Nataliya; Truong, Minh Tam, E-mail: mitruong@bu.edu

    2014-04-01

    The aim of the study was to determine tumor characteristics that predict higher planned radiation (RT) dose to the cochlea in patients with head and neck cancer (HNC) treated with intensity-modulated radiotherapy (IMRT). From 2004 to 2012, 99 patients with HNC underwent definitive IMRT to a median dose of 69.96 Gy in 33 fractions, with the right and left cochlea-vestibular apparatus contoured for IMRT optimization as avoidance structures. If disease involvement was adjacent to the cochlea, preference was given to tumor coverage by prescription dose. Descriptive statistics were calculated for dose-volume histogram planning data, and mean planning dose to the cochlea (from left or right cochlea, receiving the greater amount of RT dose) was correlated to primary site and tumor stage. Mean (standard deviation) cochlear volume was 1.0 (0.60) cm{sup 3} with maximum and mean planned doses of 31.9 (17.5) Gy and 22.1 (13.7) Gy, respectively. Mean planned dose (Gy) to cochlea by tumor site was as follows: oral cavity (18.6, 14.4), oropharynx (21.7, 9.1), nasopharynx (36.3, 10.4), hypopharynx (14.9, 7.1), larynx (2.1, 0.62), others including the parotid gland, temporal bone, and paranasal sinus (33.6, 24.0), and unknown primary (25.6, 6.7). Average mean planned dose (Gy) to the cochlea in T0-T2 and T3-T4 disease was 22.0 and 29.2 Gy, respectively (p = 0.019). By site, a significant difference was noted for nasopharynx and others (31.6 and 50.7, p = 0.012) but not for oropharynx, oral cavity, and hypopharynx. Advanced T category predicted for higher mean cochlear dose, particularly for nasopharyngeal, parotid gland, temporal bone, and paranasal sinus HNC sites.

  5. An investigation of intensity-modulated radiation therapy versus conventional two-dimensional and 3D-conformal radiation therapy for early stage larynx cancer

    Directory of Open Access Journals (Sweden)

    Gomez Daniel

    2010-08-01

    Full Text Available Abstract Introduction Intensity modulated radiation therapy (IMRT has been incorporated at several institutions for early stage laryngeal cancer (T1/T2N0M0, but its utility is controversial. Methods In three representative patients, multiple plans were generated: 1 Conventional 2D planning, with the posterior border placed at either the anterior aspect ("tight" plan or the mid-vertebral body ("loose" plan, 2 3D planning, utilizing both 1.0 and 0.5 cm margins for the planning target volume (PTV, and 3 IMRT planning, utilizing the same margins as the 3D plans. A dosimetric comparison was performed for the target volume, spinal cord, arytenoids, and carotid arteries. The prescription dose was 6300 cGy (225 cGy fractions, and the 3D and IMRT plans were normalized to this dose. Results For PTV margins of 1.0 cm and 0.5 cm, the D95 of the 2D tight/loose plans were 3781/5437 cGy and 5372/5869 cGy, respectively (IMRT/3D plans both 6300 cGy. With a PTV margin of 1.0 cm, the mean carotid artery dose was 2483/5671/5777/4049 cGy in the 2D tight, 2D loose, 3D, and IMRT plans, respectively. When the PTV was reduced to 0.5 cm, the the mean carotid artery dose was 2483/5671/6466/2577 cGy to the above four plans, respectively. The arytenoid doses were similar between the four plans, and spinal cord doses were well below tolerance. Conclusions IMRT provides a more ideal dose distribution compared to 2D treatment and 3D planning in regards to mean carotid dose. We therefore recommend IMRT in select cases when the treating physician is confident with the GTV.

  6. Fully Automated Simultaneous Integrated Boosted-Intensity Modulated Radiation Therapy Treatment Planning Is Feasible for Head-and-Neck Cancer: A Prospective Clinical Study

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    Wu Binbin, E-mail: binbin.wu@gunet.georgetown.edu [Department of Radiation Oncology and Molecular Radiation Science, Johns Hopkins University, Baltimore, Maryland (United States); Department of Radiation Medicine, Georgetown University Hospital, Washington, DC (United States); McNutt, Todd [Department of Radiation Oncology and Molecular Radiation Science, Johns Hopkins University, Baltimore, Maryland (United States); Zahurak, Marianna [Department of Oncology Biostatistics, Johns Hopkins University, Baltimore, Maryland (United States); Simari, Patricio [Autodesk Research, Toronto, ON (Canada); Pang, Dalong [Department of Radiation Medicine, Georgetown University Hospital, Washington, DC (United States); Taylor, Russell [Department of Computer Science, Johns Hopkins University, Baltimore, Maryland (United States); Sanguineti, Giuseppe [Department of Radiation Oncology and Molecular Radiation Science, Johns Hopkins University, Baltimore, Maryland (United States)

    2012-12-01

    Purpose: To prospectively determine whether overlap volume histogram (OVH)-driven, automated simultaneous integrated boosted (SIB)-intensity-modulated radiation therapy (IMRT) treatment planning for head-and-neck cancer can be implemented in clinics. Methods and Materials: A prospective study was designed to compare fully automated plans (APs) created by an OVH-driven, automated planning application with clinical plans (CPs) created by dosimetrists in a 3-dose-level (70 Gy, 63 Gy, and 58.1 Gy), head-and-neck SIB-IMRT planning. Because primary organ sparing (cord, brain, brainstem, mandible, and optic nerve/chiasm) always received the highest priority in clinical planning, the study aimed to show the noninferiority of APs with respect to PTV coverage and secondary organ sparing (parotid, brachial plexus, esophagus, larynx, inner ear, and oral mucosa). The sample size was determined a priori by a superiority hypothesis test that had 85% power to detect a 4% dose decrease in secondary organ sparing with a 2-sided alpha level of 0.05. A generalized estimating equation (GEE) regression model was used for statistical comparison. Results: Forty consecutive patients were accrued from July to December 2010. GEE analysis indicated that in APs, overall average dose to the secondary organs was reduced by 1.16 (95% CI = 0.09-2.33) with P=.04, overall average PTV coverage was increased by 0.26% (95% CI = 0.06-0.47) with P=.02 and overall average dose to the primary organs was reduced by 1.14 Gy (95% CI = 0.45-1.8) with P=.004. A physician determined that all APs could be delivered to patients, and APs were clinically superior in 27 of 40 cases. Conclusions: The application can be implemented in clinics as a fast, reliable, and consistent way of generating plans that need only minor adjustments to meet specific clinical needs.

  7. Re-irradiation of unresectable recurrent head and neck cancer: using Helical Tomotherapy as image-guided intensity-modulated radiotherapy

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    Jeong, Songmi; Yoo, Eun Jung; Kim, Ji Yoon; Han, Chi Wha; Kim, Ki Jun; Kay, Chul Seung [The Catholic University of Korea College of Medicine, Seoul (Korea, Republic of)

    2013-12-15

    Re-irradiation (re-RT) is considered a treatment option for inoperable locoregionally recurrent head and neck cancer (HNC) after prior radiotherapy. We evaluated the efficacy and safety of re-RT using Helical Tomotherapy as image-guided intensity-modulated radiotherapy in recurrent HNC. Patients diagnosed with recurrent HNC and received re-RT were retrospectively reviewed. Primary endpoint was overall survival (OS) and secondary endpoints were locoregional control and toxicities. The median follow-up period of total 9 patients was 18.7 months (range, 4.1 to 76 months) and that of 3 alive patients was 49 months (range, 47 to 76 months). Median dose of first radiotherapy and re-RT was 64.8 and 47.5 Gy10. Median cumulative dose of the two courses of radiotherapy was 116.3 Gy10 (range, 91.8 to 128.9 Gy10) while the median interval between the two courses of radiation was 25 months (range, 4 to 137 months). The response rate after re-RT of the evaluated 8 patients was 75% (complete response, 4; partial response, 2). Median locoregional relapse-free survival after re-RT was 11.9 months (range, 3.4 to 75.1 months) and 5 patients eventually presented with treatment failure (in-field failure, 2; in- and out-field failure, 2; out-field failure, 1). Median OS of the 8 patients was 20.3 months (range, 4.1 to 75.1 months). One- and two-year OS rates were 62.5% and 50%, respectively. Grade 3 leucopenia developed in one patient as acute toxicity, and grade 2 osteonecrosis and trismus as chronic toxicity in another patient. Re-RT using Helical Tomotherapy for previously irradiated patients with unresectable locoregionally recurrent HNC may be a feasible treatment option with long-term survival and acceptable toxicities.

  8. Intensity modulated radiotherapy as neoadjuvant chemoradiation for the treatment of patients with locally advanced pancreatic cancer. Outcome analysis and comparison with a 3D-treated patient cohort

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    Combs, S.E.; Habermehl, D.; Kessel, K.; Brecht, I. [Univ. Hospital of Heidelberg (Germany). Dept. of Radiation Oncology; Bergmann, F.; Schirmacher, P. [Univ. Hospital of Heidelberg (Germany). Dept. of Pathology; Werner, J.; Buechler, M.W. [Univ. Hospital of Heidelberg (Germany). Dept. of Surgery; Jaeger, D. [National Center for Tumor Diseases (NCT), Heidelberg (Germany); Debus, J. [Univ. Hospital of Heidelberg (Germany). Dept. of Radiation Oncology; Deutsches Krebsforschungszentrum (DKFZ), Heidelberg (Germany). Clinical Cooperation Unit Radiation Oncology

    2013-09-15

    Background: To evaluate outcome after intensity modulated radiotherapy (IMRT) compared to 3D conformal radiotherapy (3D-RT) as neoadjuvant treatment in patients with locally advanced pancreatic cancer (LAPC). Materials and methods: In total, 57 patients with LAPC were treated with IMRT and chemotherapy. A median total dose of 45 Gy to the PTV {sub baseplan} and 54 Gy to the PTV {sub boost} in single doses of 1.8 Gy for the PTV {sub baseplan} and median single doses of 2.2 Gy in the PTV {sub boost} were applied. Outcomes were evaluated and compared to a large cohort of patients treated with 3D-RT. Results: Overall treatment was well tolerated in all patients and IMRT could be completed without interruptions. Median overall survival was 11 months (range 5-37.5 months). Actuarial overall survival at 12 and 24 months was 36 % and 8 %, respectively. A significant impact on overall survival could only be observed for a decrease in CA 19-9 during treatment, patients with less pre-treatment CA 19-9 than the median, as well as weight loss during treatment. Local progression-free survival was 79 % after 6 months, 39 % after 12 months, and 13 % after 24 months. No factors significantly influencing local progression-free survival could be identified. There was no difference in overall and progression-free survival between 3D-RT and IMRT. Secondary resectability was similar in both groups (26 % vs. 28 %). Toxicity was comparable and consisted mainly of hematological toxicity due to chemotherapy. Conclusion: IMRT leads to a comparable outcome compared to 3D-RT in patients with LAPC. In the future, the improved dose distribution, as well as advances in image-guided radiotherapy (IGRT) techniques, may improve the use of IMRT in local dose escalation strategies to potentially improve outcome. (orig.)

  9. Residual deficits in quality of life one year after intensity-modulated radiotherapy for patients with locally advanced head and neck cancer. Results of a prospective study

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    Tribius, Silke; Raguse, Marieclaire; Voigt, Christian; Petersen, Cordula; Kruell, Andreas [University Medical Center Hamburg-Eppendorf, Department of Radiation Oncology, Hamburg (Germany); Muenscher, Adrian [University Medical Center Hamburg-Eppendorf, Department of Otorhinolaryngology and Head and Neck Surgery, Hamburg (Germany); Groebe, Alexander [University Medical Center Hamburg-Eppendorf, Department of Maxillofacial Surgery, Hamburg (Germany); Bergelt, Corinna [University Medical Center Hamburg-Eppendorf, Department of Medical Psychology, Hamburg (Germany); Singer, Susanne [University Medical Center Mainz, Institute of Medical Biostatistics, Epidemiology and Informatics (IMBEI), Mainz (Germany)

    2015-03-08

    Patients with locally advanced head and neck cancer (LAHNC) undergo life-changing treatments that can seriously affect quality of life (QoL). This prospective study examined the key QoL domains during the first year after intensity-modulated radiotherapy (IMRT) and identified predictors of these changes in order to improve patient outcomes. A consecutive series of patients with LAHNC completed the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core module (QLQ-C30) and the HNC-specific QLQ-HN35 before (t0) and at the end (t1) of definitive or adjuvant IMRT, then at 6-8 weeks (t2), 6 months (t3), and 1 year (t4) after IMRT. Patients (n = 111) completing questionnaires at all five time points were included (baseline response rate: 99 %; dropout rate between t0 and t4: 5 %). QoL deteriorated in all domains during IMRT and improved slowly during the first year thereafter. Many domains recovered to baseline values after 1 year but problems with smelling and tasting, dry mouth, and sticky saliva remained issues at this time. Increases in problems with sticky saliva were greater after 1 year in patients with definitive versus adjuvant IMRT (F = 3.5, P = 0.05). QoL in patients with LAHNC receiving IMRT takes approximately 1 year to return to baseline; some domains remain compromised after 1 year. Although IMRT aims to maintain function and QoL, patients experience long-term dry mouth and sticky saliva, particularly following definitive IMRT. Patients should be counseled at the start of therapy to reduce disappointment with the pace of recovery. (orig.) [German] Die Therapie von Patienten mit lokal fortgeschrittenen Kopf-Hals-Tumoren (LFKHT) geht mit einschneidenden Veraenderungen einher und beeinflusst die Lebensqualitaet (LQ) erheblich. Diese prospektive Studie untersucht die LQ waehrend des ersten Jahres nach intensitaetsmodulierter Strahlentherapie (IMRT) und hat Praediktoren dieser Veraenderungen herausgearbeitet, um

  10. Comparison and evaluation of volumetric modulated arc therapy and intensity modulated radiation therapy plans for postoperative radiation therapy of prostate cancer patient using a rectal balloon

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    Jung, Hae Youn; Seok, Jin Yong; Hong, Joo Wan; Chang, Nam Jun; Choi, Byeong Don; Park, Jin Hong [Dept. of Radiation Oncology, Seoul National University Bundang Hospital, Sangnam (Korea, Republic of)

    2015-06-15

    The dose distribution of organ at risk (OAR) and normal tissue is affected by treatment technique in postoperative radiation therapy for prostate cancer. The aim of this study was to compare dose distribution characteristic and to evaluate treatment efficiency by devising VMAT plans according to applying differed number of arc and IMRT plan for postoperative patient of prostate cancer radiation therapy using a rectal balloon. Ten patients who received postoperative prostate radiation therapy in our hospital were compared. CT images of patients who inserted rectal balloon were acquired with 3 mm thickness and 10 MV energy of HD120MLC equipped Truebeam STx (Varian, Palo Alto, USA) was applied by using Eclipse (Version 11.0, Varian, Palo Alto, USA). 1 Arc, 2 Arc VMAT plans and 7-field IMRT plan were devised for each patient and same values were applied for dose volume constraint and plan normalization. To evaluate these plans, PTV coverage, conformity index (CI) and homogeneity index (HI) were compared and R{sub 50%} was calculated to assess low dose spillage as per treatment plan. D{sub 50%} of rectum and bladder Dmean were compared on OAR. And to evaluate the treatment efficiency, total monitor units(MU) and delivery time were considered. Each assessed result was analyzed by average value of 10 patients. Additionally, portal dosimetry was carried out for accuracy verification of beam delivery. There was no significant difference on PTV coverage and HI among 3 plans. Especially CI and R{sub 50%} on 7F-IMRT were the highest as 1.230, 3.991 respectively(p=0.00). Rectum D{sub 50%} was similar between 1A-VMAT and 2A-VMAT. But approximately 7% higher value was observed on 7F-IMRT compare to the others(p=0.02) and bladder Dmean were similar among the all plan(P>0.05). Total MU were 494.7, 479.7, 757.9 respectively(P=0.00) for 1A-VMAT, 2A-VMAT, 7F-IMRT and at the most on 7F-IMRT. The delivery time were 65.2sec, 133.1sec, 145.5sec respectively(p=0.00). The obvious shortest

  11. Planning analysis for locally advanced lung cancer: dosimetric and efficiency comparisons between intensity-modulated radiotherapy (IMRT, single-arc/partial-arc volumetric modulated arc therapy (SA/PA-VMAT

    Directory of Open Access Journals (Sweden)

    Zhou Xiaojuan

    2011-10-01

    Full Text Available Abstract Purpose To analyze the differences between the intensity-modulated radiotherapy (IMRT, single/partial-arc volumetric modulated arc therapy (SA/PA-VMAT techniques in treatment planning for locally advanced lung cancer. Materials and methods 12 patients were retrospectively studied. In each patient's case, several parameters were analyzed based on the dose-volume histograms (DVH of the IMRT, SA/PA-VMAT plans respectively. Also, each plan was delivered to a phantom for time comparison. Results The SA-VMAT plans showed the superior target dose coverage, although the minimum/mean/maximum doses to the target were similar. For the total and contralateral lungs, the higher V5/10, lower V20/30 and mean lung dose (MLD were observed in the SA/PA-VMAT plans (p 20, V30 and MLD of the controlateral lung more notably, comparing to those parameters of the IMRT and SA-VMAT plans respectively. The delivered monitor units (MUs and treatment times were reduced significantly with VMAT plans, especially PA-VMAT plans (for MUs: mean 458.3 vs. 439.2 vs. 435.7 MUs, p vs. 10.6 vs. 6.4 minutes, p Conclusions The SA-VMAT technique achieves highly conformal dose distribution to the target. Comparing to the IMRT plans, the higher V5/10, lower V20/30 and MLD were observed in the total and contralateral lungs in the VMAT plans, especially in the PA-VMAT plans. The SA/PA-VMAT plans also reduced treatment time with more efficient dose delivering. But the clinical benefit of the VMAT technique for locally advanced lung cancer needs further investigations.

  12. SU-E-P-51: Dosimetric Comparison to Organs at Risk Sparing Using Volumetric-Modulated Arc Therapy Versus Intensity-Modulated Radiotherapy in Postoperative Radiotherapy of Left-Sided Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, L; Deng, G [Department of Oncology, Shandong University School of Medicine, Jinan, Shandong (China); Xie, J; Cheng, J; Liang, N; Zhang, J [Department of Radiation Oncology, Qianfoshan Hospital Affiliated to Shandon, Jinan, Shandong (China); Zhang, J; Luo, H [Division of Oncology, Department of Graduate, Weifang Medical College, 2610, Jinan, Shandong (China)

    2015-06-15

    Purpose: To compare the dosimetric characteristics of volumetric-modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) techniques in treatment planning for left-sided breast cancer patients with modified radical mastectomy. Methods: Twenty-four left-sided breast cancer patients treated with modified radical mastectomy were selected in this study. The planning target volume (PTV) was generated by using 7-mm uniform expansion of the clinical target volume (CTV) in all direction except the skin surface. The organs at risk (OARs) included heart, left lung, right lung, and right breast. Dose volume histograms (DVHs) were utilized to evaluate the dose distribution in PTV and OARs. Results: Both VMAT and IMRT plans met the requirement of PTV coverage. VMAT was superior to IMRT in terms of conformity, with a statistically significant difference (p=0.024). Mean doses, V5 and V10 of heart and both lungs in VMAT plans were significantly decreased compared to IMRT plans (P<0.05), but in terms of heart volume irradiated by high doses (V30 and V45), no significant differences were observed (P>0.05). For right breast, VMAT showed the reduction of V5 in comparison with IMRT (P<0.05). Additionally, the mean number of monitor units (MU) and treatment time in VMAT (357.21, 3.62 min) were significantly less than those in IMRT (1132.85, 8.74 min). Conclusion: VMAT showed similar PTV coverage and significant advantage in OARs sparing compared with IMRT, especially in terms of decreased volumes irradiated by low doses, while significantly reducing the treatment time and MU number.

  13. SU-E-T-810: Volumetric Modulated Arc Therapy and Conventional Intensity-Modulated Radiotherapy for Non-Small-Cell Lung Cancer with Simultaneously Integrated Boost Radiation Therapy: A Planning Comparison Study

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    Liu, T; Chen, J; Zhang, G; Sun, T [Shandong Tumor Hospital, Jinan, Shandong (China)

    2015-06-15

    Purpose: To compare and analyze the characteristics of intensity-modulated arc therapy(IMAT) versus fixed-gantry intensity-modulated radiotherapy(IMRT) in treatment of non-small-cell lung cancer. Methods: Twelve patients treated in our radiotherapy center were selected for this study. The patient subsequently underwent 4D-CT simulation.Margins of 5mm and 10mm were added to the ITV to generate the CTV and PTV respectively. Three treatment plans (IMRT,one single arc (RA1),double arcs (RA2))were generated with Eclipse ver.8.6 planning systems. Using a dose level of 75Gy in 15fractions to the ITV,60Gy in 15fractions to the CTV and 45Gy in 15fractions to the PTV respectively. The target and normol tissue volumes were compared,as were the dosimetry parameters. Results: There were no significant differences in CI of ITV,PTV,HI of ITV,CTV and PTV, V5,V10,V15,V20,V25,V30,V45,V50 of total-lung and mean lung dose (all p>0.05). However, the differences were significant in terms of CI of CTV,V5 of B-P (all p<0.05). On the MU, IMRT=1540MU,RA1=1006 MU and RA2=1096 MU. (F=12.00,P=0.000).On the treatment time, IMRT= 13.5min,RA1= 1.5min,and RA2=2.5 min (F= 30.11,P=0.000 ). Conclusion: IMAT is equal to IMRT in dosimetril evaluation. Due to much less Mu and delivery time,IMAT is an ideal technique in treating patients by reduceing the uncomfortable influnce which could effect the treatment.

  14. Late Toxicity After Intensity-Modulated Radiation Therapy for Localized Prostate Cancer: An Exploration of Dose-Volume Histogram Parameters to Limit Genitourinary and Gastrointestinal Toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Pederson, Aaron W.; Fricano, Janine; Correa, David; Pelizzari, Charles A. [Department of Radiation and Cellular Oncology, Pritzker School of Medicine, University of Chicago, Chicago, IL (United States); Liauw, Stanley L., E-mail: sliauw@radonc.uchicago.edu [Department of Radiation and Cellular Oncology, Pritzker School of Medicine, University of Chicago, Chicago, IL (United States)

    2012-01-01

    Purpose: To characterize the late genitourinary (GU) and gastrointestinal (GI) toxicity for prostate cancer patients treated with intensity-modulated radiation therapy (IMRT) and propose dose-volume histogram (DVH) guidelines to limit late treatment-related toxicity. Methods and Materials: In this study 296 consecutive men were treated with IMRT for adenocarcinoma of the prostate. Most patients received treatment to the prostate with or without proximal seminal vesicles (90%), to a median dose of 76 Gy. Concurrent androgen deprivation therapy was given to 150 men (51%) for a median of 4 months. Late toxicity was defined by Common Toxicity Criteria version 3.0 as greater than 3 months after radiation therapy completion. Four groupings of DVH parameters were defined, based on the percentage of rectal or bladder tissue receiving 70 Gy (V{sub 70}), 65 Gy (V{sub 65}), and 40 Gy (V{sub 40}). These DVH groupings, as well as clinical and treatment characteristics, were correlated to maximal Grade 2+ GU and GI toxicity. Results: With a median follow-up of 41 months, the 4-year freedom from maximal Grade 2+ late toxicity was 81% and 91% for GU and GI systems, respectively, and by last follow-up, the rates of Grade 2+ GU and GI toxicity were 9% and 5%, respectively. On multivariate analysis, whole-pelvic IMRT was associated with Grade 2+ GU toxicity and age was associated with Grade 2+ GI toxicity. Freedom from Grade 2+ GI toxicity at 4 years was 100% for men with rectal V{sub 70} {<=}10%, V{sub 65} {<=}20%, and V{sub 40} {<=}40%; 92% for men with rectal V{sub 70} {<=}20%, V{sub 65} {<=}40%, and V{sub 40} {<=}80%; and 85% for men exceeding these criteria (p = 0.13). These criteria were more highly associated with GI toxicity in men aged {>=}70 years (p = 0.07). No bladder dose-volume relationships were associated with the risk of GU toxicity. Conclusions: IMRT is associated with low rates of severe GU or GI toxicity after treatment for prostate cancer. Rectal dose constraints

  15. SU-E-T-452: Impact of Respiratory Motion On Robustly-Optimized Intensity-Modulated Proton Therapy to Treat Lung Cancers

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W; Schild, S; Bues, M [Mayo Clinic Arizona, Phoenix, AZ (United States); Liao, Z; Sahoo, N [MD Anderson Cancer Center, Houston, TX (United States); Park, P [Scottsdale, GA (United States); Li, H [M.D. Anderson Cancer Center, Houston, TX (United States); Li, Y [Varian Medical Systems, Houston, TX (United States); Li, X; Shen, J [Mayo Clinic Arizona, Phoenix, AA (United States); Anand, A [Mayo Clinic Arizona, Phoenix (United States); Dong, L [Scripps Proton Therapy Center, San Diego, CA (United States); Zhu, X; Mohan, R [UT MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-01

    Purpose: We compared conventionally optimized intensity-modulated proton therapy (IMPT) treatment plans against the worst-case robustly optimized treatment plans for lung cancer. The comparison of the two IMPT optimization strategies focused on the resulting plans' ability to retain dose objectives under the influence of patient set-up, inherent proton range uncertainty, and dose perturbation caused by respiratory motion. Methods: For each of the 9 lung cancer cases two treatment plans were created accounting for treatment uncertainties in two different ways: the first used the conventional Method: delivery of prescribed dose to the planning target volume (PTV) that is geometrically expanded from the internal target volume (ITV). The second employed the worst-case robust optimization scheme that addressed set-up and range uncertainties through beamlet optimization. The plan optimality and plan robustness were calculated and compared. Furthermore, the effects on dose distributions of the changes in patient anatomy due to respiratory motion was investigated for both strategies by comparing the corresponding plan evaluation metrics at the end-inspiration and end-expiration phase and absolute differences between these phases. The mean plan evaluation metrics of the two groups were compared using two-sided paired t-tests. Results: Without respiratory motion considered, we affirmed that worst-case robust optimization is superior to PTV-based conventional optimization in terms of plan robustness and optimality. With respiratory motion considered, robust optimization still leads to more robust dose distributions to respiratory motion for targets and comparable or even better plan optimality [D95% ITV: 96.6% versus 96.1% (p=0.26), D5% - D95% ITV: 10.0% versus 12.3% (p=0.082), D1% spinal cord: 31.8% versus 36.5% (p =0.035)]. Conclusion: Worst-case robust optimization led to superior solutions for lung IMPT. Despite of the fact that robust optimization did not explicitly

  16. Safety and efficacy of semiextended field intensity-modulated radiation therapy and concurrent cisplatin in locally advanced cervical cancer patients: An observational study of 10-year experience.

    Science.gov (United States)

    Lee, Jie; Lin, Jhen-Bin; Sun, Fang-Ju; Chen, Yu-Jen; Chang, Chih-Long; Jan, Ya-Ting; Wu, Meng-Hao

    2017-03-01

    Patients with locally advanced cervical cancer (LACC) are at risk of para-aortic lymph node (PALN) metastasis. Pelvic concurrent chemoradiotherapy, the current standard treatment for LACC, has a PALN failure rate of 9% according to the Radiation Therapy Oncology Group Trial 90-01, suggesting that it may not completely eliminate all microscopic tumors in the PALNs. To minimize the toxicities associated with conventional prophylactic extended-field radiotherapy, our institute use prophylactic semiextended field radiotherapy that includes only the PALNs below the level of the renal vessels. Use of intensity-modulated radiotherapy (IMRT) is another means of reducing the incidence of toxicity. This study evaluated the safety and efficacy of prophylactic semiextended field IMRT (SEF-IMRT) and concurrent cisplatin chemotherapy in patients with LACC.We retrospectively assessed survival and toxicity in 76 patients with stage IB2-IVA cervical cancer and negative PALNs who received prophylactic SEF-IMRT and concurrent weekly cisplatin (40 mg/m) between 2004 and 2013. The region targeted by SEF-IMRT included the PALNs below the level of the renal vessels, and the prescribed dose was 50.4 Gy in 28 fractions. Brachytherapy was administered at a dose of 30 Gy in 6 fractions. Survival outcomes were calculated by using the Kaplan-Meier method, and acute and late toxicities were scored according to the Common Terminology Criteria for Adverse Events, version 3.0.All patients completed the planned SEF-IMRT, as well as brachytherapy. Acute grade ≥3 gastrointestinal, genitourinary, and hematologic toxicities were observed in 2, 0, and 41 patients, respectively. The median follow-up time after SEF-IMRT was 55 (range, 11-124) months. Eight patients developed out-field distant recurrences without PALN failure, and 1 patient experienced out-field PALN failure with simultaneous distant metastasis. No patients had late genitourinary toxicities, and 3 patients had late grade 3

  17. Single Vocal Cord Irradiation: Image Guided Intensity Modulated Hypofractionated Radiation Therapy for T1a Glottic Cancer: Early Clinical Results

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    Al-Mamgani, Abrahim, E-mail: a.almamgani@nki.nl [Department of Radiation Oncology – Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam (Netherlands); Kwa, Stefan L.S.; Tans, Lisa; Moring, Michael; Fransen, Dennie; Mehilal, Robert; Verduijn, Gerda M. [Department of Radiation Oncology – Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam (Netherlands); Baatenburg de Jong, Rob J. [Department of Otolaryngology and Head and Neck Surgery – Erasmus MC, University Medical Center Rotterdam, Rotterdam (Netherlands); Heijmen, Ben J.M.; Levendag, Peter C. [Department of Radiation Oncology – Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam (Netherlands)

    2015-10-01

    Purpose: To report, from a retrospective analysis of prospectively collected data, on the feasibility, outcome, toxicity, and voice-handicap index (VHI) of patients with T1a glottic cancer treated by a novel intensity modulated radiation therapy technique developed at our institution to treat only the involved vocal cord: single vocal cord irradiation (SVCI). Methods and Materials: Thirty patients with T1a glottic cancer were treated by means of SVCI. Dose prescription was set to 16 × 3.63 Gy (total dose 58.08 Gy). The clinical target volume was the entire vocal cord. Setup verification was done by means of an online correction protocol using cone beam computed tomography. Data for voice quality assessment were collected prospectively at baseline, end of treatment, and 4, 6, and 12 weeks and 6, 12, and 18 months after treatment using VHI questionnaires. Results: After a median follow-up of 30 months (range, 7-50 months), the 2-year local control and overall survival rates were 100% and 90% because no single local recurrence was reported and 3 patients died because of comorbidity. All patients have completed the intended treatment schedule; no treatment interruptions and no grade 3 acute toxicity were reported. Grade 2 acute dermatitis or dysphagia was reported in only 5 patients (17%). No serious late toxicity was reported; only 1 patient developed temporary grade 2 laryngeal edema, and responded to a short-course of corticosteroid. The VHI improved significantly, from 33.5 at baseline to 9.5 and 10 at 6 weeks and 18 months, respectively (P<.001). The control group, treated to the whole larynx, had comparable local control rates (92.2% vs 100%, P=.24) but more acute toxicity (66% vs 17%, P<.0001) and higher VHI scores (23.8 and 16.7 at 6 weeks and 18 months, respectively, P<.0001). Conclusion: Single vocal cord irradiation is feasible and resulted in maximal local control rate at 2 years. The deterioration in VHI scores was slight and temporary and

  18. Dose-Escalated Intensity-Modulated Radiotherapy Is Feasible and May Improve Locoregional Control and Laryngeal Preservation in Laryngo-Hypopharyngeal Cancers

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    Miah, Aisha B.; Bhide, Shreerang A.; Guerrero-Urbano, M. Teresa [Head and Neck Unit, The Royal Marsden National Health Service (NHS) Foundation Trust, London (United Kingdom); Institute of Cancer Research, London (United Kingdom); Clark, Catharine; Bidmead, A. Margaret [Institute of Cancer Research, London (United Kingdom); Department of Physics, The Royal Marsden NHS Foundation Trust, London (United Kingdom); St Rose, Suzanne; Barbachano, Yolanda; A' Hern, Roger [Department of Statistics, The Royal Marsden NHS Foundation Trust, London (United Kingdom); Tanay, Mary; Hickey, Jennifer; Nicol, Robyn; Newbold, Kate L. [Head and Neck Unit, The Royal Marsden National Health Service (NHS) Foundation Trust, London (United Kingdom); Harrington, Kevin J. [Head and Neck Unit, The Royal Marsden National Health Service (NHS) Foundation Trust, London (United Kingdom); Institute of Cancer Research, London (United Kingdom); Nutting, Christopher M., E-mail: chris.nutting@rmh.nhs.uk [Head and Neck Unit, The Royal Marsden National Health Service (NHS) Foundation Trust, London (United Kingdom); Institute of Cancer Research, London (United Kingdom)

    2012-02-01

    Purpose: To determine the safety and outcomes of induction chemotherapy followed by dose-escalated intensity-modulated radiotherapy (IMRT) with concomitant chemotherapy in locally advanced squamous cell cancer of the larynx and hypopharynx (LA-SCCL/H). Methods and Materials: A sequential cohort Phase I/II trial design was used to evaluate moderate acceleration and dose escalation. Patients with LA-SCCL/H received IMRT at two dose levels (DL): DL1, 63 Gy/28 fractions (Fx) to planning target volume 1 (PTV1) and 51.8 Gy/28 Fx to PTV2; DL2, 67.2 Gy/28 Fx and 56 Gy/28 Fx to PTV1 and PTV2, respectively. Patients received induction cisplatin/5-fluorouracil and concomitant cisplatin. Acute and late toxicities and tumor control rates were recorded. Results: Between September 2002 and January 2008, 60 patients (29 DL1, 31 DL2) with Stage III (41% DL1, 52% DL2) and Stage IV (52% DL1, 48% DL2) disease were recruited. Median (range) follow-up for DL1 was 51.2 (12.1-77.3) months and for DL2 was 36.2 (4.2-63.3) months. Acute Grade 3 (G3) dysphagia was higher in DL2 (87% DL2 vs. 59% DL1), but other toxicities were equivalent. One patient in DL1 required dilatation of a pharyngeal stricture (G3 dysphagia). In DL2, 2 patients developed benign pharyngeal strictures at 1 year. One underwent a laryngo-pharyngectomy and the other a dilatation. No other G3/G4 toxicities were reported. Overall complete response was 79% (DL1) and 84% (DL2). Two-year locoregional progression-free survival rates were 64.2% (95% confidence interval, 43.5-78.9%) in DL1 and 78.4% (58.1-89.7%) in DL2. Two-year laryngeal preservation rates were 88.7% (68.5-96.3%) in DL1 and 96.4% (77.7-99.5%) in DL2. Conclusions: At a mean follow-up of 36 months, dose-escalated chemotherapy-IMRT at DL2 has so far been safe to deliver. In this study, DL2 delivered high rates of locoregional control, progression-free survival, and organ preservation and has been selected as the experimental arm in a Cancer Research UK Phase III

  19. Dosimetric comparison of intensity modulated radiotherapy isocentric field plans and field in field (FIF) forward plans in the treatment of breast cancer.

    Science.gov (United States)

    Al-Rahbi, Zakiya Salem; Al Mandhari, Zahid; Ravichandran, Ramamoorthy; Al-Kindi, Fatma; Davis, Cheriyathmanjiyil Anthony; Bhasi, Saju; Satyapal, Namrata; Rajan, Balakrishnan

    2013-01-01

    The present study is aimed at comparing the planning and delivery efficiency between three-dimensional conformal radiotherapy (3D-CRT), field-in-field, forward planned, intensity modulated radiotherapy (FIF-FP-IMRT), and inverse planned intensity modulated radiotherapy (IP-IMRT). Treatment plans of 20 patients with left-sided breast cancer, 10 post-mastectomy treated to a prescribed dose of 45 Gy to the chest wall in 20 fractions, and 10 post-breast-conserving surgery to a prescribed dose of 50 Gy to the whole breast in 25 fractions, with 3D-CRT were selected. The FiF-FP-IMRT plans were created by combining two open fields with three to four segments in two tangential beam directions. Eight different beam directions were chosen to create IP-IMRT plans and were inversely optimized. The homogeneity of dose to planning target volume (PTV) and the dose delivered to heart and contralateral breast were compared among the techniques in all the 20 patients. All the three radiotherapy techniques achieved comparable radiation dose delivery to PTV-95% of the prescribed dose covering > 95% of the breast PTV. The mean volume of PTV receiving 105% (V105) of the prescribed dose was 1.7% (range 0-6.8%) for IP-IMRT, 1.9% for FP-IMRT, and 3.7% for 3D-CRT. The homogeneity and conformity indices (HI and CI) were similar for 3D-CRT and FP-IMRT, whereas the IP-IMRT plans had better conformity index at the cost of less homogeneity. The 3D-CRT and FiF-FP-IMRT plans achieved similar sparing of critical organs. The low-dose volumes (V5Gy) in the heart and lungs were larger in IP-IMRT than in the other techniques. The value of the mean dose to the ipsilateral lung was higher for IP-IMRT than the values for with FiF-FP-IMRT and 3D-CRT. In the current study, the relative volume of contralateral breast receiving low doses (0.01, 0.6, 1, and 2Gy) was significantly lower for the FiF-FP-IMRT and 3D-CRT plans than for the IP-IMRT plan. Compared with 3D-CRT and IP-IMRT, FiF-FP-IMRT proved to be a

  20. Fan-beam intensity modulated proton therapy

    Science.gov (United States)

    Hill, Patrick; Westerly, David; Mackie, Thomas

    2013-01-01

    Purpose: This paper presents a concept for a proton therapy system capable of delivering intensity modulated proton therapy using a fan beam of protons. This system would allow present and future gantry-based facilities to deliver state-of-the-art proton therapy with the greater normal tissue sparing made possible by intensity modulation techniques. Methods: A method for producing a divergent fan beam of protons using a pair of electromagnetic quadrupoles is described and particle transport through the quadrupole doublet is simulated using a commercially available software package. To manipulate the fan beam of protons, a modulation device is developed. This modulator inserts or retracts acrylic leaves of varying thickness from subsections of the fan beam. Each subsection, or beam channel, creates what effectively becomes a beam spot within the fan area. Each channel is able to provide 0–255 mm of range shift for its associated beam spot, or stop the beam and act as an intensity modulator. Results of particle transport simulations through the quadrupole system are incorporated into the MCNPX Monte Carlo transport code along with a model of the range and intensity modulation device. Several design parameters were investigated and optimized, culminating in the ability to create topotherapy treatment plans using distal-edge tracking on both phantom and patient datasets. Results: Beam transport calculations show that a pair of electromagnetic quadrupoles can be used to create a divergent fan beam of 200 MeV protons over a distance of 2.1 m. The quadrupole lengths were 30 and 48 cm, respectively, with transverse field gradients less than 20 T/m, which is within the range of water-cooled magnets for the quadrupole radii used. MCNPX simulations of topotherapy treatment plans suggest that, when using the distal edge tracking delivery method, many delivery angles are more important than insisting on narrow beam channel widths in order to obtain conformal target coverage

  1. SU-E-T-338: Dosimetric Study of Volumetric Modulated Arc Therapy (VMAT) and Intensity Modulated Radiation Therapy (IMRT) for Stereotactic Body Radiation Therapy (SBRT) in Early Stage Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I; Quinn, K; Seebach, A; Wang, H [OSF Saint Anthony Medical Center, Rockford, IL (United States); Yah, R [University of Illinois College of Medicine at Rockford, Rockford, IL (United States)

    2015-06-15

    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 for 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.

  2. Incidence of Secondary Cancer Development After High-Dose Intensity-Modulated Radiotherapy and Image-Guided Brachytherapy for the Treatment of Localized Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Zelefsky, Michael J., E-mail: Zelefskm@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Housman, Douglas M.; Pei Xin; Alicikus, Zumre; Magsanoc, Juan Martin [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Dauer, Lawrence T.; St Germain, Jean [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Yamada, Yoshiya; Kollmeier, Marisa; Cox, Brett [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Zhang Zhigang [Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2012-07-01

    Purpose: To report the incidence and excess risk of second malignancy (SM) development compared with the general population after external beam radiotherapy (EBRT) and brachytherapy to treat prostate cancer. Methods and Materials: Between 1998 and 2001, 1,310 patients with localized prostate cancer were treated with EBRT (n = 897) or brachytherapy (n = 413). We compared the incidence of SMs in our patients with that of the general population extracted from the National Cancer Institute's Surveillance, Epidemiology, and End Results data set combined with the 2000 census data. Results: The 10-year likelihood of SM development was 25% after EBRT and 15% after brachytherapy (p = .02). The corresponding 10-year likelihood for in-field SM development in these groups was 4.9% and 1.6% (p = .24). Multivariate analysis showed that EBRT vs. brachytherapy and older age were the only significant predictors for the development of all SMs (p = .037 and p = .030), with a trend for older patients to develop a SM. The increased incidence of SM for EBRT patients was explained by the greater incidence of skin cancer outside the radiation field compared with that after brachytherapy (10.6% and 3.3%, respectively, p = .004). For the EBRT group, the 5- and 10-year mortality rate was 1.96% and 5.1% from out-of field cancer, respectively; for in-field SM, the corresponding mortality rates were 0.1% and 0.7%. Among the brachytherapy group, the 5- and 10-year mortality rate related to out-of field SM was 0.8% and 2.7%, respectively. Our observed SM rates after prostate RT were not significantly different from the cancer incidence rates in the general population. Conclusions: Using modern sophisticated treatment techniques, we report low rates of in-field bladder and rectal SM risks after prostate cancer RT. Furthermore, the likelihood of mortality secondary to a SM was unusual. The greater rate of SM observed with EBRT vs. brachytherapy was related to a small, but significantly

  3. Acute Toxicity After Image-Guided Intensity Modulated Radiation Therapy Compared to 3D Conformal Radiation Therapy in Prostate Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Wortel, Ruud C.; Incrocci, Luca [Department of Radiation Oncology, Erasmus Medical Center Cancer Institute, Rotterdam (Netherlands); Pos, Floris J.; Lebesque, Joos V.; Witte, Marnix G.; Heide, Uulke A. van der; Herk, Marcel van [Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam (Netherlands); Heemsbergen, Wilma D., E-mail: w.heemsbergen@nki.nl [Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam (Netherlands)

    2015-03-15

    Purpose: Image-guided intensity modulated radiation therapy (IG-IMRT) allows significant dose reductions to organs at risk in prostate cancer patients. However, clinical data identifying the benefits of IG-IMRT in daily practice are scarce. The purpose of this study was to compare dose distributions to organs at risk and acute gastrointestinal (GI) and genitourinary (GU) toxicity levels of patients treated to 78 Gy with either IG-IMRT or 3D-CRT. Methods and Materials: Patients treated with 3D-CRT (n=215) and IG-IMRT (n=260) receiving 78 Gy in 39 fractions within 2 randomized trials were selected. Dose surface histograms of anorectum, anal canal, and bladder were calculated. Identical toxicity questionnaires were distributed at baseline, prior to fraction 20 and 30 and at 90 days after treatment. Radiation Therapy Oncology Group (RTOG) grade ≥1, ≥2, and ≥3 endpoints were derived directly from questionnaires. Univariate and multivariate binary logistic regression analyses were applied. Results: The median volumes receiving 5 to 75 Gy were significantly lower (all P<.001) with IG-IMRT for anorectum, anal canal, and bladder. The mean dose to the anorectum was 34.4 Gy versus 47.3 Gy (P<.001), 23.6 Gy versus 44.6 Gy for the anal canal (P<.001), and 33.1 Gy versus 43.2 Gy for the bladder (P<.001). Significantly lower grade ≥2 toxicity was observed for proctitis, stool frequency ≥6/day, and urinary frequency ≥12/day. IG-IMRT resulted in significantly lower overall RTOG grade ≥2 GI toxicity (29% vs 49%, respectively, P=.002) and overall GU grade ≥2 toxicity (38% vs 48%, respectively, P=.009). Conclusions: A clinically meaningful reduction in dose to organs at risk and acute toxicity levels was observed in IG-IMRT patients, as a result of improved technique and tighter margins. Therefore reduced late toxicity levels can be expected as well; additional research is needed to quantify such reductions.

  4. A Multi-institutional Clinical Trial of Rectal Dose Reduction via Injected Polyethylene-Glycol Hydrogel During Intensity Modulated Radiation Therapy for Prostate Cancer: Analysis of Dosimetric Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Song, Danny Y., E-mail: dsong2@jhmi.edu [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland (United States); Herfarth, Klaus K.; Uhl, Matthias [Department of Radiation Oncology, University of Heidelberg, Heidelberg (Germany); Eble, Michael J.; Pinkawa, Michael [Department of Radiation Oncology, RWTH Aachen University, Aachen (Germany); Triest, Baukelien van; Kalisvaart, Robin [Department of Radiation Oncology, Netherlands Cancer Institute/Antoni van Leeuwenhoek Ziekenhuis, Amsterdam (Netherlands); Weber, Damien C.; Miralbell, Raymond [Department of Radiation Oncology, Geneva University, Geneva (Switzerland); DeWeese, Theodore L. [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland (United States); Ford, Eric C. [Department of Radiation Oncology, University of Washington, Seattle, Washington (United States)

    2013-09-01

    Purpose: To characterize the effect of a prostate-rectum spacer on dose to rectum during external beam radiation therapy for prostate cancer and to assess for factors correlated with rectal dose reduction. Methods and Materials: Fifty-two patients at 4 institutions were enrolled into a prospective pilot clinical trial. Patients underwent baseline scans and then were injected with perirectal spacing hydrogel and rescanned. Intensity modulated radiation therapy plans were created on both scans for comparison. The objectives were to establish rates of creation of ≥7.5 mm of prostate-rectal separation, and decrease in rectal V70 of ≥25%. Multiple regression analysis was performed to evaluate the associations between preinjection and postinjection changes in rectal V70 and changes in plan conformity, rectal volume, bladder volume, bladder V70, planning target volume (PTV), and postinjection midgland separation, gel volume, gel thickness, length of PTV/gel contact, and gel left-to-right symmetry. Results: Hydrogel resulted in ≥7.5-mm prostate-rectal separation in 95.8% of patients; 95.7% had decreased rectal V70 of ≥25%, with a mean reduction of 8.0 Gy. There were no significant differences in preinjection and postinjection prostate, PTV, rectal, and bladder volumes. Plan conformities were significantly different before versus after injection (P=.02); plans with worse conformity indexes after injection compared with before injection (n=13) still had improvements in rectal V70. In multiple regression analysis, greater postinjection reduction in V70 was associated with decreased relative postinjection plan conformity (P=.01). Reductions in V70 did not significantly vary by institution, despite significant interinstitutional variations in plan conformity. There were no significant relationships between reduction in V70 and the other characteristics analyzed. Conclusions: Injection of hydrogel into the prostate-rectal interface resulted in dose reductions to rectum

  5. The dosimetric impact of daily setup error on target volumes and surrounding normal tissue in the treatment of prostate cancer with intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Algan, Ozer, E-mail: oalgan@ouhsc.edu [Department of Radiation Oncology, Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States); Jamgade, Ambarish; Ali, Imad; Christie, Alana; Thompson, J. Spencer; Thompson, David; Ahmad, Salahuddin; Herman, Terence [Department of Radiation Oncology, Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States)

    2012-01-01

    The purpose of this study was to evaluate the impact of daily setup error and interfraction organ motion on the overall dosimetric radiation treatment plans. Twelve patients undergoing definitive intensity-modulated radiation therapy (IMRT) treatments for prostate cancer were evaluated in this institutional review board-approved study. Each patient had fiducial markers placed into the prostate gland before treatment planning computed tomography scan. IMRT plans were generated using the Eclipse treatment planning system. Each patient was treated to a dose of 8100 cGy given in 45 fractions. In this study, we retrospectively created a plan for each treatment day that had a shift available. To calculate the dose, the patient would have received under this plan, we mathematically 'negated' the shift by moving the isocenter in the exact opposite direction of the shift. The individualized daily plans were combined to generate an overall plan sum. The dose distributions from these plans were compared with the treatment plans that were used to treat the patients. Three-hundred ninety daily shifts were negated and their corresponding plans evaluated. The mean isocenter shift based on the location of the fiducial markers was 3.3 {+-} 6.5 mm to the right, 1.6 {+-} 5.1 mm posteriorly, and 1.0 {+-} 5.0 mm along the caudal direction. The mean D95 doses for the prostate gland when setup error was corrected and uncorrected were 8228 and 7844 cGy (p < 0.002), respectively, and for the planning target volume (PTV8100) was 8089 and 7303 cGy (p < 0.001), respectively. The mean V95 values when patient setup was corrected and uncorrected were 99.9% and 87.3%, respectively, for the PTV8100 volume (p < 0.0001). At an individual patient level, the difference in the D95 value for the prostate volume could be >1200 cGy and for the PTV8100 could approach almost 2000 cGy when comparing corrected against uncorrected plans. There was no statistically significant difference in the D35

  6. The dosimetric impact of daily setup error on target volumes and surrounding normal tissue in the treatment of prostate cancer with intensity-modulated radiation therapy.

    Science.gov (United States)

    Algan, Ozer; Jamgade, Ambarish; Ali, Imad; Christie, Alana; Thompson, J Spencer; Thompson, David; Ahmad, Salahuddin; Herman, Terence

    2012-01-01

    The purpose of this study was to evaluate the impact of daily setup error and interfraction organ motion on the overall dosimetric radiation treatment plans. Twelve patients undergoing definitive intensity-modulated radiation therapy (IMRT) treatments for prostate cancer were evaluated in this institutional review board-approved study. Each patient had fiducial markers placed into the prostate gland before treatment planning computed tomography scan. IMRT plans were generated using the Eclipse treatment planning system. Each patient was treated to a dose of 8100 cGy given in 45 fractions. In this study, we retrospectively created a plan for each treatment day that had a shift available. To calculate the dose, the patient would have received under this plan, we mathematically "negated" the shift by moving the isocenter in the exact opposite direction of the shift. The individualized daily plans were combined to generate an overall plan sum. The dose distributions from these plans were compared with the treatment plans that were used to treat the patients. Three-hundred ninety daily shifts were negated and their corresponding plans evaluated. The mean isocenter shift based on the location of the fiducial markers was 3.3 ± 6.5 mm to the right, 1.6 ± 5.1 mm posteriorly, and 1.0 ± 5.0 mm along the caudal direction. The mean D95 doses for the prostate gland when setup error was corrected and uncorrected were 8228 and 7844 cGy (p 1200 cGy and for the PTV8100 could approach almost 2000 cGy when comparing corrected against uncorrected plans. There was no statistically significant difference in the D35 parameter for the surrounding normal tissue except for the dose received by the penile bulb and the right hip. Our dosimetric evaluation suggests significant underdosing with inaccurate target localization and emphasizes the importance of accurate patient setup and target localization. Further studies are needed to evaluate the impact of intrafraction organ motion, rotation

  7. Long-Term Quality of Life After Swallowing and Salivary-Sparing Chemo–Intensity Modulated Radiation Therapy in Survivors of Human Papillomavirus–Related Oropharyngeal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Vainshtein, Jeffrey M. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Moon, Dominic H. [University of Michigan Medical School, Ann Arbor, Michigan (United States); Feng, Felix Y. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Chepeha, Douglas B. [Department of Otolaryngology—Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan (United States); Eisbruch, Avraham, E-mail: eisbruch@umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Stenmark, Matthew H. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)

    2015-04-01

    Purpose: To evaluate long-term health-related quality of life (HRQOL) in 2 prospective studies of chemo–intensity modulated radiation therapy (chemo-IMRT) for oropharyngeal cancer (OPC). Methods and Materials: Of 93 patients with stage III/IV OPC treated on prospective studies of swallowing and salivary organ-sparing chemo-IMRT, 69 were eligible for long-term HRQOL assessment. Three validated patient-reported instruments, the Head and Neck QOL (HNQOL) questionnaire, the University of Washington quality of life (UWQOL) questionnaire, and the Xerostomia Questionnaire (XQ), previously administered from baseline through 2 years in the parent studies, were readministered at long-term follow-up, along with the Short-Form 36. Long-term changes in HRQOL from before treatment and 2 years were evaluated. Results: Forty patients (58%) with a median follow-up of 6.5 years participated, 39 of whom (97.5%) had confirmed human papillomavirus–positive OPC. Long term, no clinically significant worsening was detected in mean HRQOL scores compared with 2 years, with stable or improved HRQOL from before treatment in nearly all domains. “Moderate” or greater severity problems were uncommon, reported by 5% of patients for eating, 5% for swallowing, and 2.5% and 5% by HNQOL and UWQOL summary scores, respectively. Freedom from percutaneous endoscopic gastrostomy tube dependence and stricture dilation beyond 2 years was 97.5% and 95%, respectively. Eleven percent and 14% of patients reported “moderate” or “severe” long-term worsening in HNQOL Pain and Overall Bother domains, respectively, which were associated with mean dose to the cervical esophagus, larynx, and pharyngeal constrictors. Conclusions: At more than 6 years' median follow-up, OPC patients treated with swallowing and salivary organ-sparing chemo-IMRT reported stable or improved HRQOL in nearly all domains compared with both before treatment and 2-year follow-up. New late toxicity after 2 years was

  8. Dosimetric study of RapidArc plans and conventional intensity modulated radiotherapy for prostate cancer involving seminal vesicles and pelvis lymph nodes

    Directory of Open Access Journals (Sweden)

    Birendra Rout

    2016-03-01

    Full Text Available Purpose: The main purpose of this study is to (1 identify the continual diversity between conventional fixed field intensity modulation radiotherapy (IMRT and RapidArc (RA for high-risk prostate cancer; and (2 determine potential benefits and drawbacks of using for this type of treatment.Methods: A cohort of 20 prostate cases including prostate, seminal vesicles and pelvic lymph nodes was selected for this study. The primary planning target volume (PTVP and boost planning target volume (PTVB were contoured. The total prescription dose was 75.6 Gy (45 Gy to PTVP and an additional 21.6 Gy to PTVB. Two plans were generated for each PTV: multiple 7-fields for IMRT and two arcs for RA.Results: A Sigma index (IMRT: 2.75 ± 0.581; RA: 2.8 ± 0.738 for PTVP and (IMRT: 2.0 ± 0.484; RA: 2.1 ± 0.464 for PTVB indicated similar dose homogeneity inside the PTV. Conformity index (IMRT: 0.96 ± 0.047; RA: 0.95 ± 0.059 for PTVP and (IMRT: 0.97 ± 0.015; RA: 0.96 ± 0.014 for PTVB was comparable for both the techniques. IMRT offered lower mean dose to organ at risks (OARs compared to RA plans. Normal tissue integral dose in IMRT plan resulted 0.87% lower than RA plans. All the plans displayed significant increase (2.50 times for PTVP and 1.72 for PTBB in the average number of necessary monitor units (MUs with IMRT beam. Treatment delivery time of RA was 2 ‒ 6 minutes shorter than IMRT treatment.Conclusion: For PTV including pelvic lymph nodes, seminal vesicles and prostate, IMRT offered a greater degree of OARs sparing. For PTV including seminal vesicles and prostate, RA with two arcs provided comparable plan with IMRT. RA also improved the treatment efficiency due to smaller number of MUs required.

  9. Phase II Study of Long-Term Androgen Suppression With Bevacizumab and Intensity-Modulated Radiation Therapy (IMRT) in High-Risk Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Vuky, Jacqueline, E-mail: vukyja@ohsu.edu [Section of Community Hematology/Oncology, Knight Cancer Institute, Oregon Health Sciences University, Portland, OR (United States); Pham, Huong T. [Section of Hematology/Oncology and Radiation Oncology, Virginia Mason Medical Center, Seattle, WA (United States); Warren, Sarah; Douglass, Erika [Benaroya Research Institute, Virginia Mason Medical Center, Seattle, WA (United States); Badiozamani, Kasra [Section of Hematology/Oncology and Radiation Oncology, Virginia Mason Medical Center, Seattle, WA (United States); Madsen, Berit; Hsi, Alex [Peninsula Cancer Center, Poulsbo, WA (United States); Song Guobin [Section of Hematology/Oncology and Radiation Oncology, Virginia Mason Medical Center, Seattle, WA (United States)

    2012-03-15

    Purpose: We report a Phase II trial assessing the acute and late toxicities of intensity-modulated radiation therapy (IMRT), long-term androgen suppression (LTAS), and bevacizumab in patients with high-risk localized prostate cancer. Methods and Materials: We treated 18 patients with LTAS with bicalutamide and goserelin in combination with bevacizumab and IMRT. Bevacizumab (10 mg/kg every 2 weeks) was administered for the first 16 weeks, and 15 mg/kg was then given every 3 weeks for 12 additional weeks, with an IMRT dose of 77.9 Gy to the prostate, 64.6 Gy to the seminal vesicles, and 57 Gy to the pelvic lymph nodes. Patients were eligible if they had clinical stage T2b to T4, a Gleason sum score of 8 to 10, or a prostate- specific antigen level of 20ng/mL or greater. The primary endpoint of the study was evaluation of acute and late toxicities. Results: The median age was 69 years, with a median pretreatment prostate-specific antigen level of 12.5 ng/mL and Gleason score of 8. The pretreatment clinical stage was T1c in 4 patients, T2 in 11, and T3 in 3. All patients completed IMRT with median follow-up of 34 months (range, 28-40 months) The most common Grade 2 or higher toxicities were hypertension (61% of patients with Grade 2 and 11% with Grade 3), proteinuria (28% with Grade 2 and 6% with Grade 3), and leucopenia (28% with Grade 2). No Grade 4 or higher acute toxicities were reported. Late toxicities included proctitis (6% of patients with Grade 2 and 11% with Grade 3), rectal bleeding (6% with Grade 2 and 11% with Grade 3), hematuria (6% with Grade 2), proteinuria (17% with Grade 2), hyponatremia (6% with Grade 3), cystitis (6% with Grade 3), and urinary retention (6% with Grade 2 and 11% with Grade 3). Grade 4 prostatitis occurred in 1 patient (6%). Conclusions: Bevacizumab does not appear to exacerbate the acute effects of IMRT. Late toxicities may have been worsened with this regimen. Further investigations of bevacizumab with LTAS and IMRT should be

  10. A Treatment Planning and Acute Toxicity Comparison of Two Pelvic Nodal Volume Delineation Techniques and Delivery Comparison of Intensity-Modulated Radiotherapy Versus Volumetric Modulated Arc Therapy for Hypofractionated High-Risk Prostate Cancer Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Myrehaug, Sten [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada); Chan, Gordon [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); Craig, Tim [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada); Weinberg, Vivian [Biostatistics Core, Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA (United States); Cheng, Chun [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); Roach, Mack [Department of Radiation Oncology, University of California San Francisco, San Francisco, CA (United States); Cheung, Patrick [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); Sahgal, Arjun, E-mail: arjun.sahgal@sunnybrook.ca [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada)

    2012-03-15

    Purpose: To perform a comparison of two pelvic lymph node volume delineation strategies used in intensity-modulated radiotherapy (IMRT) for high risk prostate cancer and to determine the role of volumetric modulated arc therapy (VMAT). Methods and Materials: Eighteen consecutive patients accrued to an ongoing clinical trial were identified according to either the nodal contouring strategy as described based on lymphotropic nanoparticle-enhanced magnetic resonance imaging technology (9 patients) or the current Radiation Therapy Oncology Group (RTOG) consensus guidelines (9 patients). Radiation consisted of 45 Gy to prostate, seminal vesicles, and lymph nodes, with a simultaneous integrated boost to the prostate alone, to a total dose of 67.5 Gy delivered in 25 fractions. Prospective acute genitourinary and gastrointestinal toxicities were compared at baseline, during radiotherapy, and 3 months after radiotherapy. Each patient was retrospectively replanned using the opposite method of nodal contouring, and plans were normalized for dosimetric comparison. VMAT plans were also generated according to the RTOG method for comparison. Results: RTOG plans resulted in a significantly lower rate of genitourinary frequency 3 months after treatment. The dosimetric comparison showed that the RTOG plans resulted in both favorable planning target volume (PTV) coverage and lower organs at risk (OARs) and integral (ID) doses. VMAT required two to three arcs to achieve adequate treatment plans, we did not observe consistent dosimetric benefits to either the PTV or the OARs, and a higher ID was observed. However, treatment times were significantly shorter with VMAT. Conclusion: The RTOG guidelines for pelvic nodal volume delineation results in favorable dosimetry and acceptable acute toxicities for both the target and OARs. We are unable to conclude that VMAT provides a benefit compared with IMRT.

  11. New techniques in hadrontherapy: intensity modulated proton beams.

    Science.gov (United States)

    Cella, L; Lomax, A; Miralbell, R

    2001-01-01

    Inverse planning and intensity modulated (IM) X-ray beam treatment techniques can achieve significant improvements in dose distributions comparable to those obtained with forward planned proton beams. However, intensity modulation can also be applied to proton beams and further optimization in dose distribution can reasonably be expected. A comparative planning exercise between IM X-rays and IM proton beams was carried out on two different tumor cases: a pediatric rhabdomyosarcoma and a prostate cancer. Both IM X-rays and IM protons achieved equally homogenous coverage of the target volume in the two tumor sites. Predicted NTCPs were equally low for both treatment techniques. Nevertheless, a reduced low-to-medium dose to the organs at risk and a lesser integral non-target mean dose for IM protons in the two cases favored the use of IM proton beams.

  12. SU-E-T-592: Relationship Between Dose of Distribution and Area of Segment Fields Among Different Intensity-Modulated Radiotherapy Planning in Cervix Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, R; Wang, Y; Cao, Y; Zhang, R; Shang, K; Chi, Z [Hebei Medical University Fourth Hospital, Shijiazhuang, Hebei (China)

    2014-06-01

    Purpose: In premise of uninfluenced to dose distribution of tumor target and organ at risk(OAR) in cervical cancer,area of segment fields was changed to increase efficacy and optimize treatment method by designing different plan of intensity modulated radiotherapy(IMRT). Methods: 12 cases of cervical cancer were confirmed in pathology and treated with step and shoot IMRT. Dose of PTV was 50Gy/25fractions. Every patient was designed 9 treatment plans of IMRT by Pinnacle 8.0m planning system,each plan was used with 9 beams of uniform distribution and fixing incidence direction(200°,240°,280°,320°,0°,40°,80°,120°and 160°respectively),and designed for delivery on Elekta Synergy linear accelerator. All plans were optimized with the direct machine parameter optimization(DMPO) algorithm using the same set of optimization objectives. Number of maximum segment field was defined at 80 and minimum MU in each segment was 5MU,and minimal segment area was 2*1cm{sup 2},2*2cm{sup 2},3*3cm{sup 2},4*4cm{sup 2},5*5cm{sup 2},6*6cm{sup 2},7*7cm{sup 2},8*8cm{sup 2}and 9*9cm{sup 2},respectively.Coverage,homogeneity and conformity of PTV,sparing of OAR, MU and number of segment were compared. Results: In this group, mean volume of PTV was 916.8±228.7 cm{sup 3}. Compared with the area of minimal segment field increased from 2*1cm{sup 2} to 9*9 cm{sup 2},the number of mean MU was decreased from 1405±170 to 490±47 and the number of segment field was reduced from 76±4 to 39±7 respectively(p<0.05). When the limit of minimal segment area was increased from 2*1cm{sup 2} to 7*7 cm{sup 2},dose distribution of PTV,OAR,CI,HI and V{sub 2} {sub 3} were not different (p>0.05),but when the minimal segment area was 8*8 cm{sup 2} and 9*9 cm{sup 2},they were changed compared with 7*7 cm{sup 2} and below(p<0.05). Conclusion: The minimal segment field of IMRT plan designed by Pinnacle 8.0m planning system in cervical carcinoma should be enlarge reasonably and minimal segment area of 7*7 cm

  13. Unilateral and bilateral neck SIB for head and neck cancer patients. Intensity-modulated proton therapy, tomotherapy, and RapidArc

    Energy Technology Data Exchange (ETDEWEB)

    Stromberger, Carmen; Budach, Volker; Ghadjar, Pirus; Wlodarczyk, Waldemar; Marnitz, Simone [Charite - Universitaetsmedizin Berlin, Department of Radiation Oncology and Radiotherapy, Berlin (Germany); Cozzi, Luca; Fogliata, Antonella [Humanitas Cancer Center Milan, Radiotherapy and Radiosurgery Department, Milan (Italy); Jamil, Basil [Klinikum Frankfurt Oder, Praxis fuer Strahlentherapie, Frankfurt Oder (Germany); Raguse, Jan D. [Clinic for Oral and Maxillofacial Surgery, Berlin (Germany); Boettcher, Arne [Charite - Universitaetsmedizin Berlin, Department of Otorhinolaryngology, Berlin (Germany)

    2016-04-15

    To compare simultaneous integrated boost plans for intensity-modulated proton therapy (IMPT), helical tomotherapy (HT), and RapidArc therapy (RA) for patients with head and neck cancer. A total of 20 patients with squamous cell carcinoma of the head and neck received definitive chemoradiation with bilateral (n = 14) or unilateral (n = 6) neck irradiation and were planned using IMPT, HT, and RA with 54.4, 60.8, and 70.4 GyE/Gy in 32 fractions. Dose distributions, coverage, conformity, homogeneity to planning target volumes (PTV)s and sparing of organs at risk and normal tissue were compared. All unilateral and bilateral plans showed excellent PTV coverage and acceptable dose conformity. For unilateral treatment, IMPT delivered substantially lower mean doses to contralateral salivary glands (< 0.001-1.1 Gy) than both rotational techniques did (parotid gland: 6-10 Gy; submandibular gland: 15-20 Gy). Regarding the sparing of classical organs at risk for bilateral treatment, IMPT and HT were similarly excellent and RA was satisfactory. For unilateral neck irradiation, IMPT may minimize the dry mouth risk in this subgroup but showed no advantage over HT for bilateral neck treatment regarding classical organ-at-risk sparing. All methods satisfied modern standards regarding toxicity and excellent target coverage for unilateral and bilateral treatment of head and neck cancer at the planning level. (orig.) [German] Planvergleich von intensitaetsmodulierter Protonentherapie (IMPT), Tomotherapie (HT) und RapidArc-Therapie (RA) fuer Patienten mit Plattenepithelkarzinomen der Kopf-Hals-Region unter Anwendung des simultan integrierten Boost-Konzepts (SIB). Fuer 20 Patienten mit Plattenepithelkarzinomen der Kopf-Hals-Region und bilateraler (n = 14) oder unilateraler (n = 6) zervikaler primaerer Radiochemotherapie erfolgte eine IMPT-, HT- und RA-Planung mit 54,4, 60,8 und 70,4 GyE/Gy in 32 Fraktionen. Die Dosisverteilung, Abdeckung, Konformitaet und Homogenitaet der PTVs sowie die

  14. The reoxygenation of hypoxia and the reduction of glucose metabolism in head and neck cancer by fractionated radiotherapy with intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Shozo; Shiga, Tohru; Watanabe, Shiro; Hirata, Kenji; Magota, Keiichi; Kasai, Katsuhiko; Tamaki, Nagara [Hokkaido University Graduate School of Medicine, Department of Nuclear Medicine, Hokkaido (Japan); Yasuda, Koichi; Onimaru, Rikiya; Tuchiya, Kazuhiko; Shirato, Hiroki [Hokkaido University Graduate School of Medicine, Department of Radiology, Hokkaido (Japan); Nishijima, Ken-ichi; Kuge, Yuji [Hokkaido University, Central Institute of Isotope Science, Hokkaido (Japan)

    2016-11-15

    The purpose of this study was to prospectively investigate reoxygenation in the early phase of fractionated radiotherapy and serial changes of tumoricidal effects associated with intensity-modulated radiation therapy (IMRT) in patients with head and neck cancer (HNC) using F-18 fluoromisonidazole (FMISO) PET and F-18 fluorodeoxyglucose (FDG) PET. Patients with untreated HNC underwent FMISO-PET and FDG-PET studies prospectively. A PET evaluation was conducted before each IMRT (Pre-IMRT), during IMRT (at 30 Gy/15 fr) (Inter-IMRT), and after completion of IMRT (70 Gy/35 fr) (Post-IMRT). FMISO-PET images were scanned by a PET/CT scanner at 4 h after the FMISO injection. We quantitatively analyzed the FMISO-PET images of the primary lesion using the maximum standardized uptake (SUVmax) and tumor-to-muscle ratio (TMR). The hypoxic volume (HV) was calculated as an index of tumor hypoxia, and was defined as the volume when the TMR was ≥ 1.25. Each FDG-PET scan was started 1 h after injection. The SUVmax and metabolic tumor volume (MTV) values obtained by FDG-PET were analyzed. Twenty patients finished the complete PET study protocol. At Pre-IMRT, 19 patients had tumor hypoxia in the primary tumor. In ten patients, the tumor hypoxia disappeared at Inter-IMRT. Another seven patients showed the disappearance of tumor hypoxia at Post-IMRT. Two patients showed tumor hypoxia at Post-IMRT. The FMISO-PET results showed that the reduction rates of both SUVmax and TMR from Pre-IMRT to Inter-IMRT were significantly higher than the corresponding reductions from Inter-IMRT to Post-IMRT (SUVmax: 27 % vs. 10 %, p = 0.025; TMR: 26 % vs. 12 %, p = 0.048). The reduction rate of SUVmax in FDG-PET from Pre-IMRT to Inter-IMRT was similar to that from Inter-IMRT to Post-IMRT (47 % vs. 48 %, p = 0.778). The reduction rate of the HV in FMISO-PET from Pre-IMRT to Inter-IMRT tended to be larger than that from Inter-IMRT to Post-IMRT (63 % vs. 40 %, p = 0.490). Conversely, the reduction rate of

  15. Dosimetric and geometric evaluation of the use of deformable image registration in adaptive intensity-modulated radiotherapy for head-and-neck cancer

    DEFF Research Database (Denmark)

    Eiland, R B; Maare, Christian; Sjöström, D

    2014-01-01

    The aim of this study was to carry out geometric and dosimetric evaluation of the usefulness of a deformable image registration algorithm utilized for adaptive head-and-neck intensity-modulated radiotherapy. Data consisted of seven patients, each with a planning CT (pCT), a rescanning CT (Re...... larger differences were observed for organs at risk. The deformed structures cannot fully replace manually delineated structures. Based on both geometrical and dosimetrical measures, there is a tendency for the dCT to overestimate the need for replanning, compared with the ReCT....

  16. Linear algebraic methods applied to intensity modulated radiation therapy.

    Science.gov (United States)

    Crooks, S M; Xing, L

    2001-10-01

    Methods of linear algebra are applied to the choice of beam weights for intensity modulated radiation therapy (IMRT). It is shown that the physical interpretation of the beam weights, target homogeneity and ratios of deposited energy can be given in terms of matrix equations and quadratic forms. The methodology of fitting using linear algebra as applied to IMRT is examined. Results are compared with IMRT plans that had been prepared using a commercially available IMRT treatment planning system and previously delivered to cancer patients.

  17. Virtual bolus for inversely planned intensity modulated radiotherapy in adjuvant breast cancer treatment; Virtueller Bolus zur inversen Bestrahlungsplanung bei intensitaetsmodulierter Radiotherapie des Mammakarzinoms im Rahmen der adjuvanten Therapie

    Energy Technology Data Exchange (ETDEWEB)

    Thilmann, C.; Grosser, K.H.; Rhein, B.; Zabel, A. [Deutsches Krebsforschungszentrum Heidelberg (Germany). Klinische Kooperationseinheit Strahlentherapie; Wannenmacher, M. [Heidelberg Univ. (Germany). Klinische Radiologie; Debus, J. [Deutsches Krebsforschungszentrum Heidelberg (Germany). Klinische Kooperationseinheit Strahlentherapie; Heidelberg Univ. (Germany). Klinische Radiologie

    2002-03-01

    Background: Intensity modulated radiotherapy (IMRT) provides better sparing of normal tissue. We investigated the feasibility of inverse treatment planning for IMRT in adjuvant radiotherapy for breast cancer. Material and Methods: In addition to radiotherapy planning in conventional technique with tangential wedged 6-MV-photon beams we performed inversely planned IMRT (KonRad trademark). In the CT scans for treatment planning we defined a 10-mm bolus of -60 HE density. The influence of this bolus on planning optimization was determined by optimization without and dose calculation with and without bolus. Dose calculation after dose optimization with bolus was performed using different bolus thickness to determine the influence of the bolus on dose calculation. The results were compared with dose distribution in conventional technique. Results: Inverse optimization with a dose algorithm which considers tissue inhomogeneity results in unintended dose increase at the patient surface. With a virtual 10-mm bolus used for inverse optimization the dose increase was reduced. Thus, skin sparing was identical to conventional planning. The relative dose distribution was negligibly affected by the use of a 10-mm bolus. Difference in absolute dose was 3.4% compared to calculation without bolus. Therefore, the bolus must be removed before final dose calculation. (orig.) [German] Fragestellung: Die intensitaetsmodulierte Strahlenbehandlung (IMRT) verspricht eine verbesserte Schonung von Risikostrukturen. Wir untersuchten, in welcher Form eine inverse Bestrahlungsplanung zur IMRT der Restbrust beim Mammakarzinom durchfuehrbar ist. Methodik: Neben einer Bestrahlungsplanung in konventioneller Technik mit tangentialen 6-MB-Keilfilter-Feldern wurde eine IMRT-Bestrahlungsplanung mit inverser Planoptimierung (KonRad trademark) durchgefuehrt. Im Planungs-CT wurde ein Bolus von 10 mm Dicke und einer Dichte von -60 HE definiert. Der Einfluss des Bolus auf die Planoptimierung wurde bestimmt

  18. Arc binary intensity modulated radiation therapy (AB IMRT)

    Science.gov (United States)

    Yang, Jun

    The state of the art Intensity Modulate Radiation Therapy (IMRT) has been one of the most significant breakthroughs in the cancer treatment in the past 30 years. There are two types of IMRT systems. The first system is the binary-based tomotherapy, represented by the Peacock (Nomos Corp) and Tomo unit (TomoTherapy Inc.), adopting specific binary collimator leafs to deliver intensity modulated radiation fields in a serial or helical fashion. The other uses the conventional dynamic multileaf collimator (MLC) to deliver intensity modulated fields through a number of gantry positions. The proposed Arc Binary IMRT attempts to deliver Tomo-like IMRT with conventional dynamic MLC and combines the advantages of the two types of IMRT techniques: (1) maximizing the number of pencil beams for better dose optimization, (2) enabling conventional linear accelerator with dynamic MLC to deliver Tomo-like IMRT. In order to deliver IMRT with conventional dynamic MLC in a binary fashion, the slice-by-slice treatment with limited slice thickness has been proposed in the thesis to accommodate the limited MLC traveling speed. Instead of moving the patient to subsequent treatment slices, the proposed method offsets MLC to carry out the whole treatment, slice by slice sequentially, thus avoid patient position error. By denoting one arc pencil beam set as a gene, genetic algorithm (GA) is used as the searching engine for the dose optimization process. The selection of GA parameters is a crucial step and has been studied in depth so that the optimization process will converge with reasonable speed. Several hypothetical and clinical cases have been tested with the proposed IMRT method. The comparison of the dose distribution with other commercially available IMRT systems demonstrates the clear advantage of the new method. The proposed Arc Binary Intensity Modulated Radiation Therapy is not only theoretically sound but practically feasible. The implementation of this method would expand the

  19. Late xerostomia after intensity-modulated conformational radiotherapy of upper aero-digestive tract cancers: study 2004-03 by the head and neck oncology and radiotherapy Group (Gortec); Xerostomie tardive apres radiotherapie conformationnelle avec modulation d'intensite des cancers des voies aero-digestives superieures: etude 2004-03 du Groupe oncologie et radiotherapie de la tete et du cou (Gortec)

    Energy Technology Data Exchange (ETDEWEB)

    Toledano, I.; Lapeyre, M. [Centre Jean-Perrin, 63 - Clermont-Ferrand (France); Graff, P. [Centre Alexis-Vautrin, 54 - Vandoeuvre-les-Nancy (France); Serre, C. [Centre Val d' Aurelle, 34 - Montpellier (France); Bensadoun, R.J. [CHU La Miletrie, 86 - Poitiers (France); Bensadoun, R.J.; Ortholan, C. [Centre Antoine-Lacassagne, 06 - Nice (France); Calais, G. [CHU Bretonneau, 37 - Tours (France); Alfonsi, M. [Institut Sainte-Catherine, 84 - Avignon (France); Giraud, P. [Institut Curie, 75 - Paris (France); Hopital europeen Georges-Pompidou, 75 - Paris (France); Racadot, S. [Centre Leon-Berrard, 69 - Lyon (France)

    2010-10-15

    The authors report a retrospective assessment of late xerostomia according to the RTOG (Radiation Therapy Oncology Group) classification of the European Organization for Research and Treatment of Cancer (EORTC) among patients treated by intensity-modulated conformational radiotherapy (IMRT) and suffering from upper aero-digestive tract carcinomas of different stages. Some of these patients have bee operated, and some have been treated by chemotherapy. It appears that the IMRT results in a reduction of late xerostomia, and even in an absence of salivary toxicity. Short communication

  20. Conformal radiotherapy with intensity modulation and integrated boost in the head and neck cancers: experience of the Curie Institute; Radiotherapie conformationnelle avec modulation d'intensite et boost integre des cancers de la tete et du cou: experience de l'institut Curie

    Energy Technology Data Exchange (ETDEWEB)

    Toledano, I.; Serre, A.; Bensadoun, R.J.; Ortholan, C.; Racadot, S.; Calais, G.; Alfonsi, M.; Giraud, P. [Centre Jean-Perrin, 63 - Clermont-Ferrand (France); Graff, P.; Serre, A.; Bensadoun, R.J.; Ortholan, C.; Racadot, S.; Calais, G.; Alfonsi, M.; Giraud, P. [Hopital Europeen Georges-Pompidou, 75 -Paris (France)

    2009-10-15

    The modulated intensity radiotherapy (I.M.R.T.) is used in the treatment of cancers in superior aero digestive tracts to reduce the irradiation of parotids and to reduce the delayed xerostomia. This retrospective study presents the results got on the fourteen first patients according an original technique of I.M.R.T. with integrated boost. It appears that this technique is feasible and allows to reduce the xerostomia rate without modifying the local control rate. To limit the average dose to the parotids under 30 Gy seems reduce the incidence of severe xerostomia. (N.C.)

  1. Intensity-modulated arc therapy with simultaneous integrated boost in the treatment of primary irresectable cervical cancer. Treatment planning, quality control, and clinical implementation

    Energy Technology Data Exchange (ETDEWEB)

    Vandecasteele, Katrien; De Neve, Wilfried; De Gersem, Werner; Paelinck, Leen; Fonteyne, Valerie; De Wagter, Carlos; De Meerleer, Gert [Dept. of Radiotherapy, Ghent Univ. Hospital (Belgium); Delrue, Louke; Villeirs, Geert [Dept. of Radiology, Ghent Univ. Hospital (Belgium); Makar, Amin [Dept. of Gynecology, Ghent Univ. Hospital (Belgium)

    2009-12-15

    Purpose: to report on the planning procedure, quality control, and clinical implementation of intensity-modulated arc therapy (IMAT) delivering a simultaneous integrated boost (SIB) in patients with primary irresectable cervix carcinoma. Patients and methods: six patients underwent PET-CT (positron emission tomography-computed tomography) and MRI (magnetic resonance imaging) before treatment planning. Prescription (25 fractions) was (1) a median dose (D{sub 50}) of 62, 58 and 56 Gy to the primary tumor (GTVcervix), primary clinical target volume (CTVcervix) and its planning target volume (PTVcervix), respectively; (2) a D{sub 50} of 60 Gy to the PET-positive lymph nodes (GTVnodes); (3) a minimal dose (D{sub 98}) of 45 Gy to the planning target volume of the elective lymph nodes (PTVnodes). IMAT plans were generated using an anatomy-based exclusion tool with the aid of weight and leaf position optimization. The dosimetric delivery of IMAT was validated preclinically using radiochromic film dosimetry. Results: five to nine arcs were needed to create valid IMAT plans. Dose constraints on D{sub 50} were not met in two patients (both GTVcervix: 1 Gy and 3 Gy less). D{sub 98} for PTVnodes was not met in three patients (1 Gy each). Film dosimetry showed excellent gamma evaluation. There were no treatment interruptions. Conclusion: IMAT allows delivering an SIB to the macroscopic tumor without compromising the dose to the elective lymph nodes or the organs at risk. The clinical implementation is feasible. (orig.)

  2. Implementation of intensity modulation with dynamic multileaf collimation

    Energy Technology Data Exchange (ETDEWEB)

    Wong, J.W.; Yu, C.; Jaffray, D. [William Beaumont Hospital, Royal Oak, MI (United States)

    1995-12-01

    The computer-controlled multileaf collimator (MLC) marks one of the most important advances in radiation therapy. The device efficiently replaces manual blocking to shape fields and can be used to modulate beam intensity. The results of a research programme at William Beaumont Hospital, aimed at bringing dynamic intensity modulation into clinical use, are discussed.

  3. Effects of intensity-modulated radiotherapy on human oral microflora.

    Science.gov (United States)

    Shao, Zi-Yang; Tang, Zi-Sheng; Yan, Chao; Jiang, Yun-Tao; Ma, Rui; Liu, Zheng; Huang, Zheng-Wei

    2011-01-01

    This study aimed to evaluate changes in the biodiversity of the oral microflora of patients with head and neck cancer treated with postoperative intensity-modulated radiotherapy (IMRT) or conventional radiotherapy (CRT). Pooled dental plaque samples were collected during the radiation treatment from patients receiving IMRT (n = 13) and CRT (n = 12). Denaturing gradient gel electrophoresis (DGGE) was used to analyze the temporal variation of these plaque samples. The stimulated and unstimulated salivary flow rates were also compared between IMRT and CRT patients. Reductions in the severity of hyposalivation were observed in IMRT patients compared with CRT patients. We also observed that the temporal stability of the oral ecosystem was significantly higher in the IMRT group (69.96 ± 7.82%) than in the CRT group (51.98 ± 10.45%) (P oral ecosystem than CRT.

  4. DFB laser with attached external intensity modulator

    Energy Technology Data Exchange (ETDEWEB)

    Marcuse, D. (AT and T Bell Labs. Holmdel, NJ (US))

    1990-02-01

    This paper presents a theoretical study of the frequency pulling effect exerted on a DFB laser by an external amplitude modulator that is directly attached to it. The modulator consists of a piece of waveguide whose loss is modulated by means of an externally applied voltage. The modulator affects the laser due to residual reflections from its far end which appear as a variable effective reflectivity to the output end of the DFB laser. Modulation affects the magnitude as well as the phase of the effective reflection coefficient presented to the laser due to the coupling of the real and imaginary parts of the effective refractive index of the modulator waveguide. The tuning problem is formulated as an eigenvalue equation for the DFB laser in the presence of an externally attached lossy cavity.

  5. Increase in tumor control and normal tissue complication probabilities in advanced head-and-neck cancer for dose-escalated intensity-modulated photon and proton therapy

    Directory of Open Access Journals (Sweden)

    Annika eJakobi

    2015-11-01

    Full Text Available Introduction:Presently used radio-chemotherapy regimens result in moderate local control rates for patients with advanced head and neck squamous cell carcinoma (HNSCC. Dose escalation (DE may be an option to improve patient outcome, but may also increase the risk of toxicities in healthy tissue. The presented treatment planning study evaluated the feasibility of two DE levels for advanced HNSCC patients, planned with either intensity-modulated photon therapy (IMXT or proton therapy (IMPT.Materials and Methods:For 45 HNSCC patients, IMXT and IMPT treatment plans were created including DE via a simultaneous integrated boost (SIB in the high-risk volume, while maintaining standard fractionation with 2 Gy per fraction in the remaining target volume. Two DE levels for the SIB were compared: 2.3 Gy and 2.6 Gy. Treatment plan evaluation included assessment of tumor control probabilities (TCP and normal tissue complication probabilities (NTCP.Results:An increase of approximately 10% in TCP was estimated between the DE levels. A pronounced high-dose rim surrounding the SIB volume was identified in IMXT treatment. Compared to IMPT, this extra dose slightly increased the TCP values and to a larger extent the NTCP values. For both modalities, the higher DE level led only to a small increase in NTCP values (mean differences < 2% in all models, except for the risk of aspiration, which increased on average by 8% and 6% with IMXT and IMPT, respectively, but showed a considerable patient dependence. Conclusions:Both DE levels appear applicable to patients with IMXT and IMPT since all calculated NTCP values, except for one, increased only little for the higher DE level. The estimated TCP increase is of relevant magnitude. The higher DE schedule needs to be investigated carefully in the setting of a prospective clinical trial, especially regarding toxicities caused by high local doses that lack a sound dose response description, e.g., ulcers.

  6. Correlation of Osteoradionecrosis and Dental Events With Dosimetric Parameters in Intensity-Modulated Radiation Therapy for Head-and-Neck Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Daniel R., E-mail: dgomez@mdanderson.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Estilo, Cherry L. [Dental Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Wolden, Suzanne L.; Zelefsky, Michael J. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Kraus, Dennis H.; Wong, Richard J.; Shaha, Ashok R.; Shah, Jatin P. [Department of Head and Neck Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Mechalakos, James G.; Lee, Nancy Y. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    2011-11-15

    Purpose: Osteoradionecrosis (ORN) is a known complication of radiation therapy to the head and neck. However, the incidence of this complication with intensity-modulated radiation therapy (IMRT) and dental sequelae with this technique have not been fully elucidated. Methods and Materials: From December 2000 to July 2007, 168 patients from our institution have been previously reported for IMRT of the oral cavity, nasopharynx, larynx/hypopharynx, sinus, and oropharynx. All patients underwent pretreatment dental evaluation, including panoramic radiographs, an aggressive fluoride regimen, and a mouthguard when indicated. The median maximum mandibular dose was 6,798 cGy, and the median mean mandibular dose was 3,845 cGy. Patient visits were retrospectively reviewed for the incidence of ORN, and dental records were reviewed for the development of dental events. Univariate analysis was then used to assess the effect of mandibular and parotid gland dosimetric parameters on dental endpoints. Results: With a median clinic follow-up of 37.4 months (range, 0.8-89.6 months), 2 patients, both with oral cavity primaries, experienced ORN. Neither patient had preradiation dental extractions. The maximum mandibular dose and mean mandibular dose of the 2 patients were 7,183 and 6,828 cGy and 5812 and 5335 cGy, respectively. In all, 17% of the patients (n = 29) experienced a dental event. A mean parotid dose of >26 Gy was predictive of a subsequent dental caries, whereas a maximum mandibular dose >70 Gy and a mean mandibular dose >40 Gy were correlated with dental extractions after IMRT. Conclusions: ORN is rare after head-and-neck IMRT, but is more common with oral cavity primaries. Our results suggest different mechanisms for radiation-induced caries versus extractions.

  7. PET-Adjusted Intensity Modulated Radiation Therapy and Combination Chemotherapy in Treating Patients With Stage II-IV Non-small Cell Lung Cancer

    Science.gov (United States)

    2017-01-23

    Metastatic Malignant Neoplasm in the Brain; Recurrent Non-Small Cell Lung Carcinoma; Stage IIA Non-Small Cell Lung Carcinoma; Stage IIB Non-Small Cell Lung Carcinoma; Stage IIIA Non-Small Cell Lung Cancer; Stage IIIB Non-Small Cell Lung Cancer; Stage IV Non-Small Cell Lung Cancer

  8. Comparing two strategies of dynamic intensity modulated radiation therapy (dIMRT with 3-dimensional conformal radiation therapy (3DCRT in the hypofractionated treatment of high-risk prostate cancer

    Directory of Open Access Journals (Sweden)

    Yartsev Slav

    2008-01-01

    Full Text Available Abstract Background To compare two strategies of dynamic intensity modulated radiation therapy (dIMRT with 3-dimensional conformal radiation therapy (3DCRT in the setting of hypofractionated high-risk prostate cancer treatment. Methods 3DCRT and dIMRT/Helical Tomotherapy(HT planning with 10 CT datasets was undertaken to deliver 68 Gy in 25 fractions (prostate and simultaneously delivering 45 Gy in 25 fractions (pelvic lymph node targets in a single phase. The paradigms of pelvic vessel targeting (iliac vessels with margin are used to target pelvic nodes and conformal normal tissue avoidance (treated soft tissues of the pelvis while limiting dose to identified pelvic critical structures were assessed compared to 3DCRT controls. Both dIMRT/HT and 3DCRT solutions were compared to each other using repeated measures ANOVA and post-hoc paired t-tests. Results When compared to conformal pelvic vessel targeting, conformal normal tissue avoidance delivered more homogenous PTV delivery (2/2 t-test comparisons; p dose, 1–3 Gy over 5/10 dose points; p Conclusion dIMRT/HT nodal and pelvic targeting is superior to 3DCRT in dose delivery and critical structure sparing in the setting of hypofractionation for high-risk prostate cancer. The pelvic targeting paradigm is a potential solution to deliver highly conformal pelvic radiation treatment in the setting of nodal location uncertainty in prostate cancer and other pelvic malignancies.

  9. Prone Breast Intensity Modulated Radiation Therapy: 5-Year Results

    Energy Technology Data Exchange (ETDEWEB)

    Osa, Etin-Osa O.; DeWyngaert, Keith [Department of Radiation Oncology, New York University School of Medicine, New York, New York (United States); Roses, Daniel [Department of Surgery, New York University School of Medicine, New York, New York (United States); Speyer, James [Department of Medical Oncology, New York University School of Medicine, New York, New York (United States); Guth, Amber; Axelrod, Deborah [Department of Surgery, New York University School of Medicine, New York, New York (United States); Fenton Kerimian, Maria [Department of Radiation Oncology, New York University School of Medicine, New York, New York (United States); Goldberg, Judith D. [Department of Population Health, New York University School of Medicine, New York, New York (United States); Formenti, Silvia C., E-mail: Silvia.formenti@nyumc.org [Department of Radiation Oncology, New York University School of Medicine, New York, New York (United States)

    2014-07-15

    Purpose: To report the 5-year results of a technique of prone breast radiation therapy delivered by a regimen of accelerated intensity modulated radiation therapy with a concurrent boost to the tumor bed. Methods and Materials: Between 2003 and 2006, 404 patients with stage I-II breast cancer were prospectively enrolled into 2 consecutive protocols, institutional trials 03-30 and 05-181, that used the same regimen of 40.5 Gy/15 fractions delivered to the index breast over 3 weeks, with a concomitant daily boost to the tumor bed of 0.5 Gy (total dose 48 Gy). All patients were treated after segmental mastectomy and had negative margins and nodal assessment. Patients were set up prone: only if lung or heart volumes were in the field was a supine setup attempted and chosen if found to better spare these organs. Results: Ninety-two percent of patients were treated prone, 8% supine. Seventy-two percent had stage I, 28% stage II invasive breast cancer. In-field lung volume ranged from 0 to 228.27 cm{sup 3}, mean 19.65 cm{sup 3}. In-field heart volume for left breast cancer patients ranged from 0 to 21.24 cm{sup 3}, mean 1.59 cm{sup 3}. There was no heart in the field for right breast cancer patients. At a median follow-up of 5 years, the 5-year cumulative incidence of isolated ipsilateral breast tumor recurrence was 0.82% (95% confidence interval [CI] 0.65%-1.04%). The 5-year cumulative incidence of regional recurrence was 0.53% (95% CI 0.41%-0.69%), and the 5-year overall cumulative death rate was 1.28% (95% CI 0.48%-3.38%). Eighty-two percent (95% CI 77%-85%) of patients judged their final cosmetic result as excellent/good. Conclusions: Prone accelerated intensity modulated radiation therapy with a concomitant boost results in excellent local control and optimal sparing of heart and lung, with good cosmesis. Radiation Therapy Oncology Group protocol 1005, a phase 3, multi-institutional, randomized trial is ongoing and is evaluating the equivalence of a similar dose and

  10. Dosimetric Predictors of Duodenal Toxicity After Intensity Modulated Radiation Therapy for Treatment of the Para-aortic Nodes in Gynecologic Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Jonathan [Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida (United States); Sulman, Erik P.; Jhingran, Anuja [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Tucker, Susan L. [Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Rauch, Gaiane M. [Department of Radiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Eifel, Patricia J. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Klopp, Ann H., E-mail: aklopp@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2014-02-01

    Purpose: To determine the incidence of duodenal toxicity in patients receiving intensity modulated radiation therapy (IMRT) for treatment of para-aortic nodes and to identify dosimetric parameters predictive of late duodenal toxicity. Methods and Materials: We identified 105 eligible patients with gynecologic malignancies who were treated with IMRT for gross metastatic disease in the para-aortic nodes from January 1, 2005, through December 31, 2009. Patients were treated to a nodal clinical target volume to 45 to 50.4 Gy with a boost to 60 to 66 Gy. The duodenum was contoured, and dosimetric data were exported for analysis. Duodenal toxicity was scored according to Radiation Therapy Oncology Group criteria. Univariate Cox proportional hazards analysis and recursive partitioning analysis were used to determine associations between dosimetric variables and time to toxicity and to identify the optimal threshold that separated patients according to risk of toxicity. Results: Nine of the 105 patients experienced grade 2 to grade 5 duodenal toxicity, confirmed by endoscopy in all cases. The 3-year actuarial rate of any duodenal toxicity was 11.7%. A larger volume of the duodenum receiving 55 Gy (V55) was associated with higher rates of duodenal toxicity. The 3-year actuarial rates of duodenal toxicity with V55 above and below 15 cm{sup 3} were 48.6% and 7.4%, respectively (P<.01). In Cox univariate analysis of dosimetric variables, V55 was associated with duodenal toxicity (P=.029). In recursive partitioning analysis, V55 less than 13.94% segregated all patients with duodenal toxicity. Conclusions: Dose-escalated IMRT can safely and effectively treat para-aortic nodal disease in gynecologic malignancies, provided that care is taken to limit the dose to the duodenum to reduce the risk of late duodenal toxicity. Limiting V55 to below 15 cm{sup 3} may reduce the risk of duodenal complications. In cases where the treatment cannot be delivered within these constraints

  11. Patterns and predictors of amelioration of genitourinary toxicity after high-dose intensity-modulated radiation therapy for localized prostate cancer

    DEFF Research Database (Denmark)

    Ghadjar, Pirus; Jackson, Andrew D.; Spratt, Daniel E;

    2013-01-01

    Treatment-related toxicity and quality of life (QoL) considerations are important when counseling patients with localized prostate cancer (PCa).......Treatment-related toxicity and quality of life (QoL) considerations are important when counseling patients with localized prostate cancer (PCa)....

  12. Hypoxia imaging with [18F]-FMISO-PET for guided dose escalation with intensity-modulated radiotherapy in head-and-neck cancers

    Energy Technology Data Exchange (ETDEWEB)

    Henriques de Figueiredo, B. [Institut Bergonie, Department of Radiotherapy, Bordeaux (France); INCIA UMR-CNRS 5287, Bordeaux (France); Zacharatou, C. [Institut Bergonie, Department of Radiotherapy, Bordeaux (France); Galland-Girodet, S.; Benech, J. [Hospital Haut-Leveque, Department of Radiotherapy, CHRU Bordeaux (France); Clermont-Gallerande, H. de [Hospital Pellegrin, Department of Nuclear Medicine, CHRU Bordeaux (France); Lamare, F. [INCIA UMR-CNRS 5287, Bordeaux (France); Hospital Haut-Leveque, Department of Radiotherapy, CHRU Bordeaux (France); Hatt, M. [LaTIM INSERM U1101, Brest (France); Digue, L. [Hospital Saint-Andre, Department of Clinical Oncology, CHRU Bordeaux (France); Mones del Pujol, E. de [Department of Oto-rhino-laryngology, CHRU Bordeaux (France); Fernandez, P. [INCIA UMR-CNRS 5287, Bordeaux (France); Hospital Pellegrin, Department of Nuclear Medicine, CHRU Bordeaux (France); University Bordeaux 2, Bordeaux (France)

    2014-09-23

    Positron emission tomography (PET) with [{sup 18}F]-fluoromisonidazole ([{sup 18}F]-FMISO) provides a non-invasive assessment of hypoxia. The aim of this study is to assess the feasibility of a dose escalation with volumetric modulated arc therapy (VMAT) guided by [{sup 18}F]-FMISO-PET for head-and-neck cancers (HNC). Ten patients with inoperable stages III-IV HNC underwent [{sup 18}F]-FMISO-PET before radiotherapy. Hypoxic target volumes (HTV) were segmented automatically by using the fuzzy locally adaptive Bayesian method. Retrospectively, two VMAT plans were generated delivering 70 Gy to the gross tumour volume (GTV) defined on computed tomography simulation or 79.8 Gy to the HTV. A dosimetric comparison was performed, based on calculations of tumour control probability (TCP), normal tissue complication probability (NTCP) for the parotid glands and uncomplicated tumour control probability (UTCP). The mean hypoxic fraction, defined as the ratio between the HTV and the GTV, was 0.18. The mean average dose for both parotids was 22.7 Gy and 25.5 Gy without and with dose escalation respectively. FMISO-guided dose escalation led to a mean increase of TCP, NTCP for both parotids and UTCP by 18.1, 4.6 and 8 % respectively. A dose escalation up to 79.8 Gy guided by [{sup 18}F]-FMISO-PET with VMAT seems feasible with improvement of TCP and without excessive increase of NTCP for parotids. (orig.) [German] Die Positronenemissionstomographie (PET) mit [{sup 18}F]-Fluoromisonidazol ([{sup 18}F]-FMISO) ermoeglicht eine nichtinvasive Beurteilung der Hypoxie. Ziel dieser Studie ist es, die Durchfuehrbarkeit einer [{sup 18}F]-FMISO-PET-gefuehrten Dosissteigerung bei volumetrisch modulierter Arc-Therapie (VMAT) von Kopf-Hals-Tumoren (KHT) zu bewerten. Zehn Patienten mit inoperablen KHT der Stadien III-IV erhielten vor der Strahlentherapie eine [{sup 18}F]-FMISO-PET. Hypoxische Zielvolumina (HV) wurden automatisch mit Hilfe des FLAB(Fuzzy Locally Adaptive Bayesian

  13. Prostate and seminal vesicle volume based consideration of prostate cancer patients for treatment with 3D-conformal or intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, Nandanuri M. S.; Nori, Dattatreyudu; Chang, Hyesook; Lange, Christopher S.; Ravi, Akkamma [Department of Radiation Oncology, New York Hospital Queens, Flushing, New York 11355 (United States); Department of Radiation Oncology, State University of New York Downstate Medical Center, Brooklyn, New York 11203 (United States); Department of Radiation Oncology, New York Hospital Queens, Flushing, New York 11355 (United States)

    2010-07-15

    Purpose: The purpose of this article was to determine the suitability of the prostate and seminal vesicle volumes as factors to consider patients for treatment with image-guided 3D-conformal radiation therapy (3D-CRT) or intensity-modulated radiation therapy (IMRT), using common dosimetry parameters as comparison tools. Methods: Dosimetry of 3D and IMRT plans for 48 patients was compared. Volumes of prostate, SV, rectum, and bladder, and prescriptions were the same for both plans. For both 3D and IMRT plans, expansion margins to prostate+SV (CTV) and prostate were 0.5 cm posterior and superior and 1 cm in other dimensions to create PTV and CDPTV, respectively. Six-field 3D plans were prepared retrospectively. For 3D plans, an additional 0.5 cm margin was added to PTV and CDPTV. Prescription for both 3D and IMRT plans was the same: 45 Gy to CTV followed by a 36 Gy boost to prostate. Dosimetry parameters common to 3D and IMRT plans were used for comparison: Mean doses to prostate, CDPTV, SV, rectum, bladder, and femurs; percent volume of rectum and bladder receiving 30 (V30), 50 (V50), and 70 Gy (V70), dose to 30% of rectum and bladder, minimum and maximum point dose to CDPTV, and prescription dose covering 95% of CDPTV (D95). Results: When the data for all patients were combined, mean dose to prostate and CDPTV was higher with 3D than IMRT plans (P<0.01). Mean D95 to CDPTV was the same for 3D and IMRT plans (P>0.2). On average, among all cases, the minimum point dose was less for 3D-CRT plans and the maximum point dose was greater for 3D-CRT than for IMRT (P<0.01). Mean dose to 30% rectum with 3D and IMRT plans was comparable (P>0.1). V30 was less (P<0.01), V50 was the same (P>0.2), and V70 was more (P<0.01) for rectum with 3D than IMRT plans. Mean dose to bladder was less with 3D than IMRT plans (P<0.01). V30 for bladder with 3D plans was less than that of IMRT plans (P<0.01). V50 and V70 for 3D plans were the same for 3D and IMRT plans (P>0.2). Mean dose to femurs

  14. 宫颈癌术后骨髓保护调强放疗研究%Bone marrow-sparing intensity-modulated radiotherapy for postoperative treatment of cervical cancer

    Institute of Scientific and Technical Information of China (English)

    Fuli Zhang; Mingmin Zheng; Junmao Gao; Weidong Xu

    2011-01-01

    Objective: The aim of this study was to compare bone marrow-sparing intensity-modulated radiotherapy (IMRT)with IMRT without entering pelvic bone marrow as a planning constraint in the treatment of cervical cancer after hysterectomy. Methods: For a cohort of 10 patients, bone marrow-sparing IMRT and routine IMRT planning were designed. Theproscribed dose was 45 Gy/1.8 Gy/25f, 95% of the planning target volume received this dose. Doses were computed with a commercially available treatment planning system (TPS) using convolution/superimposition (CS) algorithm. Plans were compared according to dose-volume histogram (DVH) analysis in terms of planning target volume (PTV) homogeneity and conformity indices (HI and CI) as well as organs at risk (OARs) dose and volume parameters. Results: Bone marrow-sparing IMRT had an vantages over routine IMRT in terms of CI, but inferior to the latter for HI. Compared with routine IMRT, V5,V10, V20, V30, V40 of pelvic bone marrow of bone marrow-sparing IMRT reduced by 1.81%, 8.61%, 31.81%, 29.50%, 28.29%,respectively. No statistically significant differences were observed between bone marrow-sparing IMRT and routine IMRT in terms of small bowel, bladder and rectum. Conclusion: For patients with cervical cancer after hysterectomy, bone marrowsparing IMRT reduced the pelvic bone marrow volume irradiated at all dose levels and might be conducive to preventing the occurrence of acute bone marrow toxicity.

  15. Head and neck intensity modulated radiation therapy leads to an increase of opportunistic oral pathogens

    NARCIS (Netherlands)

    Schuurhuis, Jennifer M.; Stokman, Monique A.; Witjes, Max J. H.; Langendijk, Johannes A.; van Winkelhoff, Arie J.; Vissink, Arjan; Spijkervet, Frederik K. L.

    2016-01-01

    Objectives: The introduction of intensity modulated radiation therapy (IMRT) has led to new possibilities in the treatment of head and neck cancer (HNC). Limited information is available on how this more advanced radiation technique affects the oral microflora. In a prospective study we assessed the

  16. Performance analysis of the ultra-linear optical intensity modulator

    Science.gov (United States)

    Madamopoulos, Nicholas; Dingel, Benjamin

    2006-10-01

    The linear optical intensity modulator is a key component in any broadband optical access-based analog fiber-optic link systems such as sub-carrier multiplexing (SCM) systems, ultra-dense CATV, Radio-over-Fiber (RoF) communications, and other platform access systems. Previously, we have proposed a super-linear optical modulator, having SFDR = 130 -140 dB-Hz 2/3, based on a unique combination of phase-modulator (PM) and a weak ring resonator (RR) modulator within a Mach-Zehnder interferometer (MZI). We presented some of its unique features. In this paper, we characterize further this ultra-linear optical intensity modulator, analyze its RF performance and provide method for parameter optimization. Other excellent features of this modulator design such as high manufacturing tolerance, effect of link insertion loss, adaptive characteristic and device simplicity are also discussed.

  17. Implementation of Constant Dose Rate and Constant Angular Spacing Intensity-modulated Arc Therapy for Cervical Cancer by Using a Conventional Linear Accelerator

    Directory of Open Access Journals (Sweden)

    Ruo-Hui Zhang

    2016-01-01

    Conclusions: Patients with cervical cancer treated with CDR-CAS-IMAT using Varian Clinical 23EX can get equivalent or superior dose distribution compared to those treated with IMRT. CDR-CAS-IMAT has a less treatment time and MU, which can reduce the uncertainty factor and patient discomfort in treatment.

  18. SU-E-T-57: A Novel Method to Improve Dose Heterogeneity of Target and Organs at Risk Sparing in the Intensity-Modulated Radiotherapy for Stage III Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Huang, B-T; Lu, J-Y [Cancer Hospital of Shantou University Medical College, Shantou (China)

    2015-06-15

    Purpose: Intensity-modulated radiotherapy (IMRT) treatment for lung cancer is difficult due to the heterogeneous dose distribution and excessive dose to the organs at risk (OARs). We introduce a simple method based on the base dose function (BDF) in Eclipse treatment planning system to overcome the difficulties. Methods: Thirteen patients suffered from stage III non-small cell lung cancer (NSCLC) were enrolled in the study. Three kinds of approaches were applied to obtain clinically acceptable treatment plans: 1) conventionally optimizing method with hot and cold spots re-optimization (CO); 2) target-divided optimizing method (TDO) in which the optimization objective in the lung density of planning target volume (PTV) was set to 2 to 4 Gy higher than in the soft tissue density; 3) base dose function (BDF) in which the treatment plan was produced based on the original plan for re-optimization. CO, TDO and BDF methods were then compared in terms of conformity index (CI), homogeneity index (HI), OARs sparing and monitor units (MUs). Additionally, delta4, portal dosimetry and IMSure were used to measure the dose delivering accuracy. Results: The BDF technique provided more superior CI and HI than the other two methods. Moreover, the new method also reduced the lung, esophagus, heart and spinal cord dose. However, the BDF plans needed extra 15% and 10% MUs than the CO and TDO methods. Dose verification results demonstrated good and comparable γ pass rates among the three methods. Conclusion: The proposed BDF method greatly improves the dose homogeneity and OARs sparing in the IMRT treatment for lung cancer.

  19. Clinical study on intensity modulated radiation therapy combined with thermotherapy in treating advanced rectum cancer%IMRT联合热疗治疗中晚期直肠癌临床研究

    Institute of Scientific and Technical Information of China (English)

    王园园; 王义善; 杨柯; 胡蓉蓉; 杨桂青

    2012-01-01

    目的 观察适形调强放射治疗(IMRT)联合热疗治疗中晚期直肠癌的临床疗效.方法 将60例中晚期直肠癌患者随机分为单纯IMRT组及IMRT联合热疗组,分别给予相应治疗,比较2组患者治疗后临床疗效.结果 IMRT联合热疗组的治疗有效率87%,单纯IMRT组63%,2组有效率比较有显著性差异(P<0.05);在ZPS评分改善方面,IMRT联合热疗组也优于单纯IMRT组,且差异具有统计学意义.结论 IMRT联合热疗能够更有效地控制中晚期直肠癌,值得临床推广应用.%Objective It is to observe the clinical effect of intensity-modulated radiation therapy ( IMRT ) combined with thermotherapy in the treatment for advanced rectum cancer. Methods Sixty patients with advanced rectum cancer were randomly divided into IMRT group and IMRT combined with thermotherapy group. After treatment, the differences of clinical effect between these two groups were evaluated. Results The therapeutic effect was 87% in IMRT combined with thermotherapy group, and that was 63% in IMRT group, there was significant difference between both groups ( P <0.05 ). In the aspect of the improvement of ZPS scores, IMRT combined with thermotherapy group was also better than IMRT group only, there was significant difference between both groups ( P <0.05 ). Conclusion IMRT combined with thermotherapy can control advanced rectum cancer better, and thus, it deserves popularize clinical application.

  20. Clinical Implementation of Intensity Modulated Proton Therapy for Thoracic Malignancies

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Joe Y., E-mail: jychang@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Li, Heng; Zhu, X. Ronald [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liao, Zhongxing; Zhao, Lina [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liu, Amy [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Li, Yupeng [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Applied Research, Varian Medical Systems, Palo Alto, California (United States); Sahoo, Narayan; Poenisch, Falk [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Gomez, Daniel R. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wu, Richard; Gillin, Michael [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Zhang, Xiaodong, E-mail: xizhang@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2014-11-15

    Purpose: Intensity modulated proton therapy (IMPT) can improve dose conformality and better spare normal tissue over passive scattering techniques, but range uncertainties complicate its use, particularly for moving targets. We report our early experience with IMPT for thoracic malignancies in terms of motion analysis and management, plan optimization and robustness, and quality assurance. Methods and Materials: Thirty-four consecutive patients with lung/mediastinal cancers received IMPT to a median 66 Gy(relative biological equivalence [RBE]). All patients were able to undergo definitive radiation therapy. IMPT was used when the treating physician judged that IMPT conferred a dosimetric advantage; all patients had minimal tumor motion (<5 mm) and underwent individualized tumor-motion dose-uncertainty analysis and 4-dimensional (4D) computed tomographic (CT)-based treatment simulation and motion analysis. Plan robustness was optimized by using a worst-case scenario method. All patients had 4D CT repeated simulation during treatment. Results: IMPT produced lower mean lung dose (MLD), lung V{sub 5} and V{sub 20}, heart V{sub 40}, and esophageal V{sub 60} than did IMRT (P<.05) and lower MLD, lung V{sub 20}, and esophageal V{sub 60} than did passive scattering proton therapy (PSPT) (P<.05). D{sub 5} to the gross tumor volume and clinical target volume was higher with IMPT than with intensity modulated radiation therapy or PSPT (P<.05). All cases were analyzed for beam-angle-specific motion, water-equivalent thickness, and robustness. Beam angles were chosen to minimize the effect of respiratory motion and avoid previously treated regions, and the maximum deviation from the nominal dose-volume histogram values was kept at <5% for the target dose and met the normal tissue constraints under a worst-case scenario. Patient-specific quality assurance measurements showed that a median 99% (range, 95% to 100%) of the pixels met the 3% dose/3 mm distance criteria for the

  1. Benchmarking Dosimetric Quality Assessment of Prostate Intensity-Modulated Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Senthi, Sashendra, E-mail: sasha.senthi@petermac.org [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Gill, Suki S. [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Haworth, Annette; Kron, Tomas; Cramb, Jim [Department of Physical Sciences, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Rolfo, Aldo [Radiation Therapy Services, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Thomas, Jessica [Biostatistics and Clinical Trials, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Duchesne, Gillian M. [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Hamilton, Christopher H.; Joon, Daryl Lim [Radiation Oncology Department, Austin Repatriation Hospital, Heidelberg, VIC (Australia); Bowden, Patrick [Radiation Oncology Department, Tattersall' s Cancer Center, East Melbourne, VIC (Australia); Foroudi, Farshad [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia)

    2012-02-01

    Purpose: To benchmark the dosimetric quality assessment of prostate intensity-modulated radiotherapy and determine whether the quality is influenced by disease or treatment factors. Patients and Methods: We retrospectively analyzed the data from 155 consecutive men treated radically for prostate cancer using intensity-modulated radiotherapy to 78 Gy between January 2007 and March 2009 across six radiotherapy treatment centers. The plan quality was determined by the measures of coverage, homogeneity, and conformity. Tumor coverage was measured using the planning target volume (PTV) receiving 95% and 100% of the prescribed dose (V{sub 95%} and V{sub 100%}, respectively) and the clinical target volume (CTV) receiving 95% and 100% of the prescribed dose. Homogeneity was measured using the sigma index of the PTV and CTV. Conformity was measured using the lesion coverage factor, healthy tissue conformity index, and the conformity number. Multivariate regression models were created to determine the relationship between these and T stage, risk status, androgen deprivation therapy use, treatment center, planning system, and treatment date. Results: The largest discriminatory measurements of coverage, homogeneity, and conformity were the PTV V{sub 95%}, PTV sigma index, and conformity number. The mean PTV V{sub 95%} was 92.5% (95% confidence interval, 91.3-93.7%). The mean PTV sigma index was 2.10 Gy (95% confidence interval, 1.90-2.20). The mean conformity number was 0.78 (95% confidence interval, 0.76-0.79). The treatment center independently influenced the coverage, homogeneity, and conformity (all p < .0001). The planning system independently influenced homogeneity (p = .038) and conformity (p = .021). The treatment date independently influenced the PTV V{sub 95%} only, with it being better at the start (p = .013). Risk status, T stage, and the use of androgen deprivation therapy did not influence any aspect of plan quality. Conclusion: Our study has benchmarked measures

  2. Prospective evaluation of a hydrogel spacer for rectal separation in dose-escalated intensity-modulated radiotherapy for clinically localized prostate cancer

    Directory of Open Access Journals (Sweden)

    Eckert Franziska

    2013-01-01

    Full Text Available Abstract Background As dose-escalation in prostate cancer radiotherapy improves cure rates, a major concern is rectal toxicity. We prospectively assessed an innovative approach of hydrogel injection between prostate and rectum to reduce the radiation dose to the rectum and thus side effects in dose-escalated prostate radiotherapy. Methods Acute toxicity and planning parameters were prospectively evaluated in patients with T1-2 N0 M0 prostate cancer receiving dose-escalated radiotherapy after injection of a hydrogel spacer. Before and after hydrogel injection, we performed MRI scans for anatomical assessment of rectal separation. Radiotherapy was planned and administered to 78 Gy in 39 fractions. Results From eleven patients scheduled for spacer injection the procedure could be performed in ten. In one patient hydrodissection of the Denonvillier space was not possible. Radiation treatment planning showed low rectal doses despite dose-escalation to the target. In accordance with this, acute rectal toxicity was mild without grade 2 events and there was complete resolution within four to twelve weeks. Conclusions This prospective study suggests that hydrogel injection is feasible and may prevent rectal toxicity in dose-escalated radiotherapy of prostate cancer. Further evaluation is necessary including the definition of patients who might benefit from this approach. Trial registration: German Clinical Trials Register DRKS00003273.

  3. Definitive Reirradiation for Locoregionally Recurrent Non-Small Cell Lung Cancer With Proton Beam Therapy or Intensity Modulated Radiation Therapy: Predictors of High-Grade Toxicity and Survival Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    McAvoy, Sarah; Ciura, Katherine; Wei, Caimiao; Rineer, Justin; Liao, Zhongxing; Chang, Joe Y.; Palmer, Matthew B.; Cox, James D.; Komaki, Ritsuko; Gomez, Daniel R., E-mail: DGomez@mdanderson.org

    2014-11-15

    Purpose: Intrathoracic recurrence of non-small cell lung cancer (NSCLC) after initial treatment remains a dominant cause of death. We report our experience using proton beam therapy and intensity modulated radiation therapy for reirradiation in such cases, focusing on patterns of failure, criteria for patient selection, and predictors of toxicity. Methods and Materials: A total of 102 patients underwent reirradiation for intrathoracic recurrent NSCLC at a single institution. All doses were recalculated to an equivalent dose in 2-Gy fractions (EQD2). All patients had received radiation therapy for NSCLC (median initial dose of 70 EQD2 Gy), with median interval to reirradiation of 17 months and median reirradiation dose of 60.48 EQD2 Gy. Median follow-up time was 6.5 months (range, 0-72 months). Results: Ninety-nine patients (97%) completed reirradiation. Median local failure-free survival, distant metastasis-free survival (DMFS), and overall survival times were 11.43 months (range, 8.6-22.66 months), 11.43 months (range, 6.83-23.84 months), and 14.71 (range, 10.34-20.56 months), respectively. Toxicity was acceptable, with rates of grade ≥3 esophageal toxicity of 7% and grade ≥3 pulmonary toxicity of 10%. Of the patients who developed local failure after reirradiation, 88% had failure in either the original or the reirradiation field. Poor local control was associated with T4 disease, squamous histology, and Eastern Cooperative Oncology Group performance status score >1. Concurrent chemotherapy improved DMFS, but T4 disease was associated with poor DMFS. Higher T status, Eastern Cooperative Oncology Group performance status ≥1, squamous histology, and larger reirradiation target volumes led to worse overall survival; receipt of concurrent chemotherapy and higher EQD2 were associated with improved OS. Conclusions: Intensity modulated radiation therapy and proton beam therapy are options for treating recurrent non-small cell lung cancer. However, rates of

  4. The Current Status of the Delineation and Determination of the Targets and the Radiation Protocols for Nasopharyngeal Cancer with Intensity-Modulated Radiotherapy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    IMRT has increased the local-regional control and decreased the complications from treating nasopharyngeal cancer (NPC).Therefore studying IMRT is important. CT and MRI are complementary, and their joint use is currently considered to be the optimal modality to delineate the extent of the primary spread of NPC. The key problem in delineation of the neck nodes is how to translate anatomic node regions into the CT boundaries. The consensus guideline which narrowed the gap among different cancer centers is recommended in delineating the boundary of the cervical lymph node regions. The definition of the NPC GTV is clear and almost the same among the main cancer centers in their IMRT planning protocols.The suggested biological dose to the GTV is close to or more than 80 Gy;the main differences are the definitions of the CTVs and their schemes for the prescribed dose, and also the dosage to the high cervical region is different among those centers. According to their long-term follow-up results, it is suggested that, besides adding 5~10 mm margins to the primary lesions,the immediate high-risk structures (including the entire nasopharyngeal cavity, retropharyngeal space, clivus, base of the skull, pterygoid plates and muscles, parapharyngeal space, the sphenoid and partial ethmoid sinuses,the posterior third of the maxillary sinuses and the nasal cavity) should also be included with a prescription of more than 60 Gy, and the bilateral Ib, Ⅱ and Ⅴa node levels should be ranked as high-risk regions and differentially prescribed for treatment with no less than 60 Gy.

  5. Image-guided intensity-modulated radiotherapy for refractory bilateral breast cancer in a patient with extensive cutaneous metastasis in the chest and abdominal walls

    Directory of Open Access Journals (Sweden)

    Lu YF

    2016-05-01

    Full Text Available Yueh-Feng Lu,1 Yu-Chin Lin,2 Kuo-Hsin Chen,3,4 Pei-Wei Shueng,1 Hsin-Pei Yeh,1 Chen-Hsi Hsieh1,5,6 1Division of Radiation Oncology, Department of Radiology, 2Division of Oncology and Hematology, Department of Medicine, 3Department of Surgery, Far Eastern Memorial Hospital, New Taipei City, 4Department of Electrical Engineering, Yuan-Ze University, Taoyuan, 5Department of Medicine, 6Institute of Traditional Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan Abstract: Treatment for bilateral breast cancer with chest wall and abdominal skin invasion normally involves conventional radiotherapy (RT; however, conventional RT provides inadequate target volume coverage and excessive treatment of large volumes of normal tissue. Helical tomotherapy (HT has the ability to deliver continuous craniocaudal irradiation that suppresses junction problems and provides good conformity of dose distribution. A 47-year-old female with stage IV bilateral breast cancer with chest wall and pectoralis major muscle invasion, lymphadenopathy, bilateral pleural effusion, and multiple bone metastases received chemotherapy and target therapy beginning in January 2014; 4 months after the initiation of chemotherapy, computed tomography revealed progression of chest and abdominal wall invasion. A total dose of 70.2 Gy was delivered to both breasts, the chest wall, the abdominal wall, and the bilateral supraclavicular nodal areas in 39 fractions via HT. The total planning target volume was 4,533.29 cm3. The percent of lung volume receiving at least 20 Gy (V20 was 28%, 22%, and 25% for the right lung, left lung, and whole lung, respectively. The mean dose to the heart was 8.6 Gy. Follow-up computed tomography revealed complete response after the RT course. Grade 1 dysphagia, weight loss, grade 2 neutropenia, and grade 3 dermatitis were noted during the RT course. Pain score decreased from 6 to 1. No cardiac, pulmonary, liver, or intestinal toxicity

  6. SU-E-T-272: Radiation Damage Comparison Between Intensity Modulated Radiotherapy and Field-In-Field Technique in Breast Cancer Treatments

    Energy Technology Data Exchange (ETDEWEB)

    Ai, H [IU School of Medicine, Indianapolis, IN (United States); Zhang, H [Northwestern Memorial Hospital, Chicago, IL (United States)

    2014-06-01

    Purpose: To compare normal tissue complications between IMRT and FIF treatment in breast cancer. Methods: 16 patients treated with IMRT plan and 20 patients treated with FIF plan were evaluated in this study. Both kinds of plans were generated using Eclipse treatment planning system by dosimetrist following clinical radiotherapy treatment guidelines. The plans were reviewed and approved by radiation oncologist. The average survival fraction (SF) for three different normal tissue cells of each concerned structure can be calculated from differential dose volume histogram (DVH) using linear quadratic model. The three types of normal tissues include radiosensitive, moderately radiosensitive and radio-resistant that represents 70%, 50% and 30% survival fractions, respectively, for a 2-Gy open field. Equivalent uniform doses (EUD) for corresponding normal tissues of each structure were calculated. Results: The EUDs of the lungs, heart, healthy breast and spinal cord with both IMRT and FIF treatments were calculated. Considering the average value of all IMRT plans, the lung of treated side absorbed 16.0% of dosage prescribed to the tumor if the radiosensitivity of the lung is similar to the radiosensitive cell line. For moderately radiosensitive and radio-resistant lung tissue, the average EUDs can be 18.9% and 22.4% of prescription. In contrast, patients treated with FIF plans were delivered 6.0%, 7.5% and 10.3% of prescribed dose for radiosensitive, moderately radiosensitive and radio-resistant lung tissue, respectively. Comparing heart EUDs between IMRT and FIF plans, average absorbed doses in IMRT treatment were 7.7%, 8.7% and 9.7% of prescription for three types of heart normal tissue cell lines while FIF treatments delivered only 1.3%, 1.5% and 1.6% of prescription dose. For the other organs, the results were similar. Conclusion: The results indicated that breast cancer treatment using IMRT technique had more normal tissue damage than FIF treatment. FIF demonstrated

  7. Conventionally-fractionated image-guided intensity modulated radiotherapy (IG-IMRT: a safe and effective treatment for cancer spinal metastasis

    Directory of Open Access Journals (Sweden)

    Jiang Xiaoqin

    2008-04-01

    Full Text Available Abstract Background Treatments for cancer spinal metastasis were always palliative. This study was conducted to investigate the safety and effectiveness of IG-IMRT for these patients. Methods 10 metastatic lesions were treated with conventionally-fractionated IG-IMRT. Daily kilovoltage cone-beam computed tomography (kV-CBCT scan was applied to ensure accurate positioning. Plans were evaluated by the dose-volume histogram (DVH analysis. Results Before set-up correction, the positioning errors in the left-right (LR, superior-inferior (SI and anterior-posterior (AP axes were 0.3 ± 3.2, 0.4 ± 4.5 and -0.2 ± 3.9 mm, respectively. After repositioning, those errors were 0.1 ± 0.7, 0 ± 0.8 and 0 ± 0.7 mm, respectively. The systematic/random uncertainties ranged 1.4–2.3/3.0–4.1 before and 0.1–0.2/0.7–0.8 mm after online set-up correction. In the original IMRT plans, the average dose of the planning target volume (PTV was 61.9 Gy, with the spinal cord dose less than 49 Gy. Compared to the simulated PTVs based on the pre-correction CBCT, the average volume reduction of PTVs was 42.3% after online correction. Also, organ at risk (OAR all benefited from CBCT-based set-up correction and had significant dose reduction with IGRT technique. Clinically, most patients had prompt pain relief within one month of treatment. There was no radiation-induced toxicity detected clinically during a median follow-up of 15.6 months. Conclusion IG-IMRT provides a new approach to treat cancer spinal metastasis. The precise positioning ensures the implementation of optimal IMRT plan, satisfying both the dose escalation of tumor targets and the radiation tolerance of spinal cord. It might benefit the cancer patient with spinal metastasis.

  8. The Comparison of Stereotactic Body Radiation Therapy (SBRT andIntensity Modulated Radiation Therapy (IMRT for prostate cancer byNCCN risk groups

    Directory of Open Access Journals (Sweden)

    Anthony Ricco

    2016-08-01

    Full Text Available OBJECTIVES: The primary objective of this study is to compare freedom from biochemical failure (FFBF between SBRT and IMRT for patients with organ confined prostate cancer treated between 2007 through 2012 utilizing the 2015 National Comprehensive Cancer Network (NCCN risk stratification guidelines. A secondary objective is to compare our updated toxicity at last follow up compared to pretreatment with respect to bowel, bladder, sexual functioning, and need for invasive procedures between the two groups.METHODS: We retrospectively reviewed 270 consecutive men treated with either SBRT (n=150 or IMRT (120 at a community hospital with two distinct radiation departments and referral patterns. Charts were reviewed for pretreatment and treatment factors including race, age, clinical T stage, initial PSA, Gleason score, use of androgen deprivation therapy (ADT, treatment with SBRT vs. IMRT as well as stratification by 2015 NCCN guidelines. Kaplan Meier (KM methodology was used to estimate freedom from biochemical failure, with statistical comparisons accomplished using log rank tests. Multivariable Cox proportional hazard modeling was used to establish independent factors prognostic of biochemical failure. Descriptive statistics were used to describe toxicity graded by a modified RTOG late radiation morbidity scoring system. RESULTS: Significant prognostic factors in univariate analysis for FFBF included NCCN risk groups (p=0.0032, grade (p=0.019, and PSA (p=0.008. There was no significant difference in FFBF between SBRT vs. IMRT (p=0.46 with 6 year actuarial FFBF of 91.9% for SBRT and 88.9% for IMRT. Multivariable analysis revealed only the NCCN risk stratification to be significant predictor for FFBF (p=0.04. 4 year actuarial FFBF by NCCN risk stratification was 100% very low risk, 100% low risk, 96.5% intermediate risk, 94.5% high risk, and 72.7% very high risk. There were no grade 3 gastrointestinal (GI or genitourinary (GU toxicities for either

  9. Dose-Painted Intensity-Modulated Radiation Therapy for Anal Cancer: A Multi-Institutional Report of Acute Toxicity and Response to Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kachnic, Lisa A., E-mail: lisa.kachnic@bmc.org [Department of Radiation Oncology, Boston Medical Center, Boston, MA (United States); Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Tsai, Henry K. [Harvard Radiation Oncology Program, Harvard Medical School, Boston, MA (United States); Coen, John J. [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Blaszkowsky, Lawrence S. [Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Hartshorn, Kevan [Department of Medicine, Boston Medical Center, Boston, MA (United States); Kwak, Eunice L. [Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Willins, John D. [Department of Radiation Oncology, Boston Medical Center, Boston, MA (United States); Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Ryan, David P. [Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Hong, Theodore S. [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States)

    2012-01-01

    Purpose: Chemoradiation for anal cancer yields effective tumor control, but is associated with significant acute toxicity. We report our multi-institutional experience using dose-painted IMRT (DP-IMRT). Patients and Methods: Between August 2005 and May 2009, 43 patients were treated with DP-IMRT and concurrent chemotherapy for biopsy-proven, squamous cell carcinoma of the anal canal at two academic medical centers. DP-IMRT was prescribed as follows: T2N0: 42 Gy, 1.5 Gy/fraction (fx) to elective nodal planning target volume (PTV) and 50.4 Gy, 1.8 Gy/fx to anal tumor PTV; T3-4N0-3: 45 Gy, 1.5 Gy/fx to elective nodal PTV, and 54 Gy, 1.8 Gy/fx to the anal tumor and metastatic nodal PTV >3 cm with 50.4 Gy, 1.68 Gy/fx to nodal PTVs {<=}3 cm in size. Acute and late toxicity was reported by the treating physician. Actuarial analysis was performed using the Kaplan-Meier method. Results: Median age was 58 years; 67% female; 16% Stage I, 37% II; 42% III; 5% IV. Fourteen patients were immunocompromised: 21% HIV-positive and 12% on chronic immunosuppression. Median follow-up was 24 months (range, 0.6-43.5 months). Sixty percent completed chemoradiation without treatment interruption; median duration of treatment interruption was 2 days (range, 2-24 days). Acute Grade 3+ toxicity included: hematologic 51%, dermatologic 10%, gastrointestinal 7%, and genitourinary 7%. Two-year local control, overall survival, colostomy-free survival, and metastasis-free survival were 95%, 94%, 90%, and 92%, respectively. Conclusions: Dose-painted IMRT appears effective and well-tolerated as part of a chemoradiation therapy regimen for the treatment of anal canal cancer.

  10. Using multivariate regression model with least absolute shrinkage and selection operator (LASSO to predict the incidence of Xerostomia after intensity-modulated radiotherapy for head and neck cancer.

    Directory of Open Access Journals (Sweden)

    Tsair-Fwu Lee

    Full Text Available PURPOSE: The aim of this study was to develop a multivariate logistic regression model with least absolute shrinkage and selection operator (LASSO to make valid predictions about the incidence of moderate-to-severe patient-rated xerostomia among head and neck cancer (HNC patients treated with IMRT. METHODS AND MATERIALS: Quality of life questionnaire datasets from 206 patients with HNC were analyzed. The European Organization for Research and Treatment of Cancer QLQ-H&N35 and QLQ-C30 questionnaires were used as the endpoint evaluation. The primary endpoint (grade 3(+ xerostomia was defined as moderate-to-severe xerostomia at 3 (XER3m and 12 months (XER12m after the completion of IMRT. Normal tissue complication probability (NTCP models were developed. The optimal and suboptimal numbers of prognostic factors for a multivariate logistic regression model were determined using the LASSO with bootstrapping technique. Statistical analysis was performed using the scaled Brier score, Nagelkerke R(2, chi-squared test, Omnibus, Hosmer-Lemeshow test, and the AUC. RESULTS: Eight prognostic factors were selected by LASSO for the 3-month time point: Dmean-c, Dmean-i, age, financial status, T stage, AJCC stage, smoking, and education. Nine prognostic factors were selected for the 12-month time point: Dmean-i, education, Dmean-c, smoking, T stage, baseline xerostomia, alcohol abuse, family history, and node classification. In the selection of the suboptimal number of prognostic factors by LASSO, three suboptimal prognostic factors were fine-tuned by Hosmer-Lemeshow test and AUC, i.e., Dmean-c, Dmean-i, and age for the 3-month time point. Five suboptimal prognostic factors were also selected for the 12-month time point, i.e., Dmean-i, education, Dmean-c, smoking, and T stage. The overall performance for both time points of the NTCP model in terms of scaled Brier score, Omnibus, and Nagelkerke R(2 was satisfactory and corresponded well with the expected values

  11. SU-E-T-25: A Dosimetric Comparison of Three-Dimension Conformal and Intensity-Modulated Radiation Therapy in Esophageal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, N; Maneru, F; Fuentemilla, N; Olasolo, J; Gracia, M; Pellejero, S; Bragado, L; Lozares, S; Miquelez, S; Martin, M [Complejo Hospitalario de Navarra, Pamplona, Navarra (Spain)

    2015-06-15

    Purpose: dosimetric comparison of 3DCRT and IMRT in 9 esophageal cancer. The aim of this paper is to know which of these two techniques is dosimetrically more favorable dosimetrically at both the CTV coverage and dose obtained in the relevant organs at risk, in this case, lungs and heart, as the spinal cord received in all cases below 45 Gy. Methods: we chose 9 patients from our center (CHN) with the same type of esophageal cancer and in which the prescribed dose was the same, 54 Gy. For these treatments we have used the same fields and the same angles (AP (0 °), OPD (225°–240°) and OPI (125°–135°)).All plans have been implemented using Eclipse (version 11.0) with AAA( Analytical Anisotropic Algorithm )(Version 11.0.31). Results: To analyze the coverage of the CTV, we have evaluated the D99% and found that the average dose received by 99% of CTV with IMRT is 53.8 ± 0.4 Gy (99.6% of the prescribed dose) and the mean value obtained with 3DCRT is 52.3 ± 0.6 Gy (96.8% of the prescribed dose).The last data analyzed was the D2% of PTV, a fact that gives us information on the maximum dose received by our PTV. D2% of the PTV for IMRT planning is 55.4 ± 0.4 Gy (102.6% of the prescribed dose) and with 3DCRT is 56.8 ± 0.7 Gy (105.2% of the prescribed dose).All parameters analyzed at risk organs (V30, V40, V45 and V50 for the case of heart and V5, V10, V15 and V20 for the case of the lungs) provide us irradiated volume percentages lower in IMRT than 3DCRT. Conclusion: IMRT provides a considerable improvement in the coverage of the CTV and the doses to organs at risk.

  12. Dosimetric consequences of tumor volume changes after kilovoltage cone-beam computed tomography for non-operative lung cancer during adaptive intensity-modulated radiotherapy or fractionated stereotactic radiotherapy

    Institute of Scientific and Technical Information of China (English)

    Jian Hu; Ximing Xu; Guangjin Yuan; Wei Ge; Liming Xu; Aihua Zhang; Junjian Deng

    2015-01-01

    Objective The aim of this study was to investigate tumor volume changes with kilovoltage cone-beam computed tomography (kV-CBCT) and their dosimetric consequences for non-operative lung cancer during intensity-modulated radiotherapy (IMRT) or fractionated stereotactic radiotherapy. Methods Eighteen patients with non-operative lung cancer who received IMRT consisting of 1.8-2.2 Gy/fraction and five fractions per week or stereotactic radiotherapy with 5-8 Gy/fraction and three fractions a week were studied. kV-CBCT was performed once per week during IMRT and at every fraction during stereotactic radiotherapy. The gross tumor volume (GTV) was contoured on the kV-CBCT images, and adaptive treatment plans were created using merged kV-CBCT and primary planning computed tomogra-phy image sets. Tumor volume changes and dosimetric parameters, including the minimum dose to 95%(D95) or 1% (D1) of the planning target volume (PTV), mean lung dose (MLD), and volume of lung tissue that received more than 5 (V5), 10 (V10), 20 (V20), and 30 (V30) Gy were retrospectively analyzed. Results The average maximum change in GTV observed during IMRT or fractionated stereotactic radio-therapy was -25.85% (range, -13.09% --56.76%). The D95 and D1 of PTV for the adaptive treatment plans in all patients were not significantly different from those for the initial or former adaptive treatment plans. In patients with tumor volume changes of >20% in the third or fourth week of treatment during IMRT, adap-tive treatment plans offered clinically meaningful decreases in MLD and V5, V10, V20, and V30; however, in patients with tumor volume changes of 20% in the third or fourth week of treatment.

  13. 调强适形放疗在乳腺癌保乳术后应用的系统评价%Intensity-modulated radiotherapy for breast cancer: a systematic review

    Institute of Scientific and Technical Information of China (English)

    Xiupeng Ye; Liyun Guo; Ruifeng Liu; Shifang Feng; Ling Su; Xiaohu Wang; Kehu Yang; Jinhui Tian; Qiuning Zhang; Qiang Wang; Xiaojun Li; Yuqing Kang

    2010-01-01

    Objective: The aim of this study was to assess the long-term effect of breast conservation with breast intensity-modulated radiotherapy (IMRT) for early-stage breast cancers. Methods: Pub Med, EMBASE, Cochrane Library, Chinese Biomedical Literature Database were searched to identify relevant original published trails, and the references of eligible studies were manually screened. Randomized controlled trails reported in any language, comparing breast IMRT with conventional radiotherapy (RT) in patients with early-stage breast cancer were eligible for inclusion. Two investigators independently assessed the quality of included trials and extracted data. The RevMan 5.0 software was used for statistical analysis. Results: Four trials involving 1440 patients were included. The results showed that in the IMRT group, the occurrence of acute moist dermatitis, the edema of the mammary gland and the occurrence of hyperpigmentation were lower than those of RT group, the pooled risk ratio value and 95% confidence interval were 0.28 (0.17-0.48), 0.03 (0.00-0.21) and 0.06 (0.02-0.15) respectively. The use of IMRT did not correlate with pain and quality of life, but the presence of moist desquamation did significantly correlate with pain and reduced quality of life. Conclusion: The currently available evidence showed that IMRT significantly reduces the occurrence of moist acute dermatitis anywhere in the breast and alleviates the suffering of patients and improves the quality of life of patients. Future large-scale, high-quality, double-blind trials are needed.

  14. Intensity modulated short circuit current spectroscopy for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kavasoglu, Nese; Sertap Kavasoglu, A.; Birgi, Ozcan; Oktik, Sener [Mugla University, Faculty of Arts and Sciences, Physics Department, TR-48000 Mugla (Turkey); Mugla University Clean Energy Research and Development Centre, TR-48000 Mugla (Turkey)

    2011-02-15

    Understanding charge separation and transport is momentously important for the rectification of solar cell performance. To probe photo-generated carrier dynamics, we implemented intensity modulated short circuit current spectroscopy (IMSCCS) on porous Si and Cu(In{sub x},Ga{sub 1-x})Se{sub 2} solar cells. In this experiment, the solar cells were lightened with sinusoidally modulated monochromatic light. The photocurrent response of the solar cell as a function of modulation frequency is measured as the optoelectronic transfer function of the system. The optoelectronic transfer function introduces the connection between the modulated light intensity and measured AC current of the solar cell. In this study, interaction of free carriers with the density of states of the porous Si and Cu(In{sub x}, Ga{sub 1-x})Se{sub 2} solar cells was studied on the basis of charge transport time by IMSCCS data. (author)

  15. Cone beam computed tomography: An accurate imaging technique in comparison with orthogonal portal imaging in intensity-modulated radiotherapy for prostate cancer

    Directory of Open Access Journals (Sweden)

    Om Prakash Gurjar

    2016-03-01

    Full Text Available Purpose: Various factors cause geometric uncertainties during prostate radiotherapy, including interfractional and intrafractional patient motions, organ motion, and daily setup errors. This may lead to increased normal tissue complications when a high dose to the prostate is administered. More-accurate treatment delivery is possible with daily imaging and localization of the prostate. This study aims to measure the shift of the prostate by using kilovoltage (kV cone beam computed tomography (CBCT after position verification by kV orthogonal portal imaging (OPI.Methods: Position verification in 10 patients with prostate cancer was performed by using OPI followed by CBCT before treatment delivery in 25 sessions per patient. In each session, OPI was performed by using an on-board imaging (OBI system and pelvic bone-to-pelvic bone matching was performed. After applying the noted shift by using OPI, CBCT was performed by using the OBI system and prostate-to-prostate matching was performed. The isocenter shifts along all three translational directions in both techniques were combined into a three-dimensional (3-D iso-displacement vector (IDV.Results: The mean (SD IDV (in centimeters calculated during the 250 imaging sessions was 0.931 (0.598, median 0.825 for OPI and 0.515 (336, median 0.43 for CBCT, p-value was less than 0.0001 which shows extremely statistical significant difference.Conclusion: Even after bone-to-bone matching by using OPI, a significant shift in prostate was observed on CBCT. This study concludes that imaging with CBCT provides a more accurate prostate localization than the OPI technique. Hence, CBCT should be chosen as the preferred imaging technique.

  16. Interfraction rotation of the prostate as evaluated by kilovoltage X-ray fiducial marker imaging in intensity-modulated radiotherapy of localized prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Graf, Reinhold; Boehmer, Dirk; Budach, Volker [Charite Universitaetsmedizin Berlin, Department of Radiation Oncology, Campus Virchow-Klinikum, Berlin (Germany); Wust, Peter, E-mail: peter.wust@charite.de [Charite Universitaetsmedizin Berlin, Department of Radiation Oncology, Campus Virchow-Klinikum, Berlin (Germany)

    2012-01-01

    To quantify the daily rotation of the prostate during a radiotherapy course using stereoscopic kilovoltage (kV) x-ray imaging and intraprostatic fiducials for localization and positioning correction. From 2005 to 2009, radio-opaque fiducial markers were inserted into 38 patients via perineum into the prostate. The ExacTrac/Novalis Body X-ray 6-day image acquisition system (ET/NB; BrainLab AG, Feldkirchen, Germany) was used to determine and correct the target position. During the first period in 10 patients we recorded all rotation errors but used only Y (table) for correction. For the next 28 patients we used for correction all rotational coordinates, i.e., in addition Z (superior-inferior [SI] or roll) and X (left-right [LR] or tilt/pitch) according to the fiducial marker position by use of the Robotic Tilt Module and Varian Exact Couch. Rotation correction was applied above a threshold of 1 Degree-Sign displacement. The systematic and random errors were specified. Overall, 993 software-assisted rotational corrections were performed. The interfraction rotation errors of the prostate as assessed from the radiodense surrogate markers around the three axes Y, Z, and X were on average 0.09, -0.52, and -0.01 Degree-Sign with standard deviations of 2.01, 2.30, and 3.95 Degree-Sign , respectively. The systematic uncertainty per patient for prostate rotation was estimated with 2.30, 1.56, and 4.13 Degree-Sign and the mean random components with 1.81, 2.02, and 3.09 Degree-Sign . The largest rotational errors occurred around the X-axis (pitch), but without preferring a certain orientation. Although the error around Z (roll) can be compensated on average by a transformation with 4 coordinates, a significant error around X remains and advocates the full correction with 6 coordinates. Rotational errors as assessed via daily stereoscopic online imaging are significant and dominate around X. Rotation possibly degrades the dosimetric coverage of the target volume and may require

  17. SU-E-T-125: Dosimetric Comparison of Intensity Modulated Radiation Therapy Using Robotic Versus Traditional Linac Platform in Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, T; Rella, J [Alliance Oncology, Newburyport, MA (United States); Yang, J [Alliance Oncology, Newburyport, MA (United States); Drexel University, Philadelphia, PA (United States); Sims, C [Accuray Inc., Sunnyvale, CA (United States); Fung, C [Commonwealth Hematology Oncology, Newburyport, MA (United States)

    2014-06-01

    Purpose: Recent development of an MLC for robotic external beam radiotherapy has the potential of new clinical application in conventionally fractionated radiation therapy. This study offers a dosimetric comparison of IMRT plans using Cyberknife with MLC versus conventional linac plans. Methods: Ten prostate cancer patients treated on a traditional linac with IMRT to 7920cGy at 180cGy/fraction were randomly selected. GTVs were defined as prostate plus proximal seminal vesicles. PTVs were defined as GTV+8mm in all directions except 5mm posteriorly. Conventional IMRT planning was performed on Philips Pinnacle and delivered on a standard linac with CBCT and 10mm collimator leaf width. For each case a Cyberknife plan was created using Accuray Multiplan with same CT data set, contours, and dose constraints. All dosimetric data was transferred to third party software for independent computation of contour volumes and DVH. Delivery efficiency was evaluated using total MU, treatment time, number of beams, and number of segments. Results: Evaluation criteria including percent target coverage, homogeneity index, and conformity index were found to be comparable. All dose constraints from QUANTEC were found to be statistically similar except rectum V50Gy and bladder V65Gy. Average rectum V50Gy was lower for robotic IMRT (30.07%±6.57) versus traditional (34.73%±3.62, p=0.0130). Average bladder V65Gy was lower for robotic (17.87%±12.74) versus traditional (21.03%±11.93, p=0.0405). Linac plans utilized 9 coplanar beams, 48.9±3.8 segments, and 19381±2399MU. Robotic plans utilized 38.4±9.0 non-coplanar beams, 85.5±21.0 segments and 42554.71±16381.54 MU. The average treatment was 15.02±0.60 minutes for traditional versus 20.90±2.51 for robotic. Conclusion: The robotic IMRT plans were comparable to the traditional IMRT plans in meeting the target volume dose objectives. Critical structure dose constraints were largely comparable although statistically significant

  18. Individualized Nonadaptive and Online-Adaptive Intensity-Modulated Radiotherapy Treatment Strategies for Cervical Cancer Patients Based on Pretreatment Acquired Variable Bladder Filling Computed Tomography Scans

    Energy Technology Data Exchange (ETDEWEB)

    Bondar, M.L., E-mail: m.bondar@erasmusmc.nl [Department of Radiation Oncology, Erasmus-MC Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Hoogeman, M.S.; Mens, J.W.; Quint, S. [Department of Radiation Oncology, Erasmus-MC Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Ahmad, R. [Department of Radiation Oncology, Erasmus-MC Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Programme of Diagnostic Imaging and Radiotherapy, University Kebangsaan Malaysia (Malaysia); Dhawtal, G.; Heijmen, B.J. [Department of Radiation Oncology, Erasmus-MC Daniel den Hoed Cancer Center, Rotterdam (Netherlands)

    2012-08-01

    Purpose: To design and evaluate individualized nonadaptive and online-adaptive strategies based on a pretreatment established motion model for the highly deformable target volume in cervical cancer patients. Methods and Materials: For 14 patients, nine to ten variable bladder filling computed tomography (CT) scans were acquired at pretreatment and after 40 Gy. Individualized model-based internal target volumes (mbITVs) accounting for the cervix and uterus motion due to bladder volume changes were generated by using a motion-model constructed from two pretreatment CT scans (full and empty bladder). Two individualized strategies were designed: a nonadaptive strategy, using an mbITV accounting for the full-range of bladder volume changes throughout the treatment; and an online-adaptive strategy, using mbITVs of bladder volume subranges to construct a library of plans. The latter adapts the treatment online by selecting the plan-of-the-day from the library based on the measured bladder volume. The individualized strategies were evaluated by the seven to eight CT scans not used for mbITVs construction, and compared with a population-based approach. Geometric uniform margins around planning cervix-uterus and mbITVs were determined to ensure adequate coverage. For each strategy, the percentage of the cervix-uterus, bladder, and rectum volumes inside the planning target volume (PTV), and the clinical target volume (CTV)-to-PTV volume (volume difference between PTV and CTV) were calculated. Results: The margin for the population-based approach was 38 mm and for the individualized strategies was 7 to 10 mm. Compared with the population-based approach, the individualized nonadaptive strategy decreased the CTV-to-PTV volume by 48% {+-} 6% and the percentage of bladder and rectum inside the PTV by 5% to 45% and 26% to 74% (p < 0.001), respectively. Replacing the individualized nonadaptive strategy by an online-adaptive, two-plan library further decreased the percentage of

  19. A Phase I/II Trial of Intensity Modulated Radiation (IMRT) Dose Escalation With Concurrent Fixed-dose Rate Gemcitabine (FDR-G) in Patients With Unresectable Pancreatic Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Josef, Edgar, E-mail: edgar.ben-josef@uphs.upenn.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Schipper, Mathew [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Francis, Isaac R. [Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Hadley, Scott; Ten-Haken, Randall; Lawrence, Theodore; Normolle, Daniel [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Simeone, Diane M.; Sonnenday, Christopher [Department of Surgery, University of Michigan, Ann Arbor, Michigan (United States); Abrams, Ross [Department of Radiation Oncology, Rush Medical Center, Chicago, Illinois (United States); Leslie, William [Division of Hematology Oncology, Department of Internal Medicine, Rush Medical Center, Chicago, Illinois (United States); Khan, Gazala; Zalupski, Mark M. [Division of Hematology Oncology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan (United States)

    2012-12-01

    Purpose: Local failure in unresectable pancreatic cancer may contribute to death. We hypothesized that intensification of local therapy would improve local control and survival. The objectives were to determine the maximum tolerated radiation dose delivered by intensity modulated radiation with fixed-dose rate gemcitabine (FDR-G), freedom from local progression (FFLP), and overall survival (OS). Methods and Materials: Eligibility included pathologic confirmation of adenocarcinoma, radiographically unresectable, performance status of 0-2, absolute neutrophil count of {>=}1500/mm{sup 3}, platelets {>=}100,000/mm{sup 3}, creatinine <2 mg/dL, bilirubin <3 mg/dL, and alanine aminotransferase/aspartate aminotransferase {<=}2.5 Multiplication-Sign upper limit of normal. FDR-G (1000 mg/m{sup 2}/100 min intravenously) was given on days -22 and -15, 1, 8, 22, and 29. Intensity modulated radiation started on day 1. Dose levels were escalated from 50-60 Gy in 25 fractions. Dose-limiting toxicity was defined as gastrointestinal toxicity grade (G) {>=}3, neutropenic fever, or deterioration in performance status to {>=}3 between day 1 and 126. Dose level was assigned using TITE-CRM (Time-to-Event Continual Reassessment Method) with the target dose-limiting toxicity (DLT) rate set to 0.25. Results: Fifty patients were accrued. DLTs were observed in 11 patients: G3/4 anorexia, nausea, vomiting, and/or dehydration (7); duodenal bleed (3); duodenal perforation (1). The recommended dose is 55 Gy, producing a probability of DLT of 0.24. The 2-year FFLP is 59% (95% confidence interval [CI]: 32-79). Median and 2-year overall survival are 14.8 months (95% CI: 12.6-22.2) and 30% (95% CI 17-45). Twelve patients underwent resection (10 R0, 2 R1) and survived a median of 32 months. Conclusions: High-dose radiation therapy with concurrent FDR-G can be delivered safely. The encouraging efficacy data suggest that outcome may be improved in unresectable patients through intensification of local

  20. Preliminary Toxicity Analysis of 3-Dimensional Conformal Radiation Therapy Versus Intensity Modulated Radiation Therapy on the High-Dose Arm of the Radiation Therapy Oncology Group 0126 Prostate Cancer Trial

    Energy Technology Data Exchange (ETDEWEB)

    Michalski, Jeff M., E-mail: jmichalski@radonc.wustl.edu [Department of Radiation Oncology Washington University Medical Center, St. Louis, Missouri (United States); Yan, Yan [Radiation Therapy Oncology Group Statistical Center, Philadelphia, Pennsylvania (United States); Watkins-Bruner, Deborah [Emory University School of Nursing, Atlanta, Georgia (United States); Bosch, Walter R. [Department of Radiation Oncology Washington University Medical Center, St. Louis, Missouri (United States); Winter, Kathryn [Radiation Therapy Oncology Group Statistical Center, Philadelphia, Pennsylvania (United States); Galvin, James M. [Department of Radiation Oncology Thomas Jefferson University Hospital, Philadelphia, Pennsylvania (United States); Bahary, Jean-Paul [Department of Radiation Oncology Centre Hospitalier de l' Université de Montréal-Notre Dame, Montreal, QC (Canada); Morton, Gerard C. [Department of Radiation Oncology Toronto-Sunnybrook Regional Cancer Centre, Toronto, ON (Canada); Parliament, Matthew B. [Department of Oncology Cross Cancer Institute, Edmonton, AB (Canada); Sandler, Howard M. [Department of Radiation Oncology Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, California (United States)

    2013-12-01

    Purpose: To give a preliminary report of clinical and treatment factors associated with toxicity in men receiving high-dose radiation therapy (RT) on a phase 3 dose-escalation trial. Methods and Materials: The trial was initiated with 3-dimensional conformal RT (3D-CRT) and amended after 1 year to allow intensity modulated RT (IMRT). Patients treated with 3D-CRT received 55.8 Gy to a planning target volume that included the prostate and seminal vesicles, then 23.4 Gy to prostate only. The IMRT patients were treated to the prostate and proximal seminal vesicles to 79.2 Gy. Common Toxicity Criteria, version 2.0, and Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer late morbidity scores were used for acute and late effects. Results: Of 763 patients randomized to the 79.2-Gy arm of Radiation Therapy Oncology Group 0126 protocol, 748 were eligible and evaluable: 491 and 257 were treated with 3D-CRT and IMRT, respectively. For both bladder and rectum, the volumes receiving 65, 70, and 75 Gy were significantly lower with IMRT (all P<.0001). For grade (G) 2+ acute gastrointestinal/genitourinary (GI/GU) toxicity, both univariate and multivariate analyses showed a statistically significant decrease in G2+ acute collective GI/GU toxicity for IMRT. There were no significant differences with 3D-CRT or IMRT for acute or late G2+ or 3+ GU toxicities. Univariate analysis showed a statistically significant decrease in late G2+ GI toxicity for IMRT (P=.039). On multivariate analysis, IMRT showed a 26% reduction in G2+ late GI toxicity (P=.099). Acute G2+ toxicity was associated with late G3+ toxicity (P=.005). With dose–volume histogram data in the multivariate analysis, RT modality was not significant, whereas white race (P=.001) and rectal V70 ≥15% were associated with G2+ rectal toxicity (P=.034). Conclusions: Intensity modulated RT is associated with a significant reduction in acute G2+ GI/GU toxicity. There is a trend for a

  1. Light induced modulation instability of surfaces under intense illumination

    KAUST Repository

    Burlakov, V. M.

    2013-12-17

    We show that a flat surface of a polymer in rubber state illuminated with intense electromagnetic radiation is unstable with respect to periodic modulation. Initial periodic perturbation is amplified due to periodic thermal expansion of the material heated by radiation. Periodic heating is due to focusing-defocusing effects caused by the initial surface modulation. The surface modulation has a period longer than the excitation wavelength and does not require coherent light source. Therefore, it is not related to the well-known laser induced periodic structures on polymer surfaces but may contribute to their formation and to other phenomena of light-matter interaction.

  2. Extended Field Intensity Modulated Radiation Therapy With Concomitant Boost for Lymph Node–Positive Cervical Cancer: Analysis of Regional Control and Recurrence Patterns in the Positron Emission Tomography/Computed Tomography Era

    Energy Technology Data Exchange (ETDEWEB)

    Vargo, John A.; Kim, Hayeon; Choi, Serah [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania (United States); Sukumvanich, Paniti; Olawaiye, Alexander B.; Kelley, Joseph L.; Edwards, Robert P.; Comerci, John T. [Department of Gynecologic Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania (United States); Beriwal, Sushil, E-mail: beriwals@upmc.edu [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania (United States)

    2014-12-01

    Purpose: Positron emission tomography/computed tomography (PET/CT) is commonly used for nodal staging in locally advanced cervical cancer; however the false negative rate for para-aortic disease are 20% to 25% in PET-positive pelvic nodal disease. Unless surgically staged, pelvis-only treatment may undertreat para-aortic disease. We have treated patients with PET-positive nodes with extended field intensity modulated radiation therapy (IMRT) to address the para-aortic region prophylactically with concomitant boost to involved nodes. The purpose of this study was to assess regional control rates and recurrence patterns. Methods and Materials: Sixty-one patients with cervical cancer (stage IBI-IVA) diagnosed from 2003 to 2012 with PET-avid pelvic nodes treated with extended field IMRT (45 Gy in 25 fractions with concomitant boost to involved nodes to a median of 55 Gy in 25 fractions) with concurrent cisplatin and brachytherapy were retrospectively analyzed. The nodal location was pelvis-only in 41 patients (67%) and pelvis + para-aortic in 20 patients (33%). There were a total of 179 nodes, with a median number of positive nodes of 2 (range, 1-16 nodes) per patient and a median nodal size of 1.8 cm (range, 0.7-4.5 cm). Response was assessed by PET/CT at 12 to 16 weeks. Results: Complete clinical and imaging response at the first follow-up visit was seen in 77% of patients. At a mean follow-up time of 29 months (range, 3-116 months), 8 patients experienced recurrence. The sites of persistent/recurrent disease were as follows: cervix 10 (16.3%), regional nodes 3 (4.9%), and distant 14 (23%). The rate of para-aortic failure in patients with pelvic-only nodes was 2.5%. There were no significant differences in recurrence patterns by the number/location of nodes, largest node size, or maximum node standardized uptake value. The rate of late grade 3+ adverse events was 4%. Conclusions: Extended field IMRT was well tolerated and resulted in low regional recurrence

  3. NRG Oncology Radiation Therapy Oncology Group 0822: A Phase 2 Study of Preoperative Chemoradiation Therapy Using Intensity Modulated Radiation Therapy in Combination With Capecitabine and Oxaliplatin for Patients With Locally Advanced Rectal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Theodore S., E-mail: tshong1@mgh.harvard.edu [Massachusetts General Hospital, Boston, Massachusetts (United States); Moughan, Jennifer [NRG Oncology Statistics and Data Management Center, Philadelphia, Pennsylvania (United States); Garofalo, Michael C. [University of Maryland School of Medicine, Baltimore, Maryland (United States); Bendell, Johanna [Sarah Cannon Research Institute, Nashville, Tennessee (United States); Berger, Adam C. [Thomas Jefferson University Hospital, Philadelphia, Pennsylvania (United States); Oldenburg, Nicklas B.E. [North Main Radiation Oncology, Providence, Rhode Island (United States); Anne, Pramila Rani [Thomas Jefferson University Hospital, Philadelphia, Pennsylvania (United States); Perera, Francisco [London Regional Cancer Program/Western Ontario, London, Ontario (Canada); Lee, R. Jeffrey [Intermountain Medical Center, Salt Lake City, Utah (United States); Jabbour, Salma K. [Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey (United States); Nowlan, Adam [Piedmont Hospital, Atlanta, Georgia (United States); DeNittis, Albert [Main Line Community Clinical Oncology Program, Wynnewood, Pennsylvania (United States); Crane, Christopher [University of Texas-MD Anderson Cancer Center, Houston, Texas (United States)

    2015-09-01

    Purpose: To evaluate the rate of gastrointestinal (GI) toxicity of neoadjuvant chemoradiation with capecitabine, oxaliplatin, and intensity modulated radiation therapy (IMRT) in cT3-4 rectal cancer. Methods and Materials: Patients with localized, nonmetastatic T3 or T4 rectal cancer <12 cm from the anal verge were enrolled in a prospective, multi-institutional, single-arm study of preoperative chemoradiation. Patients received 45 Gy with IMRT in 25 fractions, followed by a 3-dimensional conformal boost of 5.4 Gy in 3 fractions with concurrent capecitabine/oxaliplatin (CAPOX). Surgery was performed 4 to 8 weeks after the completion of therapy. Patients were recommended to receive FOLFOX chemotherapy after surgery. The primary endpoint of the study was acute grade 2 to 5 GI toxicity. Seventy-one patients provided 80% probability to detect at least a 12% reduction in the specified GI toxicity with the treatment of CAPOX and IMRT, at a significance level of .10 (1-sided). Results: Seventy-nine patients were accrued, of whom 68 were evaluable. Sixty-one patients (89.7%) had cT3 disease, and 37 (54.4%) had cN (+) disease. Postoperative chemotherapy was given to 42 of 68 patients. Fifty-eight patients had target contours drawn per protocol, 5 patients with acceptable variation, and 5 patients with unacceptable variations. Thirty-five patients (51.5%) experienced grade ≥2 GI toxicity, 12 patients (17.6%) experienced grade 3 or 4 diarrhea, and pCR was achieved in 10 patients (14.7%). With a median follow-up time of 3.98 years, the 4-year rate of locoregional failure was 7.4% (95% confidence interval [CI]: 1.0%-13.7%). The 4-year rates of OS and DFS were 82.9% (95% CI: 70.1%-90.6%) and 60.6% (95% CI: 47.5%-71.4%), respectively. Conclusion: The use of IMRT in neoadjuvant chemoradiation for rectal cancer did not reduce the rate of GI toxicity.

  4. SU-E-T-79: A Study of the Effect of Clinical Tumor Volume Displacement On the Dosage of Post Modified Radical Mastectomy Intensity-Modulated Radiation Therapy Plans for Left-Sided Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W; Ma, C; Li, D; Wu, F [Cancer Hospital of Shantou University Medical College, Shantou, Guangdong (China)

    2015-06-15

    Purpose: To explore the effect of clinical tumor volume (CTV) displacement on the dosage of intensity-modulated radiation therapy (IMRT) plans for left-sided breast cancer after modified radical mastectomy. Methods: We created 2 sets of IMRT plans based on PTV0.5 and PTV0.7 (with CTV displacement of 0.5cm and 0.7cm respectively) for each of the ten consecutive left-sided breast cancer patients after modified radical mastectomy, and compared the difference in PTV coverage and organ at risk (OAR) sparing between the two groups. And then, we compared the difference in PTV coverage in IMRT plans based on PTV0.5 between the group with properly estimated CTV displacement (presuming the actual CTV displacement was 0.5cm) and the one with underestimated CTV displacement (presuming the actual CTV displacement was 0.7cm). The difference in results between the corresponding two groups was compared using paired-sample t-test. P values less than 0.05 were considered statistically significant. Results: IMRT plans derived from PTV0.5 had more homogenous PTV coverage, and less heart, left lung, right breast, right lung, left humeral head and B-P radiation exposure, as well as less total Mu as compared with the ones stemmed from PTV0.7 (all p<0.05). IMRT plans with appropriate estimation of CTV displacement had better PTV coverage compared with the ones with underestimated CTV displacement (all p<0.01). Conclusion: The IMRT plans with smaller CTV displacement in post modified radical mastectomy radiotherapy for left-sided breast cancer has dosimetrical advantages over the ones with larger CTV displacement. Underestimation of CTV displacement can lead to significant reduction of PTV coverage. Individually quantifying and minimizing CTV displacement can significantly improve PTV coverage and OAR (including heart and left lung) sparing. This work was supported by the Medical Scientific Research Foundation of Guangdong Procvince (A2014455 to Changchun Ma)

  5. SU-E-T-409: Intensity Modulated Robotic Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, B; Jin, L; Li, J; Chen, L; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States); Fan, J [Fox Chase Cancer Center, Philadelphia, PA (United States); Virtua Fox Chase Cancer Center, Voorhees, NJ (United States); Zhang, C [Fox Chase Cancer Center, Philadelphia, PA (United States); Qiqihar Medical University, Qiqihar (China)

    2014-06-01

    Purpose: As compared with the IRIS-based models, the MLC-based CyberKnife system allows more efficient treatment delivery due to its improved coverage of large lesions and intensity modulation. The treatment delivery efficiency is mainly determined by the number of selected nodes. This study aimed to demonstrate that relatively small sets of optimally selected nodes could produce high-quality plans. Methods: The full body path of the CyberKnife system consists of 110 nodes, from which we selected various sets for 4 prostate cancer cases using our in-house beamselection software. With the selected nodes we generated IMRT plans using our in-house beamlet-based inverse-planning optimization program. We also produced IMRT plans using the MultiPlan treatment planning system (version 5.0) for the same cases. Furthermore, the nodes selected by MultiPlan were used to produce plans with our own optimization software so that we could compare the quality of the selected sets of nodes. Results: Our beam-selection program selected one node-set for each case, with the number of nodes ranging from 23 to 34. The IMRT plans based on the selected nodes and our in-house optimization program showed adequate target coverage, with favorable critical structure sparing for the cases investigated. Compared with the plans using the nodes selected by MultiPlan, the plans generated with our selected beams provided superior rectum/bladder sparing for 75% of the cases. The plans produced by MultiPlan with various numbers of nodes also suggested that the plan quality was not compromised significantly when the number of nodes was reduced. Conclusion: Our preliminary results showed that with beamletbased planning optimization, one could produce high-quality plans with an optimal set of nodes for MLC-based robotic radiotherapy. Furthermore, our beam-selection strategy could help further improve critical structure sparing.

  6. Plasma-based polarization modulator for high-intensity lasers

    Science.gov (United States)

    Chen, Zi-Yu; Pukhov, Alexander

    2016-12-01

    Manipulation of laser pulses at high intensities is an important yet challenging issue. New types of plasma-based optical devices are promising alternatives to achieve this goal. Here we propose to modulate the polarization state of intense lasers based on oblique reflection from solid-plasma surfaces. A new analytical description is presented considering the plasma as an uniaxial medium that causes birefringence effect. Particle-in-cell simulation results numerically demonstrate that such a scheme can provide a tunable polarization control of the laser pulses even in the relativistic regime. The results are thus relevant for the design of compact, easy to use, and versatile polarization modulators for high-intensity laser pulses.

  7. 宫颈癌术后盆腔容积调强弧形治疗与固定野调强放疗计划的剂量学研究%Dosimetric study of volumetric intensity-modulated arc therapy and fixed field intensity-modulated radiotherapy for cervix cancer

    Institute of Scientific and Technical Information of China (English)

    杨波; 庞廷田; 孙显松; 胡克; 邱杰; 张福泉

    2012-01-01

    Objective To compare the dosimetry characteristics of volumetric intensity-modulated arc therapy (VIMAT) and fixed field intensity-modulated radiation therapy (FF-IMRT) for cervix cancer.Methods CT images of 13 patients with cervix uteri cancer were transferred into Eclipse planning system.FF-IMRT and VIMAT plans were optimized on an Eclipse treatment planning system using beam data generated for Varian trilogy linear accelerator.Planning target volume (PTV) and organs at risk were evaluated with dose-volume histogram.To appraise the difference between the techniques,the paired t-test was applied.Results Compared with the FF-IMRT plans,PTV95% coverage of VIMAT plan group increased (t =9.84,P =0.000),PTV110% became lower (t =-3.72,P =0.003),Dmax decreased (t =-3.51,P=0.005),and CI became worser (t=5.39,P=0.000).PTV105%,Dmean,and HI had no difference (t =-0.02,-0.60,1.13,P =0.842,0.560,0.283).V30 of the bladder was reduced by about 10% (t =-4.99,P =0.000),and Dmean and Dmax were 1.4 Gy and 1.5 Gy lower respectively (t =-3.65,-18.03,P =0.004,0.000) ;V40 of the rectum was reduced by about 10% (t =-2.99,P =0.012),and Dmean and Dmax were reduced by 0.6 Gy,0.8 Gy respectively (t =-2.98,-4.05,P =0.013,0.002) ;V30,V40 and V50 of the small intestine were reduced by 16%,10% and 11% (t =-10.85,-4.74,-8.66,P =0.000,0.001,0.000),and Dmax was reduced by 0.8 Gy (t =-9.45,P =0.000) ; V30,V40 and V50 of the bone marrow were reduced by 26%,19% and 16% (t =-22.10,-10.19,-4.04,P =0.000,0.000,0.002),and Dmean reduced by 1.9 Gy (t =-16.21,P =0.000) ; D5 of the left and right femoral heads were reduced by 1.6 Gy and 2.7 Gy (t =-2.89,-6.22,P =0.015,0.000).Dmax of the caudate equine was reduced by 1.5 Gy (t=-4.80,P=0.001).V20,V30,V40 and V50 of the body were reduced by 18%,18%,4% and3%(t=-7.52,-11.75,-6.26,-6.94,P=0.000,0.000,0.000,0.000).Dmean and Dmax of the body decreased by 1.0 Gy and 0.4 Gy (t=-3.72,-3.51,P=0.000,0.005).Average machine unit (MU) decreased

  8. 利用锥形束CT分析宫颈癌调强适形放疗摆位误差%Setup Errors Analysis with Cone Beam CT for Uterine Cervix Cancer Treated by Intensity Modulated Radiotherapy

    Institute of Scientific and Technical Information of China (English)

    陈鑑; 郭和锋; 林浩; 王国喜

    2013-01-01

    目的:利用锥形束CT(Cone-Beam Computed Tomography,CBCT)影像技术研究本院宫颈癌调强放射治疗(Intensity Modulated Radiation Therapy,IMRT)中的摆位误差,并计算出计划靶区(Planning Target Volume,PTV)的外扩边界范围。方法应用瓦里安TrueBeam放射治疗系统治疗宫颈癌64例,CBCT扫描1次/w,将CBCT图像和原计划CT图像进行匹配得出X、Y、Z轴方向的线性摆位误差,分析误差及其分布规律,推算出 CTV(Clinical Target Volume,CTV)到 PTV的外放边界值。结果得出在X、Y、Z轴方向上的系统误差±随机误差分别为(2.13±1.70)、(2.39±1.99)、(2.50±1.89)mm,推算出本院宫颈癌出 X,Y,Z轴 CTV到 PTV的Margin分别为6.5mm,7.4mm,7.6mm。结论通过CBCT测量摆位误差并进行调整可提高患者摆位精度,为外扩 CTV边界提供了理论依据,使治疗计划的实施更精确。%Objective:The purpose of his work was to invest the setup errors in Intensity modulated radiotherapy for uterine cervix cancer by cone-beam CT (Cone Beam Computerized Tomography, CBCT)imaging technology, and to calculate the safety margins of planning target volume (PTV). Methods:64 patients were treated with Varian TrueBeam system.Al patients had received CBCT once a week.The acquired CBCT images were compared with planning CT images. The errors on X,Y,Z axes were analyzed and the PTV margin was calculated. Results:The average setup error (∑±σ)in X-axis, Y-axis, and Z-axis directions were (2.13±1.70)mm,( 2.39±1.99)mm, (2.50 ±1.89)mm, and the margin of PTV of uterine cervix cancer in three directions (X,Y,Z)was 6.5mm,7.4mm,7.6mm respectively. Conclusions:Measurement of setup error delivery using CBCT scan combined with on-line correction could improve the patient setup precision and may make our design of radiotherapy system more scientific and normal.

  9. Computed Tomography–Guided Interstitial High-Dose-Rate Brachytherapy in Combination With Regional Positive Lymph Node Intensity-Modulated Radiation Therapy in Locally Advanced Peripheral Non–Small Cell Lung Cancer: A Phase 1 Clinical Trial

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Li; Zhang, Jian-wen; Lin, Sheng; Luo, Hui-Qun; Wen, Qing-Lian; He, Li-Jia; Shang, Chang-Ling; Ren, Pei-Rong; Yang, Hong-Ru; Pang, Hao-Wen; Yang, Bo; He, Huai-Lin [Department of Oncology, Affiliated Hospital of Luzhou Medical College, Luzhou (China); Chen, Yue, E-mail: chenyue5523@126.com [Department of Nuclear Medicine, Affiliated Hospital of Luzhou Medical College, Luzhou (China); Wu, Jing-Bo, E-mail: wjb6147@163.com [Department of Oncology, Affiliated Hospital of Luzhou Medical College, Luzhou (China)

    2015-08-01

    Purpose: To assess the technical safety, adverse events, and efficacy of computed tomography (CT)-guided interstitial high-dose-rate (HDR) brachytherapy in combination with regional positive lymph node intensity modulated radiation therapy in patients with locally advanced peripheral non–small cell lung cancer (NSCLC). Methods and Materials: Twenty-six patients with histologically confirmed NSCLC were enrolled in a prospective, officially approved phase 1 trial. Primary tumors were treated with HDR brachytherapy. A single 30-Gy dose was delivered to the 90% isodose line of the gross lung tumor volume. A total dose of at least 70 Gy was administered to the 95% isodose line of the planning target volume of malignant lymph nodes using 6-MV X-rays. The patients received concurrent or sequential chemotherapy. We assessed treatment efficacy, adverse events, and radiation toxicity. Results: The median follow-up time was 28 months (range, 7-44 months). There were 3 cases of mild pneumothorax but no cases of hemothorax, dyspnea, or pyothorax after the procedure. Grade 3 or 4 acute hematologic toxicity was observed in 5 patients. During follow-up, mild fibrosis around the puncture point was observed on the CT scans of 2 patients, but both patients were asymptomatic. The overall response rates (complete and partial) for the primary mass and positive lymph nodes were 100% and 92.3%, respectively. The 1-year and 2-year overall survival (OS) rates were 90.9% and 67%, respectively, with a median OS of 22.5 months. Conclusion: Our findings suggest that HDR brachytherapy is safe and feasible for peripheral locally advanced NSCLC, justifying a phase 2 clinical trial.

  10. A Study of 358 Cases of Locally Advanced Nasopharyngeal Carcinoma Receiving Intensity-Modulated Radiation Therapy: Improving the Seventh Edition of the American Joint Committee on Cancer T-Staging System

    Directory of Open Access Journals (Sweden)

    Qin Zhou

    2017-01-01

    Full Text Available To evaluate the rationality and limitations of the seventh edition of the American Joint Committee on Cancer (the 7th AJCC edition T-staging system for locally advanced nasopharyngeal carcinoma (NPC. The prognosis of 358 patients with stage T3/T4 NPC treated with intensity-modulated radiotherapy (IMRT was analyzed with the Kaplan–Meier method or the log-rank test. The 7th AJCC staging system of NPC has some limitations in that the T category is neither the significant factor in OS/LRFS nor the independent prognostic factor in OS/LRFS/DMFS/DFS (P>0.05. After adjustment by anatomic structures, univariate analysis has shown that the adjusted-T category has statistical significance between T3 and T4 for OS (86.4% and 71.3%, P=0.002, LRFS (97% and 90.9%, P=0.048, DMFS (90.9% and 77.2%, P=0.001, and DFS (86.2% and 67.5%, P=0.000, and multivariate analysis has shown that the adjusted-T category is an independent prognostic factor for OS/DMFS/DFS (with the exception of LRFS. Then, GTV-P was taken into consideration. Multivariate analysis showed that these nT categories serve as suitable independent prognostic factors for OS/DMFS/DFS (P<0.001 and LRFS (HR = 3.131; 95% CI, 1.090–8.990; P=0.043. The 7th AJCC staging system has limitations and should be improved by including the modifications suggested, such as anatomic structures and tumor volume adjustment.

  11. Predictors of High-grade Esophagitis After Definitive Three-dimensional Conformal Therapy, Intensity-modulated Radiation Therapy, or Proton Beam Therapy for Non-small cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Daniel R., E-mail: dgomez@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Tucker, Susan L. [Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Martel, Mary K.; Mohan, Radhe; Balter, Peter A. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Lopez Guerra, Jose Luis [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Radiation Oncology, Hospitales Universitarios Virgen del Rocio, Seville (Spain); Liu Hongmei; Komaki, Ritsuko; Cox, James D.; Liao Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2012-11-15

    Introduction: We analyzed the ability of various patient- and treatment-related factors to predict radiation-induced esophagitis (RE) in patients with non-small cell lung cancer (NSCLC) treated with three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), or proton beam therapy (PBT). Methods and Materials: Patients were treated for NSCLC with 3D-CRT, IMRT, or PBT at MD Anderson from 2000 to 2008 and had full dose-volume histogram (DVH) data available. The endpoint was severe (grade {>=}3) RE. The Lyman-Kutcher-Burman (LKB) model was used to analyze RE as a function of the fractional esophageal DVH, with clinical variables included as dose-modifying factors. Results: Overall, 652 patients were included: 405 patients were treated with 3D-CRT, 139 with IMRT, and 108 with PBT; corresponding rates of grade {>=}3 RE were 8%, 28%, and 6%, respectively, with a median time to onset of 42 days (range, 11-93 days). A fit of the fractional DVH LKB model demonstrated that the fractional effective dose was significantly different (P=.046) than 1 (fractional mean dose) indicating that high doses to small volumes are more predictive than mean esophageal dose. The model fit was better for 3D-CRT and PBT than for IMRT. Including receipt of concurrent chemotherapy as a dose-modifying factor significantly improved the LKB model (P=.005), and the model was further improved by including a variable representing treatment with >30 fractions. Examining individual types of chemotherapy agents revealed a trend toward receipt of concurrent taxanes and increased risk of RE (P=.105). Conclusions: Fractional dose (dose rate) and number of fractions (total dose) distinctly affect the risk of severe RE, estimated using the LKB model, and concurrent chemotherapy improves the model fit. This risk of severe RE is underestimated by this model in patients receiving IMRT.

  12. The recovery of the salivary function in the course of time among patients damaged by a cancer of the O.R.L. sphere treated by conformal irradiation with intensity modulation; La recuperation de la fonction salivaire au cours du temps chez les patients atteints de cancer de la sphere ORL traite par irradiation conformationnelle avec modulation d'intensite

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, M.; Valinta, D.; Banal, P.; Roch, P.; Bensaoula, O.; Labib, A. [Centre Rene-Huguenin, 92 - Saint-Cloud (France); Halimi, P.; Hans, S. [Hopital Europeen Georges-Pompidou, 75 - Paris (France)

    2006-11-15

    The conformal radiotherapy with intensity modulation (R.C.M.I.) has allowed for 8 patients a partial preservation of the salivary production. The salivary production was insufficient to allow a correct quality of life for patients because the decrease of salivary production had a limited clinical translation. (N.C.)

  13. 食管癌放疗后复发再程调强放疗的临床观察%Clinical efficacy of intensity modulated radiation therapy for loco-regionally recurrent e-sophageal cancer after initial radiotherapy

    Institute of Scientific and Technical Information of China (English)

    彭雷; 卢鑫; 朱兆峰

    2014-01-01

    目的:探讨调强放疗(intensity modulater radiation therapy,IMRT)在食管癌首程放疗后局部复发患者中的应用及临床观察。方法:37例首程放疗后局部复发的食管鳞癌患者,采用调强放疗技术进行二程放疗,处方剂量为(50-60)Gy/[2Gy·(25-30)f]。结果:37例患者中完全缓解(complete response,CR)7例,部分缓解(partial response,PR)20例,有效率(response rate,RR)为73.0%(27/37)。本组患者1、2、3年生存率分别为59.5%、32.4%、21.1%。放射性食管炎、骨髓抑制、胃肠道反应的发生率较高。全部病例随访资料完整。截止2012年12月,25例患者已经死亡,其中死于局部复发11例、远处转移8例、食管气管瘘2例、大出血2例、其他疾病1例、自杀1例。结论:调强放疗对于食管癌首程放疗后局部复发患者是一种较好的有效的治疗方法,能取得较好的局部控制率。%Objective:To evaluate the applications and clinical effect of intensity modulated radiation therapy (IMRT)for loco-regionally recurrent esophageal cancer after initial radiotherapy.Methods:All 37 patients with loco-regionally recurrent esophageal cancer after initial radiotherapy were treated with IMRT,with a total dose of (50-60)Gy/[2Gy·(25 -30)f].Results:Of 37 patients,7 patients achieved completed remission,20 patients achieved partial remission,the effective rate was 73.0%(27/37).The overall 1 -,2 -,3 -year survival rates were 59.5%, 32.4%,21.1%.In the radiation therapy,the incidence rates of radiation esophagitis and arrest of bone marrow were high.In followed up,until December 2012,25 patients died,1 1 from local recurrence,8 from distant metastases,2 from esophageal leak,2 from haemorrhage,1 from other disease,1 from suicide.Conclusion:To patients with loco-regionally recurrent esophageal cancer after initial radiotherapy,IMRT is an alternative effective method,can improve the local

  14. Intensity modulation with electrons: calculations, measurements and clinical applications.

    Science.gov (United States)

    Karlsson, M G; Karlsson, M; Zackrisson, B

    1998-05-01

    Intensity modulation of electron beams is one step towards truly conformal therapy. This can be realized with the MM50 racetrack microtron that utilizes a scanning beam technique. By adjusting the scan pattern it is possible to obtain arbitrary fluence distributions. Since the monitor chambers in the treatment head are segmented in both x- and y-directions it is possible to verify the fluence distribution to the patient at any time during the treatment. Intensity modulated electron beams have been measured with film and a plane parallel chamber and compared with calculations. The calculations were based on a pencil beam method. An intensity distribution at the multileaf collimator (MLC) level was calculated by superposition of measured pencil beams over scan patterns. By convolving this distribution with a Gaussian pencil beam, which has propagated from the MLC to the isocentre, a fluence distribution at isocentre level was obtained. The agreement between calculations and measurements was within 2% in dose or 1 mm in distance in the penumbra zones. A standard set of intensity modulated electron beams has been developed. These beams have been implemented in a treatment planning system and are used for manual optimization. A clinical example (prostate) of such an application is presented and compared with a standard irradiation technique.

  15. Intensity modulation with electrons: calculations, measurements and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Magnus G.; Karlsson, Mikael [Department of Radiation Physics, Umeaa University, S-901 85 Umeaa (Sweden); Zackrisson, Bjoern [Department of Oncology, Umeaa University, S-901 85 Umeaa (Sweden)

    1998-05-01

    Intensity modulation of electron beams is one step towards truly conformal therapy. This can be realized with the MM50 racetrack microtron that utilizes a scanning beam technique. By adjusting the scan pattern it is possible to obtain arbitrary fluence distributions. Since the monitor chambers in the treatment head are segmented in both x- and y-directions it is possible to verify the fluence distribution to the patient at any time during the treatment. Intensity modulated electron beams have been measured with film and a plane parallel chamber and compared with calculations. The calculations were based on a pencil beam method. An intensity distribution at the multileaf collimator (MLC) level was calculated by superposition of measured pencil beams over scan patterns. By convolving this distribution with a Gaussian pencil beam, which has propagated from the MLC to the isocentre, a fluence distribution at isocentre level was obtained. The agreement between calculations and measurements was within 2% in dose or 1 mm in distance in the penumbra zones. A standard set of intensity modulated electron beams has been developed. These beams have been implemented in a treatment planning system and are used for manual optimization. A clinical example (prostate) of such an application is presented and compared with a standard irradiation technique. (author)

  16. Metadevice for intensity modulation with sub-wavelength spatial resolution

    CERN Document Server

    Cencillo-Abad, Pablo; Plum, Eric

    2016-01-01

    Effectively continuous control over propagation of a beam of light requires light modulation with pixelation that is smaller than the optical wavelength. Here we propose a spatial intensity modulator with sub-wavelength resolution in one dimension. The metadevice combines recent advances in reconfigurable nanomembrane metamaterials and coherent all-optical control of metasurfaces. It uses nanomechanical actuation of metasurface absorber strips placed near a mirror in order to control their interaction with light from perfect absorption to negligible loss, promising a path towards dynamic beam diffraction, light focusing and holography without unwanted diffraction artefacts.

  17. Errors analysis of prone position in intensity modulated radiation therapy of cervical cancer%子宫颈癌俯卧位调强放射治疗摆位误差分析

    Institute of Scientific and Technical Information of China (English)

    邢晓汾; 郭瑞嵩; 臧志芳; 王鹤皋; 靳宏星

    2011-01-01

    Objective To study the spatial distribution of set-up errors for cervical cancer with intensity modulated radiation therapy (IMRT) and to provide referential safety margin out of clinical tumor volume (CTV) during treatment plan design. Methods Six patients with cervical cancer were treated with IMRT in prone position, belly board and thermoplastic cast was used for immobilization. Measurement were made on a daily basis setup under five consecutive treatments with electron portal images device (EPID).Portal films from two projection (one anter-posterior and one opposite lateral)were taken. Sixty portal films were analyzed. The translational and rotational deviations were analyzed by registering and comparing the bony structures of EPID and digitally reconstructed radiographs (DRR). Results The translational deviations were (3.1 ±1.8) mm, (3.9 ±3.3) mm, (4.2 ±2.6) mm in medi-lateral, cranio-caudal and anterior-posterior directions, the rotational deviations were in coronal plane (0.8±0.9)° and sagittal plane (1.2±1)°. Conclusion For the patients with cervical cancer undergoing IMRT, the margins between the CTV and PTV should be 7.1 mm in lateral direction, 10.4 mm in cranio-caudal and 10.8 mm in anterior-posterior directions. The sign on patients body can help to reduce the setup errors.%目的 研究子宫颈癌俯卧位调强放射治疗的摆位误差大小,为子宫颈癌调强放疗计划设计临床靶区体积(CTV)外放计划靶区体积(PTV)时提供参考数据.方法 选取行俯卧位调强放射治疗的子宫颈癌患者6例,所有病例治疗时身下垫有孔泡沫板,热塑成形固定膜固定.连续5 d治疗时用电子射野影像装置(EPID)拍射正侧位验证片各1张,共60张验证片,通过配准数字化重建图像(DRR)和EPID拍摄的验证片的骨性解剖结构,计算平移和旋转误差.结果 平移误差:左右方向为(3.1±1.8)mm、头脚方向为(3.9±3.3)mm、腹背方向为(4.2±2.6)mm;旋转误差冠状面为(0.8±0

  18. Pleural Intensity-Modulated Radiotherapy for Malignant Pleural Mesothelioma

    Energy Technology Data Exchange (ETDEWEB)

    Rosenzweig, Kenneth E., E-mail: ken.rosenzweig@mountsinai.org [Department of Radiation Oncology, Mount Sinai Medical Center, New York, NY (United States); Zauderer, Marjorie G. [Department of Medicine, Thoracic Oncology Service, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Laser, Benjamin [Department of Radiation Oncology, Henry Ford Hospital, Detroit, MI (United States); Krug, Lee M. [Department of Medicine, Thoracic Oncology Service, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Yorke, Ellen [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Sima, Camelia S. [Department of Epidemiology/Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Rimner, Andreas [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Flores, Raja [Department of Surgery, Mount Sinai Medical Center, New York, NY (United States); Rusch, Valerie [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    2012-07-15

    Purpose: In patients with malignant pleural mesothelioma who are unable to undergo pneumonectomy, it is difficult to deliver tumoricidal radiation doses to the pleura without significant toxicity. We have implemented a technique of using intensity-modulated radiotherapy (IMRT) to treat these patients, and we report the feasibility and toxicity of this approach. Methods and Materials: Between 2005 and 2010, 36 patients with malignant pleural mesothelioma and two intact lungs (i.e., no previous pneumonectomy) were treated with pleural IMRT to the hemithorax (median dose, 46.8 Gy; range, 41.4-50.4) at Memorial Sloan-Kettering Cancer Center. Results: Of the 36 patients, 56% had right-sided tumors. The histologic type was epithelial in 78%, sarcomatoid in 6%, and mixed in 17%, and 6% had Stage I, 28% had Stage II, 33% had Stage III, and 33% had Stage IV. Thirty-two patients (89%) received induction chemotherapy (mostly cisplatin and pemetrexed); 56% underwent pleurectomy/decortication before IMRT and 44% did not undergo resection. Of the 36 patients evaluable for acute toxicity, 7 (20%) had Grade 3 or worse pneumonitis (including 1 death) and 2 had Grade 3 fatigue. In 30 patients assessable for late toxicity, 5 had continuing Grade 3 pneumonitis. For patients treated with surgery, the 1- and 2-year survival rate was 75% and 53%, and the median survival was 26 months. For patients who did not undergo surgical resection, the 1- and 2-year survival rate was 69% and 28%, and the median survival was 17 months. Conclusions: Treating the intact lung with pleural IMRT in patients with malignant pleural mesothelioma is a safe and feasible treatment option with an acceptable rate of pneumonitis. Additionally, the survival rates were encouraging in our retrospective series, particularly for the patients who underwent pleurectomy/decortication. We have initiated a Phase II trial of induction chemotherapy with pemetrexed and cisplatin with or without pleurectomy

  19. The Effect of Flattening Filter Free on Three-dimensional Conformal Radiation Therapy (3D-CRT), Intensity-Modulated Radiation Therapy (IMRT), and Volumetric Modulated Arc Therapy (VMAT) Plans for Metastatic Brain Tumors from Non-small Cell Lung Cancer.

    Science.gov (United States)

    Shi, Li-Wan; Lai, You-Qun; Lin, Qin; Ha, Hui-Ming; Fu, Li-Rong

    2015-07-01

    Flattening filter free (FFF) may affect outcome measures of radiotherapy. The objective of this study is to compare the dosimetric parameters in three types of radiotherapy plans, three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT), with or without the flattening filter (FF), developed for the treatment of metastatic brain tumors from non-small cell lung cancer (NSCLC). From July 2013 to October 2013, 3D-CRT, IMRT, and VMAT treatment plans were designed using 6 MV and 10 MV, with and without FF, for 10 patients with brain metastasis from NSCLC. The evaluation of the treatment plans included homogeneity index (HI), conformity index (CI), monitor units (MU), mean dose (Dmean), treatment time, and the influence of FFF on volumes. There was no difference in CI or HI between FFF and FF models with 3D-CRT, IMRT, and VMAT plans. At 6 MV, a lower Dmean was seen in the FFF model of 3D-CRT and in the VMAT plan at 10 MV. In the IMRT 6 MV, IMRT 10 MV, and VMAT 10 MV plans, higher MUs were seen in the FFF models. FFF treatments are similar in quality to FF plans, generally lead to more monitor units, and are associated with shorter treatment times. FFF plans ranked by the order of superiority in terms of a time advantage are VMAT, 3D-CRT, and IMRT.

  20. Prognostic Significance of Carbohydrate Antigen 19-9 in Unresectable Locally Advanced Pancreatic Cancer Treated With Dose-Escalated Intensity Modulated Radiation Therapy and Concurrent Full-Dose Gemcitabine: Analysis of a Prospective Phase 1/2 Dose Escalation Study

    Energy Technology Data Exchange (ETDEWEB)

    Vainshtein, Jeffrey M., E-mail: jvainsh@med.umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Schipper, Matthew [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Zalupski, Mark M. [Division of Hematology Oncology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan (United States); Lawrence, Theodore S. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Abrams, Ross [Department of Radiation Oncology, Rush Medical Center, Chicago, Illinois (United States); Francis, Isaac R. [Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Khan, Gazala [Division of Hematology Oncology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan (United States); Leslie, William [Division of Hematology Oncology, Department of Internal Medicine, Rush Medical Center, Chicago, Illinois (United States); Ben-Josef, Edgar [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania (United States)

    2013-05-01

    Purpose: Although established in the postresection setting, the prognostic value of carbohydrate antigen 19-9 (CA19-9) in unresectable locally advanced pancreatic cancer (LAPC) is less clear. We examined the prognostic utility of CA19-9 in patients with unresectable LAPC treated on a prospective trial of intensity modulated radiation therapy (IMRT) dose escalation with concurrent gemcitabine. Methods and Materials: Forty-six patients with unresectable LAPC were treated at the University of Michigan on a phase 1/2 trial of IMRT dose escalation with concurrent gemcitabine. CA19-9 was obtained at baseline and during routine follow-up. Cox models were used to assess the effect of baseline factors on freedom from local progression (FFLP), distant progression (FFDP), progression-free survival (PFS), and overall survival (OS). Stepwise forward regression was used to build multivariate predictive models for each endpoint. Results: Thirty-eight patients were eligible for the present analysis. On univariate analysis, baseline CA19-9 and age predicted OS, CA19-9 at baseline and 3 months predicted PFS, gross tumor volume (GTV) and black race predicted FFLP, and CA19-9 at 3 months predicted FFDP. On stepwise multivariate regression modeling, baseline CA19-9, age, and female sex predicted OS; baseline CA19-9 and female sex predicted both PFS and FFDP; and GTV predicted FFLP. Patients with baseline CA19-9 ≤90 U/mL had improved OS (median 23.0 vs 11.1 months, HR 2.88, P<.01) and PFS (14.4 vs 7.0 months, HR 3.61, P=.001). CA19-9 progression over 90 U/mL was prognostic for both OS (HR 3.65, P=.001) and PFS (HR 3.04, P=.001), and it was a stronger predictor of death than either local progression (HR 1.46, P=.42) or distant progression (HR 3.31, P=.004). Conclusions: In patients with unresectable LAPC undergoing definitive chemoradiation therapy, baseline CA19-9 was independently prognostic even after established prognostic factors were controlled for, whereas CA19-9 progression

  1. Impact of Intensity-Modulated Radiation Therapy Technique for Locally Advanced Non-Small-Cell Lung Cancer: A Secondary Analysis of the NRG Oncology RTOG 0617 Randomized Clinical Trial.

    Science.gov (United States)

    Chun, Stephen G; Hu, Chen; Choy, Hak; Komaki, Ritsuko U; Timmerman, Robert D; Schild, Steven E; Bogart, Jeffrey A; Dobelbower, Michael C; Bosch, Walter; Galvin, James M; Kavadi, Vivek S; Narayan, Samir; Iyengar, Puneeth; Robinson, Clifford G; Wynn, Raymond B; Raben, Adam; Augspurger, Mark E; MacRae, Robert M; Paulus, Rebecca; Bradley, Jeffrey D

    2017-01-01

    Purpose Although intensity-modulated radiation therapy (IMRT) is increasingly used to treat locally advanced non-small-cell lung cancer (NSCLC), IMRT and three-dimensional conformal external beam radiation therapy (3D-CRT) have not been compared prospectively. This study compares 3D-CRT and IMRT outcomes for locally advanced NSCLC in a large prospective clinical trial. Patients and Methods A secondary analysis was performed to compare IMRT with 3D-CRT in NRG Oncology clinical trial RTOG 0617, in which patients received concurrent chemotherapy of carboplatin and paclitaxel with or without cetuximab, and 60- versus 74-Gy radiation doses. Comparisons included 2-year overall survival (OS), progression-free survival, local failure, distant metastasis, and selected Common Terminology Criteria for Adverse Events (version 3) ≥ grade 3 toxicities. Results The median follow-up was 21.3 months. Of 482 patients, 53% were treated with 3D-CRT and 47% with IMRT. The IMRT group had larger planning treatment volumes (median, 427 v 486 mL; P = .005); a larger planning treatment volume/volume of lung ratio (median, 0.13 v 0.15; P = .013); and more stage IIIB disease (30.3% v 38.6%, P = .056). Two-year OS, progression-free survival, local failure, and distant metastasis-free survival were not different between IMRT and 3D-CRT. IMRT was associated with less ≥ grade 3 pneumonitis (7.9% v 3.5%, P = .039) and a reduced risk in adjusted analyses (odds ratio, 0.41; 95% CI, 0.171 to 0.986; P = .046). IMRT also produced lower heart doses ( P < .05), and the volume of heart receiving 40 Gy (V40) was significantly associated with OS on adjusted analysis ( P < .05). The lung V5 was not associated with any ≥ grade 3 toxicity, whereas the lung V20 was associated with increased ≥ grade 3 pneumonitis risk on multivariable analysis ( P = .026). Conclusion IMRT was associated with lower rates of severe pneumonitis and cardiac doses in NRG Oncology clinical trial RTOG 0617, which supports

  2. 保乳术后全乳照射 VMAT 与 IMRT 的计量学比较%Dosimetric comparison of volumetric -modulated arc therapy and intensity -modulated radiation therapy for breast cancer

    Institute of Scientific and Technical Information of China (English)

    赵金; 吴文安; 廖娟; 雎岩; 梁静; 宋丽萍

    2016-01-01

    目的:比较保乳术后全乳照射 VMAT 与静态 IMRT 的剂量学差异,探索 VMAT 的可行性。方法:2014年-2015年入组乳腺癌患者10例,左侧、右侧乳腺癌各5例。用 Varian Eclipse 计划系统分别设计双弧VMAT 和5野 IMRT 计划,PTV 处方剂量50Gy 分25次,用 Delta 4进行剂量验证。配对 t 检验比较两组计划PTV、OAR 受量、机器跳数及有效治疗时间。结果:两组计划均能满足临床剂量学要求。 VMAT 与 IMRT相比CI 值分别为(1.01±0.1)和(1.36±0.2)(P <0.05);HI 值分别为(0.124±0.01)和(0.173±0.02)(P <0.05);心脏 V20、V30、Dmean增高(P =0.041、0.012、0.002);肺 V20-V30无明显统计学差异,但是增加了患侧肺的 V5(58.2±3.5)% vs (51.4±4.2)%(P <0.05);机器跳数分别为(452±98)和(786±32)(P <0.05);有效治疗时间(2.5±0.89)min 和(15±1.78)min(P <0.05)。结论:在靶区覆盖率相似前提下,VMAT 可降低部分 OAR 受量,并能改善 CI 值、减少机器跳数、缩短有效治疗时间。Synergy 平台上的 VMAT 计划剂量稳定可靠。%Objective:To compare the dosimetric difference in VMAT and IMRT planning for breast cancer.Methods:Varian Eclipse,ten patients received radiotherapy alone after breast-conserving surgery were randomly selected.For each patient,two plans(VMAT and IMRT)were designed.In each plan,the volume of planning target volume (PTV)received prescription dose was not less than 95%.The dosimetric parameters were assessed with dosevolume histogram (DVH)and mean dose in PTV and organ at risk(OAR).Results:The irradition volume and meandose of heart and V5 of the lung can be increased by VMAT.Better conformal index(CI)and homogeneity index (HI)of PTV can be achieved.The MU and the therapy time can be reduced by the VMAT.Conclusion:The design ofVMAT plan for breast cancer should

  3. Pump-to-Signal Intensity Modulation Transfer in Saturated- Gain Fiber Optical Parametric Amplifiers

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Lund-Hansen, Toke; Rottwitt, Karsten

    2011-01-01

    The pump-to-signal intensity modulation transfer in saturated degenerate FOPAs is numerically investigated over the whole gain bandwidth. The intensity modulation transfer decreases and the OSNR improves when the amplifier operates in the saturation regime....

  4. Similarities between static and rotational intensity-modulated plans

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Q Jackie; Yin Fangfang; McMahon, Ryan; Zhu Xiaofeng; Das, Shiva K [Department of Radiation Oncology, Duke University School of Medicine, Durham, NC 27710 (United States)], E-mail: jackie.wu@duke.edu

    2010-01-07

    The aim of this study was to explore similarities between intensity-modulated radiotherapy (IMRT) and intensity-modulated arc therapy (IMAT) techniques in the context of the number of multi-leaf collimator (MLC) segments required to achieve plan objectives, the major factor influencing plan quality. Three clinical cases with increasing complexity were studied: (a) prostate only, (b) prostate and seminal vesicles and (c) prostate and pelvic lymph nodes. Initial 'gold-standard' plans with the maximum possible organ-at-risk sparing were generated for all three cases. For each case, multiple IMRT and IMAT plans were generated with varying intensity levels (IMRT) and arc control points (IMAT), which translate into varying MLC segments in both modalities. The IMAT/IMRT plans were forced to mimic the organ-at-risk sparing and target coverage in the gold-standard plans, thereby only allowing the target dose inhomogeneity to be variable. A higher target dose inhomogeneity (quantified as D5-dose to the highest 5% of target volume) implies that the plan is less capable of modulation. For each case, given a similar number of MLC segments, both IMRT and IMAT plans exhibit similar target dose inhomogeneity, indicating that there is no difference in their ability to provide dose painting. Target dose inhomogeneity remained approximately constant with decreasing segments, but sharply increased below a specific critical number of segments (70, 100, 110 for cases a, b, c, respectively). For the cases studied, IMAT and IMRT plans are similar in their dependence on the number of MLC segments. A minimum critical number of segments are required to ensure adequate plan quality. Future studies are needed to establish the range of minimum critical number of segments for different treatment sites and target-organ geometries.

  5. Similarities between static and rotational intensity-modulated plans

    Science.gov (United States)

    Wu, Q. Jackie; Yin, Fang-Fang; McMahon, Ryan; Zhu, Xiaofeng; Das, Shiva K.

    2010-01-01

    The aim of this study was to explore similarities between intensity-modulated radiotherapy (IMRT) and intensity-modulated arc therapy (IMAT) techniques in the context of the number of multi-leaf collimator (MLC) segments required to achieve plan objectives, the major factor influencing plan quality. Three clinical cases with increasing complexity were studied: (a) prostate only, (b) prostate and seminal vesicles and (c) prostate and pelvic lymph nodes. Initial 'gold-standard' plans with the maximum possible organ-at-risk sparing were generated for all three cases. For each case, multiple IMRT and IMAT plans were generated with varying intensity levels (IMRT) and arc control points (IMAT), which translate into varying MLC segments in both modalities. The IMAT/IMRT plans were forced to mimic the organ-at-risk sparing and target coverage in the gold-standard plans, thereby only allowing the target dose inhomogeneity to be variable. A higher target dose inhomogeneity (quantified as D5—dose to the highest 5% of target volume) implies that the plan is less capable of modulation. For each case, given a similar number of MLC segments, both IMRT and IMAT plans exhibit similar target dose inhomogeneity, indicating that there is no difference in their ability to provide dose painting. Target dose inhomogeneity remained approximately constant with decreasing segments, but sharply increased below a specific critical number of segments (70, 100, 110 for cases a, b, c, respectively). For the cases studied, IMAT and IMRT plans are similar in their dependence on the number of MLC segments. A minimum critical number of segments are required to ensure adequate plan quality. Future studies are needed to establish the range of minimum critical number of segments for different treatment sites and target-organ geometries.

  6. Dose profile analysis of small fields in intensity modulated radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Medel B, E. [IMSS, Centro Medico Nacional Manuel Avila Camacho, Calle 2 Nte. 2004, Barrio de San Francisco, 72090 Puebla, Pue. (Mexico); Tejeda M, G.; Romero S, K., E-mail: romsakaren@gmail.com [Benemerita Universidad Autonoma de Puebla, Facultad de Ciencias Fisico Matematicas, Av. San Claudio y 18 Sur, Ciudad Universitaria, 72570 Puebla, Pue.(Mexico)

    2015-10-15

    Full text: Small field dosimetry is getting a very important worldwide task nowadays. The use of fields of few centimeters is more common with the introduction of sophisticated techniques of radiation therapy, as Intensity Modulated Radiotherapy (IMRT). In our country the implementation of such techniques is just getting started and whit it the need of baseline data acquisition. The dosimetry under small field conditions represents a challenge for the physicists community. In this work, a dose profile analysis was done, using various types of dosimeters for further comparisons. This analysis includes the study of quality parameters as flatness, symmetry, penumbra, and other in-axis measurements. (Author)

  7. The potential benefit of swallowing sparing intensity modulated radiotherapy to reduce swallowing dysfunction : An in silico planning comparative study

    NARCIS (Netherlands)

    van der Laan, Hans Paul; Christianen, Miranda E M C; Bijl, Hendrik P; Schilstra, C; Langendijk, Johannes A

    2012-01-01

    PURPOSE: To apply recently developed predictive models for swallowing dysfunction to compare the predicted probabilities of swallowing dysfunction for standard intensity modulated radiotherapy (ST-IMRT) and swallowing sparing IMRT (SW-IMRT). MATERIALS AND METHODS: Thirty head and neck cancer patient

  8. 食管癌两种旋转调强放疗技术剂量学对比研究%Dosimetric study of two intensity-modulated arc radiotherapy in esophageal cancer

    Institute of Scientific and Technical Information of China (English)

    张若辉; 樊晓妹; 白文文; 李润霄; 曹彦坤; 韩春; 迟子锋

    2014-01-01

    Objective Comparing the dosimetric characteristics of volumetric modulated arc therapy (VMAT) and constant dose rate intensity modulated arc therapy (IMAT) in esophagus cancer to evaluate the performance of the two different arc therapy delivery techniques.Methods 22 cases of esophageal cancer patients were selected for the planning comparison study.All plans were done for IMAT and VMAT treatment plans on Oncentra 4.1 treatment planning system,prescription dose of 2 Gy in total 30 fractions.Planning objectives for PTV were at least 95% reached the prescription dose and V110 no more than 10%.The maximum dose of spinalcord below 45 Gy and double lung dose V20 ≤ 28%,V30 ≤ 18% were constrained.Plans were evaluated based on the ability to meet the dose volume histogram.The dose homogeneity index (HI),radiation conformity index (CI),radiation delivery time,monitor units and γ pass rate were also compared.SPSS 19.0 software paired ttest analysis was carried out on the two sets of data.Results The results showed that the IMAT plans in terms of the PTV's CI (t =3.35,P=0.003),D2(t =-2.27,P=0.034) lung's V30(t =-2.46,P=0.023) were better than that of VMAT group.But the VMAT plans spinal's V40 (t =2.37,P =0.027),lung's V5 (t =2.43,P =0.024) were superior to that of IMAT plans.There were no significant differences between IMAT and VMAT plans in the average dose of PTV,CTV,GTV,heart,spinal cord,double lung and the γpass rate.Conclusion IMAT presents a slight improvement in the OAR sparing in high dose with shorter treatment time when compared to VMAT.While in terms of delivered MU and tissue of low dose irradiated area is higher than that of in VMAT.These two treatment methods all can meet the clinical demand,which should be selected according to the actual situation of the patient.%目的 通过比较食管癌容积旋转调强放疗(VMAT)与固定剂量率旋转调强放疗(IMAT)计划,分析VMAT与IMAT在剂量学方面的特点.方法 对入组的22例

  9. Residual intensity modulation in resonator fiber optic gyros with sinusoidal wave phase modulation

    Institute of Scientific and Technical Information of China (English)

    Di-qing YING; Qiang LI; Hui-lian MA; Zhong-he JIN

    2014-01-01

    We present how residual intensity modulation (RIM) affects the performance of a resonator fiber optic gyro (R-FOG) through a sinusoidal wave phase modulation technique. The expression for the R-FOG system’s demodulation curve under RIM is obtained. Through numerical simulation with different RIM coefficients and modulation frequencies, we find that a zero deviation is induced by the RIM effect on the demodulation curve, and this zero deviation varies with the RIM coefficient and modulation frequency. The expression for the system error due to this zero deviation is derived. Simulation results show that the RIM-induced error varies with the RIM coefficient and modulation frequency. There also exists optimum values for the RIM coefficient and modulation frequency to totally eliminate the RIM-induced error, and the error increases as the RIM coefficient or modulation frequency deviates from its optimum value;however, in practical situations, these two parameters would not be exactly fixed but fluctuate from their respective optimum values, and a large system error is induced even if there exists a very small deviation of these two critical parameters from their optimum values. Simulation results indicate that the RIM-induced error should be con-sidered when designing and evaluating an R-FOG system.

  10. 宫颈癌术后常规与旋转容积调强放疗计划剂量学研究%Dosimetric study of conventional intensity-modulated radiotherapy and volumetric intensity-modulated arc radiotherapy for postoperation of cervix cancer

    Institute of Scientific and Technical Information of China (English)

    李军; 陈雪梅; 张西志; 张先稳; 花威; 汤晓斌; 柴磊; 陈达

    2014-01-01

    目的:比较研究宫颈癌常规调强放疗(conventional intensity-modulated radiotherapy,C-IMRT)与旋转容积调强放疗(volumetric intensity-modulated arc therapy,VMAT)计划对靶区及其周围危及器官受照剂量的差异.方法:随机选择2012-08-01-2013-05-31苏北人民医院收治的12例宫颈癌术后患者,进行CT模拟定位、靶区和危及器官的勾画,在同一CT图像上用治疗计划系统进行C-IMRT和VMAT计划设计,处方剂量均为CTV 50 Gy,分25次,危及器官限量参考临床要求.在95%体积的PTV达到处方剂量的条件下,比较2种计划的剂量体积直方图,靶区、危及器官、靶区剂量适形度、剂量分布均匀性、机器跳数(monitor unit,MU)和治疗时间.对治疗计划结果采用配对t检验分析方法评价各指标的差异性.结果:VMAT计划与C-IMRT计划相比,膀胱的Dmean和V20两者差异无统计学意义,P>0.05;D50、V30和V40均明显降低(P<0.05),且直肠的D5和小肠的D1也明显降低(P<0.05),其他的危及器官的剂量学参数均没有明显降低.正常组织V10 VMAT计划明显高于C-IMRT计划(P<0.05),而V30VMAT计划明显低于C-IMRT计划,P<0.05.VMAT计划相比于C-IMRT计划MU平均减少了50.7%;出束时间T减少了47.2%.结论:在宫颈癌术后放疗中,VMAT技术较C-IMRT技术有剂量学方面的优势,患者的治疗时间和机器跳数MU显著降低,在综合条件允许的情况下可推荐使用VMAT技术.

  11. A computational implementation and comparison of several intensity modulated proton therapy treatment planning algorithms.

    Science.gov (United States)

    Li, Haisen S; Romeijn, H Edwin; Fox, Christopher; Palta, Jatinder R; Dempsey, James F

    2008-03-01

    The authors present a comparative study of intensity modulated proton therapy (IMPT) treatment planning employing algorithms of three-dimensional (3D) modulation, and 2.5-dimensional (2.5D) modulation, and intensity modulated distal edge tracking (DET) [A. Lomax, Phys. Med. Biol. 44, 185-205 (1999)] applied to the treatment of head-and-neck cancer radiotherapy. These three approaches were also compared with 6 MV photon intensity modulated radiation therapy (IMRT). All algorithms were implemented in the University of Florida Optimized Radiation Therapy system using a finite sized pencil beam dose model and a convex fluence map optimization model. The 3D IMPT and the DET algorithms showed considerable advantages over the photon IMRT in terms of dose conformity and sparing of organs at risk when the beam number was not constrained. The 2.5D algorithm did not show an advantage over the photon IMRT except in the dose reduction to the distant healthy tissues, which is inherent in proton beam delivery. The influences of proton beam number and pencil beam size on the IMPT plan quality were also studied. Out of 24 cases studied, three cases could be adequately planned with one beam and 12 cases could be adequately planned with two beams, but the dose uniformity was often marginally acceptable. Adding one or two more beams in each case dramatically improved the dose uniformity. The finite pencil beam size had more influence on the plan quality of the 2.5D and DET algorithms than that of the 3D IMPT. To obtain a satisfactory plan quality, a 0.5 cm pencil beam size was required for the 3D IMPT and a 0.3 cm size was required for the 2.5D and the DET algorithms. Delivery of the IMPT plans produced in this study would require a proton beam spot scanning technique that has yet to be developed clinically.

  12. Quantitative shadowgraphy and proton radiography for large intensity modulations

    CERN Document Server

    Kasim, Muhammad Firmansyah; Ratan, Naren; Sadler, James; Chen, Nicholas; Savert, Alexander; Trines, Raoul; Bingham, Robert; Burrows, Philip N; Kaluza, Malte C; Norreys, Peter

    2016-01-01

    Shadowgraphy is a technique widely used to diagnose objects or systems in various fields in physics and engineering. In shadowgraphy, an optical beam is deflected by the object and then the intensity modulation is captured on a screen placed some distance away. However, retrieving quantitative information from the shadowgrams themselves is a challenging task because of the non-linear nature of the process. Here, a novel method to retrieve quantitative information from shadowgrams, based on computational geometry, is presented for the first time. This process can be applied to proton radiography for electric and magnetic field diagnosis in high-energy-density plasmas and has been benchmarked using a toroidal magnetic field as the object, among others. It is shown that the method can accurately retrieve quantitative parameters with error bars less than 10%, even when caustics are present. The method is also shown to be robust enough to process real experimental results with simple pre- and post-processing techn...

  13. Intensity-Modulated Radiation Therapy for Primary Brain Tumors

    Institute of Scientific and Technical Information of China (English)

    Zhong-min Wang

    2004-01-01

    Radiation therapy has been used to treat primary brain tumors as standard primary and/or adjunctive therapies for decades. It is difficult for conventional radiotherapy to deliver a lethal dose of radiation to the tumors while sparing surrounding normal brain due to complicated structures and multifunction in human brain. With the understanding of radiation physics and computer technology, a number of novel and more precise radiotherapies have been developed in recent years. Intensity modulated radiotherapy (IMRT) is one of these strategies. The use of IMRT in the treatment of primary brain tumors is being increasing nowadays. It shows great promise for some of primary brain tumors and also presents some problems, This review highlights current IMRT in the treatment of mainly primary brain tumors.

  14. Subcarrier Intensity Modulated Optical Wireless Communications:A Survey from Communication Theory Perspective

    Institute of Scientific and Technical Information of China (English)

    Md Zoheb Hassan; Md Jahangir Hossain; Julian Cheng; Victor C M Leung

    2016-01-01

    Subcarrier intensity modulation with direct detection is a modulation/detection technique for optical wireless communication sys⁃tems, where a pre⁃modulated and properly biased radio frequency signal is modulated on the intensity of the optical carrier. The most important benefits of subcarrier intensity modulation are as follows: 1) it does not provide irreducible error floor like the con⁃ventional on⁃off keying intensity modulation with a fixed detection threshold; 2) it provides improved spectral efficiency and sup⁃ports higher order modulation schemes; and 3) it has much less implementation complexity compared to coherent optical wireless communications with heterodyne or homodyne detection. In this paper, we present an up⁃to⁃date review of subcarrier intensity modulated optical wireless communication systems. We survey the error rate and outage performance of subcarrier intensity modu⁃lations in the atmospheric turbulence channels considering different modulation and coding schemes. We also explore different contemporary atmospheric turbulence fading mitigation solutions that can be employed for subcarrier intensity modulation. These solutions include diversity combining, adaptive transmission, relay assisted transmission, multiple⁃subcarrier intensity modulations, and optical orthogonal frequency division multiplexing. Moreover, we review the performance of subcarrier intensity modulations due to the pointing error and synchronization error.

  15. Estimating the costs of intensity-modulated and 3-dimensional conformal radiotherapy in Ontario

    Science.gov (United States)

    Yong, J.H.E.; McGowan, T.; Redmond-Misner, R.; Beca, J.; Warde, P.; Gutierrez, E.; Hoch, J.S.

    2016-01-01

    Background Radiotherapy is a common treatment for many cancers, but up-to-date estimates of the costs of radiotherapy are lacking. In the present study, we estimated the unit costs of intensity-modulated radiotherapy (imrt) and 3-dimensional conformal radiotherapy (3D-crt) in Ontario. Methods An activity-based costing model was developed to estimate the costs of imrt and 3D-crt in prostate cancer. It included the costs of equipment, staff, and supporting infrastructure. The framework was subsequently adapted to estimate the costs of radiotherapy in breast cancer and head-and-neck cancer. We also tested various scenarios by varying the program maturity and the use of volumetric modulated arc therapy (vmat) alongside imrt. Results From the perspective of the health care system, treating prostate cancer with imrt and 3D-crt respectively cost $12,834 and $12,453 per patient. The cost of radiotherapy ranged from $5,270 to $14,155 and was sensitive to analytic perspective, radiation technique, and disease site. Cases of head-and-neck cancer were the most costly, being driven by treatment complexity and fractions per treatment. Although imrt was more costly than 3D-crt, its cost will likely decline over time as programs mature and vmat is incorporated. Conclusions Our costing model can be modified to estimate the costs of 3D-crt and imrt for various disease sites and settings. The results demonstrate the important role of capital costs in studies of radiotherapy cost from a health system perspective, which our model can accommodate. In addition, our study established the need for future analyses of imrt cost to consider how vmat affects time consumption. PMID:27330359

  16. Mach-Zehnder Type Annealed Proton Exchange Waveguide and Coplanar Waveguide Modulation Electrode LiNbO3 Intensity Modulator

    Institute of Scientific and Technical Information of China (English)

    HE Jian; ZHU Xue-jun

    2007-01-01

    The characteristics of a conventional LiNbO3 intensity modulator made up of a Mach-Zehnder(MZ) type annealed proton exchange(APE) waveguide and coplanar waveguide(CPW) modulation electrode are presented. The APE waveguide characteristics and their relations with process parameters are analyzed. At the same time, the electrical characteristics of modulation electrode, such as modulation voltage, microwave effective index associated with modulation bandwidth, characteristics impedance, are also investigated in detail.

  17. Modulation Electric Field Intensity Sensor in a Conductive Medium

    Directory of Open Access Journals (Sweden)

    O. I. Miseyk

    2015-01-01

    Full Text Available The requirement to conduct measurements across the big water areas and in the ocean depths arises a problem of creating devices to measure an electric field, being either set on the high-speed mobile carriers, or implemented as the sounders, which investigate a vertical or horizontal structure of the electric field of ocean. Manufactured, designed, and hypothetical devices for measuring poor electric fields of the ocean were analyzed. The analysis allowed us to prove that there is a need in creation of modulation sensors (with modulation of a non-electric origin either with periodically changing capabilities of measuring bases, or with space-changing (and therefore, time-changing position of measuring base of primary converters, as the most effective in terms of allocation and measurement of the modulated signal from unmodulated noise.The paper considers the mathematical models of modulation sensors of electric field intensity in the ultralow-frequency range, which are set on the mobile carriers. It justifies a choice of two basic models of primary converters with a change of the measuring base in space, i.e. with the "changing" base and with the "rotating" base. A feature of the offered models with vertical sounding is the minimum value of noise because of rotation of measuring electrodes in a magnetic field of Earth, and hydrodynamic noise. The paper shows that noise caused by the relative movement of sensor and water completely disappears in two cases:1. for a vertical sounder in the autonomous mode or a horizontal sounder with zero buoyancy in the specified shape of water;2. in a case when the sensor has no component of measuring base in the considered area, for example, for the sensor with in-line array of electrodes located in the horizontal plane.The paper proves advantage of the model with "rotating" measuring base, which provides the maximum power transfer from the primary converter to loading for all relative positions of an external

  18. 直肠癌术前容积调强与固定野调强技术的剂量学比较%Dosimetric Comparison between Preoperative Volumetric Modulated Arc Therapy and Fixed-field Intensity-modulated Radiotherapy for Rectal Cancer

    Institute of Scientific and Technical Information of China (English)

    杨波; 庞廷田; 孙显松; 胡克; 邱杰; 张福泉

    2014-01-01

    Objective To compare the dosimetric characteristics of preoperative volumetric modulated arc therapy ( VMAT) and fixed-field intensity-modulated radiotherapy ( FF-IMRT) for rectal cancer .Methods The CT images of 15 patients with rectal cancer were transferred into Eclipse planning system .FF-IMRT and VMAT plans were optimized on an Eclipse treatment planning system using beam data generated for Varian Trilogy linear accelerator .Same institutional dose-volume constraints for rectal cancer were used in both techniques .Targets and organs at risk were evaluated .Results The target volume coverage could meet the requirement of described dosage in both VMAT plan group and FF-IMRT plan group .Compared with the FF-IMRT plan group , the plan-ning target volume ( PTV) 105% ( PTV105%) coverage, Dmean, and Dmax significantly increased in the VMAT plan group ( P=0.011, P=0.017, and P=0.006, respectively), the radiation conformity index (CI) significantly decreased ( P=0.008 ) , and the homogeneity index showed no significant difference ( P=0.193 ) . Compared with the FF-IMRT plan group , the V50 of the bladder in the VMAT plan group was increased by about 15%( P=0.009 ) , and the Dmax increased by 0.7 Gy ( P=0.003 );the V30 of the small intestine decreased by 10% (P=0.004), and the Dmax was increased by 0.9 Gy (P=0.000); the V10, V30, and V40 of the bone marrow reduced by 2%, 10%, and 10%( P=0.000 , P=0.000 , and P=0.000 ) , and the Dmean re-duced by 1.7 Gy ( P=0.000 );the D5 of the left and right femoral heads reduced by 3.2 Gy and 2.4 Gy ( P=0.000 , P=0.000 ); the V10 , V20 , V30 , and V40 of the body also significantly decreased ( P=0.003 , P=0.000 , P=0.000 , and P=0.004 ) .The VMAT group also had significantly lower number of monitor units ( MU) when compared with the FF-IMRT plan group ( P=0.000 ) .Conclusions In patients with rectal canc-er, preoperative VMAT can achieve equivalent or superior dose distribution compared with the FF -IMRT.In addi-tion, VMAT can

  19. High speed traveling wave electrooptic intensity modulator with a doped PIN semiconductor junction

    Energy Technology Data Exchange (ETDEWEB)

    Vawter, G.A.; Hietala, V.M.; Wendt, J.R.; Fuchs, B.A.; Hafich, M.; Housel, M.; Armendariz, M.; Sullivan, C.T.

    1996-02-01

    A high-electrooptic-efficiency Mach-Zehnder intensity modulator is demonstrated with a bandwidth exceeding 40 GHZ. The 1 mm-long modulator has a switching voltage comparable to undoped semiconductor designs of much greater length.

  20. Prioritized efficiency optimization for intensity modulated proton therapy

    Science.gov (United States)

    Müller, Birgit S.; Wilkens, Jan J.

    2016-12-01

    A high dosimetric quality and short treatment time are major goals in radiotherapy planning. Intensity modulated proton therapy (IMPT) plans obtain dose distributions of great conformity but often result in long delivery times which are typically not incorporated into the optimization process. We present an algorithm to optimize delivery efficiency of IMPT plans while maintaining plan quality, and study the potential trade-offs of these interdependent objectives. The algorithm is based on prioritized optimization, a stepwise approach to implemented objectives. First the quality of the plan is optimized. The second step of the prioritized efficiency optimization (PrEfOpt) routine offers four alternatives for reducing delivery time: minimization of the total spot weight sum (A), maximization of the lowest spot intensity of each energy layer (B), elimination of low-weighted spots (C) or energy layers (D). The trade-off between dosimetric quality (step I) and treatment time (step II) is controlled during the optimization by option-dependent parameters. PrEfOpt was applied to a clinical patient case, and plans for different trade-offs were calculated. Delivery times were simulated for two virtual facilities with constant and variable proton current, i.e. independent and dependent on the optimized spot weight distributions. Delivery times decreased without major degradation of plan quality; absolute time reductions varied with the applied method and facility type. Minimizing the total spot weight sum (A) reduced times by 28% for a similar plan quality at a constant current (changes of minimum dose in the target  qualities. A potential clinical application of PrEfOpt is the generation of multiple plans with different trade-offs for a multicriteria optimization setting. Then, the planner can select the preferred compromise between treatment time and quality for each individual patient.

  1. Modulating autophagy: a strategy for cancer therapy

    Institute of Scientific and Technical Information of China (English)

    Jun-Lin Li; Shao-Liang Han; Xia Fan

    2011-01-01

    Autophagy is a process in which long-lived proteins,damaged cell organelles,and other cellular particles are sequestered and degraded.This process is important for maintaining the cellular microenvironment when the cell is under stress.Many studies have shown that autophagy plays a complex role in human diseases,especially in cancer,where it is known to have paradoxical effects.Namely,autophagy provides the energy for metabolism and tumor growth and leads to cell death that promotes tumor suppression.The link between autophagy and cancer is also evident in that some of the genes that regulate carcinogenesis,oncogenes and tumor suppressor genes,participate in or impact the autophagy process.Therefore,modulating autophagy will be a valuable topic for cancer therapy.Many studies have shown that autophagy can inhibit the tumor growth when autophagy modulators are combined with radiotherapy and/or chemotherapy.These findings suggest that autophagy may be a potent target for cancer therapy.

  2. Dosiology Comparison of Static Intensity-modulate Radiotherapy and Volumetric Modulated Arc Therapy in the Esophageal Cancer%食管癌静态调强放疗与容积调强放疗计划的剂量学比较

    Institute of Scientific and Technical Information of China (English)

    荆亮; 丁继强

    2015-01-01

    Objective To study the dosiology differences of static intensity-modulate radiotherapy( sIMRT)and volumetric modulated arc therapy( VMAT)in the esophageal cancer. Methods The sIMRT and VMAT regimens were respectively designed for 65 patients with esophageal cancer,and the dosiology parameters were compared be-tween the two groups. Results Compared with the sIMRT,the D99 ,D95 ,Dmean of GTV of the VMAT were lower( P0. 05);for the organs at risk,the V20,V30,mean dose of the VMAT were lower(P0. 05). The ray number of the sIMRT and the VMAT were respec-tively 572. 33 ± 97. 9 and 754. 95 ± 177. 6,compared with the sIMRT,the VMAT was decreased by 24%( P <0. 05). Conclusion Compared with sIMRT,VMAT can improve the target area dose,decrease the radiation time, have the better effect for esophageal cancer.%目的:研究食管癌患者应用静态调强放疗( sIMRT)和容积调强弧形治疗( VMAT)的计划剂量学差异。方法65例食管癌单纯放疗患者分别设计sIMRT、VMAT 2组计划,比较2组的剂量学参数。结果与sIMRT比较,VMAT计划的GTV的D99、D95、Dmean的剂量较低( P<0.05);PTV的99%、95%的覆盖度、最大剂量较高(P<0.05);PTV的105%覆盖度较低(P<0.05);适形指数、不均匀指数相似(P>0.05)。危及器官比较中,VMAT的双肺V20、V30、平均剂量明显低于sIMRT(P<0.05)。脊髓、心脏照射量2组相似(P>0.05)。sIMRT、VMAT的射线数分别为572.33±97.9、754.95±177.6,sIMRT相比于 VMAT降低了24%(P<0.05)。结论与sIMRT相比较,VMAT可以改善靶区剂量,减少照射时间,在食管癌的治疗中可能会有较好的疗效。

  3. Quantitative shadowgraphy and proton radiography for large intensity modulations

    Science.gov (United States)

    Kasim, Muhammad Firmansyah; Ceurvorst, Luke; Ratan, Naren; Sadler, James; Chen, Nicholas; Sävert, Alexander; Trines, Raoul; Bingham, Robert; Burrows, Philip N.; Kaluza, Malte C.; Norreys, Peter

    2017-02-01

    Shadowgraphy is a technique widely used to diagnose objects or systems in various fields in physics and engineering. In shadowgraphy, an optical beam is deflected by the object and then the intensity modulation is captured on a screen placed some distance away. However, retrieving quantitative information from the shadowgrams themselves is a challenging task because of the nonlinear nature of the process. Here, we present a method to retrieve quantitative information from shadowgrams, based on computational geometry. This process can also be applied to proton radiography for electric and magnetic field diagnosis in high-energy-density plasmas and has been benchmarked using a toroidal magnetic field as the object, among others. It is shown that the method can accurately retrieve quantitative parameters with error bars less than 10%, even when caustics are present. The method is also shown to be robust enough to process real experimental results with simple pre- and postprocessing techniques. This adds a powerful tool for research in various fields in engineering and physics for both techniques.

  4. Rationale and development of image-guided intensity-modulated radiotherapy post-prostatectomy: the present standard of care?

    Directory of Open Access Journals (Sweden)

    Murray JR

    2015-11-01

    Full Text Available Julia R Murray,1,2 Helen A McNair,2 David P Dearnaley1,2 1Academic Urology Unit, Institute of Cancer Research, London, 2Department of Radiotherapy, The Royal Marsden NHS Foundation Trust, Sutton, UK Abstract: The indications for post-prostatectomy radiotherapy have evolved over the last decade, although the optimal timing, dose, and target volume remain to be well defined. The target volume is susceptible to anatomical variations with its borders interfacing with the rectum and bladder. Image-guided intensity-modulated radiotherapy has become the gold standard for radical prostate radiotherapy. Here we review the current evidence for image-guided techniques with intensity-modulated radiotherapy to the prostate bed and describe current strategies to reduce or account for interfraction and intrafraction motion. Keywords: radiotherapy, prostate cancer, post-prostatectomy, image-guided radiation therapy

  5. Intensity Modulated Radiation Therapy With Dose Painting to Treat Rhabdomyosarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Joanna C.; Dharmarajan, Kavita V. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Wexler, Leonard H. [Department of Pediatrics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); La Quaglia, Michael P. [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Happersett, Laura [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Wolden, Suzanne L., E-mail: woldens@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2012-11-01

    Purpose: To examine local control and patterns of failure in rhabdomyosarcoma patients treated with intensity modulated radiation therapy (RT) with dose painting (DP-IMRT). Patients and Methods: A total of 41 patients underwent DP-IMRT with chemotherapy for definitive treatment. Nineteen also underwent surgery with or without intraoperative RT. Fifty-six percent had alveolar histologic features. The median interval from beginning chemotherapy to RT was 17 weeks (range, 4-25). Very young children who underwent second-look procedures with or without intraoperative RT received reduced doses of 24-36 Gy in 1.4-1.8-Gy fractions. Young adults received 50.4 Gy to the primary tumor and lower doses of 36 Gy in 1.8-Gy fractions to at-risk lymph node chains. Results: With 22 months of median follow-up, the actuarial local control rate was 90%. Patients aged {<=}7 years who received reduced overall and fractional doses had 100% local control, and young adults had 79% (P=.07) local control. Three local failures were identified in young adults whose primary target volumes had received 50.4 Gy in 1.8-Gy fractions. Conclusions: DP-IMRT with lower fractional and cumulative doses is feasible for very young children after second-look procedures with or without intraoperative RT. DP-IMRT is also feasible in adolescents and young adults with aggressive disease who would benefit from prophylactic RT to high-risk lymph node chains, although dose escalation might be warranted for improved local control. With limited follow-up, it appears that DP-IMRT produces local control rates comparable to those of sequential IMRT in patients with rhabdomyosarcoma.

  6. Nursing of Recurrent and Advanced Rectal Cancer Patients Receiving Concurrent XELOX Chemotherapy and Intensity Modulated Conformal Radiotherapy%XELOX方案同期化疗联合调强适形放疗治疗复发和局部晚期直肠癌的护理

    Institute of Scientific and Technical Information of China (English)

    陈世梅; 李莉

    2011-01-01

    Objective: To discuss the nursing methods of recurrent and locally advanced rectal cancer patients receiving concurrent XELOX regimen( Xeloda plus LOHP ) chemotherapy and intensity modulated conformal radiotherapy.Methods: Clinical records of 32 cases of recurrent and locally advanced rectal cancer accepting concurrent XELOX regimen chemotherapy and intensity modulated conformal radiotherapy were analyzed.Nursing procedures including pre-therapy psychological nursing was used before therapy,and suitable nursing measures were used during and after treatment.Results: The overall effective rate was 78.1% with 3 cases got CR and 22 PR.The main side-effects included nyelosuppression, neurotoxicity, hand-foot syndrome, nausea and vomiting, diarrhea,radiation proctitis, and cystitis.Conclusion: The concurrent XELOX regimen chemotherapy and intensity modulated conformal radiotherapy is proved effective in the treatment of recurrent and locally advanced rectal cancer.In order to accelerate the recovery of patients and improve their life qulities after chemoradiotherapy, appropriate nursing on the nutrition, skin, mouth, ostomy and psychological status of patients should be carried out to alleviate the side-effects.%目的:探讨卡培他滨(Xeloda,希罗达)联合奥沙利铂(LOHP)(XELOX方案)同期化疗联合调强适形放疗治疗复发和局部晚期直肠癌的临床护理.方法:对32例复发和局部晚期直肠癌患者XELOX方案同期化疗联合调强适形放疗的临床资料进行回顾性分析,治疗前采取心理护理,治疗期间及治疗后采取相应的护理措施.结果:本组32例患者中CR 3例,PR 22例,总有效率为78.1%.主要不良反应为骨髓抑制、神经系统毒性、手足综合征、恶心呕吐、腹泻、放射性直肠炎及膀胱炎等,但均无Ⅲ度-Ⅳ度毒副反应发生.结论:XELOX方案同期调强适形放疗治疗复发和局部晚期直肠癌配合有效的护理措施,能有效减轻放化疗的副反应,有

  7. Volumetric Modulated Arc Therapy, Conventional Intensity-modulated Radiotherapy and Three-Dimensional Conformal Techniques for Upper Thoracic Esophageal Cancer: A Planning Comparison Study%胸上段食管癌容积旋转调强和静态调强与三维适形放疗计划的剂量学比较

    Institute of Scientific and Technical Information of China (English)

    张瑞; 习勉; 李巧巧; 赵磊; 黄晓波; 何立儒; 胡永红; 刘孟忠

    2012-01-01

    [目的]比较容积旋转调强( VMAT)、静态调强(sIMRT)与三维适形放疗(3DCRT)技术在胸上段食管癌的剂量学差异.[方法]选取7例局部晚期胸上段食管癌患者,分别制定3DCRT、7野sIMRT和360度单弧VMAT 3套放疗计划,处方剂量统一为60 Gy/30F.比较靶区、危及器官的剂量体积参数,加速器的总机器跳数(MU)和有效治疗时间(TT)等.[结果]VMAT与IMRT的靶区剂量分布基本一致,均优于3DCRT.对于正常组织,三组计划中肺、心脏的受照剂量均无明显差异,但IMRT与VMAT可较3DCRT更好的保护脊髓.3DCRT、IMRT、VMAT的MU分别为537±92、601±122、682±139,有效治疗时间(min)分别为3.9±0.3、6.0±0.7、4.7±0.7 (P< 0.05).[结论]与3DCRT相比,VMAT与IMRT在胸上段食管癌均有一定的剂量学优势,但VMAT较IMRT可显著提高治疗效率.%[Objective] A planning study was performed to compare volumetric modulated arc therapy (VMAT), static intensity-modulated radiotherapy (sIMRT), and three-dimensional conformal radiotherapy (3DCRT) for upper thoracic esophageal cancer. [Methods] Seven patients with loco-regionally advanced upper thoracic esophageal cancer were included. Based on the identical CT and planning target volume (PTV), three plans (3DCRT, sIMRT with seven fields, VMAT with a single arc) were generated. Dose prescription was set to 60Gy in 30 fractions. Dose volume histograms, MU and delivery time were evaluated to assess plan quality. [Results] In comparison to 3DCRT, both VMAT and IMRT provided a systematic improvement in PTV coverage. For normal tissues, equivalent sparing of lung and heart were achieved with three plans. However, IMRT and VMAT showed a superior sparing compared with 3DCRT for spinal cord. The MU/fraction was as follows; 537 ± 92 for 3DCRT, 601 ± 122 for IMRT, and 682 ± 139 for VMAT. Effective treatment time for 3DCRT, IMRT and VMAT were (3.9 ± 0.3) min, (6.0 ± 0.7) min and (4.7 ± 0.7)min, respectively (P< 0

  8. Novel Immune-Modulating Cellular Vaccine for Prostate Cancer Immunotherapy

    Science.gov (United States)

    2015-10-01

    AWARD NUMBER: W81XWH-13-1-0423 TITLE: Novel Immune-Modulating Cellular Vaccine for Prostate Cancer Immunotherapy PRINCIPAL INVESTIGATOR: Smita...SUBTITLE 5a. CONTRACT NUMBER W81XWH-13-1-0423 Novel Immune-Modulating Cellular Vaccine for Prostate Cancer Immunotherapy 5b. GRANT NUMBER 5c...immune checkpoint blockade, local CTLA-4 modulation, prostate cancer immunotherapy , prostatic acid phosphatase (PAP), RNA-based vaccines 16

  9. Volumetric-Modulated Arc Therapy for Stereotactic Body Radiotherapy of Lung Tumors: A Comparison With Intensity-Modulated Radiotherapy Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Holt, Andrea; Vliet-Vroegindeweij, Corine van; Mans, Anton; Belderbos, Jose S. [Department of Radiation Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Damen, Eugene M.F., E-mail: e.damen@nki.nl [Department of Radiation Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands)

    2011-12-01

    Purpose: To demonstrate the potential of volumetric-modulated arc therapy (VMAT) compared with intensity-modulated radiotherapy (IMRT) techniques with a limited number of segments for stereotactic body radiotherapy (SBRT) for early-stage lung cancer. Methods and Materials: For a random selection of 27 patients eligible for SBRT, coplanar and noncoplanar IMRT and coplanar VMAT (using SmartArc) treatment plans were generated in Pinnacle{sup 3} and compared. In addition, film measurements were performed using an anthropomorphic phantom to evaluate the skin dose for the different treatment techniques. Results: Using VMAT, the delivery times could be reduced to an average of 6.6 min compared with 23.7 min with noncoplanar IMRT. The mean dose to the healthy lung was 4.1 Gy for VMAT and noncoplanar IMRT and 4.2 Gy for coplanar IMRT. The volume of healthy lung receiving >5 Gy and >20 Gy was 18.0% and 5.4% for VMAT, 18.5% and 5.0% for noncoplanar IMRT, and 19.4% and 5.7% for coplanar IMRT, respectively. The dose conformity at 100% and 50% of the prescribed dose of 54 Gy was 1.13 and 5.17 for VMAT, 1.11 and 4.80 for noncoplanar IMRT and 1.12 and 5.31 for coplanar IMRT, respectively. The measured skin doses were comparable for VMAT and noncoplanar IMRT and slightly greater for coplanar IMRT. Conclusions: Coplanar VMAT for SBRT for early-stage lung cancer achieved plan quality and skin dose levels comparable to those using noncoplanar IMRT and slightly better than those with coplanar IMRT. In addition, the delivery time could be reduced by {<=}70% with VMAT.

  10. Simple tool for prediction of parotid gland sparing in intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Gensheimer, Michael F. [Department of Radiation Oncology, University of Washington Medical Center, Seattle, WA (United States); Hummel-Kramer, Sharon M., E-mail: sharonhummel@comcast.net [Department of Radiation Oncology, VA Puget Sound Health Care System, Seattle, WA (United States); Cain, David; Quang, Tony S. [Department of Radiation Oncology, VA Puget Sound Health Care System, Seattle, WA (United States)

    2015-10-01

    Sparing one or both parotid glands is a key goal when planning head and neck cancer radiation treatment. If the planning target volume (PTV) overlaps one or both parotid glands substantially, it may not be possible to achieve adequate gland sparing. This finding results in physicians revising their PTV contours after an intensity-modulated radiation therapy (IMRT) plan has been run and reduces workflow efficiency. We devised a simple formula for predicting mean parotid gland dose from the overlap of the parotid gland and isotropically expanded PTV contours. We tested the tool using 44 patients from 2 institutions and found agreement between predicted and actual parotid gland doses (mean absolute error = 5.3 Gy). This simple method could increase treatment planning efficiency by improving the chance that the first plan presented to the physician will have optimal parotid gland sparing.

  11. Analysis of small-signal intensity modulation of semiconductor lasers taking account of gain suppression

    Indian Academy of Sciences (India)

    Moustafa Ahmed; Ali El-Lafi

    2008-07-01

    This paper demonstrates theoretical characterization of intensity modulation of semiconductor lasers (SL’s). The study is based on a small-signal model to solve the laser rate equations taking into account suppression of optical gain. Analytical forms of the small-signal modulation response and modulation bandwidth are derived. Influences of the bias current, modulation index and modulation frequency as well as gain suppression on modulation characteristics are examined. Computer simulation of the model is applied to 1.55-m InGaAsP lasers. The results show that when the SL is biased far-above threshold, the increase of gain suppression increases both the modulation response and its peak frequency. The modulation bandwidth also increases but the laser damping rate decreases. Quantitative description of the relationships of both modulation bandwidth vs. relaxation frequency and maximum modulation bandwidth vs. nonlinear gain coefficient are presented.

  12. Exercise-induced endocannabinoid signaling is modulated by intensity.

    Science.gov (United States)

    Raichlen, David A; Foster, Adam D; Seillier, Alexandre; Giuffrida, Andrea; Gerdeman, Gregory L

    2013-04-01

    Endocannabinoids (eCB) are endogenous ligands for cannabinoid receptors that are densely expressed in brain networks responsible for reward. Recent work shows that exercise activates the eCB system in humans and other mammals, suggesting eCBs are partly responsible for the reported improvements in mood and affect following aerobic exercise in humans. However, exercise-induced psychological changes reported by runners are known to be dependent on exercise intensity, suggesting that any underlying molecular mechanism should also change with varying levels of exercise intensity. Here, we examine circulating levels of eCBs following aerobic exercise (treadmill running) in recreationally fit human runners at four different intensities. We show that eCB signaling is indeed intensity dependent, with significant changes in circulating eCBs observed following moderate intensities only (very high and very low intensity exercises do not significantly alter circulating eCB levels). Our results are consistent with intensity-dependent psychological state changes with exercise and therefore support the hypothesis that eCB activity is related to neurobiological effects of exercise. Thus, future studies examining the role of exercise-induced eCB signaling on neurobiology or physiology must take exercise intensity into account.

  13. 直肠癌术前容积旋转调强放疗和五野静态调强放疗的剂量学比较%Dosimetric comparison between preoperative volumetric modulated arc therapy and five-field intensity modulated radiotherapy for rectal cancer

    Institute of Scientific and Technical Information of China (English)

    汪琳; 张红雁; 钱立庭; 吴爱东; 方为; 闫冰

    2016-01-01

    目的:比较直肠癌术前患者应用五野静态调强放疗(5F-IMRT)和容积弧形调强放疗( VMAT)两种计划的剂量学差别。方法分别将16例术前行同期放化疗的直肠癌患者进行5F-IMRT和VMAT两种计划设计,应用剂量体积直方图比较分析靶区和危及器官的剂量学差异及治疗参数。结果两种治疗计划均能满足临床剂量要求。5F-IMRT计划的适形指数(CI)为0.88±0.04,VMAT计划的CI为0.90±0.03,两种计划均能很好满足95%等剂量曲线对100%PTV体积的完全覆盖;VMAT 和 IMRT 计划的均匀性指数(HI)分别为1.06±0.01和1.05±0.01,差异无统计学意义(t=1.37,P>0.05)。5F-IMRT和VMAT计划中重要的危及器官如小肠、膀胱和股骨头等的关键剂量评价指标( Dmean、Dmax)及受照射体积的关键评价指标( V20、V30、V40和V50)在两种放疗计划中差异无统计学意义( P >0.05)。VMAT计划组较5F-IMRT计划组机器跳数( MU)平均值减少39%(P=0.000)。结论直肠癌术前放疗中采用VMAT技术可获得等同于5F-IMRT计划的剂量分布,危及器官均能得到较好的保护, VMAT计划MU明显降低,治疗时间明显缩短。%Objective To compare the dosimetric characteristics of volumetric modulated arc therapy( VMAT) and five-field intensity modulated radiotherapy(5F-IMRT) in preoperative radiotherapy for rectal cancer. Methods Six-teen patients with rectal cancer who underwent preoperative chemo-radiotherapy were enrolled in this study. VMAT and 5F-IMRT plans were designed for each patient. The dose distribution in target volumes and organs at risk was e-valuated according to the dose-volume histogram. Results Both plans could meet target dose specifications and nor-mal tissue constraint. The CI was similar between the 5F-IMRT(0. 88 ± 0. 04) and VMAT plans (0. 90 ± 0. 03), which could satisfy 95% of prescribed dose for covered PTV. The HI of the VMAT plan was 1. 06 ± 0. 01 compared to 1. 05 ± 0. 01

  14. Influences of Modulated Noise on Normalized Intensity Fluctuation in a Single-Mode Laser

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; CAO Li; WU Da-Jin

    2004-01-01

    @@ The influences of the two forms of modulated noises, i.e. the bias signal-modulated noise and the direct signalmodulated noise, on the normalized intensity fluctuation (NIF) are investigated, and the results of the two forms of modulation are compared in detail. We find that a minimum for the case of the bias signal modulation appears in the curve of the dependence of the NIF upon the quantum and pump noise intensities when the correlation coefficient between the quantum noise and the pump noise is negative. However, the NIF for the case of the direct signal modulation is independent of the correlation coefficient between the two noises. Moreover, at the same parameter region, the NIF for the bias signal modulation is only one-eighth as much as that for the direct signal modulation.

  15. Organisational standards for the delivery of intensity-modulated radiation therapy in Ontario.

    Science.gov (United States)

    Whitton, A; Warde, P; Sharpe, M; Oliver, T K; Bak, K; Leszczynski, K; Etheridge, S; Fleming, K; Gutierrez, E; Favell, L; Green, E

    2009-04-01

    By minimising the effect of irradiation on surrounding tissue, intensity-modulated radiation therapy (IMRT) can deliver higher, more effective doses to the targeted tumour site, minimising treatment-related morbidity and possibly improving cancer control and cure. A multidisciplinary IMRT Expert Panel was convened to develop the organisational standards for the delivery of IMRT. The systematic literature search used MEDLINE, EMBASE, the Cochrane Database, the National Guidelines Clearing House and the Health Technology Assessment Database. An environmental scan of unpublished literature used the Google search engine to review the websites of key organisations, cancer agencies/centres and vendor sites in Canada, the USA, Australia and Europe. In total, 22 relevant guidance documents were identified; 12 from the published literature and 10 from the environmental scan. Professional and organisational standards for the provision of IMRT were developed through the analysis of this evidence and the consensus opinion of the IMRT Expert Panel. The resulting standards address the following domains: planning of new IMRT programmes, practice setting requirements, tools, devices and equipment requirements; professional training requirements; role of personnel; and requirements for quality assurance and safety. Here the IMRT Expert Panel offers organisational and professional standards for the delivery of IMRT, with the intent of promoting innovation, improving access and enhancing patient care.

  16. Ultra-fine metal gate operated graphene optical intensity modulator

    Science.gov (United States)

    Kou, Rai; Hori, Yosuke; Tsuchizawa, Tai; Warabi, Kaori; Kobayashi, Yuzuki; Harada, Yuichi; Hibino, Hiroki; Yamamoto, Tsuyoshi; Nakajima, Hirochika; Yamada, Koji

    2016-12-01

    A graphene based top-gate optical modulator on a standard silicon photonic platform is proposed for the future optical telecommunication networks. On the basis of the device simulation, we proposed that an electro-absorption light modulation can be realized by an ultra-narrow metal top-gate electrode (width less than 400 nm) directly located on the top of a silicon wire waveguide. The designed structure also provides excellent features such as carrier doping and waveguide-planarization free fabrication processes. In terms of the fabrication, we established transferring of a CVD-grown mono-layer graphene sheet onto a CMOS compatible silicon photonic sample followed by a 25-nm thick ALD-grown Al2O3 deposition and Source-Gate-Drain electrodes formation. In addition, a pair of low-loss spot-size converter for the input and output area is integrated for the efficient light source coupling. The maximum modulation depth of over 30% (1.2 dB) is observed at a device length of 50 μm, and a metal width of 300 nm. The influence of the initial Fermi energy obtained by experiment on the modulation performance is discussed with simulation results.

  17. Dosimetric comparison between volumetric modulated arc therapy and fixed-gantry dynamic intensity modulated radiation therapy for rectal cancer radiotherapy%直肠癌旋转容积调强与固定野动态调强的剂量学比较

    Institute of Scientific and Technical Information of China (English)

    花威; 李军; 谭飞; 陈婷婷; 汪步海

    2012-01-01

    目的:比较旋转容积调强(VMAT)与固定野动态调强(dIMRT)在直肠癌放疗计划中的剂量学差异.方法:8例直肠癌患者利用瓦里安计划系统(Eclipse 8.6)分别进行VMAT和dIMRT放射治疗计划设计.利用剂量体积直方图来比较两种计划中靶区和危及器官的剂量学差异.结果:与dIMRT相比,VMAT靶区适合度指数(CI)、靶区剂量均匀性指数(HI)均更接近1,Dmin为(43.403±0.486)Gy,更接近处方剂量,差异有统计学意义,P<0.05.在VMAT计划中小肠的D30%、D50%和Dmean分别为(25.918±1.216)、(22.340士3.784)和(23.547±2.863) Gy,低于dIMRT计划的(28.073±3.114)、(24.172±2.540)和(25.257±1.374) Gy,P值分别为0.00、0.01和0.00;膀胱的D30%为(35.380±2.734) Gy,较dIMRT的(30.123±2.209) Gy偏高,P=0.00,但仍远低于剂量限值;股骨头的D5%和Dmean分别为(31.344±3.556)和(20.179±3.017) Gy,显著高于dIMRT计划的(26.731±2.828)和(17.459±3.279) Gy,P值均为0.00.VMAT总MU减少52.7%,治疗时间仅为dIMRT的1/4.结论:VMAT计划可以达到或优于dIMRT计划的靶区剂量分布,能更好地降低部分危及器官的受照剂量,并且具有较少总MU、总治疗时间的优势,减少了治疗中不确定性因素的影响及患者不适感.%OBJECTIVE: To compare the dosimetric difference between volumetric modulated arc therapy(VMAT) and fixed-gantry dynamic intensity modulated radiation therapy(dIMRT) for rectal cancer. METHODS: VMAT and dlM-RT treatment plans of 8 rectal cancer cases were generated by Vrian Eclipse ver8. 6 treatment planning systerm. Dose volume histograms were used to compare the target volume and organs at risks. RESULTS: Compared to dIMRT,conformity index(CI) and homogeneity index(HI) of VMAT closer to one. Dmin of VMAT was (43. 403 ± 0. 486) Gy,closer to prescription dose. There were significant differences in CI,HI and Dmin(P<0. 05). The small intestinal's D30% ,D50% and Dmean were larger in dIMRT than those in VAMT(P values were

  18. 直肠癌术前五野静态调强和容积弧形调强放疗剂量学的比较研究%Dosimetric comparison between preoperative five-field intensity modulated radiotherapy and volumetric modulated arc therapy in the treatment of rectum cancer

    Institute of Scientific and Technical Information of China (English)

    叶序卷; 高远红; 陈利; 杜乐辉; 张广顺; 贾钰铭; 雷开键; 刘孟忠

    2012-01-01

    目的 探讨直肠癌术前五野静态调强(5 F-IMRT)和容积弧形调强(VMAT)放疗计划的剂量学特点.方法 应用CMS monaco治疗计划系统分别对23例术前同期放化疗的直肠癌患者行5F-IMRT和VMAT放疗计划设计,比较两种放疗技术的靶区剂量分布特点以及小肠、膀胱、双侧股骨头等正常组织的受照射剂量及体积.结果 5F-IMRT计划的适形指数(CI)为0.810±0.043,VMAT计划的CI为0.822±0.062,两者均能很好满足95%等剂量曲线对100% PTV体积的完全覆盖;5F-IMRT计划中GTV、CTV和PTV的均匀指数(HI)分别为1.052±0.019、1.063±0.016、1.075±0.020,VMAT计划分别为1.037±0.008、1.047 ±0.008、1.072±0.018,差异均无统计学意义.5F-IMRT和 VMAT计划中重耍的危及器官如小肠、膀胱和股骨头等的关键剂量评价指标(D5、Dmin、Dmean和Dmax)差异均无统计学意义(P>0.05).小肠、膀胱和股骨头等受照射体积的关键评价指标(V20、V30、V40和V50)在两种放疗计划中差异均无统计学意义(P>0.05).结论 5F-IMRT和VMAT计划靶区的剂量分布均较理想,对小肠、膀胱、双侧股骨头等正常组织均有很好的保护作用.%Objective To investigate the dosimetric comparison between prenperalive live-field intensity modulated radiotherapy (5F-IMRT) and volumetric modulated arc therapy ( VMAT) in the. rectum cancer patients with concurrent chemotherapy and radiotherapy. Methods With the application of CMS monaco syslems( V2. 0,Sweden) , 5F-IMRT and VMAT plans were simulated in 23 rectum cancer patients with preoperative concurrent chemoradlotherapy. The dose characteristic of target volume was evaluated and the dose-volume relationship of small bowel, bladder and bilateral femoral head was compared. Results The CI was similar between the 5F-IMRT(0. 810 ±0. 043) and VMAT plans(0. 822 ±0. 062) , which could satisfy 95% of prescribed dose for covered PTV. The HI of the prescribed dose to GTV( 1. 052 ±0. 019 vs. 1

  19. Identifying module biomarkers from gastric cancer by differential correlation network

    Directory of Open Access Journals (Sweden)

    Liu X

    2016-09-01

    Full Text Available Xiaoping Liu,1–3,* Xiao Chang1,3,* 1College of Statistics and Applied Mathematics, Anhui University of Finance and Economics, Bengbu, Anhui Province, People’s Republic of China; 2Key Laboratory of Systems Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, People’s Republic of China; 3Collaborative Research Center for Innovative Mathematical Modeling, Institute of Industrial Science, University of Tokyo, Tokyo, Japan *These authors contributed equally to this work Abstract: Gastric cancer (stomach cancer is a severe disease caused by dysregulation of many functionally correlated genes or pathways instead of the mutation of individual genes. Systematic identification of gastric cancer biomarkers can provide insights into the mechanisms underlying this deadly disease and help in the development of new drugs. In this paper, we present a novel network-based approach to predict module biomarkers of gastric cancer that can effectively distinguish the disease from normal samples. Specifically, by assuming that gastric cancer has mainly resulted from dysfunction of biomolecular networks rather than individual genes in an organism, the genes in the module biomarkers are potentially related to gastric cancer. Finally, we identified a module biomarker with 27 genes, and by comparing the module biomarker with known gastric cancer biomarkers, we found that our module biomarker exhibited a greater ability to diagnose the samples with gastric cancer. Keywords: biomarkers, gastric cancer, stomach cancer, differential network

  20. Direct UV written Michelson interferometer for RZ signal generation using phase-to-intensity modulation conversion

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Geng, Yan; Zsigri, Beata

    2005-01-01

    An integrated Michelson delay interferometer structure making use of waveguide gratings as reflective elements is proposed and fabricated by direct ultraviolet writing. Successful return-to-zero alternate-mark-inversion signal generation using phase-to-intensity modulation conversion...

  1. Intensity modulation in single-mode microchip Nd:YAG lasers with asymmetric external cavity

    Institute of Scientific and Technical Information of China (English)

    Tan Yi-Dong; Zhang Shu-Lian; Liu Wei-Xin; Mao Wei

    2007-01-01

    Intensity modulation induced by the asymmetric external cavity in single-mode microchip Nd:YAG lasers is presented. Two kinds of experimental results are discussed based on multiple feedback effects. In one case, the intensity modulation curve is a normal sine wave, whose fringe frequency is four times higher than that of a conventional optical feedback system, caused by multiple feedback effects. In the other case, the intensity modulation curve is the overlapping of the above quadruple-frequency signal and conventional optical feedback signal, which is determined by the additional phase difference induced by the asymmetric external cavity. The theoretical analyses are in good agreement with the experimental results. The quadruple-frequency modulation of the laser output intensity can greatly increase the resolution of displacement measurement of an optical feedback system.

  2. Patient Specification Quality Assurance for Glioblastoma Multiforme Brain Tumors Treated with Intensity Modulated Radiation Therapy

    OpenAIRE

    Al-Mohammed, H. I.

    2011-01-01

    The aim of this study was to evaluate the significance of performing patient specification quality assurance for patients diagnosed with glioblastoma multiforme treated with intensity modulated radiation therapy. The study evaluated ten intensity modulated radiation therapy treatment plans using 10 MV beams, a total dose of 60 Gy (2 Gy/fraction, five fractions a week for a total of six weeks treatment). For the quality assurance protocol we used a two-dimensional ionization-chamber array (2D-...

  3. Modulation of ionization on laser frequency in ultra-short pulse intense laser-gas-target

    Institute of Scientific and Technical Information of China (English)

    Hu Qiang-Lin; Liu Shi-Bing

    2006-01-01

    Based on the dispersion relation of intense laser pulse propagating in gradually ionized plasma, this paper discusses the frequency modulation induced by ionization of an ultra-short intense laser pulse interacting with a gas target.The relationship between the frequency modulation and the ionization rate, the plasmas frequency variation, and the polarization of atoms (ions) is analysed. The numerical results indicate that, at high frequency, the polarization of atoms (ions) plays a more important role than plasma frequency variation in modulating the laser frequency, and the laser frequency variation is different at different positions of the laser pulse.

  4. Modulation Depth Based on Frequency-shift Characteristic of LiNbO3 Waveguide Electro-optic Intensity Modulator

    Institute of Scientific and Technical Information of China (English)

    Hui-juan ZHOU; Zhou MENG; Yi LIAO

    2010-01-01

    The modulation depth,defined according to practical mod-ulation results,which changes with the microwave power and its fre-quency,is significant for systems utilizing the frequency-shift charac-teristic of the LiNbO3 waveguide Electro-Optic Intensity Modulator (EOIM).By analyzing the impedance mismatch between the micro-wave source and the EOIM,the effective voltage applied to the RF port of the EOIM is deprived frcm the microwave power and its fre-quency.Associating with analyses of the phase velocity mismatch be-tween the microwave and the optical wave,the theoretical modulation depth has been obtained,which is verified by experimental results.We provide a method to choose the appropriate modulation depth to optimize the desired sideband through proper transmission bias far the system based an the frequency-shift characteristic of the EOIM.

  5. The clinical potential of high energy, intensity and energy modulated electron beams optimized by simulated annealing for conformal radiation therapy

    Science.gov (United States)

    Salter, Bill Jean, Jr.

    Purpose. The advent of new, so called IVth Generation, external beam radiation therapy treatment machines (e.g. Scanditronix' MM50 Racetrack Microtron) has raised the question of how the capabilities of these new machines might be exploited to produce extremely conformal dose distributions. Such machines possess the ability to produce electron energies as high as 50 MeV and, due to their scanned beam delivery of electron treatments, to modulate intensity and even energy, within a broad field. Materials and methods. Two patients with 'challenging' tumor geometries were selected from the patient archives of the Cancer Therapy and Research Center (CTRC), in San Antonio Texas. The treatment scheme that was tested allowed for twelve, energy and intensity modulated beams, equi-spaced about the patient-only intensity was modulated for the photon treatment. The elementary beams, incident from any of the twelve allowed directions, were assumed parallel, and the elementary electron beams were modeled by elementary beam data. The optimal arrangement of elementary beam energies and/or intensities was optimized by Szu-Hartley Fast Simulated Annealing Optimization. Optimized treatment plans were determined for each patient using both the high energy, intensity and energy modulated electron (HIEME) modality, and the 6 MV photon modality. The 'quality' of rival plans were scored using three different, popular objective functions which included Root Mean Square (RMS), Maximize Dose Subject to Dose and Volume Limitations (MDVL - Morrill et. al.), and Probability of Uncomplicated Tumor Control (PUTC) methods. The scores of the two optimized treatments (i.e. HIEME and intensity modulated photons) were compared to the score of the conventional plan with which the patient was actually treated. Results. The first patient evaluated presented a deeply located target volume, partially surrounding the spinal cord. A healthy right kidney was immediately adjacent to the tumor volume, separated

  6. Nanobiotechnology promotes noninvasive high-intensity focused ultrasound cancer surgery.

    Science.gov (United States)

    Chen, Yu; Chen, Hangrong; Shi, Jianlin

    2015-01-07

    The successful cancer eradication in a noninvasive manner is the ultimate objective in the fight against cancer. As a "bloodless scalpel," high-intensity focused ultrasound (HIFU) is regarded as one of the most promising and representative noninvasive therapeutic modalities for cancer surgery. However, large-scale clinical applications of HIFU are still in their infancy because of critical efficiency and safety issues which remain to be solved. Fortunately, recently developed nanobiotechnology provides an alternative efficient approach to improve such important issues in HIFU, especially for cancer therapy. This Research News presents the very recent exciting progresses on the elaborate design and fabrication of organic, inorganic, and organic/inorganic hybrid nanoparticles for enhancing the HIFU ablation efficiency against tumor tissues. It is highly expected that this Research News can arouse more extensive research enthusiasm on the development of functional nanomaterials for highly efficient HIFU-based synergistic therapy, which will give a promising noninvasive therapeutic modality for the successful cancer therapy with minimal damage to surrounding normal tissues, due to the noninvasive and site-specific therapeutic features of HIFU.

  7. Markov modulated Poisson process models incorporating covariates for rainfall intensity.

    Science.gov (United States)

    Thayakaran, R; Ramesh, N I

    2013-01-01

    Time series of rainfall bucket tip times at the Beaufort Park station, Bracknell, in the UK are modelled by a class of Markov modulated Poisson processes (MMPP) which may be thought of as a generalization of the Poisson process. Our main focus in this paper is to investigate the effects of including covariate information into the MMPP model framework on statistical properties. In particular, we look at three types of time-varying covariates namely temperature, sea level pressure, and relative humidity that are thought to be affecting the rainfall arrival process. Maximum likelihood estimation is used to obtain the parameter estimates, and likelihood ratio tests are employed in model comparison. Simulated data from the fitted model are used to make statistical inferences about the accumulated rainfall in the discrete time interval. Variability of the daily Poisson arrival rates is studied.

  8. Risk of second malignant neoplasm following proton versus intensity-modulated photon radiotherapies for hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Taddei, Phillip J; Howell, Rebecca M; Krishnan, Sunil; Scarboro, Sarah B; Mirkovic, Dragan; Newhauser, Wayne D, E-mail: ptaddei@mdanderson.or [Division of Radiation Oncology, Unit 1202, University of Texas M D Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030 (United States)

    2010-12-07

    Hepatocellular carcinoma (HCC), the sixth most common cancer in the world, is a global health concern. Radiotherapy for HCC is uncommon, largely because of the likelihood of radiation-induced liver disease, an acute side effect that is often fatal. Proton beam therapy (PBT) and intensity-modulated radiation therapy (IMRT) may offer HCC patients a better option for treating the diseased liver tissue while largely sparing the surrounding tissues, especially the non-tumor liver. However, even advanced radiotherapies carry a risk of late effects, including second malignant neoplasms (SMNs). It is unclear whether PBT or IMRT confers less risk of an SMN than the other. The purpose of this study was to compare the predicted risk of developing an SMN for a patient with HCC between PBT and IMRT. For both treatments, radiation doses in organs and tissues from primary radiation were determined using a treatment planning system; doses in organs and tissues from stray radiation from PBT were determined using Monte Carlo simulations and from IMRT using thermo-luminescent dosimeter measurements. Risk models of SMN incidence were taken from the literature. The predicted absolute lifetime attributable risks of SMN incidence were 11.4% after PBT and 19.2% after IMRT. The results of this study suggest that using proton beams instead of photon beams for radiotherapy may reduce the risk of SMN incidence for some HCC patients.

  9. Risk of second malignant neoplasm following proton versus intensity-modulated photon radiotherapies for hepatocellular carcinoma

    Science.gov (United States)

    Taddei, Phillip J.; Howell, Rebecca M.; Krishnan, Sunil; Scarboro, Sarah B.; Mirkovic, Dragan; Newhauser, Wayne D.

    2010-12-01

    Hepatocellular carcinoma (HCC), the sixth most common cancer in the world, is a global health concern. Radiotherapy for HCC is uncommon, largely because of the likelihood of radiation-induced liver disease, an acute side effect that is often fatal. Proton beam therapy (PBT) and intensity-modulated radiation therapy (IMRT) may offer HCC patients a better option for treating the diseased liver tissue while largely sparing the surrounding tissues, especially the non-tumor liver. However, even advanced radiotherapies carry a risk of late effects, including second malignant neoplasms (SMNs). It is unclear whether PBT or IMRT confers less risk of an SMN than the other. The purpose of this study was to compare the predicted risk of developing an SMN for a patient with HCC between PBT and IMRT. For both treatments, radiation doses in organs and tissues from primary radiation were determined using a treatment planning system; doses in organs and tissues from stray radiation from PBT were determined using Monte Carlo simulations and from IMRT using thermo-luminescent dosimeter measurements. Risk models of SMN incidence were taken from the literature. The predicted absolute lifetime attributable risks of SMN incidence were 11.4% after PBT and 19.2% after IMRT. The results of this study suggest that using proton beams instead of photon beams for radiotherapy may reduce the risk of SMN incidence for some HCC patients.

  10. Analysis of Factors Influencing the Development of Xerostomia during Intensity-Modulated Radiotherapy

    Science.gov (United States)

    Randall, Ken; Stevens, Jason; Yepes, Juan Fernando; Randall, Marcus E.; Kudrimoti, Mahesh; Feddock, Jonathan; Xi, Jing; Kryscio, Richard J.; Miller, Craig S.

    2013-01-01

    OBJECTIVES Factors influencing xerostomia during intensity-modulated radiation therapy (IMRT) were assessed. METHODS A 6-week study of 32 head and neck cancer (HNC) patients was performed. Subjects completed the Xerostomia Inventory (XI) and provided stimulated saliva (SS) at baseline, week two and at end of IMRT. Influence of SS flow rate (SSFR), calcium and mucin 5b (MUC5b) concentrations and radiation dose on xerostomia was determined. RESULTS HNC subjects experienced mean SSFR decline of 36% by visit two (N=27; p=0.012) and 57% by visit three (N=20; p=0.0004), Concentrations of calcium and MUC5b increased, but not significantly during IMRT (p>0.05). Xerostomia correlated most with decreasing salivary flow rate as determined by Spearman correlations (p<0.04) and linear mixed models (p<0.0001). CONCLUSIONS Although IMRT is sparing to the parotid glands, it has an early effect on SSFR and the constituents in saliva in a manner that is associated with the perception of xerostomia. PMID:23523462

  11. Patient Specification Quality Assurance for Glioblastoma Multiforme Brain Tumors Treated with Intensity Modulated Radiation Therapy

    Directory of Open Access Journals (Sweden)

    H. I. Al-Mohammed

    2011-01-01

    Full Text Available The aim of this study was to evaluate the significance of performing patient specification quality assurance for patients diagnosed with glioblastoma multiforme treated with intensity modulated radiation therapy. The study evaluated ten intensity modulated radiation therapy treatment plans using 10 MV beams, a total dose of 60 Gy (2 Gy/fraction, five fractions a week for a total of six weeks treatment. For the quality assurance protocol we used a two-dimensional ionization-chamber array (2D-ARRAY. The results showed a very good agreement between the measured dose and the pretreatment planned dose. All the plans passed >95% gamma criterion with pixels within 5% dose difference and 3 mm distance to agreement. We concluded that using the 2D-ARRAY ion chamber for intensity modulated radiation therapy is an important step for intensity modulated radiation therapy treatment plans, and this study has shown that our treatment planning for intensity modulated radiation therapy is accurately done.

  12. Kilovoltage Intrafraction Monitoring for Prostate Intensity Modulated Arc Therapy: First Clinical Results

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Jin Aun [Radiation Physics Laboratory, Sydney Medical School and Institute of Medical Physics, School of Physics, University of Sydney, New South Wales (Australia); Institute of Medical Physics, School of Physics, University of Sydney, New South Wales (Australia); Booth, Jeremy T. [Institute of Medical Physics, School of Physics, University of Sydney, New South Wales (Australia); Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales (Australia); Poulsen, Per R.; Fledelius, Walther; Worm, Esben Schjodt [Department of Oncology, Aarhus University Hospital, Denmark, and Institute of Clinical Medicine, Aarhus University (Denmark); Eade, Thomas; Hegi, Fiona; Kneebone, Andrew [Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales (Australia); Kuncic, Zdenka [Institute of Medical Physics, School of Physics, University of Sydney, New South Wales (Australia); Keall, Paul J., E-mail: paul.keall@sydney.edu.au [Radiation Physics Laboratory, Sydney Medical School and Institute of Medical Physics, School of Physics, University of Sydney, New South Wales (Australia)

    2012-12-01

    Purpose: Most linear accelerators purchased today are equipped with a gantry-mounted kilovoltage X-ray imager which is typically used for patient imaging prior to therapy. A novel application of the X-ray system is kilovoltage intrafraction monitoring (KIM), in which the 3-dimensional (3D) tumor position is determined during treatment. In this paper, we report on the first use of KIM in a prospective clinical study of prostate cancer patients undergoing intensity modulated arc therapy (IMAT). Methods and Materials: Ten prostate cancer patients with implanted fiducial markers undergoing conventionally fractionated IMAT (RapidArc) were enrolled in an ethics-approved study of KIM. KIM involves acquiring kV images as the gantry rotates around the patient during treatment. Post-treatment, markers in these images were segmented to obtain 2D positions. From the 2D positions, a maximum likelihood estimation of a probability density function was used to obtain 3D prostate trajectories. The trajectories were analyzed to determine the motion type and the percentage of time the prostate was displaced {>=}3, 5, 7, and 10 mm. Independent verification of KIM positional accuracy was performed using kV/MV triangulation. Results: KIM was performed for 268 fractions. Various prostate trajectories were observed (ie, continuous target drift, transient excursion, stable target position, persistent excursion, high-frequency excursions, and erratic behavior). For all patients, 3D displacements of {>=}3, 5, 7, and 10 mm were observed 5.6%, 2.2%, 0.7% and 0.4% of the time, respectively. The average systematic accuracy of KIM was measured at 0.46 mm. Conclusions: KIM for prostate IMAT was successfully implemented clinically for the first time. Key advantages of this method are (1) submillimeter accuracy, (2) widespread applicability, and (3) a low barrier to clinical implementation. A disadvantage is that KIM delivers additional imaging dose to the patient.

  13. First dose-map measured with a polycrystalline diamond 2D dosimeter under an intensity modulated radiotherapy beam

    Energy Technology Data Exchange (ETDEWEB)

    Scaringella, M., E-mail: scaringella@gmail.com [Università di Firenze, Dipartimento di Ingegneria dell’Informazione, Firenze (Italy); Zani, M. [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Scienze Biomediche, Sperimentali e Cliniche, Firenze (Italy); Baldi, A. [Università di Firenze, Dipartimento di Ingegneria Industriale, Firenze (Italy); Bucciolini, M. [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Scienze Biomediche, Sperimentali e Cliniche, Firenze (Italy); Pace, E.; Sio, A. de [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Fisica e Astronomia, Sesto Fiorentino, Firenze (Italy); Talamonti, C. [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Scienze Biomediche, Sperimentali e Cliniche, Firenze (Italy); Bruzzi, M. [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Fisica e Astronomia, Sesto Fiorentino, Firenze (Italy)

    2015-10-01

    A prototype of bidimensional dosimeter made on a 2.5×2.5 cm{sup 2} active area polycrystalline Chemical Vapour Deposited (pCVD) diamond film, equipped with a matrix of 12×12 contacts connected to the read-out electronics, has been used to evaluate a map of dose under Intensity Modulated Radiation Therapy (IMRT) fields for a possible application in pre-treatment verifications of cancer treatments. Tests have been performed under a 6–10 MVRX beams with IMRT fields for prostate and breast cancer. Measurements have been taken by measuring the 144 pixels in different positions, obtained by shifting the device along the x/y axes to span a total map of 14.4×10 cm{sup 2}. Results show that absorbed doses measured by our pCVD diamond device are consistent with those calculated by the Treatment Planning System (TPS)

  14. Development of a Standardized Method for Contouring the Lumbosacral Plexus: A Preliminary Dosimetric Analysis of this Organ at Risk Among 15 Patients Treated With Intensity-Modulated Radiotherapy for Lower Gastrointestinal Cancers and the Incidence of Radiation-Induced Lumbosacral Plexopathy

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Sun K., E-mail: sun.yi@ucdmc.ucdavis.edu [Department of Radiation Oncology, University of California, Davis Cancer Center, Sacramento, CA (United States); Mak, Walter [Department of Radiology, University of California, Davis Medical Center, Sacramento, CA (United States); Yang, Claus C.; Liu Tianxiao [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS (United States); Cui Jing; Chen, Allen M.; Purdy, James A.; Monjazeb, Arta M. [Department of Radiation Oncology, University of California, Davis Cancer Center, Sacramento, CA (United States); Do, Ly [Cancer Care Institute, San Jose, CA (United States)

    2012-10-01

    Purpose: To generate a reproducible step-wise guideline for the delineation of the lumbosacral plexus (LSP) on axial computed tomography (CT) planning images and to provide a preliminary dosimetric analysis on 15 representative patients with rectal or anal cancers treated with an intensity-modulated radiotherapy (IMRT) technique. Methods and Materials: A standardized method for contouring the LSP on axial CT images was devised. The LSP was referenced to identifiable anatomic structures from the L4-5 interspace to the level of the sciatic nerve. It was then contoured retrospectively on 15 patients treated with IMRT for rectal or anal cancer. No dose limitations were placed on this organ at risk during initial treatment planning. Dosimetric parameters were evaluated. The incidence of radiation-induced lumbosacral plexopathy (RILSP) was calculated. Results: Total prescribed dose to 95% of the planned target volume ranged from 50.4 to 59.4 Gy (median 54 Gy). The mean ({+-}standard deviation [SD]) LSP volume for the 15 patients was 100 {+-} 22 cm{sup 3} (range, 71-138 cm{sup 3}). The mean maximal dose to the LSP was 52.6 {+-} 3.9 Gy (range, 44.5-58.6 Gy). The mean irradiated volumes of the LSP were V40Gy = 58% {+-} 19%, V50Gy = 22% {+-} 23%, and V55Gy = 0.5% {+-} 0.9%. One patient (7%) was found to have developed RILSP at 13 months after treatment. Conclusions: The true incidence of RILSP in the literature is likely underreported and is not a toxicity commonly assessed by radiation oncologists. In our analysis the LSP commonly received doses approaching the prescribed target dose, and 1 patient developed RILSP. Identification of the LSP during IMRT planning may reduce RILSP. We have provided a reproducible method for delineation of the LSP on CT images and a preliminary dosimetric analysis for potential future dose constraints.

  15. Intensity-modulated radiotherapy for early-stage breast cancer after breast-conserving surgery%早期乳腺癌保乳术后调强适形放疗的应用

    Institute of Scientific and Technical Information of China (English)

    冶秀鹏

    2010-01-01

    传统的保乳术后放疗方法是做全乳腺照射5~6周,引起的不良反应多见.随着放射治疗技术的发展,以最小的侵袭或损伤达到最佳疗效,已成为肿瘤学者追求的目标.调强适形放疗(IMRT)的发展有很大的空间,日益受到广大学者的重视,将可能会成为早期乳腺癌保乳术后的标准治疗方式.%Conventional radiotherapy after breast-conserving surgery is generally delivered to the overall breast over a period of 5 to 6 weeks,but its negative effects are significant.With the development of radiotherapy techniques,achieving optimal curative effect with least invasion becomes the researchers aims.Intensitymodulated radiotherapy(IMRT) has come to the forefront as a potential alternative.IMRT attracts more and more attention ,and has a promising perspect.IMRT may become the standard treatment for early-stage breast cancer after breast conservation treatment.

  16. Intensity Modulated Proton Beam Radiation for Brachytherapy in Patients With Cervical Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Clivio, Alessandro [Oncology Institute of Southern Switzerland, Bellinzona (Switzerland); Kluge, Anne [Department of Radiation Oncology, Charité University Hospital, Berlin (Germany); Cozzi, Luca, E-mail: lucozzi@iosi.ch [Oncology Institute of Southern Switzerland, Bellinzona (Switzerland); Köhler, Christhardt [Department of Gynecology, Charité University Hospital, Berlin (Germany); Neumann, Oliver [Department of Radiation Oncology, Charité University Hospital, Berlin (Germany); Vanetti, Eugenio [Oncology Institute of Southern Switzerland, Bellinzona (Switzerland); Wlodarczyk, Waldemar; Marnitz, Simone [Department of Radiation Oncology, Charité University Hospital, Berlin (Germany)

    2013-12-01

    Purpose: To evaluate intensity modulated proton therapy (IMPT) in patients with cervical cancer in terms of coverage, conformity, and dose–volume histogram (DVH) parameters correlated with recommendations from magnetic resonance imaging (MRI)-guided brachytherapy. Methods and Materials: Eleven patients with histologically proven cervical cancer underwent primary chemoradiation for the pelvic lymph nodes, the uterus, the cervix, and the parametric region, with a symmetric margin of 1 cm. The prescription was for 50.4 Gy, with 1.8 Gy per fraction. The prescribed dose to the parametria was 2.12 Gy up to 59.36 Gy in 28 fractions as a simultaneous boost. For several reasons, the patients were unable to undergo brachytherapy. As an alternative, IMPT was planned with 5 fractions of 6 Gy to the cervix, including the macroscopic tumor with an MRI-guided target definition, with an isotropic margin of 5 mm for planning target volume (PTV) definition. Groupe-Europeen de Curietherapie and European society for Radiotherapy and Oncology (GEC-ESTRO) criteria were used for DVH evaluation. Reference comparison plans were optimized for volumetric modulated rapid arc (VMAT) therapy with the RapidArc (RA). Results: The dose to the high-risk volume was calculated with α/β = 10 with 89.6 Gy. For IMPT, the clinical target volume showed a mean dose of 38.2 ± 5.0 Gy (35.0 ±1.8 Gy for RA). The D{sub 98%} was 31.9 ± 2.6 Gy (RA: 30.8 ± 1.0 Gy). With regard to the organs at risk, the 2Gy Equivalent Dose (EQD2) (α/β = 3) to 2 cm{sup 3} of the rectal wall, sigmoid wall, and bladder wall was 62.2 ± 6.4 Gy, 57.8 ± 6.1 Gy, and 80.6 ± 8.7 Gy (for RA: 75.3 ± 6.1 Gy, 66.9 ± 6.9 Gy, and 89.0 ± 7.2 Gy, respectively). For the IMPT boost plans in combination with external beam radiation therapy, all DVH parameters correlated with <5% risk for grades 2 to 4 late gastrointestinal and genitourinary toxicity. Conclusion: In patients who are not eligible for brachytherapy, IMPT as a boost

  17. Phase retrieval based on cosine grating modulation and transport of intensity equation

    Science.gov (United States)

    Chen, Ya-ping; Zhang, Quan-bing; Cheng, Hong; Qian, Yi; Lv, Qian-qian

    2016-10-01

    In order to calculate the lost phase from the intensity information effectively, a new method of phase retrieval which based on cosine grating modulation and transport of intensity equation is proposed. Firstly, the cosine grating is loaded on the spatial light modulator in the horizontal and vertical direction respectively, and the corresponding amplitude of the light field is modulated. Then the phase is calculated by its gradient which is extracted from different direction modulation light illumination. The capability of phase recovery of the proposed method in the presence of noise is tested by simulation experiments. And the results show that the proposed algorithm has a better resilience than the traditional Fourier transform algorithm at low frequency noise. Furthermore, the phase object of different scales can be retrieved using the proposed algorithm effectively by changing the frequency of cosine grating, which can control the imaging motion expediently.

  18. Cancer Immunotherapy: Selected Targets and Small-Molecule Modulators.

    Science.gov (United States)

    Weinmann, Hilmar

    2016-03-04

    There is a significant amount of excitement in the scientific community around cancer immunotherapy, as this approach has renewed hope for many cancer patients owing to some recent successes in the clinic. Currently available immuno-oncology therapeutics under clinical development and on the market are mostly biologics (antibodies, proteins, engineered cells, and oncolytic viruses). However, modulation of the immune system with small molecules offers several advantages that may be complementary and potentially synergistic to the use of large biologicals. Therefore, the discovery and development of novel small-molecule modulators is a rapidly growing research area for medicinal chemists working in cancer immunotherapy. This review provides a brief introduction into recent trends related to selected targets and pathways for cancer immunotherapy and their small-molecule pharmacological modulators.

  19. Surface phase defects induced downstream laser intensity modulation in high-power laser facility

    Institute of Scientific and Technical Information of China (English)

    Xin Zhang; Wei Zhou; Wanjun Dai; Dongxia Hu; Xuewei Deng; Wanqing Huang; Lidan Zhou; Qiang Yuan; Xiaoxia Huang; De’en Wang; Ying Yang

    2016-01-01

    Optics surface phase defects induced intensity modulation in high-power laser facility for inertial confinement fusion research is studied. Calculations and experiments reveal an exact mapping of the modulation patterns and the optics damage spot distributions from the surface phase defects. Origins are discussed during the processes of optics manufacturing and diagnostics, revealing potential improvements for future optics manufacturing techniques and diagnostic index, which is meaningful for fusion level laser facility construction and its operation safety.

  20. A Novel Temperature-Compensated, Intensity-Modulated Fiber Bragg Grating Sensor System

    Institute of Scientific and Technical Information of China (English)

    Xin-Yong Dong; Hwa-Yaw Tam

    2008-01-01

    An intensity-modulated, fiber Bragg grating (FBG) sensor system based on radio-frequency (RF) signal measurement is presented. The RF signal is generated at a photodetector by two modulated optical signals reflected from the sensing FBG and a reference one. Bragg wavelength shift of the sensing FBG changes intensity of the RF signal by changing phase difference between the two optical signals, with temperature effect being compensated automatically by the reference FBG. Strain measurement with a maximum sensitivity of -0.34 μV/με has been achieved.

  1. TU-F-12A-03: Using 18F-FDG-PET-CT and Deformable Registration During Head-And-Neck Cancer (HNC) Intensity Modulated Radiotherapy (IMRT) to Predict Treatment Response

    Energy Technology Data Exchange (ETDEWEB)

    Vergalasova, I; Mowery, Y; Yoo, D; Brizel, D; Das, S [Duke University Medical Center, Durham, NC (United States)

    2014-06-15

    Purpose: To evaluate the effect of deformable vs. rigid registration of pre-treatment 18F-FDG-PET-CT to intra-treatment 18F-FDG-PET-CT on different standardized uptake value (SUV) parameters and investigate which parameters correlate best with post-treatment response in patients undergoing IMRT for HNC. Methods: Pre-treatment and intra-treatment PET-CT (after 20Gy) scans were acquired, in addition to a 12 week post-treatment PET-CT to assess treatment response. Primary and lymph node gross tumor volumes (GTV-PRI and GTV-LN) were contoured on the pre-treatment CT. These contours were then mapped to intra-treatment PET images via rigid and deformable registration. Absolute changes from pre- to intra-treatment scans for rigid and deformable registration were extracted for the following parameters: SUV-MAX, SUV-MEAN, SUV-20%, SUV-40%, and SUV-60% (SUV-X% is the minimum SUV to the highest-intensity X% volume). Results: Thirty-eight patients were evaluated, with 27 available for classification as complete or incomplete response (CR/ICR). The pre-treatment average tumor volumes for the patients were 24.05cm{sup 3} for GTV-PRI and 23.4cm{sup 3} for GTV-LN. For GTV-PRI, there was no statistically significant difference between rigid vs. deformable registration across all ΔSUV parameters. For GTV-LN contours, all parameters were significantly different except for ΔSUV-MAX. For deformably-registered GTV-PRI, changes in the following metrics were significantly different for CR vs. ICR: SUV-MEAN(p=0.003), SUV-20%(p=0.02), SUV-40%(p=0.02), and SUV-60%(p=0.008). The following cutoff values separated CR from ICR with high sensitivity and specificity: ΔSUV-MEAN=1.49, ΔSUV-20%=2.39, ΔSUV-40%=1.80 and ΔSUV-60%=1.31. Corresponding areas under the Receiver Operating Characteristics curve were 0.90, 0.81, 0.81, and 0.85, respectively. Conclusion: Rigidly and deformably registered contours yielded statistically similar SUV parameters for GTV-PRI, but not GTV-LN. This implies that

  2. Bile Acid Malabsorption After Pelvic and Prostate Intensity Modulated Radiation Therapy: An Uncommon but Treatable Condition

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Victoria [Academic Urology Unit, Institute of Cancer Research and The Royal Marsden Hospital, London and Sutton (United Kingdom); Benton, Barbara [Gastroenterology Unit, Institute of Cancer Research and The Royal Marsden Hospital, London and Sutton (United Kingdom); Sohaib, Aslam [Department of Radiology, Institute of Cancer Research and The Royal Marsden Hospital, London and Sutton (United Kingdom); Dearnaley, David [Academic Urology Unit, Institute of Cancer Research and The Royal Marsden Hospital, London and Sutton (United Kingdom); Andreyev, H. Jervoise N., E-mail: j@andreyev.demon.co.uk [Gastroenterology Unit, Institute of Cancer Research and The Royal Marsden Hospital, London and Sutton (United Kingdom)

    2012-12-01

    Purpose: Intensity modulated radiation therapy (IMRT) is a significant therapeutic advance in prostate cancer, allowing increased tumor dose delivery and increased sparing of normal tissues. IMRT planning uses strict dose constraints to nearby organs to limit toxicity. Bile acid malabsorption (BAM) is a treatable disorder of the terminal ileum (TI) that presents with symptoms similar to radiation therapy toxicity. It has not been described in patients receiving RT for prostate cancer in the contemporary era. We describe new-onset BAM in men after IMRT for prostate cancer. Methods and Materials: Diagnosis of new-onset BAM was established after typical symptoms developed, selenium-75 homocholic acid taurine (SeHCAT) scanning showed 7-day retention of <15%, and patients' symptoms unequivocally responded to a bile acid sequestrant. The TI was identified on the original radiation therapy plan, and the radiation dose delivered was calculated and compared with accepted dose-volume constraints. Results: Five of 423 men treated in a prospective series of high-dose prostate and pelvic IMRT were identified with new onset BAM (median age, 65 years old). All reported having normal bowel habits before RT. The volume of TI ranged from 26-141 cc. The radiation dose received by the TI varied between 11.4 Gy and 62.1 Gy (uncorrected). Three of 5 patients had TI treated in excess of 45 Gy (equivalent dose calculated in 2-Gy fractions, using an {alpha}/{beta} ratio of 3) with volumes ranging from 1.6 cc-49.0 cc. One patient had mild BAM (SeHCAT retention, 10%-15%), 2 had moderate BAM (SeHCAT retention, 5%-10%), and 2 had severe BAM (SeHCAT retention, <5%). The 3 patients whose TI received {>=}45 Gy developed moderate to severe BAM, whereas those whose TI received <45 Gy had only mild to moderate BAM. Conclusions: Radiation delivered to the TI during IMRT may cause BAM. Identification of the TI from unenhanced RT planning computed tomography scans is difficult and may impede

  3. Breast cancer in young women: poor survival despite intensive treatment.

    Directory of Open Access Journals (Sweden)

    Hanna Fredholm

    Full Text Available BACKGROUND: Breast cancer is uncommon in young women and correlates with a less favourable prognosis; still it is the most frequent cancer in women under 40, accounting for 30-40% of all incident female cancer. The aim of this study was to study prognosis in young women, quantifying how much stage at diagnosis and management on the one hand, and tumour biology on the other; each contribute to the worse prognosis seen in this age group. METHODOLOGY/PRINCIPAL FINDINGS: In a registry based cohort of women aged 20-69 (n = 22 017 with a primary diagnosis of invasive breast cancer (1992-2005, women aged 20-34 (n = 471, 35-39 (n = 858 and 40-49 (n = 4789 were compared with women aged 50-69 years (n = 15 899. The cumulative 5-year relative survival ratio and the relative excess mortality (RER were calculated. The cumulative 5-year relative survival ratio was lowest in women aged 20-34. The RER was 2.84 for women aged 20-34 and decreased with increasing age (RER 1.76 and 1.17 for women aged 35-39 and 40-49, respectively. The excess risk was, however, present only in disease stages I and II. For women aged 20-34 with stage I disease RER was 4.63, and 6.70 in the subgroup with tumour size 1-10 mm. The absolute difference in stage I between the youngest and the reference groups amounted to nearly 8%, with a 90% 5-year survival in women aged 20-34. In stages IIa and IIb, the relative excess risk was not as dramatic, but the absolute differences approached 15%. The youngest women with small tumours generally received more aggressive treatment than women in older age groups. CONCLUSIONS: After correction for stage, tumour characteristics and treatment, age remained an independent risk factor for breast cancer death in women <35 years of age. The excess risk for young women was only seen in early stages of disease and was most pronounced in women with small tumours. Young women affected by breast cancer have a high risk of dying compared to their middle

  4. Evaluation of a fast method of EPID-based dosimetry for intensity modulated radiation therapy

    OpenAIRE

    Nelms, Benjamin E.; Rasmussen, Karl H.; Tomé, Wolfgang A.

    2010-01-01

    Electronic portal imaging devices (EPIDs) could potentially be useful for Intensity Modulated Radiation Therapy (IMRT) QA. The data density, high resolution, large active area, and efficiency of the MV EPID make it an attractive option. However, EPIDs were designed to be effective imaging devices, but not dosimeters, and as a result they do not measure dose in tissue-equivalent materials.

  5. Limited benefit of inversely optimised intensity modulation in breast conserving radiotherapy with simultaneously integrated boost

    NARCIS (Netherlands)

    van der Laan, Hans Paul; Dolsma, Willemtje; Schilstra, C; Korevaar, Erik W; de Bock, Geertruida H; Maduro, John H; Langendijk, Johannes A

    2010-01-01

    BACKGROUND AND PURPOSE: To examine whether in breast-conserving radiotherapy (RT) with simultaneously integrated boost (SIB), application of inversely planned intensity-modulated radiotherapy (IMRT-SIB) instead of three-dimensional RT (3D-CRT-SIB) has benefits that justify the additional costs, and

  6. Different current intensities of anodal transcranial direct current stimulation do not differentially modulate motor cortex plasticity.

    Science.gov (United States)

    Kidgell, Dawson J; Daly, Robin M; Young, Kayleigh; Lum, Jarrod; Tooley, Gregory; Jaberzadeh, Shapour; Zoghi, Maryam; Pearce, Alan J

    2013-01-01

    Transcranial direct current stimulation (tDCS) is a noninvasive technique that modulates the excitability of neurons within the motor cortex (M1). Although the aftereffects of anodal tDCS on modulating cortical excitability have been described, there is limited data describing the outcomes of different tDCS intensities on intracortical circuits. To further elucidate the mechanisms underlying the aftereffects of M1 excitability following anodal tDCS, we used transcranial magnetic stimulation (TMS) to examine the effect of different intensities on cortical excitability and short-interval intracortical inhibition (SICI). Using a randomized, counterbalanced, crossover design, with a one-week wash-out period, 14 participants (6 females and 8 males, 22-45 years) were exposed to 10 minutes of anodal tDCS at 0.8, 1.0, and 1.2 mA. TMS was used to measure M1 excitability and SICI of the contralateral wrist extensor muscle at baseline, immediately after and 15 and 30 minutes following cessation of anodal tDCS. Cortical excitability increased, whilst SICI was reduced at all time points following anodal tDCS. Interestingly, there were no differences between the three intensities of anodal tDCS on modulating cortical excitability or SICI. These results suggest that the aftereffect of anodal tDCS on facilitating cortical excitability is due to the modulation of synaptic mechanisms associated with long-term potentiation and is not influenced by different tDCS intensities.

  7. Different Current Intensities of Anodal Transcranial Direct Current Stimulation Do Not Differentially Modulate Motor Cortex Plasticity

    Directory of Open Access Journals (Sweden)

    Dawson J. Kidgell

    2013-01-01

    Full Text Available Transcranial direct current stimulation (tDCS is a noninvasive technique that modulates the excitability of neurons within the motor cortex (M1. Although the aftereffects of anodal tDCS on modulating cortical excitability have been described, there is limited data describing the outcomes of different tDCS intensities on intracortical circuits. To further elucidate the mechanisms underlying the aftereffects of M1 excitability following anodal tDCS, we used transcranial magnetic stimulation (TMS to examine the effect of different intensities on cortical excitability and short-interval intracortical inhibition (SICI. Using a randomized, counterbalanced, crossover design, with a one-week wash-out period, 14 participants (6 females and 8 males, 22–45 years were exposed to 10 minutes of anodal tDCS at 0.8, 1.0, and 1.2 mA. TMS was used to measure M1 excitability and SICI of the contralateral wrist extensor muscle at baseline, immediately after and 15 and 30 minutes following cessation of anodal tDCS. Cortical excitability increased, whilst SICI was reduced at all time points following anodal tDCS. Interestingly, there were no differences between the three intensities of anodal tDCS on modulating cortical excitability or SICI. These results suggest that the aftereffect of anodal tDCS on facilitating cortical excitability is due to the modulation of synaptic mechanisms associated with long-term potentiation and is not influenced by different tDCS intensities.

  8. Advances in three-dimensional conformal radiation therapy physics with intensity modulation.

    Science.gov (United States)

    Webb, S

    2000-09-01

    Intensity-modulated radiation therapy, a specific form of conformal radiation therapy, is currently attracting a lot of attention, and there are high expectations for this class of treatment techniques. Several new technologies are in development, but physicists are still working to improve the physical basis of radiation therapy.

  9. Optimizing Planning and Delivery of High-Precision Robotic Radiotherapy and Intensity-Modulated Proton Therapy

    NARCIS (Netherlands)

    S. van de Water (Steven)

    2015-01-01

    markdownabstract__Abstract__ High-precision robotic radiotherapy and intensity-modulated proton therapy (IMPT) are two relatively new radiotherapy techniques that particularly aim at a highly localized delivery of a curative dose to the tumor, while achieving excellent sparing of the surrounding he

  10. Randomization techniques for the intensity modulation-based quantum stream cipher and progress of experiment

    Science.gov (United States)

    Kato, Kentaro; Hirota, Osamu

    2011-08-01

    The quantum noise based direct encryption protocol Y-OO is expected to provide physical complexity based security, which is thought to be comparable to information theoretic security in mathematical cryptography, for the. physical layer of fiber-optic communication systems. So far, several randomization techniques for the quantum stream cipher by Y-OO protocol have been proposed, but most of them were developed under the assumption that phase shift keying is used as the modulation format. On the other hand, the recent progress in the experimental study on the intensity modulation based quantum stream cipher by Y-OO protocol raises expectations for its realization. The purpose of this paper is to present design and implementation methods of a composite model of the intensity modulation based quantum stream cipher with some randomization techniques. As a result this paper gives a viewpoint of how the Y-OO cryptosystem is miniaturized.

  11. Accommodating practical constraints for intensity-modulated radiation therapy by means of compensators

    CERN Document Server

    Meyer, J

    2001-01-01

    intensity distribution, inverse modelling of the radiation attenuation within the compensator is required. Two novel and independent approaches, based on deconvolution and system identification, respectively, are proposed to accomplish this. To compare the approach with the 'rival' state of the art beam modulation technique, theoretical and experimental examination of the modulated fields generated by manufactured compensators and multileaf collimators is presented. This comparison focused on the achievable resolution of the intensity modulated beams in lateral and longitudinal directions. To take into account the characteristics of a clinical environment, a comprehensive study has been carried out to investigate the suitability of the most common commercially available treatment couch systems for their suitability for IMRT treatments. In this context, an original rule based advisory system has been developed to alert the operator of any potential collision of the beam with the moveable supporting structures ...

  12. Duplicating a tandem and ovoids distribution with intensity-modulated radiotherapy: a feasibility study.

    Science.gov (United States)

    Malhotra, Harish K; Avadhani, Jaiteerth S; deBoer, Steven F; Jaggernauth, Wainwright; Kuettel, Michael R; Podgorsak, Matthew B

    2007-07-17

    Brachytherapy plays an important role in the definitive treatment of cervical cancers by radiotherapy. In the present study, we investigated whether sliding-window intensity-modulated radiation therapy (IMRT) can achieve a pear-shaped distribution with a similar sharp dose falloff identical to that of brachytherapy. The computed tomography scans of a tandem and ovoid patient were pushed to both a high dose rate (HDR) and an IMRT treatment planning system (TPS) after the rectum, bladder, and left and right femoral heads had been outlined, ensuring identical structures in both planning systems. A conventional plan (7 Gy in 5 fractions, defined as the average dose to the left and right point A) was generated for HDR treatment. The 150%, 125%, 100%, 75%, 50%, and 25% isodose curves were drawn on each slice and then transferred to the IMRT TPS. The 100% isodose envelope from the HDR plan was the target for IMRT planning. A 7-field IMRT plan using 6-MV X-ray beams was generated and compared with the HDR plan using isodose conformity to the target and 125% volume, dose-volume histograms, and integral dose. The resulting isodose distribution demonstrated good agreement between the HDR and IMRT plans in the 100% and 125% isodose range. The dose falloff in the HDR plan was much steeper than that in the IMRT plan, but it also had a substantially higher maximum dose. Integral dose for the target, rectum, and bladder were found to be 6.69 J, 1.07 J, and 1.02 J in the HDR plan; the respective values for IMRT were 3.47 J, 1.79 J, and 1.34 J. Our preliminary results indicate that the HDR dose distribution can be replicated using a standard sliding-window IMRT dose delivery technique for points lying closer to the three-dimensional isodose envelope surrounding point A. Differences in radiobiology and patient positioning between the two techniques merit further consideration.

  13. Automation and Intensity Modulated Radiation Therapy for Individualized High-Quality Tangent Breast Treatment Plans

    Energy Technology Data Exchange (ETDEWEB)

    Purdie, Thomas G., E-mail: Tom.Purdie@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Techna Institute, University Health Network, Toronto, Ontario (Canada); Dinniwell, Robert E.; Fyles, Anthony [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Sharpe, Michael B. [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Techna Institute, University Health Network, Toronto, Ontario (Canada)

    2014-11-01

    Purpose: To demonstrate the large-scale clinical implementation and performance of an automated treatment planning methodology for tangential breast intensity modulated radiation therapy (IMRT). Methods and Materials: Automated planning was used to prospectively plan tangential breast IMRT treatment for 1661 patients between June 2009 and November 2012. The automated planning method emulates the manual steps performed by the user during treatment planning, including anatomical segmentation, beam placement, optimization, dose calculation, and plan documentation. The user specifies clinical requirements of the plan to be generated through a user interface embedded in the planning system. The automated method uses heuristic algorithms to define and simplify the technical aspects of the treatment planning process. Results: Automated planning was used in 1661 of 1708 patients receiving tangential breast IMRT during the time interval studied. Therefore, automated planning was applicable in greater than 97% of cases. The time for treatment planning using the automated process is routinely 5 to 6 minutes on standard commercially available planning hardware. We have shown a consistent reduction in plan rejections from plan reviews through the standard quality control process or weekly quality review multidisciplinary breast rounds as we have automated the planning process for tangential breast IMRT. Clinical plan acceptance increased from 97.3% using our previous semiautomated inverse method to 98.9% using the fully automated method. Conclusions: Automation has become the routine standard method for treatment planning of tangential breast IMRT at our institution and is clinically feasible on a large scale. The method has wide clinical applicability and can add tremendous efficiency, standardization, and quality to the current treatment planning process. The use of automated methods can allow centers to more rapidly adopt IMRT and enhance access to the documented

  14. Intensity of follow-up after pancreatic cancer resection.

    Science.gov (United States)

    Castellanos, Jason A; Merchant, Nipun B

    2014-03-01

    The prognosis of patients diagnosed with pancreatic adenocarcinoma remains dismal. Of the 15-20 % of patients who are candidates for potentially curative resection, 66-92 % will develop recurrent disease. Although guidelines for surveillance in the postoperative setting exist, they are not evidence based, and there is wide variability of strategies utilized. Current surveillance guidelines as suggested by the National Comprehensive Cancer Network (NCCN) include routine history and physical, measurement of serum cancer-associated antigen 19-9 (CA19-9) levels, and computed tomographic imaging at 3- to 6-month intervals for the first 2 years, and annually thereafter. However, the lack of prospective clinical data examining the efficacy of different surveillance strategies has led to a variability of the intensity of follow-up and a lack of consensus on its necessity and efficacy. Recent therapeutic advances may have the potential to significantly alter survival after recurrence, but a careful consideration of current surveillance strategies should be undertaken to optimize existing approaches in the face of high recurrence and low survival rates.

  15. HIGH-INTENSITY FOCUSED ULTRASOUND CASTRATION FOR BREAST CANCER PATIENTS

    Institute of Scientific and Technical Information of China (English)

    王书文; 和新盈; 石景森; 赵东利; 李明众; 王诚; 薛文华

    2003-01-01

    Objective: To evaluate the safety and efficacy of external high-intensity focused ultrasound(HIFU) castration for breast cancerous patients after mastectomy if they are at a high risk of recurrence. Methods: We recruited 52 consecutive patients with primary operable breast cancer who were treated with mastectomy with excision of regional lymph nodes. Patients were positive for ER and PR immuno- cytochemical staining, node-positive, un-menopause, over 40 years old and were divided into two groups randomly. For castration, 26 patients received one or two times of HIFU treatment within five days, and the other patients received radiotherapy with DT 18Gy/9 f/11days. During and after the treatment, local changes and systemic response of the patients were observed. Results: After 1 month treatment, levels of serum E1 and E2 were significantly decreased compared to before treatment in HIFU groups (P<0.01 and P<0.001). The same changes were occurred in radiotherapy(RT) groups (P<0.05 and P<0.01). The levels of serum E1 or E2 in RT groups were higher than in HIFU groups (P<0.05). The symptom distribution of 'climacteric syndrome' of HIFU groups were significantly different from RT groups (P<0.01). The follow-up time was 4 months. The incidence of amenorrhea was 100% in all patients. No serious complications were seen. The temperature, pulse, blood pressure, and respiratory rate of the patients were almost normal. Conclusion: We have shown that the use of HIFU in the castrating of patients with breast cancer is feasible, safe and effective. This technology may provide a rapid noninvasive alterative to conventional bilateral oophorectomy or RT castration.

  16. Observation of curative effect of intensity modulated radiation therapy combined with concurrent chemotherapy in the treatment of locally terminal nasopharynx cancer%调强放疗联合同期化疗治疗局部晚期鼻咽癌的疗效观察

    Institute of Scientific and Technical Information of China (English)

    黄瑞文; 冯庆; 柯柳杨; 李能平; 梁文胜

    2015-01-01

    Objective To explore the curative effect of intensity modulated radiation therapy (IMRT).Methods Patients with locally terminal nasopharynx cancer who were admitted to our hospital from February 2011 to February 2014 were divided to A group (experimental group, 46 patients) and B group (control group, 40 patients). A group was treated with IMRT and DN (Docetaxel and Nedaplatin) combined with concurrent chemotherapy, and the B group was treated with conventional chemotherapy and DN combined with concurrent chemotherapy. The curative effect, early adverse reactions, advanced adverse reactions of two groups were collected, and the data was analyzed with Chi-square test.ResultsThe difference in curative effect of two groups was not great (P>0.05). In the aspect of early adverse reactions, the mobility of oral mucositis of two groups was 100%. The mobility of Ⅲ level oral mucositis, anemia and leukopenia of A group was significantly lower than that of B group (P0.05).在早期不良反应中,口腔黏膜炎在两组的发病率均为100%,Ⅲ度口腔黏膜炎、贫血和白细胞减少的发病率在A组中明显比B组少(P<0.05);在晚期不良反应中,口干反应、张口困难、黏膜损伤的发病率在A组中明显低于B组(P<0.05). 结论 IMRT联合同期化疗治疗局部晚期鼻咽癌可以减少早期不良反应和晚期不良反应的发病率.

  17. Defining the “Hostile Pelvis” for Intensity Modulated Radiation Therapy: The Impact of Anatomic Variations in Pelvic Dimensions on Dose Delivered to Target Volumes and Organs at Risk in Patients With High-Risk Prostate Cancer Treated With Whole Pelvic Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yirmibeşoğlu Erkal, Eda, E-mail: eyirmibesoglu@yahoo.com [Department of Radiation Oncology, Kocaeli University Faculty of Medicine, Kocaeli (Turkey); Karabey, Sinan [Department of Radiation Oncology, Kocaeli University Faculty of Medicine, Kocaeli (Turkey); Karabey, Ayşegül [Department of Radiation Oncology, Kocaeli State Hospital, Kocaeli (Turkey); Hayran, Mutlu [Department of Preventive Oncology, Hacettepe University Cancer Institute, Ankara (Turkey); Erkal, Haldun Şükrü [Department of Radiation Oncology, Sakarya University Faculty of Medicine, Sakarya (Turkey)

    2015-07-15

    Purpose: The aim of this study was to evaluate the impact of variations in pelvic dimensions on the dose delivered to the target volumes and the organs at risk (OARs) in patients with high-risk prostate cancer (PCa) to be treated with whole pelvic radiation therapy (WPRT) in an attempt to define the hostile pelvis in terms of intensity modulated radiation therapy (IMRT). Methods and Materials: In 45 men with high-risk PCa to be treated with WPRT, the target volumes and the OARs were delineated, the dose constraints for the OARs were defined, and treatment plans were generated according to the Radiation Therapy Oncology Group 0924 protocol. Six dimensions to reflect the depth, width, and height of the bony pelvis were measured, and 2 indexes were calculated from the planning computed tomographic scans. The minimum dose (D{sub min}), maximum dose (D{sub max}), and mean dose (D{sub mean}) for the target volumes and OARs and the partial volumes of each of these structures receiving a specified dose (V{sub D}) were calculated from the dose-volume histograms (DVHs). The data from the DVHs were correlated with the pelvic dimensions and indexes. Results: According to an overall hostility score (OHS) calculation, 25 patients were grouped as having a hospitable pelvis and 20 as having a hostile pelvis. Regarding the OHS grouping, the DVHs for the bladder, bowel bag, left femoral head, and right femoral head differed in favor of the hospitable pelvis group, and the DVHs for the rectum differed for a range of lower doses in favor of the hospitable pelvis group. Conclusions: Pelvimetry might be used as a guide to define the challenging anatomy or the hostile pelvis in terms of treatment planning for IMRT in patients with high-risk PCa to be treated with WPRT.

  18. Treatment planning, optimization, and beam delivery technqiues for intensity modulated proton therapy

    Science.gov (United States)

    Sengbusch, Evan R.

    , beamlet weight, the number of delivered beamlets, and the number of delivery angles. These methods are evaluated via treatment planning studies including left-sided whole breast irradiation, lung stereotactic body radiotherapy, nasopharyngeal carcinoma, and whole brain radiotherapy with hippocampal avoidance. Improvements in efficiency and efficacy relative to traditional proton therapy and intensity modulated photon radiation therapy are discussed.

  19. SU-F-BRD-06: Robust Dose Calculation in Intensity Modulated Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Brosch, R [ASU, Tempe, AZ (United States); Liu, W [Mayo Clinic Arizona, Phoenix, AZ (United States)

    2015-06-15

    Purpose: Commissioning data for intensity modulated proton therapy (IMPT) must be post-processed by fits to ad-hoc functions to derive the dose calculation kernel parameters in a treatment planning system (TPS). Whether from experimental measurement or Monte Carlo simulation, the limited and noisy nature of such data makes this task very challenging. We present a method to improve the modeling of the lateral dose distribution of clinical energy proton beams in water to commission an in-house IMPT dose calculation engine. Methods: A linear sum of three Gaussian distribution functions was fitted to the lateral dose data in logarithmic scale. Starting values of fitting solutions were determined from the Generalized Highland Approximation. We exhaustively optimized the combinations of data weights with upper bounds of the fitting solutions to minimize confidence intervals of the fitting solutions while maintaining the coefficient of determination (R{sup 2}). Results: Across all energies, average confidence bounds improved 72.88% [Max: 88.28%, Min: 55.05%] for small angle coulomb scattering, 114.25% [409.13%, 66.72%,] for nuclear scattering, and 68.66% [141.09%, 33.27%] for large angle coulomb scattering, while the coefficients of determination of the fits (R{sup 2}) remained comparable. On average R {sup 2} only changed 0.18% and were very close to 1 (approx. 0.999). Wilcoxon signed rank tests comparing unweighted/unbounded fits with weighted/bounded fits averaged 0.0146 (Max: 0.177, Min: 7.05×10−{sup 7}) for small angle Coulomb, 0.0903 (0.945, 7.05×10−{sup 7}) for nuclear, and 0.254 (0.871, 1.86×10−{sup 6}) for large angle Coulomb scattering. This allows rejection of the null hypothesis for small angle Coulomb scattering at the 0.015 level and nuclear interaction at the 0.1 level. Conclusion: Optimal weights assigned to IMPT lateral dose data minimized fitting to stochastic noise in the tail region. Optimizing the upper bounds of fitting parameters improved

  20. Pancreatic cancer planning: Complex conformal vs modulated therapies.

    Science.gov (United States)

    Chapman, Katherine L; Witek, Matthew E; Chen, Hongyu; Showalter, Timothy N; Bar-Ad, Voichita; Harrison, Amy S

    2016-01-01

    To compare the roles of intensity-modulated radiation therapy (IMRT) and volumetric- modulated arc therapy (VMAT) therapy as compared to simple and complex 3-dimensional chemoradiotherpy (3DCRT) planning for resectable and borderline resectable pancreatic cancer. In all, 12 patients who received postoperative radiotherapy (8) or neoadjuvant concurrent chemoradiotherapy (4) were evaluated retrospectively. Radiotherapy planning was performed for 4 treatment techniques: simple 4-field box, complex 5-field 3DCRT, 5 to 6-field IMRT, and single-arc VMAT. All volumes were approved by a single observer in accordance with Radiation Therapy Oncology Group (RTOG) Pancreas Contouring Atlas. Plans included tumor/tumor bed and regional lymph nodes to 45Gy; with tumor/tumor bed boosted to 50.4Gy, at least 95% of planning target volume (PTV) received the prescription dose. Dose-volume histograms (DVH) for multiple end points, treatment planning, and delivery time were assessed. Complex 3DCRT, IMRT, and VMAT plans significantly (p plans that are most commonly reported in the literature. IMRT plans resulted in decreased mean liver dose, liver (V35), and left kidney (V15, V18, V20). VMAT plans decreased small bowel (D10%, D15%), small bowel (V35, V45), stomach (D10%, D15%), stomach (V35, V45), mean liver dose, liver (V35), left kidney (V15, V18, V20), and right kidney (V18, V20). VMAT plans significantly decreased small bowel (D10%, D15%), left kidney (V20), and stomach (V45) as compared with IMRT plans. Treatment planning and delivery times were most efficient for simple 4-field box and VMAT. Excluding patient setup and imaging, average treatment delivery was within 10minutes for simple and complex 3DCRT, IMRT, and VMAT treatments. This article shows significant improvements in 3D plan performance with complex planning over the more frequently compared 3- or 4-field simple 3D planning techniques. VMAT plans continue to demonstrate potential for the most organ sparing. However

  1. High-speed operation of optical exclusive OR circuit based on balanced detection and intensity modulation

    Directory of Open Access Journals (Sweden)

    Koichi Takiguchi

    2015-12-01

    Full Text Available We report the evaluated results of an optical exclusive OR (XOR circuit for high-speed binary signals, which operates based on balanced detection and intensity modulation. This circuit partly adopts simple electronics in order to achieve simple configuration and operation. Two input optical binary signals into a balanced photo detector produce an electrical signal for directly driving a modulator. The modulator modulates the lightwave from a laser diode and generates optical XOR output of the two input optical signals. After briefly explaining its configuration and operating principle, We demonstrate some experimental results to show its potential. We show its successful operation at 40 Gbit/s binary signals including bit error rate measurement.

  2. Immune Modulation by Chemotherapy or Immunotherapy to Enhance Cancer Vaccines

    Directory of Open Access Journals (Sweden)

    Marc Mansour

    2011-08-01

    Full Text Available Chemotherapy has been a mainstay in cancer treatment for many years. Despite some success, the cure rate with chemotherapy remains unsatisfactory in some types of cancers, and severe side effects from these treatments are a concern. Recently, understanding of the dynamic interplay between the tumor and immune system has led to the development of novel immunotherapies, including cancer vaccines. Cancer vaccines have many advantageous features, but their use has been hampered by poor immunogenicity. Many developments have increased their potency in pre-clinical models, but cancer vaccines continue to have a poor clinical track record. In part, this could be due to an inability to effectively overcome tumor-induced immune suppression. It had been generally assumed that immune-stimulatory cancer vaccines could not be used in combination with immunosuppressive chemotherapies, but recent evidence has challenged this dogma. Chemotherapies could be used to condition the immune system and tumor to create an environment where cancer vaccines have a better chance of success. Other types of immunotherapies could also be used to modulate the immune system. This review will discuss how immune modulation by chemotherapy or immunotherapy could be used to bolster the effects of cancer vaccines and discuss the advantages and disadvantages of these treatments.

  3. Immune Modulation by Chemotherapy or Immunotherapy to Enhance Cancer Vaccines

    Energy Technology Data Exchange (ETDEWEB)

    Weir, Genevieve M. [Suite 411, 1344 Summer St., Immunovaccine Inc., Halifax, NS, B3H 0A8 (Canada); Room 11-L1, Sir Charles Tupper Building, Department of Microbiology & Immunology, Dalhousie University, 5850 College St, Halifax, NS, B3H 1X5 (Canada); Liwski, Robert S. [Room 11-L1, Sir Charles Tupper Building, Department of Microbiology & Immunology, Dalhousie University, 5850 College St, Halifax, NS, B3H 1X5 (Canada); Room 206E, Dr. D. J. Mackenzie Building, Department of Pathology, Dalhousie University, 5788 University Avenue, Halifax, NS, B3H 2Y9 (Canada); Mansour, Marc [Suite 411, 1344 Summer St., Immunovaccine Inc., Halifax, NS, B3H 0A8 (Canada)

    2011-08-05

    Chemotherapy has been a mainstay in cancer treatment for many years. Despite some success, the cure rate with chemotherapy remains unsatisfactory in some types of cancers, and severe side effects from these treatments are a concern. Recently, understanding of the dynamic interplay between the tumor and immune system has led to the development of novel immunotherapies, including cancer vaccines. Cancer vaccines have many advantageous features, but their use has been hampered by poor immunogenicity. Many developments have increased their potency in pre-clinical models, but cancer vaccines continue to have a poor clinical track record. In part, this could be due to an inability to effectively overcome tumor-induced immune suppression. It had been generally assumed that immune-stimulatory cancer vaccines could not be used in combination with immunosuppressive chemotherapies, but recent evidence has challenged this dogma. Chemotherapies could be used to condition the immune system and tumor to create an environment where cancer vaccines have a better chance of success. Other types of immunotherapies could also be used to modulate the immune system. This review will discuss how immune modulation by chemotherapy or immunotherapy could be used to bolster the effects of cancer vaccines and discuss the advantages and disadvantages of these treatments.

  4. Can Intensity-Modulated Radiotherapy Preserve Oral Health-Related Quality of Life of Nasopharyngeal Carcinoma Patients?

    Energy Technology Data Exchange (ETDEWEB)

    Pow, Edmond H.N., E-mail: ehnpow@hku.hk [Oral Rehabilitation, University of Hong Kong Faculty of Dentistry, Hong Kong Special Administrative Region (China); Kwong, Dora L.W.; Sham, Jonathan S.T.; Lee, Victor H.F.; Ng, Sherry C.Y. [Department of Clinical Oncology, University of Hong Kong Li Ka Shing Faculty of Medicine, Hong Kong Special Administrative Region (Hong Kong)

    2012-06-01

    Purpose: To investigate the changes in salivary function and oral health-related quality of life for patients with nasopharyngeal carcinoma treated by intensity-modulated radiotherapy (IMRT). Methods and Materials: A total of 57 patients with early-stage nasopharyngeal carcinoma received IMRT. The parotid and whole saliva flow was measured, and the Medical Outcomes Study 36-item short form, European Organization for Research and Treatment of Cancer Quality of Life questionnaire-C30, European Organization for Research and Treatment of Cancer Quality of Life questionnaire 35-item head-and-neck module, and Oral Health Impact Profile questionnaires were completed at baseline and 2, 6, 12, 18, and 24 months after IMRT. Results: Parotid saliva flow recovered fully after 1 year and maintained. Whole saliva flow recovered partially to 40% of baseline. A general trend of deterioration in most quality of life scales was observed after IMRT, followed by gradual recovery. Persistent oral-related symptoms were found 2 years after treatment. Conclusion: IMRT for early-stage nasopharyngeal carcinoma could only partially preserve the whole salivary function and oral health-related quality of life.

  5. Parameter study for polymer solar modules based on various cell lengths and light intensities

    Energy Technology Data Exchange (ETDEWEB)

    Slooff, L.H.; Burgers, A.R.; Bende, E.E.; Kroon, J.M. [ECN Solar Energy, P.O. Box 1, 1755 ZG Petten (Netherlands); Veenstra, S.C. [ECN Solar Energy, Solliance, High Tech Campus 5, P63, 5656AE Eindhoven (Netherlands)

    2013-10-15

    Polymer solar cells may be applied in portable electronic devices, where light intensity and spectral distribution of the illuminating source can be very different compared to outdoor applications. As the power output of solar cells depends on temperature, light intensity and spectrum, the design of the module must be optimized for the specific illumination conditions in the different applications. The interconnection area between cells in a module must be as narrow as possible to maximize the active area, also called geometrical fill factor, of the module. Laser scribing has the potential to realize this. The optimal width of the interconnection zone depends both on technological limitations, e.g. laser scribe width and the minimal distance between scribes, and electrical limitations like resistive losses. The latter depends on the generated current in the cell and thus also on illumination intensity. Besides that, also the type of junction, i.e. a single or tandem junction, will influence the optimal geometry. In this paper a calculation model is presented that can be used for electrical modeling of polymer cells and modules in order to optimize the performance for the specific illumination conditions.

  6. A Two-Dimensional Signal Space for Intensity-Modulated Channels

    CERN Document Server

    Karout, Johnny; Kschischang, Frank R; Agrell, Erik

    2012-01-01

    A two-dimensional signal space for intensity- modulated channels is presented. Modulation formats using this signal space are designed to maximize the minimum distance between signal points while satisfying average and peak power constraints. The uncoded, high-signal-to-noise ratio, power and spectral efficiencies are compared to those of the best known formats. The new formats are simpler than existing subcarrier formats, and are superior if the bandwidth is measured as 90% in-band power. Existing subcarrier formats are better if the bandwidth is measured as 99% in-band power.

  7. Two-tone intensity-modulated optical stimulus for self-referencing microwave characterization of high-speed photodetectors

    Science.gov (United States)

    Wang, Heng; Zhang, Shangjian; Zou, Xinhai; Zhang, Yali; Lu, Rongguo; Zhang, Zhiyao; Zhang, Xiaoxia; Liu, Yong

    2016-08-01

    The two-tone intensity modulated optical stimulus is proposed and demonstrated for measuring the high-frequency response of photodetectors. The method provides a narrow linewidth and wide bandwidth optical stimulus based on the two-tone modulation of a Mach-Zehnder electro-optical intensity modulator, and achieves the self-referenced measurement of photodetectors without the need for correcting the power variation of optical stimulus. Moreover, the two-tone intensity modulation method allows bias-independent measurement with doubled measuring frequency range. In the experiment, the consistency between our method and the conventional methods verifies the simple but accurate measurement.

  8. Quality of Intensity Modulated Radiation Therapy Treatment Plans Using a (60)Co Magnetic Resonance Image Guidance Radiation Therapy System

    DEFF Research Database (Denmark)

    Wooten, H Omar; Green, Olga; Yang, Min

    2015-01-01

    PURPOSE: This work describes a commercial treatment planning system, its technical features, and its capabilities for creating (60)Co intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. METHODS AND MATERIALS......: The ViewRay treatment planning system (Oakwood Village, OH) was used to create (60)Co IMRT treatment plans for 33 cancer patients with disease in the abdominal, pelvic, thorax, and head and neck regions using physician-specified patient-specific target coverage and organ at risk (OAR) objectives. Backup......% prescription reference isodoses, respectively, and heterogeneity was on average 4% greater. Comparisons of OAR mean dose showed generally better sparing with linac plans in the low-dose range organs with mean doses >20 Gy. The mean doses for all (60)Co plan OARs were within...

  9. The impact of leaf width and plan complexity on DMLC tracking of prostate intensity modulated arc therapy

    DEFF Research Database (Denmark)

    Pommer, Tobias; Falk, Marianne; Poulsen, Per Rugaard;

    2013-01-01

    Purpose: Intensity modulated arc therapy (IMAT) is commonly used to treat prostate cancer. The purpose of this study was to evaluate the impact of leaf width and plan complexity on dynamic multileaf collimator (DMLC) tracking for prostate motion management during IMAT treatments.Methods: Prostate...... position constraints during plan optimization. A subset of the M-MLC plans was converted for delivery with the HDMLC, isolating the effect of the different leaf widths. The gamma index was used for evaluation. Tracking errors caused by target localization, leaf fitting, and leaf adjustment were analyzed.......Results: The gamma pass rate was significantly improved with DMLC tracking compared to no tracking (p gamma index pass rate was 98.6% (range 94.8%-100%) with the HDMLC and 98.1% (range 95.4%-99.7%) with the M-MLC, using 3%, 3 mm criteria and the planned dose as reference...

  10. A model-aided segmentation in urethra identification based on an atlas human autopsy image for intensity modulated radiation therapy.

    Science.gov (United States)

    Song, Yan; Muller, Boris; Burman, Chandra; Mychalczak, Borys; Song, Yulin

    2007-01-01

    In order to protect urethra in radiation therapy of prostate cancer, the urethra must be identified and localized as an organ at risk (OAR) for the inverse treatment planning in intensity modulated radiation therapy (IMRT). Because the prostatic urethra and its surrounding prostate tissue have similar physical characteristics, such as linear attenuation coefficient and density, it is difficult to distinct the OAR from the target in CT images. To localize the urethra without using contrast agent or additional imaging modalities other than planning CT images, a different approach was developed using a standard atlas of human anatomy image. This paper reports an investigation, in which an adult urethra was modeled based on a human anatomic image. An elastic model was build to account for a uniform tissue deformation of the prostate. This model was then applied to patients to localize their urethras and preliminary results are presented.

  11. Impact of High-intensity Intermittent and Moderate-intensity Continuous Exercise on Autonomic Modulation in Young Men.

    Science.gov (United States)

    Cabral-Santos, C; Giacon, T R; Campos, E Z; Gerosa-Neto, J; Rodrigues, B; Vanderlei, L C M; Lira, F S

    2016-06-01

    The aim of this study was to compare heart rate variability (HRV) recovery after two iso-volume (5 km) exercises performed at different intensities. 14 subjects volunteered (25.17±5.08 years; 74.7±6.28 kg; 175±0.05 cm; 59.56±5.15 mL·kg(-1)·min(-1)) and after determination of peak oxygen uptake (VO2Peak) and the speed associated with VO2Peak (sVO2Peak), the subjects completed 2 random experimental trials: high-intensity exercise (HIE - 1:1 at 100% sVO2Peak), and moderate-intensity continuous exercise (MIE - 70% sVO2Peak). HRV and RR intervals were monitored before, during and after the exercise sessions together with, the HRV analysis in the frequency domains (high-frequency - HF: 0.15 to 0.4 Hz and low-frequency - LF: 0.04 to 0.15 Hz components) and the ratio between them (LF/HF). Statistical analysis comparisons between moments and between HIE and MIE were performed using a mixed model. Both exercise sessions modified LFlog, HFlog, and LF/HF (F=16.54, F=19.32 and F=5.17, p<0.05, respectively). A group effect was also found for LFlog (F=23.91, p<0.05), and HFlog (F=57.55, p< 0.05). LF/HF returned to resting value 15 min after MIE exercise and 20 min after HIE exercise. This means that the heavy domain (aerobic and anaerobic threshold) induces dissimilar autonomic modification in physically active subjects. Both HIE and MIE modify HRV, and generally HIE delays parasympathetic autonomic modulation recovery after iso-volume exercise.

  12. MIMO Free-Space Optical Communication Employing Subcarrier Intensity Modulation in Atmospheric Turbulence Channels

    Science.gov (United States)

    Ghassemlooy, Zabih; Popoola, Wasiu O.; Ahmadi, Vahid; Leitgeb, Erich

    In this paper, we analyse the error performance of transmitter/receiver array free-space optical (FSO) communication system employing binary phase shift keying (BPSK) subcarrier intensity modulation (SIM) in clear but turbulent atmospheric channel. Subcarrier modulation is employed to eliminate the need for adaptive threshold detector. Direct detection is employed at the receiver and each subcarrier is subsequently demodulated coherently. The effect of irradiance fading is mitigated with an array of lasers and photodetectors. The received signals are linearly combined using the optimal maximum ratio combining (MRC), the equal gain combining (EGC) and the selection combining (SelC). The bit error rate (BER) equations are derived considering additive white Gaussian noise and log normal intensity fluctuations. This work is part of the EU COST actions and EU projects.

  13. Optical Intensity Modulation in an LiNbO3 Slab-Coupled Waveguide

    Directory of Open Access Journals (Sweden)

    Yalin Lu

    2008-01-01

    Full Text Available Optical intensity modulation has been demonstrated through switching the optical beam between the main core waveguide and a closely attached leaky slab waveguide by applying a low-voltage electrical field. Theory for simulating such an LiNbO3 slab-coupled waveguide structure was suggested, and the result indicates the possibility of making the spatial guiding mode large, circular and symmetric, which further allows the potential to significantly reduce the coupling losses with adjacent lasers and optical networks. Optical intensity modulation using electro-optic effect was experimentally demonstrated in a 5 cm long waveguide fabricated by using a procedure of soft proton exchange and then an overgrowth of thin LN film on top of a c-cut LiNbO3 wafer.

  14. Wideband Analog Transmission System Based on the External Intensity Electro-Optic Modulator

    Directory of Open Access Journals (Sweden)

    Jiri Svarny

    2016-01-01

    Full Text Available The work deals with design and integration of an analog electro-optic transmission system suitable for some specialized tasks of diagnostics and measurements. The system is based on principle of external intensity modulation of fiber guided laser radiation. Besides wideband and almost lossless transmission the system tolerates extreme length of the transmitting medium and ensures ultimate galvanic barrier between the input and output.

  15. Study on the Optimization Algorithms for Intensity-Modulated Radiation Therapy

    Institute of Scientific and Technical Information of China (English)

    LI Yong-jie

    2005-01-01

    @@ Radiotherapy, together with the surgery and chemotherapy, are the three main means for tumor treatment. It is a historic advancement for tumor treatment that the classical three-dimensional (3D)conformal radiotherapy (3DCRT) evolved into the intensity-modulated radiotherapy (IMRT). Whereas,the advantages of IMRT have not yet been fully utilized, because of the complicated clinical conditions.The IMRT planning, one of the key issues of IMRT application, still has many problems open to be further studied.

  16. Simplified polarization demultiplexing based on Stokes vector analysis for intensity-modulation direct-detection systems

    Science.gov (United States)

    Zhou, Xinyu; Yan, Lianshan; Chen, Zhiyu; Yi, Anlin; Pan, Yan; Jiang, Lin; Pan, Wei; Luo, Bin

    2016-10-01

    A simple and effective polarization demultiplexing method is proposed based on the improved Stokes vector analysis and digital signal processor algorithm for the intensity-modulation direct-detection optical communication systems. Such a scheme could significantly simplify optical receivers with low system cost. The experimental results demonstrate the feasibility of our proposed method and show that only 1- and 1.7-dB power penalties are measured for 10- and 25-km transmissions compared to back-to-back case.

  17. 局部晚期非小细胞肺癌适形调强放疗联合多西他赛同步化疗的临床观察%Intensity modulated radiation therapy combined with docetaxl chemotherapy for locally late stage non-small cell lung cancer

    Institute of Scientific and Technical Information of China (English)

    邢晓波; 张美莲; 王宗站; 周宓; 杨金霞

    2011-01-01

    OBJECTIVE: To evaluate the effect of intensity modulated radiation therapy (IMRT) combined with Docetaxl chemotherapy for locally late stage non-small cell lung cancer. METHODS: Totally 65 NSCLC patients were involved. Group A consisted of 35 patients, treated with IMRT combined Docetaxel and Cisplatin chemotherapy, and after radiation therapy, they received Docetaxel and Cisplatin chemotherapy for two therapy cycles. Group B consisted of 30 patients, receiving IMRT, then Docetaxel and Cisplatin chemotherapy for 4- 6 therapy cycle. RESULTS: The overall response rate (CR+PR)was 82. 9% in Group A,and 60. 0% in Group B. The overall response rate of Group A was higher than Group A (P = 0. 04); The one-year and two-year survival rate of Group A were 77. 1% and 48. 6%, and that of Group B were 73. 3% and 43. 3% respectively. There were no significant differences between Group A and Group B in one-year and two-year survival rate (P=0. 63). The incidence of leucopenia was 77. 1% in Group A, and 53.3% in Group B (P = 0. 123); The incidence of radiation-induced esophagitis was 65.7% in Group A, and 53. 3% in Group B (P = 0.582). The incidence of radiation-induced pulmonitis was 45. 7% in Group A, and 40. 0% in Group B (P = 0. 898). CONCLUSION: The short-term effect of intensity modulated radiation therapy (IMRT) combined with Docetaxl is better than sequential radiotherapy and chemotherapy, while there are no significant differences in adverse reactions between the two treatment.%目的:探讨适形调强放疗联合多西他赛对局部晚期非小细胞肺癌(NSCLC)的疗效及不良反应.方法:将65例NSCLC患者,随机分为A组(35例)和B组(30例).A组35例,采用适形调强放疗联合多西他赛和顺铂同步化疗,放疗后再予以多西他赛及顺铂化疗2个周期;B组30例,采用适形调强放疗结束后,予以多西他赛和顺铂化疗4~6个周期.结果:A组和B组有效率(RR)分别为82.9%和60.0%,两组比较差异有统计学意义,P=0

  18. Cytokine-Induced Modulation of Colorectal Cancer.

    Science.gov (United States)

    Mager, Lukas F; Wasmer, Marie-Hélène; Rau, Tilman T; Krebs, Philippe

    2016-01-01

    The emergence of novel immunomodulatory cancer therapies over the last decade, above all immune checkpoint blockade, has significantly advanced tumor treatment. For colorectal cancer (CRC), a novel scoring system based on the immune cell infiltration in tumors has greatly improved disease prognostic evaluation and guidance to more specific therapy. These findings underline the relevance of tumor immunology in the future handling and therapeutic approach of malignant disease. Inflammation can either promote or suppress CRC pathogenesis and inflammatory mediators, mainly cytokines, critically determine the pro- or anti-tumorigenic signals within the tumor environment. Here, we review the current knowledge on the cytokines known to be critically involved in CRC development and illustrate their mechanisms of action. We also highlight similarities and differences between CRC patients and murine models of CRC and point out cytokines with an ambivalent role for intestinal cancer. We also identify some of the future challenges in the field that should be addressed for the development of more effective immunomodulatory therapies.

  19. Cardiac autonomic modulation in healthy elderly after different intensities of dynamic exercise

    Science.gov (United States)

    Droguett, Viviane Santos López; Santos, Amilton da Cruz; de Medeiros, Carlos Eduardo; Marques, Douglas Porto; do Nascimento, Leone Severino; Brasileiro-Santos, Maria do Socorro

    2015-01-01

    Purpose To investigate the heart rate (HR) and its autonomic modulation at baseline and during dynamic postexercise (PEX) with intensities of 40% and 60% of the maximum HR in healthy elderly. Methods This cross-sectional study included ten apparently healthy people who had been submitted to a protocol on a cycle ergometer for 35 minutes. Autonomic modulation was evaluated by spectral analysis of HR variability (HRV). Results A relevant increase in HR response was observed at 15 minutes postexercise with intensities of 60% and 40% of the maximum HR (10±2 bpm versus 5±1 bpm, respectively; P=0.005), and a significant reduction in HRV was also noted with 40% and 60% intensities during the rest period, and significant reduction in HRV (RR variance) was also observed in 40% and 60% intensities when compared to the baseline, as well as between the post-exercise intensities (1032±32 ms versus 905±5 ms) (P<0.001). In the HRV spectral analysis, a significant increase in the low frequency component HRV and autonomic balance at 40% of the maximum HR (68±2 normalized units [nu] versus 55±1 nu and 2.0±0.1 versus 1.2±0.1; P<0.001) and at 60% of the maximum HR (77±1 nu versus 55±1 nu and 3.2±0.1 versus 1.2±0.1 [P<0.001]) in relation to baseline was observed. A significant reduction of high frequency component at 40% and 60% intensities, however, was observed when compared to baseline (31±2 nu and 23±1 nu versus 45±1 nu, respectively; P<0.001). Moreover, significant differences were observed for the low frequency and high frequency components, as well as for the sympathovagal balance between participants who reached 40% and 60% of the maximum HR. Conclusion There was an increase in the HR, sympathetic modulation, and sympathovagal balance, as well as a reduction in vagal modulation in the elderly at both intensities of the PEX. PMID:25653509

  20. SU-E-J-274: Responses of Medulloblastoma Cells to Radiation Dosimetric Parameters in Intensity-Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Park, J [Dept. of Pediatrics, Stanford University School of Medicine, Stanford, CA (United States); Molecular Imaging Program at Stanford, Stanford, CA (United States); Bio-X Program, Stanford, CA (United States); Research Institute of Biomedical Engineering, The Catholic University of Korea, Seoul (Korea, Republic of); Park, J [Proton Therapy Center, National Cancer Center, Goyang (Korea, Republic of); Rogalla, S; Contag, C [Dept. of Pediatrics, Stanford University School of Medicine, Stanford, CA (United States); Molecular Imaging Program at Stanford, Stanford, CA (United States); Bio-X Program, Stanford, CA (United States); Woo, D [Asan Institute for Life Sciences, Asan Medical Center, Seoul (Korea, Republic of); Lee, D [Research Institute of Biomedical Engineering, The Catholic University of Korea, Seoul (Korea, Republic of); Asan Institute for Life Sciences, Asan Medical Center, Seoul (Korea, Republic of); Park, H [Dept. of Radiation Oncology, Ajou University School of Medicine, Suwon (Korea, Republic of); Suh, T [Research Institute of Biomedical Engineering, The Catholic University of Korea, Seoul (Korea, Republic of); Dept. of Biomedical Engineering, The Catholic University of Korea, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: To evaluate radiation responses of the medulloblastoma cell line Daoy in intensity-modulated radiation therapy (IMRT), quantitative variations to variable radiation dosimetic parameters were tracked by bioluminescent images (BLIs). Methods: The luciferase and green fluorescent protein positive Daoy cells were cultured on dishes. The medulloblastoma cells irradiated to different dose rate, interval of fractionated doses, field margin and misalignment, and dose uniformity in IMRT were monitored using bioluminescent images. The cultured cells were placed into a dedicated acrylic phantom to deliver intensity-modulated fluences and calculate accurate predicted dose distribution. The radiation with dose rate from 0.5 Gy/min to 15 Gy/min was irradiated by adjusting monitor unit per minute and source-to-surface distances. The intervals of fractionated dose delivery were changed considering the repair time of double strand breaks (DSB) revealed by straining of gamma-H2AX.The effect of non-uniform doses on the cells were visualized by registering dose distributions and BLIs. The viability according to dosimetric parameters was correlated with bioluminescent intensities for cross-check of radiation responses. Results: The DSB and cell responses due to the first fractionated dose delivery significantly affected final tumor control rather than other parameters. The missing tumor volumes due to the smaller field margin than the tumor periphery or field misalignment caused relapse of cell responses on BLIs. The dose rate and gradient had effect on initial responses but could not bring out the distinguishable killing effect on cancer cells. Conclusion: Visualized and quantified bioluminescent images were useful to correlate the dose distributions with spatial radiation effects on cells. This would derive the effective combination of dose delivery parameters and fractionation. Radiation responses in particular IMRT configuration could be reflected to image based-dose re-optimization.

  1. Clinical Analysis of Elderly Esophageal Cancer Patients Treated with Intensity Modulated Radiation Therapy and Tegafur Gimeracil Oteracil Potassium Capsule%调强放射治疗同步替吉奥治疗高龄食管癌患者的疗效观察

    Institute of Scientific and Technical Information of China (English)

    王武龙; 赵驭骁; 高文斌; 王春雷; 于柏清; 尤奎雨; 王鑫; 冯建国; 张银梅; 宋丽君; 边增祥

    2015-01-01

    目的:探讨常规分割调强放射治疗同步替吉奥治疗高龄食管癌患者的疗效。方法:选择2011年10月-2013年10月门诊和住院治疗的高龄食管癌患者53例。根据治疗模式不同,分为同步组和对照组,同步组采用调强放射治疗同步替吉奥治疗,对照组采用单纯调强放射治疗。结果:同步组较对照组的副反应略高,但差异无统计学意义(P>0.05);同步组和对照组患者总有效率分别达到84.00%和57.14%,差异有统计学意义(P=0.033);同步组和对照组患者12个月随访期内的中位无进展生存期分别为10.84个月和9.36个月,差异有统计学意义(P=0.044),同步组和对照组患者的1年生存率分别为88.0%和85.7%,差异无统计学意义(P=0.75)。结论:调强放射治疗同步替吉奥治疗高龄食管癌患者的疗效肯定。%Objective:To study the clinical analysis of elderly esophageal cancer patients treated with intensity modulated radiation therapy(IMRT) and Tegafur Gimeracil Oteracil Potassium Capsule.Method:53 elderly esophageal cancer patients from October 2011 to October 2013 were selected. According to the different treatment modalities,they were divided into the synchronous chemotherapy group and the control group,the synchronous chemotherapy group was treated with IMRT and Tegafur Gimeracil Oteracil Potassium Capsule,the control group was treated with IMRT.Result:The side effects of the synchronous chemotherapy group was higher than that of the control group,but the difference had no significant difference between two groups(P>0.05);the total effective rate of the synchronous chemotherapy group was 84.00%,the control group was 57.14%,there was statistically significant difference(P=0.033),the median progression free survival of the synchronous chemotherapy group and control group were 10.84 months and 9.36 months,there was statistically significant difference(P=0.044),the survival rate in one year of the

  2. Salivary Gland Tumors Treated With Adjuvant Intensity-Modulated Radiotherapy With or Without Concurrent Chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Schoenfeld, Jonathan D., E-mail: jdschoenfeld@partners.org [Department of Radiation Oncology, Harvard Radiation Oncology Program, Boston, MA (United States); Sher, David J. [Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, MA (United States); Norris, Charles M. [Department of Surgery, Division of Otolaryngology, Brigham and Women' s Hospital, Boston, MA (United States); Haddad, Robert I.; Posner, Marshall R. [Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA (United States); Department of Medicine, Brigham and Women' s Hospital, Boston, MA (United States); Balboni, Tracy A.; Tishler, Roy B. [Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, MA (United States)

    2012-01-01

    Purpose: To analyze the recent single-institution experience of patients with salivary gland tumors who had undergone adjuvant intensity-modulated radiotherapy (IMRT), with or without concurrent chemotherapy. Patients and Methods: We performed a retrospective analysis of 35 salivary gland carcinoma patients treated primarily at the Dana-Farber Cancer Institute between 2005 and 2010 with surgery and adjuvant IMRT. The primary endpoints were local control, progression-free survival, and overall survival. The secondary endpoints were acute and chronic toxicity. The median follow-up was 2.3 years (interquartile range, 1.2-2.8) among the surviving patients. Results: The histologic types included adenoid cystic carcinoma in 15 (43%), mucoepidermoid carcinoma in 6 (17%), adenocarcinoma in 3 (9%), acinic cell carcinoma in 3 (9%), and other in 8 (23%). The primary sites were the parotid gland in 17 (49%), submandibular glands in 6 (17%), tongue in 4 (11%), palate in 4 (11%), and other in 4 (11%). The median radiation dose was 66 Gy, and 22 patients (63%) received CRT. The most common chemotherapy regimen was carboplatin and paclitaxel (n = 14, 64%). A trend was seen for patients undergoing CRT to have more adverse prognostic factors, including Stage T3-T4 disease (CRT, n = 12, 55% vs. n = 4, 31%, p = .29), nodal positivity (CRT, n = 8, 36% vs. n = 1, 8%, p = .10), and positive margins (n = 13, 59% vs. n = 5, 38%, p = .30). One patient who had undergone CRT developed an in-field recurrence, resulting in an overall actuarial 3-year local control rate of 92%. Five patients (14%) developed distant metastases (1 who had undergone IMRT only and 4 who had undergone CRT). Acute Grade 3 mucositis, esophagitis, and dermatitis occurred in 8%, 8%, and 8% (1 each) of IMRT patients and in 18%, 5%, and 14% (4, 1, and 3 patients) of the CRT group, respectively. No acute Grade 4 toxicity occurred. The most common late toxicity was Grade 1 xerostomia (n = 8, 23%). Conclusions: Treatment of

  3. Multifield Optimization Intensity Modulated Proton Therapy for Head and Neck Tumors: A Translation to Practice

    Energy Technology Data Exchange (ETDEWEB)

    Frank, Steven J., E-mail: sjfrank@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Cox, James D. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Gillin, Michael; Mohan, Radhe [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Garden, Adam S.; Rosenthal, David I.; Gunn, G. Brandon [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Weber, Randal S. [Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Kies, Merrill S. [Department of Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Lewin, Jan S. [Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Munsell, Mark F. [Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Palmer, Matthew B. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Sahoo, Narayan; Zhang, Xiaodong; Liu, Wei; Zhu, X. Ronald [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2014-07-15

    Background: We report the first clinical experience and toxicity of multifield optimization (MFO) intensity modulated proton therapy (IMPT) for patients with head and neck tumors. Methods and Materials: Fifteen consecutive patients with head and neck cancer underwent MFO-IMPT with active scanning beam proton therapy. Patients with squamous cell carcinoma (SCC) had comprehensive treatment extending from the base of the skull to the clavicle. The doses for chemoradiation therapy and radiation therapy alone were 70 Gy and 66 Gy, respectively. The robustness of each treatment plan was also analyzed to evaluate sensitivity to uncertainties associated with variations in patient setup and the effect of uncertainties with proton beam range in patients. Proton beam energies during treatment ranged from 72.5 to 221.8 MeV. Spot sizes varied depending on the beam energy and depth of the target, and the scanning nozzle delivered the spot scanning treatment “spot by spot” and “layer by layer.” Results: Ten patients presented with SCC and 5 with adenoid cystic carcinoma. All 15 patients were able to complete treatment with MFO-IMPT, with no need for treatment breaks and no hospitalizations. There were no treatment-related deaths, and with a median follow-up time of 28 months (range, 20-35 months), the overall clinical complete response rate was 93.3% (95% confidence interval, 68.1%-99.8%). Xerostomia occurred in all 15 patients as follows: grade 1 in 10 patients, grade 2 in 4 patients, and grade 3 in 1 patient. Mucositis within the planning target volumes was seen during the treatment of all patients: grade 1 in 1 patient, grade 2 in 8 patients, and grade 3 in 6 patients. No patient experienced grade 2 or higher anterior oral mucositis. Conclusions: To our knowledge, this is the first clinical report of MFO-IMPT for head and neck tumors. Early clinical outcomes are encouraging and warrant further investigation of proton therapy in prospective clinical trials.

  4. Particle swarm optimizer for weighting factor selection in intensity-modulated radiation therapy optimization algorithms.

    Science.gov (United States)

    Yang, Jie; Zhang, Pengcheng; Zhang, Liyuan; Shu, Huazhong; Li, Baosheng; Gui, Zhiguo

    2017-01-01

    In inverse treatment planning of intensity-modulated radiation therapy (IMRT), the objective function is typically the sum of the weighted sub-scores, where the weights indicate the importance of the sub-scores. To obtain a high-quality treatment plan, the planner manually adjusts the objective weights using a trial-and-error procedure until an acceptable plan is reached. In this work, a new particle swarm optimization (PSO) method which can adjust the weighting factors automatically was investigated to overcome the requirement of manual adjustment, thereby reducing the workload of the human planner and contributing to the development of a fully automated planning process. The proposed optimization method consists of three steps. (i) First, a swarm of weighting factors (i.e., particles) is initialized randomly in the search space, where each particle corresponds to a global objective function. (ii) Then, a plan optimization solver is employed to obtain the optimal solution for each particle, and the values of the evaluation functions used to determine the particle's location and the population global location for the PSO are calculated based on these results. (iii) Next, the weighting factors are updated based on the particle's location and the population global location. Step (ii) is performed alternately with step (iii) until the termination condition is reached. In this method, the evaluation function is a combination of several key points on the dose volume histograms. Furthermore, a perturbation strategy - the crossover and mutation operator hybrid approach - is employed to enhance the population diversity, and two arguments are applied to the evaluation function to improve the flexibility of the algorithm. In this study, the proposed method was used to develop IMRT treatment plans involving five unequally spaced 6MV photon beams for 10 prostate cancer cases. The proposed optimization algorithm yielded high-quality plans for all of the cases, without human

  5. Elective Lymph Node Irradiation With Intensity-Modulated Radiotherapy: Is Conventional Dose Fractionation Necessary?

    Energy Technology Data Exchange (ETDEWEB)

    Bedi, Meena; Firat, Selim; Semenenko, Vladimir A.; Schultz, Christopher; Tripp, Patrick; Byhardt, Roger [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Wang, Dian, E-mail: dwang@mcw.edu [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States)

    2012-05-01

    Purpose: Intensity-modulated radiation therapy (IMRT) is the standard of care for head-and-neck cancer (HNC). We treated patients with HNC by delivering either a moderate hypofractionation (MHF) schedule (66 Gy at 2.2 Gy per fraction to the gross tumor [primary and nodal]) with standard dose fractionation (54-60 Gy at 1.8-2.0 Gy per fraction) to the elective neck lymphatics or a conventional dose and fractionation (CDF) schedule (70 Gy at 2.0 Gy per fraction) to the gross tumor (primary and nodal) with reduced dose to the elective neck lymphatics. We analyzed these two cohorts for treatment outcomes. Methods and Materials: Between November 2001 and February 2009, 89 patients with primary carcinomas of the oral cavity, larynx, oropharynx, hypopharynx, and nasopharynx received definitive IMRT with or without concurrent chemotherapy. Twenty patients were treated using the MHF schedule, while 69 patients were treated with the CDF schedule. Patient characteristics and dosimetry plans were reviewed. Patterns of failure including local recurrence (LR), regional recurrence (RR), distant metastasis (DM), disease-free survival (DFS), overall survival (OS), and toxicities, including rate of feeding tube placement and percentage of weight loss, were reviewed and analyzed. Results: Median follow-up was 31.2 months. Thirty-five percent of patients in the MHF cohort and 77% of patients in the CDF cohort received chemotherapy. No RR was observed in either cohort. OS, DFS, LR, and DM rates for the entire group at 2 years were 89.3%, 81.4%, 7.1%, and 9.4%, respectively. Subgroup analysis showed no significant differences in OS (p = 0.595), DFS (p = 0.863), LR (p = 0.833), or DM (p = 0.917) between these two cohorts. Similarly, no significant differences were observed in rates of feeding tube placement and percentages of weight loss. Conclusions: Similar treatment outcomes were observed for MHF and CDF cohorts. A dose of 50 Gy at 1.43 Gy per fraction may be sufficient to electively

  6. Distant Metastases in Head-and-Neck Squamous Cell Carcinoma Treated With Intensity-Modulated Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Yao Min, E-mail: min.yao@uhhospitals.org [Department of Radiation Oncology, University Hospitals Case Medical Center, Cleveland, OH (United States); Lu Minggen [School of Public Health, University of Nevada at Reno, Reno, NV (United States); Savvides, Panayiotis S. [Department of Medicine, University Hospitals Case Medical Center, Cleveland, OH (United States); Rezaee, Rod; Zender, Chad A.; Lavertu, Pierre [Department of Otolaryngology-Head and Neck Surgery, University Hospitals Case Medical Center, Cleveland, OH (United States); Buatti, John M. [Department of Radiation Oncology, University of Iowa, Iowa City, IA (United States); Machtay, Mitchell [Department of Radiation Oncology, University Hospitals Case Medical Center, Cleveland, OH (United States)

    2012-06-01

    Purpose: To determine the pattern and risk factors for distant metastases in head-and-neck squamous cell carcinoma (HNSCC) after curative treatment with intensity-modulated radiotherapy (IMRT). Methods and Materials: This was a retrospective study of 284 HNSCC patients treated in a single institution with IMRT. Sites included were oropharynx (125), oral cavity (70), larynx (55), hypopharynx (17), and unknown primary (17). American Joint Committee on Cancer stage distribution includes I (3), II (19), III (42), and IV (203). There were 224 males and 60 females with a median age of 57. One hundred eighty-six patients were treated with definitive IMRT and 98 postoperative IMRT. One hundred forty-nine patients also received concurrent cisplatin-based chemotherapy. Results: The median follow-up for all patients was 22.8 months (range, 0.07-77.3 months) and 29.5 months (4.23-77.3 months) for living patients. The 3-year local recurrence-free survival, regional recurrence-free survival, locoregional recurrence-free survival, distant metastasis-free survival, and overall survival were 94.6%, 96.4%, 92.5%, 84.1%, and 68.95%, respectively. There were 45 patients with distant metastasis. In multivariate analysis, distant metastasis was strongly associated with N stage (p = 0.046), T stage (p < 0.0001), and pretreatment maximum standardized uptake value of the lymph node (p = 0.006), but not associated with age, gender, disease sites, pretreatment standardized uptake value of the primary tumor, or locoregional control. The freedom from distant metastasis at 3 years was 98.1% for no factors, 88.6% for one factor, 68.3% for two factors, and 41.7% for three factors (p < 0.0001 by log-rank test). Conclusion: With advanced radiation techniques and concurrent chemotherapy, the failure pattern has changed with more patients failing distantly. The majority of patients with distant metastases had no local or regional failures, indicating that these patients might have microscopic distant

  7. Osteoradionecrosis of the mandible. Minimized risk profile following Intensity-Modulated Radiation Therapy (IMRT)

    Energy Technology Data Exchange (ETDEWEB)

    Studer, G.; Huguenin, P.; Luetolf, U.M.; Glanzmann, C. [Dept. of Radiation Oncology, Univ. Hospital, Zurich (Switzerland); Studer, S.P.; Zwahlen, R.A.; Graetz, K.W. [Dept. of Craniomaxillofacial Surgery, Univ. Hospital, Zurich (Switzerland)

    2006-05-15

    Background and purpose: osteoradionecrosis (ON) of the mandible is a serious late complication of high-dose radiation therapy for tumors of the oropharynx and oral cavity. After doses between 60 and 72 Gy using standard fractionation, an incidence of ON between 5% and 15% is reported in a review from 1989, whereas in more recent publications using moderately accelerated or hyperfractionated irradiation and doses between 69 and 81 Gy, the incidence of ON is between < 1% and {proportional_to} 6%. Intensity-modulated radiation therapy (IMRT) is expected to translate into a further important reduction of ON. The aim of this descriptive study was to assess absolute and relative bone volumes exposed to high IMRT doses, related to observed bone tolerance. Patients and methods: between December 2001 and November 2004, 73 of 123 patients treated with IMRT were identified as subgroup ''at risk'' for ON (> 60 Gy for oropharyngeal or oral cavity cancer). 21/73 patients were treated in a postoperative setting, 52 patients underwent primary definitive irradiation. In 56 patients concomitant cisplatin-based chemotherapy was applied. Mean follow-up time was 22 months (12-46 months). Oral cavity including the mandible bone outside the planning target volume was contoured and dose-volume constraints were defined in order to spare bone tissue. Dose-volume histograms were obtained from contoured mandible in each patient and were analyzed and related to clinical mandible bone tolerance. Results: using IMRT with doses between 60 and 75 Gy (mean 67 Gy), on average 7.8, 4.8, 0.9, and 0.3 cm{sup 3} were exposed to doses > 60, 65, 70, and 75 Gy, respectively. These values are substantially lower than when using three-dimensional conformal radiotherapy. The difference has been approximately quantified by comparison with a historic series. Additional ON risk factors of the patients were also analyzed. Only one grade 3 ON of the lingual horizontal branch, treated with

  8. 不同调强技术在宫颈癌骨髓保护根治性放疗中的应用%Various Techniques of Bone Marrow-Sparing Intensity Modulated Radiation Therapy in Cervical Cancer Treated with Definitive Radiotherapy

    Institute of Scientific and Technical Information of China (English)

    林柏翰; 吴丽丽; 张基永

    2015-01-01

    目的:分析比较固定野调强技术和不同弧数的旋转容积调强在宫颈癌骨髓保护根治性全盆腔放射治疗的剂量学特点,寻找更优的治疗方案。方法:选取在汕头大学医学院附属肿瘤医院接受根治性放疗的ⅡA~ⅢB期宫颈癌患者9例,针对每例患者分别设计九野固定野调强(FF-IMRT)计划、双弧、三弧和四弧旋转容积调强(2A-VMAT、3A-VMAT、4VMAT)计划,比较四者靶区、骨盆骨髓,其他危及器官的剂量学差异和加速器跳数和照射时间。结果:IMRT、2A-VMAT、3A-VMAT和4A-VMAT四组计划均具有良好的靶区覆盖率,靶区适形度和均匀性以及骨盆骨髓受照剂量和受照体积(V10,V20,V40)无差异。三组VMAT计划在危及器官的保护上无差异。VMAT计划的小肠均略低于FF-IMRT计划(P<0.008),在直肠的保护上,FF-IMRT计划略优于3弧VMAT计划(P<0.008)。IMRT、2A-VMAT、3A-VMAT和4A-VMAT计划的加速器跳数分别为(1850.3±227.8)MU、(848.4±58.8)MU、(835.0±76.2)MU和(910.8±43.3)MU,照射时间分别为(353.2±25.1)s、(136.2±3.6)s、(211.2±3.5)s和(286.2±3.4)s。各组的加速器跳数和照射时间比较差异有统计学意义,调强计划的跳数和照射时间最多,两弧VMAT最少。结论:综合考虑各种物理和生物因素,在宫颈癌骨髓保护根治性放疗计划中,双弧VMAT技术照射为最优选择。%Objective: To compare static intensity-modulated radiation therapy (IMRT) technique with various arcs of volumetric-modulated arc radiation therapy (VMAT) techniques in patients with cervical cancer treated with definitive bone morrow-sparing whole pelvic radiotherapy, and to explore a better treatment management.Method: 9 CT image sets of staged ⅡA-ⅢB cervical cancer patients, treated in Cancer Hospital of Shantou University Medical College, were included. Nine fixed-field IMRT (FF-IMRT) plans and two

  9. Module network inference from a cancer gene expression data set identifies microRNA regulated modules.

    Directory of Open Access Journals (Sweden)

    Eric Bonnet

    Full Text Available BACKGROUND: MicroRNAs (miRNAs are small RNAs that recognize and regulate mRNA target genes. Multiple lines of evidence indicate that they are key regulators of numerous critical functions in development and disease, including cancer. However, defining the place and function of miRNAs in complex regulatory networks is not straightforward. Systems approaches, like the inference of a module network from expression data, can help to achieve this goal. METHODOLOGY/PRINCIPAL FINDINGS: During the last decade, much progress has been made in the development of robust and powerful module network inference algorithms. In this study, we analyze and assess experimentally a module network inferred from both miRNA and mRNA expression data, using our recently developed module network inference algorithm based on probabilistic optimization techniques. We show that several miRNAs are predicted as statistically significant regulators for various modules of tightly co-expressed genes. A detailed analysis of three of those modules demonstrates that the specific assignment of miRNAs is functionally coherent and supported by literature. We further designed a set of experiments to test the assignment of miR-200a as the top regulator of a small module of nine genes. The results strongly suggest that miR-200a is regulating the module genes via the transcription factor ZEB1. Interestingly, this module is most likely involved in epithelial homeostasis and its dysregulation might contribute to the malignant process in cancer cells. CONCLUSIONS/SIGNIFICANCE: Our results show that a robust module network analysis of expression data can provide novel insights of miRNA function in important cellular processes. Such a computational approach, starting from expression data alone, can be helpful in the process of identifying the function of miRNAs by suggesting modules of co-expressed genes in which they play a regulatory role. As shown in this study, those modules can then be

  10. System design of programmable 4f phase modulation techniques for rapid intensity shaping: a conceptual comparison

    Science.gov (United States)

    Roth, Matthias; Heber, Jörg; Janschek, Klaus

    2016-03-01

    The present study analyses three beam shaping approaches with respect to a light-efficient generation of i) patterns and ii) multiple spots by means of a generic optical 4f-setup. 4f approaches share the property that due to the one-to-one relationship between output intensity and input phase, the need for time-consuming, iterative calculation can be avoided. The resulting low computational complexity offers a particular advantage compared to the widely used holographic principles and makes them potential candidates for real-time applications. The increasing availability of high-speed phase modulators, e.g. on the basis of MEMS, calls for an evaluation of the performances of these concepts. Our second interest is the applicability of 4f methods to high-power applications. We discuss the variants of 4f intensity shaping by phase modulation from a system-level point of view which requires the consideration of application relevant boundary conditions. The discussion includes i) the micro mirror based phase manipulation combined with amplitude masking in the Fourier plane, ii) the Generalized Phase Contrast, and iii) matched phase-only correlation filtering combined with GPC. The conceptual comparison relies on comparative figures of merit for energy efficiency, pattern homogeneity, pattern image quality, maximum output intensity and flexibility with respect to the displayable pattern. Numerical simulations illustrate our findings.

  11. Stromal Modulators of TGF-β in Cancer

    Science.gov (United States)

    Costanza, Brunella; Umelo, Ijeoma Adaku; Bellier, Justine; Castronovo, Vincent; Turtoi, Andrei

    2017-01-01

    Transforming growth factor-β (TGF-β) is an intriguing cytokine exhibiting dual activities in malignant disease. It is an important mediator of cancer invasion, metastasis and angiogenesis, on the one hand, while it exhibits anti-tumor functions on the other hand. Elucidating the precise role of TGF-β in malignant development and progression requires a better understanding of the molecular mechanisms involved in its tumor suppressor to tumor promoter switch. One important aspect of TGF-β function is its interaction with proteins within the tumor microenvironment. Several stromal proteins have the natural ability to interact and modulate TGF-β function. Understanding the complex interplay between the TGF-β signaling network and these stromal proteins may provide greater insight into the development of novel therapeutic strategies that target the TGF-β axis. The present review highlights our present understanding of how stroma modulates TGF-β activity in human cancers. PMID:28067804

  12. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT)

    Energy Technology Data Exchange (ETDEWEB)

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham [Andrew Love Cancer Centre, Geelong Hospital, Geelong, Victoria (Australia)

    2013-12-15

    Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147–53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose–volume histogram (DVH) doses were consistently lower. The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques.

  13. Dietary energy balance modulates ovarian cancer progression and metastasis.

    Science.gov (United States)

    Al-Wahab, Zaid; Tebbe, Calvin; Chhina, Jasdeep; Dar, Sajad A; Morris, Robert T; Ali-Fehmi, Rouba; Giri, Shailendra; Munkarah, Adnan R; Rattan, Ramandeep

    2014-08-15

    A high energy balance, or caloric excess, accounts as a tumor promoting factor, while a negative energy balance via caloric restriction, has been shown to delay cancer progression. The effect of energy balance on ovarian cancer progression was investigated in an isogeneic immunocompetent mouse model of epithelial ovarian cancer kept on a regimen of regular diet, high energy diet (HED) and calorie restricted diet (CRD), prior to inoculating the animals intraperitoneally with the mouse ovarian surface epithelial ID8 cancer cells. Tumor evaluation revealed that mice group on HED displayed the most extensive tumor formation with the highest tumor score at all organ sites (diaphragm, peritoneum, bowel, liver, kidney, spleen), accompanied with increased levels of insulin, leptin, insulin growth factor-1 (IGF-1), monocyte chemoattractant protein-1 (MCP-1), VEGF and interleukin 6 (IL-6). On the other hand, the mice group on CRD exhibited the least tumor burden associated with a significant reduction in levels of insulin, IGF-1, leptin, MCP-1, VEGF and IL-6. Immunohistochemistry analysis of tumors from HED mice showed higher activation of Akt and mTOR with decreased adenosine monophosphate activated kinase (AMPK) and SIRT1 activation, while tumors from the CRD group exhibited the reverse profile. In conclusion, ovarian cancer growth and metastasis occurred more aggressively under HED conditions and was significantly curtailed under CRD. The suggested mechanism involves modulated secretion of growth factors, cytokines and altered regulation of AMPK and SIRT1 that converges on mTOR inhibition. While the role of a high energy state in ovarian cancer has not been confirnmed in the literature, the current findings support investigating the potential impact of diet modulation as adjunct to other anticancer therapies and as possible individualized treatment strategy of epithelial ovarian cancer.

  14. 宫颈癌术后三维适形放疗和共面等分设野调强放疗计划的对比分析%Dosimetric study of postoperative 3-dimensional conformal radiotherapy and coplanar decile intensity-modulated radiotherapy for cervical cancer

    Institute of Scientific and Technical Information of China (English)

    蒋军; 张利文; 廖珊; 黄荣

    2012-01-01

    目的 探讨宫颈癌术后三维适形放射治疗(3D-CRT)和共面等分设野调强放射治疗(IMRT)计划靶区及其周围危及器官受照剂量的差异.方法 随机选择10例宫颈癌术后患者,进行CT扫描、靶区和危及器官的勾画,处方剂量50 Gy.分别进行3D-CRT和共面等分设野IMRT计划设计,计算靶区剂量均匀度指数(HI)、适形度指数(CI)、最大受照剂量、最小受照剂量、平均受照剂量和危及器官照射体积等并对结果进行比较分析.结果 5F-IMRT、7F-IMRT和9F-IMRT在靶区适形度方面明显优于3D-CRT;在危及器官(膀胱V30 、V40 、V50,小肠V50和直肠V30、V40、V50)保护方面,5F-IMRT、7F-IMRT和9F-IMRT明显优于3D-CRT,P<0.05.而各IMRT计划之间差异无统计学意义,P>0.05.结论 宫颈癌术后辅助放疗共面等分IMRT计划无论在靶区适形度还是正常组织保护方面均优于3D-CRT,同时也证实7野或9野IMRT未必较5野获益更多.5野与7、9野的IMRT相比、在治疗时间及费用方面有独特的优势,值得在临床上推广.%Objective To compare the difference of the dose distribution in clinical target volume and organ at risk (OAR) between coplanar decile field intensity-modulated radiotherapy (IMRT) and conventional three-dimensional conformal radiotherapy (3D-CRT) for postoperative radiotherapy of cervical cancer. Methods Ten postoperative patients with cervical cancer were selected randomly to undergo CT scan and planning target volume (PTV) and OAR contouring. 3D-CRT and coplanar decile IMRT planning was performed for each patient with a prescribed dose of 50 Gy. The homogeneity index (HI), conformity index (CI), maximum dose, minimum dose, mean dose of PTV, and irradiated volume of OARs were calculated and the results were compared. Results 5-field IMRT, 7-field IMRT and 9-field IMRT plans had a significant better conformity index (CI) of PTV compared with 3D-CRT (P0.05). Conclusion Coplanar decile IMRT plans is superior

  15. Intensity-modulated radiotherapy combined with gemcitabine and cisplatin chemotherapy for local advanced non-small cell lung cancer%调强放疗联合吉西他滨加顺铂治疗局部晚期非小细胞肺癌临床观察

    Institute of Scientific and Technical Information of China (English)

    饶建

    2015-01-01

    目的 观察调强放射治疗联合吉西他滨、顺铂同步化疗治疗局部晚期非小细胞肺癌疗效与安全性.方法 回顾分析2012年1月至2014年6月在我院肿瘤科行调强放疗的45例局部晚期NSCLC患者.给予调强放疗,处方剂量为PTV 50.4 Gy/28次,常规分割,同步GTV推量,PTV-GTV为60 Gy/28次.同步给予化疗,方案为吉西他滨加顺铂,方案为放疗第1d起开始化疗,吉西他滨1.0 g/m2,dl、d8,顺铂25 mg/m2,dl ~3,每21d重复.放疗后再采用该方案化疗4个周期.主要观察指标为总有效率(ORR)、毒副反应.结果 所有患者按计划完成治疗.近期疗效CR 6例,PR 26例,SD 12例,PD 1例.ORR 71.1%.毒副反应主要为恶心、呕吐、骨髓抑制,放射性食管炎,放射性肺炎.结论 调强放疗联合吉西他滨加顺铂同步化疗治疗局部晚期NSCLC近期疗效好,毒副反应可耐受,长期疗效有待进一步随访研究.%Objective To evaluate the clinical efficacy and toxicities of intensity-modulated radiotherapy(IMRT) combined with gemcitabine and cisplatin chemotherapy for patients with locally advanced non-small cell lung cancer(NSCLC).Method Forty five patients with NSCLC who received IMRT from January,2012 to June,2014 in our hospital were retrospectively analyzed.The IMRT plans were designed to deliver 50.4G y/28 f to PTV while delivering 60 Gy/28 f to GTV.Chemotherapy was given from the first day of IMRT,with gemcitabine 1.0 g/m2 on day l to day 8 and cisplatin 25my/m2 on day 1 to day 3.The chemothtrapy was repeated every 21 days,with a total of 4 cycles.The endpoints were overall response rate(ORR) and adverse events.Results All patients completed definitive IMRT and chemotherapy.Complete response(CR),partial response(PR),stable disease(SD),and progressive disease(PD)were observed in 6,26,12,and 1 cases,respectively,with a ORR of 71.1%.The main toxicities were tolerable,which included myelosuppression,nausea,vomiting,acute radiation pneumonia,and acute

  16. Dosimetric Comparison of Three-Dimensional Conformal Proton Radiotherapy, Intensity-Modulated Proton Therapy, and Intensity-Modulated Radiotherapy for Treatment of Pediatric Craniopharyngiomas

    Energy Technology Data Exchange (ETDEWEB)

    Boehling, Nicholas S. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Grosshans, David R., E-mail: dgrossha@mdanderson.org [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Bluett, Jaques B. [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Palmer, Matthew T. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Song, Xiaofei; Amos, Richard A.; Sahoo, Narayan [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Meyer, Jeffrey J.; Mahajan, Anita; Woo, Shiao Y. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

    2012-02-01

    Purpose: Cranial irradiation in pediatric patients is associated with serious long-term adverse effects. We sought to determine whether both three-dimensional conformal proton radiotherapy (3D-PRT) and intensity-modulated proton therapy (IMPT) compared with intensity-modulated radiotherapy (IMRT) decrease integral dose to brain areas known to harbor neuronal stem cells, major blood vessels, and other normal brain structures for pediatric patients with craniopharyngiomas. Methods and Materials: IMRT, forward planned, passive scattering proton, and IMPT plans were generated and optimized for 10 pediatric patients. The dose was 50.4 Gy (or cobalt Gy equivalent) delivered in 28 fractions with the requirement for planning target volume (PTV) coverage of 95% or better. Integral dose data were calculated from differential dose-volume histograms. Results: The PTV target coverage was adequate for all modalities. IMRT and IMPT yielded the most conformal plans in comparison to 3D-PRT. Compared with IMRT, 3D-PRT and IMPT plans had a relative reduction of integral dose to the hippocampus (3D-PRT, 20.4; IMPT, 51.3%{sup Asterisk-Operator }), dentate gyrus (27.3, 75.0%{sup Asterisk-Operator }), and subventricular zone (4.5, 57.8%{sup Asterisk-Operator }). Vascular organs at risk also had reduced integral dose with the use of proton therapy (anterior cerebral arteries, 33.3{sup Asterisk-Operator }, 100.0%{sup Asterisk-Operator }; middle cerebral arteries, 25.9%{sup Asterisk-Operator }, 100%{sup Asterisk-Operator }; anterior communicating arteries, 30.8{sup Asterisk-Operator }, 41.7%{sup Asterisk-Operator }; and carotid arteries, 51.5{sup Asterisk-Operator }, 77.6{sup Asterisk-Operator }). Relative reduction of integral dose to the infratentorial brain (190.7{sup Asterisk-Operator }, 109.7%{sup Asterisk-Operator }), supratentorial brain without PTV (9.6, 26.8%{sup Asterisk-Operator }), brainstem (45.6, 22.4%{sup Asterisk-Operator }), and whole brain without PTV (19.4{sup Asterisk

  17. Layered ACO-OFDM for intensity-modulated direct-detection optical wireless transmission.

    Science.gov (United States)

    Wang, Qi; Qian, Chen; Guo, Xuhan; Wang, Zhaocheng; Cunningham, David G; White, Ian H

    2015-05-04

    Layered asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) with high spectral efficiency is proposed in this paper for optical wireless transmission employing intensity modulation with direct detection. In contrast to the conventional ACO-OFDM, which only utilizes odd subcarriers for modulation, leading to an obvious spectral efficiency loss, in layered ACO-OFDM, the subcarriers are divided into different layers and modulated by different kinds of ACO-OFDM, which are combined for simultaneous transmission. In this way, more subcarriers are used for data transmission and the spectral efficiency is improved. An iterative receiver is also proposed for layered ACO-OFDM, where the negative clipping distortion of each layer is subtracted once it is detected so that the signals from different layers can be recovered. Theoretical analysis shows that the proposed scheme can improve the spectral efficiency by up to 2 times compared with conventional ACO-OFDM approaches with the same modulation order. Meanwhile, simulation results confirm a considerable signal-to-noise ratio gain over ACO-OFDM at the same spectral efficiency.