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Sample records for intensity modulation radiotherapy

  1. Intensity-modulated radiotherapy in the treatment of gynaecological cancers.

    PubMed

    D'Souza, D P; Rumble, R B; Fyles, A; Yaremko, B; Warde, P

    2012-09-01

    Intensity-modulated radiotherapy (IMRT) is a newer method of radiotherapy that uses intensity-modulated beams that can provide multiple intensity levels for any single beam direction and any single source position allowing concave dose distributions and dose gradients with narrower margins than those possible using conventional methods. IMRT is ideal for treating complex treatment volumes and avoiding close proximity organs at risk that may be dose limiting and provides increased tumour control through an escalated dose and reduces normal tissue complications through organ at risk sparing. Given the potential advantages of IMRT and the availability of IMRT-enabled treatment planning systems and linear accelerators, IMRT has been introduced in a number of disease sites. This systematic review examined the evidence for IMRT in the treatment of gynaecological cancers to quantify the potential benefits of this new technology and to make recommendations for radiation treatment programmes considering adopting this technique. Findings were based on a review of four cohort studies, one of which was prospective, including a total of 619 patients. If reducing acute and chronic toxicity are the main outcomes of interest, then IMRT may be considered over three-dimensional conformal radiotherapy for women with gynaecological cancers; if disease-related outcomes are the main outcomes of interest, there are insufficient data to recommend IMRT over three-dimensional conformal radiotherapy. Future research should focus on prospective multicentre studies reporting on both acute and chronic toxicity as well as survival and recurrence. Dose escalation studies should be carried out to investigate the effect of higher doses on disease.

  2. Intensity-modulated radiotherapy in the treatment of prostate cancer.

    PubMed

    Bauman, G; Rumble, R B; Chen, J; Loblaw, A; Warde, P

    2012-09-01

    Three-dimensional conformal radiotherapy (3DCRT) as the primary treatment for prostate cancer has improved outcomes compared with conventional radiotherapy, but with an associated increase in toxicity due to radiation effects on the bladder and rectum. Intensity-modulated radiotherapy (IMRT) is a newer method of radiotherapy that uses intensity-modulated beams that can provide multiple intensity levels for any single beam direction and any single source position allowing concave dose distributions and dose gradients with narrower margins than those possible using conventional methods. IMRT is ideal for treating complex treatment volumes and avoiding close proximity organs at risk that may be dose limiting and provides increased tumour control through an escalated dose and reduces normal tissue complications through organ at risk sparing. Given the potential advantages of IMRT and the availability of IMRT-enabled treatment planning systems and linear accelerators, IMRT has been introduced in a number of disease sites, including prostate cancer. This systematic review examined the evidence for IMRT in the treatment of prostate cancer in order to quantify the potential benefits of this new technology and to make recommendations for radiation treatment programmes considering adopting this technique. The findings were in favour of recommending IMRT over 3DCRT in the radical treatment of localised prostate cancer where doses greater than 70 Gy are required, based on a review of 11 published reports including 4559 patients. There were insufficient data to recommend IMRT over 3DCRT in the postoperative setting. Future research should examine image-guided IMRT in the post-prostatectomy setting, with altered fractionation, and in combination with hormone and chemotherapy.

  3. Intensity-Modulated Radiotherapy for Sinonasal Cancer: Improved Outcome Compared to Conventional Radiotherapy

    SciTech Connect

    Dirix, Piet; Vanstraelen, Bianca; Jorissen, Mark; Vander Poorten, Vincent; Nuyts, Sandra

    2010-11-15

    Purpose: To evaluate clinical outcome and toxicity of postoperative intensity-modulated radiotherapy (IMRT) for malignancies of the nasal cavity and paranasal sinuses. Methods and Materials: Between 2003 and 2008, 40 patients with cancer of the paranasal sinuses (n = 34) or nasal cavity (n = 6) received postoperative IMRT to a dose of 60 Gy (n = 21) or 66 Gy (n = 19). Treatment outcome and toxicity were retrospectively compared with that of a previous patient group (n = 41) who were also postoperatively treated to the same doses but with three-dimensional conformal radiotherapy without intensity modulation, from 1992 to 2002. Results: Median follow-up was 30 months (range, 4-74 months). Two-year local control, overall survival, and disease-free survival were 76%, 89%, and 72%, respectively. Compared to the three-dimensional conformal radiotherapy treatment, IMRT resulted in significantly improved disease-free survival (60% vs. 72%; p = 0.02). No grade 3 or 4 toxicity was reported in the IMRT group, either acute or chronic. The use of IMRT significantly reduced the incidence of acute as well as late side effects, especially regarding skin toxicity, mucositis, xerostomia, and dry-eye syndrome. Conclusions: Postoperative IMRT for sinonasal cancer significantly improves disease-free survival and reduces acute as well as late toxicity. Consequently, IMRT should be considered the standard treatment modality for malignancies of the nasal cavity and paranasal sinuses.

  4. [Feasibility of Automatic Treatment Planning in Intensity-modulated Radiotherapy of Nasopharyngeal Carcinoma].

    PubMed

    He, Yinbo; Zhang, Longbin; Xiao, Jianghong; Duan, Baofeng

    2015-12-01

    Intensity-modulated radiotherapy planning for nasopharyngeal carcinoma is very complex. The quality of plan is often closely linked to the experience of the treatment planner. In this study, 10 nasopharyngeal carcinoma patients at different stages were enrolled. Based on the scripting of Pinnacle 9. 2 treatment planning system, the computer program was used to set the basic parameters and objective parameters of the plans. At last, the nasopharyngeal carcinoma intensity-modulated radiotherapy plans were completed automatically. Then, the automatical and manual intensity-modulated radiotherapy plans were statistically compared and clinically evaluated. The results showed that there were no significant differences between those two kinds of plans with respect to the dosimetry parameters of most targets and organs at risk. The automatical nasopharyngeal carcinoma intensity-modulated radiotherapy plans can meet the requirements of clinical radiotherapy, significantly reduce planning time, and avoid the influence of human factors such as lack of experience to the quality of plan. PMID:27079103

  5. Prostate Bed Motion During Intensity-Modulated Radiotherapy Treatment

    SciTech Connect

    Klayton, Tracy; Price, Robert; Buyyounouski, Mark K.; Sobczak, Mark; Greenberg, Richard; Li, Jinsheng; Keller, Lanea; Sopka, Dennis; Kutikov, Alexander; Horwitz, Eric M.

    2012-09-01

    Purpose: Conformal radiation therapy in the postprostatectomy setting requires accurate setup and localization of the prostatic fossa. In this series, we report prostate bed localization and motion characteristics, using data collected from implanted radiofrequency transponders. Methods and Materials: The Calypso four-dimensional localization system uses three implanted radiofrequency transponders for daily target localization and real-time tracking throughout a course of radiation therapy. We reviewed the localization and tracking reports for 20 patients who received ultrasonography-guided placement of Calypso transponders within the prostate bed prior to a course of intensity-modulated radiation therapy at Fox Chase Cancer Center. Results: At localization, prostate bed displacement relative to bony anatomy exceeded 5 mm in 9% of fractions in the anterior-posterior (A-P) direction and 21% of fractions in the superior-inferior (S-I) direction. The three-dimensional vector length from skin marks to Calypso alignment exceeded 1 cm in 24% of all 652 fractions with available setup data. During treatment, the target exceeded the 5-mm tracking limit for at least 30 sec in 11% of all fractions, generally in the A-P or S-I direction. In the A-P direction, target motion was twice as likely to move posteriorly, toward the rectum, than anteriorly. Fifteen percent of all treatments were interrupted for repositioning, and 70% of patients were repositioned at least once during their treatment course. Conclusion: Set-up errors and motion of the prostatic fossa during radiotherapy are nontrivial, leading to potential undertreatment of target and excess normal tissue toxicity if not taken into account during treatment planning. Localization and real-time tracking of the prostate bed via implanted Calypso transponders can be used to improve the accuracy of plan delivery.

  6. Prospective Trial of Accelerated Partial Breast Intensity-Modulated Radiotherapy

    SciTech Connect

    Leonard, Charles . E-mail: charles.leonard@usoncology.com; Carter, Dennis; Kercher, Jane; Howell, Kathryn; Henkenberns, Phyllis; Tallhamer, Michael; Cornish, Patricia C.; Hunter, Kari C.; Kondrat, Janis

    2007-04-01

    Purpose: To examine the feasibility and acute toxicities of an accelerated, partial breast, intensity-modulated radiotherapy (IMRT) protocol. Methods and Materials: Between February 2004 and August 2005, 55 patients with Stage I breast cancer and initial follow-up were enrolled at four facilities on a HealthONE and Western institutional review board-approved accelerated partial breast IMRT protocol. All patients were treated in 10 equal fractions delivered twice daily within 5 consecutive days. The first 7 patients were treated to 34 Gy, and the remaining 48 patients were treated to 38.5 Gy. Results: The median follow-up after IMRT was 10 months (range, <1-19) and after diagnosis was 11.5 months (range, 2-21). No local or distant recurrences developed. The T stage distribution was as follows: T1a in 11 patients, T1b in 24, and T1c in 20. The median tumor size was 9 mm (range, 1-20 mm). Breast cosmesis was judged by the patient as poor by 2, good by 12, and excellent by 40 (1 patient was legally blind) and by the physician as poor for 1, good for 10, and excellent for 44 patients. Breast pain, as judged by patient, was none in 34, mild in 19, moderate in 2, and severe in 0 patients. There was a single report of telangiectasia but no incidents of significant edema. Compared with historic controls for whom three-dimensional treatment planning techniques were used, IMRT provided similar dose delivery to the target while reducing the volume of normal breast included in the 100%, 75%, and 50% isodose lines. Conclusion: This initial report prospectively explored the feasibility of accelerated partial breast IMRT. After short-term follow-up, the dose delivery and clinical outcomes were very acceptable. We believe this regimen deserves additional investigation under institutional review board guidance.

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

    SciTech Connect

    Wang, B; Jin, L; Li, J; Chen, L; Ma, C; Fan, J; Zhang, C

    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.

  8. Intensity modulated neutron radiotherapy optimization by photon proxy

    SciTech Connect

    Snyder, Michael; Hammoud, Ahmad; Bossenberger, Todd; Spink, Robyn; Burmeister, Jay

    2012-08-15

    Purpose: Introducing intensity modulation into neutron radiotherapy (IMNRT) planning has the potential to mitigate some normal tissue complications seen in past neutron trials. While the hardware to deliver IMNRT plans has been in use for several years, until recently the IMNRT planning process has been cumbersome and of lower fidelity than conventional photon plans. Our in-house planning system used to calculate neutron therapy plans allows beam weight optimization of forward planned segments, but does not provide inverse optimization capabilities. Commercial treatment planning systems provide inverse optimization capabilities, but currently cannot model our neutron beam. Methods: We have developed a methodology and software suite to make use of the robust optimization in our commercial planning system while still using our in-house planning system to calculate final neutron dose distributions. Optimized multileaf collimator (MLC) leaf positions for segments designed in the commercial system using a 4 MV photon proxy beam are translated into static neutron ports that can be represented within our in-house treatment planning system. The true neutron dose distribution is calculated in the in-house system and then exported back through the MATLAB software into the commercial treatment planning system for evaluation. Results: The planning process produces optimized IMNRT plans that reduce dose to normal tissue structures as compared to 3D conformal plans using static MLC apertures. The process involves standard planning techniques using a commercially available treatment planning system, and is not significantly more complex than conventional IMRT planning. Using a photon proxy in a commercial optimization algorithm produces IMNRT plans that are more conformal than those previously designed at our center and take much less time to create. Conclusions: The planning process presented here allows for the optimization of IMNRT plans by a commercial treatment planning

  9. Dosimetric comparison of stereotactic radiosurgery to intensity modulated radiotherapy.

    PubMed

    Kramer, B A; Wazer, D E; Engler, M J; Tsai, J S; Ling, M N

    1998-01-01

    To compare the dosimetry achievable with an intensity modulated radiotherapy (IMR) system to that of stereotactic radiosurgery (SRS) for an irregularly shaped moderate size target. A treatment plan was selected from 109 single fraction SRS cases having had multiple non-coplanar arc therapy using a 6 MV linear accelerator fitted with circular tertiary collimators 1.00 to 4.00 cm in diameter at isocenter. The CT scan with delineated regions of interest was then entered into an IMR treatment planning system and optimized dose distributions, using a back projection technique for dynamic multileaf collimator delivery, were generated with a stimulated annealing algorithm. Dose volume histograms (DVH), homogeneity indices (HI), conformity indices (CI), minimum and maximum doses to surrounding highly sensitive intracranial structures, as well as the volume of tissue treated to > 80, 50, and 20% of the prescription dose from the IMR plan were then compared to those from the single isocenter SRS plan used and a hypothetical three isocenter SRS plan. For an irregularly shaped target, the IMR plan produced a HI of 1.08 and CI of 1.50 compared to 1.75 and 4.41, respectively, for the single isocenter SRS plan (SRS1) and 3.33 and 3.43 for the triple isocenter SRS plan (SRS3). The maximum and minimum doses to surrounding critical structures were less with the IMR plan in comparison to both SRS plans. However, the volume of non-target tissue treated to > 80, 50, and 20% of the prescription dose with the IMR plan was 137, 170, and 163%, respectively, of that treated with the SRS1 plan and 85, 100, and 123% of the volume when compared to SRS3 plan. The IMR system provided more conformal target doses than were provided by the single isocenter or three isocenter SRS plans. IMR delivered less dose to critical normal tissues and provided increased homogeneity within the target volume for a moderate size irregularly shaped target, at the cost of a larger penumbra. PMID:9503486

  10. Radiation-Induced Cancers From Modern Radiotherapy Techniques: Intensity-Modulated Radiotherapy Versus Proton Therapy

    SciTech Connect

    Yoon, Myonggeun; Ahn, Sung Hwan; Kim, Jinsung; Shin, Dong Ho; Park, Sung Yong; Lee, Se Byeong; Shin, Kyung Hwan; Cho, Kwan Ho

    2010-08-01

    Purpose: To assess and compare secondary cancer risk resulting from intensity-modulated radiotherapy (IMRT) and proton therapy in patients with prostate and head-and-neck cancer. Methods and Materials: Intensity-modulated radiotherapy and proton therapy in the scattering mode were planned for 5 prostate caner patients and 5 head-and-neck cancer patients. The secondary doses during irradiation were measured using ion chamber and CR-39 detectors for IMRT and proton therapy, respectively. Organ-specific radiation-induced cancer risk was estimated by applying organ equivalent dose to dose distributions. Results: The average secondary doses of proton therapy for prostate cancer patients, measured 20-60cm from the isocenter, ranged from 0.4 mSv/Gy to 0.1 mSv/Gy. The average secondary doses of IMRT for prostate patients, however, ranged between 3 mSv/Gy and 1 mSv/Gy, approximately one order of magnitude higher than for proton therapy. Although the average secondary doses of IMRT were higher than those of proton therapy for head-and-neck cancers, these differences were not significant. Organ equivalent dose calculations showed that, for prostate cancer patients, the risk of secondary cancers in out-of-field organs, such as the stomach, lungs, and thyroid, was at least 5 times higher for IMRT than for proton therapy, whereas the difference was lower for head-and-neck cancer patients. Conclusions: Comparisons of organ-specific organ equivalent dose showed that the estimated secondary cancer risk using scattering mode in proton therapy is either significantly lower than the cases in IMRT treatment or, at least, does not exceed the risk induced by conventional IMRT treatment.

  11. Dosimetric comparison of intensity modulated radiotherapy techniques and standard wedged tangents for whole breast radiotherapy.

    PubMed

    Fong, Andrew; Bromley, Regina; Beat, Mardi; Vien, Din; Dineley, Jude; Morgan, Graeme

    2009-02-01

    Prior to introducing intensity modulated radiotherapy (IMRT) for whole breast radiotherapy (WBRT) into our department we undertook a comparison of the dose parameters of several IMRT techniques and standard wedged tangents (SWT). Our aim was to improve the dose distribution to the breast and to decrease the dose to organs at risk (OAR): heart, lung and contralateral breast (Contra Br). Treatment plans for 20 women (10 right-sided and 10 left-sided) previously treated with SWT for WBRT were used to compare (a) SWT; (b) electronic compensators IMRT (E-IMRT); (c) tangential beam IMRT (T-IMRT); (d) coplanar multi-field IMRT (CP-IMRT); and (e) non-coplanar multi-field IMRT (NCP-IMRT). Plans for the breast were compared for (i) dose homogeneity (DH); (ii) conformity index (CI); (iii) mean dose; (iv) maximum dose; (v) minimum dose; and dose to OAR were calculated (vi) heart; (vii) lung and (viii) Contra Br. Compared with SWT, all plans except CP-IMRT gave improvement in at least two of the seven parameters evaluated. T-IMRT and NCP-IMRT resulted in significant improvement in all parameters except DH and both gave significant reduction in doses to OAR. As on initial evaluation NCP-IMRT is likely to be too time consuming to introduce on a large scale, T-IMRT is the preferred technique for WBRT for use in our department. PMID:19453534

  12. Whole pelvic radiotherapy for prostate cancer using 3D conformal and intensity-modulated radiotherapy

    SciTech Connect

    Ashman, Jonathan B.; Zelefsky, Michael J. . E-mail: zelefskm@mskcc.org; Hunt, Margie S.; Leibel, Steven A.; Fuks, Zvi

    2005-11-01

    Purpose: To investigate the correlations between observed clinical morbidity and dosimetric parameters for whole pelvic radiotherapy (WPRT) for prostate cancer using either three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT). Methods and Materials: Between December 1996 and January 2002, 27 patients with prostate adenocarcinoma were treated with conformal WPRT as part of their definitive treatment. WPRT was delivered with 3D-CRT in 14 patients and with IMRT in 13 patients. For each of the patients treated with IMRT, optimized conventional two-dimensional (2D) and 3D-CRT plans were retrospectively generated for the whole pelvic phase of the treatment. Dose-volume histograms for the bowel, bladder, and rectum were compared for the three techniques. Acute toxicities were evaluated for all 27 patients, and late toxicities were evaluated for 25 patients with sufficient follow-up. Toxicities were scored according to the Radiation Therapy Oncology Group morbidity grading scales. Median follow-up was 30 months. Results: Three-dimensional-CRT resulted in a 40% relative reduction (p < 0.001) in the volume of bowel receiving 45 Gy compared with 2D, and IMRT provided a further 60% reduction relative to 3D-CRT (p < 0.001). Compared with either 2D or 3D-CRT, IMRT reduced the volume of rectum receiving 45 Gy by 90% (p < 0.001). Overall, 9 patients (33%) experienced acute Grade 2 gastrointestinal (GI) toxicity, and only 1 of these patients was treated with IMRT. Antidiarrhea medication was required for 6 patients (22%). However, 5 of these 6 patients also received chemotherapy, and none were treated with IMRT. No Grade 3 or higher acute or late GI toxicities were observed. No cases of late radiation enteritis were observed. Acute and late genitourinary toxicity did not appear significantly increased by the addition of conformal WPRT. Conclusions: Compared to conventional 2D planning, conformal planning for WPRT resulted in significant

  13. Dosimetric comparison of three-dimensional conformal radiotherapy, intensity modulated radiotherapy, and helical tomotherapy for lung stereotactic body radiotherapy

    PubMed Central

    Kinhikar, Rajesh Ashok; Ghadi, Yogesh G.; Sahoo, Priyadarshini; Laskar, Sarbani Ghosh; Deshpande, Deepak D.; Shrivastava, Shyam K.; Agarwal, Jaiprakash

    2015-01-01

    To compare the treatment plans generated with three-dimensional conformal radiation therapy (3DCRT), intensity modulated radiotherapy (IMRT), and helical tomotherapy (HT) for stereotactic body radiotherapy of lung, twenty patients with medically inoperable (early nonsmall cell lung cancer) were retrospectively reviewed for dosimetric evaluation of treatment delivery techniques (3DCRT, IMRT, and HT). A dose of 6 Gy per fraction in 8 fractions was prescribed to deliver 95% of the prescription dose to 95% volume of planning target volume (PTV). Plan quality was assessed using conformity index (CI) and homogeneity index (HI). Doses to critical organs were assessed. Mean CI with 3DCRT, IMRT, and HT was 1.19 (standard deviation [SD] 0.13), 1.18 (SD 0.11), and 1.08 (SD 0.04), respectively. Mean HI with 3DCRT, IMRT, and HT was 1.14 (SD 0.05), 1.08 (SD 0.02), and 1.07 (SD 0.04), respectively. Mean R50% values for 3DCRT, IMRT, and HT was 8.5 (SD 0.35), 7.04 (SD 0.45), and 5.43 (SD 0.29), respectively. D2cm was found superior with IMRT and HT. Significant sparing of critical organs can be achieved with highly conformal techniques (IMRT and HT) without compromising the PTV conformity and homogeneity. PMID:26865754

  14. Synchronous bilateral squamous cell carcinoma of the lung successfully treated using intensity-modulated radiotherapy

    PubMed Central

    Loo, S W; Smith, S; Promnitz, D A; Van Tornout, F

    2012-01-01

    We present a case of synchronous bilateral inoperable lung cancer which required treatment with external beam radiotherapy to a radical dose. Intensity-modulated radiotherapy (IMRT) was used. More conformal dose distribution within the planning target volume was obtained using IMRT than the conventional technique. Dose–volume constraints defined for the lungs were met. Treatment was subsequently delivered using a seven-field IMRT plan. The patient remains alive and disease-free 48 months after the completion of radiotherapy. IMRT can be considered an effective treatment for synchronous bilateral lung cancer. PMID:21937610

  15. Clinical Experience With Image-Guided Radiotherapy in an Accelerated Partial Breast Intensity-Modulated Radiotherapy Protocol

    SciTech Connect

    Leonard, Charles E.; Tallhamer, Michael M.S.; Johnson, Tim; Hunter, Kari C.M.D.; Howell, Kathryn; Kercher, Jane; Widener, Jodi; Kaske, Terese; Paul, Devchand; Sedlacek, Scot; Carter, Dennis L.

    2010-02-01

    Purpose: To explore the feasibility of fiducial markers for the use of image-guided radiotherapy (IGRT) in an accelerated partial breast intensity modulated radiotherapy protocol. Methods and Materials: Nineteen patients consented to an institutional review board approved protocol of accelerated partial breast intensity-modulated radiotherapy with fiducial marker placement and treatment with IGRT. Patients (1 patient with bilateral breast cancer; 20 total breasts) underwent ultrasound guided implantation of three 1.2- x 3-mm gold markers placed around the surgical cavity. For each patient, table shifts (inferior/superior, right/left lateral, and anterior/posterior) and minimum, maximum, mean error with standard deviation were recorded for each of the 10 BID treatments. The dose contribution of daily orthogonal films was also examined. Results: All IGRT patients underwent successful marker placement. In all, 200 IGRT treatment sessions were performed. The average vector displacement was 4 mm (range, 2-7 mm). The average superior/inferior shift was 2 mm (range, 0-5 mm), the average lateral shift was 2 mm (range, 1-4 mm), and the average anterior/posterior shift was 3 mm (range, 1 5 mm). Conclusions: This study shows that the use of IGRT can be successfully used in an accelerated partial breast intensity-modulated radiotherapy protocol. The authors believe that this technique has increased daily treatment accuracy and permitted reduction in the margin added to the clinical target volume to form the planning target volume.

  16. Long-Term Breast Cancer Patient Outcomes After Adjuvant Radiotherapy Using Intensity-Modulated Radiotherapy or Conventional Tangential Radiotherapy

    PubMed Central

    Yang, Jen-Fu; Lee, Meei-Shyuan; Lin, Chun-Shu; Chao, Hsing-Lung; Chen, Chang-Ming; Lo, Cheng-Hsiang; Fan, Chao-Yueh; Tsao, Chih-Cheng; Huang, Wen-Yen

    2016-01-01

    Abstract The aim of the article is to analyze breast cancer patient clinical outcomes after long-term follow-up using intensity-modulated radiotherapy (IMRT) or conventional tangential radiotherapy (cRT). We retrospectively reviewed patients with stage 0–III breast cancer who received breast conserving therapy between April 2004 and December 2007. Of the 234 patients, 103 (44%) were treated with IMRT and 131 (56%) were treated with cRT. A total prescription dose of 45 to 50 Gy (1.8–2 Gy per fraction) was delivered to the whole breast. A 14 Gy boost dose was delivered in 7 fractions. The median follow-up was 8.2 years. Five of 131 (3.8%) cRT-treated patients and 2 of 103 (1.9%) IMRT-treated patients had loco-regional failure. The 8-year loco-regional failure-free survival rates were 96.7% and 97.6% (P = 0.393) in the cRT and IMRT groups, respectively, whereas the 8-year disease-free survival (DFS) rates were 91.2% and 93.1%, respectively (P = 0.243). Patients treated with IMRT developed ≥ grade 2 acute dermatitis less frequently than patients treated with cRT (40.8% vs 56.5%; P = 0.017). There were no differences in late toxicity. IMRT reduces ≥ grade 2 acute skin toxicity. Local control, DFS, and overall survival were equivalent with IMRT and cRT. IMRT can be considered a standard technique for breast cancer treatment. PMID:26986158

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

    SciTech Connect

    Holt, Andrea; Vliet-Vroegindeweij, Corine van; Mans, Anton; Belderbos, Jose S.; Damen, Eugene M.F.

    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.

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

    PubMed Central

    Murray, Julia R; McNair, Helen A; Dearnaley, David P

    2015-01-01

    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. PMID:26635484

  19. Clinical evaluation of intensity-modulated radiotherapy for head and neck cancers

    PubMed Central

    Bhide, S A; Newbold, K L; Harrington, K J; Nutting, C M

    2012-01-01

    Radiotherapy and surgery are the principal curative modalities in treatment of head and neck cancer. Conventional two-dimensional and three-dimensional conformal radiotherapy result in significant side effects and altered quality of life. Intensity-modulated radiotherapy (IMRT) can spare the normal tissues, while delivering a curative dose to the tumour-bearing tissues. This article reviews the current role of IMRT in head and neck cancer from the point of view of normal tissue sparing, and also reviews the current published literature by individual head and neck cancer subsites. In addition, we briefly discuss the role of image guidance in head and neck IMRT, and future directions in this area. PMID:22556403

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

    PubMed Central

    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

  1. Intensity-Modulated Radiotherapy for Cervical Lymph Node Metastases From Unknown Primary Cancer

    SciTech Connect

    Madani, Indira Vakaet, Luc; Bonte, Katrien; Boterberg, Tom; Neve, Wilfried de

    2008-07-15

    Purpose: To compare the effectiveness of intensity-modulated radiotherapy (IMRT) and conventional (two-dimensional) radiotherapy in the treatment of cervical lymph node metastases from unknown primary cancer (UPC). Methods and Materials: Between February 2003 and September 2006, 23 patients with UPC of squamous cell carcinoma were treated with IMRT. Extended putative mucosal and bilateral nodal sites were irradiated to a median dose of 66 Gy. In 19 patients, IMRT was performed after lymph node dissection, and in 4 patients primary radiotherapy was given. The conventional radiotherapy group (historical control group) comprised 18 patients treated to a median dose of 66 Gy between August 1994 and October 2003. Results: Twenty patients completed treatment. As compared with conventional radiotherapy, the incidence of Grade 3 acute dysphagia was significantly lower in the IMRT group (4.5% vs. 50%, p = 0.003). By 6 months, Grade 3 xerostomia was detected in 11.8% patients in the IMRT group vs. 53.4% in the historical control group (p = 0.03). No Grade 3 dysphagia or skin fibrosis was observed after IMRT but these were noted after conventional radiotherapy (26.7%, p = 0.01) and 26.7%, p = 0.03) respectively). With median follow-up of living patients of 17 months, there was no emergence of primary cancer. One patient had persistent nodal disease and another had nodal relapse at 5 months. Distant metastases were detected in 4 patients. The 2-year overall survival and distant disease-free probability after IMRT did not differ significantly from those for conventional radiotherapy (74.8% vs. 61.1% and 76.3% vs. 68.4%, respectively). Conclusions: Use of IMRT for UPC resulted in lower toxicity than conventional radiotherapy, and was similar in efficacy.

  2. Large Cohort Dose-Volume Response Analysis of Parotid Gland Function After Radiotherapy: Intensity-Modulated Versus Conventional Radiotherapy

    SciTech Connect

    Dijkema, Tim Terhaard, Chris H.J.; Roesink, Judith M.; Braam, Petra M.; Gils, Carla H. van; Moerland, Marinus A.; Raaijmakers, Cornelis P.J.

    2008-11-15

    Purpose: To compare parotid gland dose-volume response relationships in a large cohort of patients treated with intensity-modulated (IMRT) and conventional radiotherapy (CRT). Methods and materials: A total of 221 patients (64 treated with IMRT, 157 with CRT) with various head-and-neck malignancies were prospectively evaluated. The distribution of tumor subsites in both groups was unbalanced. Stimulated parotid flow rates were measured before and 6 weeks, 6 months, and 1 year after radiotherapy. Parotid gland dose-volume histograms were derived from computed tomography-based treatment planning. The normal tissue complication probability (NTCP) model proposed by Lyman was fit to the data. A complication was defined as stimulated parotid flow ratio <25% of the pretreatment flow rate. The relative risk of complications was determined for IMRT vs. CRT and adjusted for the mean parotid gland dose using Poisson regression modeling. Results: One year after radiotherapy, NTCP curves for IMRT and CRT were comparable with a TD{sub 50} (uniform dose leading to a 50% complication probability) of 38 and 40 Gy, respectively. Until 6 months after RT, corrected for mean dose, different complication probabilities existed for IMRT vs. CRT. The relative risk of a complication for IMRT vs. CRT after 6 weeks was 1.42 (95% CI 1.21-1.67), after 6 months 1.41 (95% CI; 1.12-1.77), and at 1 year 1.21 (95% CI 0.87-1.68), after correcting for mean dose. Conclusions: One year after radiotherapy, no difference existed in the mean dose-based NTCP curves for IMRT and CRT. Early after radiotherapy (up to 6 months) mean dose based (Lyman) models failed to fully describe the effects of radiotherapy on the parotid glands.

  3. Volumetric Modulation Arc Radiotherapy Compared With Static Gantry Intensity-Modulated Radiotherapy for Malignant Pleural Mesothelioma Tumor: A Feasibility Study

    SciTech Connect

    Scorsetti, Marta; Bignardi, Mario; Clivio, Alessandro

    2010-07-01

    Purpose: A planning study was performed to evaluate RapidArc (RA), a volumetric modulated arc technique, on malignant pleural mesothelioma. The benchmark was conventional fixed-field intensity-modulated radiotherapy (IMRT). Methods and materials: The computed tomography data sets of 6 patients were included. The plans for IMRT with nine fixed beams were compared against double-modulated arcs with a single isocenter. All plans were optimized for 15-MV photon beams. The dose prescription was 54 Gy to the planning target volume. The planning objectives for the planning target volume were a minimal dose of >95% and maximal dose of <107%. For the organs at risk, the parameters were as follows: contralateral lung, percentage of volume receiving 5 Gy (V{sub 5Gy}) <60%, V{sub 20Gy} < 10%, mean <10.0 Gy; liver, V{sub 30Gy} <33%, mean <31 Gy; heart, V{sub 45Gy} <30%, V{sub 50Gy} <20%, dose received by 1% of the volume (D{sub 1%}) <60 Gy; contralateral kidney, V{sub 15Gy} <20%; spine, D{sub 1%} <45 Gy; esophagus, V{sub 55Gy} <30%; and spleen, V{sub 40Gy} <50%. The monitor units (MUs) and delivery time were scored to measure the treatment efficiency. The pretreatment portal dosimetry scored delivery to the calculation agreement with the Gamma Agreement Index. Results: RA and IMRT provided equivalent coverage and homogeneity. Both techniques fulfilled objectives on organs at risk with a tendency of RA to improve sparing. The conformity index was 1.9 {+-} 0.1 for RA and IMRT. The number of MU/2Gy was 734 {+-} 82 for RA and 2,195 {+-} 317 for IMRT. The planning vs. delivery agreement revealed a Gamma Agreement Index for IMRT of 96.0% {+-} 2.6% and for RA of 95.7% {+-} 1.5%. The treatment time was 3.7 {+-} 0.3min for RA and 13.4 {+-} 0.1min for IMRT. Conclusion: RA demonstrated compared with conventional IMRT, similar target coverage and better dose sparing to the organs at risks. The number of MUs and the time required to deliver a 2-Gy fraction were much lower for RA, allowing

  4. A Comparison of Helical Intensity-Modulated Radiotherapy, Intensity-Modulated Radiotherapy, and 3D-Conformal Radiation Therapy for Pancreatic Cancer

    SciTech Connect

    Poppe, Matthew M.; Narra, Venkat; Yue, Ning J.; Zhou Jinghao; Nelson, Carl; Jabbour, Salma K.

    2011-01-01

    We assessed dosimetric differences in pancreatic cancer radiotherapy via helical intensity-modulated radiotherapy (HIMRT), linac-based IMRT, and 3D-conformal radiation therapy (3D-CRT) with regard to successful plan acceptance and dose to critical organs. Dosimetric analysis was performed in 16 pancreatic cases that were planned to 54 Gy; both post-pancreaticoduodenectomy (n = 8) and unresected (n = 8) cases were compared. Without volume modification, plans met constraints 75% of the time with HIMRT and IMRT and 13% with 3D-CRT. There was no statistically significantly improvement with HIMRT over conventional IMRT in reducing liver V35, stomach V45, or bowel V45. HIMRT offers improved planning target volume (PTV) dose homogeneity compared with IMRT, averaging a lower maximum dose and higher volume receiving the prescription dose (D100). HIMRT showed an increased mean dose over IMRT to bowel and liver. Both HIMRT and IMRT offer a statistically significant improvement over 3D-CRT in lowering dose to liver, stomach, and bowel. The results were similar for both unresected and resected patients. In pancreatic cancer, HIMRT offers improved dose homogeneity over conventional IMRT and several significant benefits to 3D-CRT. Factors to consider before incorporating IMRT into pancreatic cancer therapy are respiratory motion, dose inhomogeneity, and mean dose.

  5. Volumetric Arc Intensity-Modulated Therapy for Spine Body Radiotherapy: Comparison With Static Intensity-Modulated Treatment

    SciTech Connect

    Wu, Q. Jackie; Yoo, Sua; Kirkpatrick, John P.; Thongphiew, Danthai; Yin Fangfang

    2009-12-01

    Purpose: This clinical study evaluates the feasibility of using volumetric arc-modulated treatment (VMAT) for spine stereotactic body radiotherapy (SBRT) to achieve highly conformal dose distributions that spare adjacent organs at risk (OAR) with reduced treatment time. Methods and Materials: Ten spine SBRT patients were studied retrospectively. The intensity-modulated radiotherapy (IMRT) and VMAT plans were generated using either one or two arcs. Planning target volume (PTV) dose coverage, OAR dose sparing, and normal tissue integral dose were measured and compared. Differences in treatment delivery were also analyzed. Results: The PTV DVHs were comparable between VMAT and IMRT plans in the shoulder (D{sub 99%}-D{sub 90%}), slope (D{sub 90%}-D{sub 10%}), and tail (D{sub 10%}-D{sub 1%}) regions. Only VMAT{sub 2arc} had a better conformity index than IMRT (1.09 vs. 1.15, p = 0.007). For cord sparing, IMRT was the best, and VMAT{sub 1arc} was the worst. Use of IMRT achieved greater than 10% more D{sub 1%} sparing for six of 10 cases and 7% to 15% more D{sub 10%} sparing over the VAMT{sub 1arc}. The differences between IMRT and VAMT{sub 2arc} were smaller and statistically nonsignificant at all dose levels. The differences were also small and statistically nonsignificant for other OAR sparing. The mean monitor units (MUs) were 8711, 7730, and 6317 for IMRT, VMAT{sub 1arc}, and VMAT{sub 2arc} plans, respectively, with a 26% reduction from IMRT to VMAT{sub 2arc}. The mean treatment time was 15.86, 8.56, and 7.88 min for IMRT, VMAT{sub 1arc,} and VMAT{sub 2arc}. The difference in integral dose was statistically nonsignificant. Conclusions: Although VMAT provided comparable PTV coverage for spine SBRT, 1arc showed significantly worse spinal cord sparing compared with IMRT, whereas 2arc was comparable to IMRT. Treatment efficiency is substantially improved with the VMAT.

  6. SU-E-T-234: Modulated Photon Radiotherapy (XMRT):The Impact of Incorporating Energy Modulation Into Intensity Modulated Radiotherapy (IMRT) Optimization

    SciTech Connect

    McGeachy, P; Khan, R

    2014-06-01

    Purpose: To develop a new radiotherapy plan optimization technique that, for a given organ geometry, will find the optimal photon beam energies and fluences to produce a desirable dose distribution. This new modulated (both in energy and fluence) photon radiotherapy (XMRT) was compared with intensity modulated radiotherapy (IMRT) for a simple organ geometry. Methods: The XMRT optimization was formulated using a linear programming approach where the objective function is the mean dose to the healthy organs and dose-point constraints were assigned to each organ of interest. The organ geometry consisted of a target, two organs at risk (OARs), and normal tissue. A seven-equispaced-coplanar beam arrangement was used. For conventional IMRT, only 6 MV beams were available, while XMRT was optimized using 6 and 18 MV beams. A prescribed dose (PD) of 72 GY was assigned to the target, with upper and lower bounds of 110% and 95% of the PD, respectively. Both OARs were assigned a maximum dose of 64 Gy, while the normal tissue was assigned a maximum dose of 66 Gy. A numerical solver, Gurobi, generated solutions for the XMRT and IMRT problems. The dose-volume histograms from IMRT and XMRT solutions were compared. Results: The maximum, minimum, mean, and homogeneity of the dose to the target were comparable between IMRT and XMRT. Though IMRT had improved dose conformity relative to XMRT, XMRT reduced the mean dose to both OARs by more than 1 Gy. For normal tissue, an increase of 5 Gy in mean dose and 27 percent in integral dose was seen for IMRT relative to XMRT. Conclusion: This work demonstrates the benefits of simultaneously modulating photon beam energy and fluence using our XMRT approach in a given phantom geometry. While target coverage was comparable, dose to healthy structures was reduced using XMRT.

  7. Whole Pelvic Intensity-modulated Radiotherapy for Gynecological Malignancies: A Review of the Literature

    PubMed Central

    Hymel, Rockne; Jones, Guy C.; Simone, Charles B.

    2015-01-01

    Radiation therapy has long played a major role in the treatment of gynecological malignancies. There is increasing interest in the utility of intensity-modulated radiotherapy (IMRT) and its application to treat gynecological malignancies. Herein, we review the state-of-the-art use of IMRT for gynecological malignancies and report how it is being used alone as well as in combination with chemotherapy in both the adjuvant and definitive settings. Based on dosimetric and clinical evidence, IMRT can reduce gastrointestinal, genitourinary, and hematological toxicities compared with 3D conformal radiotherapy for gynecologic malignancies. We discuss how these attributes of IMRT may lead to improvements in disease outcomes by allowing for dose escalation of radiation therapy, intensification of chemotherapy, and limiting toxicity-related treatment breaks. Currently accruing trials investigating pelvic IMRT for cervical and endometrial cancers are discussed. PMID:25600840

  8. Stereotactic Image-Guided Intensity Modulated Radiotherapy Using the HI-ART II Helical Tomotherapy System

    SciTech Connect

    Holmes, Timothy W. Hudes, Richard; Dziuba, Sylwester; Kazi, Abdul; Hall, Mark; Dawson, Dana

    2008-07-01

    The highly integrated adaptive radiation therapy (HI-ART II) helical tomotherapy unit is a new radiotherapy machine designed to achieve highly precise and accurate treatments at all body sites. The precision and accuracy of the HI-ART II is similar to that provided by stereotactic radiosurgery systems, hence the historical distinction between external beam radiotherapy and stereotactic procedures based on differing precision requirements is removed for this device. The objectives of this work are: (1) to describe stereotactic helical tomotherapy processes (SRS, SBRT); (2) to show that the precision and accuracy of the HI-ART meet the requirements defined for SRS and SBRT; and (3) to describe the clinical implementation of a stereotactic image-guided intensity modulated radiation therapy (IG-IMRT) system that incorporates optical motion management.

  9. The use of intensity modulated radiotherapy for the treatment of extensive and recurrent juvenile angiofibroma.

    PubMed

    Kuppersmith, R B; Teh, B S; Donovan, D T; Mai, W Y; Chiu, J K; Woo, S Y; Butler, E B

    2000-05-30

    These case series are presented to describe the application and advantages of intensity modulated radiotherapy (IMRT) for the treatment of extensive and/or recurrent juvenile angiofibroma. Two patients were diagnosed with recurrence at 11 and 13 months postoperatively, and one was surgically unresectable. The affected areas included the base of skull, cavernous sinus, pterygopalatine fossa, infratemporal fossa, posterior orbit and nasopharynx. Highly conformal IMRT was delivered with limited radiation doses to the optic nerves, optic chiasm, brainstem, brain, spinal cord, lens, retina, mandible, and parotid. The total dose delivered to the tumor varied from 3400 to 4500 cGy. The tumor shrunk radiographically in all three cases and there was no endoscopic evidence of disease in two cases at 15 months and 40 months. There was no acute toxicity. Late toxicity was limited to one episode of epistaxis and persistent rhinitis in one patient. In conclusion, IMRT provides several advantages over conventional radiotherapy in the treatment of recurrent juvenile angiofibroma.

  10. Predictors for Clinical Outcomes After Accelerated Partial Breast Intensity-Modulated Radiotherapy

    SciTech Connect

    Reeder, Reed; Carter, Dennis L. Howell, Kathryn; Henkenberns, Phyllis; Tallhamer, Michael; Johnson, Tim; Kercher, Jane; Widner, Jodi; Kaske, Terese; Paul, Devchand; Sedlacek, Scot; Leonard, Charles E.

    2009-05-01

    Purpose: To correlate the treatment planning parameters with the clinical outcomes in patients treated with accelerated partial breast intensity-modulated radiotherapy. Methods and Materials: A total of 105 patients with Stage I breast cancer were treated between February 2004 and March 2007 in a Phase II prospective trial and had detailed information available on the planning target volume (PTV), ipsilateral breast volume (IBV), PTV/IBV ratio, lung volume, chest wall volume, surgery to radiotherapy interval, follow-up interval, breast pain, and cosmesis. The first 7 of these patients were treated to 34 Gy, and the remaining 98 were treated to 38.5 Gy. All patients were treated twice daily for 5 consecutive days. Univariate and multivariate analyses were performed. Results: The median follow-up was 13 months. No recurrences or deaths were observed. Of the 105 patients, 30 reported mild or moderate breast pain in their most recently recorded follow-up visit. The irradiated lung volume (p < 0.05) and chest wall volume receiving >35 Gy (p < 0.01) were associated with pain. The PTV, but not the PTV/IBV ratio, also correlated with pain (p < 0.01 and p = 0.42, respectively). A total of 72 patients reported excellent, 32 reported good, and 1 reported poor cosmesis. Physician-rated cosmesis reported 90 excellent and 15 good. None of the tested variables correlated with the cosmetic outcomes. Conclusion: Radiotherapy to the chest wall (chest wall volume receiving >35 Gy) and to lung correlated with reports of mild pain after accelerated partial breast intensity-modulated radiotherapy. Also, the PTV, but not the PTV/IBV ratio, was predictive of post-treatment reports of pain.

  11. Volumetric-modulated arc radiotherapy for pancreatic malignancies: Dosimetric comparison with sliding-window intensity-modulated radiotherapy and 3-dimensional conformal radiotherapy

    SciTech Connect

    Nabavizadeh, Nima Simeonova, Anna O.; Waller, Joseph G.; Romer, Jeanna L.; Monaco, Debra L.; Elliott, David A.; Tanyi, James A.; Fuss, Martin; Thomas, Charles R.; Holland, John M.

    2014-10-01

    Volumetric-modulated arc radiotherapy (VMAT) is an iteration of intensity-modulated radiotherapy (IMRT), both of which deliver highly conformal dose distributions. Studies have shown the superiority of VMAT and IMRT in comparison with 3-dimensional conformal radiotherapy (3D-CRT) in planning target volume (PTV) coverage and organs-at-risk (OARs) sparing. This is the first study examining the benefits of VMAT in pancreatic cancer for doses more than 55.8 Gy. A planning study comparing 3D-CRT, IMRT, and VMAT was performed in 20 patients with pancreatic cancer. Treatments were planned for a 25-fraction delivery of 45 Gy to a large field followed by a reduced-volume 8-fraction external beam boost to 59.4 Gy in total. OARs and PTV doses, conformality index (CI) deviations from 1.0, monitor units (MUs) delivered, and isodose volumes were compared. IMRT and VMAT CI deviations from 1.0 for the large-field and the boost plans were equivalent (large field: 0.032 and 0.046, respectively; boost: 0.042 and 0.037, respectively; p > 0.05 for all comparisons). Both IMRT and VMAT CI deviations from 1.0 were statistically superior to 3D-CRT (large field: 0.217, boost: 0.177; p < 0.05 for all comparisons). VMAT showed reduction of the mean dose to the boost PTV (VMAT: 61.4 Gy, IMRT: 62.4 Gy, and 3D-CRT: 62.3 Gy; p < 0.05). The mean number of MUs per fraction was significantly lower for VMAT for both the large-field and the boost plans. VMAT delivery time was less than 3 minutes compared with 8 minutes for IMRT. Although no statistically significant dose reduction to the OARs was identified when comparing VMAT with IMRT, VMAT showed a reduction in the volumes of the 100% isodose line for the large-field plans. Dose escalation to 59.4 Gy in pancreatic cancer is dosimetrically feasible with shorter treatment times, fewer MUs delivered, and comparable CIs for VMAT when compared with IMRT.

  12. Dosimetric Comparison of Three-Dimensional Conformal Proton Radiotherapy, Intensity-Modulated Proton Therapy, and Intensity-Modulated Radiotherapy for Treatment of Pediatric Craniopharyngiomas

    SciTech Connect

    Boehling, Nicholas S.; Grosshans, David R.; Bluett, Jaques B.; Palmer, Matthew T.; Song, Xiaofei; Amos, Richard A.; Sahoo, Narayan; Meyer, Jeffrey J.; Mahajan, Anita; Woo, Shiao Y.

    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

  13. Retrospective evaluation of dosimetric quality for prostate carcinomas treated with 3D conformal, intensity modulated and volumetric modulated arc radiotherapy

    SciTech Connect

    Crowe, Scott B; Kairn, Tanya; Middlebrook, Nigel; Hill, Brendan; Christie, David R H; Knight, Richard T; Kenny, John; Langton, Christian M; Trapp, Jamie V

    2013-12-15

    This study examines and compares the dosimetric quality of radiotherapy treatment plans for prostate carcinoma across a cohort of 163 patients treated across five centres: 83 treated with three-dimensional conformal radiotherapy (3DCRT), 33 treated with intensity modulated radiotherapy (IMRT) and 47 treated with volumetric modulated arc therapy (VMAT). Treatment plan quality was evaluated in terms of target dose homogeneity and organs at risk (OAR), through the use of a set of dose metrics. These included the mean, maximum and minimum doses; the homogeneity and conformity indices for the target volumes; and a selection of dose coverage values that were relevant to each OAR. Statistical significance was evaluated using two-tailed Welch's T-tests. The Monte Carlo DICOM ToolKit software was adapted to permit the evaluation of dose metrics from DICOM data exported from a commercial radiotherapy treatment planning system. The 3DCRT treatment plans offered greater planning target volume dose homogeneity than the other two treatment modalities. The IMRT and VMAT plans offered greater dose reduction in the OAR: with increased compliance with recommended OAR dose constraints, compared to conventional 3DCRT treatments. When compared to each other, IMRT and VMAT did not provide significantly different treatment plan quality for like-sized tumour volumes. This study indicates that IMRT and VMAT have provided similar dosimetric quality, which is superior to the dosimetric quality achieved with 3DCRT.

  14. Assessment and Minimization of Contralateral Breast Dose for Conventional and Intensity Modulated Breast Radiotherapy

    SciTech Connect

    Burmeister, Jay Alvarado, Nicole; Way, Sarah; McDermott, Patrick; Bossenberger, Todd; Jaenisch, Harriett; Patel, Rajiv; Washington, Tara

    2008-04-01

    Breast radiotherapy is associated with an increased risk of contralateral breast cancer (CBC) in women under age 45 at the time of treatment. This risk increases with increasing absorbed dose to the contralateral breast. The use of intensity modulated radiotherapy (IMRT) is expected to substantially reduce the dose to the contralateral breast by eliminating scattered radiation from physical beam modifiers. The absorbed dose to the contralateral breast was measured for 5 common radiotherapy techniques, including paired 15 deg. wedges, lateral 30 deg. wedge only, custom-designed physical compensators, aperture based (field-within-field) IMRT with segments chosen by the planner, and inverse planned IMRT with segments chosen by a leaf sequencing algorithm after dose volume histogram (DVH)-based fluence map optimization. Further reduction in contralateral breast dose through the use of lead shielding was also investigated. While shielding was observed to have the most profound impact on surface dose, the radiotherapy technique proved to be most important in determining internal dose. Paired wedges or compensators result in the highest contralateral breast doses (nearly 10% of the prescription dose on the medial surface), while use of IMRT or removal of the medial wedge results in significantly lower doses. Aperture-based IMRT results in the lowest internal doses, primarily due to the decrease in the number of monitor units required and the associated reduction in leakage dose. The use of aperture-based IMRT reduced the average dose to the contralateral breast by greater than 50% in comparison to wedges or compensators. Combined use of IMRT and 1/8-inch-thick lead shielding reduced the dose to the interior and surface of the contralateral breast by roughly 60% and 85%, respectively. This reduction may warrant the use of IMRT for younger patients who have a statistically significant risk of contralateral breast cancer associated with breast radiotherapy.

  15. Clinical Outcomes and Patterns of Failure After Intensity-Modulated Radiotherapy for Nasopharyngeal Carcinoma

    SciTech Connect

    Ng, Wai Tong; Lee, Michael C.H.; Hung, Wai Man; Choi, Cheuk Wai; Lee, Kin Chung; Chan, Oscar S.H.; Lee, Anne W.M.

    2011-02-01

    Purpose: To study and report the clinical outcomes and patterns of failure after intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC). Methods and Materials: The treatment outcomes of NPC patients treated with IMRT at Pamela Youde Nethersole Eastern Hospital between 2005 and 2007 were reviewed. The location and extent of locoregional failures were transferred to the pretreatment planning computed tomography for dosimetry analysis. Statistical analyses were performed on dose coverage and locoregional failures. Results: A total of 193 NPC patients were analyzed; 93% had Stage III/IV disease. Median follow-up was 30 months. Overall disease failure (at any site) developed in 35 patients. Among these, there were 23 distant metastases, 16 local failures, and 9 regional failures. Four of the locoregional failures were marginal. Dose conformity with IMRT was excellent. Patients with at least 66.5 Gy to their target volumes had significantly less locoregional failure. The 2-year local progression-free, regional progression-free, distant metastasis-free, and overall survival rates were 95%, 96%, 90%, and 92%, respectively. Conclusions: Intensity-modulated radiotherapy provides excellent locoregional control for NPC. Distant metastasis remains the most difficult challenge, and more effective systemic agents should be explored for patients presenting with advanced locoregional diseases.

  16. Intensity-modulated stereotactic radiotherapy (IMSRT) for skull-base meningiomas

    SciTech Connect

    Yenice, Kamil M. . E-mail: kyenice@radonc.uchicago.edu; Narayana, Ashwatha; Chang, Jenghwa; Gutin, Philip H.; Amols, Howard I.

    2006-11-15

    Purpose: To investigate the potential benefits of a micromultileaf collimator ({mu}MLC) -based intensity-modulated stereotactic radiotherapy (IMSRT) in skull-base meningiomas. Methods and Materials: Seven patients with inoperable or recurrent small-volume (1.7-15.5 cc) skull-base meningiomas were treated with IMSRT to 54 Gy in 30 fractions using a {mu}MLC in the dynamic mode. IMSRT plan quality was evaluated in comparison with the conformal stereotactic radiotherapy technique, using the same beam arrangement and static delivery with the {mu}MLC. Plans were compared using multiple dose distributions and dose-volume histograms for the planning target volume and organs at risk. The conformity and uniformity metrics, as well as normal-tissue complication probabilities, were calculated for the two techniques. Follow-up with MRI and clinical examination was performed at regular intervals. Results: With a mean follow-up of 17 months, local control has been achieved in all cases, and no treatment-related toxicities have been noted. For cavernous sinus tumors overlapping with optic apparatus, IMSRT has improved the dose uniformity within the target on average by 8%, which resulted in a reduction of the estimated chiasm normal-tissue complication probability by up to 65%. Conclusions: Intensity-modulated stereotactic radiotherapy can be safely delivered to improve the dose distributions in select skull-base meningiomas with an appreciable concomitant dose reduction to involved critical structures. Longer follow-up with a larger patient group is necessary to demonstrate sustained tumor control and low morbidity with IMSRT for small inoperable, recurrent, or subtotally resected meningiomas.

  17. Risk of second malignant neoplasm following proton versus intensity-modulated photon radiotherapies for hepatocellular carcinoma

    NASA Astrophysics Data System (ADS)

    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.

  18. Risk of second malignant neoplasm following proton versus intensity-modulated photon radiotherapies for hepatocellular carcinoma.

    PubMed

    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.

  19. Volumetric Modulated Arc Therapy for Delivery of Prostate Radiotherapy: Comparison With Intensity-Modulated Radiotherapy and Three-Dimensional Conformal Radiotherapy

    SciTech Connect

    Palma, David Vollans, Emily; James, Kerry; Nakano, Sandy; Moiseenko, Vitali; Shaffer, Richard; McKenzie, Michael; Morris, James; Otto, Karl

    2008-11-15

    Purpose: Volumetric modulated arc therapy (VMAT) is a novel form of intensity-modulated radiotherapy (IMRT) optimization that allows the radiation dose to be delivered in a single gantry rotation of up to 360{sup o}, using either a constant dose rate (cdr-VMAT) or variable dose rate (vdr-VMAT) during rotation. The goal of this study was to compare VMAT prostate RT plans with three-dimensional conformal RT (3D-CRT) and IMRT plans. Patients and Methods: The 3D-CRT, five-field IMRT, cdr-VMAT, and vdr-VMAT RT plans were created for 10 computed tomography data sets from patients undergoing RT for prostate cancer. The parameters evaluated included the doses to organs at risk, equivalent uniform doses, dose homogeneity and conformality, and monitor units required for delivery of a 2-Gy fraction. Results: The IMRT and both VMAT techniques resulted in lower doses to normal critical structures than 3D-CRT plans for nearly all dosimetric endpoints analyzed. The lowest doses to organs at risk and most favorable equivalent uniform doses were achieved with vdr-VMAT, which was significantly better than IMRT for the rectal and femoral head dosimetric endpoints (p < 0.05) and significantly better than cdr-VMAT for most bladder and rectal endpoints (p < 0.05). The vdr-VMAT and cdr-VMAT plans required fewer monitor units than did the IMRT plans (relative reduction of 42% and 38%, respectively; p = 0.005) but more than for the 3D-CRT plans (p = 0.005). Conclusion: The IMRT and VMAT techniques achieved highly conformal treatment plans. The vdr-VMAT technique resulted in more favorable dose distributions than the IMRT or cdr-VMAT techniques, and reduced the monitor units required compared with IMRT.

  20. Value of Intensity-Modulated Radiotherapy in Stage IV Head-and-Neck Squamous Cell Carcinoma

    SciTech Connect

    Dirix, Piet; Nuyts, Sandra

    2010-12-01

    Purpose: To review outcome and toxicity of Stage IVa and IVb head-and-neck squamous cell carcinoma patients treated with concomitant chemotherapy and intensity-modulated radiotherapy (IMRT) according to a hybrid fractionation schedule. Methods and Materials: Between 2006 and 2008, 42 patients with Stage IV head-and-neck squamous cell carcinoma were irradiated according to a hybrid fractionation schedule consisting of 20 fractions of 2 Gy (once daily), followed by 20 fractions of 1.6 Gy (twice daily), to a total dose of 72 Gy. Chemotherapy (cisplatinum, 100mg/m{sup 2}) was administered at the start of Weeks 1 and 4. Treatment outcome and toxicity were retrospectively compared with a previous patient group (n = 55), treated according to the same schedule, but without intensity modulation. Results: Locoregional control (LRC) and overall survival were 81% and 56% after 2 years, respectively. In comparison with the previous cohort, no significant differences were observed regarding either LRC (66%, p = 0.38) or overall survival (73%, p = 0.29). No Grade 4 or 5 toxicity was reported in the IMRT group, either acute or chronic. The use of IMRT significantly reduced the incidence of late Grade 2 or 3 xerostomia (52.9% vs. 90.2%, p < 0.001). No difference was observed regarding late Grade 2 or 3 dysphagia (p = 0.66). Conclusions: Intensity-modulated chemoradiotherapy does not compromise LRC and significantly reduces late toxicity, especially regarding xerostomia.

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

    PubMed Central

    Ming, Xin; Feng, Yuanming; Liu, Huan; Zhang, Ying; Zhou, Li; Deng, Jun

    2015-01-01

    Purpose 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. Methods and Materials 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. Results 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. Conclusions 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. PMID:26630566

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

    PubMed Central

    Kang, Hye Jin; Son, Seok Hyun; Kim, Myungsoo; Jo, In Young; Lee, So Jung; Lee, Dong Hwan; Suh, Hong Jin; Choi, Yong Sun

    2016-01-01

    Purpose The aim of this work was to assess the efficacy and tolerability of hypofractionated intensity-modulated radiotherapy (IMRT) in patients with localized prostate cancer. Materials and Methods 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. Results 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. Conclusion 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. PMID:27104166

  3. Dose to Larynx Predicts for Swallowing Complications After Intensity-Modulated Radiotherapy

    SciTech Connect

    Caglar, Hale B.; Tishler, Roy B.; Burke, Elaine; Li Yi; Goguen, Laura; Norris, Carl M.; Allen, Aaron M.

    2008-11-15

    Purpose: To evaluate early swallowing after intensity-modulated radiotherapy for head and neck squamous cell carcinoma and determine factors correlating with aspiration and/or stricture. Methods and Materials: Consecutive patients treated with intensity-modulated radiotherapy with or without chemotherapy between September 2004 and August 2006 at the Dana Farber Cancer Institute/Brigham and Women's Hospital were evaluated with institutional review board approval. Patients underwent swallowing evaluation after completion of therapy; including video swallow studies. The clinical- and treatment-related variables were examined for correlation with aspiration or strictures, as well as doses to the larynx, pharyngeal constrictor muscles, and cervical esophagus. The correlation was assessed with logistic regression analysis. Results: A total of 96 patients were evaluated. Their median age was 55 years, and 79 (82%) were men. The primary site of cancer was the oropharynx in 43, hypopharynx/larynx in 17, oral cavity in 13, nasopharynx in 11, maxillary sinus in 2, and unknown primary in 10. Of the 96 patients, 85% underwent definitive RT and 15% postoperative RT. Also, 28 patients underwent induction chemotherapy followed by concurrent chemotherapy, 59 received concurrent chemotherapy, and 9 patients underwent RT alone. The median follow-up was 10 months. Of the 96 patients, 31 (32%) had clinically significant aspiration and 36 (37%) developed a stricture. The radiation dose-volume metrics, including the volume of the larynx receiving {>=}50 Gy (p = 0.04 and p = 0.03, respectively) and volume of the inferior constrictor receiving {>=}50 Gy (p = 0.05 and p = 0.02, respectively) were significantly associated with both aspiration and stricture. The mean larynx dose correlated with aspiration (p = 0.003). Smoking history was the only clinical factor to correlate with stricture (p = 0.05) but not aspiration. Conclusion: Aspiration and stricture are common side effects after

  4. Intensity-modulated radiotherapy, not 3D conformal, is the preferred technique for treating locally advanced lung cancer

    PubMed Central

    Chang, Joe Y.

    2015-01-01

    When used to treat lung cancer, intensity-modulated radiotherapy (IMRT) can deliver higher dose to the targets and spare more critical organs in lung cancer than can 3D conformal radiotherapy (3DCRT). However, tumor-motion management and optimized radiotherapy planning based on four-dimensional computed tomography (4D CT) scanning are crucial to maximize the benefit of IMRT and to eliminate or minimize potential uncertainties. This article summarizes these strategies and reviews published findings supporting the safety and efficacy of IMRT for lung cancer. PMID:25771415

  5. Patterns of Failure and Toxicity after Intensity-Modulated Radiotherapy for Head and Neck Cancer

    SciTech Connect

    Schoenfeld, Gordon O.; Amdur, Robert J.; Morris, Christopher G.; Li, Jonathan G.; Hinerman, Russell W.; Mendenhall, William M.

    2008-06-01

    Purpose: To determine the outcome of patients treated with intensity-modulated radiotherapy (IMRT) for head and neck cancer. Methods and Materials: We reviewed the charts of 100 consecutive patients treated with IMRT for squamous cell carcinoma of the oropharynx (64%), nasopharynx (16%), hypopharynx (14%), and larynx (6%). Most patients were treated with a concomitant boost schedule to 72 Gy. Of the 100 patients, 54 (54%) received adjuvant chemotherapy, mostly concurrent cisplatin. The dosimetry plans for patients with either locoregional failure or Grade 4-5 complications were reviewed and fused over the computed tomography images corresponding with the location of the event. Marginal failures were defined as those that occurred at a region of high-dose falloff, where conventional fields would have provided better coverage. Results: The median follow-up of living patients was 3.1 years (range, 1-5.2 years). The 3-year rate of local control, locoregional control, freedom from relapse, cause-specific survival, and overall survival for all patients was 89%, 87%, 72%, 78%, and 71%, respectively. The 3-year rate of freedom from relapse, cause-specific survival, and overall survival for the 64 oropharynx patients was 86%, 92%, and 84%, respectively. Of the 10 local failures, 2 occurred at the margin of the high-dose planning target volume. Both regional failures occurred within the planning target volume. No locoregional failures occurred outside the planning target volume. Of the 100 patients, 8 and 5 had Grade 4 and 5 complications from treatment, respectively. All patients with Grade 5 complications had received adjuvant chemotherapy. No attempt was made to discriminate between the complications from IMRT and other aspects of the patients' treatment. Conclusion: Intensity-modulated radiotherapy did not compromise the outcome compared with what we have achieved with conventional techniques. The 2 cases of recurrence in the high-dose gradient region highlight the

  6. A Dosimetric Evaluation of Conventional Helmet Field Irradiation Versus Two-Field Intensity-Modulated Radiotherapy Technique

    SciTech Connect

    Yu, James B.; Shiao, Stephen L.; Knisely, Jonathan . E-mail: jonathan.knisely@yale.edu

    2007-06-01

    Purpose: To compare dosimetric differences between conventional two-beam helmet field irradiation (external beam radiotherapy, EBRT) of the brain and a two-field intensity-modulated radiotherapy (IMRT) technique. Methods and Materials: Ten patients who received helmet field irradiation at our institution were selected for study. External beam radiotherapy portals were planned per usual practice. Intensity-modulated radiotherapy fields were created using the identical field angles as the EBRT portals. Each brain was fully contoured along with the spinal cord to the bottom of the C2 vertebral body. This volume was then expanded symmetrically by 0.5 cm to construct the planning target volume. An IMRT plan was constructed using uniform optimization constraints. For both techniques, the nominal prescribed dose was 3,000 cGy in 10 fractions of 300 cGy using 6-MV photons. Comparative dose-volume histograms were generated for each patient and analyzed. Results: Intensity-modulated radiotherapy improved dose uniformity over EBRT for whole brain radiotherapy. The mean percentage of brain receiving >105% of dose was reduced from 29.3% with EBRT to 0.03% with IMRT. The mean maximum dose was reduced from 3,378 cGy (113%) for EBRT to 3,162 cGy (105%) with IMRT. The mean percent volume receiving at least 98% of the prescribed dose was 99.5% for the conventional technique and 100% for IMRT. Conclusions: Intensity-modulated radiotherapy reduces dose inhomogeneity, particularly for the midline frontal lobe structures where hot spots occur with conventional two-field EBRT. More study needs to be done addressing the clinical implications of optimizing dose uniformity and its effect on long-term cognitive function in selected long-lived patients.

  7. Intensity-Modulated Radiotherapy-Based Stereotactic Body Radiotherapy for Medically Inoperable Early-Stage Lung Cancer: Excellent Local Control

    SciTech Connect

    Videtic, Gregory M.M.; Stephans, Kevin; Reddy, Chandana; Gajdos, Stephen; Kolar, Matthew; Clouser, Edward; Djemil, Toufik

    2010-06-01

    Purpose: To validate the use of stereotactic body radiotherapy (SBRT) using intensity-modulated radiotherapy (IMRT) beams for medically inoperable Stage I lung cancer. Methods and Materials: From February 2004 to November 2006, a total of 26 patients with 28 lesions received SBRT using a Novalis/BrainLAB system. Immobilization involved a Bodyfix vacuum cushion. A weighted abdominal belt limited respiratory excursion. Computed tomographic simulation images were acquired at rest, full inhalation, and full exhalation and were merged to generate an internal gross tumor volume (ITV). Dose was prescribed to cover the planning target volume (PTV), defined as PTV = ITV + 3-5 mm set-up margin. Heterogeneity corrections were used. Delivery of 50 Gy in five sequential fractions typically used seven nonopposing, noncoplanar beams. Image-guided target verification was provided by BrainLAB-ExacTrac. Results: Among the 26 patients, the mean age was 74 years (range, 49-88 years). Of the patients, 50% were male and 50% female. The median Karnofsky performance status was 70 (range, 40-100). The median follow-up was 30.9 months (range, 10.4-51.4 months). Tissue diagnosis was contraindicated in seven patients (26.9%). There were 22 T1 (78.6%) and six T2 (21.4%) tumors. The median conformality index was 1.38 (range, 1.12-1.8). The median heterogeneity index was 1.08 (range, 1.04-1.2). One patient (3.6%) developed acute Grade 3 dyspnea and one patient developed late Grade 2 chest wall pain. Actuarial local control and overall survival at 3 years were 94.4% and 52%, respectively. Conclusions: Use of IMRT-based delivery of SBRT using restriction of tumor motion in medically inoperable lung cancer demonstrates excellent local control and favorable survival.

  8. Dose to the intracranial arteries in stereotactic and intensity-modulated radiotherapy for skull base tumors

    SciTech Connect

    Nieder, Carsten . E-mail: cnied@hotmail.com; Grosu, Anca L.; Stark, Sybille; Wiedenmann, Nicole; Busch, Raymonde; Kneschaurek, Peter; Molls, Michael

    2006-03-15

    Purpose: To examine retrospectively the maximum dose to the large skull base/intracranial arteries in fractionated stereotactic radiotherapy (FSRT) and intensity-modulated radiotherapy (IMRT), because of the potential risk of perfusion disturbances. Methods and Materials: Overall, 56 patients with tumors adjacent to at least one major artery were analyzed. Our strategy was to perform FSRT with these criteria: 1.8 Gy per fraction, planning target volume (PTV) enclosed by the 95% isodose, maximum dose 107%. Dose limits were applied to established organs at risk, but not the vessels. If FSRT planning failed to meet any of these criteria, IMRT was planned with the same objectives. Results: In 31 patients (median PTV, 23 cm{sup 3}), the FSRT plan fulfilled all criteria. No artery received a dose {>=}105%. Twenty-five patients (median PTV, 39 cm{sup 3}) needed IMRT planning. In 11 of 25 patients (median PTV, 85 cm{sup 3}), no plan satisfying all our criteria could be calculated. Only in this group, moderately increased maximum vessel doses were observed (106-110%, n = 7, median PTV, 121 cm{sup 3}). The median PTV dose gradient was 29% (significantly different from the 14 patients with satisfactory IMRT plans). Three of the four patients in this group had paranasal sinus tumors. Conclusion: The doses to the major arteries should be calculated in IMRT planning for critical tumor locations if a dose gradient >13% within the PTV can not be avoided because the PTV is large or includes air cavities.

  9. Use of 3D-printers to create intensity-modulated radiotherapy compensator blocks.

    PubMed

    Avelino, Samuel R; Silva, Luis Felipe O; Miosso, Cristiano J

    2012-01-01

    Intensity-Modulated Radiotherapy (IMRT) is an important tool for cancer treatment. It concentrates high radiation doses in complex target volumes, while sparing the surrounding tissues. IMRT is traditionally performed using Multileaf Collimators (MLC) or Compensator Blocks. The conventional way used to manufacture IMRT compensator blocks, which uses milling machines, is an important drawback over the MLC method, due to high operational and production costs. In this research, we developed a simpler alternative method to manufacture an IMRT compensator block from a fluency map generated by a commercial treatment planning system (TPS). This map was converted into a mold, and then printed using a 3D printer. The final IMRT compensator block was achieved by filling the mold with cerrobend alloy. To validate this method a quality assurance was performed using dosimetric films to compare the measured dose distributions to those predicted by the TPS system. This comparison showed a good agreement among 8 dose profiles from each situation, with a maximum RMS error of 8.84 % for the tested profiles. This suggests that the 3D printers can be effectively used to manufacture IMRT compensator blocks. The main advantage to this approach is that it can be fully conducted inside a radiotherapy facility, which results in lower costs and production times.

  10. Accelerated partial-breast irradiation using intensity-modulated proton radiotherapy: do uncertainties outweigh potential benefits?

    PubMed Central

    Wang, X; Zhang, X; Li, X; Amos, R A; Shaitelman, S F; Hoffman, K; Howell, R; Salehpour, M; Zhang, S X; Sun, T L; Smith, B; Tereffe, W; Perkins, G H; Buchholz, T A; Strom, E A

    2013-01-01

    Objective: Passive scattering proton beam (PSPB) radiotherapy for accelerated partial-breast irradiation (APBI) provides superior dosimetry for APBI three-dimensional conformal photon radiotherapy (3DCRT). Here we examine the potential incremental benefit of intensity-modulated proton radiotherapy (IMPT) for APBI and compare its dosimetry with PSPB and 3DCRT. Methods: Two theoretical IMPT plans, TANGENT_PAIR and TANGENT_ENFACE, were created for 11 patients previously treated with 3DCRT APBI and were compared with PSPB and 3DCRT plans for the same CT data sets. The impact of range, motion and set-up uncertainties as well as scanned spot mismatching between fields of IMPT plans was evaluated. Results: IMPT plans for APBI were significantly better regarding breast skin sparing (p<0.005) and other normal tissue sparing than 3DCRT plans (p<0.01) with comparable target coverage (p=ns). IMPT plans were statistically better than PSPB plans regarding breast skin (p<0.002) and non-target breast (p<0.007) in higher dose regions but worse or comparable in lower dose regions. IMPT plans using TANGENT_ENFACE were superior to that using TANGENT_PAIR in terms of target coverage (p<0.003) and normal tissue sparing (p<0.05) in low-dose regions. IMPT uncertainties were demonstrated for multiple causes. Qualitative comparison of dose–volume histogram confidence intervals for IMPT suggests that numeric gains may be offset by IMPT uncertainties. Conclusion: Using current clinical dosimetry, PSPB provides excellent dosimetry compared with 3DCRT with fewer uncertainties compared with IMPT. Advances in knowledge: As currently delivered in the clinic, PSPB planning for APBI provides as good or better dosimetry than IMPT with less uncertainty. PMID:23728947

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

    SciTech Connect

    Samuelian, Jason M.; Callister, Matthew D.; Ashman, Jonathan B.; Young-Fadok, Tonia M.; Borad, Mitesh J.; Gunderson, Leonard L.

    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

  12. Optimization of intensity modulated radiotherapy under constraints for static and dynamic MLC delivery.

    PubMed

    Alber, M; Nüsslin, F

    2001-12-01

    Multi-leaf collimators (MLCs) are emerging as the prevalent modality to apply intensity modulated radiotherapy (IMRT). Both the principle and the particular design of MLCs stipulate complex constraints on the practically applicable intensity modulated radiation fields. Most consequentially, the distribution of exposure times across the maximum field outline is either a piecewise constant function in the static mode or a piecewise linear function in the dynamic mode of driving an MLC. In view of clinical utility, the total leaf movement should be minimized, which requires that MLC-related constraints be considered in the dose optimization process. A method is proposed to achieve this for both static MLC fields and dynamic leaf close-in application. The method is an amendment to a generic gradient-based IMRT dose optimization algorithm and solves numerical problems related to the non-convexity of the MLC constraints, which can cause erratic behaviour of a gradient-based algorithm. It employs bistable penalty functions to select preferrable leaf configurations from the configuration space of the MLC, which is limited by specific design features. Together with an 'annealing' escape mechanism from local minima, the algorithm is capable of finding the optimum of an IMRT problem as leaf sequences with minimized leaf travel. In particular, the efficiency of static IMRT can be raised to the levels of unmodulated fields with very few field segments, thereby increasing the utility of IMRT in clinical practice.

  13. Simple Carotid-Sparing Intensity-Modulated Radiotherapy Technique and Preliminary Experience for T1-2 Glottic Cancer

    SciTech Connect

    Rosenthal, David I.; Fuller, Clifton D.; Barker, Jerry L.; Mason, Bryan M.S.; Garcia, John A. C.; Lewin, Jan S.; Holsinger, F. Christopher; Stasney, C. Richard; Frank, Steven J.; Schwartz, David L.; Morrison, William H.; Garden, Adam S.; Ang, K. Kian

    2010-06-01

    Purpose: To investigate the dosimetry and feasibility of carotid-sparing intensity-modulated radiotherapy (IMRT) for early glottic cancer and to report preliminary clinical experience. Methods and Materials: Digital Imaging and Communications in Medicine radiotherapy (DICOM-RT) datasets from 6 T1-2 conventionally treated glottic cancer patients were used to create both conventional IMRT plans. We developed a simplified IMRT planning algorithm with three fields and limited segments. Conventional and IMRT plans were compared using generalized equivalent uniform dose and dose-volume parameters for in-field carotid arteries, target volumes, and organs at risk. We have treated 11 patients with this simplified IMRT technique. Results: Intensity-modulated radiotherapy consistently reduced radiation dose to the carotid arteries (p < 0.05) while maintaining the clinical target volume coverage. With conventional planning, median carotid V35, V50, and V63 were 100%, 100%, and 69.0%, respectively. With IMRT planning these decreased to 2%, 0%, and 0%, respectively (p < 0.01). Radiation planning and treatment times were similar for conventional radiotherapy and IMRT. Treatment results have been excellent thus far. Conclusions: Intensity-modulated radiotherapy significantly reduced unnecessary radiation dose to the carotid arteries compared with conventional lateral fields while maintaining clinical target volume coverage. Further experience and longer follow-up will be required to demonstrate outcomes for cancer control and carotid artery effects.

  14. Intensity-modulated stereotactic body radiotherapy for stage I non-small cell lung cancer.

    PubMed

    Kim, Min-Jeong; Yeo, Seung-Gu; Kim, Eun Seok; Min, Chul Kee; Se An, Pyung

    2013-03-01

    This study aimed to investigate the clinical outcomes of intensity-modulated radiotherapy (IMRT)-based stereotactic body radiotherapy (SBRT) for patients with stage I non-small cell lung cancer (NSCLC). A prospective database of 16 consecutive patients receiving SBRT for pathologically-proven and peripherally-located stage I NSCLC was reviewed. Fifteen patients were medically inoperable and one patient refused to undergo surgery. The median age of the patients was 76 years (range, 69-86). Treatment planning used four-dimensional computed tomography and fixed-field IMRT (n=11) or volumetric-modulated arc therapy (VMAT; n=5). The SBRT scheme was 48 Gy in four fractions (n=9) or 55 Gy in five fractions (n=7), delivered on consecutive days. The overall response rate at 6 months was 78.6%, including a complete response in three (21.4%) patients and a partial response in eight (57.1%). Three patients (21.4%) demonstrated a stable disease status. The median follow-up time was 14 months (range, 6-20) for the surviving patients. One patient developed local failure at 11 months, while another suffered from regional failure in a subcarinal lymph node at 4 months. Two patients did not survive within the first 6 months; one patient died during salvage chemotherapy for mediastinal lymph node metastasis and the other succumbed to a cause unrelated to lung cancer. The Kaplan-Meier estimates of local failure-free, progression-free and overall survival rates at 18 months were 91.0, 85.2 and 87.5%, respectively. The toxicity was mild; no severe (grade ≥3) toxicity was identified. IMRT-based (including VMAT) delivery of SBRT for patients with stage I NSCLC demonstrated favorable responses and local control without severe toxicity.

  15. Siemens Multileaf Collimator Characterization and Quality Assurance Approaches for Intensity-Modulated Radiotherapy

    SciTech Connect

    Bayouth, John E.

    2008-05-01

    Application of the multileaf collimator (MLC) has evolved from replacing blocks to create treatment fields to creating photon fluence modulation for intensity-modulated radiotherapy (IMRT). Multileaf collimator system performance requirements are far more stringent for such applications and will require increased performance for future applications, such as motion tracking. This article reviews Siemens MLC systems, including a technical description and dosimetric characteristics of 56-, 82-, and 160-leaf designs. Routine quality assurance of MLC for IMRT necessitates frequent and critical assessment of MLC leaf position calibration errors that can present in many different ways (e.g., accuracy, reproducibility, longevity, hysteresis, and collimator/gantry angle dependencies). Several techniques for measuring these errors are presented, along with qualitative and quantitative techniques for analyzing results. In particular, increased accuracy of leaf position measurement at variable gantry angles is enabled by spatial transformations to electronic portal imaging device position quantified by calibration protocols introduced with megavoltage cone beam. Measured values of X-ray transmission (intra-leaf, inter-leaf, and through abutting leaf pairs) and penumbra (leaf end, leaf tongue, leaf groove) are presented with an evaluation of their characterization by a treatment-planning system. The dosimetric impact of planning system model inadequacies is demonstrated for collimator scatter, dose profile values within 30 mm of the field edge, and the resultant effect demonstrated on clinical cases. Finally, a description of automated quality assurance delivery, analysis, and calibration protocols applicable for the specific vendor's system is provided.

  16. Assessment of Extended-Field Radiotherapy for Stage IIIC Endometrial Cancer Using Three-Dimensional Conformal Radiotherapy, Intensity-Modulated Radiotherapy, and Helical Tomotherapy

    SciTech Connect

    Lian Jidong Mackenzie, Marc; Joseph, Kurian; Pervez, Nadeem; Dundas, George; Urtasun, Raul; Pearcey, Robert

    2008-03-01

    Purpose: To perform a dosimetric comparison of three-dimensional conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and helical tomotherapy (HT) plans for pelvic and para-aortic RT in postoperative endometrial cancer patients; and to evaluate the integral dose (ID) received by critical structures within the radiation fields. Methods and Materials: We selected 10 patients with Stage IIIC endometrial cancer. For each patient, three plans were created with 3D-CRT, IMRT, and HT. The IMRT and HT plans were both optimized to keep the mean dose to the planning target volume (PTV) the same as that with 3D-CRT. The dosimetry and ID for the critical structures were compared. A paired two-tailed Student t test was used for data analysis. Results: Compared with the 3D-CRT plans, the IMRT plans resulted in lower IDs in the organs at risk (OARs), ranging from -3.49% to -17.59%. The HT plans showed a similar result except that the ID for the bowel increased 0.27%. The IMRT and HT plans both increased the IDs to normal tissue (see and text for definition), pelvic bone, and spine (range, 3.31-19.7%). The IMRT and HT dosimetry showed superior PTV coverage and better OAR sparing than the 3D-CRT dosimetry. Compared directly with IMRT, HT showed similar PTV coverage, lower Ids, and a decreased dose to most OARs. Conclusion: Intensity-modulated RT and HT appear to achieve excellent PTV coverage and better sparing of OARs, but at the expense of increased IDs to normal tissue and skeleton. HT allows for additional improvement in dosimetry and sparing of most OARs.

  17. Intensity-Modulated Whole Abdominal Radiotherapy After Surgery and Carboplatin/Taxane Chemotherapy for Advanced Ovarian Cancer: Phase I Study

    SciTech Connect

    Rochet, Nathalie; Sterzing, Florian; Jensen, Alexandra D.; Dinkel, Julien; Herfarth, Klaus K.; Schubert, Kai; Eichbaum, Michael H.; Schneeweiss, Andreas; Sohn, Christof; Debus, Juergen; Harms, Wolfgang

    2010-04-15

    Purpose: To assess the feasibility and toxicity of consolidative intensity-modulated whole abdominal radiotherapy (WAR) after surgery and chemotherapy in high-risk patients with advanced ovarian cancer. Methods and Materials: Ten patients with optimally debulked ovarian cancer International Federation of Gynecology and Obstetrics Stage IIIc were treated in a Phase I study with intensity-modulated WAR up to a total dose of 30 Gy in 1.5-Gy fractions as consolidation therapy after adjuvant carboplatin/taxane chemotherapy. Treatment was delivered using intensity-modulated radiotherapy in a step-and-shoot technique (n = 3) or a helical tomotherapy technique (n = 7). The planning target volume included the entire peritoneal cavity and the pelvic and para-aortal node regions. Organs at risk were kidneys, liver, heart, vertebral bodies, and pelvic bones. Results: Intensity-modulated WAR resulted in an excellent coverage of the planning target volume and an effective sparing of the organs at risk. The treatment was well tolerated, and no severe Grade 4 acute side effects occurred. Common Toxicity Criteria Grade III toxicities were as follows: diarrhea (n = 1), thrombocytopenia (n = 1), and leukopenia (n = 3). Radiotherapy could be completed by all the patients without any toxicity-related interruption. Median follow-up was 23 months, and 4 patients had tumor recurrence (intraperitoneal progression, n = 3; hepatic metastasis, n = 1). Small bowel obstruction caused by adhesions occurred in 3 patients. Conclusions: The results of this Phase I study showed for the first time, to our knowledge, the clinical feasibility of intensity-modulated whole abdominal radiotherapy, which could offer a new therapeutic option for consolidation treatment of advanced ovarian carcinoma after adjuvant chemotherapy in selected subgroups of patients. We initiated a Phase II study to further evaluate the toxicity of this intensive multimodal treatment.

  18. Phase II Trial of Hypofractionated Image-Guided Intensity-Modulated Radiotherapy for Localized Prostate Adenocarcinoma

    SciTech Connect

    Martin, Jarad M.; Rosewall, Tara; Bayley, Andrew; Bristow, Robert; Chung, Peter; Crook, Juanita; Gospodarowicz, Mary; McLean, Michael; Menard, Cynthia; Milosevic, Michael; Warde, Padraig; Catton, Charles

    2007-11-15

    Purpose: To assess in a prospective trial the feasibility and late toxicity of hypofractionated radiotherapy (RT) for prostate cancer. Methods and Materials: Eligible patients had clinical stage T1c-2cNXM0 disease. They received 60 Gy in 20 fractions over 4 weeks with intensity-modulated radiotherapy including daily on-line image guidance with intraprostatic fiducial markers. Results: Between June 2001 and March 2004, 92 patients were treated with hypofractionated RT. The cohort had a median prostate-specific antigen value of 7.06 ng/mL. The majority had Gleason grade 5-6 (38%) or 7 (59%) disease, and 82 patients had T1c-T2a clinical staging. Overall, 29 patients had low-risk, 56 intermediate-risk, and 7 high-risk disease. Severe acute toxicity (Grade 3-4) was rare, occurring in only 1 patient. Median follow-up was 38 months. According to the Phoenix definition for biochemical failure, the rate of biochemical control at 14 months was 97%. According to the previous American Society for Therapeutic Radiology and Oncology definition, biochemical control at 3 years was 76%. The incidence of late toxicity was low, with no severe (Grade {>=}3) toxicity at the most recent assessment. Conclusions: Hypofractionated RT using 60 Gy in 20 fractions over 4 weeks with image guidance is feasible and is associated with low rates of late bladder and rectal toxicity. At early follow-up, biochemical outcome is comparable to that reported for conventionally fractionated controls. The findings are being tested in an ongoing, multicenter, Phase III trial.

  19. Implementing intensity modulated radiotherapy to the prostate bed: Dosimetric study and early clinical results

    SciTech Connect

    Riou, Olivier; Laliberté, Benoit; Azria, David; Menkarios, Cathy; Llacer Moscardo, Carmen; Dubois, Jean-Bernard; Aillères, Norbert; Fenoglietto, Pascal

    2013-07-01

    Salvage intensity modulated radiotherapy (IMRT) to the prostate bed has hardly been studied so far. We present here a feasibility study and early clinical results for 10 patients. These patients were selected on the basis of having either a biochemical relapse or high risk histology after prostatectomy. They were treated using “sliding-window” IMRT to 68 Gy in 34 fractions. Three-dimensional conformal radiotherapy (3D-CRT) plans were generated using the same planning computed tomography data set. Dose coverage of planning target volumes (PTVs) and of organs-at-risk (OAR, namely: rectum, bladder, and femoral heads) were compared. Acute toxicity and chronic toxicity were measured using the Common Toxicity Criteria for Adverse Events version 3.0 scale. IMRT significantly reduces the dose above the prescription dose given to the PTV1 (mean dose: IMRT 67.2 Gy vs 3D-CRT 67.7 Gy (p = 0.0137)), without altering dose coverage for PTV2 (mean dose: IMRT 68.1 Gy vs 3D-CRT 68.0 Gy (p = 0.3750)). Doses to OAR were lower with IMRT and differences were statistically significant (mean dose: IMRT 51.4 Gy vs 3D-CRT 56.6 Gy for rectum (p = 0.002), IMRT 45.1 Gy vs 3D-CRT 53.1 Gy for bladder (p = 0.002), and IMRT 26.1 Gy vs 3D-CRT 28.4 Gy for femoral heads (p = 0.0059)). There was no acute or chronic genitourinary or gastrointestinal toxicity >1 with a median follow-up of 38 months. IMRT to the prostatic fossa is feasible and reduces dose to OAR, with consequential limited toxicity.

  20. Dose-Dependent Pulmonary Toxicity After Postoperative Intensity-Modulated Radiotherapy for Malignant Pleural Mesothelioma

    SciTech Connect

    Rice, David C. Smythe, W. Roy; Liao Zhongxing; Guerrero, Thomas; Chang, Joe Y.; McAleer, Mary F.; Jeter, Melenda D.; Correa, Arlene Ph.D.; Vaporciyan, Ara A.; Liu, H. Helen; Komaki, Ritsuko; Forster, Kenneth M.; Stevens, Craig W.

    2007-10-01

    Purpose: To determine the incidence of fatal pulmonary events after extrapleural pneumonectomy and hemithoracic intensity-modulated radiotherapy (IMRT) for malignant pleural mesothelioma. Methods and Materials: We retrospectively reviewed the records of 63 consecutive patients with malignant pleural mesothelioma who underwent extrapleural pneumonectomy and IMRT at University of Texas M. D. Anderson Cancer Center. The endpoints studied were pulmonary-related death (PRD) and non-cancer-related death within 6 months of IMRT. Results: Of the 63 patients, 23 (37%) had died within 6 months of IMRT (10 of recurrent cancer, 6 of pulmonary causes [pneumonia in 4 and pneumonitis in 2], and 7 of other noncancer causes [pulmonary embolus in 2, sepsis after bronchopleural fistula in 1, and cause unknown but without pulmonary symptoms or recurrent disease in 4]). On univariate analysis, the factors that predicted for PRD were a lower preoperative ejection fraction (p = 0.021), absolute volume of lung spared at 10 Gy (p = 0.025), percentage of lung volume receiving {>=}20 Gy (V{sub 20}; p 0.002), and mean lung dose (p = 0.013). On multivariate analysis, only V{sub 20} was predictive of PRD (p = 0.017; odds ratio, 1.50; 95% confidence interval, 1.08-2.08) or non-cancer-related death (p = 0.033; odds ratio, 1.21; 95% confidence interval, 1.02-1.45). Conclusion: The results of our study have shown that fatal pulmonary toxicities were associated with radiation to the contralateral lung. V{sub 20} was the only independent determinant for risk of PRD or non-cancer-related death. The mean V{sub 20} of the non-PRD patients was considerably lower than that accepted during standard thoracic radiotherapy, implying that the V{sub 20} should be kept as low as possible after extrapleural pneumonectomy.

  1. The Effect of Intensity-Modulated Radiotherapy on Radiation-Induced Second Malignancies

    SciTech Connect

    Ruben, Jeremy D. Davis, Sidney; Evans, Cherie; Jones, Phillip; Gagliardi, Frank; Haynes, Matthew; Hunter, Alistair

    2008-04-01

    Purpose: To compare intensity-modulated radiotherapy (IMRT) with three-dimensional conformal radiotherapy (3D-CRT) in terms of carcinogenic risk for actual clinical scenarios. Method and Materials: Clinically equivalent IMRT plans were generated for prostate, breast, and head-and-neck cases treated with 3D-CRT. Two possible dose-response models for radiocarcinogenesis were generated based on A-bomb survivor data corrected for fractionation. Dose-volume histogram analysis was used to determine dose and its distribution to nontargeted tissues within the planning CT scan volume and thermoluminescent dosimetry for the rest of the body. Carcinogenic estimates were calculated with and without a correction factor accounting for cancer patients' advanced age and reduced longevity. Results: For the model assuming a plateau in risk above 2-Gy single-fraction-equivalent (SFE), IMRT and 3D-CRT produced risks of 1.7% and 2.1%, respectively, for prostate; 1.9% and 1.8%, respectively, for nasopharynx; 1% each for tonsil; and 1.4-2.2% and 1.5-1.6%, respectively, depending on technique, for breast. Assuming a reduction in risk above 2-Gy SFE, risks for IMRT and 3D-CRT were 1.1% and 1.5%, respectively, for prostate; 1.4% and 1.2%, respectively, for nasopharynx; 1% each for tonsil; and 1.3-1.8% vs. 1.3-1.6%, respectively, for breast. Applying a correction factor of 0.5 for cancer patients halved these risks and their relative differences. Conclusions: Carcinogenic risks were comparable in absolute terms between modalities. Risks are dependant on technique used. Risks with IMRT are influenced by monitor unit demand and are therefore software/hardware dependant. The dose-response model accounting for cell killing at higher doses fitted best with actual observed risks.

  2. Accelerated Whole Breast Irradiation With Intensity-Modulated Radiotherapy to the Prone Breast

    SciTech Connect

    Croog, Victoria J.; Wu, Abraham J.; McCormick, Beryl; Beal, Kathryn P.

    2009-01-01

    Purpose: Whole breast irradiation (WBI) is the standard of care for patients with early-stage breast cancer who opt for breast conservation. After a randomized trial demonstrated equivalent cosmesis and disease control with accelerated WBI (AWBI), our institution began to offer AWBI to appropriate patients. The aim of this study was to examine our unique experience with AWBI using prone positioning and simplified intensity-modulated radiotherapy (IMRT) planning with a sequential boost to the tumor bed. Methods and Materials: We identified 356 patients who had been treated with prone WBI using IMRT in our department between January 2004 and December 2006. Of these, 128 (36%) patients had received AWBI (representing 131 treated breasts), consisting of 16 daily fractions of 265 cGy to a total dose of 4,240 cGy followed by a conventionally fractionated boost. Results: Patients who opted for AWBI were similar demographically to the patients undergoing conventional WBI. In the AWBI cohort, 83% of the patients had Stage T1 disease and 22% had nodal involvement (N1). The tumors were estrogen receptor-positive, progesterone receptor-positive and Her-2/Neu-amplified in 82%, 69%, and 11%, respectively. The median duration of AWBI plus a boost was 29 days, and no patient required a toxicity-related treatment break. No Grade 3 or greater acute toxicity developed. At a median follow-up of 18 months, one ipsilateral breast recurrence developed that was salvaged with mastectomy and immediate reconstruction. Conclusion: AWBI to the prone breast using simplified IMRT with a sequential boost offers women requiring breast-only adjuvant radiotherapy an abbreviated treatment with early tumor control and cosmesis comparable to that with standard fractionation.

  3. Feasibility Study of Intensity-Modulated Radiotherapy (IMRT) Treatment Planning Using Brain Functional MRI

    SciTech Connect

    Chang Jenghwa Kowalski, Alex; Hou, Bob; Narayana, Ashwatha

    2008-04-01

    The purpose of this work was to study the feasibility of incorporating functional magnetic resonance imaging (fMRI) information for intensity modulated radiotherapy (IMRT) treatment planning of brain tumors. Three glioma patients were retrospectively replanned for radiotherapy (RT) with additional fMRI information. The fMRI of each patient was acquired using a bilateral finger-tapping paradigm with a gradient echo EPI (Echo Planer Imaging) sequence. The fMRI data were processed using the Analysis of Functional Neuroimaging (AFNI) software package for determining activation volumes, and the volumes were fused with the simulation computed tomography (CT) scan. The actived pixels in left and right primary motor cortexes (PMCs) were contoured as critical structures for IMRT planning. The goal of replanning was to minimize the RT dose to the activation volumes in the PMC regions, while maintaining a similar coverage to the planning target volume (PTV) and keeping critical structures within accepted dose tolerance. Dose-volume histograms of the treatment plans with and without considering the fMRI information were compared. Beam angles adjustment or additional beams were needed for 2 cases to meet the planning criteria. Mean dose to the contralateral and ipsilateral PMC was significantly reduced by 66% and 55%, respectively, for 1 patient. For the other 2 patients, mean dose to contralateral PMC region was lowered by 73% and 69%. In general, IMRT optimization can reduce the RT dose to the PMC regions without compromising the PTV coverage or sparing of other critical organs. In conclusion, it is feasible to incorporate the fMRI information into the RT treatment planning. IMRT planning allows a significant reduction in RT dose to the PMC regions, especially if the region does not lie within the PTV.

  4. Retrospective estimate of the quality of intensity-modulated radiotherapy plans for lung cancer

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    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 by using the conformity index (CI), coverage index (CVI), and homogeneity index (HI) of the planning target volume (PTV), the OAR-PTV distance and the OAR-PTV overlap volume, and the V10 Gy , V20 Gy , and equivalent uniform dose (EUD) of the OARs. The CI, CVI, and HI of the PTV were 0.54-0.89 (0.77 ± 0.08), 0.90-1.00 (0.98 ± 0.02), and 0.11-0.41, (0.15 ± 0.05), respectively. The mean EUDs (V10 Gy , V20 Gy ) 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), respectively. EUDs tended to decrease as the OAR-PTV distance increased and the OAR-PTV overlap volume decreased. Because the plans in this study were from a single department, relatively few people were involved in treatment planning. Differences in treatment results for a given patient would be much more pronounced if many departments were involved.

  5. Whole-Field Simultaneous Integrated-Boost Intensity-Modulated Radiotherapy for Patients With Nasopharyngeal Carcinoma

    SciTech Connect

    Wong, Frank C.S.; Ng, Alice W.Y.; Lee, Victor H.F.; Lui, Collin M.M.; Yuen, K.-K.; Sze, W.-K.; Leung, T.-W.; Tung, Stewart Y.

    2010-01-15

    Purpose: To retrospectively review the outcomes of our patients with newly diagnosed nondisseminated nasopharyngeal carcinoma treated with intensity-modulated radiotherapy using a whole-field simultaneous integrated-boost technique. Methods and Materials: A total of 175 patients treated with WF-SIB between mid-2004 and 2005 were eligible for study inclusion. The distribution of disease by stage was Stage IA in 10.9%, Stage IIA in 2.3%, Stage IIB in 21.7%, Stage III in 41.1%, Stage IVA in 14.9%, and Stage IVB in 9.1%. Of the 175 patients, 2 (1.2%), 10 (5.7%), and 163 (93.1%) had World Health Organization type I, II, and III histologic features, respectively. We prescribed 70 Gy, 60 Gy, and 54 Gy delivered in 33 fractions within 6.5 weeks at the periphery of three planning target volumes (PTV; PTV70, PTV60, and PTV54, respectively). Of the 175 patients, 46 with early T-stage disease received a brachytherapy boost, and 127 with advanced local or regional disease received chemotherapy. Results: The median follow-up period was 34 months. The overall 3-year local failure-free survival, regional failure-free survival, distant failure-free survival, and overall survival rate was 93.6%, 93.3%, 86.6%, and 87.2%, respectively. Cox regression analysis showed Stage N2-N3 disease (p = .029) and PTV (p = .024) to be independent factors predicting a greater risk of distant failure and poor overall survival, respectively. Grade 3 acute mucositis/pharyngitis occurred in 23.4% of patients, and Stage T4 disease was the only significant predictor of mucositis/pharyngitis (p = .021). Conclusion: Whole-field simultaneous integrated-boost intensity-modulated radiotherapy with a dose >70 Gy achieved excellent locoregional control, without an excess incidence of severe, acute mucositis/pharyngitis, in the present study. Strategies for using such highly conformal treatment for patients with a large tumor and late N-stage disease are potential areas of investigation for future studies.

  6. Intensity-Modulated Radiotherapy for Head-and-Neck Cancer in the Community Setting

    SciTech Connect

    Seung, Steven Bae, Joseph; Solhjem, Matthew; Bader, Stephen; Gannett, David; Hansen, Eric K.; Louie, Jeannie; Underhill, Kelly Cha Christine

    2008-11-15

    Purpose: To review outcomes with intensity-modulated radiation therapy (IMRT) in the community setting for the treatment of nasopharyngeal and oropharyngeal cancer. Methods and Materials: Between April 2003 and April 2007, 69 patients with histologically confirmed cancer of the nasopharynx and oropharynx underwent IMRT in our practice. The primary sites included nasopharynx (11), base of tongue (18), and tonsil (40). The disease stage distribution was as follows: 2 Stage I, 11 Stage II, 16 Stage III, and 40 Stage IV. All were treated with a simultaneous integrated boost IMRT technique. The median prescribed doses were 70 Gy to the planning target volume, 59.4 Gy to the high-risk subclinical volume, and 54 Gy to the low-risk subclinical volume. Forty-five patients (65%) received concurrent chemotherapy. Toxicity was graded according to the Radiation Therapy Oncology Group toxicity criteria. Progression-free and overall survival rates were estimated with the Kaplan-Meier product-limit method. Results: Median duration of follow-up was 18 months. The estimated 2-year local control, regional control, distant control, and overall survival rates were 98%, 100%, 98%, and 90%, respectively. The most common acute toxicities were dermatitis (32 Grade 1, 32 Grade 2, 5 Grade 3), mucositis (8 Grade 1, 33 Grade 2, 28 Grade 3), and xerostomia (0 Grade 1, 29 Grade 2, 40 Grade 3). Conclusions: Intensity-modulated radiotherapy in the community setting can be accomplished safely and effectively. Systematic internal review systems are recommended for quality control until sufficient experience develops.

  7. Dosimetric Evaluation of Different Intensity-Modulated Radiotherapy Techniques for Breast Cancer After Conservative Surgery.

    PubMed

    Zhang, Fuli; Wang, Yadi; Xu, Weidong; Jiang, Huayong; Liu, Qingzhi; Gao, Junmao; Yao, Bo; Hou, Jun; He, Heliang

    2015-10-01

    Intensity-modulated radiotherapy (IMRT) potentially leads to a more favorite dose distribution compared to 3-dimensional or conventional tangential radiotherapy (RT) for breast cancer after conservative surgery or mastectomy. The aim of this study was to compare dosimetric parameters of the planning target volume (PTV) and organs at risk (OARs) among helical tomotherapy (HT), inverse-planned IMRT (IP-IMRT), and forward-planned field in field (FP-FIF) IMRT techniques after breast-conserving surgery. Computed tomography scans from 20 patients (12 left sided and 8 right sided) previously treated with T1N0 carcinoma were selected for this dosimetric planning study. We designed HT, IP-IMRT, and FP-FIF plans for each patient. Plans were compared according to dose-volume histogram analysis in terms of PTV homogeneity and conformity indices (HI and CI) as well as OARs dose and volume parameters. Both HI and CI of the PTV showed statistically significant difference among IP-IMRT, FP-FIF, and HT with those of HT were best (P < .05). Compared to FP-FIF, IP-IMRT showed smaller exposed volumes of ipsilateral lung, heart, contralateral lung, and breast, while HT indicated smaller exposed volumes of ipsilateral lung but larger exposed volumes of contralateral lung and breast as well as heart. In addition, HT demonstrated an increase in exposed volume of ipsilateral lung (except for fraction of lung volume receiving >30 Gy and 20 Gy), heart, contralateral lung, and breast compared with IP-IMRT. For breast cancer radiotherapy (RT) after conservative surgery, HT provides better dose homogeneity and conformity of PTV compared to IP-IMRT and FP-FIF techniques, especially for patients with supraclavicular lymph nodes involved. Meanwhile, HT decreases the OAR volumes receiving higher doses with an increase in the volumes receiving low doses, which is known to lead to an increased rate of radiation-induced secondary malignancies. Hence, composite factors including dosimetric advantage

  8. The importance of prostate bed tilt during postprostatectomy intensity-modulated radiotherapy.

    PubMed

    Bell, Linda J; Cox, Jennifer; Eade, Thomas; Rinks, Marianne; Kneebone, Andrew

    2014-01-01

    Variations in rectal and bladder filling can create a tilt of the prostate bed, which generates the potential for a geographic miss during postprostatectomy radiotherapy. The aim of this study is to assess the effect that bladder and rectum filling has on planning target volume angle, to determine a method to assess prostate bed tilt leading to potential geographic miss, and to discuss possible implementation issues. The cone-beam computed tomography images (n = 377) of 40 patients who received postprostatectomy radiotherapy with intensity-modulated radiotherapy were reviewed. The amount of tilt in the prostate bed was defined as the angle change between 2 surgical clips, one in the upper prostate bed and another in the lower. A potential geographic miss was defined as movement of any clip of more than 1cm in any direction or 0.5 cm posteriorly when aligned to bone anatomy. Variations in bladder and rectum size were correlated with the degree of prostate bed tilt, and the rate of potential geographic miss was determined. A possible clinical use of prostate bed tilt was then assessed for different imaging techniques. A tilt of more than 10° was seen in 20.2% of images, which resulted in a 57.9% geographic miss rate of the superior clip. When tilt remained within 10°, there was only a 9% rate of geographic miss. Potential geographic miss of the inferior surgical clip was rare, occurring in only 1.9% of all images reviewed. The most common occurrence when the prostate bed tilt increased by more than 10° was a smaller bladder and larger rectum (6.4% of all images). The most common occurrence when the prostate bed tilt decreased by more than 10° was a larger bladder and smaller rectum (1.3% of all images). Significant prostate bed tilt (>± 10°) occurred in more than 20% of images, creating a 58% rate of geographic miss. Greatest prostate bed tilt occurred when the bladder size increased or reduced by more than 2 cm or the superior rectum size increased by more

  9. The importance of prostate bed tilt during postprostatectomy intensity-modulated radiotherapy

    SciTech Connect

    Bell, Linda J.; Cox, Jennifer; Eade, Thomas; Rinks, Marianne; Kneebone, Andrew

    2014-10-01

    Variations in rectal and bladder filling can create a tilt of the prostate bed, which generates the potential for a geographic miss during postprostatectomy radiotherapy. The aim of this study is to assess the effect that bladder and rectum filling has on planning target volume angle, to determine a method to assess prostate bed tilt leading to potential geographic miss, and to discuss possible implementation issues. The cone-beam computed tomography images (n = 377) of 40 patients who received postprostatectomy radiotherapy with intensity-modulated radiotherapy were reviewed. The amount of tilt in the prostate bed was defined as the angle change between 2 surgical clips, one in the upper prostate bed and another in the lower. A potential geographic miss was defined as movement of any clip of more than 1 cm in any direction or 0.5 cm posteriorly when aligned to bone anatomy. Variations in bladder and rectum size were correlated with the degree of prostate bed tilt, and the rate of potential geographic miss was determined. A possible clinical use of prostate bed tilt was then assessed for different imaging techniques. A tilt of more than 10° was seen in 20.2% of images, which resulted in a 57.9% geographic miss rate of the superior clip. When tilt remained within 10°, there was only a 9% rate of geographic miss. Potential geographic miss of the inferior surgical clip was rare, occurring in only 1.9% of all images reviewed. The most common occurrence when the prostate bed tilt increased by more than 10° was a smaller bladder and larger rectum (6.4% of all images). The most common occurrence when the prostate bed tilt decreased by more than 10° was a larger bladder and smaller rectum (1.3% of all images). Significant prostate bed tilt (>± 10°) occurred in more than 20% of images, creating a 58% rate of geographic miss. Greatest prostate bed tilt occurred when the bladder size increased or reduced by more than 2 cm or the superior rectum size increased by more

  10. Neural stem cell sparing by linac based intensity modulated stereotactic radiotherapy in intracranial tumors

    PubMed Central

    2013-01-01

    Background Neurocognitive decline observed after radiotherapy (RT) for brain tumors in long time survivors is attributed to radiation exposure of the hippocampus and the subventricular zone (SVZ). The potential of sparing capabilities for both structures by optimized intensity modulated stereotactic radiotherapy (IMSRT) is investigated. Methods Brain tumors were irradiated by stereotactic 3D conformal RT or IMSRT using m3 collimator optimized for PTV and for sparing of the conventional OARs (lens, retina, optic nerve, chiasm, cochlea, brain stem and the medulla oblongata). Retrospectively both hippocampi and SVZ were added to the list of OAR and their dose volume histograms were compared to those from two newly generated IMSRT plans using 7 or 14 beamlets (IMSRT-7, IMSRT-14) dedicated for optimized additional sparing of these structures. Conventional OAR constraints were kept constant. Impact of plan complexity and planning target volume (PTV) topography on sparing of both hippocampi and SVZ, conformity index (CI), the homogeneity index (HI) and quality of coverage (QoC) were analyzed. Limits of agreement were used to compare sparing of stem cell niches with either IMSRT-7 or IMSRT-14. The influence of treatment technique related to the topography ratio between PTV and OARs, realized in group A-D, was assessed by a mixed model. Results In 47 patients CI (p ≤ 0.003) and HI (p < 0.001) improved by IMSRT-7, IMSRT-14, QoC remained stable (p ≥ 0.50) indicating no compromise in radiotherapy. 90% of normal brain was exposed to a significantly higher dose using IMSRT. IMSRT-7 plans resulted in significantly lower biologically effective doses at all four neural stem cell structures, while contralateral neural stem cells are better spared compared to ipsilateral. A further increase of the number of beamlets (IMSRT-14) did not improve sparing significantly, so IMSRT-7 and IMSRT-14 can be used interchangeable. Patients with tumors contacting neither the

  11. Correcting radiation survey data to account for increased leakage during intensity modulated radiotherapy treatments

    SciTech Connect

    Kairn, T.; Crowe, S. B.; Trapp, J. V.

    2013-11-15

    Purpose: Intensity modulated radiotherapy (IMRT) treatments require more beam-on time and produce more linac head leakage to deliver similar doses to conventional, unmodulated, radiotherapy treatments. It is necessary to take this increased leakage into account when evaluating the results of radiation surveys around bunkers that are, or will be, used for IMRT. The recommended procedure of applying a monitor-unit based workload correction factor to secondary barrier survey measurements, to account for this increased leakage when evaluating radiation survey measurements around IMRT bunkers, can lead to potentially costly overestimation of the required barrier thickness. This study aims to provide initial guidance on the validity of reducing the value of the correction factor when applied to different radiation barriers (primary barriers, doors, maze walls, and other walls) by evaluating three different bunker designs.Methods: Radiation survey measurements of primary, scattered, and leakage radiation were obtained at each of five survey points around each of three different radiotherapy bunkers and the contribution of leakage to the total measured radiation dose at each point was evaluated. Measurements at each survey point were made with the linac gantry set to 12 equidistant positions from 0° to 330°, to assess the effects of radiation beam direction on the results.Results: For all three bunker designs, less than 0.5% of dose measured at and alongside the primary barriers, less than 25% of the dose measured outside the bunker doors and up to 100% of the dose measured outside other secondary barriers was found to be caused by linac head leakage.Conclusions: Results of this study suggest that IMRT workload corrections are unnecessary, for survey measurements made at and alongside primary barriers. Use of reduced IMRT workload correction factors is recommended when evaluating survey measurements around a bunker door, provided that a subset of the measurements used in

  12. Intensity-Modulated Radiotherapy Results in Significant Decrease in Clinical Toxicities Compared With Conventional Wedge-Based Breast Radiotherapy

    SciTech Connect

    Harsolia, Asif; Kestin, Larry; Grills, Inga; Wallace, Michelle; Jolly, Shruti; Jones, Cortney; Lala, Moinaktar; Martinez, Alvaro; Schell, Scott; Vicini, Frank A. . E-mail: fvicini@beaumont.edu

    2007-08-01

    Purpose: We have previously demonstrated that intensity-modulated radiotherapy (IMRT) with a static multileaf collimator process results in a more homogenous dose distribution compared with conventional wedge-based whole breast irradiation (WBI). In the present analysis, we reviewed the acute and chronic toxicity of this IMRT approach compared with conventional wedge-based treatment. Methods and Materials: A total of 172 patients with Stage 0-IIB breast cancer were treated with lumpectomy followed by WBI. All patients underwent treatment planning computed tomography and received WBI (median dose, 45 Gy) followed by a boost to 61 Gy. Of the 172 patients, 93 (54%) were treated with IMRT, and the 79 patients (46%) treated with wedge-based RT in a consecutive fashion immediately before this cohort served as the control group. The median follow-up was 4.7 years. Results: A significant reduction in acute Grade 2 or worse dermatitis, edema, and hyperpigmentation was seen with IMRT compared with wedges. A trend was found toward reduced acute Grade 3 or greater dermatitis (6% vs. 1%, p = 0.09) in favor of IMRT. Chronic Grade 2 or worse breast edema was significantly reduced with IMRT compared with conventional wedges. No difference was found in cosmesis scores between the two groups. In patients with larger breasts ({>=}1,600 cm{sup 3}, n = 64), IMRT resulted in reduced acute (Grade 2 or greater) breast edema (0% vs. 36%, p <0.001) and hyperpigmentation (3% vs. 41%, p 0.001) and chronic (Grade 2 or greater) long-term edema (3% vs. 30%, p 0.007). Conclusion: The use of IMRT in the treatment of the whole breast results in a significant decrease in acute dermatitis, edema, and hyperpigmentation and a reduction in the development of chronic breast edema compared with conventional wedge-based RT.

  13. Treatment Planning Study to Determine Potential Benefit of Intensity-Modulated Radiotherapy Versus Conformal Radiotherapy for Unresectable Hepatic Malignancies

    SciTech Connect

    Eccles, Cynthia L.; Bissonnette, Jean-Pierre; Craig, Tim; Taremi, Mojgan; Wu Xia; Dawson, Laura A.

    2008-10-01

    Purpose: To compare intensity-modulated radiotherapy (IMRT) with conformal RT (CRT) for hypofractionated isotoxicity liver RT and explore dose escalation using IMRT for the same/improved nominal risk of liver toxicity in a treatment planning study. Methods and Materials: A total of 26 CRT plans were evaluated. Prescription doses (24-54 Gy within six fractions) were individualized on the basis of the effective liver volume irradiated maintaining {<=}5% risk of radiation-induced liver disease. The dose constraints included bowel (0.5 cm{sup 3}) and stomach (0.5 cm{sup 3}) to {<=}30 Gy, spinal cord to {<=}25 Gy, and planning target volume (PTV) to {<=}140% of the prescribed dose. Two groups were evaluated: (1) PTV overlapping or directly adjacent to serial functioning normal tissues (n = 14), and (2) the liver as the dose-limiting normal tissue (n = 12). IMRT plans using direct machine parameter optimization maintained the CRT plan beam arrangements, an estimated radiation-induced liver disease risk of 5%, and underwent dose escalation, if all normal tissue constraints were maintained. Results: IMRT improved PTV coverage in 19 of 26 plans (73%). Dose escalation was feasible in 9 cases by an average of 3.8 Gy (range, 0.6-13.2) in six fractions. Three of seven plans without improved PTV coverage had small gross tumor volumes ({<=}105 cm{sup 3}) already receiving 54 Gy, the maximal prescription dose allowed. In the remaining cases, the PTV range was 9.6-689 cm{sup 3}; two had overlapped organs at risk; and one had four targets. IMRT did not improve these plans owing to poor target coverage (n = 2) and nonliver (n = 2) dose limits. Conclusion: Direct machine parameter optimization IMRT improved PTV coverage while maintaining normal tissue tolerances in most CRT liver plans. Dose escalation was possible in a minority of patients.

  14. Interfractional Dose Variations in Intensity-Modulated Radiotherapy With Breath-Hold for Pancreatic Cancer

    SciTech Connect

    Nakamura, Mitsuhiro; Shibuya, Keiko; Nakamura, Akira; Shiinoki, Takehiro; Matsuo, Yukinori; Nakata, Manabu; Sawada, Akira; Mizowaki, Takashi; Hiraoka, Masahiro

    2012-04-01

    Purpose: To investigate the interfractional dose variations for intensity-modulated radiotherapy (RT) combined with breath-hold (BH) at end-exhalation (EE) for pancreatic cancer. Methods and Materials: A total of 10 consecutive patients with pancreatic cancer were enrolled. Each patient was fixed in the supine position on an individualized vacuum pillow with both arms raised. Computed tomography (CT) scans were performed before RT, and three additional scans were performed during the course of chemoradiotherapy using a conventional RT technique. The CT data were acquired under EE-BH conditions (BH-CT) using a visual feedback technique. The intensity-modulated RT plan, which used five 15-MV coplanar ports, was designed on the initial BH-CT set with a prescription dose of 39 Gy at 2.6 Gy/fraction. After rigid image registration between the initial and subsequent BH-CT scans, the dose distributions were recalculated on the subsequent BH-CT images under the same conditions as in planning. Changes in the dose-volume metrics of the gross tumor volume (GTV), clinical target volume (CTV = GTV + 5 mm), stomach, and duodenum were evaluated. Results: For the GTV and clinical target volume (CTV), the 95th percentile of the interfractional variations in the maximal dose, mean dose, dose covering 95% volume of the region of structure, and percentage of the volume covered by the 90% isodose line were within {+-}3%. Although the volume covered by the 39 Gy isodose line for the stomach and duodenum did not exceed 0.1 mL at planning, the volume covered by the 39 Gy isodose line for these structures was up to 11.4 cm{sup 3} and 1.8 cm{sup 3}, respectively. Conclusions: Despite variations in the gastrointestinal state and abdominal wall position at EE, the GTV and CTV were mostly ensured at the planned dose, with the exception of 1 patient. Compared with the duodenum, large variations in the stomach volume receiving high-dose radiation were observed, which might be beyond the

  15. A Dosimetric Comparison of Proton and Intensity-Modulated Photon Radiotherapy for Pediatric Parameningeal Rhabdomyosarcomas

    SciTech Connect

    Kozak, Kevin R.; Adams, Judith; Krejcarek, Stephanie J.; Tarbell, Nancy J.; Yock, Torunn I.

    2009-05-01

    Purpose: We compared tumor and normal tissue dosimetry of proton radiation therapy with intensity-modulated radiation therapy (IMRT) for pediatric parameningeal rhabdomyosarcomas (PRMS). Methods and Materials: To quantify dosimetric differences between contemporary proton and photon treatment for pediatric PRMS, proton beam plans were compared with IMRT plans. Ten patients treated with proton radiation therapy at Massachusetts General Hospital had IMRT plans generated. To facilitate dosimetric comparisons, clinical target volumes and normal tissue volumes were held constant. Plans were optimized for target volume coverage and normal tissue sparing. Results: Proton and IMRT plans provided acceptable and comparable target volume coverage, with at least 99% of the CTV receiving 95% of the prescribed dose in all cases. Improved dose conformality provided by proton therapy resulted in significant sparing of all examined normal tissues except for ipsilateral cochlea and mastoid; ipsilateral parotid gland sparing was of borderline statistical significance (p = 0.05). More profound sparing of contralateral structures by protons resulted in greater dose asymmetry between ipsilateral and contralateral retina, optic nerves, cochlea, and mastoids; dose asymmetry between ipsilateral and contralateral parotids was of borderline statistical significance (p = 0.05). Conclusions: For pediatric PRMS, superior normal tissue sparing is achieved with proton radiation therapy compared with IMRT. Because of enhanced conformality, proton plans also demonstrate greater normal tissue dose distribution asymmetry. Longitudinal studies assessing the impact of proton radiotherapy and IMRT on normal tissue function and growth symmetry are necessary to define the clinical consequences of these differences.

  16. Risk of secondary cancers from scattered radiation during intensity-modulated radiotherapies for hepatocellular carcinoma

    PubMed Central

    2014-01-01

    Purpose To evaluate and compare the risks of secondary cancers from therapeutic doses received by patients with hepatocellular carcinoma (HCC) during intensity-modulated radiotherapy (IMRT), volumetric arc therapy (VMAT), and tomotherapy (TOMO). Methods Treatments for five patients with hepatocellular carcinoma (HCC) were planned using IMRT, VMAT, and TOMO. Based on the Biological Effects of Ionizing Radiation VII method, the excess relative risk (ERR), excess absolute risk (EAR), and lifetime attributable risk (LAR) were evaluated from therapeutic doses, which were measured using radiophotoluminescence glass dosimeters (RPLGDs) for each organ inside a humanoid phantom. Results The average organ equivalent doses (OEDs) of 5 patients were measured as 0.23, 1.18, 0.91, 0.95, 0.97, 0.24, and 0.20 Gy for the thyroid, lung, stomach, liver, small intestine, prostate (or ovary), and rectum, respectively. From the OED measurements, LAR incidence were calculated as 83, 46, 22, 30, 2 and 6 per 104 person for the lung, stomach, normal liver, small intestine, prostate (or ovary), and rectum. Conclusions We estimated the secondary cancer risks at various organs for patients with HCC who received different treatment modalities. We found that HCC treatment is associated with a high secondary cancer risk in the lung and stomach. PMID:24886163

  17. Marginal Misses After Postoperative Intensity-Modulated Radiotherapy for Head and Neck Cancer

    SciTech Connect

    Chen, Allen M.; Farwell, D. Gregory; Luu, Quang; Chen, Leon M.; Vijayakumar, Srinivasan; Purdy, James A.

    2011-08-01

    Purpose: To describe the spatial distribution of local-regional recurrence (LRR) among patients treated postoperatively with intensity-modulated radiotherapy (IMRT) for head and neck cancer. Methods and Materials: The medical records of 90 consecutive patients treated by gross total resection and postoperative IMRT for squamous cell carcinoma of the head and neck from January 2003 to July 2009 were reviewed. Sites of disease were the oral cavity (43 patients), oropharynx (20 patients), larynx (15 patients), and hypopharynx (12 patients). Fifty patients (56%) received concurrent chemotherapy. Results: Seventeen of 90 patients treated with postoperative IMRT experienced LRR, yielding a 2-year estimate of local regional control of 80%. Among the LRR patients, 11 patients were classified as in-field recurrences, occurring within the physician-designated clinical target volume, and 6 patients were categorized as marginal recurrences. There were no out-of-field geographical misses. Sites of marginal LRRs included the contralateral neck adjacent to the spared parotid gland (3 patients), the dermal/subcutaneous surface (2 patients), and the retropharyngeal/retrostyloid lymph node region (1 patient). Conclusions: Although the incidence of geographical misses was relatively low, the possibility of this phenomenon should be considered in the design of target volumes among patients treated by postoperative IMRT for head and neck cancer.

  18. Intensity-Modulated Radiotherapy in Postoperative Treatment of Oral Cavity Cancers

    SciTech Connect

    Gomez, Daniel R. Zhung, Joanne E.; Gomez, Jennifer; Chan, Kelvin; Wu, Abraham J.; Wolden, Suzanne L.; Pfister, David G.; Shaha, Ashok; Shah, Jatin P.; Kraus, Dennis H.; Wong, Richard J.; Lee, Nancy Y.

    2009-03-15

    Purpose: To present our single-institution experience of intensity-modulated radiotherapy (IMRT) for oral cavity cancer. Methods and Materials: Between September 2000 and December 2006, 35 patients with histologically confirmed squamous cell carcinoma of the oral cavity underwent surgery followed by postoperative IMRT. The sites included were buccal mucosa in 8, oral tongue in 11, floor of the mouth in 9, gingiva in 4, hard palate in 2, and retromolar trigone in 1. Most patients had Stage III-IV disease (80%). Ten patients (29%) also received concurrent postoperative chemotherapy with IMRT. The median prescribed radiation dose was 60 Gy. Results: The median follow-up for surviving patients was 28.1 months (range, 11.9-85.1). Treatment failure occurred in 11 cases as follows: local in 4, regional in 2, and distant metastases in 5. Of the 5 patients with distant metastases, 2 presented with dermal metastases. The 2- and 3-year estimates of locoregional progression-free survival, distant metastasis-free survival, disease-free survival, and overall survival were 84% and 77%, 85% and 85%, 70% and 64%, and 74% and 74%, respectively. Acute Grade 2 or greater dermatitis, mucositis, and esophageal reactions were experienced by 54%, 66%, and 40% of the patients, respectively. Documented late complications included trismus (17%) and osteoradionecrosis (5%). Conclusion: IMRT as an adjuvant treatment after surgical resection for oral cavity tumors is feasible and effective, with promising results and acceptable toxicity.

  19. Treatment of Nasopharyngeal Carcinoma Using Intensity-Modulated Radiotherapy-The National Cancer Centre Singapore Experience

    SciTech Connect

    Tham, Ivan Weng-Keong; Hee, Siew Wan; Yeo, Richard Ming-Chert; Salleh, Patemah; Lee, James; Tan, Terence Wee-Kiat; Fong, Kam Weng; Chua, Eu Tiong; Wee, Joseph Tien-Seng

    2009-12-01

    Purpose: The aim of this study was to determine the efficacy and acute toxicity of our early experience with treating nasopharyngeal carcinoma (NPC) patients with intensity-modulated radiotherapy (IMRT). Methods and materials: A review was conducted on case records of 195 patients with histologically proven, nonmetastatic NPC treated with IMRT between 2002 and 2005. MRI of the head and neck was fused with CT simulation images. All plans had target volumes at three dose levels, with a prescribed dose of 70 Gy to the gross disease, in 2.0-2.12 Gy/fraction over 33-35 fractions. Cisplatin-based chemotherapy was offered to Stage III/IV patients. Results: Median patient age was 52 years, and 69% were male. Median follow-up was 36.5 months. One hundred and twenty-three patients had Stage III/IV disease (63%); 50 (26%) had T4 disease. One hundred and eighty-eight (96%) had complete response; 7 (4%) had partial response. Of the complete responders, 10 (5.3%) had local recurrence, giving a 3-year local recurrence-free survival estimate of 93.1% and a 3-year disease-free survival of 82.1%. Fifty-one patients (26%) had at least one Grade 3 toxicity. Conclusions: Results from our series are comparable to those reported by other centers. Acute toxicity is common. Local failure or persistent disease, especially in patients with bulky T4 disease, are issues that must be addressed in future trials.

  20. Accuracy of inhomogeneity correction algorithm in intensity-modulated radiotherapy of head-and-neck tumors

    SciTech Connect

    Yoon, Myonggeun; Lee, Doo-Hyun; Shin, Dongho; Lee, Se Byeong; Park, Sung Yong . E-mail: cool_park@ncc.re.kr; Cho, Kwan Ho

    2007-04-01

    We examined the degree of calculated-to-measured dose difference for nasopharyngeal target volume in intensity-modulated radiotherapy (IMRT) based on the observed/expected ratio using patient anatomy with humanoid head-and-neck phantom. The plans were designed with a clinical treatment planning system that uses a measurement-based pencil beam dose-calculation algorithm. Two kinds of IMRT plans, which give a direct indication of the error introduced in routine treatment planning, were categorized and evaluated. The experimental results show that when the beams pass through the oral cavity in anthropomorphic head-and-neck phantom, the average dose difference becomes significant, revealing about 10% dose difference to prescribed dose at isocenter. To investigate both the physical reasons of the dose discrepancy and the inhomogeneity effect, we performed the 10 cases of IMRT quality assurance (QA) with plastic and humanoid phantoms. Our result suggests that the transient electronic disequilibrium with the increased lateral electron range may cause the inaccuracy of dose calculation algorithm, and the effectiveness of the inhomogeneity corrections used in IMRT plans should be evaluated to ensure meaningful quality assurance and delivery.

  1. Risk of second cancer from scattered radiation of intensity-modulated radiotherapies with lung cancer

    PubMed Central

    2013-01-01

    Purpose To compare the risk of secondary cancer from scattered and leakage doses following intensity-modulated radiotherapy (IMRT), volumetric arc therapy (VMAT) and tomotherapy (TOMO) in patients with lung cancer. Methods IMRT, VMAT and TOMO were planned for five lung cancer patients. Organ equivalent doses (OEDs) are estimated from the measured corresponding secondary doses during irradiation at various points 20 to 80 cm from the iso-center by using radio-photoluminescence glass dosimeter (RPLGD). Results The secondary dose per Gy from IMRT, VMAT and TOMO for lung cancer, measured 20 to 80 cm from the iso-center, are 0.02~2.03, 0.03~1.35 and 0.04~0.46 cGy, respectively. The mean values of relative OED of secondary dose of VMAT and TOMO, which is normalized by IMRT, ranged between 88.63% and 41.59% revealing 88.63% and 41.59% for thyroid, 82.33% and 41.85% for pancreas, 77.97% and 49.41% for bowel, 73.42% and 72.55% for rectum, 74.16% and 81.51% for prostate. The secondary dose and OED from TOMO became similar to those from IMRT and VMAT as the distance from the field edge increased. Conclusions OED based estimation suggests that the secondary cancer risk from TOMO is less than or comparable to the risks from conventional IMRT and VMAT. PMID:23452670

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

    PubMed

    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.

  3. Forward-planning intensity-modulated radiotherapy technique for prostate cancer.

    PubMed

    Metwaly, Mohamed; Awaad, Awaad Mousa; El-Sayed, El-Sayed Mahmoud; Sallam, Abdel Sattar Mohamed

    2007-11-05

    In this study, we present an intensity-modulated radiotherapy technique based on forward planning dose calculations to provide a concave dose distribution to the prostate and seminal vesicles by means of modified dynamic arc therapy (M-DAT). Dynamic arcs (350 degrees) conforming to the beam's eye view of the prostate and seminal vesicles while shielding the rectum, combined with two lateral oblique conformal fields (15 degrees with respect to laterals) fitting the prostate only,were applied to deliver doses of 78 Gy and 61.23 Gy in 39 fractions to the prostate and seminal vesicles respectively. Dynamic wedges (45 degrees of thick end, anteriorly oriented) were used with conformal beams to adjust the dose homogeneity to the prostate, although in some cases, hard wedges (30 degrees of thick part,inferiorly oriented) were used with arcs to adjust the dose coverage to the seminal vesicles. The M-DAT was applied to 10 patients in supine and 10 patients in prone positioning to determine the proper patient positioning for optimum protection of the rectum. The M-DAT was compared with the simplified intensity-modulated arc therapy (SIMAT) technique, composed of three phases of bilateral dynamic arcs. The mean rectal dose in M-DAT for prone patients was 22.5 +/- 5.1 Gy; in M-DAT and SIMAT for supine patients, it was 30.2 +/- 5.1 Gy and 39.4 +/- 6.0 Gy respectively. The doses to 15%, 25%, 35%, and 50% of the rectum volume in M-DAT for prone patients were 44.5 +/- 10.2 Gy, 33.0 +/- 8.2 Gy, 25.3 +/- 6.4 Gy, and 16.3 +/- 5.6 Gy respectively. These values were lower than those in M-DAT and in SIMAT for supine patients by 7.7%, 18.2%, 22.4%, and 28.5% and by 25.0%, 32.1%, 34.9%, and 41.9% of the prescribed dose (78 Gy) respectively. Ion chamber measurements showed good agreement of the calculated and measured isocentric dose (maximum deviation of 3.5%). Accuracy of the dose distribution calculation was evaluated by film dosimetry using a gamma index, allowing 3% dose variation and

  4. Simultaneous Integrated Boost Using Intensity-Modulated Radiotherapy Compared With Conventional Radiotherapy in Patients Treated With Concurrent Carboplatin and 5-Fluorouracil for Locally Advanced Oropharyngeal Carcinoma

    SciTech Connect

    Clavel, Sebastien; Nguyen, David H.A.; Fortin, Bernard; Despres, Philippe; Khaouam, Nader; Donath, David; Soulieres, Denis; Guertin, Louis; Nguyen-Tan, Phuc Felix

    2012-02-01

    Purpose: To compare, in a retrospective study, the toxicity and efficacy of simultaneous integrated boost using intensity-modulated radiotherapy (IMRT) vs. conventional radiotherapy (CRT) in patients treated with concomitant carboplatin and 5-fluorouracil for locally advanced oropharyngeal cancer. Methods and Materials: Between January 2000 and December 2007, 249 patients were treated with definitive chemoradiation. One hundred patients had 70 Gy in 33 fractions using IMRT, and 149 received CRT at 70 Gy in 35 fractions. Overall survival, disease-free survival, and locoregional control were estimated using the Kaplan-Meier method. Results: Median follow-up was 42 months. Three-year actuarial rates for locoregional control, disease-free survival, and overall survival were 95.1% vs. 84.4% (p = 0.005), 85.3% vs. 69.3% (p = 0.001), and 92.1% vs. 75.2% (p < 0.001) for IMRT and CRT, respectively. The benefit of the radiotherapy regimen on outcomes was also observed with a Cox multivariate analysis. Intensity-modulated radiotherapy was associated with less acute dermatitis and less xerostomia at 6, 12, 24, and 36 months. Conclusions: This study suggests that simultaneous integrated boost using IMRT is associated with favorable locoregional control and survival rates with less xerostomia and acute dermatitis than CRT when both are given concurrently with chemotherapy.

  5. Flattening Filter-Free Beams in Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy for Sinonasal Cancer

    PubMed Central

    Huang, Bao-Tian

    2016-01-01

    Purpose To evaluate the dosimetric impacts of flattening filter-free (FFF) beams in intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) for sinonasal cancer. Methods For fourteen cases, IMRT and VMAT planning was performed using 6-MV photon beams with both conventional flattened and FFF modes. The four types of plans were compared in terms of target dose homogeneity and conformity, organ-at-risk (OAR) sparing, number of monitor units (MUs) per fraction, treatment time and pure beam-on time. Results FFF beams led to comparable target dose homogeneity, conformity, increased number of MUs and lower doses to the spinal cord, brainstem and normal tissue, compared with flattened beams in both IMRT and VMAT. FFF beams in IMRT resulted in improvements by up to 5.4% for sparing of the contralateral optic structures, with shortened treatment time by 9.5%. However, FFF beams provided comparable overall OAR sparing and treatment time in VMAT. With FFF mode, VMAT yielded inferior homogeneity and superior conformity compared with IMRT, with comparable overall OAR sparing and significantly shorter treatment time. Conclusions Using FFF beams in IMRT and VMAT is feasible for the treatment of sinonasal cancer. Our results suggest that the delivery mode of FFF beams may play an encouraging role with better sparing of contralateral optic OARs and treatment efficiency in IMRT, but yield comparable results in VMAT. PMID:26734731

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

    SciTech Connect

    Lopez Guerra, Jose L.; Gomez, Daniel R.; Zhuang Yan; Levy, Lawrence B.; Eapen, George; Liu, Hongmei; Mohan, Radhe; Komaki, Ritsuko; Cox, James D.; Liao Zhongxing

    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

  7. Intensity-Modulated vs. Conformal Radiotherapy of Parotid Gland Tumors: Potential Impact on Hearing Loss

    SciTech Connect

    Lamers-Kuijper, E. Schwarz, M.; Rasch, C.; Mijnheer, B.

    2007-01-01

    In 3-dimensional (3D) conformal radiotherapy of parotid gland tumors, little effort is made to avoid the auditory system or the oral cavity. Damage may occur when the ear is located inside the treatment field. The purpose of this study was to design and evaluate an intensity-modulation radiotherapy (IMRT) class solution, and to compare this technique to a 3D conformal approach with respect to hearing loss. Twenty patients with parotid gland cancer were retrospectively planned with 2 different techniques using the original planning target volume (PTV). First, a conventional technique using a wedged beam pair was applied, yielding a dose distribution conformal to the shape of the PTV. Next, an IMRT technique using a fluence map optimization with predefined constraints was designed. A dose of 66 Gy in the PTV was given at the International Commission on Radiation Units and Measures (ICRU) dose prescription point. Dose-volume histograms of the PTV and organs at risk (OARs), such as auditory system, oral cavity, and spinal cord, were compared. The dose in the OARs was lower in the IMRT plans. The mean volume of the middle ear receiving a dose higher than 50 Gy decreased from 66.5% to 33.4%. The mean dose in the oral cavity decreased from 19.4 Gy to 16.6 Gy. The auditory system can be spared if the distance between the inner ear and the PTV is 0.6 cm or larger, and if the overlap between the middle ear and the PTV is smaller than 10%. The maximum dose in the spinal cord was below 40 Gy in all treatment plans. The mean volume of the PTV receiving less than 95% of the prescribed dose increased in the IMRT plan slightly from 3.3% to 4.3 % (p = 0.01). The mean volume receiving more than 107% increased from 0.9% to 2.5% (p = 0.02). It can be concluded that the auditory system, as well as the oral cavity, can be spared with IMRT, but at the cost of a slightly larger dose inhomogeneity in the PTV. The IMRT technique can therefore, in most cases, be recommended as the treatment

  8. Intensity modulated radiotherapy in early stage Hodgkin lymphoma patients: Is it better than three dimensional conformal radiotherapy?

    PubMed Central

    2012-01-01

    Background Cure rate of early Hodgkin Lymphoma are high and avoidance of late toxicities is of paramount importance. This comparative study aims to assess the normal tissue sparing capability of intensity-modulated radiation therapy (IMRT) versus standard three-dimensional conformal radiotherapy (3D-CRT) in terms of dose-volume parameters and normal tissue complication probability (NTCP) for different organs at risk in supradiaphragmatic Hodgkin Lymphoma (HL) patients. Methods Ten HL patients were actually treated with 3D-CRT and all treatments were then re-planned with IMRT. Dose-volume parameters for thyroid, oesophagus, heart, coronary arteries, lung, spinal cord and breast were evaluated. Dose-volume histograms generated by TPS were analyzed to predict the NTCP for the considered organs at risk, according to different endpoints. Results Regarding dose-volume parameters no statistically significant differences were recorded for heart and origin of coronary arteries. We recorded statistically significant lower V30 with IMRT for oesophagus (6.42 vs 0.33, p = 0.02) and lungs (4.7 vs 0.1 p = 0.014 for the left lung and 2.59 vs 0.1 p = 0.017 for the right lung) and lower V20 for spinal cord (17.8 vs 7.2 p = 0.02). Moreover the maximum dose to the spinal cord was lower with IMRT (30.2 vs 19.9, p <0.001). Higher V10 with IMRT for thyroid (64.8 vs 95, p = 0.0019) and V5 for lungs (30.3 vs 44.8, p = 0.03, for right lung and 28.9 vs 48.1, p = 0.001 for left lung) were found, respectively. Higher V5 and V10 for breasts were found with IMRT (V5: 4.14 vs 20.6, p = 0.018 for left breast and 3.3 vs 17, p = 0.059 for right breast; V10: 2.5 vs 13.6 p = 0.035 for left breast and 1.7 vs 11, p = 0.07 for the right breast.) As for the NTCP, our data point out that IMRT is not always likely to significantly increase the NTCP to OARs. Conclusions In HL male patients IMRT seems feasible and accurate while for women HL patients IMRT should be

  9. Comparative analysis of SmartArc-based dual arc volumetric-modulated arc radiotherapy (VMAT) versus intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma.

    PubMed

    Lee, Tsair-Fwu; Chao, Pei-Ju; Ting, Hui-Min; Lo, Su-Hua; Wang, Yu-Wen; Tuan, Chiu-Ching; Fang, Fu-Min; Su, Te-Jen

    2011-11-15

    The purpose of this study was to evaluate and quantify the planning performance of SmartArc-based volumetric-modulated arc radiotherapy (VMAT) versus fixed-beam intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC) using a sequential mode treatment plan. The plan quality and performance of dual arc-VMAT (DA-VMAT) using the Pinnacle3 Smart-Arc system (clinical version 9.0; Philips, Fitchburg, WI, USA) were evaluated and compared with those of seven-field (7F)-IMRT in 18 consecutive NPC patients. Analysis parameters included the conformity index (CI) and homogeneity index (HI) for the planning target volume (PTV), maximum and mean dose, normal tissue complication probability (NTCP) for the specified organs at risk (OARs), and comprehensive quality index (CQI) for an overall evaluation in the 11 OARs. Treatment delivery time, monitor units per fraction (MU/fr), and Gamma(3 mm, 3%) evaluations were also analyzed. DA-VMAT achieved similar target coverage and slightly better homogeneity than conventional 7F-IMRT with a similar CI and HI. NTCP values were only significantly lower in the left parotid gland (for xerostomia) for DA-VMAT plans. The mean value of CQI at 0.98 ± 0.02 indicated a 2% benefit in sparing OARs by DA-VMAT. The MU/fr used and average delivery times appeared to show improved efficiencies in DA-VMAT. Each technique demonstrated high accuracy in dose delivery in terms of a high-quality assurance (QA) passing rate (> 98%) of the Gamma(3 mm, 3%) criterion. The major difference between DA-VMAT and 7F-IMRT using a sequential mode for treating NPC cases appears to be improved efficiency, resulting in a faster delivery time and the use of fewer MU/fr.

  10. Is Planned Neck Dissection Necessary for Head and Neck Cancer After Intensity-Modulated Radiotherapy?

    SciTech Connect

    Yao Min |. E-mail: min-yao@uiowa.edu; Hoffman, Henry T.; Funk, Gerry F. |; Chang, Kristi; Smith, Russell B. |; Tan Huaming; Clamon, Gerald H.; Dornfeld, Ken |; Buatti, John M. |

    2007-07-01

    Purpose: The objective of this study was to determine regional control of local regional advanced head and neck squamous cell carcinoma (HNSCC) treated with intensity-modulated radiotherapy (IMRT), along with the role and selection criteria for neck dissection after IMRT. Methods and Materials: A total of 90 patients with stage N2A or greater HNSCC were treated with definitive IMRT from December 1999 to July 2005. Three clinical target volumes were defined and were treated to 70 to 74 Gy, 60 Gy, and 54 Gy, respectively. Neck dissection was performed for selected patients after IMRT. Selection criteria evolved during this period with emphasis on post-IMRT [{sup 18}F] fluorodeoxyglucose positron emission tomography in recent years. Results: Median follow-up for all patients was 29 months (range, 0.2-74 months). All living patients were followed at least 9 months after completing treatment. Thirteen patients underwent neck dissection after IMRT because of residual lymphadenopathy. Of these, 6 contained residual viable tumor. Three patients with persistent adenopathy did not undergo neck dissection: 2 refused and 1 had lung metastasis. Among the remaining 74 patients who were observed without neck dissection, there was only 1 case of regional failure. Among all 90 patients in this study, the 3-year local and regional control was 96.3% and 95.4%, respectively. Conclusions: Appropriately delivered IMRT has excellent dose coverage for cervical lymph nodes. A high radiation dose can be safely delivered to the abnormal lymph nodes. There is a high complete response rate. Routine planned neck dissection for patients with N2A and higher stage after IMRT is not necessary. Post-IMRT [{sup 18}F] fluorodeoxyglucose positron emission tomography is a useful tool in selecting patients appropriate for neck dissection.

  11. Changes Mimicking New Leptomeningeal Disease After Intensity-Modulated Radiotherapy for Medulloblastoma

    SciTech Connect

    Muscal, Jodi A.; Jones, Jeremy Y.; Paulino, Arnold C.; Bertuch, Alison A.; Su, Jack; Woo, Shiao Y.; Mahoney, Donald H.; Chintagumpala, Murali

    2009-01-01

    Purpose: Acute and late changes in magnetic resonance imaging of the pediatric brain have been described after radiotherapy (RT). We report the post-RT neuroimaging changes in the posterior fossa after intensity-modulated RT (IMRT) in children with medulloblastoma and contrast them with those of leptomeningeal disease. Methods and Materials: We performed a retrospective review of 53 consecutive children with medulloblastoma who were treated with craniospinal RT followed by IMRT to the posterior fossa and chemotherapy between 1997 and 2006. Results: After IMRT to the posterior fossa, 8 (15%) of 53 patients developed increased fluid-attenuated inversion-recovery signal changes in the brainstem or cerebellum and patchy, multifocal, nodular contrast enhancement at a median of 6 months. The enhancement superficially resembled leptomeningeal disease. However, the enhancement resolved without intervention at a median of 6 months later. The accompanying fluid-attenuated inversion-recovery signal changes occasionally preceded the enhancement, were often parenchymal in location, and resolved or persisted to a lesser degree. All 8 patients with transient magnetic resonance imaging changes in the posterior fossa were alive at last follow-up. In contrast, leptomeningeal disease occurred in 8 (15%) of our 53 patients at a median of 19.5 months after IMRT completion. Of these 8 patients, 7 demonstrated initial nodular enhancement outside the conformal field, and 7 patients died. Conclusion: Magnetic resonance imaging changes can occur in the posterior fossa of children treated with IMRT for medulloblastoma. In our experience, these transient changes occur at a characteristic time and location after RT, allowing them to be distinguished from leptomeningeal disease.

  12. Prognostic Value of Prevertebral Space Involvement in Nasopharyngeal Carcinoma Based on Intensity-Modulated Radiotherapy

    SciTech Connect

    Zhou Guanqun; Mao YanPing; Chen Lei; Li Wenfei; Liu Lizhi; Sun Ying; Chen Yong; Tian Li; Lin Aihua; Li Li; and others

    2012-03-01

    Purpose: To investigate the prognostic significance of prevertebral space involvement (PSI) in patients with nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT). Methods and Materials: A retrospective review of data from 506 biopsy-proven, nonmetastatic NPCs was performed. Patients underwent magnetic resonance imaging examinations and received IMRT as their primary treatment. Results: In this series, 161 NPC patients (31.8%) had PSI. Parapharyngeal space (p < 0.001), skull base (p < 0.001), and paranasal sinuses (p = 0.009) were associated with PSI after multivariate analysis. The 4-year overall survival (OS), local relapse-free survival (LRFS), distant metastasis-free survival (DMFS) for NPC patients with and without PSI was 69.1% and 89.2% (p < 0.0001), 83.9% and 96.4% (p < 0.0001), and 71.6% and 89.6% (p < 0.0001), respectively. Multivariate analysis identified PSI as an independent negative prognostic factor for both OS (HR = 1.478-4.380; p = 0.001) and DMFS (HR = 1.389-4.174; p = 0.002). Patients with PSI had similar survival rates in OS and DMFS (p = 0.241 and p = 0.493, respectively) to that of T4 disease, while the differences between PSI and T3 disease in both OS and DMFS were distinctly significant (p = 0.029 and p = 0.029, respectively). Conclusions: For NPC patients treated with IMRT, PSI was found to be an independent prognostic factor for both OS and DMFS. It seems reasonable that PSI should be classified as a T4 disease on the basis of the current American Joint Committee on Cancer staging classification criteria.

  13. Carotid sparing intensity modulated radiotherapy on early glottic cancer: preliminary study

    PubMed Central

    Choi, Hoon Sik; Jeong, Bae Kwon; Jeong, Hojin; Song, Jin Ho; Kim, Jin Pyeong; Park, Jung Je; Woo, Seung Hoon

    2016-01-01

    Purpose 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. Materials and Methods 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. Results 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). Conclusion 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. PMID:27104164

  14. Automated Planning of Tangential Breast Intensity-Modulated Radiotherapy Using Heuristic Optimization

    SciTech Connect

    Purdie, Thomas G.; Dinniwell, Robert E.; Letourneau, Daniel; Hill, Christine; Sharpe, Michael B.

    2011-10-01

    Purpose: To present an automated technique for two-field tangential breast intensity-modulated radiotherapy (IMRT) treatment planning. Method and Materials: A total of 158 planned patients with Stage 0, I, and II breast cancer treated using whole-breast IMRT were retrospectively replanned using automated treatment planning tools. The tools developed are integrated into the existing clinical treatment planning system (Pinnacle{sup 3}) and are designed to perform the manual volume delineation, beam placement, and IMRT treatment planning steps carried out by the treatment planning radiation therapist. The automated algorithm, using only the radio-opaque markers placed at CT simulation as inputs, optimizes the tangential beam parameters to geometrically minimize the amount of lung and heart treated while covering the whole-breast volume. The IMRT parameters are optimized according to the automatically delineated whole-breast volume. Results: The mean time to generate a complete treatment plan was 6 min, 50 s {+-} 1 min 12 s. For the automated plans, 157 of 158 plans (99%) were deemed clinically acceptable, and 138 of 158 plans (87%) were deemed clinically improved or equal to the corresponding clinical plan when reviewed in a randomized, double-blinded study by one experienced breast radiation oncologist. In addition, overall the automated plans were dosimetrically equivalent to the clinical plans when scored for target coverage and lung and heart doses. Conclusion: We have developed robust and efficient automated tools for fully inversed planned tangential breast IMRT planning that can be readily integrated into clinical practice. The tools produce clinically acceptable plans using only the common anatomic landmarks from the CT simulation process as an input. We anticipate the tools will improve patient access to high-quality IMRT treatment by simplifying the planning process and will reduce the effort and cost of incorporating more advanced planning into clinical

  15. Regional Relapse After Intensity-Modulated Radiotherapy for Head-and-Neck Cancer

    SciTech Connect

    Duprez, Frederic; Bonte, Katrien; De Neve, Wilfried; Boterberg, Tom; De Gersem, Werner; Madani, Indira

    2011-02-01

    Purpose: To evaluate the regional relapse rate in the elective neck using intensity-modulated radiotherapy (IMRT) for head-and-neck cancer. Methods and Materials: We retrospectively analyzed the data from 285 patients treated with IMRT between 2000 and 2008. The median dose prescription to the primary tumor and involved lymph nodes was 69 Gy in 32 fractions. The elective neck was treated simultaneously according to Protocol 1 (multiple dose prescription levels of 56-69 Gy; 2-Gy normalized isoeffective dose, 51-70 Gy; 222 patients) or Protocol 2 (one dose prescription level of 56 Gy; 2-Gy normalized isoeffective dose, 51 Gy; 63 patients). Primary surgery or lymph node dissection was performed before IMRT in 72 (25%) and 157 (55%) patients, respectively. Also, 92 patients (32%) received concomitant chemotherapy. The median follow-up of living patients was 27.4 months (range, 0.3-99). Results: Regional, local, and distant relapse were observed in 16 (5.6%), 35 (12.3%), and 47 (16.5%) patients, respectively. The 2- and 5-year rate of regional relapse was 7% and 10%, respectively, with a trend favoring Protocol 2 (p = 0.06). Seven isolated regional relapses were detected at a median follow-up of 7.3 months in patients treated with Protocol 1 and none in those treated with Protocol 2. Percutaneous gastrostomy was required more frequently in patients who received Protocol 1 (p = 0.079). Conclusion: Isolated regional relapse is rare after IMRT for head-and-neck cancer. Elective neck node doses >51 Gy for a 2-Gy normalized isoeffective dose do not seem to improve regional control.

  16. Candidate Dosimetric Predictors of Long-Term Swallowing Dysfunction After Oropharyngeal Intensity-Modulated Radiotherapy

    SciTech Connect

    Schwartz, David L.; Hutcheson, Katherine; Barringer, Denise; Tucker, Susan L.; Kies, Merrill; Ang, K. Kian; Morrison, William H.; Rosenthal, David I.; Garden, Adam S.; Dong Lei; Lewin, Jan S.

    2010-12-01

    Purpose: To investigate long-term swallowing function in oropharyngeal cancer patients treated with intensity-modulated radiotherapy (IMRT), and to identify novel dose-limiting criteria predictive for dysphagia. Methods and Materials: Thirty-one patients with Stage IV oropharyngeal squamous carcinoma enrolled on a Phase II trial were prospectively evaluated by modified barium swallow studies at baseline, and 6, 12, and 24 months post-IMRT treatment. Candidate dysphagia-associated organs at risk were retrospectively contoured into original treatment plans. Twenty-one (68%) cases were base of tongue and 10 (32%) were tonsil. Stage distribution was T1 (12 patients), T2 (10), T3 (4), T4 (2), and TX (3), and N2 (24), N3 (5), and NX (2). Median age was 52.8 years (range, 42-78 years). Thirteen patients (42%) received concurrent chemotherapy during IMRT. Thirteen (42%) were former smokers. Mean dose to glottic larynx for the cohort was limited to 18 Gy (range, 6-39 Gy) by matching IMRT to conventional low-neck fields. Results: Dose-volume constraints (V30 < 65% and V35 < 35% for anterior oral cavity and V55 < 80% and V65 < 30% for high superior pharyngeal constrictors) predictive for objective swallowing dysfunction were identified by univariate and multivariate analyses. Aspiration and feeding tube dependence were observed in only 1 patient at 24 months. Conclusions: In the context of glottic laryngeal shielding, we describe candidate oral cavity and superior pharyngeal constrictor organs at risk and dose-volume constraints associated with preserved long-term swallowing function; these constraints are currently undergoing prospective validation. Strict protection of the glottic larynx via beam-split IMRT techniques promises to make chronic aspiration an uncommon outcome.

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

    SciTech Connect

    Bekelman, Justin E.; Mitra, Nandita; Efstathiou, Jason; Liao Kaijun; Sunderland, Robert; Yeboa, Deborah N.; Armstrong, Katrina

    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.

  18. Intensity-Modulated Radiotherapy in the Treatment of Oropharyngeal Cancer: Clinical Outcomes and Patterns of Failure

    SciTech Connect

    Daly, Megan E.; Le, Quynh-Thu; Maxim, Peter G.; Loo, Billy W.; Kaplan, Michael J.; Fischbein, Nancy J.; Pinto, Harlan; Chang, Daniel T.

    2010-04-15

    Purpose: To report outcomes, failures, and toxicities in patients treated with intensity-modulated radiotherapy (IMRT) for squamous cell carcinoma of the oropharynx. Methods And Materials: Between Aug 2001 and Oct 2007, 107 patients were treated with IMRT with curative intent at Stanford University. Twenty-two patients were treated postoperatively, and 85 were treated definitively. Concurrent platinum-based chemotherapy was administered to 86 patients (80%) and cetuximab to 8 patients (7%). The prescribed dose was 66 Gy at 2.2 Gy/fraction for definitively treated cases and 60 Gy at 2 Gy/fraction for postoperative cases. Median follow-up was 29 months among surviving patients (range, 4-105 months). Results: Eight patients had persistent disease or local-regional failure at a median of 6.5 months (range, 0-9.9 months). Six local failures occurred entirely within the high-risk clinical target volume (CTV) (one with simultaneous distant metastasis). One patient relapsed within the high- and intermediate-risk CTV. One patient had a recurrence at the junction between the IMRT and low-neck fields. Seven patients developed distant metastasis as the first site of failure. The 3-year local-regional control (LRC), freedom from distant metastasis, overall survival, and disease-free survival rates were 92%, 92%, 83%, and 81%, respectively. T stage (T4 vs. T1-T3) was predictive of poorer LRC (p = 0.001), overall survival (p = 0.001), and disease-free survival (p < 0.001) rates. Acute toxicity consisted of 58% grade 3 mucosal and 5% grade 3 skin reactions. Six patients (6%) developed grade >=3 late complications. Conclusions: IMRT provides excellent LRC for oropharyngeal squamous cell carcinoma. Distant metastases are a major failure pattern. No marginal failures were observed.

  19. Clinical Outcome and Prognostic Factors of Intensity-Modulated Radiotherapy for T4 Stage Nasopharyngeal Carcinoma

    PubMed Central

    Luo, Yangkun; Gao, Yang; Yang, Guangquan; Lang, Jinyi

    2016-01-01

    Objective. To analyze the clinical outcomes and prognostic factors of intensity-modulated radiotherapy (IMRT) for T4 stage nasopharyngeal carcinoma (NPC). Methods. Between March 2005 and March 2010, 110 patients with T4 stage NPC without distant metastases were treated. All patients received IMRT. Induction and/or concurrent chemotherapy were given. 47 (42.7%) patients received IMRT replanning. Results. The 5-year local recurrence-free survival (LRFS), regional recurrence-free survival (RRFS), distant metastasis-free survival (DMFS), progression-free survival (PFS), and overall survival (OS) rates were 90.1%, 97.0%, 67.5%, 63.9%, and 64.5%, respectively. Eleven patients experienced local-regional failure and total distant metastasis occurred in 34 patients. 45 patients died and 26 patients died of distant metastasis alone. The 5-year LRFS rates were 97.7% and 83.8% for the patients that received and did not receive IMRT replanning, respectively (P = 0.023). Metastasis to the retropharyngeal lymph nodes (RLN) was associated with inferior 5-year OS rate (61.0% versus 91.7%, P = 0.034). The gross tumor volume of the right/left lymph nodes (GTVln) was an independent prognostic factor for DMFS (P = 0.006) and PFS (P = 0.018). GTVln was with marginal significance as the prognostic factor for OS (P = 0.050). Conclusion. IMRT provides excellent local-regional control for T4 stage NPC. Benefit of IMRT replanning may be associated with improvement in local control. Incorporating GTVln into the N staging system may provide better prognostic information. PMID:27195286

  20. Intensity-Modulated Radiotherapy for Sinonasal Tumors: Ghent University Hospital Update

    SciTech Connect

    Madani, Indira Bonte, Katrien; Vakaet, Luc; Boterberg, Tom; Neve, Wilfried de

    2009-02-01

    Purpose: To report the long-term outcome of intensity-modulated radiotherapy (IMRT) for sinonasal tumors. Methods and Materials: Between July 1998 and November 2006, 84 patients with sinonasal tumors were treated with IMRT to a median dose of 70 Gy in 35 fractions. Of the 84 patients, 73 had a primary tumor and 11 had local recurrence. The tumor histologic type was adenocarcinoma in 54, squamous cell carcinoma in 17, esthesioneuroblastoma in 9, and adenoid cystic carcinoma in 4. The tumors were located in the ethmoid sinus in 47, maxillary sinus in 19, nasal cavity in 16, and multiple sites in 2. Postoperative IMRT was performed in 75 patients and 9 patients received primary IMRT. Results: The median follow-up of living patients was 40 months (range, 8-106). The 5-year local control, overall survival, disease-specific survival, disease-free survival, and freedom from distant metastasis rate was 70.7%, 58.5%, 67%, 59.3%, and 82.2%, respectively. No difference was found in local control and survival between patients with primary or recurrent tumors. On multivariate analysis, invasion of the cribriform plate was significantly associated with lower local control (p = 0.0001) and overall survival (p = 0.0001). Local and distant recurrence was detected in 19 and 10 patients, respectively. Radiation-induced blindness was not observed. One patient developed Grade 3 radiation-induced retinopathy and neovascular glaucoma. Nonocular late radiation-induced toxicity comprised complete lacrimal duct stenosis in 1 patient and brain necrosis in 3 patients. Osteoradionecrosis of the maxilla and brain necrosis were detected in 1 of the 5 reirradiated patients. Conclusion: IMRT for sinonasal tumors provides low rates of radiation-induced toxicity without blindness with high local control and survival. IMRT could be considered as the treatment of choi0008.

  1. A Multiplan Treatment-Planning Framework: A Paradigm Shift for Intensity-Modulated Radiotherapy

    SciTech Connect

    Meyer, Robert R.; Zhang, Hao H.; Goadrich, Laura; Nazareth, Daryl P.; Shi Leyuan; D'Souza, Warren D. . E-mail: wdsou001@umaryland.edu

    2007-07-15

    Purpose: To describe a multiplan intensity-modulated radiotherapy (IMRT) planning framework, and to describe a decision support system (DSS) for ranking multiple plans and modeling the planning surface. Methods and Materials: One hundred twenty-five plans were generated sequentially for a head-and-neck case and a pelvic case by varying the dose-volume constraints on each of the organs at risk (OARs). A DSS was used to rank plans according to dose-volume histogram (DVH) values, as well as equivalent uniform dose (EUD) values. Two methods for ranking treatment plans were evaluated: composite criteria and pre-emptive selection. The planning surface determined by the results was modeled using quadratic functions. Results: The DSS provided an easy-to-use interface for the comparison of multiple plan features. Plan ranking resulted in the identification of one to three 'optimal' plans. The planning surface models had good predictive capability with respect to both DVH values and EUD values and generally, errors of <6%. Models generated by minimizing the maximum relative error had significantly lower relative errors than models obtained by minimizing the sum of squared errors. Using the quadratic model, plan properties for one OAR were determined as a function of the other OAR constraint settings. The modeled plan surface can then be used to understand the interdependence of competing planning objectives. Conclusion: The DSS can be used to aid the planner in the selection of the most desirable plan. The collection of quadratic models constructed from the plan data to predict DVH and EUD values generally showed excellent agreement with the actual plan values.

  2. Concurrent Chemotherapy and Intensity-Modulated Radiotherapy for Locoregionally Advanced Laryngeal and Hypopharyngeal Cancers

    SciTech Connect

    Lee, Nancy Y. O'Meara, William; Chan, Kelvin; Della-Bianca, Cesar; Mechalakos, James G.; Zhung, Joanne; Wolden, Suzanne L.; Narayana, Ashwatha; Kraus, Dennis; Shah, Jatin P.; Pfister, David G.

    2007-10-01

    Purpose: To perform a retrospective review of laryngeal/hypopharyngeal carcinomas treated with concurrent chemotherapy and intensity-modulated radiotherapy (IMRT). Methods and Materials: Between January 2002 and June 2005, 20 laryngeal and 11 hypopharyngeal carcinoma patients underwent IMRT with concurrent platinum-based chemotherapy; most patients had Stage IV disease. The prescription of the planning target volume for gross, high-risk, and low-risk subclinical disease was 70, 59.4, and 54 Gy, respectively. Acute/late toxicities were retrospectively scored using the Common Toxicity Criteria scale. The 2-year local progression-free, regional progression-free, laryngectomy-free, distant metastasis-free, and overall survival rates were calculated using the Kaplan-Meier method. Results: The median follow-up of the living patients was 26 months (range, 17-58 months). The 2-year local progression-free, regional progression-free, laryngectomy-free, distant metastasis-free, and overall survival rate was 86%, 94%, 89%, 92%, and 63%, respectively. Grade 2 mucositis or higher occurred in 48% of patients, and all experienced Grade 2 or higher pharyngitis during treatment. Xerostomia continued to decrease over time from the end of RT, with none complaining of Grade 2 toxicity at this analysis. The 2-year post-treatment percutaneous endoscopic gastrostomy-dependency rate for those with hypopharyngeal and laryngeal tumors was 31% and 15%, respectively. The most severe late complications were laryngeal necrosis, necrotizing fascitis, and a carotid rupture resulting in death 3 weeks after salvage laryngectomy. Conclusion: These preliminary results have shown that IMRT achieved encouraging locoregional control of locoregionally advanced laryngeal and hypopharyngeal carcinomas. Xerostomia improved over time. Pharyngoesophageal stricture with percutaneous endoscopic gastrostomy dependency remains a problem, particularly for patients with hypopharyngeal carcinoma and, to a lesser

  3. Intensity modulated radiation therapy or stereotactic fractionated radiotherapy for infratentorial ependymoma in children: a multicentric study.

    PubMed

    Weber, Damien C; Zilli, Thomas; Do, Hans Peter; Nouet, Philippe; Gumy Pause, Fabienne; Pause, Fabienne Gumy; Pica, Alessia

    2011-04-01

    This study was to evaluate the treatment dosimetry, efficacy and toxicity of intensity modulated radiation therapy (IMRT) and fractionated stereotactic radiotherapy (FSRT) in the management of infratentorial ependymoma. Between 1999 and 2007, seven children (median age, 3.1 years) with infratentorial ependymoma were planned with either IMRT (3 patients) or SFRT (4 patients), the latter after conventional posterior fossa irradiation. Two children underwent gross total resection. Median prescribed dose was 59.4 Gy (range, 55.8-60). The median follow-up for surviving patients was 4.8 years (range, 1.3-8). IMRT (median dose, 59.4 Gy) and FSRT (median dose, 55.8 Gy) achieved similar optimal target coverage. Percentages of maximum doses delivered to the cochleae (59.5 vs 85.0% Gy; P = 0.05) were significantly inferior with IMRT, when compared to FSRT planning. Percentages of maximum doses administered to the pituitary gland (38.2 vs 20.1%; P = 0.05) and optic chiasm (38.1 vs 14.1%; P = 0.001) were, however, significantly higher with IMRT, when compared to FSRT planning. No recurrences were observed at the last follow-up. The estimated 3-year progression-free survival and overall survival were 87.5 and 100%, respectively. No grade >1 acute toxicity was observed. Two patients presented late adverse events (grade 2 hypoacousia) during follow-up, without cognitive impairment. IMRT or FSRT for infratentorial ependymomas is effective and associated with a tolerable toxicity level. Both treatment techniques were able to capitalize their intrinsic conformal ability to deliver high-dose radiation. Larger series of patients treated with these two modalities will be necessary to more fully evaluate these delivery techniques.

  4. Intensity modulation with respiratory gating for radiotherapy of the pleural space

    SciTech Connect

    Ahmed, Raef S.; Shen, Sui; Ove, Roger; Duan, Jun; Fiveash, John B.; Russo, Suzanne M. . E-mail: suzrusso@msn.com

    2007-04-01

    We wanted to describe a technique for the implementation of intensity-modulated radiotherapy (IMRT) with a real-time position monitor (RPM) respiratory gating system for the treatment of pleural space with intact lung. The technique is illustrated by a case of pediatric osteosarcoma, metastatic to the pleura of the right lung. The patient was simulated in the supine position where a breathing tracer and computed tomography (CT) scans synchronized at end expiration were acquired using the RPM system. The gated CT images were used to define target volumes and critical structures. Right pleural gated IMRT delivered at end expiration was prescribed to a dose of 44 Gy, with 55 Gy delivered to areas of higher risk via simultaneous integrated boost (SIB) technique. IMRT was necessary to avoid exceeding the tolerance of intact lung. Although very good coverage of the target volume was achieved with a shell-shaped dose distribution, dose over the targets was relatively inhomogeneous. Portions of target volumes necessarily intruded into the right lung, the liver, and right kidney, limiting the degree of normal tissue sparing that could be achieved. The radiation doses to critical structures were acceptable and well tolerated. With intact lung, delivering a relatively high dose to the pleura with acceptable doses to surrounding normal tissues using respiratory gated pleural IMRT is feasible. Treatment delivery during a limited part of the respiratory cycle allows for reduced CT target volume motion errors, with reduction in the portion of the planning margin that accounts for respiratory motion, and subsequent increase in the therapeutic ratio.

  5. Transitioning from conventional radiotherapy to intensity-modulated radiotherapy for localized prostate cancer: changing focus from rectal bleeding to detailed quality of life analysis.

    PubMed

    Yamazaki, Hideya; Nakamura, Satoaki; Nishimura, Takuya; Yoshida, Ken; Yoshioka, Yasuo; Koizumi, Masahiko; Ogawa, Kazuhiko

    2014-11-01

    With the advent of modern radiation techniques, we have been able to deliver a higher prescribed radiotherapy dose for localized prostate cancer without severe adverse reactions. We reviewed and analyzed the change of toxicity profiles of external beam radiation therapy (EBRT) from the literature. Late rectal bleeding is the main adverse effect, and an incidence of >20% of Grade ≥2 adverse events was reported for 2D conventional radiotherapy of up to 70 Gy. 3D conformal radiation therapy (3D-CRT) was found to reduce the incidence to ∼10%. Furthermore, intensity-modulated radiation therapy (IMRT) reduced it further to a few percentage points. However, simultaneously, urological toxicities were enhanced by dose escalation using highly precise external radiotherapy. We should pay more attention to detailed quality of life (QOL) analysis, not only with respect to rectal bleeding but also other specific symptoms (such as urinary incontinence and impotence), for two reasons: (i) because of the increasing number of patients aged >80 years, and (ii) because of improved survival with elevated doses of radiotherapy and/or hormonal therapy; age is an important prognostic factor not only for prostate-specific antigen (PSA) control but also for adverse reactions. Those factors shift the main focus of treatment purpose from survival and avoidance of PSA failure to maintaining good QOL, particularly in older patients. In conclusion, the focus of toxicity analysis after radiotherapy for prostate cancer patients is changing from rectal bleeding to total elaborate quality of life assessment. PMID:25204643

  6. Transitioning from conventional radiotherapy to intensity-modulated radiotherapy for localized prostate cancer: changing focus from rectal bleeding to detailed quality of life analysis

    PubMed Central

    Yamazaki, Hideya; Nakamura, Satoaki; Nishimura, Takuya; Yoshida, Ken; Yoshioka, Yasuo; Koizumi, Masahiko; Ogawa, Kazuhiko

    2014-01-01

    With the advent of modern radiation techniques, we have been able to deliver a higher prescribed radiotherapy dose for localized prostate cancer without severe adverse reactions. We reviewed and analyzed the change of toxicity profiles of external beam radiation therapy (EBRT) from the literature. Late rectal bleeding is the main adverse effect, and an incidence of >20% of Grade ≥2 adverse events was reported for 2D conventional radiotherapy of up to 70 Gy. 3D conformal radiation therapy (3D-CRT) was found to reduce the incidence to ∼10%. Furthermore, intensity-modulated radiation therapy (IMRT) reduced it further to a few percentage points. However, simultaneously, urological toxicities were enhanced by dose escalation using highly precise external radiotherapy. We should pay more attention to detailed quality of life (QOL) analysis, not only with respect to rectal bleeding but also other specific symptoms (such as urinary incontinence and impotence), for two reasons: (i) because of the increasing number of patients aged >80 years, and (ii) because of improved survival with elevated doses of radiotherapy and/or hormonal therapy; age is an important prognostic factor not only for prostate-specific antigen (PSA) control but also for adverse reactions. Those factors shift the main focus of treatment purpose from survival and avoidance of PSA failure to maintaining good QOL, particularly in older patients. In conclusion, the focus of toxicity analysis after radiotherapy for prostate cancer patients is changing from rectal bleeding to total elaborate quality of life assessment. PMID:25204643

  7. Image-Guided Intensity-Modulated Photon Radiotherapy Using Multifractionated Regimen to Paraspinal Chordomas and Rare Sarcomas

    SciTech Connect

    Terezakis, Stephanie A. Lovelock, D. Michael; Bilsky, Mark H.; Hunt, Margaret A.; Zatcky, Joan N.P.; Yamada, Yoshiya

    2007-12-01

    Purpose: Image-guided intensity-modulated radiotherapy enables delivery of high-dose radiation to tumors close to the spinal cord. We report our experience with multifractionated regimens using image-guided intensity-modulated radiotherapy to treat gross paraspinal disease to doses beyond cord tolerance. Methods and Materials: We performed a retrospective review of 27 consecutive patients with partially resected or unresectable paraspinal tumors irradiated to >5,300 cGy in standard fractionation. Results: The median follow-up was 17.4 months (range, 2.1-47.3). Eighteen sarcomas, seven chordomas, and two ependymomas were treated. The median dose to the planning target volume was 6,600 cGy (range, 5,396-7,080) in 180- or 200-cGy fractions. The median planning target volume was 164 cm{sup 3} (range, 29-1,116). Seven patients developed recurrence at the treatment site (26%), and 6 of these patients had high-grade tumors. Three patients with recurrence had metastatic disease at the time of radiotherapy. The 2-year local control rate was 65%, and the 2-year overall survival rate was 79%. Of the 5 patients who died, 4 had metastatic disease at death. Twenty-three patients (84%) reported either no pain or improved pain at the last follow-up visit. Sixteen patients discontinued narcotic use after treatment (62.5%). Twenty-three patients (89%) had a stable or improved American Spine Injury Association score at the last follow-up visit. No patient experienced radiation-induced myelopathy. Conclusions: The dose to paraspinal tumors has traditionally been limited to respect cord tolerance. With image-guided intensity-modulated radiotherapy, greater doses of radiation delivered in multiple fractions can be prescribed with excellent target coverage, effective palliation, and acceptable toxicity and local control.

  8. A fixed-jaw method to protect critical organs during intensity-modulated radiotherapy

    SciTech Connect

    Chen, Jiayun; Chen, Xinyuan; Huang, Manni; Dai, Jianrong

    2014-01-01

    Intensity-modulated radiotherapy (IMRT) plays an important role in cancer radiotherapy. For some patients being treated with IMRT, the extremely low tolerances of critical organs (such as lens, ovaries, and testicles) cannot be met during treatment planning. The aim of this article is to introduce a new planning method to overcome that problem. In current planning practice, jaw positions are automatically set to cover all target volumes by the planning system (e.g., Pinnacle{sup 3} system). Because of such settings, critical organs may be fully blocked by the multileaf collimator (MLC), but they still sit in the field that is shaped by collimator jaws. These critical organs receive doses from the transmission and leakage of MLC leaves. We manually fixed jaw positions to block them to further reduce such doses. This method has been used for different treatment sites in our clinic, and it was thoroughly evaluated in patients with radical hysterectomy plus ovarian transposition after surgery. For each patient, 2 treatment plans were designed with the same optimization parameters: the original plan with automatically chosen jaw positions (called O-plan) and the plan with fixed-jaw positions (named F-plan). In the F-plan, the jaws were manually fixed to block the ovaries. For target coverage, the mean conformity index (CI) of the F-plan (1.28 ± 0.02) was remarkably lower than that of the O-plan (1.53 ± 0.09) (p < 0.05). The F-plan and the O-plan performed similarly in target dose homogeneity. Meanwhile, for the critical organ sparing, the mean dose of both ovaries were much lower in the F-plan than that in the O-plan (p < 0.05). The V{sub 20}, V{sub 30}, and V{sub 40} of bladder were also lower in the F-plan (93.57 ± 1.98, 73.99 ± 5.76, and 42.33 ± 3.7, respectively) than those in the O-plan (97.98 ± 1.11, 85.07 ± 4.04, and 49.71 ± 3.63, respectively) (p < 0.05). The maximum dose to the spinal cord planning organ at risk (OAR) volume (PRV) in the O-plan (3940

  9. Extended field intensity-modulated radiotherapy plus concurrent nedaplatin treatment in cervical cancer

    PubMed Central

    LIU, YUNQIN; YU, JINMING; QIAN, LITING; ZHANG, HONGYAN; MA, JUN

    2016-01-01

    The present study assessed the efficacy and toxicity of definitive extended-field intensity-modulated radiotherapy (EF-IMRT) plus concurrent chemotherapy in cervical cancer. A total of 48 patients with cervical cancer received the planning target volume between 39.6 and 50.4 Gy in 1.8–2.0 Gy daily fractions, while the enlarged pelvic and/or para-aortic nodes were treated with a total dose of 55–60 Gy in 2.0–2.4 Gy daily fractions using simultaneous integrated boost-IMRT. All patients underwent high dose-rate brachytherapy. Concurrent to EF-IMRT, nedaplatin was administered weekly at a median dose of 30 mg/m2 (range, 25–40 mg/m2) for 5 weeks with a total of 150 mg/m2. Of the 48 patients, 46 patients exhibited initial complete responses and 2 patients had partial responses, with a response rate of 100%. After 4–24 months of treatment, 12 patients (27.08%) had local and/or distant failure and 39 patients (81.25%) were alive at the last follow-up. The 12-month overall survival (OS) and disease-free survival (DFS) were 87.5 and 75.8%, respectively, while the 24-month OS and DFS were 69.7 and 49.7%, respectively. Grade ≥3 acute neutropenia and thrombcytopenia occurred in 20 (41.7%) and 4 (8.3%) patients, respectively, while 2 patients (4.2%) developed grade ≥3 diarrhea and 2 (4.2%) had grade ≥3 late toxicities. However, no patients exhibited grade ≥3 vomiting. Thus, concurrent nedaplatin chemotherapy with definitive EF-IMRT was effective and relatively safe for treating patients with cervical cancer. Furthermore, EF-IMRT was able to deliver ≤60 Gy to enlarged para-aortic and/or pelvic nodes using simultaneous integrated boost without increased acute and late gastrointestinal toxicity. PMID:27123128

  10. Dosimetric investigation of breath-hold intensity-modulated radiotherapy for pancreatic cancer

    SciTech Connect

    Nakamura, Mitsuhiro; Kishimoto, Shun; Iwamura, Kohei; Shiinoki, Takehiro; Nakamura, Akira; Matsuo, Yukinori; Shibuya, Keiko; Hiraoka, Masahiro

    2012-01-15

    Purpose: To experimentally investigate the effects of variations in respiratory motion during breath-holding (BH) at end-exhalation (EE) on intensity-modulated radiotherapy (BH-IMRT) dose distribution using a motor-driven base, films, and an ionization chamber. Methods: Measurements were performed on a linear accelerator, which has a 120-leaf independently moving multileaf collimator with 5-mm leaf width at the isocenter for the 20-cm central field. Polystyrene phantoms with dimensions of 40 x 40 x 10 cm were set on a motor-driven base. All gantry angles of seven IMRT plans (a total of 35 fields) were changed to zero, and doses were then delivered to a film placed at a depth of 4 cm and an ionization chamber at a depth of 5 cm in the phantom with a dose rate of 600 MU/min under the following conditions: pulsation from the abdominal aorta and baseline drift with speeds of 0.2 mm/s (BD{sub 0.2mm/s}) and 0.4 mm/s (BD{sub 0.4mm/s}). As a reference for comparison, doses were also delivered to the chamber and film under stationary conditions. Results: In chamber measurements, means {+-} standard deviations of the dose deviations between stationary and moving conditions were -0.52% {+-} 1.03% (range: -3.41-1.05%), -0.07% {+-} 1.21% (range: -1.88-4.31%), and 0.03% {+-} 1.70% (range: -2.70-6.41%) for pulsation, BD{sub 0.2mm/s}, and BD{sub 0.4mm/s}, respectively. The {gamma} passing rate ranged from 99.5% to 100.0%, even with the criterion of 2%/1 mm for pulsation pattern. In the case of BD{sub 0.4mm/s}, the {gamma} passing rate for four of 35 fields (11.4%) did not reach 90% with a criterion of 3%/3 mm. The differences in {gamma} passing rate between BD{sub 0.2mm/s} and BD{sub 0.4mm/s} were statistically significant for each criterion. Taking {gamma} passing rates of > 90% as acceptable with a criterion of 3%/3 mm, large differences were observed in the {gamma} passing rate between the baseline drift of {<=}5 mm and that of >5 mm (minimum {gamma} passing rate: 92.0% vs 82

  11. Salivary Gland Tumors Treated With Adjuvant Intensity-Modulated Radiotherapy With or Without Concurrent Chemotherapy

    SciTech Connect

    Schoenfeld, Jonathan D.; Sher, David J.; Norris, Charles M.; Haddad, Robert I.; Posner, Marshall R.; Balboni, Tracy A.; Tishler, Roy B.

    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

  12. Nasopharyngeal Carcinoma in Children: Comparison of Conventional and Intensity-Modulated Radiotherapy

    SciTech Connect

    Laskar, Siddhartha Bahl, Gaurav; Muckaden, MaryAnn; Pai, Suresh K.; Gupta, Tejpal; Banavali, Shripad; Arora, Brijesh; Sharma, Dayanand; Kurkure, Purna A.; Ramadwar, Mukta; Viswanathan, Seethalaxhmi; Rangarajan, Venkatesh; Qureshi, Sajid; Deshpande, Deepak D.; Shrivastava, Shyam K.; Dinshaw, Ketayun A.

    2008-11-01

    Purpose: To evaluate the efficacy of intensity-modulated radiotherapy (IMRT) in reducing the acute toxicities associated with conventional RT (CRT) in children with nasopharyngeal carcinoma. Patients and Methods: A total of 36 children with nonmetastatic nasopharyngeal carcinoma, treated at the Tata Memorial Hospital between June 2003 and December 2006, were included in this study. Of the 36 patients, 28 were boys and 8 were girls, with a median age of 14 years; 4 (11%) had Stage II and 10 (28%) Stage III disease at presentation. All patients had undifferentiated carcinoma and were treated with a combination of chemotherapy and RT. Of the 36 patients, 19 underwent IMRT and 17 underwent CRT. Results: After a median follow-up of 27 months, the 2-year locoregional control, disease-free, and overall survival rate was 76.5%, 60.6%, and 71.3%, respectively. A significant reduction in acute Grade 3 toxicities of the skin (p = 0.006), mucous membrane (p = 0.033), and pharynx (p = 0.035) was noted with the use of IMRT. The median time to the development of Grade 2 toxicity was delayed with IMRT (skin, 35 vs. 25 days, p = 0.016; mucous-membrane, 39 vs. 27 days, p = 0.002; and larynx, 50 vs. 28 days, p = 0.009). The duration of RT significantly influenced disease-free survival on multivariate analysis (RT duration >52 days, hazard ratio = 5.49, 95% confidence interval, 1.14-26.45, p = 0.034). The average mean dose to the first and second planning target volume was 71.8 Gy and 62.5 Gy with IMRT compared with 66.3 Gy (p = 0.001) and 64.4 Gy (p = 0.046) with CRT, respectively. Conclusion: The results of our study have shown that IMRT significantly reduces and delays the onset of acute toxicity, resulting in improved tolerance and treatment compliance for children with nasopharyngeal carcinoma. Also, IMRT provided superior target coverage and normal tissue sparing compared with CRT.

  13. Experience-Based Quality Control of Clinical Intensity-Modulated Radiotherapy Planning

    SciTech Connect

    Moore, Kevin L.; Brame, R. Scott; Low, Daniel A.; Mutic, Sasa

    2011-10-01

    Purpose: To incorporate a quality control tool, according to previous planning experience and patient-specific anatomic information, into the intensity-modulated radiotherapy (IMRT) plan generation process and to determine whether the tool improved treatment plan quality. Methods and Materials: A retrospective study of 42 IMRT plans demonstrated a correlation between the fraction of organs at risk (OARs) overlapping the planning target volume and the mean dose. This yielded a model, predicted dose = prescription dose (0.2 + 0.8 [1 - exp(-3 overlapping planning target volume/volume of OAR)]), that predicted the achievable mean doses according to the planning target volume overlap/volume of OAR and the prescription dose. The model was incorporated into the planning process by way of a user-executable script that reported the predicted dose for any OAR. The script was introduced to clinicians engaged in IMRT planning and deployed thereafter. The script's effect was evaluated by tracking {delta} = (mean dose-predicted dose)/predicted dose, the fraction by which the mean dose exceeded the model. Results: All OARs under investigation (rectum and bladder in prostate cancer; parotid glands, esophagus, and larynx in head-and-neck cancer) exhibited both smaller {delta} and reduced variability after script implementation. These effects were substantial for the parotid glands, for which the previous {delta} = 0.28 {+-} 0.24 was reduced to {delta} = 0.13 {+-} 0.10. The clinical relevance was most evident in the subset of cases in which the parotid glands were potentially salvageable (predicted dose <30 Gy). Before script implementation, an average of 30.1 Gy was delivered to the salvageable cases, with an average predicted dose of 20.3 Gy. After implementation, an average of 18.7 Gy was delivered to salvageable cases, with an average predicted dose of 17.2 Gy. In the prostate cases, the rectum model excess was reduced from {delta} = 0.28 {+-} 0.20 to {delta} = 0.07 {+-} 0

  14. Distant Metastases in Head-and-Neck Squamous Cell Carcinoma Treated With Intensity-Modulated Radiotherapy

    SciTech Connect

    Yao Min; Lu Minggen; Savvides, Panayiotis S.; Rezaee, Rod; Zender, Chad A.; Lavertu, Pierre; Buatti, John M.; Machtay, Mitchell

    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

  15. Feasibility of dose escalation using intensity-modulated radiotherapy in posthysterectomy cervical carcinoma

    SciTech Connect

    D'Souza, Warren D. . E-mail: wdsou001@umaryland.edu; Ahamad, Anesa A.; Iyer, Revathy B.; Salehpour, Mohammad R.; Jhingran, Anuja; Eifel, Patricia J.

    2005-03-15

    Purpose: To evaluate retrospectively the utility of intensity-modulated radiotherapy (IMRT) in reducing the volume of normal tissues receiving radiation at varying dose levels when the female pelvis after hysterectomy is treated to doses of 50.4 Gy and 54 Gy. Methods and materials: Computed tomography scans from 10 patients who had previously undergone conventional postoperative RT were selected. The clinical tumor volume (vaginal apex and iliac nodes) and organs at risk were contoured. Margins were added to generate the planning tumor volume. The Pinnacle and Corvus planning systems were used to develop conventional and IMRT plans, respectively. Conventional four-field plans were prescribed to deliver 45 Gy (4F{sub 45Gy}) or 50.4 Gy; eight-field IMRT plans were prescribed to deliver 50.4 Gy (IMRT{sub 50.4Gy}) or 54 Gy (IMRT{sub 54Gy}) to the planning tumor volume. All plans were normalized so that {>=}97% of the planning tumor volume received the prescribed dose. Student's t test was used to compare the volumes of organs at risk receiving the same doses with different plans. Results: The mean volume of bowel receiving {>=}45 Gy was lower with the IMRT{sub 50.4Gy} (33% lower) and IMRT{sub 54Gy} (18% lower) plans than with the 4F{sub 45Gy} plan. The mean volume of rectum receiving {>=}45 Gy or {>=}50 Gy was also significantly reduced with the IMRT plans despite an escalation of the prescribed dose from 45 Gy with the conventional plans to 54 Gy with IMRT. The mean volume of bladder treated to 45 Gy was the same or slightly lower with the IMRT{sub 50.4Gy} and IMRT{sub 54Gy} plans compared with the 4F{sub 45Gy} plan. Compared with the 4F{sub 45Gy} plan, the IMRT{sub 50.4Gy} plan resulted in a smaller volume of bowel receiving 35-45 Gy and a larger volume of bowel receiving 50-55 Gy. Compared with the 4F{sub 45Gy} plan, the IMRT{sub 54Gy} plan resulted in smaller volumes of bowel receiving 45-50 Gy; however, small volumes of bowel received 55-60 Gy with the IMRT plan

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

    PubMed Central

    Sinn, M.; Ganeshan, R.; Graf, R.; Pelzer, U.; Stieler, J. M.; Striefler, J. K.; Bahra, M.; Wust, P.; Riess, H.

    2014-01-01

    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 (P = 0.293). This effect was translated into a significantly better median RT-specific overall survival of patients in the 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. PMID:25401140

  17. [Intensity-modulated radiotherapy of head and neck cancers. Dose constraint for spinal cord and brachial plexus].

    PubMed

    Boisselier, P; Racadot, S; Thariat, J; Graff, P; Pointreau, Y

    2016-10-01

    Given the ballistic opportunities it offers, intensity-modulated radiotherapy has emerged as the gold standard treatment for head and neck cancers. Protection of organs at risk is one of the objectives of optimization during the planning process. The compliance of dose constraints to the nervous system must be prioritized over all others. To avoid complications, it is recommended to respect a maximum dose of 50Gy to the spinal cord, and 60Gy to the brachial plexus using conventional fractionation of 2Gy per fraction. These constraints can be adapted depending on the clinical situation; they will probably be refocused by the follow-up of the IMRT studies. PMID:27614529

  18. [Intensity-modulated radiotherapy of head and neck cancers. Dose constraint for spinal cord and brachial plexus].

    PubMed

    Boisselier, P; Racadot, S; Thariat, J; Graff, P; Pointreau, Y

    2016-10-01

    Given the ballistic opportunities it offers, intensity-modulated radiotherapy has emerged as the gold standard treatment for head and neck cancers. Protection of organs at risk is one of the objectives of optimization during the planning process. The compliance of dose constraints to the nervous system must be prioritized over all others. To avoid complications, it is recommended to respect a maximum dose of 50Gy to the spinal cord, and 60Gy to the brachial plexus using conventional fractionation of 2Gy per fraction. These constraints can be adapted depending on the clinical situation; they will probably be refocused by the follow-up of the IMRT studies.

  19. Clinical applications of IMRT to adenocarcinoma of the prostate: Portal dose verification and intensity modulated neutron radiotherapy

    SciTech Connect

    Santanam, Lakshmi

    2005-01-01

    Intensity modulated radiotherapy (IMRT) provides an improvement in the conformality of radiotherapy dose distributions. Its application to photon radiotherapy for prostate adenocarcinoma is well established. A quality assurance tool for verifying photon IMRT treatment and the potential application of intensity modulation to neutron radiotherapy (IMNRT) to prostate cancer are investigated here. This study evaluates the use of an amorphous silicon flat panel imager for dose verification of photon IMRT fields. Various correction factors were developed to allow accurate estimation of the absorbed dose using this portal imager. The ratio of the dose measured with the portal imager to that measured using an ionization chamber was found to be 0.991{+-}0.026 for 23 measured IMRT fields. The study also yielded an accurate estimate of the relative beamlet intensity (fluence) at the plane of the detector. The raw difference between the relative beamlet intensity predicted by the EPID and that of the planning system for 23 IMRT fields was found to be -0.65{+-}2.69. These results demonstrate the capabilities of this imager as a robust IMRT quality assurance tool. An in-house optimization algorithm was used to optimize forward planned segments for the treatment of prostate cancer using IMNRT. The applicability of two different algorithms was investigated for IMNRT dose calculation, namely, the differential scatter air ratio (DSAR) and the finite size pencil beam (FSPB) algorithms. Measured profiles and absolute point doses were compared to results calculated by the treatment planning system. Dual ion-chamber measurements were performed to determine the individual neutron and gamma doses and to estimate the whole body dose equivalent. IMNRT plans retrospectively calculated for five prostate cancer patients provided dose distributions superior to conventional fast neutron therapy. When normalized to provide equivalent target coverage, the volume of the rectum and bladder receiving

  20. Modulated photon radiotherapy (XMRT): an algorithm for the simultaneous optimization of photon beamlet energy and intensity in external beam radiotherapy (EBRT) planning.

    PubMed

    McGeachy, Philip; Villarreal-Barajas, Jose Eduardo; Zinchenko, Yuriy; Khan, Rao

    2016-02-21

    This is a proof of principle study on an algorithm for optimizing external beam radiotherapy in terms of both photon beamlet energy and fluence. This simultaneous beamlet energy and fluence optimization is denoted modulated photon radiotherapy (XMRT). XMRT is compared with single-energy intensity modulated radiotherapy (IMRT) for five clinically relevant test geometries to determine whether treating beamlet energy as a decision variable improves the dose distributions. All test geometries were modelled in a cylindrical water phantom. XMRT optimized the fluence for 6 and 18 MV beamlets while IMRT optimized with only 6 MV and only 18 MV. CERR (computational environment for radiotherapy research) was used to calculate the dose deposition matrices and the resulting dose for XMRT and IMRT solutions. Solutions were compared via their dose volume histograms and dose metrics, such as the mean, maximum, and minimum doses for each structure. The homogeneity index (HI) and conformity number (CN) were calculated to assess the quality of the target dose coverage. Complexity of the resulting fluence maps was minimized using the sum of positive gradients technique. The results showed XMRT's ability to improve healthy-organ dose reduction while yielding comparable coverage of the target relative to IMRT for all geometries. All three energy-optimization approaches yielded similar HI and CNs for all geometries, as well as a similar degree of fluence map complexity. The dose reduction provided by XMRT was demonstrated by the relative decrease in the dose metrics for the majority of the organs at risk (OARs) in all geometries. Largest reductions ranged between 5% to 10% in the mean dose to OARs for two of the geometries when compared with both single-energy IMRT schemes. XMRT has shown potential dosimetric benefits through improved OAR sparing by allowing beam energy to act as a degree of freedom in the EBRT optimization process.

  1. Xerostomia and quality of life after intensity-modulated radiotherapy vs. conventional radiotherapy for early-stage nasopharyngeal carcinoma: Initial report on a randomized controlled clinical trial

    SciTech Connect

    Pow, Edmond; Kwong, Dora; McMillan, Anne S. . E-mail: annemcmillan@hku.hk; Wong, May; Sham, Jonathan; Leung, Lucullus; Leung, W. Keung

    2006-11-15

    Purpose: To compare directly the effect of intensity-modulated radiotherapy (IMRT) vs. conventional radiotherapy (CRT) on salivary flow and quality of life (QoL) in patients with early-stage nasopharyngeal carcinoma (NPC). Methods and Materials: Fifty-one patients with T2, N0/N1, M0 NPC took part in a randomized controlled clinical study and received IMRT or CRT. Stimulated whole (SWS) and parotid (SPS) saliva flow were measured and Medical Outcomes Short Form 36 (SF-36), European Organization for Research and Treatment of Cancer (EORTC) core quetionnaire, and EORTC head-and-neck module (QLQ-H and N35) were completed at baseline and 2, 6, and 12 months after radiotherapy. Results: Forty-six patients (88%) were in disease remission 12 months after radiotherapy. At 12 months postradiotherapy, 12 (50.0%) and 20 patients (83.3%) in the IMRT group had recovered at least 25% of preradiotherapy SWS and SPS flow respectively, compared with 1 (4.8%) and 2 patients (9.5%), respectively, in the CRT group. Global health scores showed continuous improvement in QoL after both treatments (p < 0.001). However, after 12 months subscale scores for role-physical, bodily pain, and physical function were significantly higher in the IMRT group, indicating a better condition (p < 0.05). Dry mouth and sticky saliva were problems in both groups 2 months after treatment. In the IMRT group, there was consistent improvement over time with xerostomia-related symptoms significantly less common than in the CRT group at 12 months postradiotherapy. Conclusions: IMRT was significantly better than CRT in terms of parotid sparing and improved QoL for early-stage disease. The findings support the case for assessment of health-related QoL in relation to head-and-neck cancer using a site-specific approach.

  2. Stereotactic Radiotherapy of Central Nervous System and Head and Neck Lesions, Using a Conformal Intensity-Modulated Radiotherapy System (Peacock™ System)

    PubMed Central

    Ammirati, Mario; Bernardo, Antonio; Ramsinghani, Nilam; Yakoob, Richard; Al-Ghazi, Matthew; Kuo, Jeffrey; Ammirati, Giuseppe

    2001-01-01

    The objective of this article is to evaluate single-fraction or fractionated stereotactic radiotherapy of central nervous system (CNS) and head and neck lesions using intensity-modulated radiotherapy (IMRT) with a commercially available system (Peacock™, Nomos Corporation, Sewickley, PA). This system allows tomotherapeutic delivery of intensity-modulated radiation, that is, the slice-by-slice treatment of the volume of interest with an intensity-modulated beam, making the delivery of highly conformal radiation to the target possible in both single or multiple fractions mode. During an 18-month period, 43 (21 males and 22 females) patients were treated, using a removable cranial screw-fixation device. Ages ranged from 10 to 77 years (mean, 52.2; median, 53.5). Intra- and extra-axial lesions, including head and neck malignancies and spine metastases, were treated. Clinical target volume ranged from 0.77 to 195 cm3 (mean, 47.8; median, 29.90). The dose distribution was normalized to the maximum and was prescribed, in most cases, at the 80% or 90% isodose line (range, 65 to 96%; median, 85%; mean, 83.4%) and ranged from 14 to 80 Gy (mean, 48; median, 50). The number of fractions ranged from 1 to 40 (mean, 23; median, 25). In all but one patient, 90% of the prescription isodose line covered 100% of the clinical target volume. The heterogeneity index (the ratio between the maximum radiation dose and the prescribed dose) ranged between 1.0 and 1.50, whereas the conformity index (the ratio between the volume encompassed by the prescription isodose line and the clinical target volume) ranged between 1.0 and 4.5. There were no complications related to the radiation treatment. With a median follow-up of 6 months, more than 70% of our patients showed decreased lesion size. Stereotactic IMRT of CNS and head and neck lesions can be delivered safely and accurately. The Peacock system delivers stereotactic radiation in single or multiple fractions and has no volume limitations

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

    SciTech Connect

    Kole, Thomas P.; Aghayere, Osarhieme; Kwah, Jason; Yorke, Ellen D.; Goodman, Karyn A.

    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

  4. Radiotherapy for Early Mediastinal Hodgkin Lymphoma According to the German Hodgkin Study Group (GHSG): The Roles of Intensity-Modulated Radiotherapy and Involved-Node Radiotherapy

    SciTech Connect

    Koeck, Julia; Abo-Madyan, Yasser; Lohr, Frank; Stieler, Florian; Kriz, Jan; Mueller, Rolf-Peter; Wenz, Frederik; Eich, Hans Theodor

    2012-05-01

    Purpose: Cure rates of early Hodgkin lymphoma (HL) are high, and avoidance of late complications and second malignancies have become increasingly important. This comparative treatment planning study analyzes to what extent target volume reduction to involved-node (IN) and intensity-modulated (IM) radiotherapy (RT), compared with involved-field (IF) and three-dimensional (3D) RT, can reduce doses to organs at risk (OAR). Methods and Materials: Based on 20 computed tomography (CT) datasets of patients with early unfavorable mediastinal HL, we created treatment plans for 3D-RT and IMRT for both the IF and IN according to the guidelines of the German Hodgkin Study Group (GHSG). As OAR, we defined heart, lung, breasts, and spinal cord. Dose-volume histograms (DVHs) were evaluated for planning target volumes (PTVs) and OAR. Results: Average IF-PTV and IN-PTV were 1705 cm{sup 3} and 1015 cm{sup 3}, respectively. Mean doses to the PTVs were almost identical for all plans. For IF-PTV/IN-PTV, conformity was better with IMRT and homogeneity was better with 3D-RT. Mean doses to the heart (17.94/9.19 Gy for 3D-RT and 13.76/7.42 Gy for IMRT) and spinal cord (23.93/13.78 Gy for 3D-RT and 19.16/11.55 Gy for IMRT) were reduced by IMRT, whereas mean doses to lung (10.62/8.57 Gy for 3D-RT and 12.77/9.64 Gy for IMRT) and breasts (left 4.37/3.42 Gy for 3D-RT and 6.04/4.59 Gy for IMRT, and right 2.30/1.63 Gy for 3D-RT and 5.37/3.53 Gy for IMRT) were increased. Volume exposed to high doses was smaller for IMRT, whereas volume exposed to low doses was smaller for 3D-RT. Pronounced benefits of IMRT were observed for patients with lymph nodes anterior to the heart. IN-RT achieved substantially better values than IF-RT for almost all OAR parameters, i.e., dose reduction of 20% to 50%, regardless of radiation technique. Conclusions: Reduction of target volume to IN most effectively improves OAR sparing, but is still considered investigational. For the time being, IMRT should be considered for

  5. Clinical Outcome in Posthysterectomy Cervical Cancer Patients Treated With Concurrent Cisplatin and Intensity-Modulated Pelvic Radiotherapy: Comparison With Conventional Radiotherapy

    SciTech Connect

    Chen, M.-F.; Tseng, C.-J.; Tseng, C.-C.; Kuo, Y.-C.; Yu, C.-Y.; Chen, W.-C. . E-mail: rto_chen@yahoo.com.tw

    2007-04-01

    Purpose: To assess local control and acute and chronic toxicity with intensity-modulated radiation therapy (IMRT) as adjuvant treatment of cervical cancer. Methods and Materials: Between April 2002 and February 2006, 68 patients at high risk of cervical cancer after hysterectomy were treated with adjuvant pelvic radiotherapy and concurrent chemotherapy. Adjuvant chemotherapy consisted of cisplatin (50 mg/m{sup 2}) for six cycles every week. Thirty-three patients received adjuvant radiotherapy by IMRT. Before the IMRT series was initiated, 35 other patients underwent conventional four-field radiotherapy (Box-RT). The two groups did not differ significantly in respect of clinicopathologic and treatment factors. Results: IMRT provided compatible local tumor control compared with Box-RT. The actuarial 1-year locoregional control for patients in the IMRT and Box-RT groups was 93% and 94%, respectively. IMRT was well tolerated, with significant reduction in acute gastrointestinal (GI) and genitourinary (GU) toxicities compared with the Box-RT group (GI 36 vs. 80%, p = 0.00012; GU 30 vs. 60%, p = 0.022). Furthermore, the IMRT group had lower rates of chronic GI and GU toxicities than the Box-RT patients (GI 6 vs. 34%, p = 0.002; GU 9 vs. 23%, p = 0.231). Conclusion: Our results suggest that IMRT significantly improved the tolerance to adjuvant chemoradiotherapy with compatible locoregional control compared with conventional Box-RT. However, longer follow-up and more patients are needed to confirm the benefits of IMRT.

  6. Spine radiosurgery for the local treatment of spine metastases: Intensity-modulated radiotherapy, image guidance, clinical aspects and future directions

    PubMed Central

    de Moraes, Fabio Ynoe; Taunk, Neil Kanth; Laufer, Ilya; Neves-Junior, Wellington Furtado Pimenta; Hanna, Samir Abdallah; de Andrade Carvalho, Heloisa; Yamada, Yoshiya

    2016-01-01

    Many cancer patients will develop spinal metastases. Local control is important for preventing neurologic compromise and to relieve pain. Stereotactic body radiotherapy or spinal radiosurgery is a new radiation therapy technique for spinal metastasis that can deliver a high dose of radiation to a tumor while minimizing the radiation delivered to healthy, neighboring tissues. This treatment is based on intensity-modulated radiotherapy, image guidance and rigid immobilization. Spinal radiosurgery is an increasingly utilized treatment method that improves local control and pain relief after delivering ablative doses of radiation. Here, we present a review highlighting the use of spinal radiosurgery for the treatment of metastatic tumors of the spine. The data used in the review were collected from both published studies and ongoing trials. We found that spinal radiosurgery is safe and provides excellent tumor control (up to 94% local control) and pain relief (up to 96%), independent of histology. Extensive data regarding clinical outcomes are available; however, this information has primarily been generated from retrospective and nonrandomized prospective series. Currently, two randomized trials are enrolling patients to study clinical applications of fractionation schedules spinal Radiosurgery. Additionally, a phase I clinical trial is being conducted to assess the safety of concurrent stereotactic body radiotherapy and ipilimumab for spinal metastases. Clinical trials to refine clinical indications and dose fractionation are ongoing. The concomitant use of targeted agents may produce better outcomes in the future. PMID:26934240

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

    NASA Astrophysics Data System (ADS)

    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.

  8. A comparison between cobalt and linear accelerator-based treatment plans for conformal and intensity-modulated radiotherapy.

    PubMed

    Adams, E J; Warrington, A P

    2008-04-01

    The simplicity of cobalt units gives them the advantage of reduced maintenance, running costs and downtime when compared with linear accelerators. However, treatments carried out on such units are typically limited to simple techniques. This study has explored the use of cobalt beams for conformal and intensity-modulated radiotherapy (IMRT). Six patients, covering a range of treatment sites, were planned using both X-ray photons (6/10 MV) and cobalt-60 gamma rays (1.17 and 1.33 MeV). A range of conformal and IMRT techniques were considered, as appropriate. Conformal plans created using cobalt beams for small breast, meningioma and parotid cases were found to compare well with those created using X-ray photons. By using additional fields, acceptable conformal plans were also created for oesophagus and prostate cases. IMRT plans were found to be of comparable quality for meningioma, parotid and thyroid cases on the basis of dose-volume histogram analysis. We conclude that it is possible to plan high-quality radical radiotherapy treatments for cobalt units. A well-designed beam blocking/compensation system would be required to enable a practical and efficient alternative to multileaf collimator (MLC)-based linac treatments to be offered. If cobalt units were to have such features incorporated into them, they could offer considerable benefits to the radiotherapy community.

  9. Quality of Life After Hypofractionated Concomitant Intensity-Modulated Radiotherapy Boost for High-Risk Prostate Cancer

    SciTech Connect

    Quon, Harvey; Cheung, Patrick C.F.; Loblaw, D. Andrew; Morton, Gerard; Pang, Geordi; Szumacher, Ewa; Danjoux, Cyril; Choo, Richard; Kiss, Alex; Mamedov, Alexandre; Deabreu, Andrea

    2012-06-01

    Purpose: To evaluate the change in health-related quality of life (QOL) of patients with high-risk prostate cancer treated using hypofractionated radiotherapy combined with long-term androgen deprivation therapy. Methods and Materials: A prospective Phase I-II study enrolled patients with any of the following: clinical Stage T3 disease, prostate-specific antigen level {>=}20 ng/mL, or Gleason score 8-10. Radiotherapy consisted of 45 Gy (1.8 Gy per fraction) to the pelvic lymph nodes with a concomitant 22.5 Gy intensity-modulated radiotherapy boost to the prostate, for a total of 67.5 Gy (2.7 Gy per fraction) in 25 fractions over 5 weeks. Daily image guidance was performed using three gold seed fiducials. Quality of life was measured using the Expanded Prostate Cancer Index Composite (EPIC), a validated tool that assesses four primary domains (urinary, bowel, sexual, and hormonal). Results: From 2004 to 2007, 97 patients were treated. Median follow-up was 39 months. Compared with baseline, at 24 months there was no statistically significant change in the mean urinary domain score (p = 0.99), whereas there were decreases in the bowel (p < 0.01), sexual (p < 0.01), and hormonal (p < 0.01) domains. The proportion of patients reporting a clinically significant difference in EPIC urinary, bowel, sexual, and hormonal scores at 24 months was 27%, 31%, 55%, and 60%, respectively. However, moderate and severe distress related to these symptoms was minimal, with increases of only 3% and 5% in the urinary and bowel domains, respectively. Conclusions: Hypofractionated radiotherapy combined with long-term androgen deprivation therapy was well tolerated. Although there were modest rates of clinically significant patient-reported urinary and bowel toxicity, most of this caused only mild distress, and moderate and severe effects on QOL were limited. Additional follow-up is ongoing to characterize long-term QOL.

  10. Combinational use of conformal and intensity-modulated beams in radiotherapy planning

    NASA Astrophysics Data System (ADS)

    Coolens, Catherine; Webb, Steve; Evans, Phil M.; Seco, Joao

    2003-06-01

    Intensity-modulated (IM) beam profiles computed by inverse-planning systems tend to be complex and may have multiple spatial minima and maxima. In addition to the structure originating from the treatment objectives, beam profiles might contain stochastic structure or noise and numerical artefacts, which present certain practical difficulties. The combinational use of conformal and intensity-modulated beams could be a different method of making the total fluence distribution less noisy and deliverable without compromising the advantages of IMRT. The investigation of this possibility provided the basis for this paper. A treatment-planning study was performed to compare plans combining modulated and unmodulated beams with a 5-field, equally spaced, full IMRT plan for treating the prostate and seminal vesicles in three patients. Beam angles for this study were 0°, 72°, 144°, 216° and 288°. Additionally, a study was performed on a patient with a different beam arrangement (36°, 108°, 180°, 252°, 324°) from the first study to test the obtained results. This study has demonstrated that it is possible to substitute up to two conformal beams in the originally full IMRT plan when carefully selecting the conformal beam angles. Making the anterior beam (0°) and an anterior oblique beam (between 0° and 90°) conformal leads to a reduction in the total number of monitor units and segments of about 15% and 39%, respectively. Additionally, these two open fields can be used for simpler treatment verification.

  11. Limited Advantages of Intensity-Modulated Radiotherapy Over 3D Conformal Radiation Therapy in the Adjuvant Management of Gastric Cancer

    SciTech Connect

    Alani, Shlomo; Soyfer, Viacheslav; Strauss, Natan; Schifter, Dan; Corn, Benjamin W.

    2009-06-01

    Purpose: Although chemoradiotherapy was considered the standard adjuvant treatment for gastric cancer, a recent Phase III trial (Medical Research Council Adjuvant Gastric Infusional Chemotherapy [MAGIC]) did not include radiotherapy in the randomization scheme because it was considered expendable. Given radiotherapy's potential, efforts needed to be made to optimize its use for treating gastric cancer. We assessed whether intensity-modulated radiotherapy (IMRT) could improve upon our published results in patients treated with three-dimensional (3D) conformal therapy. Methods and Materials: Fourteen patients with adenocarcinoma of the stomach were treated with adjuvant chemoradiotherapy using a noncoplanar four-field arrangement. Subsequently, a nine-field IMRT plan was designed using a CMS Xio IMRT version 4.3.3 module. Two IMRT beam arrangements were evaluated: beam arrangement 1 consisted of gantry angles of 0 deg., 53 deg., 107 deg., 158 deg., 204 deg., 255 deg., and 306 deg.. Beam arrangement 2 consisted of gantry angles of 30 deg., 90 deg., 315 deg., and 345 deg.; a gantry angle of 320 deg./couch, 30 deg.; and a gantry angle of 35{sup o}/couch, 312{sup o}. Both the target volume coverage and the dose deposition in adjacent critical organs were assessed in the plans. Dose-volume histograms were generated for the clinical target volume, kidneys, spine, and liver. Results: Comparison of the clinical target volumes revealed satisfactory coverage by the 95% isodose envelope using either IMRT or 3D conformal therapy. However, IMRT was only marginally better than 3D conformal therapy at protecting the spine and kidneys from radiation. Conclusions: IMRT confers only a marginal benefit in the adjuvant treatment of gastric cancer and should be used only in the small subset of patients with risk factors for kidney disease or those with a preexisting nephropathy.

  12. Positron Emission Tomography-Guided, Focal-Dose Escalation Using Intensity-Modulated Radiotherapy for Head and Neck Cancer

    SciTech Connect

    Madani, Indira . E-mail: indira@krtkg1.ugent.be; Duthoy, Wim; Derie, Cristina R.N.; De Gersem, Werner Ir.; Boterberg, Tom; Saerens, Micky; Jacobs, Filip Ir.; Gregoire, Vincent; Lonneux, Max; Vakaet, Luc; Vanderstraeten, Barbara; Bauters, Wouter; Bonte, Katrien; Thierens, Hubert; Neve, Wilfried de

    2007-05-01

    Purpose: To assess the feasibility of intensity-modulated radiotherapy (IMRT) using positron emission tomography (PET)-guided dose escalation, and to determine the maximum tolerated dose in head and neck cancer. Methods and Materials: A Phase I clinical trial was designed to escalate the dose limited to the [{sup 18}-F]fluoro-2-deoxy-D-glucose positron emission tomography ({sup 18}F-FDG-PET)-delineated subvolume within the gross tumor volume. Positron emission tomography scanning was performed in the treatment position. Intensity-modulated radiotherapy with an upfront simultaneously integrated boost was employed. Two dose levels were planned: 25 Gy (level I) and 30 Gy (level II), delivered in 10 fractions. Standard IMRT was applied for the remaining 22 fractions of 2.16 Gy. Results: Between 2003 and 2005, 41 patients were enrolled, with 23 at dose level I, and 18 at dose level II; 39 patients completed the planned therapy. The median follow-up for surviving patients was 14 months. Two cases of dose-limiting toxicity occurred at dose level I (Grade 4 dermitis and Grade 4 dysphagia). One treatment-related death at dose level II halted the study. Complete response was observed in 18 of 21 (86%) and 13 of 16 (81%) evaluated patients at dose levels I and II (p < 0.7), respectively, with actuarial 1-year local control at 85% and 87% (p n.s.), and 1-year overall survival at 82% and 54% (p = 0.06), at dose levels I and II, respectively. In 4 of 9 patients, the site of relapse was in the boosted {sup 18}F-FDG-PET-delineated region. Conclusions: For head and neck cancer, PET-guided dose escalation appears to be well-tolerated. The maximum tolerated dose was not reached at the investigated dose levels.

  13. A Phase II Trial of Arc-Based Hypofractionated Intensity-Modulated Radiotherapy in Localized Prostate Cancer

    SciTech Connect

    Lock, Michael; Best, Lara; Wong, Eugene; Bauman, Glenn; D'Souza, David; Venkatesan, Varagur; Sexton, Tracy; Ahmad, Belal; Izawa, Jonathan; Rodrigues, George

    2011-08-01

    Purpose: To evaluate acute and late genitourinary (GU) and gastrointestinal (GI) toxicity and biochemical control of hypofractionated, image-guided (fiducial markers or ultrasound guidance), simplified intensity-modulated arc therapy for localized prostate cancer. Methods and Materials: This Phase II prospective clinical trial for T1a-2cNXM0 prostate cancer enrolled 66 patients who received 63.2 Gy in 20 fractions over 4 weeks. Fiducial markers were used for image guidance in 30 patients and daily ultrasound for the remainder. Toxicity was scored according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0. Results: Median follow-up was 36 months. Acute Phase Grade 2 and 3 toxicity was 34% and 9% for GU vs. 25% and 10% for GI symptoms. One Grade 4 acute GI toxicity occurred in a patient with unrecognized Crohn's disease. Late Grade 2 and 3 toxicity for GU was 14% and 5%, and GI toxicity was 25% and 3%. One late GI Grade 4 toxicity was observed in a patient with significant comorbidities (anticoagulation, vascular disease). Acute GI toxicity {>=}Grade 2 was shown to be a predictor for late toxicity Grade {>=}2 (p < 0.001). The biochemical disease-free survival at 3 years was 95%. Conclusions: Hypofractionated simplified intensity-modulated arc therapy radiotherapy given as 63.2 Gy in 20 fractions demonstrated promising biochemical control rates; however, higher rates of acute Grade 3 GU and GI toxicity and higher late Grade 2 GU and GI toxicity were noted. Ongoing randomized controlled trials should ultimately clarify issues regarding patient selection and the true rate of severe toxicity that can be directly attributed to hypofractionated radiotherapy.

  14. A Matched Control Analysis of Adjuvant and Salvage High-Dose Postoperative Intensity-Modulated Radiotherapy for Prostate Cancer

    SciTech Connect

    Ost, Piet; De Troyer, Bart; Fonteyne, Valerie; Oosterlinck, Willem; De Meerleer, Gert

    2011-08-01

    Purpose: It is unclear whether immediate adjuvant radiotherapy for high-risk disease at prostatectomy (capsule perforation, seminal vesicle invasion, and/or positive surgical margins) is equivalent to delayed salvage radiotherapy at biochemical recurrence. We performed a matched case analysis comparing high-dose adjuvant intensity modulated radiotherapy (A-IMRT) with salvage IMRT (S-IMRT). Methods and Materials: One hundred forty-four patients with high-risk disease at prostatectomy were referred for A-IMRT, and 134 patients with high-risk disease were referred at biochemical recurrence (rising prostate-specific antigen [PSA], following prostatectomy, above 0.2 ng/ml) for S-IMRT. Patients were matched in a 1:1 ratio according to preoperative PSA level, Gleason score, and pT stage. Median doses of 74 Gy and 76 Gy were prescribed for A-IMRT and S-IMRT, respectively. We report biochemical relapse free survival (bRFS) rates using the Kaplan-Meier method. Univariate and multivariate analyses were used to examine tumour- and treatment-related factors. Results: A total of 178 patients were matched (89:89). From the end of radiotherapy, the median follow-up was 36 months for both groups. The 3-year bRFS rate for the A-IMRT group was 90% compared to 65% for the S-IMRT group (p < 0.05). On multivariate analysis, S-IMRT, Gleason grades of {>=}4+3, perineural invasion, preoperative PSA level of {>=}10 ng/ml, and omission of androgen deprivation (AD) were independent predictors for a reduced bRFS (p < 0.05). From the date of surgery, the median follow-up was 43 and 60 months for A-IMRT and S-IMRT, respectively. The 3-year bRFS rate for A-IMRT was 91% compared to 79% for S-IMRT (p < 0.05). On multivariate analysis, Gleason grades of {>=}4+3, perineural invasion, and omission of AD were independent predictors for a reduced bRFS (p < 0.05). S-IMRT was no longer an independent prognostic factor (p = 0.08). Conclusions: High-dose A-IMRT significantly improves 3-year bRFS compared to

  15. Superiority of helical tomotherapy on liver sparing and dose escalation in hepatocellular carcinoma: a comparison study of three-dimensional conformal radiotherapy and intensity-modulated radiotherapy

    PubMed Central

    Zhao, Qianqian; Wang, Renben; Zhu, Jian; Jin, Linzhi; Zhu, Kunli; Xu, Xiaoqing; Feng, Rui; Jiang, Shumei; Qi, Zhonghua; Yin, Yong

    2016-01-01

    Background and purpose To compare the difference of liver sparing and dose escalation between three-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiotherapy (IMRT), and helical tomotherapy (HT) for hepatocellular carcinoma. Patients and methods Sixteen unresectable HCC patients were enrolled in this study. First, some evaluation factors of 3DCRT, IMRT, and HT plans were calculated with prescription dose at 50 Gy/25 fractions. Then, the doses were increased using HT or IMRT independently until either the plans reached 70 Gy or any normal tissue reached the dose limit according to quantitative analysis of normal tissue effects in the clinic criteria. Results The conformal index of 3DCRT was lower than that of IMRT (P<0.001) or HT (P<0.001), and the homogeneity index of 3DCRT was higher than that of IMRT (P<0.001) or HT (P<0.001). HT took the longest treatment time (P<0.001). For V50% (fraction of normal liver treated to at least 50% of the isocenter dose) of the normal liver, there was a significant difference: 3DCRT > IMRT > HT (P<0.001). HT had a lower Dmean (mean dose) and V20 (Vn, the percentage of organ volume receiving ≥n Gy) of liver compared with 3DCRT (P=0.005 and P=0.005, respectively) or IMRT (P=0.508 and P=0.007, respectively). Dmean of nontarget normal liver and V30 of liver were higher for 3DCRT than IMRT (P=0.005 and P=0.005, respectively) or HT (P=0.005 and P=0.005, respectively). Seven patients in IMRT (43.75%) and nine patients in HT (56.25%) reached the isodose 70 Gy, meeting the dose limit of the organs at risk. Conclusion HT may provide significantly better liver sparing and allow more patients to achieve higher prescription dose in HCC radiotherapy. PMID:27445485

  16. Hippocampal-Sparing Whole-Brain Radiotherapy: A 'How-To' Technique Using Helical Tomotherapy and Linear Accelerator-Based Intensity-Modulated Radiotherapy

    SciTech Connect

    Gondi, Vinai; Tolakanahalli, Ranjini; Mehta, Minesh P.; Tewatia, Dinesh; Rowley, Howard; Kuo, John S.; Khuntia, Deepak; Tome, Wolfgang A.

    2010-11-15

    Purpose: Sparing the hippocampus during cranial irradiation poses important technical challenges with respect to contouring and treatment planning. Herein we report our preliminary experience with whole-brain radiotherapy using hippocampal sparing for patients with brain metastases. Methods and Materials: Five anonymous patients previously treated with whole-brain radiotherapy with hippocampal sparing were reviewed. The hippocampus was contoured, and hippocampal avoidance regions were created using a 5-mm volumetric expansion around the hippocampus. Helical tomotherapy and linear accelerator (LINAC)-based intensity-modulated radiotherapy (IMRT) treatment plans were generated for a prescription dose of 30 Gy in 10 fractions. Results: On average, the hippocampal avoidance volume was 3.3 cm{sup 3}, occupying 2.1% of the whole-brain planned target volume. Helical tomotherapy spared the hippocampus, with a median dose of 5.5 Gy and maximum dose of 12.8 Gy. LINAC-based IMRT spared the hippocampus, with a median dose of 7.8 Gy and maximum dose of 15.3 Gy. On a per-fraction basis, mean dose to the hippocampus (normalized to 2-Gy fractions) was reduced by 87% to 0.49 Gy{sub 2} using helical tomotherapy and by 81% to 0.73 Gy{sub 2} using LINAC-based IMRT. Target coverage and homogeneity was acceptable with both IMRT modalities, with differences largely attributed to more rapid dose fall-off with helical tomotherapy. Conclusion: Modern IMRT techniques allow for sparing of the hippocampus with acceptable target coverage and homogeneity. Based on compelling preclinical evidence, a Phase II cooperative group trial has been developed to test the postulated neurocognitive benefit.

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

    PubMed Central

    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

  18. Recurrence in Region of Spared Parotid Gland After Definitive Intensity-Modulated Radiotherapy for Head and Neck Cancer

    SciTech Connect

    Cannon, Donald M.; Lee, Nancy Y.

    2008-03-01

    Purpose: To discuss the implications of three examples of periparotid recurrence after definitive intensity-modulated radiotherapy (IMRT) for head and neck cancer (HNC). Methods and Materials: We present 3 patients with HNC who underwent definitive IMRT with concurrent chemotherapy and later had treatment failure in or near a spared parotid gland. Two patients had bilateral multilevel nodal disease, and all had Level II nodal disease ipsilateral to the site of recurrence. The patients were treated using dose-painting IMRT with a dose of 70 Gy to the gross tumor volume and 59.4 Gy or 54 Gy to the high-risk or low-risk clinical tumor volume, respectively. The parotid glands were spared bilaterally. The patients had not undergone any surgical treatment for HNC before radiotherapy. Results: All patients had treatment failure in the region of a spared parotid gland. Failure in the 2 patients with bilateral multilevel nodal involvement occurred in the periparotid lymph nodes. The third patient developed a dermal metastasis near the tail of a spared parotid gland. On pretreatment imaging, the 2 patients with nodal failure had small nonspecific periparotid nodules that showed no hypermetabolic activity on positron emission tomography. Conclusion: For HNC patients receiving definitive IMRT, nonspecific positron emission tomography-negative periparotid nodules on pretreatment imaging should raise the index of suspicion for subclinical disease in the presence of multilevel or Level II nodal metastases. Additional evaluation of such nodules might be indicated before sparing the ipsilateral parotid gland.

  19. [Intensity-modulated radiotherapy for head and neck cancer. Dose constraint for salivary gland and mandible].

    PubMed

    Pointreau, Y; Lizée, T; Bensadoun, R-J; Boisselier, P; Racadot, S; Thariat, J; Graff, P

    2016-10-01

    Intensity-modulated radiation therapy (IMRT) is the gold standard for head and neck irradiation. It allows better protection to the organs at risk such as salivary glands and mandible, and can reduce the frequency of xerostomia, trismus and osteoradionecrosis. At the time of treatment planning, the mean dose to a single parotid gland should be kept below 26Gy, the mean dose to a single submandibular gland below 39Gy, the mean dose to the mandible below 60 to 65Gy and the D2% to a single temporomandibular joint below 65Gy. These dose constraints could be further improved with data extracted from cohorts of patients receiving IMRT exclusively. The dose administered to the target volumes should not be lessened to spare the salivary glands or mandible.

  20. Carotid-Sparing Intensity-Modulated Radiotherapy for Early-Stage Squamous Cell Carcinoma of the True Vocal Cord

    SciTech Connect

    Chera, Bhishamjit S.; Amdur, Robert J.; Morris, Christopher G.; Mendenhall, William M.

    2010-08-01

    Purpose: To compare radiation doses to carotid arteries among various radiotherapy techniques for treatment of early-stage squamous cell carcinoma (SCC) of the true vocal cords. Methods and Materials: Five patients were simulated using computed tomography (CT). Clinical and planning target volumes (PTV) were created for bilateral and unilateral stage T1 vocal cord cancers. Planning risk volumes for the carotid arteries and spinal cord were delineated. For each patient, three treatment plans were designed for bilateral and unilateral target volumes: opposed laterals (LATS), three-dimensional conformal radiotherapy (3DCRT), and intensity-modulated radiotherapy (IMRT), for a total of 30 plans. More than 95% of the PTV received the prescription dose (63Gy at 2.25 Gy per treatment). Results: Carotid dose was lowest with IMRT. With a bilateral vocal cord target, the median carotid dose was 10Gy with IMRT vs. 25 Gy with 3DCRT and 38 Gy with LATS (p < 0.05); with a unilateral target, the median carotid dose was 4 Gy with IMRT vs. 19 Gy with 3DCRT and 39 Gy with LATS (p < 0.05). The dosimetric tradeoff with IMRT is a small area of high dose in the PTV. The worst heterogeneity results were at a maximum point dose of 80 Gy (127%) in a unilateral target that was close to the carotid. Conclusions: There is no question that IMRT can reduce the dose to the carotid arteries in patients with early-stage vocal cord cancer. The question is whether the potential advantage of reducing the carotid dose outweighs the risk of tumor recurrence due to contouring errors and organ motion and the risk of complications from dose heterogeneity.

  1. Decreasing Temporal Lobe Dose With Five-Field Intensity-Modulated Radiotherapy for Treatment of Pituitary Macroadenomas

    SciTech Connect

    Parhar, Preeti K.; Duckworth, Tamara; Shah, Parinda; DeWyngaert, J. Keith; Narayana, Ashwatha; Formenti, Silvia C.; Shah, Jinesh N.

    2010-10-01

    Purpose: To compare temporal lobe dose delivered by three pituitary macroadenoma irradiation techniques: three-field three-dimensional conformal radiotherapy (3D-CRT), three-field intensity-modulated radiotherapy (3F IMRT), and a proposed novel alternative of five-field IMRT (5F IMRT). Methods and Materials: Computed tomography-based external beam radiotherapy planning was performed for 15 pituitary macroadenoma patients treated at New York University between 2002 and 2007 using: 3D-CRT (two lateral, one midline superior anterior oblique [SAO] beams), 3F IMRT (same beam angles), and 5F IMRT (same beam angles with additional right SAO and left SAO beams). Prescription dose was 45 Gy. Target volumes were: gross tumor volume (GTV) = macroadenoma, clinical target volume (CTV) = GTV, and planning target volume = CTV + 0.5 cm. Structure contouring was performed by two radiation oncologists guided by an expert neuroradiologist. Results: Five-field IMRT yielded significantly decreased temporal lobe dose delivery compared with 3D-CRT and 3F IMRT. Temporal lobe sparing with 5F IMRT was most pronounced at intermediate doses: mean V25Gy (% of total temporal lobe volume receiving {>=}25 Gy) of 13% vs. 28% vs. 29% for right temporal lobe and 14% vs. 29% vs. 30% for left temporal lobe for 5F IMRT, 3D-CRT, and 3F IMRT, respectively (p < 10{sup -7} for 5F IMRT vs. 3D-CRT and 5F IMRT vs. 3F IMRT). Five-field IMRT plans did not compromise target coverage, exceed normal tissue dose constraints, or increase estimated brain integral dose. Conclusions: Five-field IMRT irradiation technique results in a statistically significant decrease in the dose to the temporal lobes and may thus help prevent neurocognitive sequelae in irradiated pituitary macroadenoma patients.

  2. Intensity-Modulated Radiotherapy for Locally Advanced Non-Small-Cell Lung Cancer: A Dose-Escalation Planning Study

    SciTech Connect

    Lievens, Yolande; Nulens, An; Gaber, Mousa Amr; Defraene, Gilles; De Wever, Walter; Stroobants, Sigrid; Van den Heuvel, Frank

    2011-05-01

    Purpose: To evaluate the potential for dose escalation with intensity-modulated radiotherapy (IMRT) in positron emission tomography-based radiotherapy planning for locally advanced non-small-cell lung cancer (LA-NSCLC). Methods and Materials: For 35 LA-NSCLC patients, three-dimensional conformal radiotherapy and IMRT plans were made to a prescription dose (PD) of 66 Gy in 2-Gy fractions. Dose escalation was performed toward the maximal PD using secondary endpoint constraints for the lung, spinal cord, and heart, with de-escalation according to defined esophageal tolerance. Dose calculation was performed using the Eclipse pencil beam algorithm, and all plans were recalculated using a collapsed cone algorithm. The normal tissue complication probabilities were calculated for the lung (Grade 2 pneumonitis) and esophagus (acute toxicity, grade 2 or greater, and late toxicity). Results: IMRT resulted in statistically significant decreases in the mean lung (p <.0001) and maximal spinal cord (p = .002 and 0005) doses, allowing an average increase in the PD of 8.6-14.2 Gy (p {<=}.0001). This advantage was lost after de-escalation within the defined esophageal dose limits. The lung normal tissue complication probabilities were significantly lower for IMRT (p <.0001), even after dose escalation. For esophageal toxicity, IMRT significantly decreased the acute NTCP values at the low dose levels (p = .0009 and p <.0001). After maximal dose escalation, late esophageal tolerance became critical (p <.0001), especially when using IMRT, owing to the parallel increases in the esophageal dose and PD. Conclusion: In LA-NSCLC, IMRT offers the potential to significantly escalate the PD, dependent on the lung and spinal cord tolerance. However, parallel increases in the esophageal dose abolished the advantage, even when using collapsed cone algorithms. This is important to consider in the context of concomitant chemoradiotherapy schedules using IMRT.

  3. Dosimetric research on intensity-modulated arc radiotherapy planning for left breast cancer after breast-preservation surgery

    SciTech Connect

    Yin Yong; Chen Jinhu; Sun Tao; Ma Changsheng; Lu Jie; Liu Tonghai; Wang Ruozheng

    2012-10-01

    Intensity-modulated radiotherapy (IMRT) has played an important role in breast cancer radiotherapy after breast-preservation surgery. Our aim was to study the dosimetric and implementation features/feasibility between IMRT and intensity-modulated arc radiotherapy (Varian RapidArc, Varian, Palo Alto, CA). The forward IMRT plan (f-IMRT), the inverse IMRT, and the RapidArc plan (RA) were generated for 10 patients. Afterward, we compared the target dose distribution of the 3 plans, radiation dose on organs at risk, monitor units, and treatment time. All 3 plans met clinical requirements, with RA performing best in target conformity. In target homogeneity, there was no statistical significance between RA and IMRT, but both of homogeneity were less than f-IMRT's. With regard to the V{sub 5} and V{sub 10} of the left lung, those in RA were higher than in f-IMRT but were lower than in IMRT; for V{sub 20} and V{sub 30}, the lowest was observed in RA; and in the V{sub 5} and V{sub 10} of the right lung, as well as the mean dose in normal-side breast and right lung, there was no statistically significance difference between RA and IMRT, and the lowest value was observed in f-IMRT. As for the maximum dose in the normal-side breast, the lowest value was observed in RA. Regarding monitor units (MUs), those in RA were higher than in f-IMRT but were lower than in IMRT. Treatment time of RA was 84.6% and 88.23% shorter than f-IMRT and IMRT, respectively, on average. Compared with f-IMRT and IMRT, RA performed better in target conformity and can reduce high-dose volume in the heart and left lung-which are related to complications-significantly shortening treatment time as well. Compared with IMRT, RA can also significantly reduce low-dose volume and MUs of the afflicted lung.

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

    SciTech Connect

    Kimura, Tomoki; Nishibuchi, Ikuno; Murakami, Yuji; Kenjo, Masahiro; Kaneyasu, Yuko; Nagata, Yasushi

    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.

  5. Improvement in toxicity in high risk prostate cancer patients treated with image-guided intensity-modulated radiotherapy compared to 3D conformal radiotherapy without daily image guidance

    PubMed Central

    2014-01-01

    Background Image-guided radiotherapy (IGRT) facilitates the delivery of a very precise radiation dose. In this study we compare the toxicity and biochemical progression-free survival between patients treated with daily image-guided intensity-modulated radiotherapy (IG-IMRT) and 3D conformal radiotherapy (3DCRT) without daily image guidance for high risk prostate cancer (PCa). Methods A total of 503 high risk PCa patients treated with radiotherapy (RT) and endocrine treatment between 2000 and 2010 were retrospectively reviewed. 115 patients were treated with 3DCRT, and 388 patients were treated with IG-IMRT. 3DCRT patients were treated to 76 Gy and without daily image guidance and with 1–2 cm PTV margins. IG-IMRT patients were treated to 78 Gy based on daily image guidance of fiducial markers, and the PTV margins were 5–7 mm. Furthermore, the dose-volume constraints to both the rectum and bladder were changed with the introduction of IG-IMRT. Results The 2-year actuarial likelihood of developing grade > = 2 GI toxicity following RT was 57.3% in 3DCRT patients and 5.8% in IG-IMRT patients (p < 0.001). For GU toxicity the numbers were 41.8% and 29.7%, respectively (p = 0.011). On multivariate analysis, 3DCRT was associated with a significantly increased risk of developing grade > = 2 GI toxicity compared to IG-IMRT (p < 0.001, HR = 11.59 [CI: 6.67-20.14]). 3DCRT was also associated with an increased risk of developing GU toxicity compared to IG-IMRT. The 3-year actuarial biochemical progression-free survival probability was 86.0% for 3DCRT and 90.3% for IG-IMRT (p = 0.386). On multivariate analysis there was no difference in biochemical progression-free survival between 3DCRT and IG-IMRT. Conclusion The difference in toxicity can be attributed to the combination of the IMRT technique with reduced dose to organs-at-risk, daily image guidance and margin reduction. PMID:24495815

  6. Proton Radiotherapy for Pediatric Bladder/Prostate Rhabdomyosarcoma: Clinical Outcomes and Dosimetry Compared to Intensity-Modulated Radiation Therapy

    SciTech Connect

    Cotter, Shane E.; Herrup, David A.; Friedmann, Alison; Macdonald, Shannon M.; Pieretti, Raphael V.; Robinson, Gregoire; Adams, Judith; Tarbell, Nancy J.; Yock, Torunn I.

    2011-12-01

    Purpose: In this study, we report the clinical outcomes of 7 children with bladder/prostate rhabdomyosarcoma (RMS) treated with proton radiation and compare proton treatment plans with matched intensity-modulated radiation therapy (IMRT) plans, with an emphasis on dose savings to reproductive and skeletal structures. Methods and Materials: Follow-up consisted of scheduled clinic appointments at our institution or direct communication with the treating physicians for referred patients. Each proton radiotherapy plan used for treatment was directly compared to an IMRT plan generated for the study. Clinical target volumes and normal tissue volumes were held constant to facilitate dosimetric comparisons. Each plan was optimized for target coverage and normal tissue sparing. Results: Seven male patients were treated with proton radiotherapy for bladder/prostate RMS at the Massachusetts General Hospital between 2002 and 2008. Median age at treatment was 30 months (11-70 months). Median follow-up was 27 months (10-90 months). Four patients underwent a gross total resection prior to radiation, and all patients received concurrent chemotherapy. Radiation doses ranged from 36 cobalt Gray equivalent (CGE) to 50.4 CGE. Five of 7 patients were without evidence of disease and with intact bladders at study completion. Target volume dosimetry was equivalent between the two modalities for all 7 patients. Proton radiotherapy led to a significant decrease in mean organ dose to the bladder (25.1 CGE vs. 33.2 Gy; p = 0.03), testes (0.0 CGE vs. 0.6 Gy; p = 0.016), femoral heads (1.6 CGE vs. 10.6 Gy; p = 0.016), growth plates (21.7 CGE vs. 32.4 Gy; p = 0.016), and pelvic bones (8.8 CGE vs. 13.5 Gy; p = 0.016) compared to IMRT. Conclusions: This study provides evidence of significant dose savings to normal structures with proton radiotherapy compared to IMRT and is well tolerated in this patient population. The long-term impact of these reduced doses can be tested in future studies

  7. Adenoid cystic carcinoma of the trachea treated with PET-CT based intensity modulated radiotherapy.

    PubMed

    Haresh, Kunhi Parambath; Prabhakar, Ramachandran; Rath, Goura K; Sharma, Daya Nand; Julka, Pramod K; Subramani, V

    2008-07-01

    Primary tumors of the trachea are rare and are usually malignant in adults and benign in children. Adenoid cystic carcinoma, which is of salivary gland origin, account for about one thirds of adult primary tracheal tumors. A 49-year-old gentleman presented to us after undergoing a pneumonectomy elsewhere. Computed tomography scan of the thorax at our hospital showed a residual disease in the primary site, size of which was same as that in the preoperative scan. Because there was a compromised respiratory reserve due to pneumonectomy we decided to keep the radiation dose to the remaining lung as low as possible. We treated him by positron emission tomography-computed tomography (PET-CT) directed intensity modulated radiation therapy to a dose of 60 Gy in 30 Fractions over 6 weeks on a linear accelerator. PET helped in exact localization of the target on the planning CT. He tolerated the treatment very well. PET-CT done 1 year posttreatment showed no residual disease. Presently he is disease free with good pulmonary reserve. PMID:18594327

  8. Analysis of Factors Influencing the Development of Xerostomia during Intensity-Modulated Radiotherapy

    PubMed Central

    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

  9. Radiochromic film based transit dosimetry for verification of dose delivery with intensity modulated radiotherapy

    SciTech Connect

    Chung, Kwangzoo; Lee, Kiho; Shin, Dongho; Kyung Lim, Young; Byeong Lee, Se; Yoon, Myonggeun; Son, Jaeman; Yong Park, Sung

    2013-02-15

    Purpose: To evaluate the transit dose based patient specific quality assurance (QA) of intensity modulated radiation therapy (IMRT) for verification of the accuracy of dose delivered to the patient. Methods: Five IMRT plans were selected and utilized to irradiate a homogeneous plastic water phantom and an inhomogeneous anthropomorphic phantom. The transit dose distribution was measured with radiochromic film and was compared with the computed dose map on the same plane using a gamma index with a 3% dose and a 3 mm distance-to-dose agreement tolerance limit. Results: While the average gamma index for comparisons of dose distributions was less than one for 98.9% of all pixels from the transit dose with the homogeneous phantom, the passing rate was reduced to 95.0% for the transit dose with the inhomogeneous phantom. Transit doses due to a 5 mm setup error may cause up to a 50% failure rate of the gamma index. Conclusions: Transit dose based IMRT QA may be superior to the traditional QA method since the former can show whether the inhomogeneity correction algorithm from TPS is accurate. In addition, transit dose based IMRT QA can be used to verify the accuracy of the dose delivered to the patient during treatment by revealing significant increases in the failure rate of the gamma index resulting from errors in patient positioning during treatment.

  10. Can Intensity-Modulated Radiotherapy Preserve Oral Health-Related Quality of Life of Nasopharyngeal Carcinoma Patients?

    SciTech Connect

    Pow, Edmond H.N.; Kwong, Dora L.W.; Sham, Jonathan S.T.; Lee, Victor H.F.; Ng, Sherry C.Y.

    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.

  11. Multivariate analysis of factors predicting prostate dose in intensity-modulated radiotherapy

    SciTech Connect

    Tomita, Tsuneyuki; Nakamura, Mitsuhiro; Hirose, Yoshinori; Kitsuda, Kenji; Notogawa, Takuya; Miki, Katsuhito; Nakamura, Kiyonao; Ishigaki, Takashi

    2014-01-01

    We conducted a multivariate analysis to determine relationships between prostate radiation dose and the state of surrounding organs, including organ volumes and the internal angle of the levator ani muscle (LAM), based on cone-beam computed tomography (CBCT) images after bone matching. We analyzed 270 CBCT data sets from 30 consecutive patients receiving intensity-modulated radiation therapy for prostate cancer. With patients in the supine position on a couch with the HipFix system, data for center of mass (COM) displacement of the prostate and the state of individual organs were acquired and compared between planning CT and CBCT scans. Dose distributions were then recalculated based on CBCT images. The relative effects of factors on the variance in COM, dose covering 95% of the prostate volume (D{sub 95%}), and percentage of prostate volume covered by the 100% isodose line (V{sub 100%}) were evaluated by a backward stepwise multiple regression analysis. COM displacement in the anterior-posterior direction (COM{sub AP}) correlated significantly with the rectum volume (δVr) and the internal LAM angle (δθ; R = 0.63). Weak correlations were seen for COM in the left-right (R = 0.18) and superior-inferior directions (R = 0.31). Strong correlations between COM{sub AP} and prostate D{sub 95%} and V{sub 100%} were observed (R ≥ 0.69). Additionally, the change ratios in δVr and δθ remained as predictors of prostate D{sub 95%} and V{sub 100%}. This study shows statistically that maintaining the same rectum volume and LAM state for both the planning CT simulation and treatment is important to ensure the correct prostate dose in the supine position with bone matching.

  12. Intensity-modulated radiotherapy (IMRT) and conventional three-dimensional conformal radiotherapy for high-grade gliomas: Does IMRT increase the integral dose to normal brain?

    SciTech Connect

    Hermanto, Ulrich; Frija, Erik K.; Lii, MingFwu J.; Chang, Eric L.; Mahajan, Anita; Woo, Shiao Y. . E-mail: SYWoo@mdanderson.org

    2007-03-15

    Purpose: To determine whether intensity-modulated radiotherapy (IMRT) treatment increases the total integral dose of nontarget tissue relative to the conventional three-dimensional conformal radiotherapy (3D-CRT) technique for high-grade gliomas. Methods and Materials: Twenty patients treated with 3D-CRT for glioblastoma multiforme were selected for a comparative dosimetric evaluation with IMRT. Original target volumes, organs at risk (OAR), and dose-volume constraints were used for replanning with IMRT. Predicted isodose distributions, cumulative dose-volume histograms of target volumes and OAR, normal tissue integral dose, target coverage, dose conformity, and normal tissue sparing with 3D-CRT and IMRT planning were compared. Statistical analyses were performed to determine differences. Results: In all 20 patients, IMRT maintained equivalent target coverage, improved target conformity (conformity index [CI] 95% 1.52 vs. 1.38, p < 0.001), and enabled dose reductions of normal tissues, including brainstem (D{sub mean} by 19.8% and D{sub max} by 10.7%), optic chiasm (D{sub mean} by 25.3% and D{sub max} by 22.6%), right optic nerve (D{sub mean} by 37.3% and D{sub max} by 28.5%), and left optic nerve (D{sub mean} by 40.6% and D{sub max} by 36.7%), p {<=} 0.01. This was achieved without increasing the total nontarget integral dose by greater than 0.5%. Overall, total integral dose was reduced by 7-10% with IMRT, p < 0.001, without significantly increasing the 0.5-5 Gy low-dose volume. Conclusions: These results indicate that IMRT treatment for high-grade gliomas allows for improved target conformity, better critical tissue sparing, and importantly does so without increasing integral dose and the volume of normal tissue exposed to low doses of radiation.

  13. Dosimetric comparison between intensity-modulated radiotherapy and standard wedged tangential technique for whole-breast radiotherapy in Asian women with relatively small breast volumes.

    PubMed

    Tsuchiya, Kazuhiko; Kinoshita, Rumiko; Shimizu, Shinichi; Nishioka, Kentaro; Harada, Keiichi; Nishikawa, Noboru; Suzuki, Ryusuke; Shirato, Hiroki

    2014-01-01

    We sought to investigate whether intensity-modulated radiotherapy (IMRT) has a dosimetric advantage compared to the standard wedged tangential technique (SWT) for whole-breast radiotherapy (WBRT) in Asian women with relatively small breast volume. Computed tomography images of 25 Asian patients with early-stage breast cancer (right 15, left 10) used for WBRT planning were examined. After contouring the target volumes and bilateral lungs and, for left-side treatment, the heart, 4 plans were made for each patient: namely, SWT, tangential-field IMRT (T-IMRT), 3-field IMRT (3F-IMRT), and 4-field IMRT (4F-IMRT). The prescribed dose was 5000 cGy. The median planning target volume (PTV) for WBRT was 552.6 cc (range 288.8-1518.4 cc). Compared to SWT, (1) T-IMRT achieved significant improvement for dose homogeneity in the PTV (p < 0.001) and the dose received by 2% (D2) of the PTV (p < 0.001). T-IMRT also reduced the bilateral lung mean dose (p < 0.001) and the ipsilateral lung volume which received more than 20 Gy (V20) (p = 0.01). (2) 3F-IMRT resulted in a significant increase in the mean dose to the ipsilateral lung (p < 0.001) and to the contralateral lung (p < 0.001). (3) 4F-IMRT also resulted in a significant increase in the mean dose to the ipsilateral lung (p < 0.001) and to the contralateral lung (p < 0.001). Tangential-field IMRT provided an improved dose distribution compared with SWT for WBRT in Asian women with a relatively small breast volume.

  14. Quality of Life and Survival Outcome for Patients With Nasopharyngeal Carcinoma Receiving Three-Dimensional Conformal Radiotherapy vs. Intensity-Modulated Radiotherapy-A Longitudinal Study

    SciTech Connect

    Fang, F.-M. Chien, C.-Y.; Tsai, W.-L.; Chen, H.-C.; Hsu, H.-C.; Lui, C.-C.; Huang, T.-L.

    2008-10-01

    Purpose: To investigate the changes of quality of life (QoL) and survival outcomes for patients with nasopharyngeal carcinoma (NPC) treated by three-dimensional conformal radiotherapy (3D-CRT) vs. intensity-modulated radiotherapy (IMRT). Methods and Materials: Two hundred and three newly diagnosed NPC patients, who were curatively treated by 3D-CRT (n = 93) or IMRT (n = 110) between March 2002 and July 2004, were analyzed. The distributions of clinical stage according to American Joint Committee on Cancer 1997 were I: 15 (7.4%), II: 78 (38.4%), III: 74 (36.5%), and IV: 36 (17.7%). QoL was longitudinally assessed by the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30 and the EORTC QLQ-H and N35 questionnaires at the five time points: before RT, during RT (36 Gy), and 3 months, 12 months, and 24 months after RT. Results: The 3-year locoregional control, metastasis-free survival, and overall survival rates were 84.8%, 76.7%, and 81.7% for the 3D-CRT group, respectively, compared with 84.2%, 82.6%, and 85.4% for the IMRT group (p value > 0.05). A general trend of maximal deterioration in most QoL scales was observed during RT, followed by a gradual recovery thereafter. There was no significant difference in most scales between the two groups at each time point. The exception was that patients treated by IMRT had a both statistically and clinically significant improvement in global QoL, fatigue, taste/smell, dry mouth, and feeling ill at the time point of 3 months after RT. Conclusions: The potential advantage of IMRT over 3D-CRT in treating NPC patients might occur in QoL outcome during the recovery phase of acute toxicity.

  15. Dosimetric Comparison of Combined Intensity-Modulated Radiotherapy (IMRT) and Proton Therapy Versus IMRT Alone for Pelvic and Para-Aortic Radiotherapy in Gynecologic Malignancies

    SciTech Connect

    Berman Milby, Abigail; Both, Stefan; Ingram, Mark; Lin, Lilie L.

    2012-03-01

    Purpose: To perform a dosimetric comparison of intensity-modulated radiotherapy (IMRT), passive scattering proton therapy (PSPT), and intensity-modulated proton therapy (IMPT) to the para-aortic (PA) nodal region in women with locally advanced gynecologic malignancies. Methods and Materials: The CT treatment planning scans of 10 consecutive patients treated with IMRT to the pelvis and PA nodes were identified. The clinical target volume was defined by the primary tumor for patients with cervical cancer and by the vagina and paravaginal tissues for patients with endometrial cancer, in addition to the regional lymph nodes. The IMRT, PSPT, and IMPT plans were generated using the Eclipse Treatment Planning System and were analyzed for various dosimetric endpoints. Two groups of treatment plans including proton radiotherapy were created: IMRT to pelvic nodes with PSPT to PA nodes (PSPT/IMRT), and IMRT to pelvic nodes with IMPT to PA nodes (IMPT/IMRT). The IMRT and proton RT plans were optimized to deliver 50.4 Gy or Gy (relative biologic effectiveness [RBE)), respectively. Dose-volume histograms were analyzed for all of the organs at risk. The paired t test was used for all statistical comparison. Results: The small-bowel V{sub 20}, V{sub 30}, V{sub 35}, andV{sub 40} were reduced in PSPT/IMRT by 11%, 18%, 27%, and 43%, respectively (p < 0.01). Treatment with IMPT/IMRT demonstrated a 32% decrease in the small-bowel V{sub 20}. Treatment with PSPT/IMRT showed statistically significant reductions in the body V{sub 5-20}; IMPT/IMRT showed reductions in the body V{sub 5-15}. The dose received by half of both kidneys was reduced by PSPT/IMRT and by IMPT/IMRT. All plans maintained excellent coverage of the planning target volume. Conclusions: Compared with IMRT alone, PSPT/IMRT and IMPT/IMRT had a statistically significant decrease in dose to the small and large bowel and kidneys, while maintaining excellent planning target volume coverage. Further studies should be done to

  16. Dosimetric and radiobiologic comparison of 3D conformal versus intensity modulated planning techniques for prostate bed radiotherapy.

    PubMed

    Koontz, Bridget F; Das, Shiva; Temple, Kathy; Bynum, Sigrun; Catalano, Suzanne; Koontz, Jason I; Montana, Gustavo S; Oleson, James R

    2009-01-01

    Adjuvant radiotherapy for locally advanced prostate cancer improves biochemical and clinical disease-free survival. While comparisons in intact prostate cancer show a benefit for intensity modulated radiation therapy (IMRT) over 3D conformal planning, this has not been studied for post-prostatectomy radiotherapy (RT). This study compares normal tissue and target dosimetry and radiobiological modeling of IMRT vs. 3D conformal planning in the postoperative setting. 3D conformal plans were designed for 15 patients who had been treated with IMRT planning for salvage post-prostatectomy RT. The same computed tomography (CT) and target/normal structure contours, as well as prescription dose, was used for both IMRT and 3D plans. Normal tissue complication probabilities (NTCPs) were calculated based on the dose given to the bladder and rectum by both plans. Dose-volume histogram and NTCP data were compared by paired t-test. Bladder and rectal sparing were improved with IMRT planning compared to 3D conformal planning. The volume of the bladder receiving at least 75% (V75) and 50% (V50) of the dose was significantly reduced by 28% and 17%, respectively (p = 0.002 and 0.037). Rectal dose was similarly reduced, V75 by 33% and V50 by 17% (p = 0.001 and 0.004). While there was no difference in the volume of rectum receiving at least 65 Gy (V65), IMRT planning significant reduced the volume receiving 40 Gy or more (V40, p = 0.009). Bladder V40 and V65 were not significantly different between planning modalities. Despite these dosimetric differences, there was no significant difference in the NTCP for either bladder or rectal injury. IMRT planning reduces the volume of bladder and rectum receiving high doses during post-prostatectomy RT. Because of relatively low doses given to the bladder and rectum, there was no statistically significant improvement in NTCP between the 3D conformal and IMRT plans.

  17. Parotid Gland Dose in Intensity-Modulated Radiotherapy for Head and Neck Cancer: Is What You Plan What You Get?

    SciTech Connect

    O'Daniel, Jennifer C.; Garden, Adam S.; Schwartz, David L.; Wang He; Ang, Kian K.; Ahamad, Anesa; Rosenthal, David I.; Morrison, William H.; Asper, Joshua A.; Zhang Lifei; Tung Shihming; Mohan, Radhe; Dong Lei

    2007-11-15

    Purpose: To quantify the differences between planned and delivered parotid gland and target doses, and to assess the benefits of daily bone alignment for head and neck cancer patients treated with intensity-modulated radiotherapy (IMRT). Methods and Materials: Eleven head and neck cancer patients received two CT scans per week with an in-room CT scanner over the course of their radiotherapy. The clinical IMRT plans, designed with 3-mm to 4-mm planning margins, were recalculated on the repeat CT images. The plans were aligned using the actual treatment isocenter marked with radiopaque markers (BB) and bone alignment to the cervical vertebrae to simulate image-guided setup. In-house deformable image registration software was used to map daily dose distributions to the original treatment plan and to calculate a cumulative delivered dose distribution for each patient. Results: Using conventional BB alignment led to increases in the parotid gland mean dose above the planned dose by 5 to 7 Gy in 45% of the patients (median, 3.0 Gy ipsilateral, p = 0.026; median, 1.0 Gy contralateral, p = 0.016). Use of bone alignment led to reductions relative to BB alignment in 91% of patients (median, 2 Gy; range, 0.3-8.3 Gy; 15 of 22 parotids improved). However, the parotid dose from bone alignment was still greater than planned (median, 1.0 Gy, p = 0.007). Neither approach affected tumor dose coverage. Conclusions: With conventional BB alignment, the parotid gland mean dose was significantly increased above the planned mean dose. Using daily bone alignment reduced the parotid dose compared with BB alignment in almost all patients. A 3- to 4-mm planning margin was adequate for tumor dose coverage.

  18. Dosimetric Comparison of Intensity-Modulated Stereotactic Radiotherapy With Other Stereotactic Techniques for Locally Recurrent Nasopharyngeal Carcinoma

    SciTech Connect

    Kung, Shiris Wai Sum; Wu, Vincent Wing Cheung; Kam, Michael Koon Ming; Leung, Sing Fai; Yu, Brian Kwok Hung; Ngai, Dennis Yuen Kan; Wong, Simon Chun Fai; Chan, Anthony Tak Cheung

    2011-01-01

    Purpose: Locally recurrent nasopharyngeal carcinoma (NPC) patients can be salvaged by reirradiation with a substantial degree of radiation-related complications. Stereotactic radiotherapy (SRT) is widely used in this regard because of its rapid dose falloff and high geometric precision. The aim of this study was to examine whether the newly developed intensity-modulated stereotactic radiotherapy (IMSRT) has any dosimetric advantages over three other stereotactic techniques, including circular arc (CARC), static conformal beam (SmMLC), and dynamic conformal arc (mARC), in treating locally recurrent NPC. Methods and Materials: Computed tomography images of 32 patients with locally recurrent NPC, previously treated with SRT, were retrieved from the stereotactic planning system for contouring and computing treatment plans. Treatment planning of each patient was performed for the four treatment techniques: CARC, SmMLC, mARC, and IMSRT. The conformity index (CI) and homogeneity index (HI) of the planning target volume (PTV) and doses to the organs at risk (OARs) and normal tissue were compared. Results: All four techniques delivered adequate doses to the PTV. IMSRT, SmMLC, and mARC delivered reasonably conformal and homogenous dose to the PTV (CI <1.47, HI <0.53), but not for CARC (p < 0.05). IMSRT presented with the smallest CI (1.37) and HI (0.40). Among the four techniques, IMSRT spared the greatest number of OARs, namely brainstem, temporal lobes, optic chiasm, and optic nerve, and had the smallest normal tissue volume in the low-dose region. Conclusion: Based on the dosimetric comparison, IMSRT was optimal for locally recurrent NPC by delivering a conformal and homogenous dose to the PTV while sparing OARs.

  19. Dose differences in intensity-modulated radiotherapy plans calculated with pencil beam and Monte Carlo for lung SBRT.

    PubMed

    Liu, Han; Zhuang, Tingliang; Stephans, Kevin; Videtic, Gregory; Raithel, Stephen; Djemil, Toufik; Xia, Ping

    2015-11-08

    For patients with medically inoperable early-stage non-small cell lung cancer (NSCLC) treated with stereotactic body radiation therapy, early treatment plans were based on a simpler dose calculation algorithm, the pencil beam (PB) calculation. Because these patients had the longest treatment follow-up, identifying dose differences between the PB calculated dose and Monte Carlo calculated dose is clinically important for understanding of treatment outcomes. Previous studies found significant dose differences between the PB dose calculation and more accurate dose calculation algorithms, such as convolution-based or Monte Carlo (MC), mostly for three-dimensional conformal radiotherapy (3D CRT) plans. The aim of this study is to investigate whether these observed dose differences also exist for intensity-modulated radiotherapy (IMRT) plans for both centrally and peripherally located tumors. Seventy patients (35 central and 35 peripheral) were retrospectively selected for this study. The clinical IMRT plans that were initially calculated with the PB algorithm were recalculated with the MC algorithm. Among these paired plans, dosimetric parameters were compared for the targets and critical organs. When compared to MC calculation, PB calculation overestimated doses to the planning target volumes (PTVs) of central and peripheral tumors with different magnitudes. The doses to 95% of the central and peripheral PTVs were overestimated by 9.7% ± 5.6% and 12.0% ± 7.3%, respectively. This dose overestimation did not affect doses to the critical organs, such as the spinal cord and lung. In conclusion, for NSCLC treated with IMRT, dose differences between the PB and MC calculations were different from that of 3D CRT. No significant dose differences in critical organs were observed between the two calculations.

  20. Improved Dosimetric and Clinical Outcomes With Intensity-Modulated Radiotherapy for Head-and-Neck Cancer of Unknown Primary Origin

    SciTech Connect

    Chen, Allen M.; Li Baoqing; Farwell, D. Gregory; Marsano, Joseph; Vijayakumar, Srinivasan; Purdy, James A.

    2011-03-01

    Purpose: To compare differences in dosimetric, clinical, and quality-of-life endpoints among a cohort of patients treated by intensity-modulated radiotherapy (IMRT) and conventional radiotherapy (CRT) for head-and-neck cancer of unknown primary origin. Methods and Materials: The medical records of 51 patients treated by radiation therapy for squamous cell carcinoma of the head and neck presenting as cervical lymph node metastasis of occult primary origin were reviewed. Twenty-four patients (47%) were treated using CRT, and 27 (53%) were treated using IMRT. The proportions of patients receiving concurrent chemotherapy were 54% and 63%, respectively. Results: The 2-year estimates of overall survival, local-regional control, and disease-specific survival for the entire patient population were 86%, 89%, and84%, respectively. There were no significant differences in any of these endpoints with respect to radiation therapy technique (p > 0.05 for all). Dosimetric analysis revealed that the use of IMRT resulted in significant improvements with respect to mean dose and V30 to the contralateral (spared) parotid gland. In addition, mean doses to the ipsilateral inner and middle ear structures were significantly reduced with IMRT (p < 0.05 for all). The incidence of severe xerostomia in the late setting was 58% and 11% among patients treated by CRT and IMRT, respectively (p < 0.001). The percentages of patients who were G-tube dependent at 6 months after treatment were 42% and 11%, respectively (p < 0.001). Conclusions: IMRT results in significant improvements in the therapeutic ratio among patients treated by radiation therapy for head-and-neck cancer of unknown primary origin.

  1. Randomized Controlled Trial of Forward-Planned Intensity Modulated Radiotherapy for Early Breast Cancer: Interim Results at 2 Years

    SciTech Connect

    Barnett, Gillian C.; Wilkinson, Jennifer S.; Moody, Anne M.; Wilson, Charles B.; Twyman, Nicola; Wishart, Gordon C.; Burnet, Neil G.; Coles, Charlotte E.

    2012-02-01

    Purpose: This single-center randomized trial was designed to investigate whether intensity-modulated radiotherapy (IMRT) reduces late toxicity in patients with early-stage breast cancer. Methods and Materials: The standard tangential plans of 1,145 nonselected patients were analyzed. The patients with inhomogeneous plans were randomized to a simple method of forward-planned IMRT or standard radiotherapy (RT). The primary endpoint was serial photographic assessment of breast shrinkage. Results: At 2 years, no significant difference was found in the development of any photographically assessed breast shrinkage between the patients randomized to the interventional or control group (odds ratio, 1.51; 95% confidence interval, 0.83-1.58; p = .41). The patients in the control group were more likely to develop telangiectasia than those in the IMRT group (odds ratio, 1.68; 95% confidence interval 1.13-2.40; p = .009). Poor baseline surgical cosmesis resulted in poor overall cosmesis at 2 years after RT. In patients who had good surgical cosmesis, those randomized to IMRT were less likely to deteriorate to a moderate or poor overall cosmesis than those in the control group (odds ratio, 0.63; 95% confidence interval, 0.39-1.03, p = .061). Conclusions: IMRT can lead to a significant reduction in telangiectasia at comparatively early follow-up of only 2 years after RT completion. An important component of breast induration and shrinkage will actually result from the surgery and not from the RT. Surgical cosmesis is an important determinant of overall cosmesis and could partially mask the longer term benefits of IMRT at this early stage.

  2. Intensity-Modulated Radiotherapy of Pelvic Lymph Nodes in Locally Advanced Prostate Cancer: Planning Procedures and Early Experiences

    SciTech Connect

    Muren, Ludvig Paul Wasbo, Ellen; Helle, Svein Inge; Hysing, Liv Bolstad; Karlsdottir, Asa; Odland, Odd Harald; Valen, Harald; Ekerold, Randi; Johannessen, Dag Clement

    2008-07-15

    Purpose: We present planning and early clinical outcomes of a study of intensity-modulated radiotherapy (IMRT) for locally advanced prostate cancer. Methods and Materials: A total of 43 patients initially treated with an IMRT plan delivering 50 Gy to the prostate, seminal vesicles, and pelvic lymph nodes, followed by a conformal radiotherapy (CRT) plan delivering 20 Gy to the prostate and seminal vesicles, were studied. Dose-volume histogram (DVH) data for the added plans were compared with dose-volume histogram data for the sum of two CRT plans for 15 cases. Gastrointestinal (GI) and genitourinary (GU) toxicity, based on the Radiation Therapy Oncology Group scoring system, was recorded weekly throughout treatment as well as 3 to 18 months after treatment and are presented. Results: Treatment with IMRT both reduced normal tissue doses and increased the minimum target doses. Intestine volumes receiving more than 40 and 50 Gy were significantly reduced (e.g., at 50 Gy, from 81 to 19 cm{sup 3}; p = 0.026), as were bladder volumes above 40, 50, and 60 Gy, rectum volumes above 30, 50, and 60 Gy, and hip joint muscle volumes above 20, 30, and 40 Gy. During treatment, Grade 2 GI toxicity was reported by 12 of 43 patients (28%), and Grade 2 to 4 GU toxicity was also observed among 12 patients (28%). With 6 to 18 months of follow-up, 2 patients (5%) experienced Grade 2 GI effects and 7 patients (16%) experienced Grade 2 GU effects. Conclusions: Use of IMRT for pelvic irradiation in prostate cancer reduces normal tissue doses, improves target coverage, and has a promising toxicity profile.

  3. Effect of Intensity-Modulated Pelvic Radiotherapy on Second Cancer Risk in the Postoperative Treatment of Endometrial and Cervical Cancer

    SciTech Connect

    Zwahlen, Daniel R. Ruben, Jeremy D.; Jones, Phillip; Gagliardi, Frank; Millar, Jeremy L.; Schneider, Uwe

    2009-06-01

    Purpose: To estimate and compare intensity-modulated radiotherapy (IMRT) with three-dimensional conformal radiotherapy (3DCRT) in terms of second cancer risk (SCR) for postoperative treatment of endometrial and cervical cancer. Methods and Materials: To estimate SCR, the organ equivalent dose concept with a linear-exponential, a plateau, and a linear dose-response model was applied to dose distributions, calculated in a planning computed tomography scan of a 68-year-old woman. Three plans were computed: four-field 18-MV 3DCRT and nine-field IMRT with 6- and 18-MV photons. SCR was estimated as a function of target dose (50.4 Gy/28 fractions) in organs of interest according to the International Commission on Radiological Protection Results: Cumulative SCR relative to 3DCRT was +6% (3% for a plateau model, -4% for a linear model) for 6-MV IMRT and +26% (25%, 4%) for the 18-MV IMRT plan. For an organ within the primary beam, SCR was +12% (0%, -12%) for 6-MV and +5% (-2%, -7%) for 18-MV IMRT. 18-MV IMRT increased SCR 6-7 times for organs away from the primary beam relative to 3DCRT and 6-MV IMRT. Skin SCR increased by 22-37% for 6-MV and 50-69% for 18-MV IMRT inasmuch as a larger volume of skin was exposed. Conclusion: Cancer risk after IMRT for cervical and endometrial cancer is dependent on treatment energy. 6-MV pelvic IMRT represents a safe alternative with respect to SCR relative to 3DCRT, independently of the dose-response model. 18-MV IMRT produces second neutrons that modestly increase the SCR.

  4. Efficacy and Toxicity of Chemoradiotherapy Using Intensity-Modulated Radiotherapy for Unknown Primary of Head and Neck

    SciTech Connect

    Sher, David J.; Balboni, Tracy A.; Haddad, Robert I.; Norris, Charles M.; Posner, Marshall R.; Wirth, Lori J.; Goguen, Laura A.; Annino, Donald; Tishler, Roy B.

    2011-08-01

    Purpose: No single standard treatment paradigm is available for head-and-neck squamous cell carcinoma of an unknown primary (HNCUP). Bilateral neck radiotherapy with mucosal axis irradiation is widely used, with or without chemotherapy and/or surgical resection. Intensity-modulated radiotherapy (IMRT) is a highly conformal method for delivering radiation that is becoming the standard of care and might reduce the long-term treatment-related sequelae. We report the Dana-Farber Cancer Institute experience with IMRT-based treatment for HNCUP. Patients and Materials: A retrospective study of all patients treated at the Dana-Farber Cancer Institute for HNCUP with IMRT between August 2004 and January 2009. The primary endpoint was overall survival; the secondary endpoints were locoregional and distant control, and acute and chronic toxicity. Results: A total of 24 patients with HNCUP were included. Of these patients, 22 had Stage N2 disease or greater. All patients underwent neck computed tomography, positron emission tomography-computed tomography, and examination under anesthesia with directed biopsies. Of the 24 patients, 22 received concurrent chemotherapy, and 7 (29%) also underwent induction chemotherapy. The median involved nodal dose was 70 Gy, and the median mucosal dose was 60 Gy. With a median follow-up of 2.1 years, the 2-year actuarial overall survival and locoregional control rate was 92% and 100%, respectively. Only 25% of the patients had Grade 2 xerostomia, although 11 patients (46%) required esophageal dilation for stricture. Conclusion: In a single-institution series, IMRT-based chemoradiotherapy for HNCUP was associated with superb overall survival and locoregional control. The xerostomia rates were promising, but the aggressive therapy was associated with significant rates of esophageal stenosis.

  5. Clinical-dosimetric relationship between lacrimal gland dose and ocular toxicity after intensity-modulated radiotherapy for sinonasal tumours

    PubMed Central

    Batth, S S; Sreeraman, R; Dienes, E; Beckett, L A; Daly, M E; Cui, J; Mathai, M; Purdy, J A

    2013-01-01

    Objective: To characterise the relationship between lacrimal gland dose and ocular toxicity among patients treated by intensity-modulated radiotherapy (IMRT) for sinonasal tumours. Methods: 40 patients with cancers involving the nasal cavity and paranasal sinuses were treated with IMRT to a median dose of 66.0 Gy. Toxicity was scored using the Radiation Therapy Oncology Group morbidity criteria based on conjunctivitis, corneal ulceration and keratitis. The paired lacrimal glands were contoured as organs at risk, and the mean dose, maximum dose, V10, V20 and V30 were determined. Statistical analysis was performed using logistic regression and the Akaike information criterion (AIC). Results: The maximum and mean dose to the ipsilateral lacrimal gland were 19.2 Gy (range, 1.4–75.4 Gy) and 14.5 Gy (range, 11.1–67.8 Gy), respectively. The mean V10, V20 and V30 values were 50%, 25% and 17%, respectively. The incidence of acute and late Grade 3+ toxicities was 23% and 19%, respectively. Based on logistic regression and AIC, the maximum dose to the ipsilateral lacrimal gland was identified as a more significant predictor of acute toxicity (AIC, 53.89) and late toxicity (AIC, 32.94) than the mean dose (AIC, 56.13 and 33.83, respectively). The V20 was identified as the most significant predictor of late toxicity (AIC, 26.81). Conclusion: A dose–response relationship between maximum dose to the lacrimal gland and ocular toxicity was established. Our data suggesting a threshold relationship may be useful in establishing dosimetric guidelines for IMRT planning that may decrease the risk of acute and late lacrimal toxicities in the future. Advances in knowledge: A threshold relationship between radiation dose to the lacrimal gland and ocular toxicity was demonstrated, which may aid in treatment planning and reducing the morbidity of radiotherapy for sinonasal tumours. PMID:24167183

  6. Grading xerostomia by physicians or by patients after intensity-modulated radiotherapy of head-and-neck cancer

    SciTech Connect

    Meirovitz, Amichay; Murdoch-Kinch, Carol Anne; Schipper, Mathew; Pan, Charlie; Eisbruch, Avraham . E-mail: eisbruch@umich.edu

    2006-10-01

    Purpose: To assess observer-based vs. patient self-reported scoring of xerostomia after intensity-modulated radiotherapy (IMRT) of head-and-neck (HN) cancer. Methods: A total of 38 patients who had received IMRT for HN cancer underwent xerostomia evaluations 6 to 24 months after completion of therapy using three methods each time: (1) Grading by 3 observers according to the Radiotherapy Oncology Group/European Organization for Research and Therapy of Cancer (RTOG/EORTC) system; (2) patient self-reported validated xerostomia questionnaire (XQ); and (3) major salivary gland flow measurements. Results: The interobserver agreement regarding the RTOG/EORTC grades was moderate: {kappa}-coefficient 0.54 (95% CI = 0.31-0.76). The correlations between the average RTOG/EORTC grades and the salivary flow rates were not statistically significant. A trend for significant correlation was observed between these grades and the percent (relative to the pretherapy) nonstimulated salivary flow rates (p = 0.07), but not with the percent stimulated flow rates. Better correlations were found between grading made more than the median time (15 min) after the last liquid sipping and the nonstimulated (but not the stimulated) flows compared with grading made shortly after sipping. In contrast, significant correlations were found between the XQ scores and the nonstimulated (p < 0.005) and the stimulated (p < 0.005) salivary flow rates, as well as with the percentages of the corresponding pretherapy values (p = 0.002 and 0.038, respectively). No significant correlation was found between the RTOG/EORTC grades and the XQ scores. The observer-based grades underestimated the severity of xerostomia compared with the patient self-reported scores. Conclusions: Patient self-reported, rather than physician-assessed scores, should be the main end points in evaluating xerostomia.

  7. Dose-Effect Relationships for the Submandibular Salivary Glands and Implications for Their Sparing by Intensity Modulated Radiotherapy

    SciTech Connect

    Murdoch-Kinch, Carol-Anne; Vineberg, Karen A.; Ship, Jonathan

    2008-10-01

    Purpose: Submandibular salivary glands (SMGs) dysfunction contributes to xerostomia after radiotherapy (RT) of head-and-neck (HN) cancer. We assessed SMG dose-response relationships and their implications for sparing these glands by intensity-modulated radiotherapy (IMRT). Methods and Materials: A total of 148 HN cancer patients underwent unstimulated and stimulated SMG salivary flow rate measurements selectively from Wharton's duct orifices, before RT and periodically through 24 months after RT. Correlations of flow rates and mean SMG doses were modeled throughout all time points. IMRT replanning in 8 patients whose contralateral level I was not a target incorporated the results in a new cost function aiming to spare contralateral SMGs. Results: Stimulated SMG flow rates decreased exponentially by (1.2%){sup Gy} as mean doses increased up to 39 Gy threshold, and then plateaued near zero. At mean doses {<=}39 Gy, but not higher, flow rates recovered over time at 2.2%/month. Similarly, the unstimulated salivary flow rates decreased exponentially by (3%){sup Gy} as mean dose increased and recovered over time if mean dose was <39 Gy. IMRT replanning reduced mean contralateral SMG dose by average 12 Gy, achieving {<=}39 Gy in 5 of 8 patients, without target underdosing, increasing the mean doses to the parotid glands and swallowing structures by average 2-3 Gy. Conclusions: SMG salivary flow rates depended on mean dose with recovery over time up to a threshold of 39 Gy. Substantial SMG dose reduction to below this threshold and without target underdosing is feasible in some patients, at the expense of modestly higher doses to some other organs.

  8. Dose-Effect Relationships for the Submandibular Salivary Glands and Implications for Their Sparing by Intensity Modulated Radiotherapy

    PubMed Central

    Murdoch-Kinch, Carol-Anne; Kim, Hyugnjin M.; Vineberg, Karen A; Ship, Jonathan A.; Eisbruch, Avraham

    2012-01-01

    Purpose Submandibular salivary glands (SMGs) dysfunction contributes to xerostomia after radiotherapy (RT) of head and neck (HN) cancer. We assessed SMG dose-response relationships and their implications for sparing these glands by intensity modulated radiotherapy (IMRT). Patients and Methods 148 HN cancer patients underwent unstimulated and stimulated SMG salivary flow rate measurements selectively from Wharton’s duct orifices, before RT and periodically through 24 months after RT. Correlations of flow rates and mean SMG doses were modeled throughout all time points. IMRT re-planning in eight patients whose contralateral level I was not a target incorporated the results in a new cost function aiming to spare contralateral SMGs. Results Stimulated SMG flow rates decreased exponentially by (1.2%)Gy as mean doses increased up to 39 Gy threshold, and then plateaued near zero. At mean doses ≤39 Gy, but not higher, flow rates recovered over time at 2.2%/month. Similarly, the unstimulated salivary flow rates decreased exponentially by (3%)Gy as mean dose increased and recovered over time if mean dose was <39 Gy. IMRT re-planning reduced mean contralateral SMG dose by average 12 Gy, achieving ≤39 Gy in 5/8 patients, without target under-dosing, increasing the mean doses to the parotid glands and swallowing structures by average 2–3 Gy. Conclusions SMG salivary flow rates depended on mean dose with recovery over time up to a threshold of 39 Gy. Substantial SMG dose reduction to below this threshold and without target under-dosing is feasible in some patients, at the expense of modestly higher doses to some other organs. PMID:18337023

  9. Dose differences in intensity-modulated radiotherapy plans calculated with pencil beam and Monte Carlo for lung SBRT.

    PubMed

    Liu, Han; Zhuang, Tingliang; Stephans, Kevin; Videtic, Gregory; Raithel, Stephen; Djemil, Toufik; Xia, Ping

    2015-01-01

    For patients with medically inoperable early-stage non-small cell lung cancer (NSCLC) treated with stereotactic body radiation therapy, early treatment plans were based on a simpler dose calculation algorithm, the pencil beam (PB) calculation. Because these patients had the longest treatment follow-up, identifying dose differences between the PB calculated dose and Monte Carlo calculated dose is clinically important for understanding of treatment outcomes. Previous studies found significant dose differences between the PB dose calculation and more accurate dose calculation algorithms, such as convolution-based or Monte Carlo (MC), mostly for three-dimensional conformal radiotherapy (3D CRT) plans. The aim of this study is to investigate whether these observed dose differences also exist for intensity-modulated radiotherapy (IMRT) plans for both centrally and peripherally located tumors. Seventy patients (35 central and 35 peripheral) were retrospectively selected for this study. The clinical IMRT plans that were initially calculated with the PB algorithm were recalculated with the MC algorithm. Among these paired plans, dosimetric parameters were compared for the targets and critical organs. When compared to MC calculation, PB calculation overestimated doses to the planning target volumes (PTVs) of central and peripheral tumors with different magnitudes. The doses to 95% of the central and peripheral PTVs were overestimated by 9.7% ± 5.6% and 12.0% ± 7.3%, respectively. This dose overestimation did not affect doses to the critical organs, such as the spinal cord and lung. In conclusion, for NSCLC treated with IMRT, dose differences between the PB and MC calculations were different from that of 3D CRT. No significant dose differences in critical organs were observed between the two calculations. PMID:26699560

  10. Lowering Whole-Body Radiation Doses in Pediatric Intensity-Modulated Radiotherapy Through the Use of Unflattened Photon Beams;Flattening filter; Pediatric; Intensity-modulated radiotherapy; Second cancers; Radiation-induced malignancies

    SciTech Connect

    Cashmore, Jason; Ramtohul, Mark; Ford, Dan

    2011-07-15

    Purpose: Intensity modulated radiotherapy (IMRT) has been linked with an increased risk of secondary cancer induction due to the extra leakage radiation associated with delivery of these techniques. Removal of the flattening filter offers a simple way of reducing head leakage, and it may be possible to generate equivalent IMRT plans and to deliver these on a standard linear accelerator operating in unflattened mode. Methods and Materials: An Elekta Precise linear accelerator has been commissioned to operate in both conventional and unflattened modes (energy matched at 6 MV) and a direct comparison made between the treatment planning and delivery of pediatric intracranial treatments using both approaches. These plans have been evaluated and delivered to an anthropomorphic phantom. Results: Plans generated in unflattened mode are clinically identical to those for conventional IMRT but can be delivered with greatly reduced leakage radiation. Measurements in an anthropomorphic phantom at clinically relevant positions including the thyroid, lung, ovaries, and testes show an average reduction in peripheral doses of 23.7%, 29.9%, 64.9%, and 70.0%, respectively, for identical plan delivery compared to conventional IMRT. Conclusions: IMRT delivery in unflattened mode removes an unwanted and unnecessary source of scatter from the treatment head and lowers leakage doses by up to 70%, thereby reducing the risk of radiation-induced second cancers. Removal of the flattening filter is recommended for IMRT treatments.

  11. Elective Lymph Node Irradiation With Intensity-Modulated Radiotherapy: Is Conventional Dose Fractionation Necessary?

    SciTech Connect

    Bedi, Meena; Firat, Selim; Semenenko, Vladimir A.; Schultz, Christopher; Tripp, Patrick; Byhardt, Roger; Wang, Dian

    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

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

    SciTech Connect

    Forsythe, Kevin; Blacksburg, Seth; Stone, Nelson; Stock, Richard G.

    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

  13. Whole brain radiotherapy plus simultaneous in-field boost with image guided intensity-modulated radiotherapy for brain metastases of non-small cell lung cancer

    PubMed Central

    2014-01-01

    Background Whole brain radiotherapy (WBRT) plus sequential focal radiation boost is a commonly used therapeutic strategy for patients with brain metastases. However, recent reports on WBRT plus simultaneous in-field boost (SIB) also showed promising outcomes. The objective of present study is to retrospectively evaluate the efficacy and toxicities of WBRT plus SIB with image guided intensity-modulated radiotherapy (IG-IMRT) for inoperable brain metastases of NSCLC. Methods Twenty-nine NSCLC patients with 87 inoperable brain metastases were included in this retrospective study. All patients received WBRT at a dose of 40 Gy/20 f, and SIB boost with IG-IMRT at a dose of 20 Gy/5 f concurrent with WBRT in the fourth week. Prior to each fraction of IG-IMRT boost, on-line positioning verification and correction were used to ensure that the set-up errors were within 2 mm by cone beam computed tomography in all patients. Results The one-year intracranial control rate, local brain failure rate, and distant brain failure rate were 62.9%, 13.8%, and 19.2%, respectively. The two-year intracranial control rate, local brain failure rate, and distant brain failure rate were 42.5%, 30.9%, and 36.4%, respectively. Both median intracranial progression-free survival and median survival were 10 months. Six-month, one-year, and two-year survival rates were 65.5%, 41.4%, and 13.8%, corresponding to 62.1%, 41.4%, and 10.3% of intracranial progression-free survival rates. Patients with Score Index for Radiosurgery in Brain Metastases (SIR) >5, number of intracranial lesions <3, and history of EGFR-TKI treatment had better survival. Three lesions (3.45%) demonstrated radiation necrosis after radiotherapy. Grades 2 and 3 cognitive impairment with grade 2 radiation leukoencephalopathy were observed in 4 (13.8%) and 4 (13.8%) patients. No dosimetric parameters were found to be associated with these late toxicities. Patients received EGFR-TKI treatment had higher incidence of grades 2–3

  14. Comparison of the dosimetries of 3-dimensions Radiotherapy (3D-RT) with linear accelerator and intensity modulated radiotherapy (IMRT) with helical tomotherapy in children irradiated for neuroblastoma

    PubMed Central

    2012-01-01

    Background Intensity modulated radiotherapy is an efficient radiotherapy technique to increase dose in target volumes and decrease irradiation dose in organs at risk. This last objective is mainly relevant in children. However, previous results suggested that IMRT could increase low dose, factor of risk for secondary radiation induced cancer. This study was performed to compare dose distributions with 3D-radiotherapy (3D-RT) and IMRT with tomotherapy (HT) in children with neuroblastoma. Seven children with neuroblastoma were irradiated. Treatment plans were calculated for 3D-RT, and for HT. For the volume of interest, the PTV-V95% and conformity index were calculated. Dose constraints of all the organs at risk and integral dose were compared. Results The conformity index was statistically better for HT than for 3D-RT. PTV-V95% constraint was reached in 6 cases with HT compared to 2 cases with 3D-RT. For the ipsilateral kidney of the tumor, the V12 Gy constraint was reached for 3 patients with both methods. The values were lower with HT than with 3D-RT in two cases and higher in one case. The threshold was not reached for one patient with either technique, but the value was lower with HT than with 3D-RT. For the contralateral kidney of the tumors, the V12 Gy constraint was reached for all patients with both methods. The values were lower with HT than with 3D-RT in 5 of 7 children, equal in one patient and higher in one patient. The organ-at-risk volumes receiving low doses were significantly lower with 3D-RT but larger for the highest doses, compared to those irradiated with HT. The integral doses were not different. Conclusions IMRT with HT allows a better conformity treatment, a more frequently acceptable PTV-V95% than 3D-RT and, concomitantly, a better shielding of the kidneys. The integral doses are comparable between both techniques but consideration of differences in dose distribution between the two techniques, for the organs at risk, has to be taken in

  15. Risk Factors for Hearing Loss in Patients Treated With Intensity-Modulated Radiotherapy for Head-and-Neck Tumors

    SciTech Connect

    Zuur, Charlotte L.; Dreschler, Wouter A.; Balm, Alfons J.; Rasch, Coen R.

    2009-06-01

    Purpose: Radiotherapy (RT) is a common treatment of head-and-neck carcinoma. The objective of this study was to perform a prospective multivariate assessment of the dose-effect relationship between intensity-modulated RT and hearing loss. Methods and Materials: Pure tone audiometry at 0.250-16 kHz was obtained before and after treatment in 101 patients (202 ears). All patients received full-course intensity-modulated RT (range, 56-70 Gy), with a median cochlear dose of 11.4 Gy (range, 0.2-69.7). Results: Audiometry was performed 1 week before and a median of 9 weeks (range, 1-112) after treatment. The mean hearing deterioration at pure tone average air-conduction 1-2-4 kHz was small (from 28.6 dB HL to 30.1 dB HL). However, individual patients showed clinically significant hearing loss, with 10-dB threshold shift incidences of 13% and 18% at pure tone averages air-conduction 1-2-4 kHz and 8-10-12.5 kHz, respectively. Post-treatment hearing capability was unfavorable in the case of greater inner ear radiation doses (p <0.0001), unfavorable baseline hearing capability (p <0.0001), green-eyed patients (p <0.0001), and older age (p <0.0001). Using multivariate analysis, a prediction of individual hearing capabiltity after treatment was made. Conclusion: RT-induced hearing loss in the mean population is modest. However, clinically significant hearing loss was observed in older patients with green eyes and unfavorable pretreatment hearing. In these patients, the intended radiation dose may be adjusted according to the proposed predictive model, aiming to decrease the risk of ototoxicity.

  16. The Failure Patterns of Oral Cavity Squamous Cell Carcinoma After Intensity-Modulated Radiotherapy-University of Iowa Experience

    SciTech Connect

    Yao Min . E-mail: min-yao@uiowa.edu; Chang, Kristi; Funk, Gerry F.; Lu Heming; Tan Huaming; Wacha, Judith C; Dornfeld, Kenneth J.; Buatti, John M.

    2007-04-01

    Purpose: Determine the failure patterns of oral cavity squamous cell carcinoma (SCC) treated with intensity-modulated radiotherapy (IMRT). Methods and Materials: Between May 2001 and July 2005, 55 patients with oral cavity SCC were treated with IMRT for curative intent. Forty-nine received postoperative IMRT, 5 definitive IMRT, and 1 neoadjuvant. Three target volumes were defined (clinical target CTV1, CTV2, and CTV3). The failure patterns were determined by coregistration or comparison of the treatment planning computed tomography to the images obtained at the time of recurrence. Results: The median follow-up for all patients was 17.1 months (range, 0.27-59.3 months). The median follow-up for living patients was 23.9 months (range, 9.3-59.3 months). Nine patients had locoregional failures: 4 local failures only, 2 regional failures only, and 3 had both local and regional failures. Five patients failed distantly; of these, 3 also had locoregional failures. The 2-year overall survival, disease-specific survival, local recurrence-free survival, locoregional recurrence-free survival, and distant disease-free survival was 68%, 74%, 85%, 82%, and 89%, respectively. The median time from treatment completion to locoregional recurrence was 4.1 months (range, 3.0-12.1 months). Except for 1 patient who failed in contralateral lower neck outside the radiation field, all failed in areas that had received a high dose of radiation. The locoregional control is strongly correlated with extracapsular extension. Conclusions: Intensity-modulated RT is effective for oral cavity SCC. Most failures are in-field failures. Further clinical studies are necessary to improve the outcomes of patients with high-risk features, particularly for those with extracapsular extension.

  17. Dosimetric Advantage of Intensity-Modulated Radiotherapy for Whole Ventricles in the Treatment of Localized Intracranial Germinoma

    SciTech Connect

    Sakanaka, Katsuyuki; Mizowaki, Takashi; Hiraoka, Masahiro

    2012-02-01

    Purpose: To investigate the dosimetric advantage of intensity-modulated radiotherapy (IMRT) for whole ventricles (WV) in patients with a localized intracranial germinoma receiving induction chemotherapy. Methods and Materials: Data from 12 consecutive patients with localized intracranial germinomas who received induction chemotherapy and radiotherapy were used. Four-field coplanar three-dimensional conformal radiotherapy (3D-CRT) and seven-field coplanar IMRT plans were created. In both plans, 24 Gy was prescribed in 12 fractions for the planning target volume (PTV) involving WV and tumor bed. In IMRT planning, optimization was conducted to reduce the doses to the organs at risk (OARs) as much as possible, keeping the minimum dose equivalent to that of 3D-CRT. The 3D-CRT and IMRT plans were compared in terms of the dose-volume statistics for target coverage and the OARs. Results: IMRT significantly increased the percentage volume of the PTV receiving 24 Gy compared with 3D-CRT (93.5% vs. 84.8%; p = 0.007), while keeping target homogeneity equivalent to 3D-CRT (p = 0.869). The absolute percentage reduction in the irradiated volume of the normal brain receiving 100%, 75%, 50%, and 25% of 24 Gy ranged from 0.7% to 16.0% in IMRT compared with 3D-CRT (p < 0.001). No significant difference was observed in the volume of the normal brain receiving 10% and 5% of 24 Gy between IMRT and 3D-CRT. Conformation number was significantly improved in IMRT (p < 0.001). For other OARs, the mean dose to the cochlea was reduced significantly in IMRT by 22.3% of 24 Gy compared with 3D-CRT (p < 0.001). Conclusions: Compared with 3D-CRT, IMRT for WV improved the target coverage and reduced the irradiated volume of the normal brain in patients with intracranial germinomas receiving induction chemotherapy. IMRT for WV with induction chemotherapy could reduce the late side effects from cranial irradiation without compromising control of the tumor.

  18. Optimization and quality assurance of an image-guided radiation therapy system for intensity-modulated radiation therapy radiotherapy

    SciTech Connect

    Tsai, Jen-San; Micaily, Bizhan; Miyamoto, Curtis

    2012-10-01

    To develop a quality assurance (QA) of XVI cone beam system (XVIcbs) for its optimal imaging-guided radiotherapy (IGRT) implementation, and to construe prostate tumor margin required for intensity-modulated radiation therapy (IMRT) if IGRT is unavailable. XVIcbs spatial accuracy was explored with a humanoid phantom; isodose conformity to lesion target with a rice phantom housing a soap as target; image resolution with a diagnostic phantom; and exposure validation with a Radcal ion chamber. To optimize XVIcbs, rotation flexmap on coincidency between gantry rotational axis and that of XVI cone beam scan was investigated. Theoretic correlation to image quality of XVIcbs rotational axis stability was elaborately studied. Comprehensive QA of IGRT using XVIcbs has initially been explored and then implemented on our general IMRT treatments, and on special IMRT radiotherapies such as head and neck (H and N), stereotactic radiation therapy (SRT), stereotactic radiosurgery (SRS), and stereotactic body radiotherapy (SBRT). Fifteen examples of prostate setup accounted for 350 IGRT cone beam system were analyzed. IGRT accuracy results were in agreement {+-} 1 mm. Flexmap 0.25 mm met the manufacturer's specification. Films confirmed isodose coincidence with target (soap) via XVIcbs, otherwise not. Superficial doses were measured from 7.2-2.5 cGy for anatomic diameters 15-33 cm, respectively. Image quality was susceptible to rotational stability or patient movement. IGRT using XVIcbs on general IMRT treatments such as prostate, SRT, SRS, and SBRT for setup accuracy were verified; and subsequently coordinate shifts corrections were recorded. The 350 prostate IGRT coordinate shifts modeled to Gaussian distributions show central peaks deviated off the isocenter by 0.6 {+-} 3.0 mm, 0.5 {+-} 4.5 mm in the X(RL)- and Z(SI)-coordinates, respectively; and 2.0 {+-} 3.0 mm in the Y(AP)-coordinate as a result of belly and bladder capacity variations. Sixty-eight percent of confidence was

  19. Image-guided volumetric modulated arc therapy for breast cancer: a feasibility study and plan comparison with three-dimensional conformal and intensity-modulated radiotherapy

    PubMed Central

    Kaul, D; Nadobny, J; Wille, B; Sehouli, J; Budach, V

    2013-01-01

    Objective: To test the feasibility of volumetric modulated arc therapy (VMAT) in breast cancer and to compare it with three-dimensional conformal radiotherapy (3D-CRT) as conventional tangential field radiotheraphy (conTFRT). Methods: 12 patients (Stage I, 8: 6 left breast cancer and 2 right breast cancer; Stage II, 4: 2 on each side). Three plans were calculated for each case after breast-conserving surgery. Breast was treated with 50 Gy in four patients with supraclavicular lymph node inclusion, and in eight patients without the node inclusion. Multiple indices and dose parameters were measured. Results: V95% was not achieved by any modality. Heterogeneity index: 0.16 (VMAT), 0.13 [intensity-modulated radiotherapy (IMRT)] and 0.14 (conTFRT). Conformity index: 1.06 (VMAT), 1.15 (IMRT) and 1.69 (conTFRT). For both indices, IMRT was more effective than VMAT (p=0.009, p=0.002). Dmean and V20 for ipsilateral lung were lower for IMRT than VMAT (p=0.0001, p=0.003). Dmean, V2 and V5 of contralateral lung were lower for IMRT than VMAT (p>0.0001, p=0.005). Mean dose and V5 to the heart were lower for IMRT than for VMAT (p=0.015, p=0.002). Conclusion: The hypothesis of equivalence of VMAT to IMRT was not confirmed for planning target volume parameter or dose distribution to organs at risk. VMAT was inferior to IMRT and 3D-CRT with regard to dose distribution to organs at risk, especially at the low dose level. Advances in knowledge: New technology VMAT is not superior to IMRT or conventional radiotherapy in breast cancer in any aspect. PMID:24167182

  20. Dosimetric effect of Elekta Beam Modulator micromultileaf in three-dimensional conformal radiotherapy and intensity-modulated radiotherapy for prostate cancer

    SciTech Connect

    Carosi, Alessandra Ingrosso, Gianluca; Ponti, Elisabetta; Tolu, Barbara; Murgia, Alessandra; Cristino, Daniela di; Santoni, Riccardo

    2014-07-01

    The purpose of this study is to analyze the dosimetric effect of Elekta Beam Modulator in 3-dimensional conformal radiation therapy (3DCRT) and in intensity-modulated radiation therapy (IMRT) for localized prostate cancer. We compared treatment plans developed with 2 different Elekta multileaf collimators (MLC): Beam Modulator micro-MLC (mMLC) (4-mm leaf width at the isocenter) and standard MLC (10-mm leaf width at the isocenter). The comparison was performed for 15 patients with localized prostate cancer in 3DCRT and IMRT delivery; a total of 60 treatment plans were processed. The dose-volume histograms were used to provide the quantitative comparison between plans. In particular, we analyzed differences between rectum and bladder sparing in terms of a set of appropriate Vx (percentage of organ at risk [OAR] volume receiving the x dose) and differences between target conformity and coverage in terms of coverage factor and conformation number. Our analysis demonstrates that in 3DCRT there is an advantage in the use of Elekta Beam Modulator mMLC in terms of organ sparing; in particular, a significant decrease in rectal V{sub 60} and V{sub 50} (p = 0.001) and in bladder V{sub 70} and V{sub 65} (p = 0.007 and 0.002, respectively) was found. Moreover, a better target dose conformity was obtained (p = 0.002). IMRT plans comparison demonstrated no significant differences between the use of the 4 or 10-mm MLCs. Our analysis shows that in 3DCRT the use of the Elekta Beam Modulator mMLC gives a gain in target conformity and in OARs dose sparing whereas in IMRT plans there is no advantage.

  1. Long-Term Outcome After Static Intensity-Modulated Total Body Radiotherapy Using Compensators Stratified by Pediatric and Adult Cohorts

    SciTech Connect

    Schneider, Ralf A. Schultze, Juergen; Jensen, J. Martin; Hebbinghaus, Dieter; Galalae, Razvan M.

    2008-01-01

    Purpose: To report the long-term outcome after total body irradiation with intensity-modulating compensators and allogeneic/autologous transplantation, especially in terms of therapy-related toxicity in pediatric and adult cohorts. Methods and Materials: A total of 257 consecutive patients (40 children and 217 adults) have been treated since 1983 with TBI using static intensity-modulated radiotherapy for hematologic malignancies. The total dose of 12 Gy was applied in six fractions within 3 days before allogeneic (n = 174) or autologous (n = 83) transplantation. The median follow-up was 9.2 years. Results: The 5-year overall survival rate was 47.9% (49.8% for the adults and 37.5% for the children, p = 0.171). The 5-year tumor-related mortality rate was 23%, and the 5-year treatment-related mortality rate 29.2% (29.5% in the adults and 27.5% in the pediatric patients). Interstitial pneumonitis developed in 28 (10.9%) of 257 patients and in 12.5% of the pediatric cohort. The interstitial pneumonitis rate was 25% in pediatric patients treated with a 12-Gy lung dose compared with 4.2% for those treated to an 11-Gy lung dose. The overall survival rate stratified by lung dose was 26.7% for 12 Gy and 52.4% for 11 Gy (p = 0.001). The incidence of veno-occlusive disease and cataract was 5.8% and 6.6% in all patients and 12.5% and 15% in the pediatric patients, respectively (p < 0.05). Secondary malignancies were found in 4.3% of all patients, all in the adult cohort at transplantation. Conclusion: Static intensity-modulated total body irradiation with a total dose of 12 Gy before allogeneic/autologous transplantation is a successful treatment with good long-term outcome and acceptable therapy-related toxicities. Constraining the lung dose to 11 Gy substantially lowered the actuarial treatment-related mortality. This effect was especially striking in the pediatric patients.

  2. Dosimetric evaluation of a simple planning method for improving intensity-modulated radiotherapy for stage III lung cancer

    PubMed Central

    Lu, Jia-Yang; Lin, Zhu; Zheng, Jing; Lin, Pei-Xian; Cheung, Michael Lok-Man; Huang, Bao-Tian

    2016-01-01

    This study aimed to evaluate the dosimetric outcomes of a base-dose-plan-compensation (BDPC) planning method for improving intensity-modulated radiotherapy (IMRT) for stage III lung cancer. For each of the thirteen included patients, three types of planning methods were applied to obtain clinically acceptable plans: (1) the conventional optimization method (CO); (2) a split-target optimization method (STO), in which the optimization objectives were set higher dose for the target with lung density; (3) the BDPC method, which compensated for the optimization-convergence error by further optimization based on the CO plan. The CO, STO and BDPC methods were then compared regarding conformity index (CI), homogeneity index (HI) of the target, organs at risk (OARs) sparing and monitor units (MUs). The BDPC method provided better HI/CI by 54%/7% on average compared to the CO method and by 38%/3% compared to the STO method. The BDPC method also spared most of the OARs by up to 9%. The average MUs of the CO, STO and BDPC plans were 890, 937 and 1023, respectively. Our results indicated that the BDPC method can effectively improve the dose distribution in IMRT for stage III lung cancer, at the expense of more MUs. PMID:27009235

  3. Feasibility of intensity-modulated radiotherapy combined with gemcitabine and S-1 for patients with pancreatic cancer

    PubMed Central

    KENNOKI, NORIFUMI; NAKAYAMA, HIDETSUGU; NAGAKAWA, YUICHI; HOSOKAWA, YUICHI; ITONAGA, TOMOHIRO; TAJIMA, YU; SHIRAISHI, SACHICA; MIKAMI, RYUJI; TSUCHIDA, AKIHIKO; TOKUUYE, KOICHI

    2016-01-01

    The aim of the present study was to establish whether intensity-modulated radiotherapy (IMRT) with concurrent gemcitabine and S-1 is a feasible treatment option for patients with locally advanced pancreatic ductal adenocarcinoma. Patients with pancreatic ductal adenocarcinoma were prospectively enrolled. An IMRT dose of 50.4 Gy in 28 fractions with concurrent gemcitabine at a dose of 600 mg/m2 and S-1 at a dose of 60 mg were administrated. Adverse events and associated dosimetric factors were assessed. Between February 2012 and January 2014, 17 patients with borderline resectable and 4 with unresectable pancreatic cancer were enrolled. None of the patients experienced grade 3 or worse nausea and vomiting. The planning target volume (≥200 vs. <200 ml) was a statistically significant predictive factor for neutrocytopenia (≥500 vs. 500/µl, P=0.02). Concurrent IMRT with gemcitabine and S-1 for patients with locally advanced pancreatic cancer is feasible, with tolerable hematological toxicities and low gastrointestinal toxicities. PMID:26870355

  4. Prognostic value of parotid lymph node metastasis in patients with nasopharyngeal carcinoma receiving intensity-modulated radiotherapy.

    PubMed

    Zhang, Yuan; Li, Wen-Fei; Chen, Lei; Mao, Yan-Ping; Guo, Rui; Zhang, Fan; Peng, Hao; Liu, Li-Zhi; Li, Li; Liu, Qing; Ma, Jun

    2015-09-08

    The prognostic value and staging category of parotid lymph node (PLN) metastasis in nasopharyngeal carcinoma (NPC) remain unknown. We retrospectively reviewed MRI scans and medical records for 1811 NPC patients who received intensity-modulated radiotherapy. The diagnosis of PLN metastasis was mainly based on MRI follow-up. Twenty-five positive PLNs in 21/1811 patients were identified; the incidence of PLN metastasis was 1.2%. PLN metastasis was significantly associated with advanced N-category and stage. Ten of the 21 patients received irradiation of the involved PLNs; the PLN recurrence rate was significantly higher for patients who received no irradiation; thus only patients with irradiated PLN were included in prognostic analyses. PLN metastasis was associated with significantly poorer progression-free survival, overall survival and distant metastasis-free survival (DMFS), but not regional or local relapse-free survival, in univariate analysis. In multivariate analysis, PLN metastasis was also significantly associated with poor DMFS. PLN involvement had a significantly higher hazard ratio (HR) for distant failure than N2 disease and similar HR to N3 disease. In conclusion, PLN metastasis is rare in NPC and was associated with similarly poor DMFS as N3 disease. PLN metastasis should be suspected in advanced nodal disease, but diagnosed with care before administering aggressive treatment.

  5. Prognostic value of parotid lymph node metastasis in patients with nasopharyngeal carcinoma receiving intensity-modulated radiotherapy.

    PubMed

    Zhang, Yuan; Li, Wen-Fei; Chen, Lei; Mao, Yan-Ping; Guo, Rui; Zhang, Fan; Peng, Hao; Liu, Li-Zhi; Li, Li; Liu, Qing; Ma, Jun

    2015-01-01

    The prognostic value and staging category of parotid lymph node (PLN) metastasis in nasopharyngeal carcinoma (NPC) remain unknown. We retrospectively reviewed MRI scans and medical records for 1811 NPC patients who received intensity-modulated radiotherapy. The diagnosis of PLN metastasis was mainly based on MRI follow-up. Twenty-five positive PLNs in 21/1811 patients were identified; the incidence of PLN metastasis was 1.2%. PLN metastasis was significantly associated with advanced N-category and stage. Ten of the 21 patients received irradiation of the involved PLNs; the PLN recurrence rate was significantly higher for patients who received no irradiation; thus only patients with irradiated PLN were included in prognostic analyses. PLN metastasis was associated with significantly poorer progression-free survival, overall survival and distant metastasis-free survival (DMFS), but not regional or local relapse-free survival, in univariate analysis. In multivariate analysis, PLN metastasis was also significantly associated with poor DMFS. PLN involvement had a significantly higher hazard ratio (HR) for distant failure than N2 disease and similar HR to N3 disease. In conclusion, PLN metastasis is rare in NPC and was associated with similarly poor DMFS as N3 disease. PLN metastasis should be suspected in advanced nodal disease, but diagnosed with care before administering aggressive treatment. PMID:26345410

  6. Dose distribution analysis of physical and dynamic wedges by using an intensity-modulated radiotherapy MatriXX

    NASA Astrophysics Data System (ADS)

    Lee, Hae-Kag; Cho, Jae-Hwan; Cho, Dae-chul

    2013-05-01

    This study investigated differences between the physical wedge and the dynamic wedge distributions of radiation by using an intensity-modulated radiotherapy (ImRT) MatriXX. The linear accelerator used X-rays with energy levels of 6 MV and 10 MV to adjust the collimator by motoring the independent jaws (X1, X2, Y1, Y2) for setting wedge angles of 15, 30, 45, and 60 degrees. The collimator field size was set as 10 × 10 cm2 or 20 × 20 cm2 at the maximum dose point. The dose distribution for each wedge had ±5% and ±11% errors for field sizes of 10 × 10 cm2 and 20 × 20 cm2, respectively. The error was greatest at a wedge angle of 45 degrees and was pronounced at the end of the dynamic wedge where Y1 and Y2 met. Consequently, concluded that the dose distributions were similar for both wedges for the field size of a small beam profile. The beam dose was greatly increased at the end of the dynamic wedge. A more precise estimate of the therapeutic dose of radiation for a dynamic wedge that nearly matches that of the physical wedge can be achieved by correcting of the increasing part of the beam dose. The findings imply that a heavy wedge filter should not be used when calculating the isodose distribution and the therapeutic dose.

  7. Prognostic Value of Subclassification Using MRI in the T4 Classification Nasopharyngeal Carcinoma Intensity-Modulated Radiotherapy Treatment

    SciTech Connect

    Chen Lei; Liu Lizhi; Chen Mo; Li Wenfei; Yin Wenjing; Lin Aihua; Sun Ying; Li Li; Ma Jun

    2012-09-01

    Purpose: To subclassify patients with the T4 classification nasopharyngeal carcinoma (NPC), according to the seventh edition of the American Joint Committee on Cancer staging system, using magnetic resonance imaging (MRI), and to evaluate the prognostic value of subclassification after intensity-modulated radiotherapy (IMRT). Methods and Materials: A total of 140 patients who underwent MRI and were subsequently histologically diagnosed with nondisseminated classification T4 NPC received IMRT as their primary treatment and were included in this retrospective study. T4 patients were subclassified into two grades: T4a was defined as a primary nasopharyngeal tumor with involvement of the masticator space only; and T4b was defined as involvement of the intracranial region, cranial nerves, and/or orbit. Results: The 5-year overall survival (OS) rate and distant metastasis-free survival (DMFS) rate for T4a patients (82.5% and 87.0%, respectively), were significantly higher than for T4b patients (62.6% and 66.8%; p = 0.033 and p = 0.036, respectively). The T4a/b subclassification was an independent prognostic factor for OS (hazard ratio = 2.331, p = 0.032) and DMFS (hazard ratio = 2.602, p = 0.034), and had no significant effect on local relapse-free survival. Conclusions: Subclassification of T4 patients, as T4a or T4b, using MRI according to the site of invasion, has prognostic value for the outcomes of IMRT treatment in NPC.

  8. Dosimetric evaluation of a simple planning method for improving intensity-modulated radiotherapy for stage III lung cancer.

    PubMed

    Lu, Jia-Yang; Lin, Zhu; Zheng, Jing; Lin, Pei-Xian; Cheung, Michael Lok-Man; Huang, Bao-Tian

    2016-01-01

    This study aimed to evaluate the dosimetric outcomes of a base-dose-plan-compensation (BDPC) planning method for improving intensity-modulated radiotherapy (IMRT) for stage III lung cancer. For each of the thirteen included patients, three types of planning methods were applied to obtain clinically acceptable plans: (1) the conventional optimization method (CO); (2) a split-target optimization method (STO), in which the optimization objectives were set higher dose for the target with lung density; (3) the BDPC method, which compensated for the optimization-convergence error by further optimization based on the CO plan. The CO, STO and BDPC methods were then compared regarding conformity index (CI), homogeneity index (HI) of the target, organs at risk (OARs) sparing and monitor units (MUs). The BDPC method provided better HI/CI by 54%/7% on average compared to the CO method and by 38%/3% compared to the STO method. The BDPC method also spared most of the OARs by up to 9%. The average MUs of the CO, STO and BDPC plans were 890, 937 and 1023, respectively. Our results indicated that the BDPC method can effectively improve the dose distribution in IMRT for stage III lung cancer, at the expense of more MUs. PMID:27009235

  9. Intensity modulated proton therapy.

    PubMed

    Kooy, H M; Grassberger, C

    2015-07-01

    Intensity modulated proton therapy (IMPT) implies the electromagnetic spatial control of well-circumscribed "pencil beams" of protons of variable energy and intensity. Proton pencil beams take advantage of the charged-particle Bragg peak-the characteristic peak of dose at the end of range-combined with the modulation of pencil beam variables to create target-local modulations in dose that achieves the dose objectives. IMPT improves on X-ray intensity modulated beams (intensity modulated radiotherapy or volumetric modulated arc therapy) with dose modulation along the beam axis as well as lateral, in-field, dose modulation. The clinical practice of IMPT further improves the healthy tissue vs target dose differential in comparison with X-rays and thus allows increased target dose with dose reduction elsewhere. In addition, heavy-charged-particle beams allow for the modulation of biological effects, which is of active interest in combination with dose "painting" within a target. The clinical utilization of IMPT is actively pursued but technical, physical and clinical questions remain. Technical questions pertain to control processes for manipulating pencil beams from the creation of the proton beam to delivery within the patient within the accuracy requirement. Physical questions pertain to the interplay between the proton penetration and variations between planned and actual patient anatomical representation and the intrinsic uncertainty in tissue stopping powers (the measure of energy loss per unit distance). Clinical questions remain concerning the impact and management of the technical and physical questions within the context of the daily treatment delivery, the clinical benefit of IMPT and the biological response differential compared with X-rays against which clinical benefit will be judged. It is expected that IMPT will replace other modes of proton field delivery. Proton radiotherapy, since its first practice 50 years ago, always required the highest level of

  10. Intensity modulated proton therapy

    PubMed Central

    Grassberger, C

    2015-01-01

    Intensity modulated proton therapy (IMPT) implies the electromagnetic spatial control of well-circumscribed “pencil beams” of protons of variable energy and intensity. Proton pencil beams take advantage of the charged-particle Bragg peak—the characteristic peak of dose at the end of range—combined with the modulation of pencil beam variables to create target-local modulations in dose that achieves the dose objectives. IMPT improves on X-ray intensity modulated beams (intensity modulated radiotherapy or volumetric modulated arc therapy) with dose modulation along the beam axis as well as lateral, in-field, dose modulation. The clinical practice of IMPT further improves the healthy tissue vs target dose differential in comparison with X-rays and thus allows increased target dose with dose reduction elsewhere. In addition, heavy-charged-particle beams allow for the modulation of biological effects, which is of active interest in combination with dose “painting” within a target. The clinical utilization of IMPT is actively pursued but technical, physical and clinical questions remain. Technical questions pertain to control processes for manipulating pencil beams from the creation of the proton beam to delivery within the patient within the accuracy requirement. Physical questions pertain to the interplay between the proton penetration and variations between planned and actual patient anatomical representation and the intrinsic uncertainty in tissue stopping powers (the measure of energy loss per unit distance). Clinical questions remain concerning the impact and management of the technical and physical questions within the context of the daily treatment delivery, the clinical benefit of IMPT and the biological response differential compared with X-rays against which clinical benefit will be judged. It is expected that IMPT will replace other modes of proton field delivery. Proton radiotherapy, since its first practice 50 years ago, always required the

  11. 3D-Conformal Versus Intensity-Modulated Postoperative Radiotherapy of Vaginal Vault: A Dosimetric Comparison

    SciTech Connect

    Cilla, Savino; Macchia, Gabriella Digesu, Cinzia; Deodato, Francesco; Romanella, Michele; Ferrandina, Gabriella; Padula, Gilbert; Picardi, Vincenzo; Scambia, Giovanni; Morganti, Alessio Giuseppe

    2010-07-01

    We evaluated a step-and-shoot IMRT plan in the postoperative irradiation of the vaginal vault compared with equispaced beam arrangements (3-5) 3D-radiotherapy (RT) optimized plans. Twelve patients were included in this analysis. Four plans for each patient were compared in terms of dose-volume histograms, homogeneity index (HI), and conformity index (CI): (1) 3 equispaced beam arrangement 3D-RT; (2) 4 equispaced beam arrangement 3D-RT; (3) 5 equispaced beam arrangement 3D-RT; (4) step-and-shoot IMRT technique. CI showed a good discrimination between the four plans. The mean scores of CI were 0.58 (range: 0.38-0.67) for the 3F-CRT plan, 0.58 (range: 0.41-0.66) for 4F-CRT, 0.62 (range: 0.43-0.68) for 5F-CRT and 0.69 (range: 0.58-0.78) for the IMRT plan. A significant improvement of the conformity was reached by the IMRT plan (p < 0.001 for all comparisons). As expected, the increment of 3D-CRT fields was associated with an improvement of target dose conformity and homogeneity; on the contrary, in the IMRT plans, a better conformity was associated to a worse target dose homogeneity. A significant reduction in terms of D{sub mean}, V90%, V95%, V100% was recorded for rectal and bladder irradiation with the IMRT plan. Surprisingly, IMRT supplied a significant dose reduction also for rectum and bladder V30% and V50%. A significant dosimetric advantage of IMRT over 3D-RT in the adjuvant treatment of vaginal vault alone in terms of treatment conformity and rectum and bladder sparing is shown.

  12. Single-arc volumetric-modulated arc therapy (sVMAT) as adjuvant treatment for gastric cancer: Dosimetric comparisons with three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT)

    SciTech Connect

    Wang, Xin; Li, Guangjun; Zhang, Yingjie; Bai, Sen; Xu, Feng; Wei, Yuquan; Gong, Youling

    2013-01-01

    To compare the dosimetric differences between the single-arc volumetric-modulated arc therapy (sVMAT), 3-dimensional conformal radiotherapy (3D-CRT), and intensity-modulated radiotherapy (IMRT) techniques in treatment planning for gastric cancer as adjuvant radiotherapy. Twelve patients were retrospectively analyzed. In each patient's case, the parameters were compared based on the dose-volume histogram (DVH) of the sVMAT, 3D-CRT, and IMRT plans, respectively. Three techniques showed similar target dose coverage. The maximum and mean doses of the target were significantly higher in the sVMAT plans than that in 3D-CRT plans and in the 3D-CRT/IMRT plans, respectively, but these differences were clinically acceptable. The IMRT and sVMAT plans successfully achieved better target dose conformity, reduced the V{sub 20/30}, and mean dose of the left kidney, as well as the V{sub 20/30} of the liver, compared with the 3D-CRT plans. And the sVMAT technique reduced the V{sub 20} of the liver much significantly. Although the maximum dose of the spinal cord were much higher in the IMRT and sVMAT plans, respectively (mean 36.4 vs 39.5 and 40.6 Gy), these data were still under the constraints. Not much difference was found in the analysis of the parameters of the right kidney, intestine, and heart. The IMRT and sVMAT plans achieved similar dose distribution to the target, but superior to the 3D-CRT plans, in adjuvant radiotherapy for gastric cancer. The sVMAT technique improved the dose sparings of the left kidney and liver, compared with the 3D-CRT technique, but showed few dosimetric advantages over the IMRT technique. Studies are warranted to evaluate the clinical benefits of the VMAT treatment for patients with gastric cancer after surgery in the future.

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

    SciTech Connect

    Lin, Steven H.; Wang Lu; Myles, Bevan; Thall, Peter F.; Hofstetter, Wayne L.; Swisher, Stephen G.; Ajani, Jaffer A.; Cox, James D.; Komaki, Ritsuko; Liao Zhongxing

    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

  14. Prospective Trial of High-Dose Reirradiation Using Daily Image Guidance With Intensity-Modulated Radiotherapy for Recurrent and Second Primary Head-and-Neck Cancer

    SciTech Connect

    Chen, Allen M.; Farwell, D. Gregory; Luu, Quang; Cheng, Suzan; Donald, Paul J.; Purdy, James A.

    2011-07-01

    Purpose: To report a single-institutional experience using intensity-modulated radiotherapy with daily image-guided radiotherapy for the reirradiation of recurrent and second cancers of the head and neck. Methods and Materials: Twenty-one consecutive patients were prospectively treated with intensity-modulated radiotherapy from February 2006 to March 2009 to a median dose of 66 Gy (range, 60-70 Gy). None of these patients received concurrent chemotherapy. Daily helical megavoltage CT scans were obtained before each fraction as part of an image-guided radiotherapy registration protocol for patient alignment. Results: The 1- and 2-year estimates of in-field control were 72% and 65%, respectively. A total of 651 daily megavoltage CT scans were obtained. The mean systematic shift to account for interfraction motion was 1.38 {+-} 1.25 mm, 1.79 {+-} 1.45 mm, and 1.98 {+-} 1.75 mm for the medial-lateral, superior-inferior, and anterior-posterior directions, respectively. Pretreatment shifts of >3 mm occurred in 19% of setups in the medial-lateral, 27% in the superior-inferior, and 33% in the anterior-posterior directions, respectively. There were no treatment-related fatalities or hospitalizations. Complications included skin desquamation, odynophagia, otitis externa, keratitis, naso-lacrimal duct stenosis, and brachial plexopathy. Conclusions: Intensity-modulated radiotherapy with daily image guidance results in effective disease control with relatively low morbidity and should be considered for selected patients with recurrent and second primary cancers of the head and neck.

  15. Efficacy and Safety of Intensity-Modulated Radiotherapy Following Transarterial Chemoembolization in Patients With Unresectable Hepatocellular Carcinoma

    PubMed Central

    Zhang, Tao; Zhao, Yu-Ting; Wang, Zhi; Li, Cheng-Rui; Jin, Jing; Jia, Angela Y.; Wang, Shu-Lian; Song, Yong-Wen; Liu, Yue-Ping; Ren, Hua; Fang, Hui; Bao, Hui; Liu, Xin-Fan; Yu, Zi-Hao; Li, Ye-Xiong; Wang, Wei-Hu

    2016-01-01

    Abstract Three-dimensional conformal radiotherapy in combination with transarterial chemoembolization (TACE) has been beneficial in patients with unresectable hepatocellular carcinoma (HCC). There have been few clinical reports on the use of intensity-modulated radiotherapy (IMRT) in combination with TACE for these patients. The purpose of this study was to assess the efficacy and toxicity of IMRT following TACE in unresectable HCC. The medical records of consecutive patients with unresectable HCC, who underwent IMRT following TACE from January 2009 to June 2014, were retrospectively reviewed in order to assess the overall survival (OS), progression-free survival (PFS), tumor response, and treatment-associated toxicity. A total of 64 lesions in 54 patients were included in the analysis. IMRT was delivered at a median dose of 50 Gy (range 44–70 Gy) at 1.8 to 2.0 Gy per fraction. The overall response rate was achieved in 64.8% of patients with complete response in 20.4% of patients at 3 months after completion of IMRT. The median OS was 20.2 months (95% CI = 8.6–31.9), and the actuarial 1-, 2-, and 3-year OS rates were 84.6%, 49.7%, and 36.7%, respectively. The median PFS was 10.5 months (95% CI = 7.3–13.7) and the 1-, 2-, and 3-year PFS rates were 44.2%, 23.4%, and 14.6%, respectively. The responders had a significantly higher OS rate than the nonresponders (3-year OS 48.0% vs 14.4%, P = 0.001). During and the first month following IMRT, 10 (18.5%) patients developed grade 3 hematological toxicity, and 3 (5.6%) developed grade 3 hepatic toxicity. No patient experienced grade 4 or 5 toxicity. Radiation-induced liver disease was not observed. Our findings suggest that IMRT following TACE could be a favorable treatment option for both its safety profile and clinical benefit in patients with unresectable HCC. PMID:27227954

  16. Reducing the risk of xerostomia and mandibular osteoradionecrosis: the potential benefits of intensity modulated radiotherapy in advanced oral cavity carcinoma.

    PubMed

    Ahmed, Merina; Hansen, Vibeke N; Harrington, Kevin J; Nutting, Christopher M

    2009-01-01

    Radiation therapy for squamous cell carcinoma of the oral cavity may be curative, but carries a risk of permanent damage to bone, salivary glands, and other soft tissues. We studied the potential of intensity modulated radiotherapy (IMRT) to improve target volume coverage, and normal tissue sparing for advanced oral cavity carcinoma (OCC). Six patients with advanced OCC requiring bilateral irradiation to the oral cavity and neck were studied. Standard 3D conformal radiotherapy (3DCRT) and inverse-planned IMRT dose distributions were compared by using dose-volume histograms. Doses to organs at risk, including spinal cord, parotid glands, and mandible, were assessed as surrogates of radiation toxicity. PTV1 mean dose was 60.8 +/- 0.8 Gy for 3DCRT and 59.8 +/- 0.1 Gy for IMRT (p = 0.04). PTV1 dose range was 24.7 +/- 6 Gy for 3DCRT and 15.3 +/- 4 Gy for IMRT (p = 0.001). PTV2 mean dose was 54.5 +/- 0.8 Gy for 3DCRT and for IMRT was 54.2 +/- 0.2 Gy (p = 0.34). PTV2 dose range was improved by IMRT (7.8 +/- 3.2 Gy vs. 30.7 +/- 12.8 Gy, p = 0.006). Homogeneity index (HI) values for PTV2 were closer to unity using IMRT (p = 0.0003). Mean parotid doses were 25.6 +/- 2.7 Gy for IMRT and 42.0 +/- 8.8 Gy with 3DCRT (p = 0.002). The parotid V30 in all IMRT plans was <45%. The mandible V50, V55, and V60 were significantly lower for the IMRT plans. Maximum spinal cord and brain stem doses were similar for the 2 techniques. IMRT provided superior target volume dose homogeneity and sparing of organs at risk. The magnitude of reductions in dose to the salivary glands and mandible are likely to translate into reduced incidence of xerostomia and osteoradionecrosis for patients with OCC.

  17. Phase I Trial of Hypofractionated Intensity-Modulated Radiotherapy With Temozolomide Chemotherapy for Patients With Newly Diagnosed Glioblastoma Multiforme

    SciTech Connect

    Chen Changhu; Damek, Denise; Gaspar, Laurie E.; Waziri, Allen; Lillehei, Kevin; Kleinschmidt-DeMasters, B.K.; Robischon, Monica; Stuhr, Kelly; Rusthoven, Kyle E.; Kavanagh, Brian D.

    2011-11-15

    Purpose: To determine the maximal tolerated biologic dose intensification of radiotherapy using fractional dose escalation with temozolomide (TMZ) chemotherapy in patients with newly diagnosed glioblastoma multiforme. Methods and Materials: Patients with newly diagnosed glioblastoma multiforme after biopsy or resection and with adequate performance status, bone marrow, and organ function were eligible. The patients underwent postoperative intensity-modulated radiotherapy (IMRT) with concurrent and adjuvant TMZ. All patients received a total dose of 60 Gy to the surgical cavity and residual tumor, with a 5-mm margin. IMRT biologic dose intensification was achieved by escalating from 3 Gy/fraction (Level 1) to 6 Gy/fraction (Level 4) in 1-Gy increments. Concurrent TMZ was given at 75 mg/m{sup 2}/d for 28 consecutive days. Adjuvant TMZ was given at 150-200 mg/m{sup 2}/d for 5 days every 28 days. Dose-limiting toxicity was defined as any Common Terminology Criteria for Adverse Events, version 3, Grade 3-4 nonhematologic toxicity, excluding Grade 3 fatigue, nausea, and vomiting. A standard 3+3 Phase I design was used. Results: A total of 16 patients were accrued (12 men and 4 women, median age, 69 years; range, 34-84. The median Karnofsky performance status was 80 (range, 60-90). Of the 16 patients, 3 each were treated at Levels 1 and 2, 4 at Level 3, and 6 at Level 4. All patients received IMRT and concurrent TMZ according to the protocol, except for 1 patient, who received 14 days of concurrent TMZ. The median number of adjuvant TMZ cycles was 7.5 (range, 0-12). The median survival was 16.2 months (range, 3-33). One patient experienced vision loss in the left eye 7 months after IMRT. Four patients underwent repeat surgery for suspected tumor recurrence 6-12 months after IMRT; 3 had radionecrosis. Conclusions: The maximal tolerated IMRT fraction size was not reached in our study. Our results have shown that 60 Gy IMRT delivered in 6-Gy fractions within 2 weeks with

  18. Intensity-Modulated Radiotherapy Reduces Gastrointestinal Toxicity in Patients Treated With Androgen Deprivation Therapy for Prostate Cancer

    SciTech Connect

    Sharma, Navesh K.; Li Tianyu; Chen, David Y.; Pollack, Alan; Horwitz, Eric M.; Buyyounouski, Mark K.

    2011-06-01

    Purpose: Androgen deprivation therapy (AD) has been shown to increase late Grade 2 or greater rectal toxicity when used concurrently with three-dimensional conformal radiotherapy (3D-CRT). Intensity-modulated radiotherapy (IMRT) has the potential to reduce toxicity by limiting the radiation dose received by the bowel and bladder. The present study compared the genitourinary and gastrointestinal (GI) toxicity in men treated with 3D-CRT+AD vs. IMRT+AD. Methods and Materials: Between July 1992 and July 2004, 293 men underwent 3D-CRT (n = 170) or IMRT (n = 123) with concurrent AD (<6 months, n = 123; {>=}6 months, n = 170). The median radiation dose was 76 Gy for 3D-CRT (International Commission on Radiation Units and Measurements) and 76 Gy for IMRT (95% to the planning target volume). Toxicity was assessed by a patient symptom questionnaire that was completed at each visit and recorded using a Fox Chase Modified Late Effects Normal Tissue Task radiation morbidity scale. Results: The mean follow-up was 86 months (standard deviation, 29.3) for the 3D-CRT group and 40 months (standard deviation, 9.7) for the IMRT group. Acute GI toxicity (odds ratio, 4; 95% confidence interval, 1.6-11.7; p = .005) was significantly greater with 3D-CRT than with IMRT and was independent of the AD duration (i.e., <6 vs. {>=}6 months). The interval to the development of late GI toxicity was significantly longer in the IMRT group. The 5-year Kaplan-Meier estimate for Grade 2 or greater GI toxicity was 20% for 3D-CRT and 8% for IMRT (p = .01). On multivariate analysis, Grade 2 or greater late GI toxicity (hazard ratio, 2.1; 95% confidence interval, 1.1-4.3; p = .04) was more prevalent in the 3D-CRT patients. Conclusion: Compared with 3D-CRT, IMRT significantly decreased the acute and late GI toxicity in patients treated with AD.

  19. Reducing the Risk of Xerostomia and Mandibular Osteoradionecrosis: The Potential Benefits of Intensity Modulated Radiotherapy in Advanced Oral Cavity Carcinoma

    SciTech Connect

    Ahmed, Merina; Hansen, Vibeke N.; Harrington, Kevin J.; Nutting, Christopher M.

    2009-10-01

    Radiation therapy for squamous cell carcinoma of the oral cavity may be curative, but carries a risk of permanent damage to bone, salivary glands, and other soft tissues. We studied the potential of intensity modulated radiotherapy (IMRT) to improve target volume coverage, and normal tissue sparing for advanced oral cavity carcinoma (OCC). Six patients with advanced OCC requiring bilateral irradiation to the oral cavity and neck were studied. Standard 3D conformal radiotherapy (3DCRT) and inverse-planned IMRT dose distributions were compared by using dose-volume histograms. Doses to organs at risk, including spinal cord, parotid glands, and mandible, were assessed as surrogates of radiation toxicity. PTV1 mean dose was 60.8 {+-} 0.8 Gy for 3DCRT and 59.8 {+-} 0.1 Gy for IMRT (p = 0.04). PTV1 dose range was 24.7 {+-} 6 Gy for 3DCRT and 15.3 {+-} 4 Gy for IMRT (p = 0.001). PTV2 mean dose was 54.5 {+-} 0.8 Gy for 3DCRT and for IMRT was 54.2 {+-} 0.2 Gy (p = 0.34). PTV2 dose range was improved by IMRT (7.8 {+-} 3.2 Gy vs. 30.7 {+-} 12.8 Gy, p = 0.006). Homogeneity index (HI) values for PTV2 were closer to unity using IMRT (p = 0.0003). Mean parotid doses were 25.6 {+-} 2.7 Gy for IMRT and 42.0 {+-} 8.8 Gy with 3DCRT (p = 0.002). The parotid V30 in all IMRT plans was <45%. The mandible V50, V55, and V60 were significantly lower for the IMRT plans. Maximum spinal cord and brain stem doses were similar for the 2 techniques. IMRT provided superior target volume dose homogeneity and sparing of organs at risk. The magnitude of reductions in dose to the salivary glands and mandible are likely to translate into reduced incidence of xerostomia and osteoradionecrosis for patients with OCC.

  20. Effect of Radiotherapy and Chemotherapy on the Risk of Mucositis During Intensity-Modulated Radiation Therapy for Oropharyngeal Cancer

    SciTech Connect

    Sanguineti, Giuseppe; Sormani, Maria Pia; Marur, Shanthi; Gunn, G. Brandon; Rao, Nikhil; Cianchetti, Marco; Ricchetti, Francesco; McNutt, Todd; Wu Binbin; Forastiere, Arlene

    2012-05-01

    Purpose: To define the roles of radiotherapy and chemotherapy on the risk of Grade 3+ mucositis during intensity-modulated radiation therapy (IMRT) for oropharyngeal cancer. Methods and Materials: 164 consecutive patients treated with IMRT at two institutions in nonoverlapping treatment eras were selected. All patients were treated with a dose painting approach, three dose levels, and comprehensive bilateral neck treatment under the supervision of the same radiation oncologist. Ninety-three patients received concomitant chemotherapy (cCHT) and 14 received induction chemotherapy (iCHT). Individual information of the dose received by the oral mucosa (OM) was extracted as absolute cumulative dose-volume histogram (DVH), corrected for the elapsed treatment days and reported as weekly (w) DVH. Patients were seen weekly during treatment, and peak acute toxicity equal to or greater than confluent mucositis at any point during the course of IMRT was considered the endpoint. Results: Overall, 129 patients (78.7%) reached the endpoint. The regions that best discriminated between patients with/without Grade 3+ mucositis were found at 10.1 Gy/w (V10.1) and 21 cc (D21), along the x-axis and y-axis of the OM-wDVH, respectively. On multivariate analysis, D21 (odds ratio [OR] = 1.016, 95% confidence interval [CI], 1.009-1.023, p < 0.001) and cCHT (OR = 4.118, 95% CI, 1.659-10.217, p = 0.002) were the only independent predictors. However, V10.1 and D21 were highly correlated (rho = 0.954, p < 0.001) and mutually interchangeable. cCHT would correspond to 88.4 cGy/w to at least 21 cc of OM. Conclusions: Radiotherapy and chemotherapy act independently in determining acute mucosal toxicity; cCHT increases the risk of mucosal Grade 3 toxicity Almost-Equal-To 4 times over radiation therapy alone, and it is equivalent to an extra Almost-Equal-To 6.2 Gy to 21 cc of OM over a 7-week course.

  1. SU-E-T-608: Performance Comparison of Four Commercial Treatment Planning Systems Applied to Intensity-Modulated Radiotherapy

    SciTech Connect

    Cao, Y; Li, R; Chi, Z

    2014-06-01

    Purpose: To compare the performances of four commercial treatment planning systems (TPS) used for the intensity-modulated radiotherapy (IMRT). Methods: Ten patients of nasopharyngeal (4 cases), esophageal (3 cases) and cervical (3 cases) cancer were randomly selected from a 3-month IMRT plan pool at one radiotherapy center. For each patient, four IMRT plans were newly generated by using four commercial TPS (Corvus, Monaco, Pinnacle and Xio), and then verified with Matrixx (two-dimensional array/IBA Company) on Varian23EX accelerator. A pass rate (PR) calculated from the Gamma index by OminiPro IMRT 1.5 software was evaluated at four plan verification standards (1%/1mm, 2%/2mm, 3%/3mm, 4%/4mm and 5%/5mm) for each treatment plan. Overall and multiple pairwise comparisons of PRs were statistically conducted by analysis of covariance (ANOVA) F and LSD tests among four TPSs. Results: Overall significant (p>0.05) differences of PRs were found among four TPSs with F test values of 3.8 (p=0.02), 21.1(>0.01), 14.0 (>0.01), 8.3(>0.01) at standards of 1%/1mm to 4%/4mm respectively, except at 5%/5mm standard with 2.6 (p=0.06). All means (standard deviation) of PRs at 3%/3mm of 94.3 ± 3.3 (Corvus), 98.8 ± 0.8 (Monaco), 97.5± 1.7 (Pinnacle), 98.4 ± 1.0 (Xio) were above 90% and met clinical requirement. Multiple pairwise comparisons had not demonstrated a consistent low or high pattern on either TPS. Conclusion: Matrixx dose verification results show that the validation pass rates of Monaco and Xio plans are relatively higher than those of the other two; Pinnacle plan shows slight higher pass rate than Corvus plan; lowest pass rate was achieved by the Corvus plan among these four kinds of TPS.

  2. Impact of Intensity-Modulated Radiotherapy on Health-Related Quality of Life for Head and Neck Cancer Patients: Matched-Pair Comparison with Conventional Radiotherapy

    SciTech Connect

    Graff, Pierre . E-mail: p.graff@nancy.fnclcc.fr; Lapeyre, Michel; Desandes, Emmanuel; Ortholan, Cecile; Bensadoun, Rene-Jean; Alfonsi, Marc; Maingon, Philippe; Giraud, Philippe; Bourhis, Jean; Marchesi, Vincent; Mege, Alice; Peiffert, Didier

    2007-04-01

    Purpose: To assess the benefit of intensity-modulated radiotherapy (IMRT) compared with conventional RT for the quality of life (QOL) of head and neck cancer survivors. Methods and Materials: Cross-sectional QOL measures (European Organization for Research and Treatment of Cancer QOL questionnaire C30 and head and neck cancer module) were used with a French multicenter cohort of patients cured of head and neck cancer (follow-up {>=} 1 year) who had received bilateral neck RT ({>=} 45 Gy) as a part of their initial treatment. We compared the QOL mean scores regarding RT modality (conventional RT vs. IMRT). The patients of the two groups were matched (one to one) according to the delay between the end of RT and the timing of the QOL evaluation and the T stage. Each QOL item was divided into two relevant levels of severity: 'not severe' (responses, 'not at all' and 'a little') vs. 'severe' (responses 'quite a bit' and 'very much'). The association between the type of RT and the prevalence of severe symptoms was approximated, through multivariate analysis using the prevalence odds ratio. Results: Two comparable groups (67 pairs) were available. Better scores were observed on the head and neck cancer module QOL questionnaire for the IMRT group, especially for dry mouth and sticky saliva (p < 0.0001). Severe symptoms were more frequent with conventional RT concerning saliva modifications and oral discomfort. The adjusted prevalence odds ratios were 3.17 (p = 0.04) for dry mouth, 3.16 (p = 0.02) for sticky saliva, 3.58 (p = 0.02) for pain in the mouth, 3.35 (p = 0.04) for pain in the jaw, 2.60 (p = 0.02) for difficulties opening the mouth, 2.76 (p = 0.02) for difficulties with swallowing, and 2.68 (p = 0.03) for trouble with eating. Conclusion: The QOL assessment of head and neck cancer survivors demonstrated the benefit of IMRT, particularly in the areas of salivary dysfunction and oral discomfort.

  3. Volumetric Arc Therapy and Intensity-Modulated Radiotherapy for Primary Prostate Radiotherapy With Simultaneous Integrated Boost to Intraprostatic Lesion With 6 and 18 MV: A Planning Comparison Study

    SciTech Connect

    Ost, Piet; Speleers, Bruno; De Meerleer, Gert; De Neve, Wilfried; Fonteyne, Valerie; Villeirs, Geert; De Gersem, Werner

    2011-03-01

    Purpose: The aim of the present study was to compare intensity-modulated radiotherapy (IMRT) with volumetric arc therapy (VMAT), in the treatment of prostate cancer with maximal dose escalation to the intraprostatic lesion (IPL), without violating the organ-at-risk constraints. Additionally, the use of 6-MV photons was compared with 18-MV photons for all techniques. Methods and Materials: A total of 12 consecutive prostate cancer patients with an IPL on magnetic resonance imaging were selected for the present study. Plans were made for three IMRT field setups (three, five, and seven fields) and one VMAT field setup (single arc). First, optimal plans were created for every technique using biologic and physical planning aims. Next, an additional escalation to the IPL was planned as high as possible without violating the planning aims of the first step. Results: No interaction between the technique and photon energy (p = .928) occurred. No differences were found between the 6- and 18-MV photon beams, except for a reduction in the number of monitor units needed for 18 MV (p < .05). All techniques, except for three-field IMRT, allowed for dose escalation to a median dose of {>=}93 {+-} 6 Gy (mean {+-} standard deviation) to the IPL. VMAT was superior to IMRT for rectal volumes receiving 20-50 Gy (p < .05). Conclusion: VMAT allowed for dose escalation to the IPL with better sparing of the rectum than static three-, five-, and seven-field IMRT setups. High-energy photons had no advantage over low-energy photons.

  4. Dosimetric and radiobiological characterizations of prostate intensity-modulated radiotherapy and volumetric-modulated arc therapy: A single-institution review of ninety cases

    PubMed Central

    Khan, Muhammad Isa; Jiang, Runqing; Kiciak, Alexander; ur Rehman, Jalil; Afzal, Muhammad; Chow, James C. L.

    2016-01-01

    This study reviewed prostate volumetric-modulated arc therapy (VMAT) plans with intensity-modulated radiotherapy (IMRT) plans after prostate IMRT technique was replaced by VMAT in an institution. Characterizations of dosimetry and radiobiological variation in prostate were determined based on treatment plans of 40 prostate IMRT patients (planning target volume = 77.8–335 cm3) and 50 VMAT patients (planning target volume = 120–351 cm3) treated before and after 2013, respectively. Both IMRT and VMAT plans used the same dose-volume criteria in the inverse planning optimization. Dose-volume histogram, mean doses of target and normal tissues (rectum, bladder and femoral heads), dose-volume points (D99% of planning target volume; D30%, D50%, V30 Gy and V35 Gy of rectum and bladder; D5%, V14 Gy, V22 Gy of femoral heads), conformity index (CI), homogeneity index (HI), gradient index (GI), prostate tumor control probability (TCP), and rectal normal tissue complication probability (NTCP) based on the Lyman-Burman-Kutcher algorithm were calculated for each IMRT and VMAT plan. From our results, VMAT plan was found better due to its higher (1.05%) CI, lower (0.83%) HI and (0.75%) GI than IMRT. Comparing doses in normal tissues between IMRT and VMAT, it was found that IMRT mostly delivered higher doses of about 1.05% to the normal tissues than VMAT. Prostate TCP and rectal NTCP were found increased (1%) for VMAT than IMRT. It is seen that VMAT technique can decrease the dose-volume evaluation criteria for the normal tissues. Based on our dosimetric and radiobiological results in treatment plans, it is concluded that our VMAT implementation could produce comparable or slightly better target coverage and normal tissue sparing with a faster treatment time in prostate radiotherapy. PMID:27651562

  5. Dosimetric and radiobiological characterizations of prostate intensity-modulated radiotherapy and volumetric-modulated arc therapy: A single-institution review of ninety cases.

    PubMed

    Khan, Muhammad Isa; Jiang, Runqing; Kiciak, Alexander; Ur Rehman, Jalil; Afzal, Muhammad; Chow, James C L

    2016-01-01

    This study reviewed prostate volumetric-modulated arc therapy (VMAT) plans with intensity-modulated radiotherapy (IMRT) plans after prostate IMRT technique was replaced by VMAT in an institution. Characterizations of dosimetry and radiobiological variation in prostate were determined based on treatment plans of 40 prostate IMRT patients (planning target volume = 77.8-335 cm(3)) and 50 VMAT patients (planning target volume = 120-351 cm(3)) treated before and after 2013, respectively. Both IMRT and VMAT plans used the same dose-volume criteria in the inverse planning optimization. Dose-volume histogram, mean doses of target and normal tissues (rectum, bladder and femoral heads), dose-volume points (D99% of planning target volume; D30%, D50%, V30 Gy and V35 Gy of rectum and bladder; D5%, V14 Gy, V22 Gy of femoral heads), conformity index (CI), homogeneity index (HI), gradient index (GI), prostate tumor control probability (TCP), and rectal normal tissue complication probability (NTCP) based on the Lyman-Burman-Kutcher algorithm were calculated for each IMRT and VMAT plan. From our results, VMAT plan was found better due to its higher (1.05%) CI, lower (0.83%) HI and (0.75%) GI than IMRT. Comparing doses in normal tissues between IMRT and VMAT, it was found that IMRT mostly delivered higher doses of about 1.05% to the normal tissues than VMAT. Prostate TCP and rectal NTCP were found increased (1%) for VMAT than IMRT. It is seen that VMAT technique can decrease the dose-volume evaluation criteria for the normal tissues. Based on our dosimetric and radiobiological results in treatment plans, it is concluded that our VMAT implementation could produce comparable or slightly better target coverage and normal tissue sparing with a faster treatment time in prostate radiotherapy.

  6. Dosimetric and radiobiological characterizations of prostate intensity-modulated radiotherapy and volumetric-modulated arc therapy: A single-institution review of ninety cases.

    PubMed

    Khan, Muhammad Isa; Jiang, Runqing; Kiciak, Alexander; Ur Rehman, Jalil; Afzal, Muhammad; Chow, James C L

    2016-01-01

    This study reviewed prostate volumetric-modulated arc therapy (VMAT) plans with intensity-modulated radiotherapy (IMRT) plans after prostate IMRT technique was replaced by VMAT in an institution. Characterizations of dosimetry and radiobiological variation in prostate were determined based on treatment plans of 40 prostate IMRT patients (planning target volume = 77.8-335 cm(3)) and 50 VMAT patients (planning target volume = 120-351 cm(3)) treated before and after 2013, respectively. Both IMRT and VMAT plans used the same dose-volume criteria in the inverse planning optimization. Dose-volume histogram, mean doses of target and normal tissues (rectum, bladder and femoral heads), dose-volume points (D99% of planning target volume; D30%, D50%, V30 Gy and V35 Gy of rectum and bladder; D5%, V14 Gy, V22 Gy of femoral heads), conformity index (CI), homogeneity index (HI), gradient index (GI), prostate tumor control probability (TCP), and rectal normal tissue complication probability (NTCP) based on the Lyman-Burman-Kutcher algorithm were calculated for each IMRT and VMAT plan. From our results, VMAT plan was found better due to its higher (1.05%) CI, lower (0.83%) HI and (0.75%) GI than IMRT. Comparing doses in normal tissues between IMRT and VMAT, it was found that IMRT mostly delivered higher doses of about 1.05% to the normal tissues than VMAT. Prostate TCP and rectal NTCP were found increased (1%) for VMAT than IMRT. It is seen that VMAT technique can decrease the dose-volume evaluation criteria for the normal tissues. Based on our dosimetric and radiobiological results in treatment plans, it is concluded that our VMAT implementation could produce comparable or slightly better target coverage and normal tissue sparing with a faster treatment time in prostate radiotherapy. PMID:27651562

  7. Dosimetric and radiobiological characterizations of prostate intensity-modulated radiotherapy and volumetric-modulated arc therapy: A single-institution review of ninety cases

    PubMed Central

    Khan, Muhammad Isa; Jiang, Runqing; Kiciak, Alexander; ur Rehman, Jalil; Afzal, Muhammad; Chow, James C. L.

    2016-01-01

    This study reviewed prostate volumetric-modulated arc therapy (VMAT) plans with intensity-modulated radiotherapy (IMRT) plans after prostate IMRT technique was replaced by VMAT in an institution. Characterizations of dosimetry and radiobiological variation in prostate were determined based on treatment plans of 40 prostate IMRT patients (planning target volume = 77.8–335 cm3) and 50 VMAT patients (planning target volume = 120–351 cm3) treated before and after 2013, respectively. Both IMRT and VMAT plans used the same dose-volume criteria in the inverse planning optimization. Dose-volume histogram, mean doses of target and normal tissues (rectum, bladder and femoral heads), dose-volume points (D99% of planning target volume; D30%, D50%, V30 Gy and V35 Gy of rectum and bladder; D5%, V14 Gy, V22 Gy of femoral heads), conformity index (CI), homogeneity index (HI), gradient index (GI), prostate tumor control probability (TCP), and rectal normal tissue complication probability (NTCP) based on the Lyman-Burman-Kutcher algorithm were calculated for each IMRT and VMAT plan. From our results, VMAT plan was found better due to its higher (1.05%) CI, lower (0.83%) HI and (0.75%) GI than IMRT. Comparing doses in normal tissues between IMRT and VMAT, it was found that IMRT mostly delivered higher doses of about 1.05% to the normal tissues than VMAT. Prostate TCP and rectal NTCP were found increased (1%) for VMAT than IMRT. It is seen that VMAT technique can decrease the dose-volume evaluation criteria for the normal tissues. Based on our dosimetric and radiobiological results in treatment plans, it is concluded that our VMAT implementation could produce comparable or slightly better target coverage and normal tissue sparing with a faster treatment time in prostate radiotherapy.

  8. Predictors of Local Control After Single-Dose Stereotactic Image-Guided Intensity-Modulated Radiotherapy for Extracranial Metastases

    SciTech Connect

    Greco, Carlo; Zelefsky, Michael J.; Lovelock, Michael; Fuks, Zvi; Hunt, Margie; Rosenzweig, Kenneth; Zatcky, Joan; Kim, Balem; Yamada, Yoshiya

    2011-03-15

    Purpose: To report tumor local control after treatment with single-dose image-guided intensity-modulated radiotherapy (SD-IGRT) to extracranial metastatic sites. Methods and Materials: A total of 126 metastases in 103 patients were treated with SD-IGRT to prescription doses of 18-24 Gy (median, 24 Gy) between 2004 and 2007. Results: The overall actuarial local relapse-free survival (LRFS) rate was 64% at a median follow-up of 18 months (range, 2-45 months). The median time to failure was 9.6 months (range, 1-23 months). On univariate analysis, LRFS was significantly correlated with prescription dose (p = 0.029). Stratification by dose into high (23 to 24 Gy), intermediate (21 to 22 Gy), and low (18 to 20 Gy) dose levels revealed highly significant differences in LRFS between high (82%) and low doses (25%) (p < 0.0001). Overall, histology had no significant effect on LRFS (p = 0.16). Renal cell histology displayed a profound dose-response effect, with 80% LRFS at the high dose level (23 to 24 Gy) vs. 37% with low doses ({<=}22 Gy) (p = 0.04). However, for patients who received the high dose level, histology was not a statistically significant predictor of LRFS (p = 0.90). Target organ (bone vs. lymph node vs. soft tissues) (p = 0.5) and planning target volume size (p = 0.55) were not found to be associated with long-term LRFS probability. Multivariate Cox regression analysis confirmed prescription dose to be a significant predictor of LRFS (p = 0.003). Conclusion: High-dose SD-IGRT is a noninvasive procedure resulting in high probability of local tumor control. Single-dose IGRT may be effectively used to locally control metastatic deposits regardless of histology and target organ, provided sufficiently high doses (> 22 Gy) of radiation are delivered.

  9. Early Clinical Outcome With Concurrent Chemotherapy and Extended-Field, Intensity-Modulated Radiotherapy for Cervical Cancer

    SciTech Connect

    Beriwal, Sushil . E-mail: beriwals@upmc.edu; Gan, Gregory N.; Heron, Dwight E.; Selvaraj, Raj N.; Kim, Hayeon; Lalonde, Ron; Kelley, Joseph L.; Edwards, Robert P.

    2007-05-01

    Purpose: To assess the early clinical outcomes with concurrent cisplatin and extended-field intensity-modulated radiotherapy (EF-IMRT) for carcinoma of the cervix. Methods and Materials: Thirty-six patients with Stage IB2-IVA cervical cancer treated with EF-IMRT were evaluated. The pelvic lymph nodes were involved in 19 patients, and of these 19 patients, 10 also had para-aortic nodal disease. The treatment volume included the cervix, uterus, parametria, presacral space, upper vagina, and pelvic, common iliac, and para-aortic nodes to the superior border of L1. Patients were assessed for acute toxicities according to the National Cancer Institute Common Toxicity Criteria for Adverse Events, version 3.0. All late toxicities were scored with the Radiation Therapy Oncology Group late toxicity score. Results: All patients completed the prescribed course of EF-IMRT. All but 2 patients received brachytherapy. Median length of treatment was 53 days. The median follow-up was 18 months. Acute Grade {>=}3 gastrointestinal, genitourinary, and myelotoxicity were seen in 1, 1, and 10 patients, respectively. Thirty-four patients had complete response to treatment. Of these 34 patients, 11 developed recurrences. The first site of recurrence was in-field in 2 patients (pelvis in 1, pelvis and para-aortic in 1) and distant in 9 patients. The 2-year actuarial locoregional control, disease-free survival, overall survival, and Grade {>=}3 toxicity rates for the entire cohort were 80%, 51%, 65%, and 10%, respectively. Conclusion: Extended-field IMRT with concurrent chemotherapy was tolerated well, with acceptable acute and early late toxicities. The locoregional control rate was good, with distant metastases being the predominant mode of failure. We are continuing to accrue a larger number of patients and longer follow-up data to further extend our initial observations with this approach.

  10. Intensity-Modulated Radiotherapy for Tumors of the Nasal Cavity and Paranasal Sinuses: Clinical Outcomes and Patterns of Failure

    SciTech Connect

    Wiegner, Ellen A.; Daly, Megan E.; Murphy, James D.; Abelson, Jonathan; Chapman, Chris H.; Chung, Melody; Yu, Yao; Colevas, A. Dimitrios; Kaplan, Michael J.; Fischbein, Nancy; Le, Quynh-Thu; Chang, Daniel T.

    2012-05-01

    Purpose: To report outcomes in patients treated with intensity-modulated radiotherapy (IMRT) for tumors of the paranasal sinuses and nasal cavity (PNS/NC). Methods/Materials: Between June 2000 and December 2009, 52 patients with tumors of the PNS/NC underwent postoperative or definitive radiation with IMRT. Twenty-eight (54%) patients had squamous cell carcinoma (SCC). Twenty-nine patients (56%) received chemotherapy. The median follow-up was 26.6 months (range, 2.9-118.4) for all patients and 30.9 months for living patients. Results: Eighteen patients (35%) developed local-regional failure (LRF) at median time of 7.2 months. Thirteen local failures (25%) were observed, 12 in-field and 1 marginal. Six regional failures were observed, two in-field and four out-of-field. No patients treated with elective nodal radiation had nodal regional failure. Two-year local-regional control (LRC), in-field LRC, freedom from distant metastasis (FFDM), and overall survival (OS) were 64%, 74%, 71%, and 66% among all patients, respectively, and 43%, 61%, 61%, and 53% among patients with SCC, respectively. On multivariate analysis, SCC and >1 subsite involved had worse LRC (p = 0.0004 and p = 0.046, respectively) and OS (p = 0.003 and p = 0.046, respectively). Cribriform plate invasion (p = 0.005) and residual disease (p = 0.047) also had worse LRC. Acute toxicities included Grade {>=}3 mucositis in 19 patients (37%), and Grade 3 dermatitis in 8 patients (15%). Six patients had Grade {>=}3 late toxicity including one optic toxicity. Conclusions: IMRT for patients with PNS/NC tumors has good outcomes compared with historical series and is well tolerated. Patients with SCC have worse LRC and OS. LRF is the predominant pattern of failure.

  11. Dosimetric Comparison of Bone Marrow-Sparing Intensity-Modulated Radiotherapy Versus Conventional Techniques for Treatment of Cervical Cancer

    SciTech Connect

    Mell, Loren K.; Tiryaki, Hanifi; Ahn, Kang-Hyun; Mundt, Arno J.; Roeske, John C.; Aydogan, Bulent

    2008-08-01

    Purpose: To compare bone marrow-sparing intensity-modulated pelvic radiotherapy (BMS-IMRT) with conventional (four-field box and anteroposterior-posteroanterior [AP-PA]) techniques in the treatment of cervical cancer. Methods and Materials: The data from 7 cervical cancer patients treated with concurrent chemotherapy and IMRT without BMS were analyzed and compared with data using four-field box and AP-PA techniques. All plans were normalized to cover the planning target volume with the 99% isodose line. The clinical target volume consisted of the pelvic and presacral lymph nodes, uterus and cervix, upper vagina, and parametrial tissue. Normal tissues included bowel, bladder, and pelvic bone marrow (PBM), which comprised the lumbosacral spine and ilium and the ischium, pubis, and proximal femora (lower pelvis bone marrow). Dose-volume histograms for the planning target volume and normal tissues were compared for BMS-IMRT vs. four-field box and AP-PA plans. Results: BMS-IMRT was superior to the four-field box technique in reducing the dose to the PBM, small bowel, rectum, and bladder. Compared with AP-PA plans, BMS-IMRT reduced the PBM volume receiving a dose >16.4 Gy. BMS-IMRT reduced the volume of ilium, lower pelvis bone marrow, and bowel receiving a dose >27.7, >18.7, and >21.1 Gy, respectively, but increased dose below these thresholds compared with the AP-PA plans. BMS-IMRT reduced the volume of lumbosacral spine bone marrow, rectum, small bowel, and bladder at all dose levels in all 7 patients. Conclusion: BMS-IMRT reduced irradiation of PBM compared with the four-field box technique. Compared with the AP-PA technique, BMS-IMRT reduced lumbosacral spine bone marrow irradiation and reduced the volume of PBM irradiated to high doses. Therefore BMS-IMRT might reduce acute hematologic toxicity compared with conventional techniques.

  12. Relationship Between Pelvic Organ-at-Risk Dose and Clinical Target Volume in Postprostatectomy Patients Receiving Intensity-Modulated Radiotherapy

    SciTech Connect

    Stanic, Sinisa; Mathai, Mathew; Cui Jing; Purdy, James A.; Valicenti, Richard K.

    2012-04-01

    Purpose: To investigate dose-volume consequences of inclusion of the seminal vesicle (SV) bed in the clinical target volume (CTV) for the rectum and bladder using biological response indices in postprostatectomy patients receiving intensity-modulated radiotherapy (IMRT). Methods and Materials: We studied 10 consecutive patients who underwent prostatectomy for prostate cancer and subsequently received adjuvant or salvage RT to the prostate fossa. The CTV to planning target volume (PTV) expansion was 7 mm, except posterior expansion, which was 5 mm. Two IMRT plans were generated for each patient, including either the prostate fossa alone or the prostate fossa with the SV bed, but identical in all other aspects. Prescription dose was 68.4 Gy in 1.8-Gy fractions prescribed to {>=}95% PTV. Results: With inclusion of the SV bed in the treatment volume, PTV increased and correlated with PTV-bladder and PTV-rectum volume overlap (Spearman {rho} 0.91 and 0.86, respectively; p < 0.05). As a result, the dose delivered to the bladder and rectum was higher (p < 0.05): mean bladder dose increased from 11.3 {+-} 3.5 Gy to 21.2 {+-} 6.6 Gy, whereas mean rectal dose increased from 25.8 {+-} 5.5 Gy to 32.3 {+-} 5.5 Gy. Bladder and rectal equivalent uniform dose correlated with mean bladder and rectal dose. Inclusion of the SV bed in the treatment volume increased rectal normal tissue complication probability from 2.4% to 4.8% (p < 0.01). Conclusions: Inclusion of the SV bed in the CTV in postprostatectomy patients receiving IMRT increases bladder and rectal dose, as well as rectal normal tissue complication probability. The magnitude of PTV-bladder and PTV-rectal volume overlap and subsequent bladder and rectum dose increase will be higher if larger PTV expansion margins are used.

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

    SciTech Connect

    Ng, Michael; Leong, Trevor; Chander, Sarat; Chu, Julie; Kneebone, Andrew; Carroll, Susan; Wiltshire, Kirsty; Ngan, Samuel; Kachnic, Lisa

    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.

  14. Acute Toxicity in High-Risk Prostate Cancer Patients Treated With Androgen Suppression and Hypofractionated Intensity-Modulated Radiotherapy

    SciTech Connect

    Pervez, Nadeem; Small, Cormac; MacKenzie, Marc; Yee, Don; Parliament, Matthew; Ghosh, Sunita; Mihai, Alina; Amanie, John; Murtha, Albert; Field, Colin; Murray, David; Fallone, Gino; Pearcey, Robert

    2010-01-15

    Purpose: To report acute toxicity resulting from radiotherapy (RT) dose escalation and hypofractionation using intensity-modulated RT (IMRT) treatment combined with androgen suppression in high-risk prostate cancer patients. Methods and Materials: Sixty patients with a histological diagnosis of high-risk prostatic adenocarcinoma (having either a clinical Stage of >=T3a or an initial prostate-specific antigen [PSA] level of >=20 ng/ml or a Gleason score of 8 to 10 or a combination of a PSA concentration of >15 ng/ml and a Gleason score of 7) were enrolled. RT prescription was 68 Gy in 25 fractions (2.72 Gy/fraction) over 5 weeks to the prostate and proximal seminal vesicles. The pelvic lymph nodes and distal seminal vesicles concurrently received 45 Gy in 25 fractions. The patients were treated with helical TomoTherapy-based IMRT and underwent daily megavoltage CT image-guided verification prior to each treatment. Acute toxicity scores were recorded weekly during RT and at 3 months post-RT, using Radiation Therapy Oncology Group acute toxicity scales. Results: All patients completed RT and follow up for 3 months. The maximum acute toxicity scores were as follows: 21 (35%) patients had Grade 2 gastrointestinal (GI) toxicity; 4 (6.67%) patients had Grade 3 genitourinary (GU) toxicity; and 30 (33.33%) patients had Grade 2 GU toxicity. These toxicity scores were reduced after RT; there were only 8 (13.6%) patients with Grade 1 GI toxicity, 11 (18.97%) with Grade 1 GU toxicity, and 5 (8.62%) with Grade 2 GU toxicity at 3 months follow up. Only the V60 to the rectum correlated with the GI toxicity. Conclusion: Dose escalation using a hypofractionated schedule to the prostate with concurrent pelvic lymph node RT and long-term androgen suppression therapy is well tolerated acutely. Longer follow up for outcome and late toxicity is required.

  15. Preliminary analysis of the sequential simultaneous integrated boost technique for intensity-modulated radiotherapy for head and neck cancers

    PubMed Central

    Miyazaki, Masayoshi; Nishiyama, Kinji; Ueda, Yoshihiro; Ohira, Shingo; Tsujii, Katsutomo; Isono, Masaru; Masaoka, Akira; Teshima, Teruki

    2016-01-01

    The aim of this study was to compare three strategies for intensity-modulated radiotherapy (IMRT) for 20 head-and-neck cancer patients. For simultaneous integrated boost (SIB), doses were 66 and 54 Gy in 30 fractions for PTVboost and PTVelective, respectively. Two-phase IMRT delivered 50 Gy in 25 fractions to PTVelective in the First Plan, and 20 Gy in 10 fractions to PTVboost in the Second Plan. Sequential SIB (SEQ-SIB) delivered 55 Gy and 50 Gy in 25 fractions, respectively, to PTVboost and PTVelective using SIB in the First Plan and 11 Gy in 5 fractions to PTVboost in the Second Plan. Conformity indexes (CIs) (mean ± SD) for PTVboost and PTVelective were 1.09 ± 0.05 and 1.34 ± 0.12 for SIB, 1.39 ± 0.14 and 1.80 ± 0.28 for two-phase IMRT, and 1.14 ± 0.07 and 1.60 ± 0.18 for SEQ-SIB, respectively. CI was significantly highest for two-phase IMRT. Maximum doses (Dmax) to the spinal cord were 42.1 ± 1.5 Gy for SIB, 43.9 ± 1.0 Gy for two-phase IMRT and 40.3 ± 1.8 Gy for SEQ-SIB. Brainstem Dmax were 50.1 ± 2.2 Gy for SIB, 50.5 ± 4.6 Gy for two-phase IMRT and 47.4 ± 3.6 Gy for SEQ-SIB. Spinal cord Dmax for the three techniques was significantly different, and brainstem Dmax was significantly lower for SEQ-SIB. The compromised conformity of two-phase IMRT can result in higher doses to organs at risk (OARs). Lower OAR doses in SEQ-SIB made SEQ-SIB an alternative to SIB, which applies unconventional doses per fraction. PMID:26983983

  16. Modeling secondary cancer risk following paediatric radiotherapy: a comparison of intensity modulated proton therapy and photon therapy

    NASA Astrophysics Data System (ADS)

    Shin, Naomi

    Proton radiotherapy is known to reduce the radiation dose delivered to normal healthy tissue compared to photon techniques. The increase in normal tissue sparing could result in fewer acute and late effects from radiation therapy. In this work proton therapy plans were created for patients previously treated using photon therapy. Intensity modulated proton therapy (IMPT) plans were planned using inverse planning in VarianRTM's Eclipse(TM) treatment planning system with a scanning proton beam model to the same relative biological effectiveness (RBE)-weighted prescription dose as the photon plan. Proton and photon plans were compared for target dose conformity and homogeneity, body volumes receiving 2 Gy and 5 Gy, integral dose, dose to normal tissues and second cancer risk. Secondary cancer risk was determined using two methods. The relative risk of secondary cancer was found using the method described by Nguyen et al. 1 by applying a linear relationship between integral dose and relative risk of secondary cancer. The second approach used Schneider et al. 's organ equivalent dose concept to describe the dose in the body and then calculate the excess absolute risk and cumulative risk for solid cancers in the body. IMPT and photon plans had similar target conformity and homogeneity. However IMPT plans had reduced integral dose and volumes of the body receiving low dose. Overall the risk of radiation induced secondary cancer was lower for IMPT plans compared to the corresponding photon plans with a reduction of ~36% using the integral dose model and ˜50% using the organ equivalent dose model. *Please refer to dissertation for footnotes.

  17. Quality assurance for radiotherapy in prostate cancer: Point dose measurements in intensity modulated fields with large dose gradients

    SciTech Connect

    Escude, Lluis . E-mail: lluis.escude@gmx.net; Linero, Dolors; Molla, Meritxell; Miralbell, Raymond

    2006-11-15

    Purpose: We aimed to evaluate an optimization algorithm designed to find the most favorable points to position an ionization chamber (IC) for quality assurance dose measurements of patients treated for prostate cancer with intensity-modulated radiotherapy (IMRT) and fields up to 10 cm x 10 cm. Methods and Materials: Three cylindrical ICs (PTW, Freiburg, Germany) were used with volumes of 0.6 cc, 0.125 cc, and 0.015 cc. Dose measurements were made in a plastic phantom (PMMA) at 287 optimized points. An algorithm was designed to search for points with the lowest dose gradient. Measurements were made also at 39 nonoptimized points. Results were normalized to a reference homogeneous field introducing a dose ratio factor, which allowed us to compare measured vs. calculated values as percentile dose ratio factor deviations {delta}F (%). A tolerance range of {delta}F (%) of {+-}3% was considered. Results: Half of the {delta}F (%) values obtained at nonoptimized points were outside the acceptable range. Values at optimized points were widely spread for the largest IC (i.e., 60% of the results outside the tolerance range), whereas for the two small-volume ICs, only 14.6% of the results were outside the tolerance interval. No differences were observed when comparing the two small ICs. Conclusions: The presented optimization algorithm is a useful tool to determine the best IC in-field position for optimal dose measurement conditions. A good agreement between calculated and measured doses can be obtained by positioning small volume chambers at carefully selected points in the field. Large chambers may be unreliable even in optimized points for IMRT fields {<=}10 cm x 10 cm.

  18. Intensity-Modulated Radiotherapy for Oral Cavity Squamous Cell Carcinoma: Patterns of Failure and Predictors of Local Control

    SciTech Connect

    Daly, Megan E.; Le, Quynh-Thu; Kozak, Margaret M.; Maxim, Peter G.; Murphy, James D.; Hsu, Annie; Loo, Billy W.; Kaplan, Michael J.; Fischbein, Nancy J.; Chang, Daniel T.

    2011-08-01

    Purpose: Few studies have evaluated the use of intensity-modulated radiotherapy (IMRT) for squamous cell carcinoma (SCC) of the oral cavity (OC). We report clinical outcomes and failure patterns for these patients. Methods and Materials: Between October 2002 and June 2009, 37 patients with newly diagnosed SCC of the OC underwent postoperative (30) or definitive (7) IMRT. Twenty-five patients (66%) received systemic therapy. The median follow-up was 38 months (range, 10-87 months). The median interval from surgery to RT was 5.9 weeks (range, 2.1-10.7 weeks). Results: Thirteen patients experienced local-regional failure at a median of 8.1 months (range, 2.4-31.9 months), and 2 additional patients experienced local recurrence between surgery and RT. Seven local failures occurred in-field (one with simultaneous nodal and distant disease) and two at the margin. Four regional failures occurred, two in-field and two out-of-field, one with synchronous metastases. Six patients experienced distant failure. The 3-year actuarial estimates of local control, local-regional control, freedom from distant metastasis, and overall survival were 67%, 53%, 81%, and 60% among postoperative patients, respectively, and 60%, 60%, 71%, and 57% among definitive patients. Four patients developed Grade {>=}2 chronic toxicity. Increased surgery to RT interval predicted for decreased LRC (p = 0.04). Conclusions: Local-regional control for SCC of the OC treated with IMRT with or without surgery remains unsatisfactory. Definitive and postoperative IMRT have favorable toxicity profiles. A surgery-to-RT interval of <6 weeks improves local-regional control. The predominant failure pattern was local, suggesting that both improvements in target delineation and radiosensitization and/or dose escalation are needed.

  19. Volumetric tumor burden and its effect on brachial plexus dosimetry in head and neck intensity-modulated radiotherapy

    SciTech Connect

    Romesser, Paul B.; Qureshi, Muhammad M.; Kovalchuk, Nataliya; Truong, Minh Tam

    2014-07-01

    To determine the effect of gross tumor volume of the primary (GTV-P) and nodal (GTV-N) disease on planned radiation dose to the brachial plexus (BP) in head and neck intensity-modulated radiotherapy (IMRT). Overall, 75 patients underwent definitive IMRT to a median total dose of 69.96 Gy in 33 fractions. The right BP and left BP were prospectively contoured as separate organs at risk. The GTV was related to BP dose using the unpaired t-test. Receiver operating characteristics curves were constructed to determine optimized volumetric thresholds of GTV-P and GTV-N corresponding to a maximum BP dose cutoff of > 66 Gy. Multivariate analyses were performed to account for factors associated with a higher maximal BP dose. A higher maximum BP dose (> 66 vs ≤ 66 Gy) correlated with a greater mean GTV-P (79.5 vs 30.8 cc; p = 0.001) and ipsilateral GTV-N (60.6 vs 19.8 cc; p = 0.014). When dichotomized by the optimized nodal volume, patients with an ipsilateral GTV-N ≥ 4.9 vs < 4.9 cc had a significant difference in maximum BP dose (64.2 vs 59.4 Gy; p = 0.001). Multivariate analysis confirmed that an ipsilateral GTV-N ≥ 4.9 cc was an independent predictor for the BP to receive a maximal dose of > 66 Gy when adjusted individually for BP volume, GTV-P, the use of a low anterior neck field technique, total planned radiation dose, and tumor category. Although both the primary and the nodal tumor volumes affected the BP maximal dose, the ipsilateral nodal tumor volume (GTV-N ≥ 4.9 cc) was an independent predictor for high maximal BP dose constraints in head and neck IMRT.

  20. The efficacy and toxicity of individualized intensity-modulated radiotherapy based on the tumor extension patterns of nasopharyngeal carcinoma

    PubMed Central

    Zhou, Guan-Qun; Guo, Rui; Zhang, Fan; Zhang, Yuan; Xu, Lin; Zhang, Lu-Lu; Lin, Ai-Hua; Ma, Jun; Sun, Ying

    2016-01-01

    Background To evaluate the efficacy and toxicity of intensity-modulated radiotherapy (IMRT) using individualized clinical target volumes (CTVs) based on the loco-regional extension patterns of nasopharyngeal carcinoma (NPC). Methods From December 2009 to February 2012, 220 patients with histologically-proven, non-disseminated NPC were prospectively treated with IMRT according to an individualized delineation protocol. CTV1 encompassed the gross tumor volume, entire nasopharyngeal mucosa and structures within the pharyngobasilar fascia with a margin. CTV2 encompassed bilateral high risk anatomic sites and downstream anatomic sites adjacent to primary tumor, bilateral retropharyngeal regions, levels II, III and Va, and prophylactic irradiation was gave to one or two levels beyond clinical lymph nodes involvement. Clinical outcomes and toxicities were evaluated. Results Median follow-up was 50.8 (range, 1.3–68.0) months, four-year local relapse-free, regional relapse-free, distant metastasis-free, disease-free and overall survival rates were 94.7%, 97.0%, 91.7%, 87.2% and 91.9%, respectively. Acute severe (≥ grade 3) mucositis, dermatitis and xerostomia were observed in 27.6%, 3.6% and zero patients, respectively. At 1 year, xerostomia was mild, with frequencies of Grade 0, 1, 2 and 3 xerostomia of 27.9%, 63.3%, 8.3% and 0.5%, respectively. Conclusions IMRT using individualized CTVs provided high rates of local and regional control and a favorable toxicity profile in NPC. Individualized CTV delineation strategy is a promising one that may effectively avoid unnecessary or missed irradiation, and deserve optimization to define more precise individualized CTVs. PMID:26980744

  1. A dosimetric comparison of two-phase adaptive intensity-modulated radiotherapy for locally advanced nasopharyngeal cancer

    PubMed Central

    Chitapanarux, Imjai; Chomprasert, Kittisak; Nobnaop, Wannapa; Wanwilairat, Somsak; Tharavichitkul, Ekasit; Jakrabhandu, Somvilai; Onchan, Wimrak; Traisathit, Patrinee; Van Gestel, Dirk

    2015-01-01

    The purpose of this investigation was to evaluate the potential dosimetric benefits of a two-phase adaptive intensity-modulated radiotherapy (IMRT) protocol for patients with locally advanced nasopharyngeal cancer (NPC). A total of 17 patients with locally advanced NPC treated with IMRT had a second computed tomography (CT) scan after 17 fractions in order to apply and continue the treatment with an adapted plan after 20 fractions. To simulate the situation without adaptation, a hybrid plan was generated by applying the optimization parameters of the original treatment plan to the anatomy of the second CT scan. The dose–volume histograms (DVHs) and dose statistics of the hybrid plan and the adapted plan were compared. The mean volume of the ipsilateral and contralateral parotid gland decreased by 6.1 cm3 (30.5%) and 5.4 cm3 (24.3%), respectively. Compared with the hybrid plan, the adapted plan provided a higher dose to the target volumes with better homogeneity, and a lower dose to the organs at risk (OARs). The Dmin of all planning target volumes (PTVs) increased. The Dmax of the spinal cord and brainstem were lower in 94% of the patients (1.6–5.9 Gy, P < 0.001 and 2.1–9.9 Gy, P < 0.001, respectively). The Dmean of the contralateral parotid decreased in 70% of the patients (range, 0.2–4.4 Gy). We could not find a relationship between dose variability and weight loss. Our two-phase adaptive IMRT protocol improves dosimetric results in terms of target volumes and OARs in patients with locally advanced NPC. PMID:25666189

  2. Application of a Novel Dose-Uncertainty Model for Dose-Uncertainty Analysis in Prostate Intensity-Modulated Radiotherapy

    SciTech Connect

    Jin Hosang; Palta, Jatinder R.; Kim, You-Hyun; Kim, Siyong

    2010-11-01

    Purpose: To analyze dose uncertainty using a previously published dose-uncertainty model, and to assess potential dosimetric risks existing in prostate intensity-modulated radiotherapy (IMRT). Methods and Materials: The dose-uncertainty model provides a three-dimensional (3D) dose-uncertainty distribution in a given confidence level. For 8 retrospectively selected patients, dose-uncertainty maps were constructed using the dose-uncertainty model at the 95% CL. In addition to uncertainties inherent to the radiation treatment planning system, four scenarios of spatial errors were considered: machine only (S1), S1 + intrafraction, S1 + interfraction, and S1 + both intrafraction and interfraction errors. To evaluate the potential risks of the IMRT plans, three dose-uncertainty-based plan evaluation tools were introduced: confidence-weighted dose-volume histogram, confidence-weighted dose distribution, and dose-uncertainty-volume histogram. Results: Dose uncertainty caused by interfraction setup error was more significant than that of intrafraction motion error. The maximum dose uncertainty (95% confidence) of the clinical target volume (CTV) was smaller than 5% of the prescribed dose in all but two cases (13.9% and 10.2%). The dose uncertainty for 95% of the CTV volume ranged from 1.3% to 2.9% of the prescribed dose. Conclusions: The dose uncertainty in prostate IMRT could be evaluated using the dose-uncertainty model. Prostate IMRT plans satisfying the same plan objectives could generate a significantly different dose uncertainty because a complex interplay of many uncertainty sources. The uncertainty-based plan evaluation contributes to generating reliable and error-resistant treatment plans.

  3. Cervical Lymph Node Metastases From Unknown Primary Cancer: A Single-Institution Experience With Intensity-Modulated Radiotherapy

    SciTech Connect

    Villeneuve, Hugo; Despres, Philippe; Fortin, Bernard; Filion, Edith; Donath, David; Soulieres, Denis; Guertin, Louis; Ayad, Tarek; Christopoulos, Apostolos; Nguyen-Tan, Phuc Felix

    2012-04-01

    Purpose: To determine the effectiveness and rate of complications of intensity-modulated radiotherapy (IMRT) in the treatment of cervical lymph node metastases from unknown primary cancer. Methods and Materials: Between February 2005 and November 2008, 25 patients with an unknown primary cancer underwent IMRT, with a median radiation dose of 70 Gy. The bilateral neck and ipsilateral putative pharyngeal mucosa were included in the target volume. All patients had squamous cell carcinoma, except for 1 patient who had adenosquamous differentiation. They were all treated with curative intent. Of the 25 included patients, 20 were men and 5 were women, with a median age of 54 years. Of these patients, 3 had Stage III, 18 had Stage IVa, and 4 had Stage IVb. Of the 25 patients, 18 (72%) received platinum-based chemotherapy in a combined-modality setting. Neck dissection was reserved for residual disease after definitive IMRT. Overall survival, disease-free survival, and locoregional control were calculated using the Kaplan-Meier method. Results: With a median follow-up of 38 months, the overall survival, disease-free survival, and locoregional control rates were all 100% at 3 years. No occurrence of primary cancer was observed during the follow-up period. The reported rates of xerostomia reduced with the interval from the completion of treatment. Nine patients (36%) reported Grade 2 or greater xerostomia at 6 months, and only 2 (8%) of them reported the same grade of salivary function toxicity after 24 months of follow-up. Conclusion: In our institution, IMRT for unknown primary cancer has provided good overall and disease-free survival in all the patients with an acceptable rate of complications. IMRT allowed us to address the bilateral neck and ipsilateral putative pharyngeal mucosa with minimal late salivary function toxicity. The use of concurrent chemotherapy and IMRT for more advanced disease led to good clinical results with reasonable toxicities.

  4. DOSIMETRIC CONSEQUENCES OF USING CONTRAST-ENHANCED COMPUTED TOMOGRAPHIC IMAGES FOR INTENSITY-MODULATED STEREOTACTIC BODY RADIOTHERAPY PLANNING.

    PubMed

    Yoshikawa, Hiroto; Roback, Donald M; Larue, Susan M; Nolan, Michael W

    2015-01-01

    Potential benefits of planning radiation therapy on a contrast-enhanced computed tomography scan (ceCT) should be weighed against the possibility that this practice may be associated with an inadvertent risk of overdosing nearby normal tissues. This study investigated the influence of ceCT on intensity-modulated stereotactic body radiotherapy (IM-SBRT) planning. Dogs with head and neck, pelvic, or appendicular tumors were included in this retrospective cross-sectional study. All IM-SBRT plans were constructed on a pre- or ceCT. Contours for tumor and organs at risk (OAR) were manually constructed and copied onto both CT's; IM-SBRT plans were calculated on each CT in a manner that resulted in equal radiation fluence. The maximum and mean doses for OAR, and minimum, maximum, and mean doses for targets were compared. Data were collected from 40 dogs per anatomic site (head and neck, pelvis, and limbs). The average dose difference between minimum, maximum, and mean doses as calculated on pre- and ceCT plans for the gross tumor volume was less than 1% for all anatomic sites. Similarly, the differences between mean and maximum doses for OAR were less than 1%. The difference in dose distribution between plans made on CTs with and without contrast enhancement was tolerable at all treatment sites. Therefore, although caution would be recommended when planning IM-SBRT for tumors near "reservoirs" for contrast media (such as the heart and urinary bladder), findings supported the use of ceCT with this dose calculation algorithm for both target delineation and IM-SBRT treatment planning. PMID:26242716

  5. Strategies for Online Organ Motion Correction for Intensity-Modulated Radiotherapy of Prostate Cancer: Prostate, Rectum, and Bladder Dose Effects

    SciTech Connect

    Rijkhorst, Erik-Jan; Lakeman, Annemarie; Nijkamp, Jasper; Bois, Josien de; Herk, Marcel van; Lebesque, Joos V.; Sonke, Jan-Jakob

    2009-11-15

    Purpose: To quantify and evaluate the accumulated prostate, rectum, and bladder dose for several strategies including rotational organ motion correction for intensity-modulated radiotherapy (IMRT) of prostate cancer using realistic organ motion data. Methods and Materials: Repeat computed tomography (CT) scans of 19 prostate patients were used. Per patient, two IMRT plans with different uniform margins were created. To quantify prostate and seminal vesicle motion, repeat CT clinical target volumes (CTVs) were matched onto the planning CTV using deformable registration. Four different strategies, from online setup to full motion correction, were simulated. Rotations were corrected for using gantry and collimator angle adjustments. Prostate, rectum, and bladder doses were accumulated for each patient, plan, and strategy. Minimum CTV dose (D{sub min}), rectum equivalent uniform dose (EUD, n = 0.13), and bladder surface receiving >=78 Gy (S78), were calculated. Results: With online CTV translation correction, a 7-mm margin was sufficient (i.e., D{sub min} >= 95% of the prescribed dose for all patients). A 4-mm margin required additional rotational correction. Margin reduction lowered the rectum EUD(n = 0.13) by approx2.6 Gy, and the bladder S78 by approx1.9%. Conclusions: With online correction of both translations and rotations, a 4-mm margin was sufficient for 15 of 19 patients, whereas the remaining four patients had an underdosed CTV volume <1%. Margin reduction combined with online corrections resulted in a similar or lower dose to the rectum and bladder. The more advanced the correction strategy, the better the planned and accumulated dose agreed.

  6. Pitfalls and Challenges to Consider before Setting up a Lung Cancer Intensity-modulated Radiotherapy Service: A Review of the Reported Clinical Experience.

    PubMed

    Shrimali, R K; Mahata, A; Reddy, G D; Franks, K N; Chatterjee, S

    2016-03-01

    Intensity-modulated radiotherapy (IMRT) is being increasingly used for the treatment of non-small cell lung cancer (NSCLC), despite the absence of published randomised controlled trials. Planning studies and retrospective series have shown a decrease in known predictors of lung toxicity (V20 and mean lung dose) and the maximum spinal cord dose. Potential dosimetric advantages, accessibility of technology, a desire to escalate dose or a need to meet normal organ dose constraints are some of the factors recognised as supporting the use of IMRT. However, IMRT may not be appropriate for all patients being treated with radical radiotherapy. Unique problems with using IMRT for NSCLC include organ and tumour motion because of breathing and the potential toxicity from low doses of radiotherapy to larger amounts of lung tissue. Caution should be exercised as there is a paucity of prospective data regarding the efficacy and safety of IMRT in lung cancer when compared with three-dimensional conformal radiotherapy and IMRT data from other cancer sites should not be extrapolated. This review looks at the use of IMRT in NSCLC, addresses the challenges and highlights the potential benefits of using this complex radiotherapy technique.

  7. 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

    SciTech Connect

    Myrehaug, Sten; Chan, Gordon; Craig, Tim; Weinberg, Vivian; Cheng, Chun; Roach, Mack; Cheung, Patrick; Sahgal, Arjun

    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.

  8. Whole breast and excision cavity radiotherapy plan comparison: Conformal radiotherapy with sequential boost versus intensity-modulated radiation therapy with a simultaneously integrated boost

    SciTech Connect

    Small, Katherine; Kelly, Chris; Beldham-Collins, Rachael; Gebski, Val

    2013-03-15

    A comparative study was conducted comparing the difference between (1) conformal radiotherapy (CRT) to the whole breast with sequential boost excision cavity plans and (2) intensity-modulated radiation therapy (IMRT) to the whole breast with simultaneously integrated boost to the excision cavity. The computed tomography (CT) data sets of 25 breast cancer patients were used and the results analysed to determine if either planning method produced superior plans. CT data sets from 25 past breast cancer patients were planned using (1) CRT prescribed to 50 Gy in 25 fractions (Fx) to the whole-breast planning target volume (PTV) and 10 Gy in 5Fx to the excision cavity and (2) IMRT prescribed to 60 Gy in 25Fx, with 60 Gy delivered to the excision cavity PTV and 50 Gy delivered to the whole-breast PTV, treated simultaneously. In total, 50 plans were created, with each plan evaluated by PTV coverage using conformity indices, plan maximum dose, lung dose, and heart maximum dose for patients with left-side lesions. CRT plans delivered the lowest plan maximum doses in 56% of cases (average CRT = 6314.34 cGy, IMRT = 6371.52 cGy). They also delivered the lowest mean lung dose in 68% of cases (average CRT = 1206.64 cGy, IMRT = 1288.37 cGy) and V20 in 88% of cases (average CRT = 20.03%, IMRT = 21.73%) and V30 doses in 92% of cases (average CRT = 16.82%, IMRT = 17.97%). IMRT created more conformal plans, using both conformity index and conformation number, in every instance, and lower heart maximum doses in 78.6% of cases (average CRT = 5295.26 cGy, IMRT = 5209.87 cGy). IMRT plans produced superior dose conformity and shorter treatment duration, but a slightly higher planning maximum and increased lung doses. IMRT plans are also faster to treat on a daily basis, with shorter fractionation.

  9. Poster — Thur Eve — 35: The impact of intensity- and energy-modulated photon radiotherapy (XMRT) optimization on a variety of organ geometries

    SciTech Connect

    McGeachy, P.; Villarreal-Barajas, J. E.; Khan, R.; Zinchenko, Y.

    2014-08-15

    We previously reported on a novel, modulated in both energy and intensity; photon radiotherapy (XMRT) optimization technique. The purpose of this investigation was to test this XMRT optimization against conventional intensity modulated radiotherapy (IMRT) optimization on four different organ test geometries. All geometries mimicked clinically relevant scenarios. Both IMRT and XMRT were based on a linear programming approach where the objective function was the mean dose to healthy organs and organ-specific linear dose-point constraints were used. For IMRT, the beam energy was fixed to 6 MV while XMRT optimized in terms of both 6 and 18 MV beams. All plans consisted of a seven beam coplanar arrangement. All organ geometries were contoured on a 25cm diameter cylindrical water phantom in open source radiotherapy research software known as CERR. Solutions for both IMRT and XMRT were obtained for each geometry using a numerical solver Gurobi. Analyzing the quality of the solutions was done by comparing dose distributions and dose volume histograms calculated using CERR. For all four geometries, IMRT and XMRT solutions were comparable in terms of target coverage. For two of the geometries, IMRT provided an advantage in terms of reduced dose to the healthy structures. XMRT showed improved dose reduction to healthy organs for one geometry and a comparable dose distribution to IMRT for the remaining geometry. The inability to exploit the benefits of using multiple energies may be attributed to limited water phantom diameter and having the majority of the organs in close proximity to the transverse axis.

  10. Consensus Guidelines for Delineation of Clinical Target Volume for Intensity-Modulated Pelvic Radiotherapy in Postoperative Treatment of Endometrial and Cervical Cancer

    SciTech Connect

    Small, William Mell, Loren K.; Anderson, Penny; Creutzberg, Carien; De Los Santos, Jennifer; Gaffney, David; Jhingran, Anuja; Portelance, Lorraine; Schefter, Tracey; Iyer, Revathy; Varia, Mahesh; Winter, Kathryn M.S.; Mundt, Arno J.

    2008-06-01

    Purpose: To develop an atlas of the clinical target volume (CTV) definitions for postoperative radiotherapy of endometrial and cervical cancer to be used for planning pelvic intensity-modulated radiotherapy. Methods and Materials: The Radiation Therapy Oncology Group led an international collaberation of cooperative groups in the development of the atlas. The groups included the Radiation Therapy Oncology Group, Gynecologic Oncology Group, National Cancer Institute of Canada, European Society of Therapeutic Radiology and Oncology, and American College of Radiology Imaging Network. The members of the group were asked by questionnaire to define the areas that were to be included in the CTV and to outline theses areas on individual computed tomography images. The initial formulation of the group began in late 2004 and culminated with a formal consensus conference in June 2005. Results: The committee achieved a consensus CTV definition for postoperative therapy for endometrial and cervical cancer. The CTV should include the common, external, and internal iliac lymph node regions. The upper 3.0 cm of the vagina and paravaginal soft tissue lateral to the vagina should also be included. For patients with cervical cancer, or endometrial cancer with cervical stromal invasion, it is also recommended that the CTV include the presacral lymph node region. Conclusion: This report serves as an international template for the definition of the CTV for postoperative intensity-modulated radiotherapy for endometrial and cervical cancer.

  11. Dosimetric comparison of different multileaf collimator leaves in treatment planning of intensity-modulated radiotherapy for cervical cancer

    SciTech Connect

    Wang, Shichao; Ai, Ping; Xie, Li; Xu, Qingfeng; Bai, Sen; Lu, You; Li, Ping; Chen, Nianyong

    2013-01-01

    To study the effect of multileaf collimator (MLC) leaf widths (standard MLC [sMLC] width of 10 mm and micro-MLC [mMLC] width of 4 mm) on intensity-modulated radiotherapy (IMRT) for cervical cancer. Between January 2010 and August 2010, a retrospective analysis was conducted on 12 patients with cervical cancer. The treatment plans for all patients were generated with the same machine setup parameters and optimization methods in a treatment planning system (TPS) based on 2 commercial Elekta MLC devices. The dose distribution for the planning tumor volume (PTV), the dose sparing for organs at risk (OARs), the monitor units (MUs), and the number of IMRT segments were evaluated. For the delivery efficiency, the MUs were significantly higher in the sMLC-IMRT plan than in the mMLC-IMRT plan (802 ± 56.9 vs 702 ± 56.7; p < 0.05). The number of segments in the plans were 58.75 ± 1.8 and 59 ± 1.04 (p > 0.05). For the planning quality, the conformity index (CI) between the 2 paired IMRT plans with the mMLC and the sMLC did not differ significantly (average: 0.817 ± 0.024 vs 0.810 ± 0.028; p > 0.05). The differences of the homogeneity index (HI) between the 2 paired plans were statistically significant (average: 1.122 ± 0.010 vs 1.132 ± 0.014; p < 0.01). For OARs, the rectum, bladder, small intestine, and bony pelvis were evaluated in terms of V{sub 10}, V{sub 20}, V{sub 30}, and V{sub 40}, percentage of contoured OAR volumes receiving 10, 20, 30, and 40 Gy, respectively, and the mean dose (D{sub mean}) received. The IMRT plans with the mMLC protected the OARs better than the plans with the sMLC. There were significant differences (p < 0.05) in evaluated parameters between the 2 paired IMRT plans, except for V{sub 30} and V{sub 40} of the rectum and V{sub 10}, V{sub 20}, V{sub 40}, and D{sub mean} of the bladder. IMRT plans with the mMLC showed advantages over the plans with the sMLC in dose homogeneity for targets, dose sparing of OARs, and fewer MUs in cervical cancer.

  12. Outcomes of Patients With Head-and-Neck Cancer of Unknown Primary Origin Treated With Intensity-Modulated Radiotherapy

    SciTech Connect

    Shoushtari, Asal; Saylor, Drew; Kerr, Kara-Lynne; Sheng, Ke; Thomas, Christopher; Jameson, Mark; Reibel, James; Shonka, David; Levine, Paul; Read, Paul

    2011-11-01

    Purpose: To analyze survival, failure patterns, and toxicity in patients with head-and-neck carcinoma of unknown primary origin (HNCUP) treated with intensity-modulated radiotherapy (IMRT). Methods and materials: Records from 27 patients with HNCUP treated during the period 2002-2008 with IMRT were reviewed retrospectively. Nodal staging ranged from N1 to N3. The mean preoperative dose to gross or suspected disease, Waldeyer's ring, and uninvolved bilateral cervical nodes was 59.4, 53.5, and 51.0 Gy, respectively. Sixteen patients underwent neck dissection after radiation and 4 patients before radiation. Eight patients with advanced nodal disease (N2b-c, N3) or extracapsular extension received chemotherapy. Results: With a median follow-up of 41.9 months (range, 25.3-93.9 months) for nondeceased patients, the 5-year actuarial overall survival, disease-free survival, and nodal control rates were 70.9%, 85.2%, and 88.5%, respectively. Actuarial disease-free survival rates for N1, N2, and N3 disease were 100%, 94.1%, and 50.0%, respectively, at 5 years. When stratified by nonadvanced (N1, N2a nodal disease without extracapsular spread) vs. advanced nodal disease (N2b, N2c, N3), the 5-year actuarial disease-free survival rate for the nonadvanced nodal disease group was 100%, whereas for the advanced nodal disease group it was significantly lower at 66.7% (p = 0.017). Three nodal recurrences were observed: in 1 patient with bulky N2b disease and 2 in patients with N3 disease. No nodal failures occurred in patients with N1 or N2a disease who received only radiation and surgery. Conclusion: Definitive IMRT to 50-56 Gy followed by neck dissection results in excellent nodal control and overall and disease-free survival, with acceptable toxicity for patients with T0N1 or nonbulky T0N2a disease without extracapsular spread. Patients with extracapsular spread, advanced N2 disease, or N3 disease may benefit from concurrent chemotherapy, targeted therapeutic agents, or

  13. SU-E-T-379: Concave Approximations of Target Volume Dose Metrics for Intensity- Modulated Radiotherapy Treatment Planning

    SciTech Connect

    Xie, Y; Chen, Y; Wickerhauser, M; Deasy, J

    2014-06-01

    Purpose: The widely used treatment plan metric Dx (mimimum dose to the hottest x% by volume of the target volume) is simple to interpret and use, but is computationally poorly behaved (non-convex), this impedes its use in computationally efficient intensity-modulated radiotherapy (IMRT) treatment planning algorithms. We therefore searched for surrogate metrics that are concave, computationally efficient, and accurately correlated to Dx values in IMRT treatment plans. Methods: To find concave surrogates of D95—and more generally, Dx values with variable x values—we tested equations containing one or two generalized equivalent uniform dose (gEUD) functions. Fits were obtained by varying gEUD ‘a’ parameter values, as well as the linear equation coefficients. Fitting was performed using a dataset of dose-volume histograms from 498 de-identified head and neck IMRT treatment plans. Fit characteristics were tested using a crossvalidation process. Reported root-mean-square error values were averaged over the cross-validation shuffles. Results: As expected, the two-gEUD formula provided a superior fit, compared to the single-gEUD formula. The best approximation uses two gEUD terms: 16.25 x gEUD[a=0.45] – 15.30 x gEUD[a=1.75] – 0.69. The average root-mean-square error on repeated (70/30) cross validation was 0.94 Gy. In addition, a formula was found that reasonably approximates Dx for x between 80% and 96%. Conclusion: A simple concave function using two gEUD terms was found that correlates well with PTV D95s for these head and neck treatment plans. More generally, a formula was found that represents well the Dx for x values from 80% to 96%, thus providing a computationally efficient formula for use in treatment planning optimization. The formula may need to be adjusted for other institutions with different treatment planning protocols. We conclude that the strategy of replacing Dx values with gEUD-based formulas is promising.

  14. Protocol for the isotoxic intensity modulated radiotherapy (IMRT) in stage III non-small cell lung cancer (NSCLC): a feasibility study

    PubMed Central

    Haslett, Kate; Franks, Kevin; Harden, Susan; Hatton, Matthew; McDonald, Fiona; Ashcroft, Linda; Falk, Sally; Groom, Nicki; Harris, Catherine; McCloskey, Paula; Whitehurst, Philip; Bayman, Neil

    2016-01-01

    Introduction The majority of stage III patients with non-small cell lung cancer (NSCLC) are unsuitable for concurrent chemoradiotherapy, the non-surgical gold standard of care. As the alternative treatment options of sequential chemoradiotherapy and radiotherapy alone are associated with high local failure rates, various intensification strategies have been employed. There is evidence to suggest that altered fractionation using hyperfractionation, acceleration, dose escalation, and individualisation may be of benefit. The MAASTRO group have pioneered the concept of ‘isotoxic’ radiotherapy allowing for individualised dose escalation using hyperfractionated accelerated radiotherapy based on predefined normal tissue constraints. This study aims to evaluate whether delivering isotoxic radiotherapy using intensity modulated radiotherapy (IMRT) is achievable. Methods and analysis Isotoxic IMRT is a multicentre feasibility study. From June 2014, a total of 35 patients from 7 UK centres, with a proven histological or cytological diagnosis of inoperable NSCLC, unsuitable for concurrent chemoradiotherapy will be recruited. A minimum of 2 cycles of induction chemotherapy is mandated before starting isotoxic radiotherapy. The dose of radiation will be increased until one or more of the organs at risk tolerance or the maximum dose of 79.2 Gy is reached. The primary end point is feasibility, with accrual rates, local control and overall survival our secondary end points. Patients will be followed up for 5 years. Ethics and dissemination The study has received ethical approval (REC reference: 13/NW/0480) from the National Research Ethics Service (NRES) Committee North West—Greater Manchester South. The trial is conducted in accordance with the Declaration of Helsinki and Good Clinical Practice (GCP). The trial results will be published in a peer-reviewed journal and presented internationally. Trial registration number NCT01836692; Pre-results. PMID:27084277

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

    SciTech Connect

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

    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.

  16. Intensity modulated radiotherapy and 3D conformal radiotherapy for whole breast irradiation: a comparative dosimetric study and introduction of a novel qualitative index for plan evaluation, the normal tissue index

    PubMed Central

    Yim, Jackie; Suttie, Clare; Bromley, Regina; Morgia, Marita; Lamoury, Gillian

    2015-01-01

    Introduction We report on a retrospective dosimetric study, comparing 3D conformal radiotherapy (3DCRT) and hybrid intensity modulated radiotherapy (hIMRT). We evaluated plans based on their planning target volume coverage, dose homogeneity, dose to organs at risk (OARs) and exposure of normal tissue to radiation. The Homogeneity Index (HI) was used to assess the dose homogeneity in the target region, and we describe a new index, the normal tissue index (NTI), to assess the dose in the normal tissue inside the tangent treatment portal. Methods Plans were generated for 25 early-stage breast cancer patients, using a hIMRT technique. These were compared with the 3DCRT plans of the treatment previously received by the patients. Plan quality was evaluated using the HI, NTI and dose to OARs. Results The hIMRT technique was significantly more homogenous than the 3DCRT technique, while maintaining target coverage. The hIMRT technique was also superior at minimising the amount of tissue receiving D105% and above (P < 0.0001). The ipsilateral lung and contralateral breast maximum were significantly lower in the hIMRT plans (P < 0.05 and P < 0.005), but the 3DCRT technique achieved a lower mean heart dose in left-sided breast cancer patients (P < 0.05). Conclusion Hybrid intensity modulated radiotherapy plans achieved improved dose homogeneity compared to the 3DCRT plans and superior outcome with regard to dose to normal tissues. We propose that the addition of both HI and NTI in evaluating the quality of intensity modulated radiotherapy (IMRT) breast plans provides clinically relevant comparators which more accurately reflect the new paradigm of treatment goals and outcomes in the era of breast IMRT. PMID:26451240

  17. Intensity modulated radiotherapy and 3D conformal radiotherapy for whole breast irradiation: a comparative dosimetric study and introduction of a novel qualitative index for plan evaluation, the normal tissue index

    SciTech Connect

    Yim, Jackie; Suttie, Clare; Bromley, Regina; Morgia, Marita; Lamoury, Gillian

    2015-09-15

    We report on a retrospective dosimetric study, comparing 3D conformal radiotherapy (3DCRT) and hybrid intensity modulated radiotherapy (hIMRT). We evaluated plans based on their planning target volume coverage, dose homogeneity, dose to organs at risk (OARs) and exposure of normal tissue to radiation. The Homogeneity Index (HI) was used to assess the dose homogeneity in the target region, and we describe a new index, the normal tissue index (NTI), to assess the dose in the normal tissue inside the tangent treatment portal. Plans were generated for 25 early-stage breast cancer patients, using a hIMRT technique. These were compared with the 3DCRT plans of the treatment previously received by the patients. Plan quality was evaluated using the HI, NTI and dose to OARs. The hIMRT technique was significantly more homogenous than the 3DCRT technique, while maintaining target coverage. The hIMRT technique was also superior at minimising the amount of tissue receiving D{sub 105%} and above (P < 0.0001). The ipsilateral lung and contralateral breast maximum were significantly lower in the hIMRT plans (P < 0.05 and P < 0.005), but the 3DCRT technique achieved a lower mean heart dose in left-sided breast cancer patients (P < 0.05). Hybrid intensity modulated radiotherapy plans achieved improved dose homogeneity compared to the 3DCRT plans and superior outcome with regard to dose to normal tissues. We propose that the addition of both HI and NTI in evaluating the quality of intensity modulated radiotherapy (IMRT) breast plans provides clinically relevant comparators which more accurately reflect the new paradigm of treatment goals and outcomes in the era of breast IMRT.

  18. Intensity-Modulated Radiotherapy as Primary Therapy for Prostate Cancer: Report on Acute Toxicity After Dose Escalation With Simultaneous Integrated Boost to Intraprostatic Lesion

    SciTech Connect

    Fonteyne, Valerie Villeirs, Geert; Speleers, Bruno; Neve, Wilfried de; Wagter, Carlos de; Lumen, Nicolas; Meerleer, Gert de

    2008-11-01

    Purpose: To report on the acute toxicity of a third escalation level using intensity-modulated radiotherapy for prostate cancer (PCa) and the acute toxicity resulting from delivery of a simultaneous integrated boost (SIB) to an intraprostatic lesion (IPL) detected on magnetic resonance imaging (MRI), with or without spectroscopy. Methods and Materials: Between January 2002 and March 2007, we treated 230 patients with intensity-modulated radiotherapy to a third escalation level as primary therapy for prostate cancer. If an IPL (defined by MRI or MRI plus spectroscopy) was present, a SIB was delivered to the IPL. To report on acute toxicity, patients were seen weekly during treatment and 1 and 3 months after treatment. Toxicity was scored using the Radiation Therapy Oncology Group toxicity scale, supplemented by an in-house-developed scoring system. Results: The median dose to the planning target volume was 78 Gy. An IPL was found in 118 patients. The median dose to the MRI-detected IPL and MRI plus spectroscopy-detected IPL was 81 Gy and 82 Gy, respectively. No Grade 3 or 4 acute gastrointestinal toxicity developed. Grade 2 acute gastrointestinal toxicity was present in 26 patients (11%). Grade 3 genitourinary toxicity was present in 15 patients (7%), and 95 patients developed Grade 2 acute genitourinary toxicity (41%). No statistically significant increase was found in Grade 2-3 acute gastrointestinal or genitourinary toxicity after a SIB to an IPL. Conclusion: The results of our study have shown that treatment-induced acute toxicity remains low when intensity-modulated radiotherapy to 80 Gy as primary therapy for prostate cancer is used. In addition, a SIB to an IPL did not increase the severity or incidence of acute toxicity.

  19. SU-E-T-394: The Use of Jaw Tracking in Intensity Modulated and Volumetric Modulated Arc Radiotherapy for Spine Stereotactic Radiosurgery

    SciTech Connect

    Chin, K; Wen, N; Huang, Y; Kim, J; Zhao, B; Siddiqui, S; Chetty, I; Ryu, S

    2014-06-01

    Purpose: To evaluate the potential advantages of jaw tracking for intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) in spine radiosurgery. Methods: VMAT and IMRT plans were retrospectively generated for ten patients. Six plans for each patient were created in the Eclipse treatment planning system for a Varian Truebeam equipped with a Millennium 120 MLC. Plans were created to study IMRT and VMAT plans with and without jaw tracking, as well as IMRT plans of different flattening filter free (FFF) energies. Plans were prescribed to the 90% isodose line to 16 or 18 Gy in one fraction to cover 95% of the target. Planning target volume (PTV) coverage, conformity index (CI), dose to spinal cord, distance to fall off from the 90% to 50% isodose line (DTF), as well as delivery time were evaluated. Ion chamber and film measurements were performed to verify calculated and measured dose distributions. Results: Jaw tracking decreased the spinal cord dose for both IMRT and VMAT plans, but a larger decrease was seen with the IMRT plans (p=0.004 vs p=0.04). The average D10% for the spinal cord was least for the 6MV FFF IMRT plan with jaw tracking and was greatest for the 10MV FFF plan without jaw tracking. Treatment times between IMRT and VMAT plans with or without jaw tracking were not significantly different. Measured plans showed greater than 98.5% agreement for planar dose gamma analysis (3%/2 mm) and less than 2.5% for point dose analysis compared to calculated plans. Conclusion: Jaw tracking can be used to help decrease spinal cord dose without any change in treatment delivery or calculation accuracy. Lower dose to the spinal cord was achieved using 6 MV beams compared to 10 MV beams, though 10 MV may be justified in some cases to decrease skin dose.

  20. Daily Image Guidance With Cone-Beam Computed Tomography for Head-and-Neck Cancer Intensity-Modulated Radiotherapy: A Prospective Study

    SciTech Connect

    Den, Robert B.; Doemer, Anthony; Kubicek, Greg; Bednarz, Greg; Galvin, James M.; Keane, William M.; Xiao Ying; Machtay, Mitchell

    2010-04-15

    Purpose: To report on a prospective clinical trial of the use of daily kilovoltage cone-beam computed tomography (CBCT) to evaluate the interfraction and residual error motion of patients undergoing intensity-modulated radiotherapy for head-and-neck cancer. Methods and Materials: Patients were treated with intensity-modulated radiotherapy with an Elekta linear accelerator using a mounted CBCT scanner. CBCT was performed before every treatment, and translational (but not rotational) corrections were performed. At least once per week, a CBCT scan was obtained after intensity-modulated radiotherapy. Variations were measured in the medial-lateral, superoinferior, and anteroposterior dimensions, as well as in the rotation around these axes. Results: A total of 28 consecutive patients (1,013 CBCT scans) were studied. The average interfraction shift was 1.4 +- 1.4, 1.7 +- 1.9, and 1.8 +- 2.1 mm in the medial-lateral, superoinferior, and anteroposterior dimensions, respectively. The corresponding average residual error shifts were 0.7 +- 0.8, 0.9 +- 0.9, and 0.9 +- 0.9 mm. These data indicate that in the absence of daily CBCT image-guided radiotherapy, a clinical target volume to planning target volume margin of 3.9, 4.1, and 4.9 mm is needed in the medial-lateral, superoinferior, and anteroposterior dimensions, respectively. With daily CBCT, corresponding margins of 1.6, 2.5, and 1.9 mm should be acceptable. Subgroup analyses showed that larynx cancers and/or intratreatment weight loss indicate a need for slightly larger clinical target volume to planning target volume margins. Conclusion: The results of our study have shown that image-guided radiotherapy using CBCT for head-and-neck cancer is effective. These data suggest it allows a reduction in the clinical target volume to planning target volume margins by about 50%, which could facilitate future studies of dose escalation and/or improved toxicity reduction. Caution is particularly warranted for cases in which the

  1. Health-Related Quality of Life in Patients With Locally Advanced Prostate Cancer After 76 Gy Intensity-Modulated Radiotherapy vs. 70 Gy Conformal Radiotherapy in a Prospective and Longitudinal Study

    SciTech Connect

    Lips, Irene Dehnad, Human; Kruger, Arto Boeken; Moorselaar, Jeroen van; Heide, Uulke van; Battermann, Jan; Vulpen, Marco van

    2007-11-01

    Purpose: To compare quality of life (QoL) after 70 Gy conformal radiotherapy with QoL after 76 Gy intensity-modulated radiotherapy (IMRT) in patients with locally advanced prostate carcinoma. Methods and Materials: Seventy-eight patients with locally advanced prostate cancer were treated with 70 Gy three-field conformal radiotherapy, and 92 patients received 76 Gy IMRT with fiducial markers for position verification. Quality of life was measured by RAND-36, the European Organization for Research and Treatment of Cancer core questionnaire (EORTC QLQ-C30(+3)), and the prostate-specific EORTC QLQ-PR25, before radiotherapy (baseline) and 1 month and 6 months after treatment. Quality of life changes in time (baseline vs. 1 month and baseline vs. 6 months) of {>=}10 points were considered clinically relevant. Results: Differences between the treatment groups for QoL changes over time occurred in several QoL domains. The 76-Gy group revealed no significant deterioration in QoL compared with the 70-Gy group. The IMRT 76-Gy group even demonstrated a significantly better change in QoL from baseline to 1 month in several domains. The conformal 70-Gy group revealed temporary deterioration in pain, role functioning, and urinary symptoms; for the IMRT 76-Gy group a better QoL in terms of change in health existed after 1 month, which persisted after 6 months. For both treatment groups temporary deterioration in physical role restriction occurred after 1 month, and an improvement in emotional role restriction occurred after 6 months. Sexual activity was reduced after treatment for both groups and remained decreased after 6 months. Conclusions: Intensity-modulated radiotherapy and accurate position verification seem to provide a possibility to increase the radiation dose for prostate cancer without deterioration in QoL.

  2. Inverse planned stereotactic intensity modulated radiotherapy (IMRT) in the palliative treatment of malignant mesothelioma of the pleura: the Heidelberg experience.

    PubMed

    Münter, Marc W; Thieke, Christian; Christian, Thieke; Nikoghosyan, Anna; Anna, Nikoghosyan; Nill, Simeon; Simeon, Nill; Debus, Jürgen; Jürgen, Debus

    2005-07-01

    Intensity modulated radiation therapy (IMRT) is a new promising treatment technique, which allows a more conformal application of the dose to the tumor volume, as compared to conventional radio-oncological approaches, while protecting the surrounding normal tissue more accurately. This manuscript presents the final results of IMRT in the treatment of unresectable pleural mesothelioma in Heidelberg.

  3. Hypothyroidism as a Consequence of Intensity-Modulated Radiotherapy With Concurrent Taxane-Based Chemotherapy for Locally Advanced Head-and-Neck Cancer

    SciTech Connect

    Diaz, Roberto; Jaboin, Jerry J.; Morales-Paliza, Manuel; Koehler, Elizabeth; Phillips, John G.; Stinson, Scott; Gilbert, Jill; Chung, Christine H.; Murphy, Barbara A.; Murphy, Patrick B.; Shyr, Yu; Cmelak, Anthony J.

    2010-06-01

    Purpose: To conduct a retrospective review of 168 consecutively treated locally advanced head-and-neck cancer (LAHNC) patients treated with intensity-modulated radiotherapy (IMRT)/chemotherapy, to determine the rate and risk factors for developing hypothyroidism. Methods and Materials: Intensity-modulated radiotherapy was delivered in 33 daily fractions to 69.3 Gy to gross disease and 56.1 Gy to clinically normal cervical nodes. Dose-volume histograms (DVHs) of IMRT plans were used to determine radiation dose to thyroid and were compared with DVHs using conventional three-dimensional radiotherapy (3D-RT) in 10 of these same patients randomly selected for replanning and with DVHs of 16 patients in whom the thyroid was intentionally avoided during IMRT. Weekly paclitaxel (30 mg/m{sup 2}) and carboplatin area under the curve-1 were given concurrently with IMRT. Results: Sixty-one of 128 evaluable patients (47.7%) developed hypothyroidism after a median of 1.08 years after IMRT (range, 2.4 months to 3.9 years). Age and volume of irradiated thyroid were associated with hypothyroidism development after IMRT. Compared with 3D-RT, IMRT with no thyroid dose constraints resulted in significantly higher minimum, maximum, and median dose (p < 0.0001) and percentage thyroid volume receiving 10, 20, and 60 Gy (p < 0.05). Compared with 3D-RT, IMRT with thyroid dose constraints resulted in lower median dose and percentage thyroid volume receiving 30, 40, and 50 Gy (p < 0.005) but higher minimum and maximum dose (p < 0.005). Conclusions: If not protected, IMRT for LAHNC can result in higher radiation to the thyroid than with conventional 3D-RT. Techniques to reduce dose and volume of radiation to thyroid tissue with IMRT are achievable and recommended.

  4. Long-term cancer-related fatigue outcomes in patients with locally advanced prostate cancer after intensity-modulated radiotherapy combined with hormonal therapy

    PubMed Central

    Luo, Hua-Chun; Lei, Yong; Cheng, Hui-Hua; Fu, Zhi-Chao; Liao, Shao-Guang; Feng, Jing; Yin, Qin; Chen, Qun-Hua; Lin, Gui-Shan; Zhu, Jin-Feng; Xu, Jian-Feng; Wang, Dian

    2016-01-01

    Abstract The aim of our study was to investigate the relationship between cancer-related fatigue and clinical parameters, and the effect factors of fatigue for the prostate cancer patients. Long-term follow-up is performed using the Fatigue Symptom Inventory before treatment (A), at the end of intensity-modulated radiotherapy (B), and 3 months (C), 12 months (D), 24 months (E), 36 months (F), and 48 months (G) after the end of intensity-modulated radiotherapy. Three dimensions of fatigue are assessed during follow-up: severity, perceived interference with quality of life, and duration in the past week. In all, 97 patients with locally advanced prostate cancer were enrolled in the study. Median follow-up time was 43.9 months. The fatigue index was significantly higher in the prostate-specific antigen >20 ng/mL, Gleason score >8, the Eastern Cooperative Oncology Group scores, and the higher education. The most severe fatigue occurred at time points B and C. The score for duration of fatigue fluctuated across the time points, with significantly increased scores at time points D, E, and F. In conclusion, we show that cancer-related fatigue is the important symptom which affects the quality of life for the prostate cancer patients. For patients with locally advanced prostate cancer with a high Eastern Cooperative Oncology Group score, a Gleason score of >8 points, prostate-specific antigen levels of >20 ng/mL, and high education, attention should be paid to the interference of fatigue with quality of life, especially general level of activity, ability to concentrate, and mood, after radiotherapy combined with hormonal therapy. PMID:27336890

  5. Coplanar intensity-modulated radiotherapy class solution for patients with prostate cancer with bilateral hip prostheses with and without nodal involvement

    SciTech Connect

    Lee, Young K.; McVey, Gerard P.; South, Chris P.; Dearnaley, David P.

    2013-07-01

    Dose distributions for prostate radiotherapy are difficult to predict in patients with bilateral hip prostheses in situ, due to image distortions and difficulty in dose calculation. The feasibility of delivering curative doses to prostate using intensity-modulated radiotherapy (IMRT) in patients with bilateral hip prostheses was evaluated. Planning target volumes for prostate only (PTV1) and pelvic nodes (PTV2) were generated from data on 5 patients. PTV1 and PTV2 dose prescriptions were 70 Gy and 60 Gy, respectively, in 35 fractions, and an additional nodal boost of 65 Gy was added for 1 plan. Rectum, bladder, and bowel were also delineated. Beam angles and segments were chosen to best avoid entering through the prostheses. Dose-volume data were assessed with respect to clinical objectives. The plans achieved the required prescription doses to the PTVs. Five-field IMRT plans were adequate for patients with relatively small prostheses (head volumes<60 cm{sup 3}) but 7-field plans were required for patients with larger prostheses. Bowel and bladder doses were clinically acceptable for all patients. Rectal doses were deemed clinically acceptable, although the V{sub 50} {sub Gy} objective was not met for 4/5 patients. We describe an IMRT solution for patients with bilateral hip prostheses of varying size and shape, requiring either localized or whole pelvic radiotherapy for prostate cancer.

  6. Whole Abdominopelvic Radiotherapy Using Intensity-Modulated Arc Therapy in the Palliative Treatment of Chemotherapy-Resistant Ovarian Cancer With Bulky Peritoneal Disease: A Single-Institution Experience

    SciTech Connect

    De Meerleer, Gert; Vandecasteele, Katrien; Ost, Piet; Delrue, Louke; Denys, Hannelore; Makar, Amin; Speleers, Bruno; Van Belle, Simon; Van den Broecke, Rudy; Fonteyne, Valerie; De Neve, Wilfried

    2011-03-01

    Purpose: To retrospectively review our experience with whole abdominopelvic radiotherapy (WAPRT) using intensity-modulated arc therapy in the palliative treatment of chemotherapy-resistant ovarian cancer with bulky peritoneal disease. Methods and Materials: Between April 2002 and April 2008, 13 patients were treated with WAPRT using intensity-modulated arc therapy. We prescribed a dose of 33 Gy to be delivered in 22 fractions of 1.5 Gy to the abdomen and pelvis. All patients had International Federation of Gynecology and Obstetrics Stage III or IV ovarian cancer at the initial diagnosis. At referral, the median age was 61 years, and the patients had been heavily pretreated with surgery and chemotherapy. All patients had symptoms from their disease, including gastrointestinal obstruction or subobstruction in 6, minor gastrointestinal symptoms in 2, pain in 4, ascites in 1, and vaginal bleeding in 2. A complete symptom or biochemical response required complete resolution of the patient's symptoms or cancer antigen-125 level. A partial response required {>=}50% resolution of these parameters. The actuarial survival was calculated from the start of radiotherapy. Results: The median overall survival was 21 weeks, with a 6-month overall survival rate of 45%. The 9 patients who completed treatment obtained a complete symptom response, except for ascites (partial response). The median and mean response duration (all symptoms grouped) was 24 and 37 weeks, respectively. Of the 6 patients presenting with obstruction or subobstruction, 4 obtained a complete symptom response (median duration, 16 weeks). Conclusion: WAPRT delivered using intensity-modulated arc therapy offers important palliation in the case of peritoneal metastatic ovarian cancer. WAPRT resolved intestinal obstruction for a substantial period.

  7. Volumetric-modulated arc therapy vs conventional fixed-field intensity-modulated radiotherapy in a whole-ventricular irradiation: A planning comparison study

    SciTech Connect

    Sakanaka, Katsuyuki; Mizowaki, Takashi; Sato, Sayaka; Ogura, Kengo; Hiraoka, Masahiro

    2013-07-01

    This study evaluated the dosimetric difference between volumetric-modulated arc therapy (VMAT) and conventional fixed-field intensity-modulated radiotherapy (cIMRT) in whole-ventricular irradiation. Computed tomography simulation data for 13 patients were acquired to create plans for VMAT and cIMRT. In both plans, the same median dose (100% = 24 Gy) was prescribed to the planning target volume (PTV), which comprised a tumor bed and whole ventricles. During optimization, doses to the normal brain and body were reduced, provided that the dose constraints of the target coverage were satisfied. The dose-volume indices of the PTV, normal brain, and body as well as monitor units were compared between the 2 techniques by using paired t-tests. The results showed no significant difference in the homogeneity index (0.064 vs 0.065; p = 0.824) of the PTV and conformation number (0.78 vs 0.77; p = 0.065) between the 2 techniques. In the normal brain and body, the dose-volume indices showed no significant difference between the 2 techniques, except for an increase in the volume receiving a low dose in VMAT; the absolute volume of the normal brain and body receiving 1 Gy of radiation significantly increased in VMAT by 1.6% and 8.3%, respectively, compared with that in cIMRT (1044 vs 1028 mL for the normal brain and 3079.2 vs 2823.3 mL for the body; p<0.001). The number of monitor units to deliver a 2.0-Gy fraction was significantly reduced in VMAT compared with that in cIMRT (354 vs 873, respectively; p<0.001). In conclusion, VMAT delivers IMRT to complex target volumes such as whole ventricles with fewer monitor units, while maintaining target coverage and conformal isodose distribution comparable to cIMRT; however, in addition to those characteristics, the fact that the volume of the normal brain and body receiving a low dose would increase in VMAT should be considered.

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

    PubMed Central

    Jeong, Songmi; Yoo, Eun Jung; Kim, Ji Yoon; Han, Chi Wha; Kim, Ki Jun

    2013-01-01

    Purpose 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. Materials and Methods 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. Results 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. Conclusion 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. PMID:24501708

  9. 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

    SciTech Connect

    Qiao, L; Deng, G; Xie, J; Cheng, J; Liang, N; Zhang, J; Zhang, J; Luo, H

    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.

  10. Phase I-II Trial of Concurrent Capecitabine and Oxaliplatin With Preoperative Intensity-Modulated Radiotherapy in Patients With Locally Advanced Rectal Cancer

    SciTech Connect

    Aristu, Jose Javier Arbea, Leire; Rodriguez, Javier; Hernandez-Lizoain, Jose Luis; Sola, Jesus Javier; Moreno, Marta M.D.; Azcona, Juan Diego; Diaz-Gonzalez, Juan Antonio; Garcia-Foncillas, Jesus Miguel; Martinez-Monge, Rafael

    2008-07-01

    Purpose: To identify the maximal tolerated dose level of preoperative intensity-modulated radiotherapy combined with capecitabine and oxaliplatin and to evaluate the efficacy. Patients and Methods: Patients with rectal T3-T4 and/or N0-N+ rectal cancer received capecitabine 825 mg/m{sup 2} twice daily Monday through Friday and oxaliplatin 60 mg/m{sup 2} intravenously on Days 1, 8, and 15, concurrently with intensity-modulated radiotherapy. The radiation dose was increased in 5.0-Gy steps in cohorts of 3 patients starting from 37.5 Gy in 15 fractions (dose level [DL] 1). DL2 and DL3 were designed to reach 42.5 Gy in 17 fractions and 47.5 Gy in 19 fractions, respectively. Results: No dose-limiting toxicity was observed at DL1 or DL2. Of the 3 patients treated at DL3, 1 presented with Grade 3 diarrhea, which was considered a dose-limiting toxicity, and 3 additional patients were added. Of the 6 patients treated at DL3, no new dose-limiting toxicities were observed, and DL3 was identified as the recommended dose in this study. Eight additional patients were treated at 47.5 Gy. Grade 2 proctitis was the most frequent adverse event (40%); Grade 3 diarrhea occurred in 2 patients (10%). All patients underwent surgery, and 17 patients (85%) underwent R0 resection. Four patients (20%) presented with a histologic response of Grade 4, 11 (55%) with Grade 3+, 2 (15%) with Grade 3, and 2 patients (10%) with Grade 2. Conclusion: The maximal tolerated dose in this study was 47.5 Gy. The high rates of pathologic response of Grade 3+ and 4 must be confirmed through the accrual of new patients in the Phase II study.

  11. Assessment of Planning Target Volume Margins for Intensity-Modulated Radiotherapy of the Prostate Gland: Role of Daily Inter- and Intrafraction Motion

    SciTech Connect

    Tanyi, James A.; He, Tongming; Summers, Paige A.; Mburu, Ruth G.; Kato, Catherine M.; Rhodes, Stephen M.; Hung, Arthur Y.; Fuss, Martin

    2010-12-01

    Purpose: To determine planning target volume margins for prostate intensity-modulated radiotherapy based on inter- and intrafraction motion using four daily localization techniques: three-point skin mark alignment, volumetric imaging with bony landmark registration, volumetric imaging with implanted fiducial marker registration, and implanted electromagnetic transponders (beacons) detection. Methods and Materials: Fourteen patients who underwent definitive intensity-modulated radiotherapy for prostate cancer formed the basis of this study. Each patient was implanted with three electromagnetic transponders and underwent a course of 39 treatment fractions. Daily localization was based on three-point skin mark alignment followed by transponder detection and patient repositioning. Transponder positioning was verified by volumetric imaging with cone-beam computed tomography of the pelvis. Relative motion between the prostate gland and bony anatomy was quantified by offline analyses of daily cone-beam computed tomography. Intratreatment organ motion was monitored continuously by the Calypso (registered) System for quantification of intrafraction setup error. Results: As expected, setup error (that is, inter- plus intrafraction motion, unless otherwise stated) was largest with skin mark alignment, requiring margins of 7.5 mm, 11.4 mm, and 16.3 mm, in the lateral (LR), longitudinal (SI), and vertical (AP) directions, respectively. Margin requirements accounting for intrafraction motion were smallest for transponder detection localization techniques, requiring margins of 1.4 mm (LR), 2.6 mm (SI), and 2.3 mm (AP). Bony anatomy alignment required 2.1 mm (LR), 9.4 mm (SI), and 10.5 mm (AP), whereas image-guided marker alignment required 2.8 mm (LR), 3.7 mm (SI), and 3.2 mm (AP). No marker migration was observed in the cohort. Conclusion: Clinically feasible, rapid, and reliable tools such as the electromagnetic transponder detection system for pretreatment target localization

  12. Treatment Plan Technique and Quality for Single-Isocenter Stereotactic Ablative Radiotherapy of Multiple Lung Lesions with Volumetric-Modulated Arc Therapy or Intensity-Modulated Radiosurgery

    PubMed Central

    Quan, Kimmen; Xu, Karen M.; Lalonde, Ron; Horne, Zachary D.; Bernard, Mark E.; McCoy, Chuck; Clump, David A.; Burton, Steven A.; Heron, Dwight E.

    2015-01-01

    The aim of this study is to provide a practical approach to the planning technique and evaluation of plan quality for the multi-lesion, single-isocenter stereotactic ablative radiotherapy (SABR) of the lung. Eleven patients with two or more lung lesions underwent single-isocenter volumetric-modulated arc therapy (VMAT) radiosurgery or IMRS. All plans were normalized to the target maximum dose. For each plan, all targets were treated to the same dose. Plan conformity and dose gradient were maximized with dose-control tuning structures surrounding targets. For comparison, multi-isocenter plans were retrospectively created for four patients. Conformity index (CI), homogeneity index (HI), gradient index (GI), and gradient distance (GD) were calculated for each plan. V5, V10, and V20 of the lung and organs at risk (OARs) were collected. Treatment time and total monitor units (MUs) were also recorded. One patient had four lesions and the remainder had two lesions. Six patients received VMAT and five patients received intensity-modulated radiosurgery (IMRS). For those treated with VMAT, two patients received 3-arc VMAT and four received 2-arc VMAT. For those treated with IMRS, two patients were treated with 10 and 11 beams, respectively, and the rest received 12 beams. Prescription doses ranged from 30 to 54 Gy in three to five fractions. The median prescribed isodose line was 84% (range: 80–86%). The median maximum dose was 57.1 Gy (range: 35.7–65.1 Gy). The mean combined PTV was 49.57 cm3 (range: 14.90–87.38 cm3). For single-isocenter plans, the median CI was 1.15 (range: 0.97–1.53). The median HI was 1.19 (range: 1.16–1.28). The median GI was 4.60 (range: 4.16–7.37). The median maximum radiation dose (Dmax) to total lung was 55.6 Gy (range: 35.7–62.0 Gy). The median mean radiation dose to the lung (Dmean) was 4.2 Gy (range: 1.1–9.3 Gy). The median lung V5 was 18.7% (range: 3.8–41.3%). There was no significant difference in CI, HI, GI

  13. Investigating the Temporal Effects of Respiratory-Gated and Intensity-Modulated Radiotherapy Treatment Delivery on In Vitro Survival: An Experimental and Theoretical Study

    SciTech Connect

    Keall, Paul J. Chang, Michael; Benedict, Stanley; Thames, Howard; Vedam, S. Sastry; Lin, Peck-Sun

    2008-08-01

    Purpose: To experimentally and theoretically investigate the temporal effects of respiratory-gated and intensity-modulated radiotherapy (IMRT) treatment delivery on in vitro survival. Methods and Materials: Experiments were designed to isolate the effects of periodic irradiation (gating), partial tumor irradiation (IMRT), and extended treatment time (gating and IMRT). V79 Chinese hamster lung fibroblast cells were irradiated to 2 Gy with four delivery methods and a clonogenic assay performed. Theoretical incomplete repair model calculations were performed using the incomplete repair model. Results: Treatment times ranged from 1.67 min (conformal radiotherapy, CRT) to 15 min (gated IMRT). Survival fraction calculations ranged from 68.2% for CRT to 68.7% for gated IMRT. For the same treatment time (5 min), gated delivery alone and IMRT delivery alone both had a calculated survival fraction of 68.3%. The experimental values ranged from 65.7% {+-} 1.0% to 67.3% {+-} 1.3%, indicating no significant difference between the experimental observations and theoretical calculations. Conclusion: The theoretical results predicted that of the three temporal effects of radiation delivery caused by gating and IMRT, extended treatment time was the dominant effect. Care should be taken clinically to ensure that the use of gated IMRT does not significantly increase treatment times, by evaluating appropriate respiratory gating duty cycles and IMRT delivery complexity.

  14. Quantification of Trade-Off Between Parotid Gland Sparing and Planning Target Volume Underdosages in Clinically Node-Negative Head-and-Neck Intensity-Modulated Radiotherapy

    SciTech Connect

    Kruijf, Wilhelmus de . E-mail: kruijf.de.w@bvi.nl; Heijmen, Ben; Levendag, Peter C.

    2007-05-01

    Purpose: To quantify the trade-off between parotid gland sparing and planning target volume (PTV) underdosages for head-and-neck intensity-modulated radiotherapy. Methods and Materials: A planning study was performed for 4 patients with either soft palate or tonsil tumors treated with external radiotherapy up to 46 Gy. The trade-off between underdosages in the PTV and sparing of the parotid glands was investigated by systematically varying the optimization objectives for the inverse planning. A new way of presenting dose-volume information allows easy detection of small PTV subvolumes with underdosages that cannot be assessed in conventional cumulative dose-volume histograms. A simple radiobiological model to estimate the control probability for an electively irradiated neck level was developed. Results: The average dose to the parotid glands can decrease by >10 Gy by allowing the PTV to be underdosed in such a way that the radiobiological model predicts a decrease in subclinical disease control probability of (typically) 1% to a few percent. Conclusion: The trade-off between parotid gland sparing and underdosages in the PTV has been quantified by the use of an alternative method to present dose-volume information and by the use of a radiobiological model to predict subclinical disease control probability.

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

    SciTech Connect

    Ma, C; Yin, Y

    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.

  16. Phase I Trial of Preoperative Hypofractionated Intensity-Modulated Radiotherapy with Incorporated Boost and Oral Capecitabine in Locally Advanced Rectal Cancer

    SciTech Connect

    Freedman, Gary M. . E-mail: G_Freedman@FCCC.edu; Meropol, Neal J.; Sigurdson, Elin R.; Hoffman, John; Callahan, Elaine; Price, Robert; Cheng, Jonathan; Cohen, Steve; Lewis, Nancy; Watkins-Bruner, Deborah; Rogatko, Andre; Konski, Andre

    2007-04-01

    Purpose: To determine the safety and efficacy of preoperative hypofractionated radiotherapy using intensity-modulated radiotherapy (IMRT) and an incorporated boost with concurrent capecitabine in patients with locally advanced rectal cancer. Methods and Materials: The eligibility criteria included adenocarcinoma of the rectum, T3-T4 and/or N1-N2 disease, performance status 0 or 1, and age {>=}18 years. Photon IMRT and an incorporated boost were used to treat the whole pelvis to 45 Gy and the gross tumor volume plus 2 cm to 55 Gy in 25 treatments within 5 weeks. The study was designed to escalate the dose to the gross tumor volume in 5-Gy increments in 3-patient cohorts. Capecitabine was given orally 825 mg/m{sup 2} twice daily for 7 days each week during RT. The primary endpoint was the maximal tolerated radiation dose, and the secondary endpoints were the pathologic response and quality of life. Results: Eight patients completed RT at the initial dose level of 55 Gy. The study was discontinued because of toxicity-six Grade 3 toxicities occurred in 3 (38%) of 8 patients. All patients went on to definitive surgical resection, and no patient had a pathologically complete response. Conclusion: This regimen, using hypofractionated RT with an incorporated boost, had unacceptable toxicity despite using standard doses of capecitabine and IMRT. Additional research is needed to determine whether IMRT is able to reduce the side effects during and after pelvic RT with conventional dose fractionation.

  17. [Intensity-modulated radiotherapy of head and neck cancers: Dose effects on the ocular, orbital and eyelid structures].

    PubMed

    Thariat, J; Racadot, S; Pointreau, Y; Boisselier, P; Grange, J-D; Graff, P; Weber, D C

    2016-10-01

    Radiation-induced damage of ocular, orbital and eyelid structures are mainly reported for the optic nerve, retina, lens and lacrimal gland. Dose-volume relationships are, however, inaccurate due to the small volume of most of the organs at risk involved and limited ability of irradiation techniques to spare these structures in the pre-IMRT (intensity-modulated radiation therapy) era. The ability of newest radiation techniques including IMRT and proton therapy to generate steep dose gradients may yield more accurate models in the future. Some toxicities are severe and irreversible, leading to vision loss, as in the case of radiation-induced optic neuropathy for which curative treatments are suboptimal. Other toxicities can lead to reversible vision loss but can be surgically corrected, as is the case for radiation-induced cataract. In this paper, we will review the dose effects for the ocular; orbital and eyelid structures.

  18. First dose-map measured with a polycrystalline diamond 2D dosimeter under an intensity modulated radiotherapy beam

    NASA Astrophysics Data System (ADS)

    Scaringella, M.; Zani, M.; Baldi, A.; Bucciolini, M.; Pace, E.; de Sio, A.; Talamonti, C.; Bruzzi, M.

    2015-10-01

    A prototype of bidimensional dosimeter made on a 2.5×2.5 cm2 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 cm2. Results show that absorbed doses measured by our pCVD diamond device are consistent with those calculated by the Treatment Planning System (TPS).

  19. [Intensity-modulated radiotherapy of head and neck cancers: Dose effects on the ocular, orbital and eyelid structures].

    PubMed

    Thariat, J; Racadot, S; Pointreau, Y; Boisselier, P; Grange, J-D; Graff, P; Weber, D C

    2016-10-01

    Radiation-induced damage of ocular, orbital and eyelid structures are mainly reported for the optic nerve, retina, lens and lacrimal gland. Dose-volume relationships are, however, inaccurate due to the small volume of most of the organs at risk involved and limited ability of irradiation techniques to spare these structures in the pre-IMRT (intensity-modulated radiation therapy) era. The ability of newest radiation techniques including IMRT and proton therapy to generate steep dose gradients may yield more accurate models in the future. Some toxicities are severe and irreversible, leading to vision loss, as in the case of radiation-induced optic neuropathy for which curative treatments are suboptimal. Other toxicities can lead to reversible vision loss but can be surgically corrected, as is the case for radiation-induced cataract. In this paper, we will review the dose effects for the ocular; orbital and eyelid structures. PMID:27614507

  20. Evaluation of Four-Dimensional Computed Tomography-Based Intensity-Modulated and Respiratory-Gated Radiotherapy Techniques for Pancreatic Carcinoma

    SciTech Connect

    Geld, Ylanga G. van der; Triest, Baukelien van; Verbakel, Wilko; Soernsen de Koste, John R. van; Senan, Suresh; Slotman, Ben J.; Lagerwaard, Frank J.

    2008-11-15

    Purpose: To compare conformal radiotherapy (CRT), intensity-modulated radiotherapy (IMRT), and respiration-gated radiotherapy (RGRT) planning techniques for pancreatic cancer. All target volumes were determined using four-dimensional computed tomography scans (4D CT). Methods and Materials: The pancreatic tumor and enlarged regional lymph nodes were contoured on all 10 phases of a planning 4D CT scan for 10 patients, and the planning target volumes (PTV{sub allphases}) were generated. Three consecutive respiratory phases for RGRT delivery in both inspiration and expiration were identified, and the corresponding PTVs (PTV{sub inspiration} and PTV{sub expiration}) and organ at risk volumes created. Treatment plans using CRT and IMRT, with and without RGRT, were created for each PTV. Results: Compared with the CRT plans, IMRT significantly reduced the mean volume of right kidney exposed to 20 Gy from 27.7% {+-} 17.7% to 16.0% {+-} 18.2% (standard deviation) (p < 0.01), but this was not achieved for the left kidney (11.1% {+-} 14.2% to 5.7% {+-} 6.5%; p = 0.1). The IMRT plans also reduced the mean gastric, hepatic, and small bowel doses (p < 0.01). No additional reductions in the dose to the kidneys or other organs at risk were seen when RGRT plans were combined with either CRT or IMRT, and the findings for RGRT in end-expiration and end-inspiration were similar. Conclusion: 4D CT-based IMRT plans for pancreatic tumors significantly reduced the radiation doses to the right kidney, liver, stomach, and small bowel compared with CRT plans. The additional dosimetric benefits from RGRT appear limited in this setting.

  1. A case study of radiotherapy planning for Intensity Modulation Radiation Therapy for the whole scalp with matching electron treatment

    SciTech Connect

    Sponseller, Patricia; Paravathaneni, Upendra

    2013-07-01

    The purpose of this report is to communicate a technique to match an electron field to the dose distribution of an Intensity-Modulated Radiation Therapy (IMRT) plan. A patient with multiple areas of squamous cell carcinoma over the scalp was treated using 60 Gy in 2.0-Gy fractions to the entire scalp and first echelon nodes with multiple 6-MV photon fields. To deliver an adequate dose to the scalp, a custom 1.0-cm bolus helmet was fashioned using a solid piece of aquaplast. Along with the IMRT scalp treatment, a left zygoma area was treated with electrons matching the anterior border of the IMRT dose distribution. The border was matched by creating a left lateral field with the multileaf collimator shaped to the IMRT dose distribution. The result indicated an adequate dose to the skin match between the IMRT plan and the electron field. Results were confirmed using optically stimulated luminescence placed at the skin match area, so that the dose matched the prescription within 10%.

  2. Obtaining Normal Tissue Constraints Using Intensity Modulated Radiotherapy (IMRT) in Patients with Oral Cavity, Oropharnygeal, and Laryngeal Carcinoma

    SciTech Connect

    Skinner, William K.J.

    2009-01-01

    The purpose of this study was to evaluate normal tissue dose constraints while maintaining planning target volume (PTV) prescription without reducing PTV margins. Sixteen patients with oral cavity carcinoma (group I), 27 patients with oropharyngeal carcinoma (group II), and 28 patients with laryngeal carcinoma (group III) were reviewed. Parotid constraints were a mean dose to either parotid < 26 Gy (PP1), 50% of either parotid < 30 Gy (PP2), or 20 cc of total parotid < 20 Gy (PP3). Treatment was intensity modulated radiation therapy (IMRT) with simultaneous integrated boost (SIB). All patients met constraints for cord and brain stem. The mandibular constraints were met in 66%, 29%, and 57% of patients with oral, oropharyngeal, and laryngeal cancers, respectively. Mean dose of 26 Gy (PP1) was achieved in 44%, 41%, and 38% of oral, oropharyngeal, and laryngeal patients. PP2 (parotid constraint of 30 Gy to less than 50% of one parotid) was the easiest to achieve (group I, II, and III: 82%, 76%, and 78%, respectively). PP3 (20 cc of total parotid < 20 Gy) was difficult, and was achieved in 25%, 17%, and 35% of oral, oropharyngeal, and laryngeal patients, respectively. Mean parotid dose of 26 Gy was met 40% of the time. However, a combination of constraints allowed for sparing of the parotid based on different criteria and was met in high numbers. This was accomplished without reducing PTV-parotid overlap. What dose constraint best correlates with subjective and objective functional outcomes remains a focus for future study.

  3. Anatomic and Dosimetric Changes During the Treatment Course of Intensity-Modulated Radiotherapy for Locally Advanced Nasopharyngeal Carcinoma

    SciTech Connect

    Wang Xin; Lu Jiade; Xiong Xiaopeng; Zhu Guopei; Ying Hongmei; He Shaoqin; Hu Weigang; Hu Chaosu

    2010-07-01

    Many patients with nasopharyngeal carcinoma (NPC) have marked anatomic change during intensity-modulated radiation therapy (IMRT). In this study, the magnitude of anatomic changes and its dosimetric effects were quantified. Fifteen patients with locally advanced NPC treated with IMRT had repeated computed tomography (CT) after 18 fractions. A hybrid plan was made to the anatomy of the second computed tomography scan. The dose of the original plan, hybrid plan, and new plan were compared. The mean volume of left and right parotid decreased 6.19 mL and 6.44 mL, respectively. The transverse diameters of the upper bound of odontoid process, the center of odontoid process, and the center of C2 vertebral body slices contracted with the mean contraction of 8.2 mm, 9.4 mm, and 7.6 mm. Comparing the hybrid plan with the treatment plan, the coverage of target was maintained while the maximum dose to the brain stem and spinal cord increased by 0.08 to 6.51 Gy and 0.05 to 7.8 Gy. The mean dose to left and right parotid increased by 2.97 Gy and 2.57 Gy, respectively. A new plan reduced the dose of spinal cord, brain stem, and parotids. Measurable anatomic changes occurring during the IMRT for locally advanced NPC maintained the coverage of targets but increased the dose to critical organs. Those patients might benefit from replanning.

  4. [Intensity modulated radiotherapy for head and neck cancer, dose constraint for normal tissue: Cochlea vestibular apparatus and brainstem].

    PubMed

    Guimas, V; Thariat, J; Graff-Cailleau, P; Boisselier, P; Pointreau, Y; Pommier, P; Montbarbon, X; Laude, C; Racadot, S

    2016-10-01

    Modern techniques such as intensity modulated radiation therapy (IMRT) have been proven to significantly decrease the dose delivered to the cochleovestibular apparatus, limiting consecutive toxicity especially for sensorineural hearing loss. However, recent data still report a 42% rate of radio-induced hypoacusia underscoring the need to protect the cochleovestibular apparatus. Due to the small size of the cochlea, a precise dose-volume analysis could not be performed, and recommendations only refer to the mean dose. Confusing factors such as age, concomitant chemotherapy, primary site and tumor stage should be taken into account at the time of treatment planning. (Non-coplanar) VMAT and tomotherapy have been proven better at sparing the cochlea in comparison with 3D CRT. Brainstem radio-induced injuries were poorly studied because of their infrequency and the difficulty of distinguishing between necrosis and tumor progression in the case of a primary tumor located at the base of skull. The following toxicities have been described: brainstem focal radionecrosis, cognitive disorders without dementia, cranial nerve injuries and sensori motor disability. Maximal dose to the brainstem should be kept to < 54Gy for conventional fractionation. This dose could be exceeded (no more than 10mL should receive more than 59Gy), provided this hot spot is located in the peripheral area of the organ. PMID:27614519

  5. Dosimetric difference amongst 3 techniques: TomoTherapy, sliding-window intensity-modulated radiotherapy (IMRT), and RapidArc radiotherapy in the treatment of late-stage nasopharyngeal carcinoma (NPC)

    SciTech Connect

    Lee, Francis Kar-ho Yip, Celia Wai-yi; Cheung, Frankie Chun-hung; Leung, Alex Kwok-cheung; Chau, Ricky Ming-chun; Ngan, Roger Kai-cheong

    2014-04-01

    To investigate the dosimetric difference amongst TomoTherapy, sliding-window intensity-modulated radiotherapy (IMRT), and RapidArc radiotherapy in the treatment of late-stage nasopharyngeal carcinoma (NPC). Ten patients with late-stage (Stage III or IV) NPC treated with TomoTherapy or IMRT were selected for the study. Treatment plans with these 3 techniques were devised according to departmental protocol. Dosimetric parameters for organ at risk and treatment targets were compared between TomoTherapy and IMRT, TomoTherapy and RapidArc, and IMRT and RapidArc. Comparison amongst the techniques was done by statistical tests on the dosimetric parameters, total monitor unit (MU), and expected delivery time. All 3 techniques achieved similar target dose coverage. TomoTherapy achieved significantly lower doses in lens and mandible amongst the techniques. It also achieved significantly better dose conformity to the treatment targets. RapidArc achieved significantly lower dose to the eye and normal tissue, lower total MU, and less delivery time. The dosimetric advantages of the 3 techniques were identified in the treatment of late-stage NPC. This may serve as a guideline for selection of the proper technique for different clinical cases.

  6. The use of film dosimetry of the penumbra region to improve the accuracy of intensity modulated radiotherapy

    SciTech Connect

    Arnfield, Mark R.; Otto, Karl; Aroumougame, Vijayan R.; Alkins, Ryan D.

    2005-01-01

    Accurate measurements of the penumbra region are important for the proper modeling of the radiation beam for linear accelerator-based intensity modulated radiation therapy. The usual data collection technique with a standard ionization chamber artificially broadens the measured beam penumbrae due to volume effects. The larger the chamber, the greater is the spurious increase in penumbra width. This leads to inaccuracies in dose calculations of small fields, including small fields or beam segments used in IMRT. This source of error can be rectified by the use of film dosimetry for penumbra measurements because of its high spatial resolution. The accuracy of IMRT calculations with a pencil beam convolution model in a commercial treatment planning system was examined using commissioning data with and without the benefit of film dosimetry of the beam penumbrae. A set of dose-spread kernels of the pencil beam model was calculated based on commissioning data that included beam profiles gathered with a 0.6-cm-i.d. ionization chamber. A second set of dose-spread kernels was calculated using the same commissioning data with the exception of the penumbrae, which were measured with radiographic film. The average decrease in the measured width of the 80%-20% penumbrae of various square fields of size 3-40 cm, at 5 cm depth in water-equivalent plastic was 0.27 cm. Calculations using the pencil beam model after it was re-commissioned using film dosimetry of the penumbrae gave better agreement with measurements of IMRT fields, including superior reproduction of high dose gradient regions and dose extrema. These results show that accurately measuring the beam penumbrae improves the accuracy of the dose distributions predicted by the treatment planning system and thus is important when commissioning beam models used for IMRT.

  7. Kidney-Sparing Methods for Extended-Field Intensity-Modulated Radiotherapy (EF-IMRT) in Cervical Carcinoma Treatment.

    PubMed

    Kunogi, Hiroaki; Yamaguchi, Nanae; Terao, Yasuhisa; Sasai, Keisuke

    2016-01-01

    Coplanar extended-field intensity-modulated radiation therapy (EF-IMRT) targeting the whole-pelvic and para-aortic lymph nodes in patients with advanced cervical cancer results in impaired creatinine clearance. An improvement in renal function cannot be expected unless low-dose (approximately 10 Gy) kidney exposure is reduced. The dosimetric method should be considered during EF-IMRT planning to further reduce low-dose exposure to the kidneys. To assess the usefulness of non-coplanar EF-IMRT with kidney-avoiding beams to spare the kidneys during cervical carcinoma treatment in dosimetric analysis between non-coplanar and coplanar EF-IMRT, we compared the doses of the target organ and organs at risk, including the kidney, in 10 consecutive patients. To estimate the influence of EFRT on renal dysfunction, creatinine clearance values after treatment were also examined in 18 consecutive patients. Of these 18 patients, 10 patients who were included in the dosimetric analysis underwent extended field radiation therapy (EFRT) with concurrent chemotherapy, and eight patients underwent whole-pelvis radiation therapy with concurrent chemotherapy to treat cervical carcinoma between April 2012 and March 2015 at our institution. In the dosimetric analysis, non-coplanar EF-IMRT was effective at reducing low-dose (approximately 10 Gy) exposure to the kidneys, thus maintaining target coverage and sparing other organs at risk, such as the small bowel, rectum, and bladder, compared with coplanar EF-IMRT. Renal function in all 10 patients who underwent EFRT, including coplanar EF-IMRT (with kidney irradiation), was low after treatment, and differed significantly from that of the eight patients who underwent WPRT (no kidney irradiation) 6 months after the first day of treatment (P = 0.005). In conclusion, non-coplanar EF-IMRT should be considered in patients with advanced cervical cancer, particularly in patients with a long life expectancy or with pre-existing renal dysfunction. PMID

  8. Dosimetric implications of residual seminal vesicle motion in fiducial-guided intensity-modulated radiotherapy for prostate cancer

    SciTech Connect

    Stenmark, Matthew H.; Vineberg, Karen; Ten Haken, Randall K.; Hamstra, Daniel A.; Feng, Mary

    2012-10-01

    To determine whether residual interfraction seminal vesicle (SV) displacement necessitates specific planning target volume (PTV) margins during fiducial-guided intensity modulated radiation therapy (IMRT) of the prostate. A planning computed tomography (CT) scan and 2 subsequent CT scans were prospectively obtained for 20 prostate cancer patients with intraprostatic fiducial markers. After CT registration, SV displacement relative to the prostate was quantified as a function of margin size for both the proximal (1 cm) SV (PSV) and the full SV (FSV). Two IMRT plans were simulated for each patient (prostate + PSV and prostate + FSV) both with a uniform 5-mm PTV margin. Minimum clinical target volume (CTV) dose (D{sub min}) and the volume of SV receiving 95% of the prescription dose (V{sub 95%}) were assessed during treatment and compared with the initial plan. In all cases, SV displacement with respect to the prostate was greater for the FSV compared with the PSV. To ensure at least 95% geometrical coverage of the CTV for 90% of patients, margins of 5 and 8 mm were required for the PSV and FSV, respectively. Dosimetrically, residual SV displacement had minimal impact on PSV coverage compared with FSV coverage. For the PSV D{sub min} was {>=}95% of the prescribed dose in 90% of patients with an overall mean V{sub 95%} of 99.6 {+-} 0.8%; for the FSV D{sub min} was {>=}95% of the prescribed dose in only 45% of patients with a mean V{sub 95%} of 97.9 {+-} 2.4%. The SVs move differentially from the prostate and exhibit greater variation with increasing distance from the prostate. For plans targeting just the prostate and PSVs, 5-mm PTV expansions are adequate. However, despite daily localization of the prostate, larger PTV margins are required for cases where the intent is to completely cover the FSV.

  9. Intensity-modulated radiotherapy for nasopharyngeal carcinoma: Clinical correlation of dose to the pharyngo-esophageal axis and dysphagia

    SciTech Connect

    Fua, Tsien F. . E-mail: tsien-fei.fua@petermac.org; Corry, June; Milner, Alvin D.; Cramb, Jim; Walsham, Sue F.; Peters, Lester J.

    2007-03-15

    Purpose: The aim of this study was to quantify the dose delivered to the pharyngo-esophageal axis using different intensity-modulated radiation therapy (IMRT) techniques for treatment of nasopharyngeal carcinoma and to correlate this with acute swallowing toxicity. Methods and Materials: The study population consisted of 28 patients treated with IMRT between February 2002 and August 2005: 20 with whole field IMRT (WF-IMRT) and 8 with IMRT fields junctioned with an anterior neck field with central shielding (j-IMRT). Dose to the pharyngo-esophageal axis was measured using dose-volume histograms. Acute swallowing toxicity was assessed by review of dysphagia grade during treatment and enteral feeding requirements. Results: The mean pharyngo-esophageal dose was 55.2 Gy in the WF-IMRT group and 27.2 Gy in the j-IMRT group, p < 0.001. Ninety-five percent (19/20) of the WF-IMRT group developed Grade 3 dysphagia compared with 62.5% (5/8) of the j-IMRT group, p = 0.06. Feeding tube duration was a median of 38 days for the WF-IMRT group compared with 6 days for the j-IMRT group, p = 0.04. Conclusions: Clinical vigilance must be maintained when introducing new technology to ensure that unanticipated adverse effects do not result. Although newer planning systems can reduce the dose to the pharyngo-esophageal axis with WF-IMRT, the j-IMRT technique is preferred at least in patients with no gross disease in the lower neck.

  10. Intensity-modulated radiotherapy for gliomas:dosimetric effects of changes in gross tumor volume on organs at risk and healthy brain tissue

    PubMed Central

    Yang, Zhen; Zhang, Zijian; Wang, Xia; Hu, Yongmei; Lyu, Zhiping; Huo, Lei; Wei, Rui; Fu, Jun; Hong, Jidong

    2016-01-01

    Aim The aim of this study was to explore the effects of changes in the gross tumor volume (GTV) on dose distribution in organs at risk (OARs) and healthy brain tissue in patients with gliomas. Methods Eleven patients suffering from gliomas with intensity-modulated radiotherapy (IMRT) plans treated with a simultaneous integrated boost technique planned before therapy (initial plans) were prospectively enrolled. At the end of radiotherapy, patients underwent repeat computed tomography and magnetic resonance imaging, and IMRT was replanned. The GTV and dosimetric parameters between the initial and replanned IMRT were compared using the Wilcoxon two-related-sample test, and correlations between the initial GTV and the replanned target volumes were assessed using the bivariate correlation test. Results The volume of the residual tumor did not change significantly (P>0.05), the volume of the surgical cavity decreased significantly (P<0.05), and the GTV and target volumes decreased significantly at the end of IMRT (all P<0.05). The near-maximum dose to OARs and volumes of healthy brain tissue receiving total doses of 10–50 Gy were lower in the replanned IMRT than in the initial IMRT (all P<0.05). The GTV in the initial plan was significantly positively correlated with the changes in the GTV and planning target volume 1 that occurred during IMRT (all P<0.05). Conclusion The reduction in the GTV in patients with gliomas resulted from shrinkage of the surgical cavity during IMRT, leading to decreased doses to the OARs and healthy brain tissue. Such changes appeared to be most meaningful in patients with large initial GTV values. PMID:27366091

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

    PubMed Central

    Ling, Ted C.; Slater, Jerry M.; Nookala, Prashanth; Mifflin, Rachel; Grove, Roger; Ly, Anh M.; Patyal, Baldev; Slater, Jerry D.; Yang, Gary Y.

    2014-01-01

    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. PMID:25489937

  12. A quantitative assessment of volumetric and anatomic changes of the parotid gland during intensity-modulated radiotherapy for head and neck cancer using serial computed tomography

    SciTech Connect

    Ajani, Abdallah A.; Qureshi, Muhammad M.; Kovalchuk, Nataliya; Orlina, Lawrence; Sakai, Osamu; Truong, Minh Tam

    2013-10-01

    To evaluate the change in volume and movement of the parotid gland measured by serial contrast-enhanced computed tomography scans in patients with head and neck cancer treated with parotid-sparing intensity-modulated radiotherapy (IMRT). A prospective study was performed on 13 patients with head and neck cancer undergoing dose-painted IMRT to 69.96 Gy in 33 fractions. Serial computed tomography scans were performed at baseline, weeks 2, 4, and 6 of radiotherapy (RT), and at 6 weeks post-RT. The parotid volume was contoured at each scan, and the movement of the medial and lateral borders was measured. The patient's body weight was recorded at each corresponding week during RT. Regression analyses were performed to ascertain the rate of change during treatment as a percent change per fraction in parotid volume and distance relative to baseline. The mean parotid volume decreased by 37.3% from baseline to week 6 of RT. The overall rate of change in parotid volume during RT was−1.30% per fraction (−1.67% and−0.91% per fraction in≥31 Gy and<31 Gy mean planned parotid dose groups, respectively, p = 0.0004). The movement of parotid borders was greater in the≥31 Gy mean parotid dose group compared with the<31 Gy group (0.22% per fraction and 0.14% per fraction for the lateral border and 0.19% per fraction and 0.06% per fraction for the medial border, respectively). The median change in body weight was−7.4% (range, 0.75% to−17.5%) during RT. A positive correlation was noted between change in body weight and parotid volume during the course of RT (Spearman correlation coefficient, r = 0.66, p<0.01). Head and neck IMRT results in a volume loss of the parotid gland, which is related to the planned parotid dose, and the patient's weight loss during RT.

  13. Intensity-Modulated Radiotherapy is Associated With Improved Global Quality of Life Among Long-term Survivors of Head-and-Neck Cancer

    SciTech Connect

    Chen, Allen M.; Farwell, D. Gregory; Luu, Quang; Vazquez, Esther G.; Lau, Derick H.; Purdy, James A.

    2012-09-01

    Purpose: To compare the long-term quality of life among patients treated with and without intensity-modulated radiotherapy (IMRT) for head-and-neck cancer. Methods and Materials: University of Washington Quality of Life instrument scores were reviewed for 155 patients previously treated with radiation therapy for locally advanced head-and-neck cancer. All patients were disease free and had at least 2 years of follow-up. Eighty-four patients (54%) were treated with IMRT. The remaining 71 patients (46%) were treated with three-dimensional conformal radiotherapy (3D CRT) by use of initial opposed lateral fields matched to a low anterior neck field. Results: The mean global quality of life scores were 67.5 and 80.1 for the IMRT patients at 1 and 2 years, respectively, compared with 55.4 and 57.0 for the 3D CRT patients, respectively (p < 0.001). At 1 year after the completion of radiation therapy, the proportion of patients who rated their global quality of life as 'very good' or 'outstanding' was 51% and 41% among patients treated by IMRT and 3DCRT, respectively (p = 0.11). At 2 years, the corresponding percentages increased to 73% and 49%, respectively (p < 0.001). On multivariate analysis accounting for sex, age, radiation intent (definitive vs. postoperative), radiation dose, T stage, primary site, use of concurrent chemotherapy, and neck dissection, the use of IMRT was the only variable independently associated with improved quality of life (p = 0.01). Conclusion: The early quality of life improvements associated with IMRT not only are maintained but apparently become more magnified over time. These data provide powerful evidence attesting to the long-term benefits of IMRT for head-and-neck cancer.

  14. Intensity-Modulated Radiotherapy for Complex-Shaped Meningioma of the Skull Base: Long-Term Experience of a Single Institution

    SciTech Connect

    Milker-Zabel, Stefanie . E-mail: Stefanie_Milker-Zabel@med.uni-heidelberg.de; Zabel-du Bois, Angelika; Huber, Peter; Schlegel, Wolfgang; Debus, Juergen

    2007-07-01

    Purpose: We analyzed our long-term experience with intensity-modulated radiotherapy (IMRT) in patients with complex-shaped meningioma of the skull base. Patients and Methods: Between January 1998 and December 2004, 94 patients with complex-shaped meningioma were treated using IMRT at our institution. Tumor distribution was: World Health Organization (WHO) Grade 1 in 54.3%, WHO Grade 2 in 9.6%, and WHO Grade 3 in 4.2%. In 31.9% of patients, the clinical and radiologic characteristics of the tumor were consistent with the diagnosis of meningioma. Twenty-six patients received radiotherapy as primary treatment and 14 patients postoperative for residual disease. Fifty-four patients were treated after local recurrence. Median target volume was 81.4 mL, median total dose was 57.6 Gy given in 32 fractions. Results: Median follow-up was 4.4 years. Overall local control was 93.6%. Sixty-nine patients had stable disease based on computed tomography/magnetic resonance imaging (MRI), whereas 19 had a tumor volume reduction after IMRT. Six patients showed local tumor progression on MRI 22.3 months' median after IMRT. Three patients died from non-treatment-related conditions after IMRT. In 39.8% of the patients, preexisting neurologic deficits improved. Worsening of preexisting neurologic symptoms was seen in 4 patients and 2 patients developed new clinical symptoms from local tumor progression. Transient side effects such as headache were seen in 7 patients. Treatment-induced loss of vision was seen in 1 of 53 reirradiated patients with a Grade 3 meningioma 9 months after retreatment with IMRT. Conclusion: These data demonstrate that IMRT is an effective and safe treatment modality for long-term local control of complex-shaped and otherwise difficult to treat meningioma.

  15. WE-G-BRF-01: Adaptation to Intrafraction Tumor Deformation During Intensity-Modulated Radiotherapy: First Proof-Of-Principle Demonstration

    SciTech Connect

    Ge, Y; OBrien, R; Shieh, C; Booth, J; Keall, P

    2014-06-15

    Purpose: Intrafraction tumor deformation limits targeting accuracy in radiotherapy and cannot be adapted to by current motion management techniques. This study simulated intrafractional treatment adaptation to tumor deformations using a dynamic Multi-Leaf Collimator (DMLC) tracking system during Intensity-modulated radiation therapy (IMRT) treatment for the first time. Methods: The DMLC tracking system was developed to adapt to the intrafraction tumor deformation by warping the planned beam aperture guided by the calculated deformation vector field (DVF) obtained from deformable image registration (DIR) at the time of treatment delivery. Seven single phantom deformation images up to 10.4 mm deformation and eight tumor system phantom deformation images up to 21.5 mm deformation were acquired and used in tracking simulation. The intrafraction adaptation was simulated at the DMLC tracking software platform, which was able to communicate with the image registration software, reshape the instantaneous IMRT field aperture and log the delivered MLC fields.The deformation adaptation accuracy was evaluated by a geometric target coverage metric defined as the sum of the area incorrectly outside and inside the reference aperture. The incremental deformations were arbitrarily determined to take place equally over the delivery interval. The geometric target coverage of delivery with deformation adaptation was compared against the delivery without adaptation. Results: Intrafraction deformation adaptation during dynamic IMRT plan delivery was simulated for single and system deformable phantoms. For the two particular delivery situations, over the treatment course, deformation adaptation improved the target coverage by 89% for single target deformation and 79% for tumor system deformation compared with no-tracking delivery. Conclusion: This work demonstrated the principle of real-time tumor deformation tracking using a DMLC. This is the first step towards the development of an

  16. SU-E-T-275: Radiobiological Evaluation of Intensity Modulated Radiotherapy Treatment for Locally Advanced Head and Neck Squamous Cell Carcinomas

    SciTech Connect

    Rekha Reddy, B.; Ravikumar, M.; Tanvir Pasha, C.R; Anil Kumar, M.R; Varatharaj, C.; Pyakuryal, A; Narayanasamy, Ganesh

    2014-06-01

    Purpose: To evaluate the radiobiological outcome of Intensity Modulated Radiotherapy Treatment (IMRT) for locally advanced head and neck squamous cell carcinomas using HART (Histogram Analysis in Radiation Therapy; J Appl Clin Med Phys 11(1): 137–157, 2010) program and compare with the clinical outcomes. Methods: We have treated 20 patients of stage III and IV HNSCC Oropharynx and hypopharynx with accelerated IMRT technique and concurrent chemotherapy. Delineation of tumor and normal tissues were done using Danish Head and Neck Cancer Group (DAHANCA) contouring guidelines and radiotherapy was delivered to a dose of 70Gy in 35 fractions to the primary and involved lymph nodes, 63Gy to intermediate risk areas and 56 Gy to lower risk areas, Monday to Saturday, 6 Days/week using 6 MV Photons with an expected overall treatment time of 6 weeks. The TCP and NTCP's were calculated from the dose-volume histogram (DVH) statistics using the Poisson Statistics (PS) and JT Lyman models respectively and the Resultwas correlated with clinical outcomes of the patients with mean follow up of 24 months. Results: Using HART program, the TCP (0.89± 0.01) of primary tumor and the NTCP for parotids (0.20±0.12), spinal cord (0.05±0.01), esophagus (0.30±0.2), mandible (0.35±0.21), Oral cavity (0.37±0.18), Larynx (0.30±0.15) were estimated and correlated with clinical outcome of the patients. Conclusion: Accelerated IMRT with Chemotherapy is a clinical feasible option in the treatment of locally advanced HNSCC with encouraging initial tumour response and acceptable acute toxicities. The correlation between the clinical outcomes and radiobiological model estimated parameters using HART programs are found to be satisfactory.

  17. Image-guided intensity-modulated radiotherapy for prostate cancer: Dose constraints for the anterior rectal wall to minimize rectal toxicity

    SciTech Connect

    Peterson, Jennifer L.; Buskirk, Steven J.; Heckman, Michael G.; Diehl, Nancy N.; Bernard, Johnny R.; Tzou, Katherine S.; Casale, Henry E.; Bellefontaine, Louis P.; Serago, Christopher; Kim, Siyong; Vallow, Laura A.; Daugherty, Larry C.; Ko, Stephen J.

    2014-04-01

    Rectal adverse events (AEs) are a major concern with definitive radiotherapy (RT) treatment for prostate cancer. The anterior rectal wall is at the greatest risk of injury as it lies closest to the target volume and receives the highest dose of RT. This study evaluated the absolute volume of anterior rectal wall receiving a high dose to identify potential ideal dose constraints that can minimize rectal AEs. A total of 111 consecutive patients with Stage T1c to T3a N0 M0 prostate cancer who underwent image-guided intensity-modulated RT at our institution were included. AEs were graded according to the Common Terminology Criteria for Adverse Events, version 4.0. The volume of anterior rectal wall receiving 5 to 80 Gy in 2.5-Gy increments was determined. Multivariable Cox regression models were used to identify cut points in these volumes that led to an increased risk of early and late rectal AEs. Early AEs occurred in most patients (88%); however, relatively few of them (13%) were grade ≥2. At 5 years, the cumulative incidence of late rectal AEs was 37%, with only 5% being grade ≥2. For almost all RT doses, we identified a threshold of irradiated absolute volume of anterior rectal wall above which there was at least a trend toward a significantly higher rate of AEs. Most strikingly, patients with more than 1.29, 0.73, or 0.45 cm{sup 3} of anterior rectal wall exposed to radiation doses of 67.5, 70, or 72.5 Gy, respectively, had a significantly increased risk of late AEs (relative risks [RR]: 2.18 to 2.72; p ≤ 0.041) and of grade ≥ 2 early AEs (RR: 6.36 to 6.48; p = 0.004). Our study provides evidence that definitive image-guided intensity-modulated radiotherapy (IG-IMRT) for prostate cancer is well tolerated and also identifies dose thresholds for the absolute volume of anterior rectal wall above which patients are at greater risk of early and late complications.

  18. Three-dimensional customized bolus for intensity-modulated radiotherapy in a patient with Kimura's disease involving the auricle.

    PubMed

    Park, J W; Yea, J W

    2016-05-01

    In radiotherapy, a commercial bolus often does not provide a suitable fit over irregular surfaces. To address this issue, we fabricated a customized bolus using 3D printing technology. The aim of our study was to evaluate the application of this 3D-printed bolus in a clinical setting. The patient was a 45-year-old man with recurrent Kimura's disease involving the auricle, receiving radiotherapy in our oncology department. A customized bolus, 5mm in thickness, was fabricated based on reconstruction of computed tomography (CT) images. The bolus was printed on a Dimension 1200 series SST 3D printer. Repeat CT-based simulation indicated an acceptable fit of the 3D-printed bolus to the target region, with a maximum air gap of less than 5mm at the tragus. Most of the surface area of the target region was covered by the 95% isodose line. The plan with the 3D-printed bolus improved target coverage compared to that without a bolus. And the plan with the 3D-printed bolus yielded comparable results to those with the paraffin wax bolus. In conclusion, a customized bolus using a 3D printer was successfully applied to an irregular surface. PMID:27020714

  19. Dosimetric effects of multileaf collimator leaf width on intensity-modulated radiotherapy for head and neck cancer

    SciTech Connect

    Hong, Chae-Seon; Ju, Sang Gyu Kim, Minkyu; Kim, Jin Man; Han, Youngyih; Ahn, Yong Chan; Choi, Doo Ho; Park, Hee Chul; Kim, Jung-in; Nam, Heerim; Suh, Tae-Suk

    2014-02-15

    Purpose: The authors evaluated the effects of multileaf collimator (MLC) leaf width (2.5 vs. 5 mm) on dosimetric parameters and delivery efficiencies of intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) for head and neck (H and N) cancers. Methods: The authors employed two types of mock phantoms: large-sized head and neck (LH and N) and small-sized C-shape (C-shape) phantoms. Step-and-shoot IMRT (S and S-IMRT) and VMAT treatment plans were designed with 2.5- and 5.0-mm MLC for both C-shape and LH and N phantoms. Their dosimetric characteristics were compared in terms of the conformity index (CI) and homogeneity index (HI) for the planning target volume (PTV), the dose to organs at risk (OARs), and the dose-spillage volume. To analyze the effects of the field and arc numbers, 9-field IMRT (9F-IMRT) and 13-field IMRT (13F-IMRT) plans were established for S and S-IMRT. For VMAT, single arc (VMAT{sub 1}) and double arc (VMAT{sub 2}) plans were established. For all plans, dosimetric verification was performed using the phantom to examine the relationship between dosimetric errors and the two leaf widths. Delivery efficiency of the two MLCs was compared in terms of beam delivery times, monitor units (MUs) per fraction, and the number of segments for each plan. Results: 2.5-mm MLC showed better dosimetric characteristics in S and S-IMRT and VMAT for C-shape, providing better CI for PTV and lower spinal cord dose and high and intermediate dose-spillage volume as compared with the 5-mm MLC (p < 0.05). However, no significant dosimetric benefits were provided by the 2.5-mm MLC for LH and N (p > 0.05). Further, beam delivery efficiency was not observed to be significantly associated with leaf width for either C-shape or LH and N. However, MUs per fraction were significantly reduced for the 2.5-mm MLC for the LH and N. In dosimetric error analysis, absolute dose evaluations had errors of less than 3%, while the Gamma passing rate was

  20. Dosimetric benefit of DMLC tracking for conventional and sub-volume boosted prostate intensity-modulated arc radiotherapy

    PubMed Central

    Pommer, Tobias; Falk, Marianne; Poulsen, Per R.; Keall, Paul J.; O’Brien, Ricky T.; Petersen, Peter Meidahl; Rosenschöld, Per Munck af

    2013-01-01

    This study investigated the dosimetric impact of uncompensated motion and motion compensation with dynamic multileaf collimator (DMLC) tracking for prostate intensity modulated arc therapy. Two treatment approaches were investigated; a conventional approach with a uniform radiation dose to the target volume and an intraprostatic lesion (IPL) boosted approach with an increased dose to a subvolume of the prostate. The impact on plan quality of optimizations with a leaf position constraint, which limited the distance between neighbouring adjacent MLC leaves, was also investigated. Deliveries were done with and without DMLC tracking on a linear acceleration with a high-resolution MLC. A cylindrical phantom containing two orthogonal diode arrays was used for dosimetry. A motion platform reproduced six patient-derived prostate motion traces, with the average displacement ranging from 1.0 to 8.9 mm during the first 75 seconds. A research DMLC tracking system was used for real-time motion compensation with optical monitoring for position input. The gamma index was used for evaluation, with measurements with a static phantom or the planned dose as reference, using 2% and 2 mm gamma criteria. The average pass rate with DMLC tracking was 99.9% (range 98.7–100%, measurement as reference), whereas the pass rate for untracked deliveries decreased distinctly as the average displacement increased, with an average pass rate of 61.3% (range 32.7–99.3%). Dose-volume histograms showed that DMLC tracking maintained the planned dose distributions in the presence of motion whereas traces with > 3 mm average displacement caused clear plan degradation for untracked deliveries. The dose to the rectum and bladder had an evident dependence on the motion direction and amplitude for untracked deliveries, and the dose to the rectum was slightly increased for IPL boosted plans compared to conventional plans for anterior motion with large amplitude. In conclusion, optimization using a leaf

  1. Comparison of Three-Dimensional (3D) Conformal Proton Radiotherapy (RT), 3D Conformal Photon RT, and Intensity-Modulated RT for Retroperitoneal and Intra-Abdominal Sarcomas

    SciTech Connect

    Swanson, Erika L.; Indelicato, Daniel J.; Louis, Debbie; Flampouri, Stella; Li, Zuofeng; Morris, Christopher G.; Paryani, Nitesh; Slopsema, Roelf

    2012-08-01

    Purpose: To compare three-dimensional conformal proton radiotherapy (3DCPT), intensity-modulated photon radiotherapy (IMRT), and 3D conformal photon radiotherapy (3DCRT) to predict the optimal RT technique for retroperitoneal sarcomas. Methods and Materials: 3DCRT, IMRT, and 3DCPT plans were created for treating eight patients with retroperitoneal or intra-abdominal sarcomas. The clinical target volume (CTV) included the gross tumor plus a 2-cm margin, limited by bone and intact fascial planes. For photon plans, the planning target volume (PTV) included a uniform expansion of 5 mm. For the proton plans, the PTV was nonuniform and beam-specific. The prescription dose was 50.4 Gy/Cobalt gray equivalent CGE. Plans were normalized so that >95% of the CTV received 100% of the dose. Results: The CTV was covered adequately by all techniques. The median conformity index was 0.69 for 3DCPT, 0.75 for IMRT, and 0.51 for 3DCRT. The median inhomogeneity coefficient was 0.062 for 3DCPT, 0.066 for IMRT, and 0.073 for 3DCRT. The bowel median volume receiving 15 Gy (V15) was 16.4% for 3DCPT, 52.2% for IMRT, and 66.1% for 3DCRT. The bowel median V45 was 6.3% for 3DCPT, 4.7% for IMRT, and 15.6% for 3DCRT. The median ipsilateral mean kidney dose was 22.5 CGE for 3DCPT, 34.1 Gy for IMRT, and 37.8 Gy for 3DCRT. The median contralateral mean kidney dose was 0 CGE for 3DCPT, 6.4 Gy for IMRT, and 11 Gy for 3DCRT. The median contralateral kidney V5 was 0% for 3DCPT, 49.9% for IMRT, and 99.7% for 3DCRT. Regardless of technique, the median mean liver dose was <30 Gy, and the median cord V50 was 0%. The median integral dose was 126 J for 3DCPT, 400 J for IMRT, and 432 J for 3DCRT. Conclusions: IMRT and 3DCPT result in plans that are more conformal and homogenous than 3DCRT. Based on Quantitative Analysis of Normal Tissue Effects in Clinic benchmarks, the dosimetric advantage of proton therapy may be less gastrointestinal and genitourinary toxicity.

  2. Comparison of bone marrow sparing intensity modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT) in carcinoma of anal canal: a prospective study

    PubMed Central

    Rattan, Rajit; Bahl, Amit; Gupta, Rajesh; Oinam, Arun S.; Kaur, Satinder

    2016-01-01

    Background Chemoradiation (CRT) is the standard of care in anal canal carcinoma. CRT leads to suppression of iliac bone marrow (BM) leading to hematological toxicity. Intensity modulated radiation therapy (IMRT) technique can be used to decrease radiation dose to iliac BM and thus decrease haematological toxicity. This study aims to compare the haematological and gastrointestinal toxicity in BM sparing IMRT with three-dimensional conformal radiation therapy (3DCRT) in anal carcinoma patients. Methods Twenty untreated, biopsy proven anal canal carcinoma (stages I–III) patients were randomized into IMRT and 3DCRT arm. All patients received CRT with 45 Gy in 25 fractions at 1.8 Gy/fraction and weekly concurrent inj. cisplatin and 5-FU. Patients were evaluated for acute haematological and gastrointestinal toxicity during treatment. Additional dosimetric comparison was made between the two groups. Results Incidence of worst hematological toxicity grade II (GII) and GIII was seen in 40% [4] vs. 30% [3] and 20% [2] vs. 0% [0] respectively, in 3DCRT and IMRT group. However these did not come as statistically significant (P=0.228). Incidence of worst gastrointestinal toxicity during treatment in terms of GII was 30% [3] vs. 50% [5] and GIII was 60% [6] vs. 0% [0] in 3DCRT and IMRT group respectively (P=0.010). Other parameters indicating better tolerance of treatment with IMRT arm than 3DCRT arm were lesser need for administration of parenteral fluid 10% [1] vs. 60% [6] (P=0.019); lesser need for blood transfusion 0% [0] vs. 20% [2] (P=0.060) in IMRT arm than in 3DCRT arm respectively. Patient requiring supportive care during treatment like need for anti-motility drugs and WHO. Step II analgesics also favored IMRT arm. Overall treatment time for Arm B (33.40 days) was less than what was seen in Arm A patients (36.8 days), although difference was not statistically significant (P=0.569). In terms of dosimetric analysis, arm B with the use of IMRT showed superiority over arm

  3. LASSO-based NTCP model for radiation-induced temporal lobe injury developing after intensity-modulated radiotherapy of nasopharyngeal carcinoma

    PubMed Central

    Kong, Cheng; Zhu, Xiang-zhi; Lee, Tsair-Fwu; Feng, Ping-bo; Xu, Jian-hua; Qian, Pu-dong; Zhang, Lan-fang; He, Xia; Huang, Sheng-fu; Zhang, Yi-qin

    2016-01-01

    We investigated the incidence of temporal lobe injury (TLI) in 132 nasopharyngeal carcinoma (NPC) patients who had undergone intensity-modulated radiotherapy (IMRT) in our hospital between March 2005 and November 2009; and identified significant dosimetric predictors of TLI development. Contrast-enhanced lesions or cysts in the temporal lobes, as detected by magnetic resonance imaging (MRI), were regarded as radiation-induced TLIs. We used the least absolute shrinkage and selection operator (LASSO) method to select Dmax (the maximum point dose) and the D1cc (the top dose delivered to a 1-mL volume) from 15 dose-volume-histogram-associated and four clinically relevant candidate factors; the Dmax and the D1cc were the most significant predictors of TLI development. We drew dose-response curves for Dmax and D1cc. The tolerance dose (TD) for the 5% and 50% probabilities of TLI development were 69.0 ± 1.6 and 82.1 ± 2.4 Gy for Dmax and 62.8 ± 2.2 and 80.9 ± 3.4 Gy for D1cc, respectively. The incidence of TLI in NPC patients after IMRT was higher than expected because the therapeutic window is narrow. High-quality longitudinal studies are needed to gain further insight into the complex spatiotemporal effects of non-uniform irradiation on TLI development in NPC patients. PMID:27210263

  4. Dose-volume relationships for moderate or severe neck muscle atrophy after intensity-modulated radiotherapy in patients with nasopharyngeal carcinoma

    PubMed Central

    Zhang, Lu-Lu; Wang, Xiao-Ju; Zhou, Guan-Qun; Tang, Ling-Long; Lin, Ai-Hua; Ma, Jun; Sun, Ying

    2015-01-01

    This study aimed to identify the dosimetric parameters and radiation dose tolerances associated with moderate or severe sternocleidomastoid muscle (SCM) atrophy after intensity-modulated radiotherapy (IMRT) in nasopharyngeal carcinoma (NPC). We retrospectively analysed 138 patients treated with IMRT between 2011 and 2012 for whom IMRT treatment plans and pretreatment and 3-year post-IMRT MRI scans were available. The association between mean dose (Dmean), maximum dose (Dmax), VX (% SCM volume that received more than X Gy), DX (dose to X% of the SCM volume) at X values of 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80 and SCM atrophy at 3 years after IMRT were analyzed. All dosimetric parameters, except V40, V50 and V80, were significantly associated with moderate or severe SCM atrophy. Multivariate analysis showed that V65 was an independent predictor of moderate or severe SCM atrophy (P < 0.001). Receiver operating characteristic (ROC) curve indicated a V65 of 21.47% (area under ROC curves, 0.732; P < 0.001) was the tolerated dose for moderate or severe SCM atrophy. We suggest a limit of 21.47% for V65 to optimize NPC treatment planning, whilst minimizing the risk of moderate or severe SCM atrophy. PMID:26678599

  5. Consensus Guidelines for Delineation of Clinical Target Volume for Intensity-Modulated Pelvic Radiotherapy for the Definitive Treatment of Cervix Cancer

    SciTech Connect

    Lim, Karen; Portelance, Lorraine; Creutzberg, Carien; Juergenliemk-Schulz, Ina M.; Mundt, Arno; Mell, Loren K.; Mayr, Nina; Viswanathan, Akila; Jhingran, Anuja; Erickson, Beth; De Los Santos, Jennifer; Gaffney, David; Yashar, Catheryn; Beriwal, Sushil; Wolfson, Aaron

    2011-02-01

    Purpose: Accurate target definition is vitally important for definitive treatment of cervix cancer with intensity-modulated radiotherapy (IMRT), yet a definition of clinical target volume (CTV) remains variable within the literature. The aim of this study was to develop a consensus CTV definition in preparation for a Phase 2 clinical trial being planned by the Radiation Therapy Oncology Group. Methods and Materials: A guidelines consensus working group meeting was convened in June 2008 for the purposes of developing target definition guidelines for IMRT for the intact cervix. A draft document of recommendations for CTV definition was created and used to aid in contouring a clinical case. The clinical case was then analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with kappa statistics as a measure of agreement between participants. Results: Nineteen experts in gynecological radiation oncology generated contours on axial magnetic resonance images of the pelvis. Substantial STAPLE agreement sensitivity and specificity values were seen for gross tumor volume (GTV) delineation (0.84 and 0.96, respectively) with a kappa statistic of 0.68 (p < 0.0001). Agreement for delineation of cervix, uterus, vagina, and parametria was moderate. Conclusions: This report provides guidelines for CTV definition in the definitive cervix cancer setting for the purposes of IMRT, building on previously published guidelines for IMRT in the postoperative setting.

  6. Effect of MLC leaf position, collimator rotation angle, and gantry rotation angle errors on intensity-modulated radiotherapy plans for nasopharyngeal carcinoma

    SciTech Connect

    Bai, Sen; Li, Guangjun; Wang, Maojie; Jiang, Qinfeng; Zhang, Yingjie; Wei, Yuquan

    2013-07-01

    The purpose of this study was to investigate the effect of multileaf collimator (MLC) leaf position, collimator rotation angle, and accelerator gantry rotation angle errors on intensity-modulated radiotherapy plans for nasopharyngeal carcinoma. To compare dosimetric differences between the simulating plans and the clinical plans with evaluation parameters, 6 patients with nasopharyngeal carcinoma were selected for simulation of systematic and random MLC leaf position errors, collimator rotation angle errors, and accelerator gantry rotation angle errors. There was a high sensitivity to dose distribution for systematic MLC leaf position errors in response to field size. When the systematic MLC position errors were 0.5, 1, and 2 mm, respectively, the maximum values of the mean dose deviation, observed in parotid glands, were 4.63%, 8.69%, and 18.32%, respectively. The dosimetric effect was comparatively small for systematic MLC shift errors. For random MLC errors up to 2 mm and collimator and gantry rotation angle errors up to 0.5°, the dosimetric effect was negligible. We suggest that quality control be regularly conducted for MLC leaves, so as to ensure that systematic MLC leaf position errors are within 0.5 mm. Because the dosimetric effect of 0.5° collimator and gantry rotation angle errors is negligible, it can be concluded that setting a proper threshold for allowed errors of collimator and gantry rotation angle may increase treatment efficacy and reduce treatment time.

  7. Baseline Serum Lactate Dehydrogenase Levels for Patients Treated With Intensity-Modulated Radiotherapy for Nasopharyngeal Carcinoma: A Predictor of Poor Prognosis and Subsequent Liver Metastasis

    SciTech Connect

    Zhou Guanqun; Tang Linglong; Mao Yanping; Chen Lei; Li Wenfei; Sun Ying; Liu Lizhi; Li Li; Lin Aihua; Ma Jun

    2012-03-01

    Purpose: To evaluate the prognostic value of baseline serum lactate dehydrogenase (LDH) levels in patients with nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT). Methods and Materials: Cases of NPC (n = 465) that involved treatment with IMRT with or without chemotherapy were retrospectively analyzed. Results: The mean ({+-}SD) and median baseline serum LDH levels for this cohort were 172.77 {+-} 2.28 and 164.00 IU/L, respectively. Levels of LDH were significantly elevated in patients with locoregionally advanced disease (p = 0.016). Elevated LDH levels were identified as a prognostic factor for rates of overall survival (OS), disease-free survival (DFS), and distant metastasis-free survival (DMFS), with p values <0.001 in the univariate analysis and p < 0.001, p = 0.004, and p = 0.003, respectively, in the multivariate analysis. Correspondingly, the prognostic impact of patient LDH levels was found to be statistically significant for rates of OS, DFS, and DMFS (p = 0.028, 0.024, and 0.020, respectively). For patients who experienced subsequent liver failure after treatment, markedly higher pretreatment serum LDH levels were detected compared with patients experiencing distant metastasis events at other sites (p = 0.032). Conclusions: Elevated baseline LDH levels are associated with clinically advanced disease and are a poor prognosticator for OS, DFS, and DMFS for NPC patients. These results suggest that elevated serum levels of LDH should be considered when evaluating treatment options.

  8. LASSO-based NTCP model for radiation-induced temporal lobe injury developing after intensity-modulated radiotherapy of nasopharyngeal carcinoma.

    PubMed

    Kong, Cheng; Zhu, Xiang-Zhi; Lee, Tsair-Fwu; Feng, Ping-Bo; Xu, Jian-Hua; Qian, Pu-Dong; Zhang, Lan-Fang; He, Xia; Huang, Sheng-Fu; Zhang, Yi-Qin

    2016-01-01

    We investigated the incidence of temporal lobe injury (TLI) in 132 nasopharyngeal carcinoma (NPC) patients who had undergone intensity-modulated radiotherapy (IMRT) in our hospital between March 2005 and November 2009; and identified significant dosimetric predictors of TLI development. Contrast-enhanced lesions or cysts in the temporal lobes, as detected by magnetic resonance imaging (MRI), were regarded as radiation-induced TLIs. We used the least absolute shrinkage and selection operator (LASSO) method to select Dmax (the maximum point dose) and the D1cc (the top dose delivered to a 1-mL volume) from 15 dose-volume-histogram-associated and four clinically relevant candidate factors; the Dmax and the D1cc were the most significant predictors of TLI development. We drew dose-response curves for Dmax and D1cc. The tolerance dose (TD) for the 5% and 50% probabilities of TLI development were 69.0 ± 1.6 and 82.1 ± 2.4 Gy for Dmax and 62.8 ± 2.2 and 80.9 ± 3.4 Gy for D1cc, respectively. The incidence of TLI in NPC patients after IMRT was higher than expected because the therapeutic window is narrow. High-quality longitudinal studies are needed to gain further insight into the complex spatiotemporal effects of non-uniform irradiation on TLI development in NPC patients. PMID:27210263

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

    SciTech Connect

    Shah, Anand; Efstathiou, Jason A.; Paly, Jonathan J.; Halpern, Scott D.; Bruner, Deborah W.; Christodouleas, John P.; Coen, John J.; Deville, Curtiland; Vapiwala, Neha; Shipley, William U.; Zietman, Anthony L.; Hahn, Stephen M.; Bekelman, Justin E.

    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.

  10. Definition and visualisation of regions of interest in post-prostatectomy image-guided intensity modulated radiotherapy

    SciTech Connect

    Bell, Linda J Cox, Jennifer; Eade, Thomas; Rinks, Marianne; Kneebone, Andrew

    2014-09-15

    Standard post-prostatectomy radiotherapy (PPRT) image verification uses bony anatomy alignment. However, the prostate bed (PB) moves independently of bony anatomy. Cone beam computed tomography (CBCT) can be used to soft tissue match, so radiation therapists (RTs) must understand pelvic anatomy and PPRT clinical target volumes (CTV). The aims of this study are to define regions of interest (ROI) to be used in soft tissue matching image guidance and determine their visibility on planning CT (PCT) and CBCT. Published CTV guidelines were used to select ROIs. The PCT scans (n = 23) and CBCT scans (n = 105) of 23 post-prostatectomy patients were reviewed. Details on ROI identification were recorded. Eighteen patients had surgical clips. All ROIs were identified on PCTs at least 90% of the time apart from mesorectal fascia (MF) (87%) due to superior image quality. When surgical clips are present, the seminal vesicle bed (SVB) was only seen in 2.3% of CBCTs and MF was unidentifiable. Most other structures were well identified on CBCT. The anterior rectal wall (ARW) was identified in 81.4% of images and penile bulb (PB) in 68.6%. In the absence of surgical clips, the MF and SVB were always identified; the ARW was identified in 89.5% of CBCTs and PB in 73.7%. Surgical clips should be used as ROIs when present to define SVB and MF. In the absence of clips, SVB, MF and ARW can be used. RTs must have a strong knowledge of soft tissue anatomy and PPRT CTV to ensure coverage and enable soft tissue matching.

  11. Definitive Upfront Stereotactic Ablative Radiotherapy Combined with Image-Guided, Intensity Modulated Radiotherapy (IG-IMRT) or IG-IMRT Alone for Locally Advanced Non-Small Cell Lung Cancer

    PubMed Central

    Chi, Alexander; Wen, Sijin; Monga, Manish; Almubarak, Mohammed; He, Xiaoqing; Rojanasakul, Yon; Tse, William; Remick, Scot C.

    2016-01-01

    Background Image-guided (IG) intensity-modulated radiotherapy (IMRT) enables maximal tumor margin reduction for the sparing of organs at risk (OARs) when used to treat locally advanced non-small cell lung cancer (NSCLC) with definitive chemo-radiation. It also allows for the incorporation of stereotactic ablative radiotherapy (SABR) into the treatment regimen. Here, we describe our initial experience in combining definitive upfront SABR to the primary lesion with chemo-radiation delivered with conventionally fractionated IG-IMRT to the remaining regional disease; along with clinical outcome following chemo-radiation with conventionally fractionated IG-IMRT alone in the treatment of locally advanced NSCLC. Methods The clinical outcome of 29 patients with locally advanced NSCLC who underwent conventionally fractionated IG-IMRT, or definitive upfront SABR followed by IG-IMRT combined with chemotherapy (induction, concurrent, or both) was retrospectively reviewed. Results After a median follow up of 23.7 months, the median overall survival (OS) and progression-free survival (PFS) were 19.8 and 11.3 months, respectively. The 2 year local, regional, and distant control was 60%, 62%, and 38%, respectively. No local failure was observed in 3 patients following SABR + IG-IMRT while 6/26 patients failed locally following IG-IMRT alone. SABR + IG-IMRT was well tolerated. No ≥ grade 3 radiation-related toxicity was observed. Conclusion Definitive upfront SABR followed by IG-IMRT in selected patients with locally advanced NSCLC warrants further investigation in future clinical trials, while chemo-radiation with IG-IMRT alone was well tolerated. PMID:27611833

  12. Changes in salivary gland function after radiotherapy of head and neck tumors measured by quantitative pertechnetate scintigraphy: Comparison of intensity-modulated radiotherapy and conventional radiation therapy with and without Amifostine

    SciTech Connect

    Muenter, Marc W. . E-mail: m.muenter@dkfz.de; Hoffner, Simone; Hof, Holger; Herfarth, Klaus K.; Haberkorn, Uwe; Rudat, Volker; Huber, Peter; Debus, Juergen; Karger, Christian P.

    2007-03-01

    Purpose: The aim of this study was to compare changes in salivary gland function after intensity-modulated radiotherapy (IMRT) and conventional radiotherapy (RT), with or without Amifostine, for tumors of the head-and-neck region using quantitative salivary gland scintigraphy (QSGS). Methods and Materials: A total of 75 patients received pre- and post-therapeutic QSGS to quantify the salivary gland function. In all, 251 salivary glands were independently evaluated. Changes in the maximum uptake ({delta}U) and relative excretion rate ({delta}F) both pre- and post-RT were determined to characterize radiation-induced changes in the salivary gland function. In addition, dose-response curves were calculated. Results: In all groups, maximum uptake and relative excretion rate were reduced after RT ({delta}U {<=}0 and {delta}F {<=}0). The reduction was significantly lower for IMRT than for conventional RT. For the parotid glands, the reduction was smaller for the IMRT-low than for the IMRT-high group. For the Amifostine-high and the conventional group the difference was significant only for one parameter ({delta}U, parotid and submandibular glands, p < 0.05). In contrast to this, the difference between the Amifostine-low and the conventional group was always significant or at least showed a clear trend for both changes in U and F. In regard to the endpoint 'reduction of the salivary gland excretion rate of more than 50%,' the dose-response curves yielded D{sub 50}-values of 34.2 {+-} 12.2 Gy for the conventionally treated group and 36.8 {+-} 2.9 Gy for the IMRT group. For the Amifostine group, an increased D{sub 50}-values of 46.3 {+-} 2.3 Gy was obtained. Conclusion: Intensity-modulated RT can significantly reduce the loss of parotid gland function when respecting a certain dose threshold. Conventional RT plus Amifostine prevents reduced salivary gland function only in the patient group treated with <40.6 Gy.

  13. Simultaneous integrated boost plan comparison of volumetric-modulated arc therapy and sliding window intensity-modulated radiotherapy for whole pelvis irradiation of locally advanced prostate cancer.

    PubMed

    Riou, Olivier; Regnault de la Mothe, Pauline; Azria, David; Aillères, Norbert; Dubois, Jean-Bernard; Fenoglietto, Pascal

    2013-07-08

    Concurrent radiotherapy to the pelvis plus a prostate boost with long-term androgen deprivation is a standard of care for locally advanced prostate cancer. IMRT has the ability to deliver highly conformal dose to the target while lowering irradiation of critical organs around the prostate. Volumetric-modulated arc therapy is able to reduce treatment time, but its impact on organ sparing is still controversial when compared to static gantry IMRT. We compared the two techniques in simultaneous integrated boost plans. Ten patients with locally advanced prostate cancer were included. The planning target volume (PTV) 1 was defined as the pelvic lymph nodes, the prostate, and the seminal vesicles plus setup margins. The PTV2 consisted of the prostate with setup margins. The prescribed doses to PTV1 and PTV2 were 54 Gy in 37 fractions and 74 Gy in 37 fractions, respectively. We compared simultaneous integrated boost plans by means of either a seven coplanar static split fields IMRT, or a one-arc (RA1) and a two-arc (RA2) RapidArc planning. All three techniques allowed acceptable homogeneity and PTV coverage. Static IMRT enabled a better homogeneity for PTV2 than RapidArc techniques. Sliding window IMRT and VMAT permitted to maintain doses to OAR within acceptable levels with a low risk of side effects for each organ. VMAT plans resulted in a clinically and statistically significant reduction in doses to bladder (mean dose IMRT: 50.1 ± 4.6Gy vs. mean dose RA2: 47.1 ± 3.9 Gy, p = 0.037), rectum (mean dose IMRT: 44± 4.5 vs. mean dose RA2: 41.6 ± 5.5 Gy, p = 0.006), and small bowel (V30 IMRT: 76.47 ± 14.91% vs. V30 RA2: 47.49 ± 16.91%, p = 0.002). Doses to femoral heads were higher with VMAT but within accepted constraints. Our findings suggest that simultaneous integrated boost plans using VMAT and sliding window IMRT allow good OAR sparing while maintaining PTV coverage within acceptable levels.

  14. Dosimetric and clinical toxicity comparison of critical organ preservation with three-dimensional conformal radiotherapy, intensity-modulated radiotherapy, and RapidArc for the treatment of locally advanced cancer of the pancreatic head

    PubMed Central

    Jin, L.; Wang, R.; Jiang, S.; Yue, J.; Liu, T.; Dou, X.; Zhu, K.; Feng, R.; Xu, X.; Chen, D.; Yin, Y.

    2016-01-01

    Purpose We compared dosimetry and clinical toxicity for 3-dimensional conformal radiotherapy (3D-crt), intensity-modulated radiotherapy (imrt), and RapidArc (Varian Medical Systems, Palo Alto, CA, U.S.A.) in locally advanced pancreatic cancer (lapcc). We hypothesized that the technique with better sparing of organs at risk (oars) and better target dose distributions could lead to decreased clinical toxicity. Methods The study analyzed 280 patients with lapcc who had undergone radiotherapy. The dosimetry comparison was performed using 20 of those patients. Dose–volume histograms for the target volume and the oars were compared. The clinical toxicity comparison used the 280 patients who received radiation with 3D-crt, imrt, or RapidArc. Results Compared with 3D-crt, RapidArc and imrt both achieved a better conformal index, homogeneity index, V95%, and V110%. Compared with 3D-crt or imrt, RapidArc reduced the V10, V20, and mean dose to duodenum, the V20 of the right kidney, and the liver mean dose. Compared with 3D-crt, RapidArc reduced the V35, and V45 of duodenum, the mean dose to small bowel, and the V15 of right kidney. The incidences of grades 3 and 4 diarrhea (p = 0.037) and anorexia (p = 0.042) were lower with RapidArc than with 3D-crt, and the incidences of grades 3 and 4 diarrhea (p = 0.027) were lower with RapidArc than with imrt. Conclusions Compared with 3D-crt or imrt, RapidArc showed better sparing of oars, especially duodenum, small bowel, and right kidney. Also, fewer acute grades 3 and 4 gastrointestinal toxicities were seen with RapidArc than with 3D-crt or imrt. A technique with better sparing of oars and better target dose distributions could result in decreased clinical toxicities during radiation treatment for lapcc. PMID:26966412

  15. SU-E-P-21: Impact of MLC Position Errors On Simultaneous Integrated Boost Intensity-Modulated Radiotherapy for Nasopharyngeal Carcinoma

    SciTech Connect

    Chengqiang, L; Yin, Y; Chen, L

    2015-06-15

    Purpose: To investigate the impact of MLC position errors on simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) for patients with nasopharyngeal carcinoma. Methods: To compare the dosimetric differences between the simulated plans and the clinical plans, ten patients with locally advanced NPC treated with SIB-IMRT were enrolled in this study. All plans were calculated with an inverse planning system (Pinnacle3, Philips Medical System{sub )}. Random errors −2mm to 2mm{sub )},shift errors{sub (} 2mm,1mm and 0.5mm) and systematic extension/ contraction errors (±2mm, ±1mm and ±0.5mm) of the MLC leaf position were introduced respectively into the original plans to create the simulated plans. Dosimetry factors were compared between the original and the simulated plans. Results: The dosimetric impact of the random and system shift errors of MLC position was insignificant within 2mm, the maximum changes in D95% of PGTV,PTV1,PTV2 were-0.92±0.51%,1.00±0.24% and 0.62±0.17%, the maximum changes in the D0.1cc of spinal cord and brainstem were 1.90±2.80% and −1.78±1.42%, the maximum changes in the Dmean of parotids were1.36±1.23% and −2.25±2.04%.However,the impact of MLC extension or contraction errors was found significant. For 2mm leaf extension errors, the average changes in D95% of PGTV,PTV1,PTV2 were 4.31±0.67%,4.29±0.65% and 4.79±0.82%, the averaged value of the D0.1cc to spinal cord and brainstem were increased by 7.39±5.25% and 6.32±2.28%,the averaged value of the mean dose to left and right parotid were increased by 12.75±2.02%,13.39±2.17% respectively. Conclusion: The dosimetric effect was insignificant for random MLC leaf position errors up to 2mm. There was a high sensitivity to dose distribution for MLC extension or contraction errors.We should pay attention to the anatomic changes in target organs and anatomical structures during the course,individual radiotherapy was recommended to ensure adaptive doses.

  16. Dosimetric Comparison Between Intensity-Modulated with Coplanar Field and 3D Conformal Radiotherapy with Noncoplanar Field for Postocular Invasion Tumor

    SciTech Connect

    Tu Wenyong; Liu Lu Zeng Jun; Yin Weidong; Li Yun

    2010-07-01

    This study presents a dosimetric optimization effort aiming to compare noncoplanar field (NCF) on 3 dimensions conformal radiotherapy (3D-CRT) and coplanar field (CF) on intensity-modulated radiotherapy (IMRT) planning for postocular invasion tumor. We performed a planning study on the computed tomography data of 8 consecutive patients with localized postocular invasion tumor. Four fields NCF 3D-CRT in the transverse plane with gantry angles of 0-10 deg., 30-45 deg., 240-270 deg., and 310-335 deg. degrees were isocentered at the center of gravity of the target volume. The geometry of the beams was determined by beam's eye view. The same constraints were prepared with between CF IMRT optimization and NCF 3D-CRT treatment. The maximum point doses (D max) for the different optic pathway structures (OPS) with NCF 3D-CRT treatment should differ in no more than 3% from those with the NCF IMRT plan. Dose-volume histograms (DVHs) were obtained for all targets and organ at risk (OAR) with both treatment techniques. Plans with NCF 3D-CRT and CF IMRT constraints on target dose in homogeneity were computed, as well as the conformity index (CI) and homogeneity index (HI) in the target volume. The PTV coverage was optimal with both NCF 3D-CRT and CF IMRT plans in the 8 tumor sites. No difference was noted between the two techniques for the average D{sub max} and D{sub min} dose. NCF 3D-CRT and CF IMRT will yield similar results on CI. However, HI was a significant difference between NCF 3D-CRT and CF IMRT plan (p < 0.001). Physical endpoints for target showed the mean target dose to be low in the CF IMRT plan, caused by a large target dose in homogeneity (p < 0.001). The impact of NCF 3D-CRT versus CF IMRT set-up is very slight. NCF3D-CRT is one of the treatment options for postocular invasion tumor. However, constraints for OARs are needed.

  17. SU-E-T-166: Evaluation of Integral Dose in Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy for Head and Neck Cancer Patient

    SciTech Connect

    Al-Basheer, A; Hunag, J; Kaminski, J; Dasher, B; Howington, J; Stewart, J; Martin, D; Kong, F; Jin, J

    2014-06-01

    Purpose: Volumetric Modulated Arc Therapy (VMAT) usually achieves higher conformity of radiation doses to targets and less delivery time than Intensity Modulated Radiation Therapy (IMRT). We hypothesized that VMAT will increase integral dose (ID) to patients which will decrease the count of white blood count (WBC) lymphocytes, and consequently has a subsequent impact on the immune system. The purpose of this study is to evaluate the ID to patients undergoing IMRT and VMAT for Head and Neck cancers and its impact on the immune system. Methods: As a pilot study, 30 head and neck patients who received 9-fields IMRT or 3-arcs Radip-Arcbased VMAT were included in this study. Ten of these patients who received the VMAT plans were re-planned using IMRT with the same objectives. ID was calculated for all cases. All patients also had a baseline WBC obtained prior to treatment, and 3 sets of labs drawn during the course of radiation treatment. Results: For the 10 re-planned patients, the mean ID was 13.3 Gy/voxel (range 10.2–17.5 Gy/voxel) for the 9-fields IMRT plans, and was 15.9 Gy/voxel (range 12.4-20.9 Gy/voxel) for the 3-Arc VMAT plan (p=0.01). The integral dose was significant correlated with reducing WBC count during RT even when controlling for concurrent chemotherapy (R square =0.56, p=0.008). Conclusion: Although VMAT can deliver higher radiation dose conformality to targets, this benefit is achieved generally at the cost of greater integral doses to normal tissue outside the planning target volume (PTV). Lower WBC counts during RT were associated with higher Integral doses even when controlling for concurrent chemotherapy. This study is ongoing in our Institution to exam the impact of integral doses and WBC on overall survival.

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

    SciTech Connect

    Peulen, Heike; Hanbeukers, Bianca; Boersma, Liesbeth; Baardwijk, Angela van; Ende, Piet van den; Houben, Ruud; Jager, Jos; Murrer, Lars; Borger, Jacques

    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.

  19. Clinical Study of the Necessity of Replanning Before the 25th Fraction During the Course of Intensity-Modulated Radiotherapy for Patients With Nasopharyngeal Carcinoma

    SciTech Connect

    Wang Wei; Yang Haihua; Hu Wei; Shan Guoping; Ding Weijun; Yu Changhui; Wang Biyun; Wang Xufeng; Xu Qianyi

    2010-06-01

    Purpose: To quantify the target and normal structures on dose distributing variations during intensity-modulated radiotherapy (IMRT) and to assess the value of replanning for nasopharyngeal carcinoma (NPC) patients. Methods and Materials: Twenty-eight NPC patients treated with IMRT were recruited. The IMRT was delivered in 33 fractions, to 70 to 76Gy, to the gross tumor volume (GTV). Before the 25th fraction of IMRT, a new simulation computed tomography (CT) scan was acquired for all patients. According to the dose constraint criterion in the Radiation Therapy Oncology Group (RTOG) 0225 protocol, the replanning was generated on the new simulation CT. With the Quality Assessment Center of a CORVUS 6.3 treatment planning system, a phantom plan was generated for each patient by applying the beam configurations of the initial plan to the anatomy of the new simulation CT. The dose-volume histograms of the phantom plan were compared with the replanning. Results: The percentage of prescription dose delivered to the clinical target volume (CTV1) was significantly increased by 4.91% +- 10.89%, whereas the maximum dose to the spinal cord, mean dose to the left parotid, and V30 to the right parotid were significantly decreased by 5.00 +- 9.23Gy, 4.23 +- 10.03Gy, and 11.47% +- 18.89% respectively in the replanning, compared with the phantom plan (p < 0.05). Based on the dose constraint criterion in the RTOG0225 protocol, 50% of phantom plans (14/28) were out of limit for the dose to the normal critical structures, whereas no plan was out of limit in replanning (p < 0.001). Conclusion: Replanning for patients with NPC before the 25th fraction during IMRT helps to ensure adequate dose to the target volumes and safe doses to critical normal structures.

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

    SciTech Connect

    Jiang Zhiqin; Yang Kunyu; Komaki, Ritsuko; Wei Xiong; Tucker, Susan L.; Zhuang Yan; Martel, Mary K.; Vedam, Sastray; Balter, Peter; Zhu Guangying; Gomez, Daniel; Lu, Charles; Mohan, Radhe; Cox, James D.; Liao Zhongxing

    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.

  1. Dosimetric Benefits of Intensity-Modulated Radiotherapy Combined With the Deep-Inspiration Breath-Hold Technique in Patients With Mediastinal Hodgkin's Lymphoma

    SciTech Connect

    Paumier, Amaury; Ghalibafian, Mithra; Gilmore, Jennifer; Beaudre, Anne; Blanchard, Pierre; El Nemr, Mohammed; Azoury, Farez; Al Hamokles, Hweej; Lefkopoulos, Dimitri; Girinsky, Theodore

    2012-03-15

    Purpose: To assess the additional benefits of using the deep-inspiration breath-hold (DIBH) technique with intensity-modulated radiotherapy (IMRT) in terms of the protection of organs at risk for patients with mediastinal Hodgkin's disease. Methods and Materials: Patients with early-stage Hodgkin's lymphoma with mediastinal involvement were entered into the study. Two simulation computed tomography scans were performed for each patient: one using the free-breathing (FB) technique and the other using the DIBH technique with a dedicated spirometer. The clinical target volume, planning target volume (PTV), and organs at risk were determined on both computed tomography scans according to the guidelines of the European Organization for Research and Treatment of Cancer. In both cases, 30 Gy in 15 fractions was prescribed. The dosimetric parameters retrieved for the statistical analysis were PTV coverage, mean heart dose, mean coronary artery dose, mean lung dose, and lung V20. Results: There were no significant differences in PTV coverage between the two techniques (FB vs. DIBH). The mean doses delivered to the coronary arteries, heart, and lungs were significantly reduced by 15% to 20% using DIBH compared with FB, and the lung V20 was reduced by almost one third. The dose reduction to organs at risk was greater for masses in the upper part of the mediastinum. IMRT with DIBH was partially implemented in 1 patient. This combination will be extended to other patients in the near future. Conclusions: Radiation exposure of the coronary arteries, heart, and lungs in patients with mediastinal Hodgkin's lymphoma was greatly reduced using DIBH with IMRT. The greatest benefit was obtained for tumors in the upper part of the mediastinum. The possibility of a wider use in clinical practice is currently under investigation in our department.

  2. Dosimetric and Clinical Outcomes of Involved-Field Intensity-Modulated Radiotherapy After Chemotherapy for Early-Stage Hodgkin's Lymphoma With Mediastinal Involvement

    SciTech Connect

    Lu Ningning; Li Yexiong; Wu Runye; Zhang Ximei; Wang Weihu; Jin Jing; Song Yongwen; Fang Hui; Ren Hua; Wang Shulian; Liu Yueping; Liu Xinfan; Chen Bo; Dai Jianrong; Yu Zihao

    2012-09-01

    Purpose: To evaluate the dosimetric and clinical outcomes of involved-field intensity-modulated radiotherapy (IF-IMRT) for patients with early-stage Hodgkin's lymphoma (HL) with mediastinal involvement. Methods and Materials: Fifty-two patients with early-stage HL that involved the mediastinum were reviewed. Eight patients had Stage I disease, and 44 patients had Stage II disease. Twenty-three patients (44%) presented with a bulky mediastinum, whereas 42 patients (81%) had involvement of both the mediastinum and either cervical or axillary nodes. All patients received combination chemotherapy followed by IF-IMRT. The prescribed radiation dose was 30-40 Gy. The dose-volume histograms of the target volume and critical normal structures were evaluated. Results: The median mean dose to the primary involved regions (planning target volume, PTV1) and boost area (PTV2) was 37.5 Gy and 42.1 Gy, respectively. Only 0.4% and 1.3% of the PTV1 and 0.1% and 0.5% of the PTV2 received less than 90% and 95% of the prescribed dose, indicating excellent PTV coverage. The median mean lung dose and V20 to the lungs were 13.8 Gy and 25.9%, respectively. The 3-year overall survival, local control, and progression-free survival rates were 100%, 97.9%, and 96%, respectively. No Grade 4 or 5 acute or late toxicities were reported. Conclusions: Despite the large target volume, IF-IMRT gave excellent dose coverage and a favorable prognosis, with mild toxicity in patients with early-stage mediastinal HL.

  3. Commissioning and quality assurance for intensity modulated radiotherapy with dynamic multileaf collimator: experience of the Pontificia Universidad Católica de Chile.

    PubMed

    Venencia, Carlos Daniel; Besa, Pelayo

    2004-01-01

    The objective of this paper is to present our experience in the commissioning and quality assurance (QA) for intensity modulated radiotherapy (IMRT) using dynamic multileaf collimator (dMLC), sliding window technique. Using Varian equipment solution, the connectivity and operation between all IMRT chain components was checked. Then the following test were done: stability of leaf positioning and leaf speed, sensitivity to treatment interruptions (acceleration and deceleration), evaluation of standard field patterns, stability of dMLC output, segmental dose accuracy check, average leaf transmission, dosimetric leaf separation, effects of lateral disequilibrium between adjacent leaves in dose profiles and multiple carriage field verification. Standard patterns were generated for verification: uniform field, pyramid, hole, wedge, peaks and chair. Weekly QA Protocol include: sweeping gap output, Garden Fence Test (narrow bands, 2 mm wide, of exposure spaced at 2-cm intervals) and segmental dose accuracy check. Monthly QA include: sweeping gap output at multiple gantry and collimator angle, sweeping gap output off-axis, Picket Fence Test (eight consecutive movements of a 5-cm wide rectangular field spaced at 5-cm intervals), stability of leaf speed and leaf motor current test (PWM test). Patient QA procedure consists of an absolute dose measurement for all treatments fields in the treatment condition, analysis of actual leaf position versus planned leaf position (dynalog files) for each treatment field, film relative dose determination for each field, film relative dose determination for the plan (all treatment fields) in two axial planes and patient positioning verification with orthogonal films. The tests performed showed acceptable result. After more than one year of IMRT treatment the routine QA machine checks confirm the precision and stability of the IMRT system.

  4. Megavoltage Cone Beam Computed Tomography Dose and the Necessity of Reoptimization for Imaging Dose-Integrated Intensity-Modulated Radiotherapy for Prostate Cancer

    SciTech Connect

    Akino, Yuichi; Koizumi, Masahiko; Sumida, Iori; Takahashi, Yutaka; Ogata, Toshiyuki; Ota, Seiichi; Isohashi, Fumiaki; Konishi, Koji; Yoshioka, Yasuo

    2012-04-01

    Purpose: Megavoltage cone beam computed tomography (MV-CBCT) dose can be integrated with the patient's prescription. Here, we investigated the effects of imaging dose and the necessity for additional optimization when using intensity-modulated radiotherapy (IMRT) to treat prostate cancer. Methods and Materials: An arc beam mimicking MV-CBCT was generated using XiO (version 4.50; Elekta, Stockholm, Sweden). The monitor units (MU) for dose calculation were determined by conforming the calculated dose to the dose measured using an ionization chamber. IMRT treatment plans of 22 patients with prostate cancer were retrospectively analyzed. Arc beams of 3, 5, 8, and 15 MU were added to the IMRT plans, and the dose covering 95% of the planning target volume (PTV) was normalized to the prescribed dose with (reoptimization) or without optimization (compensation). Results: PTV homogeneity and conformality changed negligibly with MV-CBCT integration. For critical organs, an imaging dose-dependent increase was observed for the mean rectal/bladder dose (D{sub mean}), and reoptimization effectively suppressed the D{sub mean} elevations. The bladder generalized equivalent uniform dose (gEUD) increased with imaging dose, and reoptimization suppressed the gEUD elevation when 5- to 15-MU CBCT were added, although rectal gEUD changed negligibly with any imaging dose. Whereas the dose elevation from the simple addition of the imaging dose uniformly increased rectal and bladder dose, the rectal D{sub mean} increase of compensation plans was due mainly to low-dose volumes. In contrast, bladder high-dose volumes were increased by integrating the CBCT dose, and reoptimization reduced them when 5- to 15-MU CBCT were added. Conclusion: Reoptimization is clearly beneficial for reducing dose to critical organs, elevated by addition of high-MU CBCT, especially for the bladder. For low-MU CBCT aimed at bony structure visualization, compensation is sufficient.

  5. Practical guidelines for routine intensity-modulated radiotherapy verification: pre-treatment verification with portal dosimetry and treatment verification with in vivo dosimetry

    PubMed Central

    Vinall, A J; Williams, A J; Currie, V E; Van Esch, A; Huyskens, D

    2010-01-01

    The purpose of this work is to provide guidelines for the routine use of portal dosimetry and in vivo diode measurements to verify intensity-modulated radiotherapy (IMRT) treatments. To achieve tolerance levels that are sensitive enough to intercept problems, both the portal dosimetry and the in vivo procedure must be optimised. Portal dosimetry was improved by the introduction of an optimised two-dimensional (2D) profile correction, which also accounted for the effect of backscatter from the R-arm. The scaled score, indicating the fraction of points not meeting the desired gamma evaluation criteria within the field opening, was determined as the parameter of interest. Using gamma criteria of a 3% dose difference and 3 mm distance to agreement, a “scaled score” threshold value of 1.5% was chosen to indicate excessive tongue and groove and other problems. The pre-treatment portal dosimetry quality assurance (QA) does not encompass verification of the patient dose calculation or position, and so it is complemented by in vivo diode measurements. Diode positioning is crucial in IMRT, and so we describe a method for diode positioning at any suitable point. We achieved 95% of IMRT field measurements within ±5% and 99% within ±8%, with improved accuracy being achieved over time owing to better positioning. Although the careful preparation and setup of the diode measurements can be time-consuming, this is compensated for by the time efficiency of the optimised procedure. Both methods are now easily absorbed into the routine work of the department. PMID:20965905

  6. Hypofractionated Intensity-Modulated Radiotherapy (70 Gy at 2.5 Gy Per Fraction) for Localized Prostate Cancer: Cleveland Clinic Experience

    SciTech Connect

    Kupelian, Patrick A. . E-mail: patrick.kupelian@orhs.org; Willoughby, Twyla R.; Reddy, Chandana A.; Klein, Eric A.; Mahadevan, Arul

    2007-08-01

    Purpose: To study the outcomes in patients treated for localized prostate cancer with 70 Gy delivered at 2.5-Gy/fraction within 5 weeks. Methods and Materials: The study sample included all 770 consecutive patients with localized prostate cancer treated with hypofractionated intensity-modulated radiotherapy at the Cleveland Clinic between 1998 and 2005. The median follow-up was 45 months (maximum, 86). Both American Society for Therapeutic Radiology and Oncology (ASTRO) biochemical failure definition and the alternate nadir + 2 ng/mL definition were used. Results: The overall 5-year ASTRO biochemical relapse-free survival rate was 82% (95% confidence interval, 79-85%), and the 5-year nadir + 2 ng/mL rate was 83% (95% confidence interval, 79-86%). For patients with low-risk, intermediate-risk, and high-risk disease, the 5-year ASTRO rate was 95%, 85%, and 68%, respectively. The 5-year nadir + 2 ng/mL rate for patients with low-, intermediate-, and high-risk disease was 94%, 83%, and 72%, respectively. The Radiation Therapy Oncology Group acute rectal toxicity scores were 0 in 51%, 1 in 40%, and 2 in 9% of patients. The acute urinary toxicity scores were 0 in 33%, 1 in 48%, 2 in 18%, and 3 in 1% of patients. The late rectal toxicity scores were 0 in 89.6%, 1 in 5.9%, 2 in 3.1%, 3 in 1.3%, and 4 in 0.1% (1 patient). The late urinary toxicity scores were 0 in 90.5%, 1 in 4.3%, 2 in 5.1%, and 3 in 0.1% (1 patient). Conclusion: The outcomes after high-dose hypofractionation were acceptable in the entire cohort of patients treated with the schedule of 70 at 2.5 Gy/fraction.

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

    SciTech Connect

    Setton, Jeremy; Caria, Nicola; Romanyshyn, Jonathan; Koutcher, Lawrence; Wolden, Suzanne L.; Zelefsky, Michael J.; Rowan, Nicholas; Sherman, Eric J.; Fury, Matthew G.; Pfister, David G.; Wong, Richard J.; Shah, Jatin P.; Kraus, Dennis H.; Shi Weiji; Zhang Zhigang; Schupak, Karen D.; Gelblum, Daphna Y.; Rao, Shyam D.; Lee, Nancy Y.

    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.

  8. Postoperative Intensity-Modulated Radiotherapy for Squamous Cell Carcinoma of the External Auditory Canal and Middle Ear: Treatment Outcomes, Marginal Misses, and Perspective on Target Delineation

    SciTech Connect

    Chen, Wan-Yu; Kuo, Sung-Hsin; Chen, Yu-Hsuan; Lu, Szu-Huai; Tsai, Chiao-Ling; Chia-Hsien Cheng, Jason; Hong, Ruey-Long; Chen, Ya-Fang; Hsu, Chuan-Jen; Lin, Kai-Nan; Ko, Jenq-Yuh; Lou, Pei-Jen; Wang, Cheng-Ping; Chong, Fok-Ching; Wang, Chun-Wei

    2012-03-15

    Purpose: To report outcomes of the rare disease of squamous cell carcinoma (SCC) of the external auditory canal (EAC) and middle ear treated with surgery and postoperative intensity-modulated radiotherapy (IMRT). Failure patterns related to spatial dose distribution were also analyzed to provide insight into target delineation. Methods and Materials: A retrospective review was conducted of the records of 11 consecutive patients with SCC of the EAC and middle ear who were treated with curative surgery and postoperative IMRT at one institution between January 2007 and February 2010. The prescribed IMRT dose was 60 to 66 Gy at 2 Gy per fraction. Three patients also received concurrent cisplatin-based chemotherapy, and 1 patient received concurrent oral tegafur/uracil. The median follow-up time was 19 months (range, 6-33 months). Results: Four patients had locoregional recurrence, yielding an estimated 2-year locoregional control rate of 70.7%. Among them, 1 patient had persistent disease after treatment, and 3 had marginal recurrence. Distant metastasis occurred in 1 patient after extensive locoregional recurrence, yielding an estimated 2-year distant control rate of 85.7%. The estimated 2-year overall survival was 67.5%. The three cases of marginal recurrence were near the preauricular space and glenoid fossa of the temporomandibular joint, adjacent to the apex of the ear canal and glenoid fossa of the temporomandibular joint, and in the postauricular subcutaneous area and ipsilateral parotid nodes, respectively. Conclusions: Marginal misses should be recognized to improve target delineation. When treating SCC of the EAC and middle ear, care should be taken to cover the glenoid fossa of the temporomandibular joint and periauricular soft tissue. Elective ipsilateral parotid irradiation should be considered. The treatment planning procedure should also be refined to balance subcutaneous soft-tissue dosimetry and toxicity.

  9. Should All Nasopharyngeal Carcinoma with Paranasal Sinus Invasion Be Staged as T3 in the Intensity-Modulated Radiotherapy Era? A Study of 1811 Cases

    PubMed Central

    Zhang, Yuan; Peng, Hao; Guo, Rui; Li, Wen-Fei; Chen, Lei; Liu, Xu; Tang, Ling-Long; Liu, Li-Zhi; Li, Li; Liu, Qing; Sun, Ying; Ma, Jun

    2016-01-01

    Background: Currently, there is no uniform consensus regarding the appropriate staging for invasion of the paranasal sinuses in nasopharyngeal carcinoma (NPC). In the current AJCC staging system for NPC, paranasal sinus invasion is defined within the T3 classification. However, according to the Chinese 2008 staging system, which is also widely used in the regions where NPC is endemic in China, paranasal sinus invasion is classified as T4 disease. Methods: Patients (n = 1811) with non-metastatic, histologically-proven NPC treated with intensity-modulated radiotherapy (IMRT) were retrospectively analyzed. Results: Paranasal sinus invasion was identified in 289/1811 patients (16.0%). Multivariate analysis revealed ethmoid sinus invasion (HR, 2.889; 95% CI, 1.362-6.131; P = 0.006) and maxillary sinus invasion (HR, 3.110; 95% CI, 1.439-6.721; P = 0.004) were independent prognostic factors for local relapse-free survival (LRFS). T3 patients with ethmoid sinus or maxillary sinus invasion had similar 3-year LRFS (83.6% vs. 92.2%, P = 0.132) as T4 patients, and had poorer LRFS (83.6% vs. 98.3%, P = 0.006) than T3 patients with sphenoid sinus invasion alone. Also, T3 patients with sphenoid sinus invasion alone had similar 3-year LRFS (98.3 vs. 96.4%, P = 0.391) as T3 patients without paranasal sinus invasion, and a trend toward higher LRFS (98.3% vs. 92.2%, P = 0.065) than T4 patients. Conclusion: In patients underwent IMRT, tumors with ethmoid sinus or maxillary sinus invasion had a higher risk of local failure than those with sphenoid sinus invasion alone. Sphenoid sinus invasion alone should be classified as T3 disease and ethmoid sinus or maxillary sinus involvement as T4 disease in the current AJCC staging system for NPC. PMID:27390611

  10. A phase I study of adjuvant intensity-modulated radiotherapy with concurrent paclitaxel and cisplatin for cervical cancer patients with high risk factors.

    PubMed

    Shu, Pei; Shen, Yali; Zhao, Yaqin; Xu, Feng; Qiu, Meng; Li, Qiu; Gou, Hongfeng; Cao, Dan; Yang, Yu; Liu, Jiyan; Yi, Cheng; Liao, Zhengyin; Luo, Deyun; Bi, Feng; Wang, Xin; Li, Zhiping

    2015-11-01

    The aim of the study is to determine the maximum tolerated dose (MTD) and acute dose-limiting toxicities (DLTs) of adjuvant concurrent paclitaxel and cisplatin (TP) with pelvic intensity-modulated radiotherapy (IMRT) for early-stage cervical cancer patients with high risk factors. Women who underwent radical hysterectomy and pelvic lymphadenectomy for stages IB-IIA cervical cancer and had high risk factors were enrolled. One cycle of TP was delivered before and after concurrent chemoradiotherapy, respectively. Then 3 weeks after the start of the initial cycle of the chemotherapy, patients received IMRT in a total dose of 50-50.4 Gy in 25-28 fractions with two cycles of concurrent TP, which was administered with escalating doses. Eighteen patients were enrolled at three dose levels. At dose level 1 (paclitaxel 90 mg/m(2), cisplatin 40 mg/m(2)) and level 2 (paclitaxel 90 mg/m(2), cisplatin 50 mg/m(2)), DLT (grade 3 leukopenia) was observed in one patient, respectively. At level 3 (paclitaxel 105 mg/m(2), cisplatin 50 mg/m(2)), two DLTs (grade 3 leukopenia) were observed in two patients. The MTD of paclitaxel and cisplatin was then defined as 90 and 50 mg/m(2), respectively. Pelvic IMRT and concurrent TP is a safe and tolerable adjuvant treatment regimen for cervical cancer patients with high risk factors. The MTD of concurrent chemotherapy is paclitaxel 90 mg/m(2) and cisplatin 50 mg/m(2). Trial registration Current controlled trials ChiECRCT-2014025.

  11. Neoadjuvant and Concurrent Chemotherapy Have Varied Impacts on the Prognosis of Patients with the Ascending and Descending Types of Nasopharyngeal Carcinoma Treated with Intensity-Modulated Radiotherapy

    PubMed Central

    Zhang, Wang-Jian; Lin, Li; Tang, Ling-Long; Mao, Yan-Ping; Ma, Jun; Sun, Ying

    2016-01-01

    Purpose To compare the outcomes of patients with ascending type (T4&N0-1) and descending type (T1-2&N3) of nasopharyngeal carcinoma (NPC) treated with concurrent chemoradiotherapy (CCRT), neoadjuvant chemotherapy (NACT) + intensity-modulated radiotherapy (RT) or NACT + CCRT. Methods Retrospective analysis of 839 patients with ascending or descending types of NPC treated at a single institution between October 2009 to February 2012. CCRT was delivered to 236 patients, NACT + RT to 302 patients, and NACT + CCRT to 301 patients. Results The 4-year overall survival rate, distant metastasis-free survival rate, local relapse-free survival rate, nodal relapse-free survival rate, loco-regional relapse-free survival rate, and progression free survival rate were 75.2% and 73.4% (P = 0.114), 85.7% and 74.1% (P = 0.008), 88.8% and 97.1% (P = 0.013), 96.9% and 94.1% (P = 0.122), 86.9% and 91.2% (P = 0.384), 73.7% and 66.2% (P = 0.063) in ascending type and descending type. Subgroup analyses indicated that NACT + RT significantly improved distant metastasis-free survival rate and progression-free survival rate when compared with CCRT in the ascending type, and there were no significant differences between the survival curves of NACT +RT and NACT + CCRT. For descending type, there were no significant differences among the survival curves of NACT +RT, CCRT, and NACT + CCRT groups, and the survival benefit mainly came from CCRT. Conclusions Compared with NACT + CCRT or CCRT, NACT + RT may be a reasonable approach for ascending type. Although concurrent chemotherapy was effective in descending type, NACT + CCRT may be a more appropriate strategy for descending type. PMID:27783618

  12. Proposal for the 8th Edition of the AJCC/UICC Staging System for Nasopharyngeal Cancer in the Era of Intensity-Modulated Radiotherapy

    PubMed Central

    Pan, Jian Ji; Ng, Wai Tong; Zong, Jing Feng; Chan, Lucy L. K.; O’Sullivan, Brian; Lin, Shao Jun; Sze, Henry C. K.; Chen, Yun Bin; Choi, Horace C.W.; Guo, Qiao Juan; Kan, Wai Kuen; Xiao, You Ping; Wei, Xu; Le, Quynh Thu; Glastonbury, Christine M.; Colevas, A. Dimitrios; Weber, Randal S.; Shah, Jatin P.; Lee, Anne W. M.

    2016-01-01

    BACKGROUND An accurate staging system is crucial for cancer management. Evaluations for continual suitability and improvement are needed as staging and treatment methods evolve. METHODS This was a retrospective study of 1609 patients with nasopharyngeal carcinoma investigated by magnetic resonance imaging, staged with the 7th edition of the American Joint Committee on Cancer (AJCC)/International Union Against Cancer (UICC) staging system, and irradiated by intensity-modulated radiotherapy at 2 centers in Hong Kong and mainland China. RESULTS Among the patients without other T3/T4 involvement, there were no significant differences in overall survival (OS) between medial pterygoid muscle (MP)±lateral pterygoid muscle (LP), prevertebral muscle, and parapharyngeal space involvement. Patients with extensive soft tissue involvement beyond the aforementioned structures had poor OS similar to that of patients with intracranial extension and/or cranial nerve palsy. Only 2% of the patients had lymph nodes>6cm above the supraclavicular fossa (SCF), and their outcomes resembled the outcomes of those with low extension. Replacing SCF with the lower neck (extension below the caudal border of the cricoid cartilage) did not affect the hazard distinction between different N categories. With the proposed T and N categories, there were no significant differences in outcome between T4N0-2 and T1-4N3 disease. CONCLUSIONS After a review by AJCC/UICC preparatory committees, the changes recommended for the 8th edition include changing MP/LP involvement from T4 to T2, adding prevertebral muscle involvement as T2, replacing SCF with the lower neck and merging this with a maximum nodal diameter>6 cm as N3, and merging T4 and N3 as stage IVA criteria. These changes will lead not only to a better distinction of hazards between adjacent stages/categories but also to optimal balance in clinical practicability and global applicability. PMID:26588425

  13. Intensity-Modulated Radiotherapy of Head and Neck Cancer Aiming to Reduce Dysphagia: Early Dose-Effect Relationships for the Swallowing Structures

    SciTech Connect

    Feng, Felix Y.; Kim, Hyungjin M.; Lyden, Teresa H.; Haxer, Marc J.; Feng, Mary; Worden, Frank P.; Eisbruch, Avraham . E-mail: eisbruch@umich.edu

    2007-08-01

    Purpose: To present initial results of a clinical trial of intensity-modulated radiotherapy (IMRT) aiming to spare the swallowing structures whose dysfunction after chemoradiation is a likely cause of dysphagia and aspiration, without compromising target doses. Methods and Materials: This was a prospective, longitudinal study of 36 patients with Stage III-IV oropharyngeal (31) or nasopharyngeal (5) cancer. Definitive chemo-IMRT spared salivary glands and swallowing structures: pharyngeal constrictors (PC), glottic and supraglottic larynx (GSL), and esophagus. Lateral but not medial retropharyngeal nodes were considered at risk. Dysphagia endpoints included objective swallowing dysfunction (videofluoroscopy), and both patient-reported and observer-rated scores. Correlations between doses and changes in these endpoints from pre-therapy to 3 months after therapy were assessed. Results: Significant correlations were observed between videofluoroscopy-based aspirations and the mean doses to the PC and GSL, as well as the partial volumes of these structures receiving 50-65 Gy; the highest correlations were associated with doses to the superior PC (p = 0.005). All patients with aspirations received mean PC doses >60 Gy or PC V{sub 65} >50%, and GSL V{sub 50} >50%. Reduced laryngeal elevation and epiglottic inversion were correlated with mean PC and GSL doses (p < 0.01). All 3 patients with strictures had PC V{sub 70} >50%. Worsening patient-reported liquid swallowing was correlated with mean PC (p = 0.05) and esophageal (p 0.02) doses. Only mean PC doses were correlated with worsening patient-reported solid swallowing (p = 0.04) and observer-rated swallowing scores (p = 0.04). Conclusions: These dose-volume-effect relationships provide initial IMRT optimization goals and motivate further efforts to reduce swallowing structures doses to reduce dysphagia and aspiration.

  14. Initial Evaluation of Treatment-Related Pneumonitis in Advanced-Stage Non-Small-Cell Lung Cancer Patients Treated With Concurrent Chemotherapy and Intensity-Modulated Radiotherapy

    SciTech Connect

    Yom, Sue S.; Liao Zhongxing . E-mail: zliao@mdanderson.org; Liu, H. Helen; Tucker, Susan L.; Hu, C.-S.; Wei Xiong; Wang Xuanming; Wang Shulian; Mohan, Radhe; Cox, James D.; Komaki, Ritsuko

    2007-05-01

    Purpose: To investigate the rate of high-grade treatment-related pneumonitis (TRP) in patients with advanced non-small-cell lung cancer (NSCLC) treated with concurrent chemotherapy and intensity-modulated radiotherapy (IMRT). Methods and Materials: From August 2002 to August 2005, 151 NSCLC patients were treated with IMRT. We excluded patients who did not receive concurrent chemotherapy or who had early-stage cancers, a history of major lung surgery, prior chest RT, a dose <50 Gy, or IMRT combined with three-dimensional conformal RT (3D-CRT). Toxicities were graded by Common Terminology Criteria for Adverse Events version 3.0. Grade {>=}3 TRP for 68 eligible IMRT patients was compared with TRP among 222 similar patients treated with 3D-CRT. Results: The median follow-up durations for the IMRT and 3D-CRT patients were 8 months (range, 0-27 months) and 9 months (range, 0-56 months), respectively. The median IMRT and 3D-CRT doses were 63 Gy. The median gross tumor volume was 194 mL (range, 21-911 mL) for IMRT, compared with 142 mL (range, 1.5-1,186 mL) for 3D-CRT (p = 0.002). Despite the IMRT group's larger gross tumor volume, the rate of Grade {>=}3 TRP at 12 months was 8% (95% confidence interval 4%-19%), compared with 32% (95% confidence interval 26%-40%) for 3D-CRT (p = 0.002). Conclusions: In advanced NSCLC patients treated with chemoradiation, IMRT resulted in significantly lower levels of Grade {>=}3 TRP compared with 3D-CRT. Clinical, dosimetric, and patient selection factors that may have influenced rates of TRP require continuing investigation. A randomized trial comparing IMRT with 3D-CRT has been initiated.

  15. Intensity modulated radiotherapy (IMRT) in the treatment of children and Adolescents - a single institution's experience and a review of the literature

    PubMed Central

    Sterzing, Florian; Stoiber, Eva M; Nill, Simeon; Bauer, Harald; Huber, Peter; Debus, Jürgen; Münter, Marc W

    2009-01-01

    Background While IMRT is widely used in treating complex oncological cases in adults, it is not commonly used in pediatric radiation oncology for a variety of reasons. This report evaluates our 9 year experience using stereotactic-guided, inverse planned intensity-modulated radiotherapy (IMRT) in children and adolescents in the context of the current literature. Methods Between 1999 and 2008 thirty-one children and adolescents with a mean age of 14.2 years (1.5 - 20.5) were treated with IMRT in our department. This heterogeneous group of patients consisted of 20 different tumor entities, with Ewing's sarcoma being the largest (5 patients), followed by juvenile nasopharyngeal fibroma, esthesioneuroblastoma and rhabdomyosarcoma (3 patients each). In addition a review of the available literature reporting on technology, quality, toxicity, outcome and concerns of IMRT was performed. Results With IMRT individualized dose distributions and excellent sparing of organs at risk were obtained in the most challenging cases. This was achieved at the cost of an increased volume of normal tissue receiving low radiation doses. Local control was achieved in 21 patients. 5 patients died due to progressive distant metastases. No severe acute or chronic toxicity was observed. Conclusion IMRT in the treatment of children and adolescents is feasible and was applied safely within the last 9 years at our institution. Several reports in literature show the excellent possibilities of IMRT in selective sparing of organs at risk and achieving local control. In selected cases the quality of IMRT plans increases the therapeutic ratio and outweighs the risk of potentially increased rates of secondary malignancies by the augmented low dose exposure. PMID:19775449

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

    PubMed Central

    Eiland, R.B.; Maare, C.; Sjöström, D.; Samsøe, E.; Behrens, C.F.

    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 (ReCT) and a cone beam CT (CBCT). The CBCT was acquired on the same day (±1 d) as the ReCT (i.e. at Fraction 17, 18, 23, 24 or 29). The ReCT served as ground truth. A deformed CT (dCT) with structures was created by deforming the pCT to the CBCT. The geometrical comparison was based on the volumes of the deformed, and the manually delineated structures on the ReCT. Likewise, the center of mass shift (CMS) and the Dice similarity coefficient were determined. The dosimetric comparison was performed by recalculating the initial treatment plan on the dCT and the ReCT. Dose–volume histogram (DVH) points and a range of conformity measures were used for the evaluation. We found a significant difference in the median volume of the dCT relative to that of the ReCT. Median CMS values were ∼2–5 mm, except for the spinal cord, where the median CMS was 8 mm. Dosimetric evaluation of target structures revealed small differences, while 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. PMID:24907340

  17. Weekly Dose-Volume Parameters of Mucosa and Constrictor Muscles Predict the Use of Percutaneous Endoscopic Gastrostomy During Exclusive Intensity-Modulated Radiotherapy for Oropharyngeal Cancer

    SciTech Connect

    Sanguineti, Giuseppe; Gunn, G. Brandon; Parker, Brent C.; Endres, Eugene J.; Zeng Jing; Fiorino, Claudio

    2011-01-01

    Purpose: To define predictors of percutaneous endoscopic gastrostomy (PEG) use during intensity-modulated radiotherapy (IMRT) for oropharyngeal cancer. Methods and Materials: Data for 59 consecutive patients treated with exclusive IMRT at a single institution were recovered. Of 59 patients, 25 were treated with hyperfractionation (78 Gy, 1.3 Gy per fraction, twice daily; 'HYPER'); and 34 of 59 were treated with a once-daily fractionation schedule (66 Gy, 2.2 Gy per fraction, or 70 Gy, 2 Gy per fraction; 'no-HYPER'). On the basis of symptoms during treatment, a PEG tube could have been placed as appropriate. A number of clinical/dosimetric factors, including the weekly dose-volume histogram of oral mucosa (OM DVHw) and weekly mean dose to constrictors and larynx, were considered. The OM DVHw of patients with and without PEG were compared to assess the most predictive dose-volume combinations. Results: Of 59 patients, 22 needed a PEG tube during treatment (for 15 of 22, {>=}3 months). The best cutoff values for OM DVHw were V9.5 Gy/week <64 cm{sup 3} and V10 Gy/week <54 cm{sup 3}. At univariate analysis, fractionation, mean weekly dose to OM and superior and middle constrictors, and OM DVHw were strongly correlated with the risk of PEG use. In a stepwise multivariate logistic analysis, OM V9.5 Gy/week ({>=}64 vs. <64 cm{sup 3}) was the most predictive parameter (odds ratio 30.8, 95% confidence interval 3.7-254.2, p = 0.0015), confirmed even in the no-HYPER subgroup (odds ratio 21, 95% CI 2.1 confidence interval 210.1, p = 0.01). Conclusions: The risk of PEG use is drastically reduced when OM V9.5-V10 Gy/week is <50-60 cm{sup 3}. These data warrant prospective validation.

  18. Evaluation of the dosimetric impact of applying flattening filter-free beams in intensity-modulated radiotherapy for early-stage upper thoracic carcinoma of oesophagus

    SciTech Connect

    Zhang, Wuzhe; Lin, Zhixiong; Yang, Zhining; Fang, Weisheng; Lai, Peibo; Lu, Jiayang; Wu, Vincent WC

    2015-06-15

    Flattening filter-free (FFF) radiation beams have recently become clinically available on modern linear accelerators in radiation therapy. This study aimed to evaluate the dosimetric impact of using FFF beams in intensity-modulated radiotherapy (IMRT) for early-stage upper thoracic oesophageal cancer. Eleven patients with primary stage upper thoracic oesophageal cancer were recruited. For each patient, two IMRT plans were computed using conventional beams (Con-P) and FFF beams (FFF-P), respectively. Both plans employed a five-beam arrangement and were prescribed with 64 Gy to (planning target volume) PTV1 and 54 Gy to PTV2 in 32 fractions using 6 MV photons. The dose parameters of the target volumes and organs at risks (OARs), and treatment parameters including the monitor units (MU) and treatment time (TT) for Con-P and FFF-P were recorded and compared. The mean D{sub 5} of PTV1 and PTV2 were higher in FFF-P than Con-P by 0.4 Gy and 0.3 Gy, respectively. For the OARs, all the dose parameters did not show significant difference between the two plans except the mean V{sub 5} and V{sub 10} of the lung in which the FFF-P was lower (46.7% vs. 47.3% and 39.1% vs. 39.6%, respectively). FFF-P required 54% more MU but 18.4% less irradiation time when compared to Con-P. The target volume and OARs dose distributions between the two plans were comparable. However, FFF-P was more effective in sparing the lung from low dose and reduced the mean TT compared with Con-P. Long-term clinical studies are suggested to evaluate the radiobiological effects of FFF beams.

  19. Lack of Osteoradionecrosis of the Mandible After Intensity-Modulated Radiotherapy for Head and Neck Cancer: Likely Contributions of Both Dental Care and Improved Dose Distributions

    SciTech Connect

    Ben-David, Merav A.; Diamante, Maximiliano; Vineberg, Karen A.; Stroup, Cynthia; Murdoch-Kinch, Carol-Anne . E-mail: eisbruch@med.umich.edu

    2007-06-01

    Purpose: To assess the prevalence and dosimetric and clinical predictors of mandibular osteoradionecrosis (ORN) in patients with head and neck cancer who underwent a pretherapy dental evaluation and prophylactic treatment according to a uniform policy and were treated with intensity-modulated radiotherapy (IMRT). Methods and Materials: Between 1996 and 2005, all patients with head-and-neck cancer treated with parotid gland-sparing IMRT in prospective studies underwent a dental examination and prophylactic treatment according to a uniform policy that included extractions of high-risk, periodontally involved, and nonrestorable teeth in parts of the mandible expected to receive high radiation doses, fluoride supplements, and the placement of guards aiming to reduce electron backscatter off metal teeth restorations. The IMRT plans included dose constraints for the maximal mandibular doses and reduced mean parotid gland and noninvolved oral cavity doses. A retrospective analysis of Grade 2 or worse (clinical) ORN was performed. Results: A total of 176 patients had a minimal follow-up of 6 months. Of these, 31 (17%) had undergone teeth extractions before RT and 13 (7%) after RT. Of the 176 patients, 75% and 50% had received {>=}65 Gy and {>=}70 Gy to {>=}1% of the mandibular volume, respectively. Falloff across the mandible characterized the dose distributions: the average gradient (in the axial plane containing the maximal mandibular dose) was 11 Gy (range, 1-27 Gy; median, 8 Gy). At a median follow-up of 34 months, no cases of ORN had developed (95% confidence interval, 0-2%). Conclusion: The use of a strict prophylactic dental care policy and IMRT resulted in no case of clinical ORN. In addition to the dosimetric advantages offered by IMRT, meticulous dental prophylactic care is likely an essential factor in reducing ORN risk.

  20. Validating the RTOG-Endorsed Brachial Plexus Contouring Atlas: An Evaluation of Reproducibility Among Patients Treated by Intensity-Modulated Radiotherapy for Head-and-Neck Cancer

    SciTech Connect

    Yi, Sun K.; Hall, William H.; Mathai, Mathew; Dublin, Arthur B.; Gupta, Vishal; Purdy, James A.; Chen, Allen M.

    2012-03-01

    Purpose: To evaluate interobserver variability for contouring the brachial plexus as an organ-at-risk (OAR) and to analyze its potential dosimetric consequences in patients treated with intensity-modulated radiotherapy (IMRT) for head-and-neck cancer. Methods and Materials: Using the Radiation Therapy Oncology Group (RTOG)-endorsed brachial plexus contouring atlas, three radiation oncologists independently delineated the OAR on treatment planning computed-tomography (CT) axial scans from 5 representative patients undergoing IMRT to a prescribed dose of 70 Gy for head-and-neck cancer. Dose-volume histograms for the brachial plexus were calculated, and interobserver differences were quantified by comparing various dosimetric statistics. Qualitative analysis was performed by visually assessing the overlapping contours on a single beam's eye view. Results: Brachial plexus volumes for the 5 patients across observers were 26 cc (18-35 cc), 25 cc (21-30 cc), 29 cc (28-32 cc), 29 cc (23-38 cc), and 29 cc (23-34 cc). On qualitative analysis, minimal variability existed except at the inferolateral portion of the OAR, where slight discrepancies were noted among the physicians. Maximum doses to the brachial plexus ranged from 71.6 to 72.6 Gy, 75.2 to 75.8 Gy, 69.1 to 71.0 Gy, 76.4 to 76.9 Gy, and 70.6 to 71.4 Gy. Respective volumes receiving doses greater than 60 Gy (V60) were 8.6 to 10.9 cc, 6.2 to 8.1 cc, 8.2 to 11.6 cc, 8.3 to 10.5 cc, and 5.6 to 9.8 cc. Conclusion: The RTOG-endorsed brachial plexus atlas provides a consistent set of guidelines for contouring this OAR with essentially no learning curve. Adoption of these contouring guidelines in the clinical setting is encouraged.

  1. Intensity-Modulated and 3D-Conformal Radiotherapy for Whole-Ventricular Irradiation as Compared With Conventional Whole-Brain Irradiation in the Management of Localized Central Nervous System Germ Cell Tumors

    SciTech Connect

    Chen, Michael Jenwei; Silva Santos, Adriana da; Sakuraba, Roberto Kenji; Lopes, Cleverson Perceu; Goncalves, Vinicius Demanboro; Weltman, Eduardo; Ferrigno, Robson; Cruz, Jose Carlos

    2010-02-01

    Purpose: To compare the sparing potential of cerebral hemispheres with intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3D-CRT) for whole-ventricular irradiation (WVI) and conventional whole-brain irradiation (WBI) in the management of localized central nervous system germ cell tumors (CNSGCTs). Methods and Materials: Ten cases of patients with localized CNSGCTs and submitted to WVI by use of IMRT with or without a 'boost' to the primary lesion were selected. For comparison purposes, similar treatment plans were produced by use of 3D-CRT (WVI with or without boost) and WBI (opposed lateral fields with or without boost), and cerebral hemisphere sparing was evaluated at dose levels ranging from 2 Gy to 40 Gy. Results: The median prescription dose for WVI was 30.6 Gy (range, 25.2-37.5 Gy), and that for the boost was 16.5 Gy (range, 0-23.4 Gy). Mean irradiated cerebral hemisphere volumes were lower for WVI with IMRT than for 3D-CRT and were lower for WVI with 3D-CRT than for WBI. Intensity-modulated radiotherapy was associated with the lowest irradiated volumes, with reductions of 7.5%, 12.2%, and 9.0% at dose levels of 20, 30, and 40 Gy, respectively, compared with 3D-CRT. Intensity-modulated radiotherapy provided statistically significant reductions of median irradiated volumes at all dose levels (p = 0.002 or less). However, estimated radiation doses to peripheral areas of the body were 1.9 times higher with IMRT than with 3D-CRT. Conclusions: Although IMRT is associated with increased radiation doses to peripheral areas of the body, its use can spare a significant amount of normal central nervous system tissue compared with 3D-CRT or WBI in the setting of CNSGCT treatment.

  2. Is intensity-modulated radiotherapy better than conventional radiation treatment and three-dimensional conformal radiotherapy for mediastinal masses in patients with Hodgkin's disease, and is there a role for beam orientation optimization and dose constraints assigned to virtual volumes?

    SciTech Connect

    Girinsky, Theodore . E-mail: girinsky@igr.fr; Pichenot, Charlotte; Beaudre, Anne; Ghalibafian, Mithra; Lefkopoulos, Dimitri

    2006-01-01

    Purpose: To evaluate the role of beam orientation optimization and the role of virtual volumes (VVs) aimed at protecting adjacent organs at risk (OARs), and to compare various intensity-modulated radiotherapy (IMRT) setups with conventional treatment with anterior and posterior fields and three-dimensional conformal radiotherapy (3D-CRT). Methods and Materials: Patients with mediastinal masses in Hodgkin's disease were treated with combined modality therapy (three to six cycles of adriamycin, bleomycin, vinblastine, and dacarbazine [ABVD] before radiation treatment). Contouring and treatment planning were performed with Somavision and CadPlan Helios (Varian Systems, Palo Alto, CA). The gross tumor volume was determined according to the prechemotherapy length and the postchemotherapy width of the mediastinal tumor mass. A 10-mm isotropic margin was added for the planning target volume (PTV). Because dose constraints assigned to OARs led to unsatisfactory PTV coverage, VVs were designed for each patient to protect adjacent OARs. The prescribed dose was 40 Gy to the PTV, delivered according to guidelines from International Commission on Radiation Units and Measurements Report No. 50. Five different IMRT treatment plans were compared with conventional treatment and 3D-CRT. Results: Beam orientation was important with respect to the amount of irradiated normal tissues. The best compromise in terms of PTV coverage and protection of normal tissues was obtained with five equally spaced beams (5FEQ IMRT plan) using dose constraints assigned to VVs. When IMRT treatment plans were compared with conventional treatment and 3D-CRT, dose conformation with IMRT was significantly better, with greater protection of the heart, coronary arteries, esophagus, and spinal cord. The lungs and breasts in women received a slightly higher radiation dose with IMRT compared with conventional treatments. The greater volume of normal tissue receiving low radiation doses could be a cause for

  3. SU-E-T-417: The Impact of Normal Tissue Constraints On PTV Dose Homogeneity for Intensity Modulated Radiotherapy (IMRT), Volume Modulated Arc Therapy (VMAT) and Tomotherapy

    SciTech Connect

    Peng, J; McDonald, D; Ashenafi, M; Ellis, A; Vanek, K

    2014-06-01

    Purpose: Complex intensity modulated arc therapy tends to spread low dose to normal tissue(NT)regions to obtain improved target conformity and homogeneity and OAR sparing.This work evaluates the trade-offs between PTV homogeneity and reduction of the maximum dose(Dmax)spread to NT while planning of IMRT,VMAT and Tomotherapy. Methods: Ten prostate patients,previously planned with step-and-shoot IMRT,were selected.To fairly evaluate how PTV homogeneity was affected by NT Dmax constraints,original IMRT DVH objectives for PTV and OARs(femoral heads,and rectal and bladder wall)applied to 2 VMAT plans in Pinnacle(V9.0), and Tomotherapy(V4.2).The only constraint difference was the NT which was defined as body contours excluding targets,OARs and dose rings.NT Dmax constraint for 1st VMAT was set to the prescription dose(Dp).For 2nd VMAT(VMAT-NT)and Tomotherapy,it was set to the Dmax achieved in IMRT(~70-80% of Dp).All NT constraints were set to the lowest priority.Three common homogeneity indices(HI),RTOG-HI=Dmax/Dp,moderated-HI=D95%/D5% and complex-HI=(D2%-D98%)/Dp*100 were calculated. Results: All modalities with similar dosimetric endpoints for PTV and OARs.The complex-HI shows the most variability of indices,with average values of 5.9,4.9,9.3 and 6.1 for IMRT,VMAT,VMAT-NT and Tomotherapy,respectively.VMAT provided the best PTV homogeneity without compromising any OAR/NT sparing.Both VMAT-NT and Tomotherapy,planned with more restrictive NT constraints,showed reduced homogeneity,with VMAT-NT showing the worst homogeneity(P<0.0001)for all HI.Tomotherapy gave the lowest NT Dmax,with slightly decreased homogeneity compared to VMAT. Finally, there was no significant difference in NT Dmax or Dmean between VMAT and VMAT-NT. Conclusion: PTV HI is highly dependent on permitted NT constraints. Results demonstrated that VMAT-NT with more restrictive NT constraints does not reduce Dmax NT,but significantly receives higher Dmax and worse target homogeneity.Therefore, it is critical

  4. First Clinical Release of an Online, Adaptive, Aperture-Based Image-Guided Radiotherapy Strategy in Intensity-Modulated Radiotherapy to Correct for Inter- and Intrafractional Rotations of the Prostate

    SciTech Connect

    Deutschmann, Heinz; Kametriser, Gerhard; Steininger, Philipp; Scherer, Philipp; Schoeller, Helmut; Gaisberger, Christoph; Mooslechner, Michaela; Mitterlechner, Bernhard; Weichenberger, Harald; Fastner, Gert; Wurstbauer, Karl; Jeschke, Stephan; Forstner, Rosemarie; Sedlmayer, Felix

    2012-08-01

    Purpose: We developed and evaluated a correction strategy for prostate rotations using direct adaptation of segments in intensity-modulated radiotherapy (IMRT). Method and Materials: Implanted fiducials (four gold markers) were used to determine interfractional translations, rotations, and dilations of the prostate. We used hybrid imaging: The markers were automatically detected in two pretreatment planar X-ray projections; their actual position in three-dimensional space was reconstructed from these images at first. The structure set comprising prostate, seminal vesicles, and adjacent rectum wall was transformed accordingly in 6 degrees of freedom. Shapes of IMRT segments were geometrically adapted in a class solution forward-planning approach, derived within seconds on-site and treated immediately. Intrafractional movements were followed in MV electronic portal images captured on the fly. Results: In 31 of 39 patients, for 833 of 1013 fractions (supine, flat couch, knee support, comfortably full bladder, empty rectum, no intraprostatic marker migrations >2 mm of more than one marker), the online aperture adaptation allowed safe reduction of margins clinical target volume-planning target volume (prostate) down to 5 mm when only interfractional corrections were applied: Dominant L-R rotations were found to be 5.3 Degree-Sign (mean of means), standard deviation of means {+-}4.9 Degree-Sign , maximum at 30.7 Degree-Sign . Three-dimensional vector translations relative to skin markings were 9.3 {+-} 4.4 mm (maximum, 23.6 mm). Intrafractional movements in 7.7 {+-} 1.5 min (maximum, 15.1 min) between kV imaging and last beam's electronic portal images showed further L-R rotations of 2.5 Degree-Sign {+-} 2.3 Degree-Sign (maximum, 26.9 Degree-Sign ), and three-dimensional vector translations of 3.0 {+-}3.7 mm (maximum, 10.2 mm). Addressing intrafractional errors could further reduce margins to 3 mm. Conclusion: We demonstrated the clinical feasibility of an online

  5. Protocol for a phase III randomised trial of image-guided intensity modulated radiotherapy (IG-IMRT) and conventional radiotherapy for late small bowel toxicity reduction after postoperative adjuvant radiation in Ca cervix

    PubMed Central

    Chopra, Supriya; Engineer, Reena; Mahantshetty, Umesh; Misra, Shagun; Phurailatpam, Reena; Paul, Siji N; Kannan, Sadhna; Kerkar, Rajendra; Maheshwari, Amita; Shylasree, TS; Ghosh, Jaya; Gupta, Sudeep; Thomas, Biji; Singh, Shalini; Sharma, Sanjiv; Chilikuri, Srinivas; Shrivastava, Shyam Kishore

    2012-01-01

    Introduction External beam radiation followed by vaginal brachytherapy (±chemotherapy) leads to reduction in the risk of local recurrence and improves progression-free survival in patients with adverse risk factors following Wertheim's hysterectomy albeit at the risk of late bowel toxicity. Intensity Modulated Radiotherapy (IMRT) results in reduction in bowel doses and has potential to reduce late morbidity, however, needs to be confirmed prospectively in a randomised trial. The present randomised trial tests reduction if any in late small bowel toxicity with the use of IMRT in postoperative setting. Methods and analysis Patients more than 18 years of age who need adjuvant (chemo) radiation will be eligible. Patients with residual pelvic or para-aortic nodal disease, history of multiple abdominal surgeries or any other medical bowel condition will be excluded. The trial will randomise patients into standard radiation or IMRT. The primary aim is to compare differences in late grades II–IV bowel toxicity between the two arms. The secondary aims of the study focus on evaluating correlation of dose–volume parameters and late toxicity and quality of life. The trial is planned as a multicentre randomised study. The trial is designed to detect a 13% difference in late grades II–IV bowel toxicity with an α of 0.05 and β of 0.80. A total of 240 patients will be required to demonstrate the aforesaid difference. Ethics and dissemination The trial is approved by institutional ethics review board and will be routinely monitored as per standard guidelines. The study results will be disseminated via peer reviewed scientific journals, conference presentations and submission to regulatory authorities. Registration The trial is registered with clinicaltrials.gov (NCT 01279135). PMID:23242243

  6. Peripheral dose measurements with diode and thermoluminescence dosimeters for intensity modulated radiotherapy delivered with conventional and un-conventional linear accelerator.

    PubMed

    Kinhikar, Rajesh; Gamre, Poonam; Tambe, Chandrashekhar; Kadam, Sudarshan; Biju, George; Suryaprakash; Magai, C S; Dhote, Dipak; Shrivastava, Shyam; Deshpande, Deepak

    2013-01-01

    The objective of this paper was to measure the peripheral dose (PD) with diode and thermoluminescence dosimeter (TLD) for intensity modulated radiotherapy (IMRT) with linear accelerator (conventional LINAC), and tomotherapy (novel LINAC). Ten patients each were selected from Trilogy dual-energy and from Hi-Art II tomotherapy. Two diodes were kept at 20 and 25 cm from treatment field edge. TLDs (LiF:MgTi) were also kept at same distance. TLDs were also kept at 5, 10, and 15 cm from field edge. The TLDs were read with REXON reader. The readings at the respective distance were recorded for both diode and TLD. The PD was estimated by taking the ratio of measured dose at the particular distance to the prescription dose. PD was then compared with diode and TLD for LINAC and tomotherapy. Mean PD for LINAC with TLD and diode was 2.52 cGy (SD 0.69), 2.07 cGy (SD 0.88) at 20 cm, respectively, while at 25 cm, it was 1.94 cGy (SD 0.58) and 1.5 cGy (SD 0.75), respectively. Mean PD for tomotherapy with TLD and diode was 1.681 cGy SD 0.53) and 1.58 (SD 0.44) at 20 cm, respectively. The PD was 1.24 cGy (SD 0.42) and 1.088 cGy (SD 0.35) at 25 cm, respectively, for tomotherapy. Overall, PD from tomotherapy was found lower than LINAC by the factor of 1.2-1.5. PD measurement is essential to find out the potential of secondary cancer. PD for both (conventional LINAC) and novel LINACs (tomotherapy) were measured and compared with each other. The comparison of the values for PD presented in this work and those published in the literature is difficult because of the different experimental conditions. The diode and TLD readings were reproducible and both the detector readings were comparable.

  7. Dosimetric comparison between intensity-modulated radiotherapy and RapidArc with single arc and dual arc for malignant glioma involving the parietal lobe

    PubMed Central

    YUAN, JUN; LEI, MINGJUN; YANG, ZHEN; FU, JUN; HUO, LEI; HONG, JIDONG

    2016-01-01

    The aim of the present study was to evaluate the difference in treatment plan quality, monitor units (MUs) per fraction and dosimetric parameters between IMRT (intensity-modulated radiotherapy) and RapidArc with single arc (RA1) and dual arc (RA2) for malignant glioma involving the parietal lobe. Treatment plans for IMRT and RA1 and RA2 were prepared for 10 patients with malignant gliomas involving the parietal lobe. The Wilcoxon matched-pair signed-rank test was used to compare the plan quality, monitor units and dosimetric parameters between IMRT and RA1 and RA2 through dose-volume histograms. Dnear-max (D2%) to the left lens, right lens and left optical nerve in RA1 were less compared with those in IMRT; D2% to the right lens and right optic nerve in RA2 were less compared with those in IMRT. D2% to the optic chiasma in RA2 was small compared with that in RA1. The median dose (D50%) to the right lens and right optic nerve in RA1 and RA2 was less compared with the identical parameters in IMRT, and D50% to the brain stem in RA2 was less compared with that in RA1. The volume receiving at least 45 Gy (V45) or V50 in normal brain tissue (whole brain minus the planning target volume 2; B-P) in RA1 was less compared with that in IMRT. V30, V35, V40, V45, or V50 in B-P in RA2 was less compared with that in IMRT. The MUs per fraction in RA1 and RA2 were significantly less compared with those in IMRT. All differences with a P-value<0.05 were considered to be significantly different. In conclusion, RA1 and RA2 markedly reduced the MUs per fraction, and spared partial organs at risk and B-P compared with IMRT. PMID:27330795

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

    SciTech Connect

    Liu, D; Chi, Z; Yang, H; Miao, M; Jing, Z

    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.

  9. [Accelerated partial breast irradiation with image-guided intensity-modulated radiotherapy following breast-conserving surgery - preliminary results of a phase II clinical study].

    PubMed

    Mészáros, Norbert; Major, Tibor; Stelczer, Gábor; Zaka, Zoltán; Mózsa, Emõke; Fodor, János; Polgár, Csaba

    2015-06-01

    The purpose of the study was to implement accelerated partial breast irradiation (APBI) by means of image-guided intensity-modulated radiotherapy (IG-IMRT) following breast-conserving surgery (BCS) for low-risk early invasive breast cancer. Between July 2011 and March 2014, 60 patients with low-risk early invasive (St I-II) breast cancer who underwent BCS were enrolled in our phase II prospective study. Postoperative APBI was given by means of step and shoot IG-IMRT using 4 to 5 fields to a total dose of 36.9 Gy (9×4.1 Gy) using a twice-a-day fractionation. Before each fraction, series of CT images were taken from the region of the target volume using a kV CT on-rail mounted in the treatment room. An image fusion software was used for automatic image registration of the planning and verification CT images. Patient set-up errors were detected in three directions (LAT, LONG, VERT), and inaccuracies were adjusted by automatic movements of the treatment table. Breast cancer related events, acute and late toxicities, and cosmetic results were registered and analysed. At a median follow-up of 24 months (range 12-44) neither locoregional nor distant failure was observed. Grade 1 (G1), G2 erythema, G1 oedema, and G1 and G2 pain occurred in 21 (35%), 2 (3.3%), 23 (38.3%), 6 (10%) and 2 (3.3%) patients, respectively. No G3-4 acute side effects were detected. Among late radiation side effects G1 pigmentation, G1 fibrosis, and G1 fat necrosis occurred in 5 (8.3%), 7 (11.7%), and 2 (3.3%) patients, respectively. No ≥G2 late toxicity was detected. Excellent and good cosmetic outcome was detected in 45 (75%) and 15 (25%) patients. IG-IMRT is a reproducible and feasible technique for the delivery of APBI following conservative surgery for the treatment of low-risk, early-stage invasive breast carcinoma. Preliminary results are promising, early radiation side effects are minimal, and cosmetic results are excellent. PMID:26035158

  10. SU-E-J-116: Uncertainties Associated with Dose Summation of High-Dose Rate Brachytherapy and Intensity Modulated Radiotherapy for Gynecological Cases

    SciTech Connect

    Kauweloa, K; Bergamo, A; Gutierrez, A; Stathakis, S; Papanikolaou, N; Kirby, N; Mavroidis, P

    2015-06-15

    Purpose: Determining the cumulative dose distribution (CDD) for gynecological patients treated with both high-dose rate (HDR) brachytherapy and intensity-modulated radiotherapy (IMRT) is challenging. The purpose of this work is to study the uncertainty of performing this with a structure-guided deformable (SGD) approach in Velocity. Methods: For SGD, the Hounsfield units inside specified contours are overridden to set uniform values. Deformable image registration (DIR) is the run on these process images, which forces the DIR to focus on these contour boundaries. 18 gynecological cancer patients were used in this study. The original bladder and rectum planning contours for these patients were used to drive the SGD. A second set of contours were made of the bladder by the same person with the intent of carefully making them completely consistent with each other. This second set was utilized to evaluate the spatial accuracy of the SGD. The determined spatial accuracy was then multiplied by the local dose gradient to determine a dose uncertainty associated with the SGD dose warping. The normal tissue complication probability (NTCP) was then calculated for each dose volume histogram (DVH) that included four different probabilistic uncertainties associated with the spatial errors (e.g., 68.3% and 95.4%). Results: The NTCPs for each DVH (e.g., NTCP-−95.4%, NTCP-−68.3%, NTCP-68.3%, NTCP-95.4%) differed amongst patients. All patients had an NTCP-−95.4% close to 0%, while NTCP-95.4% ranged from 0.67% to 100%. Nine patients had an NTCP-−95.4% less than 50% while the remaining nine patients had NTCP-95.4% greater than 50%. Conclusion: The uncertainty associated with this CDD technique renders a large NTCP uncertainty. Thus, it is currently not practical for clinical use. The two ways to improve this would be to use more precise contours to drive the SGD and to use a more accurate DIR algorithm.

  11. Effect of intrafractional prostate motion on simultaneous boost intensity-modulated radiotherapy to the prostate: a simulation study based on intrafractional motion in the prone position.

    PubMed

    Ikeda, Itaru; Mizowaki, Takashi; Ono, Tomohiro; Yamada, Masahiro; Nakamura, Mitsuhiro; Monzen, Hajime; Yano, Shinsuke; Hiraoka, Masahiro

    2015-01-01

    Although the prostate displacement of patients in the prone position is affected by respiration-induced motion, the effect of intrafractional prostate motion in the prone position during "simultaneous integrated boost intensity-modulated radiotherapy" (SIB-IMRT) is unclear. The purpose of this study was to evaluate the dosimetric effects of intrafractional motion on SIB-IMRT to a dominant intraprostatic lesion (IPL) using measured motion data of patients in a prone position, fixed with a thermoplastic shell. We obtained 2 orthogonal x-ray fluoroscopic images at the same moment every 0.2 seconds for 30 seconds before and after treatment, once weekly, from 7 patients with localized prostate cancer with detectable prostatic calcification. Prostate displacements in the left-right (LR), anteroposterior (AP), and superoinferior (SI) directions were calculated using the prostatic calcification as a fiducial marker. We defined the displacement between pretreatment and posttreatment as baseline drift (BD). An SIB-IMRT plan was generated in which each IPL + 3mm received a dose of 94.5Gy, whereas the remainder of the prostate + 7mm received a dose of 75.6Gy in 9 fields. A simulated plan of dose blurring was generated by the convolution of isocenter-shifted plans using measured motion data in 30 seconds and motion in 30 seconds + distance between pretreatment and posttreatment position (BD) for each of the 7 patients. The motion in 30 seconds mainly reflected respiration-induced motion. The mean displacements of BD were 1.4mm (- 3.1 to 8.2mm), - 2.2mm (- 9.1 to 1.5mm), and - 0.3mm (- 5.0 to 1.8mm) in the AP, SI, and LR directions, respectively. The differences in the target coverage with V90% of the IPL and V100% of the prostate between the simulated plan and original plan were - 3.9% to - 0.3% and - 0.6% to 1.1% for respiration-induced motion and 3.1% to - 67.8% and 3.6% to - 13.3% for BD with respiration-induced motion, respectively. The large motion of BD resulted in an

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

    SciTech Connect

    Miah, Aisha B.; Bhide, Shreerang A.; Guerrero-Urbano, M. Teresa; Clark, Catharine; Bidmead, A. Margaret; St Rose, Suzanne; Barbachano, Yolanda; A'Hern, Roger; Tanay, Mary; Hickey, Jennifer; Nicol, Robyn; Newbold, Kate L.; Harrington, Kevin J.; Nutting, Christopher M.

    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

  13. No Impairment of Quality of Life 18 Months After High-Dose Intensity-Modulated Radiotherapy for Localized Prostate Cancer: A Prospective Study

    SciTech Connect

    Marchand, Virginie; Bourdin, Sylvain; Charbonnel, Christelle; Rio, Emmanuel

    2010-07-15

    Purpose: To determine prospectively intermediate-term toxicity and quality of life (QoL) of prostate cancer patients after intensity-modulated radiotherapy (IMRT). Patients and Methods: Fifty-five patients with localized prostate adenocarcinoma were treated by IMRT (76 Gy). Physicians scored acute and late toxicity using the Common Terminology Criteria for Adverse Events version 3.0. Patients assessed general and prostate-specific QoL before IMRT (baseline) and at 2, 6, and 18 months using European Organization for Research and Treatment of Cancer questionnaires QLQ-C30(+3) and QLQ-PR25. Results: Median age was 73 years (range, 54-80 years). Risk categories were 18% low risk, 60% intermediate risk, and 22% high risk; 45% of patients received hormonal therapy (median duration, 6 months). The incidence of urinary and bowel toxicity immediately after IMRT was, respectively, 38% and 13% (Grade 2) and 2% and none (Grade 3); at 18 months it was 15% and 11% (Grade 2) and none (Grade 3). Significant worsening of QoL was reported at 2 months with regard to fatigue (+11.31, p = 1.10{sup -7}), urinary symptoms (+9.07, p = 3.10{sup -11}), dyspnea (+7.27, p = 0.008), and emotional (-7.02, p = 0.002), social (-6.36, p = 0.003), cognitive (-4.85, p = 0.004), and physical (-3.39, p = 0.007) functioning. Only fatigue (+5.86, p = 0.003) and urinary symptoms (+5.86, p = 0.0004) had not improved by 6 months. By 18 months all QoL scores except those for dyspnea (+8.02, p = 0.01) and treatment-related symptoms (+4.24, p = 0.01) had returned to baseline. These adverse effects were exacerbated by hormonal therapy. Conclusion: High-dose IMRT with accurate positioning induces only a temporary worsening of QoL.

  14. Anterior Myocardial Territory May Replace the Heart as Organ at Risk in Intensity-Modulated Radiotherapy for Left-Sided Breast Cancer

    SciTech Connect

    Tan Wenyong; Liu Dong; Xue Chenbin; Xu Jiaozhen; Li Beihui; Chen Zhengwang; Hu Desheng; Wang Xionghong

    2012-04-01

    Purpose: We investigated whether the heart could be replaced by the anterior myocardial territory (AMT) as the organ at risk (OAR) in intensity-modulated radiotherapy (IMRT) of the breast for patients with left-sided breast cancer. Methods and Materials: Twenty-three patients with left-sided breast cancer who received postoperative radiation after breast-conserving surgery were studied. For each patient, we generated five IMRT plans including heart (H), left ventricle (LV), AMT, LV+AMT, and H+LV as the primary OARs, respectively, except both lungs and right breast, which corresponded to IMRT(H), IMRT(LV), IMRT(AMT), IMRT(LV+AMT), and IMRT(H+LV). For the planning target volumes and OARs, the parameters of dose-volume histograms were compared. Results: The homogeneity index, conformity index, and coverage index were not compromised significantly in IMRT(AMT), IMRT(LV) and IMRT(LV+ AMT), respectively, when compared with IMRT(H). The mean dose to the heart, LV, and AMT decreased 5.3-21.5% (p < 0.05), 19.9-29.5% (p < 0.05), and 13.3-24.5% (p < 0.05), respectively. Similarly, the low (e.g., V5%), middle (e.g., V20%), and high (e.g., V30%) dose-volume of the heart, LV, and AMT decreased with different levels. The mean dose and V10% of the right lung increased by 9.2% (p < 0.05) and 27.6% (p < 0.05), respectively, in IMRT(LV), and the mean dose and V5% of the right breast decreased significantly in IMRT(AMT) and IMRT(LV+AMT). IMRT(AMT) was the preferred plan and was then compared with IMRT(H+LV); the majority of dose-volume histogram parameters of OARs including the heart, LV, AMT, both lungs, and the right breast were not statistically different. However, the low dose-volume of LV increased and the middle dose-volume decreased significantly (p < 0.05) in IMRT(AMT). Also, those of the right lung (V10%, V15%) and right breast (V5%, V10%) decreased significantly (p < 0.05). Conclusions: The AMT may replace the heart as the OAR in left-sided breast IMRT after breast

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

    SciTech Connect

    Qiu, R; Wang, Y; Cao, Y; Zhang, R; Shang, K; Chi, Z

    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

  16. Potential for reduced radiation-induced toxicity using intensity-modulated arc therapy for whole-brain radiotherapy with hippocampal sparing.

    PubMed

    Pokhrel, Damodar; Sood, Sumit; Lominska, Christopher; Kumar, Pravesh; Badkul, Rajeev; Jiang, Hongyu; Wang, Fen

    2015-01-01

    The purpose of this study was to retrospectively investigate the accuracy, plan quality, and efficiency of using intensity-modulated arc therapy (IMAT) for whole brain radiotherapy (WBRT) patients with sparing not only the hippocampus (following RTOG 0933 compliance criteria) but also other organs at risk (OARs). A total of 10 patients previously treated with nonconformal opposed laterals whole-brain radiotherapy (NC-WBRT) were retrospectively replanned for hippocampal sparing using IMAT treatment planning. The hippocampus was volumetrically contoured on fused diagnostic T1-weighted MRI with planning CT images and hippocampus avoidance zone (HAZ) was generated using a 5 mm uniform margin around the hippocampus. Both hippocampi were defined as one paired organ. Whole brain tissue minus HAZ was defined as the whole-brain planning target volume (WB-PTV). Highly conformal IMAT plans were generated in the Eclipse treatment planning system for Novalis TX linear accelerator consisting of high-definition multileaf collimators (HD-MLCs: 2.5 mm leaf width at isocenter) and 6 MV beam for a prescription dose of 30 Gy in 10 fractions following RTOG 0933 dosimetric criteria. Two full coplanar arcs with orbits avoidance sectors were used. In addition to RTOG criteria, doses to other organs at risk (OARs), such as parotid glands, cochlea, external/middle ear canals, skin, scalp, optic pathways, brainstem, and eyes/lens, were also evaluated. Subsequently, dose delivery efficiency and accuracy of each IMAT plan was assessed by delivering quality assurance (QA) plans with a MapCHECK device, recording actual beam-on time and measuring planed vs. measured dose agreement using a gamma index. On IMAT plans, following RTOG 0933 dosimetric criteria, the maximum dose to WB-PTV, mean WB-PTV D2%, and mean WB-PTV D98% were 34.9 ± 0.3 Gy, 33.2 ± 0.4 Gy, and 26.0± 0.4Gy, respectively. Accordingly, WB-PTV received the prescription dose of 30Gy and mean V30 was 90.5% ± 0.5%. The D100%, and

  17. A comparative dosimetric study of volumetric-modulated arc therapy vs. fixed field intensity-modulated radiotherapy in postoperative irradiation of stage IB-IIA high-risk cervical cancer

    PubMed Central

    QIAO, LILI; CHENG, JIAN; LIANG, NING; XIE, JIAN; LUO, HUI; ZHANG, JIANDONG

    2016-01-01

    The aim of the present study was to compare the dosimetry features of volumetric-modulated arc therapy (VMAT) and fixed field intensity-modulated radiotherapy (f-IMRT) in postoperative irradiation of stage IB-IIA high-risk cervical cancer. Fifteen patients exhibiting stage IB-IIA high-risk cervical cancer, who had been treated with postoperative adjuvant concurrent radiochemotherapy, were selected. The clinical target volume (CTV) and organs at risk (OARs) were delineated according to contrast computed tomography images. The planning target volume (PTV) was subsequently produced by using 1 cm uniform expansion of the CTV. The treatment plans were intended to deliver 50 Gy in 25 fractions. The OARs that were contoured included the bladder, rectum, small bowel and femoral heads. Dose volume histograms were used to evaluate the dose distribution in the PTV and OARs. VMAT and f-IMRT treatment plans resulted in similar dose coverage of the PTV. VMAT was superior to f-IMRT in conformity (P<0.05), and resulted in a reduction of OARs irradiated at high dose levels (V40 and V50) compared with f-IMRT (P<0.05), particularly for the bladder. However, the doses of low levels (V10 and V20) delivered to OARs with f-IMRT were slightly reduced compared with VMAT (P<0.05). For ambilateral femoral heads, VMAT demonstrated improved sparing compared with f-IMRT, with regard to D5 (P<0.05). Furthermore, VMAT treatment plans revealed a significant reduction in monitor units (MU) and treatment time. VMAT techniques exhibited similar PTV coverage compared with f-IMRT. At doses of high levels delivered to OARs, VMAT demonstrated improved sparing compared with f-IMRT, particularly for the bladder, while significantly reducing treatment time and MU number. PMID:26893675

  18. A comparison of volumetric modulated arc therapy and sliding-window intensity-modulated radiotherapy in the treatment of Stage I-II nasal natural killer/T-cell lymphoma.

    PubMed

    Liu, Xianfeng; Yang, Yong; Jin, Fu; He, Yanan; Zhong, Mingsong; Luo, Huanli; Qiu, Da; Li, Chao; Yang, Han; He, Guanglei; Wang, Ying

    2016-01-01

    This article is aimed to compare the dosimetric differences between volumetric modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) for Stage I-II nasal natural killer/T-cell lymphoma (NNKTL). Ten patients with Stage I-II NNKTL treated with IMRT were replanned with VMAT (2 arcs). The prescribed dose of the planning target volume (PTV) was 50Gy in 25 fractions. The VMAT plans with the Anisotropic Analytical Algorithm (Version 8.6.15) were based on an Eclipse treatment planning system; the monitor units (MUs) and treatment time (T) were scored to measure the expected treatment efficiency. All the 10 patients under the study were subject to comparisons regarding the quality of target coverage, the efficiency of delivery, and the exposure of normal adjacent organs at risk (OARs). The study shows that VMAT was associated with a better conformal index (CI) and homogeneity index (HI) (both p < 0.05) but slightly higher dose to OARs than IMRT. The MUs with VMAT (650.80 ± 24.59) were fewer than with IMRT (1300.10 ± 57.12) (relative reduction of 49.94%, p = 0.00) when using 2-Gy dose fractions. The treatment time with VMAT (3.20 ± 0.02 minutes) was shorter than with IMRT (7.38 ± 0.18 minutes) (relative reduction of 56.64%, p = 0.00). We found that VMAT and IMRT both provide satisfactory target dosimetric coverage and OARs sparing clinically. Likely to deliver a bit higher dose to OARs, VMAT in comparison with IMRT, is still a better choice for treatment of patients with Stage I-II NNKTL, thanks to better dose distribution, fewer MUs, and shorter delivery time. PMID:26428072

  19. 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)

    PubMed Central

    2011-01-01

    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 < 0.05, respectively). The PA-VMAT technique improves the dose sparing (V20, 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 < 0.05 and for treatment time: mean 13.7 vs. 10.6 vs. 6.4 minutes, p < 0.01). 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. PMID:22014217

  20. Involved-Node and Involved-Field Volumetric Modulated Arc vs. Fixed Beam Intensity-Modulated Radiotherapy for Female Patients With Early-Stage Supra-Diaphragmatic Hodgkin Lymphoma: A Comparative Planning Study

    SciTech Connect

    Weber, Damien C.; Peguret, Nicolas; Dipasquale, Giovanna; Cozzi, Luca

    2009-12-01

    Purpose: A comparative treatment planning study was performed to compare volumetric-modulated arc (RA) to conventional intensity modulated (IMRT) for involved-field (IFRT) and involved-node (INRT) radiotherapy for Hodgkin lymphoma (HL). Methods and Materials: Plans for 10 early-stage HL female patients were computed for RA and IMRT. First, the planning target volume (PTV) coverage and organs at risk (OAR) dose deposition was assessed between the two modalities. Second, the OAR (lung, breast, heart, thyroid, and submandibular gland) dose-volume histograms were computed and compared for IFRT and INRT, respectively. Results: For IFRT and INRT, PTV coverage was equally homogeneous with both RA and IMRT. By and large, the OAR irradiation with IFRT planning was not significantly different between RA and IMRT. For INRT, doses computed for RA were, however, usually lower than those with IMRT, particularly so for the lung, breast, and thyroid. Regardless of RA and IMRT modalities, a significant 20-50% decrease of the OAR computed mean doses was observed with INRT when compared with IFRT (Breast D{sub Mean} 1.5 +- 1.1 vs. 2.6 +- 1.7 Gy, p < 0.01 and 1.6 +- 1.1 vs. 2.9 +- 1.9 Gy, p < 0.01 for RA and IMRT, respectively). Conclusions: RA and IMRT results in similar level of dose homogeneity. With INRT but not IFRT planning, the computed doses to the PTV and OAR were usually higher and lower with RA when compared to IMRT. Regardless of the treatment modality, INRT when compared with IFRT planning led to a significant decrease in OAR doses, particularly so for the breast and heart.

  1. Intensity-Modulated Proton Therapy Reduces the Dose to Normal Tissue Compared With Intensity-Modulated Radiation Therapy or Passive Scattering Proton Therapy and Enables Individualized Radical Radiotherapy for Extensive Stage IIIB Non-Small-Cell Lung Cancer: A Virtual Clinical Study

    SciTech Connect

    Zhang Xiaodong; Li Yupeng; Pan Xiaoning; Xiaoqiang, Li; Mohan, Radhe; Komaki, Ritsuko; Cox, James D.; Chang, Joe Y.

    2010-06-01

    Purpose: To compare dose volume histograms of intensity-modulated proton therapy (IMPT) with those of intensity-modulated radiation therapy (IMRT) and passive scattering proton therapy (PSPT) for the treatment of stage IIIB non-small-cell lung cancer (NSCLC) and to explore the possibility of individualized radical radiotherapy. Methods and Materials: Dose volume histograms designed to deliver IMRT at 60 to 63 Gy, PSPT at 74 Gy, and IMPT at the same doses were compared and the use of individualized radical radiotherapy was assessed in patients with extensive stage IIIB NSCLC (n = 10 patients for each approach). These patients were selected based on their extensive disease and were considered to have no or borderline tolerance to IMRT at 60 to 63 Gy, based on the dose to normal tissue volume constraints (lung volume receiving 20 Gy [V20] of <35%, total mean lung dose <20 Gy; spinal cord dose, <45 Gy). The possibility of increasing the total tumor dose with IMPT for each patient without exceeding the dose volume constraints (maximum tolerated dose [MTD]) was also investigated. Results: Compared with IMRT, IMPT spared more lung, heart, spinal cord, and esophagus, even with dose escalation from 63 Gy to 83.5 Gy, with a mean MTD of 74 Gy. Compared with PSPT, IMPT allowed further dose escalation from 74 Gy to a mean MTD of 84.4 Gy (range, 79.4-88.4 Gy) while all parameters of normal tissue sparing were kept at lower or similar levels. In addition, IMPT prevented lower-dose target coverage in patients with complicated tumor anatomies. Conclusions: IMPT reduces the dose to normal tissue and allows individualized radical radiotherapy for extensive stage IIIB NSCLC.

  2. Planning tools for modulated electron radiotherapy

    SciTech Connect

    Surucu, Murat; Klein, Eric E.; Mamalui-Hunter, Maria; Mansur, David B.; Low, Daniel A.

    2010-05-15

    Purpose: To develop tools to plan modulated electron radiotherapy (MERT) and to compare the MERT plans to conventional or intensity modulated radiotherapy (IMRT) treatment plans. Methods: Monte Carlo dose calculations of electron fields shaped with the inherent photon multileaf collimators (MLCs) were investigated in this study. Treatment plans for four postmastectomy breast cancer patients were generated using MERT. The distances from the patient skin surfaces to the distal planning target volume surfaces were computed along the beam axis direction to determine the physical depth. Electron beam energies were selected to provide target coverage at these depths and energy bins were generated. A custom built MERT treatment planning graphical user interface (MERTgui) was used to shape the electron bins into deliverable electron segments. Monte Carlo dose distribution simulations were performed using the MLC-defined segments generated from the MERTgui. A custom built superposition gui was used to combine doses for each segment using relative weights and final MERT treatment plans were compared to the conventional or IMRT treatment plans. In addition, a demonstration of combined MERT and IMRT treatment plans was performed. Results: The MERT treatment plans provided acceptable target organ coverage in all cases. Relative to 3D conventional or IMRT treatment plans, the MERT plans predicted lower heart doses in all cases; average of the heart D{sub 20} of all plans was reduced from 14.1 to 3.3 Gy. The contralateral breast and contralateral lung doses decreased substantially with MERT planning compared to IMRT (on average, contralateral breast heart D{sub 20} was reduced from 8.7 to 0.7 Gy and contralateral lung D{sub 20} was reduced from 8.4 to 1.2 Gy with MERT). Ipsilateral lung D{sub 20} was lower with MERT than with the conventional plans (44.6 vs 29.2 Gy with MERT), but greater when compared against IMRT treatment plans (25.4 vs 28.9 Gy with MERT). A MERT and IMRT

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    2013-01-01

    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. PMID:23336502

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

    SciTech Connect

    Graf, Reinhold; Boehmer, Dirk; Budach, Volker; Wust, Peter

    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

  6. Predicted Risk of Radiation-Induced Cancers After Involved Field and Involved Node Radiotherapy With or Without Intensity Modulation for Early-Stage Hodgkin Lymphoma in Female Patients

    SciTech Connect

    Weber, Damien C.; Johanson, Safora; Peguret, Nicolas; Cozzi, Luca; Olsen, Dag R.

    2011-10-01

    Purpose: To assess the excess relative risk (ERR) of radiation-induced cancers (RIC) in female patients with Hodgkin lymphoma (HL) female patients treated with conformal (3DCRT), intensity modulated (IMRT), or volumetric modulated arc (RA) radiation therapy. Methods and Materials: Plans for 10 early-stage HL female patients were computed for 3DCRT, IMRT, and RA with involved field RT (IFRT) and involvednode RT (INRT) radiation fields. Organs at risk dose--volume histograms were computed and inter-compared for IFRT vs. INRT and 3DCRT vs. IMRT/RA, respectively. The ERR for cancer induction in breasts, lungs, and thyroid was estimated using both linear and nonlinear models. Results: The mean estimated ERR for breast, lung, and thyroid were significantly lower (p < 0.01) with INRT than with IFRT planning, regardless of the radiation delivery technique used, assuming a linear dose-risk relationship. We found that using the nonlinear model, the mean ERR values were significantly (p < 0.01) increased with IMRT or RA compared to those with 3DCRT planning for the breast, lung, and thyroid, using an IFRT paradigm. After INRT planning, IMRT or RA increased the risk of RIC for lung and thyroid only. Conclusions: In this comparative planning study, using a nonlinear dose--risk model, IMRT or RA increased the estimated risk of RIC for breast, lung, and thyroid for HL female patients. This study also suggests that INRT planning, compared to IFRT planning, may reduce the ERR of RIC when risk is predicted using a linear model. Observing the opposite effect, with a nonlinear model, however, questions the validity of these biologically parameterized models.

  7. Feasibility Study of Moderately Accelerated Intensity-Modulated Radiotherapy Plus Concurrent Weekly Cisplatin After Induction Chemotherapy in Locally Advanced Head-and Neck Cancer

    SciTech Connect

    Morganti, Alessio G.; Mignogna, Samantha; Deodato, Francesco; Massaccesi, Mariangela; Cilla, Savino; Calista, Franco; Serafini, Giovanni; Digesu, Cinzia; Macchia, Gabriella; Picardi, Vincenzo; Caravatta, Luciana; Di Lullo, Liberato; Giglio, Gianfranco; Sallustio, Giuseppina; Piermattei, Angelo

    2011-03-15

    Purpose: To evaluate the feasibility and efficacy of moderately accelerated intensity-modulated radiation therapy (IMRT) along with weekly cisplatin, after induction chemotherapy, in patients with locally advanced unresectable head and neck cancer (HNC). Methods and Materials: Patients with Stage III or IV locally advanced HNC, without progressive disease after three courses of induction chemotherapy, received concurrent chemo-IMRT (weekly cisplatin 30 mg/m{sup 2} plus simultaneous integrated boost IMRT). A total of 67.5 Gy in 30 fractions were delivered to primary tumor and involved nodes, 60 Gy in 30 fractions to high-risk nodal areas, and 55.5 Gy in 30 fractions to low-risk nodal areas. Results: In all, 36 patients (median age, 56 years) with International Union Against Cancer (UICC) Stage III (n = 5) and IV (n = 31) were included. Of the 36 patients, 17 had received CF (cisplatin and 5-fluorouracil (CF) and 19 had received docetaxel cisplatin and 5-fluorouracil (DCF). During concurrent chemoradiation, 11 of 36 patients (30.5%) experienced Grade III mucositis (CF, 47%; DCF, 15%; p < 0.04). Grade III pharyngeal-esophageal toxicity was observed in 5 of 19 patients (26.3%; CF, 0.0%; DCF, 26.3%; p = 0.02). Two patients died of complications (5.5%). After chemoradiation, the complete response rate was 63.8%. Two-year local control was 88.7%. Two-year progression free survival and overall survival were 74.5% and 60.9%, respectively. Conclusions: In our experience, a moderately accelerated chemo-IMRT was feasible after induction chemotherapy. However, a noteworthy early death rate of 5.5% was observed. Intensive supportive care strategies should be defined to better manage radiation-induced toxic effects. Longer follow-up is required to determine the incidence of late radiation toxicities and tumor control rates.

  8. [Radiotherapy of a glioma in a pregnant woman: evaluation of the foetal dose in conformational 3D or intensity-modulated].

    PubMed

    Lefebvre, L; Doyeux, K; Linca, S; Challand, T; Hanzen, C

    2014-12-01

    The purpose was to assess three treatments planning techniques including one in intensity-modulated radiation therapy (IMRT) for cerebral irradiation of pregnant woman, in order to limit the dose delivered to the foetus. The treatment provided was 60 Gy to the planning target volume. Estimated foetal dose was measured using an anthropomorphic phantom, on the upper and middle part of the uterus. The first plan consisted in four beams in conformational technique delivered from a Varian accelerator with a 120 leaves collimator, the second one used non-coplanar fields and the third one assessed IMRT. With the conformational technique, the dose at the upper part of the uterus was 8.3 mGy and 6.3 mGy at the middle part. The dose delivered to the foetus was higher with the non-coplanar fields. In IMRT, the dose at the upper part of the uterus was 23.8 mGy and 14.3 mGy at the middle part. The three plans used 6 MV X-rays. Because of the use of leaves and non-coplanar fields, IMRT does not seem to be the optimal technique for the treatment of pregnant woman. However, the dose delivered to the foetus remains low and below the dose of 100 mGy recommended by the International Commission of Radiological Protection. It seems possible to consider the use of this technique for a better sparing of organs at risk for the mother.

  9. Dose-escalated intensity-modulated radiotherapy and irradiation of subventricular zones in relation to tumor control outcomes of patients with glioblastoma multiforme

    PubMed Central

    Kusumawidjaja, Grace; Gan, Patricia Zhun Hong; Ong, Whee Sze; Teyateeti, Achiraya; Dankulchai, Pittaya; Tan, Daniel Yat Harn; Chua, Eu Tiong; Chua, Kevin Lee Min; Tham, Chee Kian; Wong, Fuh Yong; Chua, Melvin Lee Kiang

    2016-01-01

    Background Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor with high relapse rate. In this study, we aimed to determine if dose-escalated (DE) radiotherapy improved tumor control and survival in GBM patients. Methods We conducted a retrospective analysis of 49 and 23 newly-diagnosed histology-proven GBM patients, treated with DE radiotherapy delivered in 70 Gy (2.33 Gy per fraction) and conventional doses (60 Gy), respectively, between 2007 and 2013. Clinical target volumes for 70 and 60 Gy were defined by 0.5 and 2.0 cm expansion of magnetic resonance imaging T1-gadolinium-enhanced tumor/surgical cavity, respectively. Bilateral subventricular zones (SVZ) were contoured on a co-registered pre-treatment magnetic resonance imaging and planning computed tomography dataset as a 5 mm wide structure along the lateral margins of the lateral ventricles. Survival outcomes of both cohorts were compared using log-rank test. Radiation dose to SVZ in the DE cohort was evaluated. Results Median follow-up was 13.6 and 15.1 months for the DE- and conventionally-treated cohorts, respectively. Median overall survival (OS) of patients who received DE radiotherapy was 15.2 months (95% confidence interval [CI] =11.0–18.6), while median OS of the latter cohort was 18.4 months (95% CI =12.5–31.4, P=0.253). Univariate analyses of clinical and dosimetric parameters among the DE cohort demonstrated a trend of longer progression-free survival, but not OS, with incremental radiation doses to the ipsilateral SVZ (hazard ratio [HR] =0.95, 95% CI =0.90–1.00, P=0.052) and proportion of ipsilateral SVZ receiving 50 Gy (HR =0.98, 95% CI =0.97–1.00, P=0.017). Conclusion DE radiotherapy did not improve survival in patients with GBM. Incorporation of ipsilateral SVZ as a radiotherapy target volume for patients with GBM requires prospective validation. PMID:27042103

  10. Dose Sparing of Brainstem and Spinal Cord for Re-Irradiating Recurrent Head and Neck Cancer with Intensity-Modulated Radiotherapy

    SciTech Connect

    Chen, Chin-Cheng; Lee, Chen-Chiao; Mah, Dennis; Sharma, Rajiv; Landau, Evan; Garg, Madhur; Wu, Andrew

    2011-04-01

    Because of the dose limit for critical structures such as brainstem and spinal cord, administering a dose of 60 Gy to patients with recurrent head and neck cancer is challenging for those who received a previous dose of 60-70 Gy. Specifically, previously irradiated head and neck patients may have received doses close to the tolerance limit to their brainstem and spinal cord. In this study, a reproducible intensity-modulated radiation therapy (IMRT) treatment design is presented to spare the doses to brainstem and spinal cord, with no compromise of prescribed dose delivery. Between July and November 2008, 7 patients with previously irradiated, recurrent head and neck cancers were treated with IMRT. The jaws of each field were set fixed with the goal of shielding the brainstem and spinal cord at the sacrifice of partial coverage of the planning target volume (PTV) from any particular beam orientation. Beam geometry was arranged to have sufficient coverage of the PTV and ensure that the constraints of spinal cord <10 Gy and brainstem <15 Gy were met. The mean maximum dose to the brainstem was 12.1 Gy (range 6.1-17.3 Gy), and the corresponding mean maximum dose to spinal cord was 10.4 Gy (range 8.2-14.1 Gy). For most cases, 97% of the PTV volume was fully covered by the 95% isodose volume. We found empirically that if the angle of cervical spine curvature (Cobb's angle) was less than {approx}30{sup o}, patients could be treated by 18 fields. Six patients met these criteria and were treated in 25 minutes per fraction. One patient exceeded a 30{sup o} Cobb's angle and was treated by 31 fields in 45 minutes per fraction. We have demonstrated a new technique for retreatment of head and neck cancers. The angle of cervical spine curvature plays an important role in the efficiency and effectiveness of our approach.

  11. Association Between Bone Marrow Dosimetric Parameters and Acute Hematologic Toxicity in Anal Cancer Patients Treated With Concurrent Chemotherapy and Intensity-Modulated Radiotherapy

    SciTech Connect

    Mell, Loren K. Schomas, David A.; Salama, Joseph K.; Devisetty, Kiran; Aydogan, Bulent; Miller, Robert C.; Jani, Ashesh B.; Kindler, Hedy L.; Roeske, John C.; Chmura, Steven J.

    2008-04-01

    Purpose: To test the hypothesis that the volume of pelvic bone marrow (PBM) receiving 10 and 20 Gy or more (PBM-V{sub 10} and PBM-V{sub 20}) is associated with acute hematologic toxicity (HT) in anal cancer patients treated with concurrent chemoradiotherapy. Methods and Materials: We analyzed 48 consecutive anal cancer patients treated with concurrent chemotherapy and intensity-modulated radiation therapy. The median radiation dose to gross tumor and regional lymph nodes was 50.4 and 45 Gy, respectively. Pelvic bone marrow was defined as the region extending from the iliac crests to the ischial tuberosities, including the os coxae, lumbosacral spine, and proximal femora. Endpoints included the white blood cell count (WBC), absolute neutrophil count (ANC), hemoglobin, and platelet count nadirs. Regression models with multiple independent predictors were used to test associations between dosimetric parameters and HT. Results: Twenty patients (42%) had Stage T3-4 disease; 15 patients (31%) were node positive. Overall, 27 (56%), 24 (50%), 4 (8%), and 13 (27%) experienced acute Grade 3-4 leukopenia, neutropenia, anemia, and thrombocytopenia, respectively. On multiple regression analysis, increased PBM-V{sub 5}, V{sub 10}, V{sub 15}, and V{sub 20} were significantly associated with decreased WBC and ANC nadirs, as were female gender, decreased body mass index, and increased lumbosacral bone marrow V{sub 10}, V{sub 15}, and V{sub 20} (p < 0.05 for each association). Lymph node positivity was significantly associated with a decreased WBC nadir on multiple regression analysis (p < 0.05). Conclusion: This analysis supports the hypothesis that increased low-dose radiation to PBM is associated with acute HT during chemoradiotherapy for anal cancer. Techniques to limit bone marrow irradiation may reduce HT in anal cancer patients.

  12. The correlation between the comprehensive nutrition index and quality of life of patients with nasopharyngeal carcinoma treated by intensity-modulated radiotherapy.

    PubMed

    Ma, Liqin; Wu, Tingting; Pan, Jianji; Kong, Xiangquan; Guo, Qiaojuan; Yang, Ling; Zhang, Yu; Lin, Shaojun; Chen, Chuanben; Huang, Chaobin

    2014-01-01

    The purpose of this study was to compare the changing tendency of nutrition with 54 nasopharyngeal carcinoma patients during intensity-modulated radiation therapy (IMRT), and to investigate the correlation between comprehensive nutritional status and quality of life (QoL), which was assessed by the European Organization for Research and Treatment of Cancer Core Quality-of-Life Questionnaire. The nutritional index, including body mass index, ideal body weight percentage, usual body weight percentage, albumin, hemoglobin, and total lymphocyte count (TLC), was evaluated at 2 time points: within 48 h after admission (T1) and at the end of treatment with IMRT (T2). A statistically significant downgrade of every index was observed during IMRT. A comprehensive nutritional model was established by principal components analysis at T2. QoL scores of functional (P = 0.002) and the global QoL scales (P = 0.001) existed a positive correlation with comprehensive nutritional status. QoL scores of symptom scales (P = 0.002) and 6 single items (P = 0.005) had a negative correlation with it. The scores of global QoL scales in comprehensive nutrition of normal (20.4%), moderate (55.6%), and severe malnutrition (24.1%) were 69.70 ± 17.98, 48.33 ± 19.25, and 37.18 ± 24.67, respectively. Patients with different nutritional status had different QoL (B = 10.405, SE = 2.828, t = 3.680, P = 0.001). Multiaspect nutritional supports should be enhanced to improve patients' comprehensive nutritional status during treatment.

  13. International prostate symptom score (IPSS) change and changing factor in intensity-modulated radiotherapy combined with androgen deprivation therapy for prostate cancer

    PubMed Central

    Tomita, Natsuo; Oze, Isao; Shimizu, Hidetoshi; Yoshida, Maiko; Kimura, Kana; Takehana, Keiichi; Shimizu, Arisa; Makita, Chiyoko; Tachibana, Hiroyuki; Kodaira, Takeshi; Soga, Norihito; Ogura, Yuji; Hayashi, Norio

    2015-01-01

    ABSTRACT The purposes of this study on prostate cancer are to demonstrate the time course of International Prostate Symptom Score (IPSS) after intensity-modulated radiation therapy (IMRT) combined with androgen deprivation therapy (ADT) and to examine the factor associated with the IPSS change. This study included 216 patients treated with IMRT between 2006 and 2010. Patients were evaluated in three groups according to baseline IPSS as defined by the American Urological Association classification, where IPSSs of 0 to 7, 8 to 19, and 20 to 35 represent mild (n = 124), moderate (n = 70), and severe (n = 22) symptom groups, respectively. The average IPSSs ± standard deviation at baseline vs. those at 24 months after IMRT were 3.5 ± 2.1 vs. 5.1 ± 3.6 in the mild group (P < 0.001), 12.6 ± 3.4 vs. 10.0 ± 6.0 in the moderate group (P = 0.0015), and 23.8 ± 2.9 vs. 14.4 ± 9.1 in the severe group (P < 0.001). Among factors of patient and treatment characteristics, age, IPSS classification, pretreatment GU medications, and positive biopsy rates were associated with the IPSS difference between baseline and 24 months (P = 0.023, < 0.001, 0.044, and 0.028, respectively). In conclusion, patients with moderate to severe urinary symptoms can exhibit improvement in urinary function after IMRT, whereas patients with mild symptoms may have slightly worsened functions. Age, baseline IPSS, GU medications, and tumor burden in the prostate can have an effect on the IPSS changes. PMID:26663942

  14. International prostate symptom score (IPSS) change and changing factor in intensity-modulated radiotherapy combined with androgen deprivation therapy for prostate cancer.

    PubMed

    Tomita, Natsuo; Oze, Isao; Shimizu, Hidetoshi; Yoshida, Maiko; Kimura, Kana; Takehana, Keiichi; Shimizu, Arisa; Makita, Chiyoko; Tachibana, Hiroyuki; Kodaira, Takeshi; Soga, Norihito; Ogura, Yuji; Hayashi, Norio

    2015-11-01

    The purposes of this study on prostate cancer are to demonstrate the time course of International Prostate Symptom Score (IPSS) after intensity-modulated radiation therapy (IMRT) combined with androgen deprivation therapy (ADT) and to examine the factor associated with the IPSS change. This study included 216 patients treated with IMRT between 2006 and 2010. Patients were evaluated in three groups according to baseline IPSS as defined by the American Urological Association classification, where IPSSs of 0 to 7, 8 to 19, and 20 to 35 represent mild (n = 124), moderate (n = 70), and severe (n = 22) symptom groups, respectively. The average IPSSs ± standard deviation at baseline vs. those at 24 months after IMRT were 3.5 ± 2.1 vs. 5.1 ± 3.6 in the mild group (P < 0.001), 12.6 ± 3.4 vs. 10.0 ± 6.0 in the moderate group (P = 0.0015), and 23.8 ± 2.9 vs. 14.4 ± 9.1 in the severe group (P < 0.001). Among factors of patient and treatment characteristics, age, IPSS classification, pretreatment GU medications, and positive biopsy rates were associated with the IPSS difference between baseline and 24 months (P = 0.023, < 0.001, 0.044, and 0.028, respectively). In conclusion, patients with moderate to severe urinary symptoms can exhibit improvement in urinary function after IMRT, whereas patients with mild symptoms may have slightly worsened functions. Age, baseline IPSS, GU medications, and tumor burden in the prostate can have an effect on the IPSS changes.

  15. Feasibility and efficacy of helical intensity-modulated radiotherapy for stage III non-small cell lung cancer in comparison with conventionally fractionated 3D-CRT

    PubMed Central

    He, Jian; Huang, Yan; Chen, Yixing; Shi, Shiming; Ye, Luxi; Hu, Yong; Zhang, Jianying

    2016-01-01

    Background The standard treatment for stage III non-small-cell lung cancer (NSCLC) is still 60 Gy in conventional fractions combined with concurrent chemotherapy; however, the resulting local controls are disappointing. The aim of this study was to compare and assess the feasibility and efficacy of hypofractionated chemoradiotherapy using helical tomotherapy (HT) with conventional fractionation as opposed to using three-dimensional conformal radiotherapy (3D-CRT) for stage III NSCLC. Methods Sixty-nine patients with stage III (AJCC 7th edition) NSCLC who underwent definitive radiation treatment at our institution between July 2011 and November 2013 were reviewed and analyzed retrospectively. A dose of 60 Gy in 20 fractions was delivered in the HT group (n=34), whereas 60 Gy in 30 fractions in the 3D-CRT group (n=35). Primary endpoints were toxicity, overall response rate, overall survival (OS) and progression-free survival (PFS). Results The median follow-up period was 26.4 months. V20 (P=0.005), V30 (P=0.001), V40 (P=0.004), mean lung dose (P=0.000) and max dose of spinal cord (P=0.005) were significantly lower in the HT group than in the 3D-CRT group. There was no significant difference in the incidences of acute radiation pneumonitis (RP) ≥ grade 2 between the two groups, whereas the incidences of acute radiation esophagitis ≥ grade 2 were significantly lower in the HT group than in the 3D-CRT group (P=0.027). Two-year overall response rate was significantly higher in the HT group than in the 3D-CRT group (P=0.015). One- and 2-year OS rates were significantly higher in the HT group (95.0% and 68.7%, respectively) than in the 3D-CRT group (85.5% and 47.6%, respectively; P=0.0236). One- and 2-year PFS rates were significantly higher in the HT group (57.8% and 26.3%, respectively) than in the 3D-CRT group (32.7% and 11.4%, respectively; P=0.0351). Univariate analysis indicated that performance status (PS), T stage and radiotherapy technique were significant

  16. Effective avoidance of a functional spect-perfused lung using intensity modulated radiotherapy (IMRT) for non-small cell lung cancer (NSCLC): an update of a planning study.

    PubMed

    Lavrenkov, Konstantin; Singh, Shalini; Christian, Judith A; Partridge, Mike; Nioutsikou, Elena; Cook, Gary; Bedford, James L; Brada, Michael

    2009-06-01

    IMRT and 3-dimensional conformal radiotherapy (3-DCRT) plans of 25 patients with non-small cell lung (NSCLC) were compared in terms of planning target volume (PTV) coverage and sparing of functional lung (FL) defined by a SPECT perfusion scan. IMRT resulted in significant reduction of functional V(20) and mean lung dose in stage III patients with inhomogeneous hypoperfusion. If the dose to FL is shown to be the determinant of lung toxicity, IMRT would allow for effective dose escalation by specific avoidance of functional lung. PMID:18995919

  17. Helical intensity-modulated Radiotherapy of the Pelvic Lymph Nodes with Integrated Boost to the Prostate Bed - Initial Results of the PLATIN 3 Trial

    PubMed Central

    2014-01-01

    Background Adjuvant and salvage radiotherapy of the prostate bed are established treatment options for prostate cancer. While the benefit of an additional radiotherapy of the pelvic lymph nodes is still under debate, the PLATIN 3 prospective phase II clinical trial was initiated to substantiate toxicity data on postoperative IMRT of the pelvic lymph nodes and the prostate bed. Methods From 2009 to 2011, 40 patients with high-risk prostate cancer after prostatectomy with pT3 R0/1 M0 or pT2 R1 M0 or a PSA recurrence and either > 20% risk of lymph node involvement and inadequate lymphadenectomy or pN + were enrolled. Patients received two months of antihormonal treatment (AT) before radiotherapy. AT continuation was mandatory during radiotherapy and was recommended for another two years. IMRT of the pelvic lymph nodes (51.0 Gy) with a simultaneous integrated boost to the prostate bed (68.0 Gy) was performed in 34 fractions. PSA level, prostate-related symptoms and quality of life were assessed at regular intervals for 24 months. Results Of the 40 patients enrolled, 39 finished treatment as planned. Overall acute toxicity rates were low and no acute grade 3/4 toxicity occurred. Only 22.5% of patients experienced acute grade 2 gastrointestinal (GI) and genitourinary (GU) toxicity. During follow-up, 10.0% late grade 2 GI and 5.0% late grade 2 GU toxicity occurred, and one patient developed late grade 3 proctitis and enteritis. After a median observation time of 24 months the PLATIN 3 trial has shown in 97.5% of all patients sufficient safety and thus met its prospectively defined aims. After a median of 24 months, 34/38 patients were free of a PSA recurrence. Conclusions Postoperative whole-pelvis IMRT with an integrated boost to the prostate bed can be performed safely and without excessive toxicity. Trial registration Trial Numbers: ARO 2009–05, ClinicalTrials.gov: NCT01903408. PMID:24422782

  18. Light intensity modulation in phototherapy

    NASA Astrophysics Data System (ADS)

    Lukyanovich, P. A.; Zon, B. A.; Kunin, A. A.; Pankova, S. N.

    2015-04-01

    A hypothesis that blocking ATP synthesis is one of the main causes of the stimulating effect is considered based on analysis of the primary photostimulation mechanisms. The light radiation intensity modulation is substantiated and the estimates of such modulation parameters are made. An explanation is offered to the stimulation efficiency decrease phenomenon at the increase of the radiation dose during the therapy. The results of clinical research of the medical treatment in preventive dentistry are presented depending on the spectrum and parameters of the light flux modulation.

  19. Energy Modulated Photon Radiotherapy: A Monte Carlo Feasibility Study

    PubMed Central

    Zhang, Ying; Feng, Yuanming; Ming, Xin

    2016-01-01

    A novel treatment modality termed energy modulated photon radiotherapy (EMXRT) was investigated. The first step of EMXRT was to determine beam energy for each gantry angle/anatomy configuration from a pool of photon energy beams (2 to 10 MV) with a newly developed energy selector. An inverse planning system using gradient search algorithm was then employed to optimize photon beam intensity of various beam energies based on presimulated Monte Carlo pencil beam dose distributions in patient anatomy. Finally, 3D dose distributions in six patients of different tumor sites were simulated with Monte Carlo method and compared between EMXRT plans and clinical IMRT plans. Compared to current IMRT technique, the proposed EMXRT method could offer a better paradigm for the radiotherapy of lung cancers and pediatric brain tumors in terms of normal tissue sparing and integral dose. For prostate, head and neck, spine, and thyroid lesions, the EMXRT plans were generally comparable to the IMRT plans. Our feasibility study indicated that lower energy (<6 MV) photon beams could be considered in modern radiotherapy treatment planning to achieve a more personalized care for individual patient with dosimetric gains. PMID:26977413

  20. Outcomes of high-dose intensity-modulated radiotherapy alone with 1 cm planning target volume posterior margin for localized prostate cancer

    PubMed Central

    2013-01-01

    Background Clinically localized prostate cancer may be treated by different approaches of radiation therapy. The aim of this study was to report the results of disease control and toxicity in patients with clinically localized prostate cancer treated with high dose IMRT alone with 1 cm PTV posterior margin. Methods From September 2001 to April 2008, 140 patients with localized prostate cancer were treated with definitive IMRT (dose ≥ 74 Gy) without hormone therapy. Outcomes were measured from the conclusion of radiotherapy. Biochemical failure was defined as PSA nadir + 2.0 ng/dL. Toxicities were assessed using the NCI-CTCAE-version 3.0. Median follow-up was 58 months. Results Biochemical failure occurred in 13.6% of patients. Actuarial 5-year biochemical control rates were 91.7%, 82.5% and 85.9% for low-, intermediate-, and high-risk patients, respectively. Stage T2 patients presented a risk of biochemical failure almost three times higher than stage T1 (RR = 2.91; 95% CI: 1.04; 8.17). Distant metastases occurred in 3 (2%) patients. Five-year metastasis-free and overall survivals were 96% and 97.5%, respectively. Late grade 3 genitourinary and gastrointestinal toxicity rates were, respectively, 1.6% and 3%. Conclusion High-dose IMRT alone with 1 cm posterior PTV margin was effective and safe for patients with localized prostate cancer. PMID:24314072

  1. Dosimetric Effect of Intrafraction Motion and Residual Setup Error for Hypofractionated Prostate Intensity-Modulated Radiotherapy With Online Cone Beam Computed Tomography Image Guidance

    SciTech Connect

    Adamson, Justus; Wu Qiuwen; Yan Di

    2011-06-01

    Purpose: To quantify the dosimetric effect and margins required to account for prostate intrafractional translation and residual setup error in a cone beam computed tomography (CBCT)-guided hypofractionated radiotherapy protocol. Methods and Materials: Prostate position after online correction was measured during dose delivery using simultaneous kV fluoroscopy and posttreatment CBCT in 572 fractions to 30 patients. We reconstructed the dose distribution to the clinical tumor volume (CTV) using a convolution of the static dose with a probability density function (PDF) based on the kV fluoroscopy, and we calculated the minimum dose received by 99% of the CTV (D{sub 99}). We compared reconstructed doses when the convolution was performed per beam, per patient, and when the PDF was created using posttreatment CBCT. We determined the minimum axis-specific margins to limit CTV D{sub 99} reduction to 1%. Results: For 3-mm margins, D{sub 99} reduction was {<=}5% for 29/30 patients. Using post-CBCT rather than localizations at treatment delivery exaggerated dosimetric effects by {approx}47%, while there was no such bias between the dose convolved with a beam-specific and patient-specific PDF. After eight fractions, final cumulative D{sub 99} could be predicted with a root mean square error of <1%. For 90% of patients, the required margins were {<=}2, 4, and 3 mm, with 70%, 40%, and 33% of patients requiring no right-left (RL), anteroposterior (AP), and superoinferior margins, respectively. Conclusions: For protocols with CBCT guidance, RL, AP, and SI margins of 2, 4, and 3 mm are sufficient to account for translational errors; however, the large variation in patient-specific margins suggests that adaptive management may be beneficial.

  2. Robotic radiosurgery vs. brachytherapy as a boost to intensity modulated radiotherapy for tonsillar fossa and soft palate tumors: the clinical and economic impact of an emerging technology.

    PubMed

    Nijdam, W; Levendag, P; Fuller, D; Schulz, R; Prevost, J-B; Noever, I; Uyl-de Groot, C

    2007-12-01

    As a basis for making decisions regarding optimal treatment for patients with tonsillar fossa and soft palate tumors, we conducted a preliminary investigation of costs and quality of life (QoL) for two modalities [brachytherapy (BT) and robotic radiosurgery] used to boost radiation to the primary tumors following external beam radiotherapy. BT was well established in our center; a boost by robotic radiosurgery was begun more recently in patients for whom BT was not technically feasible. Robotic radiosurgery boost treatment has the advantage of being non-invasive and is able to reach tumors in cases where there is deep parapharyngeal tumor extension. A neck dissection was performed for patients with nodal-positive disease. Quality of life (pain and difficulty swallowing) was established in long-term follow-up for patients undergoing BT and over a one-year follow-up in robotic radiosurgery patients. Total hospital costs for both groups were computed. Our results show that efficacy and quality of life at one year are comparable for BT and robotic radiosurgery. Total cost for robotic radiosurgery was found to be less than BT primarily due to the elimination of hospital admission and operating room expenses. Confirmation of robotic radiosurgery treatment efficacy and reduced morbidity in the long term requires further study. Quality of life and cost analyses are critical to Health Technology Assessments (HTA). The present study shows how a preliminary HTA of a new medical technology such as robotic radiosurgery with its typical hypofractionation characteristics might be based on short-term clinical outcomes and assumptions of equivalence.

  3. Comparison between nedaplatin and cisplatin plus docetaxel combined with intensity-modulated radiotherapy for locoregionally advanced nasopharyngeal carcinoma: a multicenter randomized phase II clinical trial

    PubMed Central

    Tang, Chunyuan; Wu, Fang; Wang, Rensheng; Lu, Heming; Li, Guisheng; Liu, Meilian; Zhu, Haisheng; Zhu, Jinxian; Zhang, Yong; Hu, Kai

    2016-01-01

    Nasopharyngeal carcinoma (NPC) is highly incident in southern China. Metastasis is the major cause of death in NPC patients. Concurrent chemoradiotherapy (CCRT) has been accepted as standard in the treatment of patients with locoregionally advanced nasopharyngeal carcinoma (NPC). However, induction chemotherapy (IC) also has benefits in this disease, especially in the patients with certain high-risk factors such as bulky and/or extensive nodal disease. It has been presented that adding IC to CCRT might be a reasonable approach and need more work to confirm. The optimal chemotherapeutic regimen combined with radiotherapy has not been determined so far. It is important to explore high effective and low toxic chemotherapy for the patients. In the multicenter prospective study, 223 patients with locoregionally advanced untreated NPC were randomized into experimental group and control group. The patients received two cycles of induction chemotherapy (IC) with docetaxel (DOC) plus nedaplatin (NDP) in experimental group every 3 weeks, followed by IMRT concurrent with weekly NDP for six cycles, and NDP was replaced by cisplatin (CDDP) in control group. More patients in experimental group could receive full courses of IC and concurrent chemoradiotherapy (CCRT) (P=0.013). There was no significant difference between the two groups in the percentage of reduction of GTVnx and GTVnd after IC (P=0.207 and P=0.107) and CR rate three months after completion of chemoradiotherapy (P=0.565 and P=0.738). With a mean follow-up of 35.1 months, no statistically significant difference in the 3-year OS, LRFS, RRFS, DMFS, and PFS was found. During IC, more patients suffered vomiting in control group (P=0.001). During CCRT, grade 3/4 neutropenia/thrombocytopenia were more common in experimental group (P=0.028 and P=0.035); whereas, severe anemia and vomiting were more common in control group (P=0.0001 and P=0.023). In conclusions, patients with locoregionally advanced NPC showed good

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

    SciTech Connect

    Bondar, M.L.; Hoogeman, M.S.; Mens, J.W.; Quint, S.; Ahmad, R.; Dhawtal, G.; Heijmen, B.J.

    2012-08-01

    bladder and rectum inside the PTV (0% to 10% and -1% to 9%; p < 0.004) and the CTV-to-PTV volume (4-96 ml). Conclusions: Compared with population-based margins, an individualized PTV results in better organ-at-risk sparing. Online-adaptive radiotherapy further improves organ-at-risk sparing.

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

    SciTech Connect

    Zelefsky, Michael J.; Housman, Douglas M.; Pei Xin; Alicikus, Zumre; Magsanoc, Juan Martin; Dauer, Lawrence T.; St Germain, Jean; Yamada, Yoshiya; Kollmeier, Marisa; Cox, Brett; Zhang Zhigang

    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 increased

  6. SU-E-T-198: Hippocampal-Sparing Radiotherapy (HSRT) for Patients with Head and Neck Cancer (HNC) Using Intensity-Modulated Radiation Therapy (IMRT)

    SciTech Connect

    Dunlop, A; Welsh, L; Nutting, C; Harrington, K; Bhide, S; Newbold, K

    2014-06-01

    Purpose: There is increasing evidence that decline in cognitive function following brain radiotherapy (RT) is related to the radiation dose delivered to the hippocampi. In this work we evaluate the feasibility of using IMRT to generate HSRT plans in HNC. Methods: A planning study was undertaken for ten representative patients with HNC previously treated with radical (chemo)-RT using standard IMRT techniques. The hippocampi were delineated according to the RTOG hippocampal contouring atlas, on a T1w- MRI scan that was registered with the RT planning CT. LINAC-based, clinically acceptable, HSRT plans were generated and assessed using the Pinnacle3 treatment planning system. Results: Using a VMAT technique, a reduction in hippocampal dose was achievable in six cases. For these cases, the EQD2-D40% of the bilateral hippocampi was significantly reduced by HSRT (p = 0.006) from a median of 18.8Gy (range 14.4–34.6) to 6.5 Gy (4.2–9.5) for the delivered and HSRT plans respectively. Plans were also generated using a fixed-field IMRT technique with non-coplanar beams that were designed to avoid the bilateral hippocampi, resulting in a median EQD2-D40% of 11.2Gy (8.0–14.5). Both HSRT techniques also resulted in lower doses to the whole brain, brain stem, and cerebellum. The HSRT plans resulted in higher doses to some regions of non-contoured normaltissue, but the magnitude of these dose differences is unlikely to be of clinical significance in terms of acute and late toxicity. Conclusion: This study has demonstrated that it is possible, in many cases, to adapt treatment plans for HNC to significantly reduce dose to the hippocampi. This reduction in dose would be predicted to Resultin a significant reduction in the probability of subsequent decline in cognitive function following RT. Our results point towards the need for the collection of prospective data on cognitive outcomes for the HNC patient population treated with radical (chemo)-RT.

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

    SciTech Connect

    Ai, H; Zhang, H

    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

  8. Validation of modulated electron radiotherapy delivered with photon multileaf collimation

    NASA Astrophysics Data System (ADS)

    Klein, Eric E.

    There is a challenge in radiotherapy to treat shallow targets due to the inability to provide dose heterogeneity while simultaneously minimizing dose to distal critical organs. There is a niche for Modulated Electron Radiotherapy (MERT) to complement a photon IMRT program. Disease sites such as post-mastectomy chest wall, and subcutaneous lymphoma of the scalp, etc. are better suited for modulated electrons rather than photons, or perhaps a combination. Inherent collimation systems are not conducive for electron beam delivery (in lieu of extended applicators), nor do commercial treatment planning systems model electrons collimated without applicators. The purpose of this study is to evaluate modulation of electrons by inherent photon multileaf collimators, and calculated and optimized by means of Monte Carlo. Modulated electron radiotherapy (MERT) evaluation was conducted with a Trilogy 120 leaf MLC for 6-20 MeV. To provide a sharp penumbra, modulated beams were delivered with short SSDs (70-85cm). Segment widths (SW) ranging from 1 to 10cm were configured for delivery and planning, using BEAMnrc MC code with 109 particles, and DOSXYZnrc calculations. Calculations were set with: voxel size 0.2 x 0.2 x 0.1cm3, and photon/electron transport energy cutoffs of 0.01 MeV/0.521 MeV. Dosimetry was performed with film and micro chambers. Calculated and measured data were analyzed in MatLab. Once validation of static fields was successfully completed, modulated portals (segmented and dynamic) were configured for treatment and calculations. Optimization for target coverage and OAR sparing was achieved by choosing energies according to target depth, and SW according to spatial coverage. Intensity for each segment was optimized by MC methods. Beam sharpness (penumbra) degraded with: decreasing energy and SW, and increasing SSD. PDD decreased significantly with decreasing SW. We have demonstrated excellent calculation/measurement agreement (<3mm). Equal dose profiles were

  9. Mild Toxicity and Favorable Prognosis of High-Dose and Extended Involved-Field Intensity-Modulated Radiotherapy for Patients With Early-Stage Nasal NK/T-Cell Lymphoma

    SciTech Connect

    Wang Hua; Li Yexiong; Wang Weihu; Jin Jing; Dai Jianrong; Wang Shulian; Liu Yueping; Song Yongwen; Wang Zhaoyang; Liu Qingfeng; Fang Hui; Qi Shunan; Liu Xinfan; Yu Zihao

    2012-03-01

    Purpose: The value of intensity-modulated radiotherapy (IMRT) for early-stage nasal NK/T-cell lymphoma has not been previously reported. The aim of the present study was to assess the dosimetric parameters, toxicity, and treatment outcomes of patients with nasal NK/T-cell lymphoma. Methods and Materials: Between 2003 and 2008, 42 patients with early-stage nasal NK/T-cell lymphoma underwent definitive high-dose and extended involved-field IMRT with or without combination chemotherapy. The median radiation dose to the primary tumor was 50 Gy. The dose-volume histograms of the target volume and critical normal structures were evaluated in all patients. The locoregional control, overall survival, and progression-free survival were calculated using the Kaplan-Meier method. Results: The average mean dose delivered to the planning target volume was 55.5 Gy. Only 1.3% and 2.5% of the planning target volume received <90% and 95% of the prescribed dose, respectively, indicating excellent planning target volume coverage. The mean dose and average dose to the parotid glands was 15 Gy and 14 Gy, respectively. With a median follow-up time of 27 months, the 2-year locoregional control, overall survival, and progression-free survivalrate was 93%, 78%, and 74%, respectively. No Grade 4 or 5 acute or late toxicity was reported. Conclusions: High-dose and extended involved-field IMRT for patients with early-stage nasal NK/T-cell lymphoma showed favorable locoregional control, overall survival, and progression-free survival, with mild toxicity. The dose constraints of IMRT for the parotid glands can be limited to <20 Gy in these patients.

  10. Use of a Conventional Low Neck Field (LNF) and Intensity-Modulated Radiotherapy (IMRT): No Clinical Detriment of IMRT to an Anterior LNF During the Treatment of Head-and Neck-Cancer

    SciTech Connect

    Turaka, Aruna; Li Tianyu; Nicolaou, Nicos; Lango, Miriam N.; Burtness, Barbara; Horwitz, Eric M.; Ridge, John A.; Feigenberg, Steven J.

    2011-01-01

    Purpose: To determine differences in clinical outcomes using intensity-modulated radiotherapy (IMRT) or a standard low neck field (LNF) to treat low neck. Methods and Materials: This is a retrospective, single-institution study. Ninety-one patients with squamous cell carcinoma of the head and neck were treated with curative intent. According to physician preference, some patients were treated with LNF (Planning Target Volume 3) field using a single anterior photon field matched to the IMRT field. Field junctions were not feathered. The endpoints were time to failure and use of a percutaneous endoscopic gastrostomy (PEG) tube (as a surrogate of laryngeal edema causing aspiration), and analysis was done with {chi}{sup 2} and log-rank tests. Results: Median follow-up was 21 months (range, 2-89 months). Median age was 60 years. Thirty-seven patients (41%) were treated with LNF, 84% were Stage III or IV. A PEG tube was required in 30%, as opposed to 33% without the use of LNF. Node 2 or 3 neck disease was treated more commonly without LNF (38% vs. 24%, p = 0.009). Failures occurred in 12 patients (13%). Only 1 patient treated with LNF failed regionally, 4.5 cm above the match line. The 3-year disease-free survival rate was 87% and 79% with LNF and without LNF, respectively (p = 0.2), and the 3-year LR failure rate was 4% and 21%, respectively (p = 0.04). Conclusions: Using LNF to treat the low neck did not increase the risk of regional failure 'in early T and early N diseases' or decrease PEG tube requirements.

  11. Dosimetric Comparison of Intensity-Modulated Radiotherapy Plans, With or Without Anterior Myocardial Territory and Left Ventricle as Organs at Risk, in Early-Stage Left-Sided Breast Cancer Patients

    SciTech Connect

    Tan Wenyong; Wang Xiaohong; Qiu Dasheng; Liu Dong; Jia Shaohui; Zeng Fanyu; Chen Zhengwang; Li Beihui; Xu Jiaozhen; Wei Lai; Hu Desheng

    2011-12-01

    Purpose: We evaluated heart sparing using an intensity-modulated radiotherapy (IMRT) plan with the left ventricle (LV) and/or the anterior myocardial territory (AMT) as additional organs at risk (OARs). Methods and Materials: A total of 10 patients with left-sided breast cancer were selected for dosimetric planning. Both lungs, the right breast, heart, LV, and AMT were defined as OARs. We generated one tangential field plan and four IMRT plans for each patient. We examined the dose-volume histogram parameters of the planning target volume and OARs. Results: Compared with the tangential field plan, the mean dose to the heart in the IMRT plans did not show significant differences; however, the dose to the AMT and LV decreased by 18.7-45.4% and 10.8-37.4%, respectively. The maximal dose to the heart decreased by 18.6-35.3%, to the AMT by 22.0-45.1%, and to the LV by 23.5-45.0%, And the relative volumes of the heart (V{sub {>=}12}), AMT (V{sub >11}) and LV (V{sub >10}) decreased significantly with different levels, respectively. The volume of the heart, AMT, LV, both lungs, and right breast receiving {>=}5 Gy showed a significant increase. Compared with the IMRT (H) plan, the mean dose to the heart, AMT, and LV decreased by 17.5-21.5%, 25.2-29.8%, and 22.8-29.8% and the maximal dose by 13.6-20.6%, 23.1-29.6%, and 17.3-29.1%, respectively. The IMRT plans for both lungs and the right breast showed no significant differences. Conclusions: The IMRT plans with the addition of the AMT and/or LV as OARs considerably increased heart sparing. We recommend including the LV as an additional OAR in such plans.

  12. Intensity-Modulated Radiotherapy for Cervical Node Squamous Cell Carcinoma Metastases From Unknown Head-and-Neck Primary Site: M. D. Anderson Cancer Center Outcomes and Patterns of Failure

    SciTech Connect

    Frank, Steven J.; Rosenthal, David I.; Petsuksiri, Janjira; Ang, K. Kian; Morrison, William H.; Weber, Randal S.; Glisson, Bonnie S.; El-Naggar, Adel K.; Garden, Adam S.

    2010-11-15

    Purpose: Conventional therapy for cervical node squamous cell carcinoma metastases from an unknown primary can cause considerable toxicity owing to the volume of tissues to be irradiated. In the present study, hypothesizing that using intensity-modulated radiotherapy (IMRT) would provide effective treatment with minimal toxicity, we reviewed the outcomes and patterns of failure for head-and-neck unknown primary cancer at a single tertiary cancer center. Methods and Materials: We retrospectively reviewed the records of 52 patients who had undergone IMRT for an unknown primary at M.D. Anderson Cancer Center between 1998 and 2005. The patient and treatment characteristics were extracted and the survival rates calculated using the Kaplan-Meier method. Results: Of the 52 patients, 5 presented with Stage N1, 11 with Stage N2a, 23 with Stage N2b, 6 with Stage N2c, 4 with Stage N3, and 3 with Stage Nx disease. A total of 26 patients had undergone neck dissection, 13 before and 13 after IMRT; 14 patients had undergone excisional biopsy and presented for IMRT without evidence of disease. Finally, 14 patients had received systemic chemotherapy. All patients underwent IMRT to targets on both sides of the neck and pharyngeal axis. The median follow-up time for the surviving patients was 3.7 years. The 5-year actuarial rate of primary mucosal tumor control and regional control was 98% and 94%, respectively. Only 3 patients developed distant metastasis with locoregional control. The 5-year actuarial disease-free and overall survival rate was 88% and 89%, respectively. The most severe toxicity was Grade 3 dysphagia/esophageal stricture, experienced by 2 patients. Conclusion: The results of our study have shown that IMRT can produce excellent outcomes for patients who present with cervical node squamous cell carcinoma metastases from an unknown head-and-neck primary tumor. Severe late complications were uncommon.

  13. Intensity-Modulated Radiotherapy Reduces Radiation-Induced Morbidity and Improves Health-Related Quality of Life: Results of a Nonrandomized Prospective Study Using a Standardized Follow-Up Program

    SciTech Connect

    Vergeer, Marije R. Doornaert, Patricia A.H.; Rietveld, Derek H.F.; Leemans, C. Rene; Langendijk, Johannes A.

    2009-05-01

    Purpose: The purpose of this study was to compare intensity-modulated radiation therapy (IMRT) and three-dimensional conventional radiotherapy (3D-CRT) with regard to patient-rated xerostomia, Radiation Therapy Oncology Group (RTOG) acute and late xerostomia and health-related quality of life (HRQoL) among patients with head and neck squamous cell carcinoma (HNSCC). Methods and Materials: Included were 241 patients with HNSCC treated with bilateral irradiation {+-} chemotherapy. Since 2000, all patients treated with HNSCC were included in a program, which prospectively assessed acute and late morbidity according to the RTOG and HRQoL on a routine basis at regular intervals. Before October 2004, all patients were treated with 3D-CRT (N = 150). After clinical implementation in October 2004, 91 patients received IMRT. In this study, the differences regarding RTOG toxicity, xerostomia, and other items of HRQoL were analyzed. Results: The use of IMRT resulted in a significant reduction of the mean dose of the parotid glands (27 Gy vs. 43 Gy (p < 0.001). During radiation, Grade 2 RTOG xerostomia was significantly less with IMRT than with 3D-CRT. At 6 months, the prevalence of patient-rated moderate to severe xerostomia and Grade 2 or higher RTOG xerostomia was significantly lower after IMRT versus 3D-CRT. Treatment with IMRT also had a positive effect on several general and head and neck cancer-specific HRQoL dimensions. Conclusions: IMRT results in a significant reduction of patient- and observer-rated xerostomia, as well as other head and neck symptoms, compared with standard 3D-CRT. These differences translate into a significant improvement of the more general dimensions of HRQoL.

  14. Intensity-modulated radiotherapy—what is it?

    PubMed Central

    Taylor, A; Powell, M E B

    2004-01-01

    Intensity-modulated radiotherapy (IMRT) is one of the most important recent developments in oncology. It enables precise conformation of the radiation dose to the target volume. It has the potential to significantly reduce long-term morbidity and improve local control. This article explains the basic principles of IMRT in comparison to other planning techniques. The current clinical data are presented and future lines of research are discussed. PMID:18250011

  15. Inverse planning of energy-modulated electron beams in radiotherapy

    SciTech Connect

    Gentry, John R. . E-mail: gentryj@gmh.org; Steeves, Richard; Paliwal, Bhudatt A.

    2006-01-01

    The use of megavoltage electron beams often poses a clinical challenge in that the planning target volume (PTV) is anterior to other radiosensitive structures and has variable depth. To ensure that skin as well as the deepest extent of the PTV receives the prescribed dose entails prescribing to a point beyond the depth of peak dose for a single electron energy. This causes dose inhomogeneities and heightened potential for tissue fibrosis, scarring, and possible soft tissue necrosis. Use of bolus on the skin improves the entrant dose at the cost of decreasing the therapeutic depth that can be treated. Selection of a higher energy to improve dose homogeneity results in increased dose to structures beyond the PTV, as well as enlargement of the volume receiving heightened dose. Measured electron data from a linear accelerator was used as input to create an inverse planning tool employing energy and intensity modulation using bolus (e-IMRT{sup TM}). Using tools readily available in a radiotherapy department, the applications of energy and intensity modulation on the central axis makes it possible to remove hot spots of 115% or more over the depths clinically encountered. The e-IMRT{sup TM} algorithm enables the development of patient-specific dose distributions with user-defined positions of peak dose, range, and reduced dose to points beyond the prescription point.

  16. Association between absolute volumes of lung spared from low-dose irradiation and radiation-induced lung injury after intensity-modulated radiotherapy in lung cancer: a retrospective analysis

    PubMed Central

    Chen, Jinmei; Hong, Jinsheng; Zou, Xi; Lv, Wenlong; Guo, Feibao; Hong, Hualan; Zhang, Weijian

    2015-01-01

    The aim of this study was to investigate the association between absolute volumes of lung spared from low-dose irradiation and radiation-induced lung injury (RILI) after intensity-modulated radiotherapy (IMRT) for lung cancer. The normal lung relative volumes receiving greater than 5, 10, 20 and 30 Gy (V5–30) mean lung dose (MLD), and absolute volumes spared from greater than 5, 10, 20 and 30 Gy (AVS5–30) for the bilateral and ipsilateral lungs of 83 patients were recorded. Any association of clinical factors and dose–volume parameters with Grade ≥2 RILI was analyzed. The median follow-up was 12.3 months; 18 (21.7%) cases of Grade 2 RILI, seven (8.4%) of Grade 3 and two (2.4%) of Grade 4 were observed. Univariate analysis revealed the located lobe of the primary tumor. V5, V10, V20, MLD of the ipsilateral lung, V5, V10, V20, V30 and MLD of the bilateral lung, and AVS5 and AVS10 of the ipsilateral lung were associated with Grade ≥2 RILI (P < 0.05). Multivariate analysis indicated AVS5 of the ipsilateral lung was prognostic for Grade ≥2 RILI (P = 0.010, OR = 0.272, 95% CI: 0.102–0.729). Receiver operating characteristic curves indicated Grade ≥2 RILI could be predicted using AVS5 of the ipsilateral lung (area under curve, 0.668; cutoff value, 564.9 cm3; sensitivity, 60.7%; specificity, 70.4%). The incidence of Grade ≥2 RILI was significantly lower with AVS5 of the ipsilateral lung ≥564.9 cm3 than with AVS5 < 564.9 cm3 (P = 0.008). Low-dose irradiation relative volumes and MLD of the bilateral or ipsilateral lung were associated with Grade ≥2 RILI, and AVS5 of the ipsilateral lung was prognostic for Grade ≥2 RILI for lung cancer after IMRT. PMID:26454068

  17. Intensity-Modulated Radiation Therapy (IMRT)

    MedlinePlus

    ... modulating—or controlling—the intensity of the radiation beam in multiple small volumes. IMRT also allows higher ... of multiple intensity-modulated fields coming from different beam directions produce a custom tailored radiation dose that ...

  18. Plasma optical modulators for intense lasers.

    PubMed

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

    2016-01-01

    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 10(16) 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. PMID:27283369

  19. Plasma optical modulators for intense lasers

    NASA Astrophysics Data System (ADS)

    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.

  20. Plasma optical modulators for intense lasers

    PubMed Central

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

    2016-01-01

    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. PMID:27283369

  1. Volumetric modulated arc therapy for hippocampal-sparing radiotherapy in transformed low-grade glioma: A treatment planning case report.

    PubMed

    Kazda, T; Pospisil, P; Vrzal, M; Sevela, O; Prochazka, T; Jancalek, R; Slampa, P; Laack, N N

    2015-05-01

    Timing of radiotherapy for low-grade gliomas is still controversial due to concerns of possible adverse late effects. Prevention of possible late cognitive sequelae by hippocampal avoidance has shown promise in phase II trials. A patient with progressive low-grade glioma with gradual dedifferentiation into anaplastic astrocytoma is presented along with description of radiotherapy planning process attempting to spare the hippocampus. To our knowledge, this is the first described case using volumetric modulated arc technique to spare hippocampus during transformed low-grade glioma radiotherapy. Using modern intensity-modulated radiotherapy systems it is possible to selectively spare hippocampus together with other standard organs at risk. For selected patients, an attempt to spare hippocampus can be considered as long as other dose characteristics are not significantly compromised compared to standard treatment plan created without any effort to avoid hippocampus. PMID:25835374

  2. Intensity modulated arc therapy (IMAT) with centrally blocked rotational fields.

    PubMed

    Cotrutz, C; Kappas, C; Webb, S

    2000-08-01

    A new technique for intensity-modulated beam (IMB) delivery that combines the features of intensity modulated arc therapy (IMAT) with the use of 'classical blocks' is proposed. The role of the blocks is to realize the high-gradient modulation of the intensity profile corresponding to the region to be protected within the body contour, while the MLC leaves or the secondary collimator defines the rest of the field and delivers intensity-modulated multiple rotational segments. The centrally blocked radiation fields are applied sequentially, in several rotations. Each rotation of the gantry is responsible for delivering one segment of the optimal intensity profile. The new IMAT technique is applied for a treatment geometry represented by an annular target volume centrally located within a circular body contour. The annulus encompasses a circular critical structure, which is to be protected. The beam opening and corresponding weight of each segment are determined in two ways. The first method applies a linear optimization algorithm to precalculated centrally blocked radial dose profiles. These radial profiles are calculated for a set of beam openings, ranging from the largest field that covers the whole planning target volume (PTV) to the smallest, which is 1 cm larger than the width of the central block. The optimization is subjected to dose homogeneity constraints imposed on a linear combination of these profiles and finally delivers the dimensions and weights of the rotational beams to be used in combination. The second method decomposes into several subfields the fluence profile of a rotational beam known to deliver a constant dose level to PTV. This fluence profile is determined by using the analytical method proposed by Brahme for the case of the annular PTV and the concentric organ at risk (OAR). The proper segmentation of this intensity profile provides the field sizes and corresponding weights of the subfields to be used in combination. Both methods show that

  3. Intensity-modulated radiation therapy: supportive data for prostate cancer.

    PubMed

    Cahlon, Oren; Hunt, Margie; Zelefsky, Michael J

    2008-01-01

    Since its introduction into clinical use in the mid-1990s, intensity-modulated radiation therapy (IMRT) has emerged as the most effective and widely used form of external-beam radiotherapy for localized prostate cancer. Multiple studies have confirmed the importance of delivering sufficiently high doses to the prostate to achieve cure. The dosimetric superiority of IMRT over conventional techniques to produce conformal dose distributions that allow for organ sparing has been shown. A growing number of reports have confirmed that IMRT is the safest way to deliver high doses of external-beam irradiation to the prostate and the regional lymph nodes. Advances in imaging and onboard verification systems continue to advance the capabilities of IMRT and have potential implications with regards to further dose escalation and hypofractionated regimens. The clinical data in support of IMRT and the associated technical aspects of IMRT treatment planning and implementation are highlighted in this review.

  4. Fan-beam intensity modulated proton therapy

    SciTech Connect

    Hill, Patrick; Westerly, David; Mackie, Thomas

    2013-11-15

    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

  5. Similarities between static and rotational intensity-modulated plans

    NASA Astrophysics Data System (ADS)

    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. Dosimetric Impact of Breathing Motion in Lung Stereotactic Body Radiotherapy Treatment Using Image-Modulated Radiotherapy and Volumetric Modulated Arc Therapy

    SciTech Connect

    Rao Min; Wu Jianzhou; Cao Daliang; Wong, Tony; Mehta, Vivek; Shepard, David; Ye Jinsong

    2012-06-01

    Purpose: The objective of this study was to investigate the influence of tumor motion on dose delivery in stereotactic body radiotherapy (SBRT) for lung cancer, using fixed field intensity- modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT). Methods and Materials: For each of 10 patients with stage I/II non-small-cell pulmonary tumors, a respiration-correlated four-dimensional computed tomography (4DCT) study was carried out. The internal target volume was delineated on the maximum intensity projection CT, which was reconstructed from the 4DCT dataset. A 5-mm margin was used for generation of the planning target volume. VMAT and five-field IMRT plans were generated using Pinnacle{sup 3} SmartArc and direct machine parameter optimization, respectively. All plans were generated for an Elekta Synergy linear accelerator using 6-MV photons. Simulation was performed to study the interplay between multileaf collimator (MLC) sequences and target movement during the delivery of VMAT and IMRT. For each plan, 4D dose was calculated using deformable image registration of the 4DCT images. Target volume coverage and doses to critical structures calculated using 4D methodology were compared with those calculated using 3D methodology. Results: For all patients included in this study, the interplay effect was found to present limited impact (less than 1% of prescription) on the target dose distribution, especially for SBRT, in which fewer fractions (three fractions) are delivered. Dose to the gross tumor volume (GTV) was, on average, slightly decreased (1% of prescription) in the 4D calculation compared with the 3D calculation. The motion impact on target dose homogeneity was patient-dependent and relatively small. Conclusions: Both VMAT and IMRT plans experienced negligible interplay effects between MLC sequence and tumor motion. For the most part, the 3D doses to the GTV and critical structures provided good approximations of the 4D dose calculations.

  7. Epithelioid hemangioendothelioma of the spine treated with RapidArc volumetric-modulated radiotherapy

    SciTech Connect

    Guy, Jean-Baptiste; Trone, Jane-Chloé; Chargari, Cyrus; Falk, Alexander Tuan; Khodri, Mustapha; Magné, Nicolas

    2014-10-01

    Radiotherapy for epithelioid hemangioendothelioma (EHE) using volumetric intensity-modulated arc radiotherapy (VMAT). A 48-year-old woman was referred for curative irradiation of a vertebral EHE after failure of surgery. A comparison between VMAT and conventional conformal tridimensional (3D) dosimetry was performed and potential advantage of VMAT for sparing critical organs from irradiation's side effects was discussed. The total delivered dose on the planning target volume was 54 Gy in 27 fractions. The patient was finally treated with VMAT. The tolerance was excellent. There was no acute toxicity, including no increase in pain. With a follow-up of 18 months, no delayed toxicity was reported. The clinical response consisted of a decrease in the dorsal pain. The D{sub max} for the spinal cord was reduced from 55 Gy (3D-radiotherapy [RT]) (which would be an unacceptable dose to the spine because of the risk of myelopathy) to 42.8 Gy (VMAT), which remains below the recommended dose threshold (45 Gy). The dose delivered to 20% of organ volume (D{sub 20}) was reduced from 47 Gy (3D-RT) to 3 Gy (VMAT) for the spinal cord. The study shows that VMAT allows the delivery of curative treatment for vertebral EHEs because of critical organ sparing.

  8. Fast-switching bistable cholesteric intensity modulator.

    PubMed

    Hsiao, Yu-Cheng; Tang, Chen-Yu; Lee, Wei

    2011-05-01

    A fast-switching bistable optical intensity modulator is demonstrated. Using a dual-frequency cholesteric liquid crystal, the direct switching is achieved from the scattering focal conic state to the transparent long-pitch planar state. In comparison with the bistable cholesteric devices proposed previously, our device, characterized by its capability of direct two-way transitions between the two bistable states, possesses a very short transition time from the focal conic state to the planar state as short as 10 ms. No voltage has to be applied to sustain the optical states, making the device low energy consuming. Potential applications of this device are addressed.

  9. Fast-switching bistable cholesteric intensity modulator.

    PubMed

    Hsiao, Yu-Cheng; Tang, Chen-Yu; Lee, Wei

    2011-05-01

    A fast-switching bistable optical intensity modulator is demonstrated. Using a dual-frequency cholesteric liquid crystal, the direct switching is achieved from the scattering focal conic state to the transparent long-pitch planar state. In comparison with the bistable cholesteric devices proposed previously, our device, characterized by its capability of direct two-way transitions between the two bistable states, possesses a very short transition time from the focal conic state to the planar state as short as 10 ms. No voltage has to be applied to sustain the optical states, making the device low energy consuming. Potential applications of this device are addressed. PMID:21643231

  10. The radiation techniques of tomotherapy & intensity-modulated radiation therapy applied to lung cancer

    PubMed Central

    Zhu, Zhengfei

    2015-01-01

    Radiotherapy (RT) plays an important role in the management of lung cancer. Development of radiation techniques is a possible way to improve the effect of RT by reducing toxicities through better sparing the surrounding normal tissues. This article will review the application of two forms of intensity-modulated radiation therapy (IMRT), fixed-field IMRT and helical tomotherapy (HT) in lung cancer, including dosimetric and clinical studies. The advantages and potential disadvantages of these two techniques are also discussed. PMID:26207214

  11. Preliminary results of a phase I/II study of simultaneous modulated accelerated radiotherapy for nondisseminated nasopharyngeal carcinoma

    SciTech Connect

    Lee, Sang-wook . E-mail: lsw@amc.seoul.kr; Back, Geum Mun; Yi, Byong Yong; Choi, Eun Kyung; Ahn, Seung Do; Shin, Seong Soo; Kim, Jung-hun; Kim, Sang Yoon; Lee, Bong-Jae; Nam, Soon Yuhl; Choi, Seung-Ho; Kim, Seung-Bae; Park, Jin-hong; Lee, Kang Kyoo; Park, Sung Ho; Kim, Jong Hoon

    2006-05-01

    Purpose: To present preliminary results of intensity-modulated radiotherapy (IMRT) with the simultaneous modulated accelerated radiotherapy (SMART) boost technique in patients with nasopharyngeal carcinoma (NPC). Methods and Materials: Twenty patients who underwent IMRT for nondisseminated NPC at the Asan Medical Center between September 2001 and December 2003 were prospectively evaluated. Intensity-modulated radiotherapy was delivered with the 'step and shoot' SMART technique at prescribed doses of 72 Gy (2.4 Gy/day) to the gross tumor volume, 60 Gy (2 Gy/day) to the clinical target volume and metastatic nodal station, and 46 Gy (2 Gy/day) to the clinically negative neck region. Eighteen patients also received cisplatin once per week. Results: The median follow-up period was 27 months. Nineteen patients completed the treatment without interruption; the remaining patient interrupted treatment for 2 weeks owing to severe pharyngitis and malnutrition. Five patients (25%) had Radiation Therapy Oncology Group Grade 3 mucositis, whereas 9 (45%) had Grade 3 pharyngitis. Seven patients (35%) lost more than 10% of their pretreatment weight, whereas 11 (55%) required intravenous fluids and/or tube feeding. There was no Grade 3 or 4 xerostomia. All patients showed complete response. Two patients had distant metastases and locoregional recurrence, respectively. Conclusion: Intensity-modulated radiotherapy with the SMART boost technique allows parotid sparing, as shown clinically and by dosimetry, and might also be more effective biologically. A larger population of patients and a longer follow-up period are needed to evaluate ultimate tumor control and late toxicity.

  12. Outcomes of Postoperative Simultaneous Modulated Accelerated Radiotherapy for Head-and-Neck Squamous Cell Carcinoma

    SciTech Connect

    Moon, Sung Ho; Jung, Yuh-Seog; Ryu, Jun Sun; Choi, Sung Weon; Park, Joo Yong; Yun, Tak; Lee, Sang Hyun; Cho, Kwan Ho

    2011-09-01

    Purpose: To evaluate the treatment efficacy and toxicity of postoperative simultaneous modulated accelerated radiotherapy (SMART) for patients with head-and-neck squamous cell carcinoma (HNSCC). Methods and Materials: Between February 2003 and September 2008, 51 patients with histologically confirmed HNSCC received postoperative intensity-modulated radiotherapy (N = 33) or helical tomotherapy (N = 18) using SMART after curative surgical resection. The sites included were the oral cavity (OC), oropharynx (OP), larynx, and hypopharynx in 23, 20, 5, and 3 patients, respectively. Results: The median follow-up duration of all patients and surviving patients were 32 (range, 5-78 months) and 39 months (range, 9-77 months), respectively. The 3-year overall survival, cause-specific survival, disease-free survival, locoregional recurrence-free survival (LRRFS), and distant metastasis-free survival (DMFS) in all patients were 71%, 77%, 75%, 85%, and 82%, respectively. Although no significant difference in 3-year LRRFS were found between OC (82%) and OP (82%) carcinomas, the 3-year DMFS was worse in cases of OC (66%) carcinoma compared with OP carcinoma (95%; p = 0.0414). Acute Grade 3 dermatitis, mucositis, and esophagitis occurred in 10%, 10%, and 2% of patients, respectively. At the last follow-up, Grade 3 xerostomia was documented in 10% of the patients. Young age ({<=}40 years) (p < 0.001) and OC carcinoma primary (p = 0.0142) were poor risk factors on univariate analysis for DMFS. Conclusion: Postoperative SMART was observed to be effective and safe in patients with HNSCC.

  13. A volumetric approach to path-length measurements is essential when treating radiotherapy with modulated beams

    SciTech Connect

    Forde, Elizabeth; Booth, Jeremy; Leech, Michelle

    2014-07-01

    The established dosimetric benefits of intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy have lead to their increased use in prostate radiotherapy. Complimenting these techniques, volumetric image guidance has supported increased positional accuracy. In addition, 3-dimensional image guidance has also allowed for assessment of potential dosimetric variation that can be attributed to a deformation of either internal or external structures, such as rectal distension or body contour. Compounding these issues is the variation of tissue density through which the new field position passes and also the variation of dose across a modulated beam. Despite the growing level of interest in this area, there are only a limited number of articles that examine the effect of a variation in beam path length, particularly across a modulated field. IMRT and volumetric-modulated radiation therapy (VMAT) fields are dynamic in nature, and the dose gradient within these fields is variable. Assessment of variation of path length away from the beam's central axis and across the entire field is vital where there is considerable variation of dose within the field, such as IMRT and VMAT. In these cases, reliance on the traditional central axis to focus skin distances is no longer appropriate. This article discusses these more subtle challenges that may have a significant clinical effect if left unrecognized and undervalued.

  14. A review of stereotactic body radiotherapy – is volumetric modulated arc therapy the answer?

    SciTech Connect

    Sapkaroski, Daniel Osborne, Catherine; Knight, Kellie A

    2015-06-15

    Stereotactic body radiotherapy (SBRT) is a high precision radiotherapy technique used for the treatment of small to moderate extra-cranial tumours. Early studies utilising SBRT have shown favourable outcomes. However, major disadvantages of static field SBRT include long treatment times and toxicity complications. Volumetric modulated arc therapy (VMAT) and intensity modulated radiotherapy (IMRT) may potentially mitigate these disadvantages. This review aims to assess the feasibility of emerging VMAT and IMRT-based SBRT treatment techniques and qualify which offers the best outcome for patients, whilst identifying any emerging and advantageous SBRT planning trends. A review and synthesis of data from current literature up to September 2013 was conducted on EMBASE, Medline, PubMed, Science Direct, Proquest central, Google Scholar and the Cochrane Database of Systematic reviews. Only full text papers comparing VMAT and or IMRT and or Static SBRT were included. Ten papers were identified that evaluated the results of VMAT/IMRT SBRT. Five related to medically inoperable stage 1 and 2 non-small-cell lung cancer (NSCLC), three to spinal metastasis, one related to abdominal lymph node malignancies, with the final one looking at pancreatic adenocarcinoma. Overall treatment times with VMAT were reduced by 66–70% for lung, 46–58% for spine, 42% and 21% for lymph node and pancreatic metastasis respectively, planning constraints were met with several studies showing improved organs at risk sparing with IMRT/VMAT to static SBRT. Both IMRT and VMAT were able to meet all planning constraints in the studies reviewed, with VMAT offering the greatest treatment efficiency. Early clinical outcomes with VMAT and IMRT SBRT have demonstrated excellent local control and favourable survival outcomes.

  15. Intensity Modulated Radiotherapy Improves Target Coverage and Parotid Gland Sparing When Delivering Total Mucosal Irradiation in Patients With Squamous Cell Carcinoma of Head and Neck of Unknown Primary Site

    SciTech Connect

    Bhide, Shreerang Clark, Catherine; Harrington, Kevin; Nutting, Christopher M.

    2007-10-01

    Head and neck squamous cell carcinoma with occult primary site represents a controversial clinical problem. Conventional total mucosal irradiation (TMI) maximizes local control, but at the expense of xerostomia. IMRT has been shown to spare salivary tissue in head and cancer patients. This study has been performed to investigate the potential of IMRT to perform nodal and TMI and also allow parotid gland sparing in this patient group. Conventional radiotherapy (CRT) and IMRT plans were produced for six patients to treat the ipsilateral (involved) post-operative neck (PTV1) and the un-operated contralateral neck and mucosal axis (PTV2). Plans were produced with and without the inclusion of nasopharynx in the PTV2. The potential to improve target coverage and spare the parotid glands was investigated for the IMRT plans. There was no significant difference in the mean doses to the PTV1 using CRT and IMRT (59.7 and 60.0 respectively, p = 0.5). The maximum doses to PTV1 and PTV2 were lower for the IMRT technique as compared to CRT (P = 0.008 and P < 0.0001), respectively, and the minimum doses to PTV1 and PTV2 were significantly higher for IMRT as compared to CRT (P = 0.001 and P = 0.001), respectively, illustrating better dose homogeneity with IMRT. The mean dose to the parotid gland contralateral to PTV1 was significantly lower for IMRT (23.21 {+-} 0.7) as compared to CRT (50.5 {+-} 5.8) (P < 0.0001). There was a significant difference in parotid dose between plans with and without the inclusion of the nasopharynx. IMRT offers improved dose homogeneity in PTV1 and PTV2 and allows for parotid sparing.

  16. [Prostate cancer external beam radiotherapy].

    PubMed

    de Crevoisier, R; Pommier, P; Latorzeff, I; Chapet, O; Chauvet, B; Hennequin, C

    2016-09-01

    The prostate external beam radiotherapy techniques are described, when irradiating the prostate or after prostatectomy, with and without pelvic lymph nodes. The following parts are presented: indications of radiotherapy, total dose and fractionation, planning CT image acquisition, volume of interest delineation (target volumes and organs at risk) and margins, Intensity modulated radiotherapy planning and corresponding dose-volume constraints, and finally Image guided radiotherapy. PMID:27516051

  17. Film Dosimetry for Intensity Modulated Radiation Therapy

    NASA Astrophysics Data System (ADS)

    Benites-Rengifo, J.; Martínez-Dávalos, A.; Celis, M.; Lárraga, J.

    2004-09-01

    Intensity Modulated Radiation Therapy (IMRT) is an oncology treatment technique that employs non-uniform beam intensities to deliver highly conformal radiation to the targets while minimizing doses to normal tissues and critical organs. A key element for a successful clinical implementation of IMRT is establishing a dosimetric verification process that can ensure that delivered doses are consistent with calculated ones for each patient. To this end we are developing a fast quality control procedure, based on film dosimetry techniques, to be applied to the 6 MV Novalis linear accelerator for IMRT of the Instituto Nacional de Neurología y Neurocirugía (INNN) in Mexico City. The procedure includes measurements of individual fluence maps for a limited number of fields and dose distributions in 3D using extended dose-range radiographic film. However, the film response to radiation might depend on depth, energy and field size, and therefore compromise the accuracy of measurements. In this work we present a study of the dependence of Kodak EDR2 film's response on the depth, field size and energy, compared with those of Kodak XV2 film. The first aim is to devise a fast and accurate method to determine the calibration curve of film (optical density vs. doses) commonly called a sensitometric curve. This was accomplished by using three types of irradiation techniques: Step-and-shoot, dynamic and static fields.

  18. Dose-escalation using intensity-modulated radiotherapy for prostate cancer - evaluation of quality of life with and without 18F-choline PET-CT detected simultaneous integrated boost

    PubMed Central

    2012-01-01

    Background In comparison to the conventional whole-prostate dose escalation, an integrated boost to the macroscopic malignant lesion might potentially improve tumor control rates without increasing toxicity. Quality of life after radiotherapy (RT) with vs. without 18F-choline PET-CT detected simultaneous integrated boost (SIB) was prospectively evaluated in this study. Methods Whole body image acquisition in supine patient position followed 1 h after injection of 178-355MBq 18F-choline. SIB was defined by a tumor-to-background uptake value ratio > 2 (GTVPET). A dose of 76Gy was prescribed to the prostate (PTVprostate) in 2Gy fractions, with or without SIB up to 80Gy. Patients treated with (n = 46) vs. without (n = 21) SIB were surveyed prospectively before (A), at the last day of RT (B) and a median time of two (C) and 19 month (D) after RT to compare QoL changes applying a validated questionnaire (EPIC - expanded prostate cancer index composite). Results With a median cut-off standard uptake value (SUV) of 3, a median GTVPET of 4.0 cm3 and PTVboost (GTVPET with margins) of 17.3 cm3 was defined. No significant differences were found for patients treated with vs. without SIB regarding urinary and bowel QoL changes at times B, C and D (mean differences ≤3 points for all comparisons). Significantly decreasing acute urinary and bowel score changes (mean changes > 5 points in comparison to baseline level at time A) were found for patients with and without SIB. However, long-term urinary and bowel QoL (time D) did not differ relative to baseline levels - with mean urinary and bowel function score changes < 3 points in both groups (median changes = 0 points). Only sexual function scores decreased significantly (> 5 points) at time D. Conclusions Treatment planning with 18F-choline PET-CT allows a dose escalation to a macroscopic intraprostatic lesion without significantly increasing toxicity. PMID:22289620

  19. Photon energy-modulated radiotherapy: Monte Carlo simulation and treatment planning study

    SciTech Connect

    Park, Jong Min; Kim, Jung-in; Heon Choi, Chang; Chie, Eui Kyu; Kim, Il Han; Ye, Sung-Joon

    2012-03-15

    Purpose: To demonstrate the feasibility of photon energy-modulated radiotherapy during beam-on time. Methods: A cylindrical device made of aluminum was conceptually proposed as an energy modulator. The frame of the device was connected with 20 tubes through which mercury could be injected or drained to adjust the thickness of mercury along the beam axis. In Monte Carlo (MC) simulations, a flattening filter of 6 or 10 MV linac was replaced with the device. The thickness of mercury inside the device varied from 0 to 40 mm at the field sizes of 5 x 5 cm{sup 2} (FS5), 10 x 10 cm{sup 2} (FS10), and 20 x 20 cm{sup 2} (FS20). At least 5 billion histories were followed for each simulation to create phase space files at 100 cm source to surface distance (SSD). In-water beam data were acquired by additional MC simulations using the above phase space files. A treatment planning system (TPS) was commissioned to generate a virtual machine using the MC-generated beam data. Intensity modulated radiation therapy (IMRT) plans for six clinical cases were generated using conventional 6 MV, 6 MV flattening filter free, and energy-modulated photon beams of the virtual machine. Results: As increasing the thickness of mercury, Percentage depth doses (PDD) of modulated 6 and 10 MV after the depth of dose maximum were continuously increased. The amount of PDD increase at the depth of 10 and 20 cm for modulated 6 MV was 4.8% and 5.2% at FS5, 3.9% and 5.0% at FS10 and 3.2%-4.9% at FS20 as increasing the thickness of mercury from 0 to 20 mm. The same for modulated 10 MV was 4.5% and 5.0% at FS5, 3.8% and 4.7% at FS10 and 4.1% and 4.8% at FS20 as increasing the thickness of mercury from 0 to 25 mm. The outputs of modulated 6 MV with 20 mm mercury and of modulated 10 MV with 25 mm mercury were reduced into 30%, and 56% of conventional linac, respectively. The energy-modulated IMRT plans had less integral doses than 6 MV IMRT or 6 MV flattening filter free plans for tumors located in the

  20. Single-energy intensity modulated proton therapy

    NASA Astrophysics Data System (ADS)

    Farace, Paolo; Righetto, Roberto; Cianchetti, Marco

    2015-09-01

    In this note, an intensity modulated proton therapy (IMPT) technique, based on the use of high single-energy (SE-IMPT) pencil beams, is described. The method uses only the highest system energy (226 MeV) and only lateral penumbra to produce dose gradient, as in photon therapy. In the study, after a preliminary analysis of the width of proton pencil beam penumbras at different depths, SE-IMPT was compared with conventional IMPT in a phantom containing titanium inserts and in a patient, affected by a spinal chordoma with fixation rods. It was shown that SE-IMPT has the potential to produce a sharp dose gradient and that it is not affected by the uncertainties produced by metal implants crossed by the proton beams. Moreover, in the chordoma patient, target coverage and organ at risk sparing of the SE-IMPT plan resulted comparable to that of the less reliable conventional IMPT technique. Robustness analysis confirmed that SE-IMPT was not affected by range errors, which can drastically affect the IMPT plan. When accepting a low-dose spread as in modern photon techniques, SE-IMPT could be an option for the treatment of lesions (e.g. cervical bone tumours) where steep dose gradient could improve curability, and where range uncertainty, due for example to the presence of metal implants, hampers conventional IMPT.

  1. Single-energy intensity modulated proton therapy.

    PubMed

    Farace, Paolo; Righetto, Roberto; Cianchetti, Marco

    2015-10-01

    In this note, an intensity modulated proton therapy (IMPT) technique, based on the use of high single-energy (SE-IMPT) pencil beams, is described.The method uses only the highest system energy (226 MeV) and only lateral penumbra to produce dose gradient, as in photon therapy. In the study, after a preliminary analysis of the width of proton pencil beam penumbras at different depths, SE-IMPT was compared with conventional IMPT in a phantom containing titanium inserts and in a patient, affected by a spinal chordoma with fixation rods.It was shown that SE-IMPT has the potential to produce a sharp dose gradient and that it is not affected by the uncertainties produced by metal implants crossed by the proton beams. Moreover, in the chordoma patient, target coverage and organ at risk sparing of the SE-IMPT plan resulted comparable to that of the less reliable conventional IMPT technique. Robustness analysis confirmed that SE-IMPT was not affected by range errors, which can drastically affect the IMPT plan.When accepting a low-dose spread as in modern photon techniques, SE-IMPT could be an option for the treatment of lesions (e.g. cervical bone tumours) where steep dose gradient could improve curability, and where range uncertainty, due for example to the presence of metal implants, hampers conventional IMPT. PMID:26352616

  2. Analysis of simultaneous modulated accelerated radiotherapy (SMART) for nasopharyngeal carcinomas

    PubMed Central

    Tang, Jian Min; Ma, Xiu Mei; Hou, Yan Li; Dai, Li Yan; Cao, Hong Bin; Ye, Ming; Bai, Yong Rui

    2014-01-01

    The purpose of this study was to analyze the clinical outcomes of simultaneous modulated accelerated radiotherapy (SMART) in patients with nasopharyngeal carcinoma (NPC). A total of 97 patients who underwent SMART for NPC between August 2005 and November 2011 were evaluated. The prescribed dose was 69.9 Gy/30 fractions at 2.33 Gy/fraction to the primary gross tumor volume (PGTV) including the nasopharynx gross target volume and the positive neck lymph nodes, and 60 Gy/30 fraction at 2.0 Gy/fraction to the PCTV1; 54 Gy/30 fractions at 1.8 Gy/fraction was given to the PCTV2. Among 59 patients with local advanced disease, 31 patients received concurrent chemoradiotherapy (chemo-RT) with a regimen consisting of 135 mg/m2 paclitaxel on Day 1 and 25 mg/m2 cisplatin on Days 1–3. The median follow-up period was 42 months. The local control rate (LCR), distant metastases-free survival (DMFS) and overall survival (OS) rates were 93.3%, 90.3% and 91.6% at 3 years, and 87.6%, 87.9% and 85.7% at 5 years, respectively. There was no significant difference in outcome with respect to these three indicators for Stage III and IV disease treated with/without concurrent chemoradiotherapy (P > 0.05). Acute toxicities included Grade 3 mucositis, skin desquamation, and leucopenia, which occurred in 78 (80.4%), 8 (8.2%), and 45 (46.4%) patients, respectively. No patient had a Grade 3–4 late toxicity. SMART was associated with a favorable outcome for NPC with acceptable toxicity. The local-regional control was excellent but distant metastasis remains the main risk. The combination of SMART and chemotherapy needs to be optimized through further studies to enhance outcomes for locally advanced diseases. PMID:24614820

  3. 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

    SciTech Connect

    Yi, Sun K.; Mak, Walter; Yang, Claus C.; Liu Tianxiao; Cui Jing; Chen, Allen M.; Purdy, James A.; Monjazeb, Arta M.; Do, Ly

    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.

  4. 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

    SciTech Connect

    Vergalasova, I; Mowery, Y; Yoo, D; Brizel, D; Das, S

    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

  5. Trajectory optimization for dynamic couch rotation during volumetric modulated arc radiotherapy

    NASA Astrophysics Data System (ADS)

    Smyth, Gregory; Bamber, Jeffrey C.; Evans, Philip M.; Bedford, James L.

    2013-11-01

    Non-coplanar radiation beams are often used in three-dimensional conformal and intensity modulated radiotherapy to reduce dose to organs at risk (OAR) by geometric avoidance. In volumetric modulated arc radiotherapy (VMAT) non-coplanar geometries are generally achieved by applying patient couch rotations to single or multiple full or partial arcs. This paper presents a trajectory optimization method for a non-coplanar technique, dynamic couch rotation during VMAT (DCR-VMAT), which combines ray tracing with a graph search algorithm. Four clinical test cases (partial breast, brain, prostate only, and prostate and pelvic nodes) were used to evaluate the potential OAR sparing for trajectory-optimized DCR-VMAT plans, compared with standard coplanar VMAT. In each case, ray tracing was performed and a cost map reflecting the number of OAR voxels intersected for each potential source position was generated. The least-cost path through the cost map, corresponding to an optimal DCR-VMAT trajectory, was determined using Dijkstra’s algorithm. Results show that trajectory optimization can reduce dose to specified OARs for plans otherwise comparable to conventional coplanar VMAT techniques. For the partial breast case, the mean heart dose was reduced by 53%. In the brain case, the maximum lens doses were reduced by 61% (left) and 77% (right) and the globes by 37% (left) and 40% (right). Bowel mean dose was reduced by 15% in the prostate only case. For the prostate and pelvic nodes case, the bowel V50 Gy and V60 Gy were reduced by 9% and 45% respectively. Future work will involve further development of the algorithm and assessment of its performance over a larger number of cases in site-specific cohorts.

  6. Light-intensity modulator withstands high heat fluxes

    NASA Technical Reports Server (NTRS)

    Maples, H. G.; Strass, H. K.

    1966-01-01

    Mechanism modulates and controls the intensity of luminous radiation in light beams associated with high-intensity heat flux. This modulator incorporates two fluid-cooled, externally grooved, contracting metal cylinders which when rotated about their longitudinal axes present a circular aperture of varying size depending on the degree of rotation.

  7. Robust optimization of intensity modulated proton therapy

    SciTech Connect

    Liu Wei; Zhang Xiaodong; Li Yupeng; Mohan, Radhe

    2012-02-15

    Purpose: Intensity modulated proton therapy (IMPT) is highly sensitive to range uncertainties and uncertainties caused by setup variation. The conventional inverse treatment planning of IMPT optimized based on the planning target volume (PTV) is not often sufficient to ensure robustness of treatment plans. In this paper, a method that takes the uncertainties into account during plan optimization is used to mitigate the influence of uncertainties in IMPT. Methods: The authors use the so-called ''worst-case robust optimization'' to render IMPT plans robust in the face of uncertainties. For each iteration, nine different dose distributions are computed--one each for {+-} setup uncertainties along anteroposterior (A-P), lateral (R-L) and superior-inferior (S-I) directions, for {+-} range uncertainty, and the nominal dose distribution. The worst-case dose distribution is obtained by assigning the lowest dose among the nine doses to each voxel in the clinical target volume (CTV) and the highest dose to each voxel outside the CTV. Conceptually, the use of worst-case dose distribution is similar to the dose distribution achieved based on the use of PTV in traditional planning. The objective function value for a given iteration is computed using this worst-case dose distribution. The objective function used has been extended to further constrain the target dose inhomogeneity. Results: The worst-case robust optimization method is applied to a lung case, a skull base case, and a prostate case. Compared with IMPT plans optimized using conventional methods based on the PTV, our method yields plans that are considerably less sensitive to range and setup uncertainties. An interesting finding of the work presented here is that, in addition to reducing sensitivity to uncertainties, robust optimization also leads to improved optimality of treatment plans compared to the PTV-based optimization. This is reflected in reduction in plan scores and in the lower normal tissue doses for the

  8. Radiotherapy of Cervical Cancer.

    PubMed

    Vordermark, Dirk

    2016-01-01

    Curative-intent radical radiotherapy of cervical cancer consists of external-beam radiotherapy, brachytherapy, and concomitant chemotherapy with cisplatin. For each element, new developments aim to improve tumor control rates or treatment tolerance. Intensity-modulated radiotherapy (IMRT) has been shown to reduce gastrointestinal toxicity and can be used to selectively increase the radiotherapy dose. Individualized, image-guided brachytherapy enables better adaptation of high-dose volumes to the tumor extension. Intensification of concomitant or sequential systemic therapy is under evaluation. PMID:27614991

  9. Synthetic single crystal diamond dosimeters for Intensity Modulated Radiation Therapy applications

    NASA Astrophysics Data System (ADS)

    Almaviva, S.; Ciancaglioni, I.; Consorti, R.; De Notaristefani, F.; Manfredotti, C.; Marinelli, Marco; Milani, E.; Petrucci, A.; Prestopino, G.; Verona, C.; Verona-Rinati, G.

    2009-09-01

    A synthetic single crystal diamond Schottky diode, in a p-type/intrinsic/metal structure, deposited by Chemical Vapour Deposition (CVD) and operating in photovoltaic regime, with no external bias voltage applied, was tested as a dosimeter for Intensity Modulated Radiation Therapy (IMRT) applications. The device response was compared with dose measurements from two commercial ionization chambers and a 2D diode array in an IMRT prostate cancer treatment plan. The obtained results indicate that CVD synthetic single crystal diamond-based dosimeters can successfully be used for highly conformed radiotherapy and IMRT dosimetry, due to their small size and high sensitivity per unit volume.

  10. Pre-treatment radiotherapy dose verification using Monte Carlo doselet modulation in a spherical phantom

    NASA Astrophysics Data System (ADS)

    Townson, Reid W.; Zavgorodni, Sergei

    2014-04-01

    Due to the increasing complexity of radiotherapy delivery, accurate dose verification has become an essential part of the clinical treatment process. The purpose of this work was to develop a pre-treatment verification technique capable of quickly reconstructing 3D dose distributions from both coplanar and non-coplanar treatments. For each treatment field, electronic portal images were taken in non-transmission mode (with no patient in the beam) allowing the derivation of the delivered fluence maps. The dose reconstruction was then performed in a spherical water phantom by modulating and summing the Monte Carlo (MC) doselets, defined on a spherical co-ordinate system, and pre-calculated from azimuthally symmetric fluence above the jaws. The technique, called the spherical doselet modulation (SDM) method, essentially eliminates the statistical uncertainty of the MC dose calculations by exploiting the azimuthal symmetry in both a patient-independent phase-space and in a virtual spherical water phantom. For example, this symmetry allowed the number of doselets necessary for dose reconstruction to be reduced by a factor of ˜250. In this work, only 51 radially binned doselets were used (each generated from all particles in a given annulus of the phase-space, azimuthally redistributed into a small cylindrical sector). The SDM method mitigates the most computationally intensive part of this type of dose reconstruction--reading, weighting and summing dose matrices. The accuracy of the system was tested against MC calculations as well as our previously reported phase-space modulation method, using a series of open field and IMRT cases. The mean chi- and gamma-test 3%/3 mm success rates of the SDM method were 98.6% and 99.5%, respectively, when compared to full MC simulation. The total calculation time was 96 s per treatment field on a single processor core.

  11. [Radiotherapy for Thyroid Cancer].

    PubMed

    Jingu, Keiichi; Maruoka, Shin; Umezawa, Rei; Takahashi, Noriyoshi

    2015-06-01

    Radioactive 131I therapy for differentiated thyroid cancer has been used since the 1940s and is an established and effective treatment. In contrast, external beam radiotherapy (EBRT) was considered to be effective for achieving local control but not for prolonging survival. Although clinicians were hesitant to administer EBRT owing to the potential radiation-induced adverse effects of 2 dimensional (2D)-radiotherapy until 2000, it is expected that adverse effects will be reduced and treatment efficacy improved through the introduction of more advanced techniques for delivering radiation (eg, 3D-radiotherapy and intensity modulated radiotherapy [IMRT]). The prognosis of undifferentiated thyroid cancer is known to be extremely bad, although in very rare cases, multimodality therapy (total or subtotal resection, chemotherapy, and radiotherapy) has allowed long-term survival. Here, we report the preliminary results of using hypofractionated radiotherapy for undifferentiated thyroid cancer in our institution. PMID:26199238

  12. Effect of reducing temporal intensity modulations on sentence intelligibility.

    PubMed

    Noordhoek, I M; Drullman, R

    1997-01-01

    Modulations in the temporal intensity envelope of 24 1/4-octave bands were reduced by proportionally raising the troughs and lowering the peaks relative to the mean intensity in each band. The effect on intelligibility of various degrees of modulation reduction was investigated by measuring the speech-reception threshold (SRT) in noise. For conditions of severe modulation reduction, the number of correctly received sentences in quiet was scored. The effect of this deterministic modulation reduction was compared to the effect of stochastic modulation reduction obtained with addition of noise. Results for 12 normal-hearing subjects show that in the case of deterministic modulation reduction, intelligibility is reduced to 50% when the modulation-transfer factor equals