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Sample records for beam radiation boost

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

    International Nuclear Information System (INIS)

    This study aims to determine the optimal beam design among various combinations of field numbers and beam trajectories for intensity-modulated radiation therapy (IMRT) with simultaneous integrated boost (SIB) technique for the treatment of nasopharyngeal cancer (NPC). We used 10 fields with gantry angles of 155°, 130°, 75°, 25°, 0° L, 0° R, 335°, 285°, 230°, and 205° denoted as F10. To decrease doses in the spinal cord, the F10 technique was designed by featuring 2 pairs of split-opposed beam fields at 155° to 335° and 205° to 25°, as well as one pair of manually split beam fields at 0°. The F10 technique was compared with 4 other common field arrangements: F7E, 7 fields with 50° equally spaced gantry angles; F7, the basis of F10 with 155°, 130°, 75°, 0°, 285°, 230°, and 205°; F9E, 9 fields with 40° equally spaced gantry angles; and FP, 7 posterior fields with 180°, 150°, 120°, 90°, 270°, 240°, and 210°. For each individual case of 10 patients, the customized constraints derived after optimization with the standard F10 technique were applied to 4 other field arrangements. The 4 new optimized plans of each individual case were normalized to achieve the same coverage of planning target volume (PTV)63 Gy as that of the standard F10 technique. The F10 field arrangement exhibited the best coverage in PTV70 Gy and the least mean dose in the trachea-esophagus region. Furthermore, the F10 field arrangement demonstrated the highest level of conformity in the low-dose region and the least monitor unit. The F10 field arrangement performed more outstandingly than the other field arrangements in PTV70 Gy coverage and spared the central organ. This arrangement also exhibited the highest conformity and delivery efficiency. The F10 technique is recommended as the standard beam geometry for the SIB-IMRT of NPC

  2. The Beaming Pattern of Doppler Boosted Thermal Annihilation Radiation: Application to MeV Blazars

    OpenAIRE

    Skibo, J. G.; Dermer, C. D.; Schlickeiser, R.

    1997-01-01

    The beaming pattern of thermal annihilation radiation is broader than the beaming pattern produced by isotropic nonthermal electrons and positrons in the jets of radio-emitting active galactic nuclei which Compton scatter photons from an external isotropic radiation field. Thus blueshifted thermal annihilation radiation can provide the dominant contribution to the high-energy radiation spectrum at observing angles theta > 1/Gamma, where Gamma is the bulk Lorentz factor of the outflowing plasm...

  3. PDR brachytherapy with flexible implants for interstitial boost after breast-conserving surgery and external beam radiation therapy

    International Nuclear Information System (INIS)

    Background and purpose: For radiobiological reasons the new concept of pulsed dose rate (PDR) brachytherapy seems to be suitable to replace traditional CLDR brachytherapy with line sources. PDR brachytherapy using a stepping source seems to be particularly suitable for the interstitial boost of breast carcinoma after breast-conserving surgery and external beam irradiation since in these cases the exact adjustment of the active lengths is essential in order to prevent unwanted skin dose and consequential unfavorable cosmetic results. The purpose of this study was to assess the feasibility and morbidity of a PDR boost with flexible breast implants. Materials and methods: Sixty-five high risk patients were treated with an interstitial PDR boost. The criteria for an interstitial boost were positive margin or close margin, extensive intraductal component (EIC), intralymphatic extension, lobular carcinoma, T2 tumors and high nuclear grade (GIII). Dose calculation and specification were performed following the rules of the Paris system. The dose per pulse was 1 Gy. The pulse pauses were kept constant at 1 h. A geometrically optimized dose distribution was used for all patients. The treatment schedule was 50 Gy external beam to the whole breast and 20 Gy boost. PDR irradiations were carried out with a nominal 37 GBq 192-Ir source. Results: The median follow-up was 30 months (minimum 12 months, maximum 54 months). Sixty percent of the patients judged their cosmetic result as excellent, 27% judged it as good, 11% judged it as fair and 2% judged it as poor. Eighty-six percent of the patients had no radiogenous skin changes in the boost area. In 11% of patients minimal punctiform telangiectasia appeared at single puncture sites. In 3% ((2(65))) of patients planar telangiectasia appeared on the medial side of the implant. The rate of isolated local recurrences was 1.5%. In most cases geometrical volume optimization (GVO) yields improved dose distributions with respect to

  4. External beam radiation therapy and a low-dose-rate brachytherapy boost without or with androgen deprivation therapy for prostate cancer

    International Nuclear Information System (INIS)

    Purpose: To assess outcomes with external beam radiation therapy (EBRT) and a low-dose-rate (LDR) brachytherapy boost without or with androgen deprivation therapy (ADT) for prostate cancer. Materials and Methods: From January 2001 through August 2011, 120 intermediate-risk or high-risk prostate cancer patients were treated with EBRT to a total dose of 4,500 cGy in 25 daily fractions and a palladium-103 LDR brachytherapy boost of 10,000 cGy (n = 90) or an iodine-125 LDR brachytherapy boost of 11,000 cGy (n = 30). ADT, consisting of a gonadotropin-releasing hormone agonist ± an anti-androgen, was administered to 29/92 (32%) intermediate-risk patients for a median duration of 4 months and 26/28 (93%) high-risk patients for a median duration of 28 months. Results: Median follow-up was 5.2 years (range, 1.1-12.8 years). There was no statistically-significant difference in biochemical disease-free survival (bDFS), distant metastasis-free survival (DMFS), or overall survival (OS) without or with ADT. Also, there was no statistically-significant difference in bDFS, DMFS, or OS with a palladium-103 vs. an iodine-125 LDR brachytherapy boost. Conclusions: There was no statistically-significant difference in outcomes with the addition of ADT, though the power of the current study was limited. The Radiation Therapy Oncology Group 0815 and 0924 phase III trials, which have accrual targets of more than 1,500 men, will help to clarify the role ADT in locally-advanced prostate cancer patients treated with EBRT and a brachytherapy boost. Palladium-103 and iodine-125 provide similar bDFS, DMFS, and OS. (author)

  5. External beam radiation therapy and a low-dose-rate brachytherapy boost without or with androgen deprivation therapy for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Strom, Tobin J.; Hutchinson, Sean Z.; Shrinath, Kushagra; Cruz, Alex A.; Figura, Nicholas B.; Nethers, Kevin; Biagioli, Matthew C.; Fernandez, Daniel C.; Heysek, Randy V.; Wilder, Richard B., E-mail: richard.wilder@moffitt.org [Department of Radiation Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL (United States)

    2014-07-15

    Purpose: To assess outcomes with external beam radiation therapy (EBRT) and a low-dose-rate (LDR) brachytherapy boost without or with androgen deprivation therapy (ADT) for prostate cancer. Materials and Methods: From January 2001 through August 2011, 120 intermediate-risk or high-risk prostate cancer patients were treated with EBRT to a total dose of 4,500 cGy in 25 daily fractions and a palladium-103 LDR brachytherapy boost of 10,000 cGy (n = 90) or an iodine-125 LDR brachytherapy boost of 11,000 cGy (n = 30). ADT, consisting of a gonadotropin-releasing hormone agonist ± an anti-androgen, was administered to 29/92 (32%) intermediate-risk patients for a median duration of 4 months and 26/28 (93%) high-risk patients for a median duration of 28 months. Results: Median follow-up was 5.2 years (range, 1.1-12.8 years). There was no statistically-significant difference in biochemical disease-free survival (bDFS), distant metastasis-free survival (DMFS), or overall survival (OS) without or with ADT. Also, there was no statistically-significant difference in bDFS, DMFS, or OS with a palladium-103 vs. an iodine-125 LDR brachytherapy boost. Conclusions: There was no statistically-significant difference in outcomes with the addition of ADT, though the power of the current study was limited. The Radiation Therapy Oncology Group 0815 and 0924 phase III trials, which have accrual targets of more than 1,500 men, will help to clarify the role ADT in locally-advanced prostate cancer patients treated with EBRT and a brachytherapy boost. Palladium-103 and iodine-125 provide similar bDFS, DMFS, and OS. (author)

  6. Combination External Beam Radiation and Brachytherapy Boost With Androgen Suppression for Treatment of Intermediate-Risk Prostate Cancer: An Initial Report of CALGB 99809

    International Nuclear Information System (INIS)

    Purpose: Transperineal prostate brachytherapy (TPPB) can be used with external beam radiation therapy (EBRT) to provide a high-dose conformal boost to the prostate. The results of a multicenter Phase II trial assessing safety of combination of EBRT and TPPB boost with androgen suppression (AST) in treatment of intermediate-risk prostate cancer are present here. Materials and Methods: Patients had intermediate-risk prostate cancer. Six months of AST was administered. EBRT to the prostate and seminal vesicles was administered to 45Gy followed by TPPB using either 125I or 103Pd to deliver an additional 100Gy or 90Gy. Toxicity was graded using the National Cancer Institute CTC version 2 and the Radiation Therapy Oncology Group late radiation morbidity scoring systems. Results: Sixty-three patients were enrolled. Median follow-up was 38 months. Side effects of AST including sexual dysfunction and vasomotor symptoms were commonly observed. Apart from erectile dysfunction, short-term Grade 2 and 3 toxicity was noted in 21% and 7%, primarily genitourinary related. Long-term Grade 2 and 3 toxicities were noted in 13% and 3%. Two patients had Grade 3 dysuria that resolved with longer follow-up. The most common Grade 2 long-term toxicity was urinary frequency (5%). No biochemical or clinical evidence of progression was noted for the entire cohort. Conclusions: In a cooperative group setting, combination EBRT and TPPB boost with 6 months of AST was generally well tolerated with expected genitourinary and gastrointestinal toxicities. Further follow-up will be required to fully assess long-term toxicity and cancer control

  7. Anticipated Intraoperative Electron Beam Boost, External Beam Radiation Therapy, and Limb-Sparing Surgical Resection for Patients with Pediatric Soft-Tissue Sarcomas of the Extremity: A Multicentric Pooled Analysis of Long-Term Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Sole, Claudio V., E-mail: cvsole@uc.cl [Department of Oncology, Hospital General Universitario Gregorio Marañón, Madrid (Spain); School of Medicine, Complutense University, Madrid (Spain); Service of Radiation Oncology, Instituto de Radiomedicina, Santiago (Chile); Calvo, Felipe A. [Department of Oncology, Hospital General Universitario Gregorio Marañón, Madrid (Spain); School of Medicine, Complutense University, Madrid (Spain); Polo, Alfredo [Service of Radiation Oncology, Hospital Universitario Ramón y Cajal, Madrid (Spain); Cambeiro, Mauricio [Service of Radiation Oncology, Clínica Universidad de Navarra, Pamplona (Spain); Alvarez, Ana; Gonzalez, Carmen [Service of Radiation Oncology, Hospital General Universitario Gregorio Marañón, Madrid (Spain); Gonzalez, Jose [Service of Pediatric Orthopedics and Traumatology, Hospital General Universitario Gregorio Marañón, Madrid (Spain); San Julian, Mikel [Service of Orthopedics and Traumatology, Clínica Universidad de Navarra, Pamplona (Spain); Martinez-Monge, Rafael [Service of Radiation Oncology, Clínica Universidad de Navarra, Pamplona (Spain)

    2014-09-01

    Purpose: To perform a joint analysis of data from 3 contributing centers within the intraoperative electron-beam radiation therapy (IOERT)-Spanish program, to determine the potential of IOERT as an anticipated boost before external beam radiation therapy in the multidisciplinary treatment of pediatric extremity soft-tissue sarcomas. Methods and Materials: From June 1993 to May 2013, 62 patients (aged <21 years) with a histologic diagnosis of primary extremity soft-tissue sarcoma with absence of distant metastases, undergoing limb-sparing grossly resected surgery, external beam radiation therapy (median dose 40 Gy) and IOERT (median dose 10 Gy) were considered eligible for this analysis. Results: After a median follow-up of 66 months (range, 4-235 months), 10-year local control, disease-free survival, and overall survival was 85%, 76%, and 81%, respectively. In multivariate analysis after adjustment for other covariates, tumor size >5 cm (P=.04) and R1 margin status (P=.04) remained significantly associated with local relapse. In regard to overall survival only margin status (P=.04) retained association on multivariate analysis. Ten patients (16%) reported severe chronic toxicity events (all grade 3). Conclusions: An anticipated IOERT boost allowed for external beam radiation therapy dose reduction, with high local control and acceptably low toxicity rates. The combined radiosurgical approach needs to be tested in a prospective trial to confirm these results.

  8. Anticipated Intraoperative Electron Beam Boost, External Beam Radiation Therapy, and Limb-Sparing Surgical Resection for Patients with Pediatric Soft-Tissue Sarcomas of the Extremity: A Multicentric Pooled Analysis of Long-Term Outcomes

    International Nuclear Information System (INIS)

    Purpose: To perform a joint analysis of data from 3 contributing centers within the intraoperative electron-beam radiation therapy (IOERT)-Spanish program, to determine the potential of IOERT as an anticipated boost before external beam radiation therapy in the multidisciplinary treatment of pediatric extremity soft-tissue sarcomas. Methods and Materials: From June 1993 to May 2013, 62 patients (aged <21 years) with a histologic diagnosis of primary extremity soft-tissue sarcoma with absence of distant metastases, undergoing limb-sparing grossly resected surgery, external beam radiation therapy (median dose 40 Gy) and IOERT (median dose 10 Gy) were considered eligible for this analysis. Results: After a median follow-up of 66 months (range, 4-235 months), 10-year local control, disease-free survival, and overall survival was 85%, 76%, and 81%, respectively. In multivariate analysis after adjustment for other covariates, tumor size >5 cm (P=.04) and R1 margin status (P=.04) remained significantly associated with local relapse. In regard to overall survival only margin status (P=.04) retained association on multivariate analysis. Ten patients (16%) reported severe chronic toxicity events (all grade 3). Conclusions: An anticipated IOERT boost allowed for external beam radiation therapy dose reduction, with high local control and acceptably low toxicity rates. The combined radiosurgical approach needs to be tested in a prospective trial to confirm these results

  9. To analyze the impact of intracavitary brachytherapy as boost radiation after external beam radiotherapy in carcinoma of the external auditory canal and middle ear: A retrospective analysis

    Directory of Open Access Journals (Sweden)

    Dinesh K Badakh

    2014-01-01

    Conclusion: ICBT as a boost after EBRT has got a positive impact on the OS. In conclusion, our results demonstrate that radical radiation therapy (EBRT and ICBT is the treatment of choice for stage T2, carcinoma of EACMA.

  10. Early observed transient prostate-specific antigen elevations on a pilot study of external beam radiation therapy and fractionated MRI guided High Dose Rate brachytherapy boost

    International Nuclear Information System (INIS)

    To report early observation of transient PSA elevations on this pilot study of external beam radiation therapy and magnetic resonance imaging (MRI) guided high dose rate (HDR) brachytherapy boost. Eleven patients with intermediate-risk and high-risk localized prostate cancer received MRI guided HDR brachytherapy (10.5 Gy each fraction) before and after a course of external beam radiotherapy (46 Gy). Two patients continued on hormones during follow-up and were censored for this analysis. Four patients discontinued hormone therapy after RT. Five patients did not receive hormones. PSA bounce is defined as a rise in PSA values with a subsequent fall below the nadir value or to below 20% of the maximum PSA level. Six previously published definitions of biochemical failure to distinguish true failure from were tested: definition 1, rise >0.2 ng/mL; definition 2, rise >0.4 ng/mL; definition 3, rise >35% of previous value; definition 4, ASTRO defined guidelines, definition 5 nadir + 2 ng/ml, and definition 6, nadir + 3 ng/ml. Median follow-up was 24 months (range 18–36 mo). During follow-up, the incidence of transient PSA elevation was: 55% for definition 1, 44% for definition 2, 55% for definition 3, 33% for definition 4, 11% for definition 5, and 11% for definition 6. We observed a substantial incidence of transient elevations in PSA following combined external beam radiation and HDR brachytherapy for prostate cancer. Such elevations seem to be self-limited and should not trigger initiation of salvage therapies. No definition of failure was completely predictive

  11. Direct 2-Arm Comparison Shows Benefit of High-Dose-Rate Brachytherapy Boost vs External Beam Radiation Therapy Alone for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Khor, Richard [Division of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, and University of Melbourne, Melbourne (Australia); Duchesne, Gillian [Division of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, and University of Melbourne, Melbourne (Australia); Monash University, Melbourne (Australia); Tai, Keen-Hun; Foroudi, Farshad; Chander, Sarat; Van Dyk, Sylvia; Garth, Margaret [Division of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, and University of Melbourne, Melbourne (Australia); Williams, Scott, E-mail: Scott.Williams@petermac.org [Division of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, and University of Melbourne, Melbourne (Australia)

    2013-03-01

    Purpose: To evaluate the outcomes of patients treated for intermediate- and high-risk prostate cancer with a single schedule of either external beam radiation therapy (EBRT) and high-dose-rate brachytherapy (HDRB) boost or EBRT alone. Methods and Materials: From 2001-2006, 344 patients received EBRT with HDRB boost for definitive treatment of intermediate- or high-risk prostate cancer. The prescribed EBRT dose was 46 Gy in 23 fractions, with a HDR boost of 19.5 Gy in 3 fractions. This cohort was compared to a contemporaneously treated cohort who received EBRT to 74 Gy in 37 fractions, using a matched pair analysis. Three-dimensional conformal EBRT was used. Matching was performed using a propensity score matching technique. High-risk patients constituted 41% of the matched cohorts. Five-year clinical and biochemical outcomes were analyzed. Results: Initial significant differences in prognostic indicators between the unmatched treatment cohorts were rendered negligible after matching, providing a total of 688 patients. Median biochemical follow-up was 60.5 months. The 5-year freedom from biochemical failure was 79.8% (95% confidence interval [CI], 74.3%-85.0%) and 70.9% (95% CI, 65.4%-76.0%) for the HDRB and EBRT groups, respectively, equating to a hazard ratio of 0.59 (95% CI, 0.43-0.81, P=.0011). Interaction analyses showed no alteration in HDR efficacy when planned androgen deprivation therapy was administered (P=.95), but a strong trend toward reduced efficacy was shown compared to EBRT in high-risk cases (P=.06). Rates of grade 3 urethral stricture were 0.3% (95% CI, 0%-0.9%) and 11.8% (95% CI, 8.1%-16.5%) for EBRT and HDRB, respectively (P<.0001). No differences in clinical outcomes were observed. Conclusions: This comparison of 2 individual contemporaneously treated HDRB and EBRT approaches showed improved freedom from biochemical progression with the HDR approach. The benefit was more pronounced in intermediate- risk patients but needs to be weighed against

  12. Direct 2-Arm Comparison Shows Benefit of High-Dose-Rate Brachytherapy Boost vs External Beam Radiation Therapy Alone for Prostate Cancer

    International Nuclear Information System (INIS)

    Purpose: To evaluate the outcomes of patients treated for intermediate- and high-risk prostate cancer with a single schedule of either external beam radiation therapy (EBRT) and high-dose-rate brachytherapy (HDRB) boost or EBRT alone. Methods and Materials: From 2001-2006, 344 patients received EBRT with HDRB boost for definitive treatment of intermediate- or high-risk prostate cancer. The prescribed EBRT dose was 46 Gy in 23 fractions, with a HDR boost of 19.5 Gy in 3 fractions. This cohort was compared to a contemporaneously treated cohort who received EBRT to 74 Gy in 37 fractions, using a matched pair analysis. Three-dimensional conformal EBRT was used. Matching was performed using a propensity score matching technique. High-risk patients constituted 41% of the matched cohorts. Five-year clinical and biochemical outcomes were analyzed. Results: Initial significant differences in prognostic indicators between the unmatched treatment cohorts were rendered negligible after matching, providing a total of 688 patients. Median biochemical follow-up was 60.5 months. The 5-year freedom from biochemical failure was 79.8% (95% confidence interval [CI], 74.3%-85.0%) and 70.9% (95% CI, 65.4%-76.0%) for the HDRB and EBRT groups, respectively, equating to a hazard ratio of 0.59 (95% CI, 0.43-0.81, P=.0011). Interaction analyses showed no alteration in HDR efficacy when planned androgen deprivation therapy was administered (P=.95), but a strong trend toward reduced efficacy was shown compared to EBRT in high-risk cases (P=.06). Rates of grade 3 urethral stricture were 0.3% (95% CI, 0%-0.9%) and 11.8% (95% CI, 8.1%-16.5%) for EBRT and HDRB, respectively (P<.0001). No differences in clinical outcomes were observed. Conclusions: This comparison of 2 individual contemporaneously treated HDRB and EBRT approaches showed improved freedom from biochemical progression with the HDR approach. The benefit was more pronounced in intermediate- risk patients but needs to be weighed against

  13. A boost for the ISOLDE beams

    CERN Multimedia

    Corinne Pralavorio

    2015-01-01

    The first HIE-ISOLDE cryomodule was commissioned at the end of October. The radioactive ion beams can now be accelerated to 4.3 MeV per nucleon.   The ISOLDE beamline that supplies the Miniball array. The first HIE-ISOLDE cryomodule can be seen in the background, in its light-grey cryostat. ISOLDE is getting an energy boost. The first cryomodule of the new superconducting linear accelerator HIE-ISOLDE (High Intensity and Energy ISOLDE), located downstream of the REX-ISOLDE accelerator, increases the energy of the radioactive ion beams from 3 to 4.3 MeV per nucleon. It supplies the Miniball array, where an experiment using radioactive zinc ions (see box) began at the end of October. This is the first stage in the commissioning of HIE-ISOLDE. The facility will ultimately be equipped with four cryomodules that will accelerate the beams to 10 MeV per nucleon. Each cryomodule has five accelerating cavities and a solenoid, which focuses the beam. All of these components are superconducting. This first ...

  14. Results of high dose rate afterloading brachytherapy boost to conventional external beam radiation therapy for initial and locally advanced prostate cancer

    International Nuclear Information System (INIS)

    Purpose: To evaluate the impact on biochemical control (bNED), acute and late gastro-intestinal (GI) and urological (GU) morbidity of initial and locally advanced prostate cancer treated with fractionated transrectal ultrasound-guided (TRUS) high dose rate after loading brachytherapy (HDR-B) as a boost to conventional external beam radiation therapy (EBRT). Patients and methods: From March 1997 to February 2000 a total of 119 patients with any of the following characteristics were eligible for study entry: biopsy proven adenocarcinoma Gleason scored (GS), initial prostatic specific antigen (PSA) level dosage 1992 AJCC clinical stage T3a or less, and prostatic volume <60 cc. All patients had prior to HDR-B a course of EBRT 6 MV photons to a median dose of 45 Gy, in 1.8 Gy fractions, to the prostate and seminal vesicles only. HDR-B treatment planning and dosimetric calculations were generated with the Nucletron Planning System. Patients were grouped into two groups, according to their risk for biochemical failure: low-risk group without (LR) or with neoadjuvant total androgen deprivation (AD) prior to EBRT (LR+AD) and high-risk group without (HR) or with neoadjuvant AD (HR+AD), for bNED and dose-escalation protocol. LR encompassed patients who presented GS<6, T1 or T2a and or initial PSA<10 ng/ml, who were treated with 16 Gy (4 Gy fractions, b.i.d.) HDR-B. The remaining patients were grouped into HR or HR+AD and received 20 Gy (5 Gy fractions, b.i.d.) HDR-B. The planning was optimized using the standard geometric optimization. Biological effective doses (BED) for tumor control and late responding tissue were calculated using a α/β ratio of 1.5 and 3 Gy, respectively. They were matched with bNED, acute and late gastrointestinal (GI) and urological (GU) morbidity, according to the RTOG/EORTC scoring criteria. Results: Median age of patients was 68 years (range 47-83), with a median follow-up of 41 months (range 18-48). The crude and actuarial biochemical controls (b

  15. Whole brain radiotherapy with a conformational external beam radiation boost for lung cancer patients with 1-3 brain metastasis: a multi institutional study

    International Nuclear Information System (INIS)

    To determine the outcome of patients with brain metastasis (BM) from lung cancer treated with an external beam radiotherapy boost (RTB) after whole brain radiotherapy (WBRT). A total of 53 BM patients with lung cancer were treated sequentially with WBRT and RTB between 1996 and 2008 according to our institutional protocol. Mean age was 58.8 years. The median KPS was 90. Median recursive partitioning analysis (RPA) and graded prognostic assessment (GPA) grouping were 2 and 2.5, respectively. Surgery was performed on 38 (71%) patients. The median number of BM was 1 (range, 1-3). Median WBRT and RTB combined dose was 39 Gy (range, 37.5 - 54). Median follow-up was 12.0 months. During the period of follow-up, 37 (70%) patients died. The median overall survival (OS) was 14.5 months. Only 13 patients failed in the brain. The majority of patients (n = 29) failed distantly. The 1-year OS, -local control, extracranial failure rates were 61.2%, 75.2% and 60.8%, respectively. On univariate analysis, improved OS was found to be significantly associated with total dose (≤ 39 Gy vs. > 39 Gy; p < 0.01), age < 65 (p < 0.01), absence of extracranial metastasis (p < 0.01), GPA ≥ 2.5 (p = 0.01), KPS ≥ 90 (p = 0.01), and RPA < 2 (p = 0.04). On multivariate analysis, total dose (p < 0.01) and the absence of extracranial metastasis (p = 0.03) retained statistical significance. The majority of lung cancer patients treated with WBRT and RTB progressed extracranially. There might be a subgroup of younger patients with good performance status and no extracranial disease who may benefit from dose escalation after WBRT to the metastatic site

  16. Positive Surgical Margins in Soft Tissue Sarcoma Treated With Preoperative Radiation: Is a Postoperative Boost Necessary?

    International Nuclear Information System (INIS)

    Purpose: For patients with an extremity soft tissue sarcoma (STS) treated with preoperative radiotherapy and surgically excised with positive margins, we retrospectively reviewed whether a postoperative radiation boost reduced the risk of local recurrence (LR). Methods and Materials: A total of 216 patients with positive margins after resection of an extremity STS treated between 1986 and 2003 were identified from our institution's prospectively collected database. Patient demographics, radiation therapy parameters including timing and dose, classification of positive margin status, reasons for not administering a postoperative boost, and oncologic outcome were collected and evaluated. Results: Of the 216 patients with a positive surgical margin, 52 patients were treated with preoperative radiation therapy alone (50 Gy), whereas 41 received preoperative radiation therapy plus a postoperative boost (80% received 16 Gy postoperatively for a total of 66 Gy). There was no difference in baseline tumor characteristics between the two groups. Six of 52 patients in the group receiving preoperative radiation alone developed a LR compared with 9 of 41 in the boost group. Five-year estimated LR-free survivals were 90.4% and 73.8%, respectively (p = 0.13). Conclusions: We found that including the postoperative radiation boost after preoperative radiation and a margin-positive excision did not provide an advantage in preventing LR for patients treated with external beam radiotherapy. Given that higher radiation doses placed patients at greater risk for late complications such as fracture, fibrosis, edema, and joint stiffness, judicious avoidance of the postoperative boost while maintaining an equivalent rate of local control can reduce the risk of these difficult-to-treat morbidities.

  17. Cyclotron radiation beam control

    International Nuclear Information System (INIS)

    This patent application describes an apparatus for attenuating a beam of particulate radiation comprising a series of modules, each module being constituted by a sphere having a passage, a cupola covering said sphere and a base supporting said sphere, and means for causing movement of the spheres for aligning said passages with an axis of a beam line and arranging said passages out of alignment so as to attenuate the beam. (author)

  18. Normal tissue dosimetric comparison between hdr prostate implant boost and conformal external beam radiotherapy boost: potential for dose escalation

    International Nuclear Information System (INIS)

    Purpose: To compare the dose and volume of bladder and rectum treated using high-dose-rate (HDR) prostate implant boost versus conformal external beam radiotherapy boost, and to use the dose-volume information to perform a critical volume tolerance (CVT) analysis and then estimate the potential for further dose escalation using HDR brachytherapy boost. Methods and Materials: Using CT scan data collected before and after patients underwent HDR prostate implant, a 7-field conformal prostate-only external beam treatment plan and HDR brachytherapy treatment plan were constructed for each patient. Doses to the normal structures were calculated. Dose-volume histograms (DVH) were plotted for comparison of the two techniques. Wilcoxon signed rank test was performed at four dose levels to compare the dose to normal structures between the two treatment techniques. The acute and late effects of HDR brachytherapy were calculated based on the linear-quadratic (LQ) model. CVT analyses were performed to calculate the potential dose gain (PDG) using HDR brachytherapy boost. Results: The volume of bladder and rectum receiving high dose was significantly less from implant boost. On the average, 0.19 cc of the bladder received 100% of the brachytherapy prescription dose, compared with 5.1 cc of the bladder receiving 100% of the prescription dose in the 7-field conformal external beam radiotherapy boost. Similarly, 0.25 cc of the rectum received 100% of the dose with the implant boost, as compared to 2.9 cc in the conformal external beam treatment. The implant also delivered higher doses inside the prostate volume. On average, 47% of the prostate received ≥150% of the prescription dose. The CVT analysis revealed a range of PDG using the HDR brachytherapy boost which depended on the following variables: critical volume (CV), critical volume tolerance dose (CVTD), number of HDR fractions (N), and the dose of external beam radiotherapy (XRT) delivered with brachytherapy boost. The PDG

  19. Limb-sparing management with surgical resection, external-beam and intraoperative electron-beam radiation therapy boost for patients with primary soft tissue sarcoma of the extremity. A multicentric pooled analysis of long-term outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, Felipe A. [Hospital General Universitario Gregorio Maranon, Department of Oncology, Madrid (Spain); Complutense University, School of Medicine, Madrid (Spain); Sole, Claudio V. [Hospital General Universitario Gregorio Maranon, Department of Oncology, Madrid (Spain); Complutense University, School of Medicine, Madrid (Spain); Instituto de Radiomedicina, Service of Radiation Oncology, Santiago (Chile); Polo, Alfredo; Montero, Angel [Hospital Universitario Ramon y Cajal, Service of Radiation Oncology, Madrid (Spain); Cambeiro, Mauricio; Martinez-Monge, Rafael [Clinica Universidad de Navarra, Service of Radiation Oncology, Pamplona (Spain); Alvarez, Ana [Hospital General Universitario Gregorio Maranon, Service of Radiation Oncology, Madrid (Spain); Cuervo, Miguel [Hospital General Universitario Gregorio Maranon, Service of Orthopedics and Traumatology, Madrid (Spain); Julian, Mikel San [Clinica Universidad de Navarra, Service of Orthopedics and Traumatology, Pamplona (Spain)

    2014-10-15

    A joint analysis of data from three contributing centres within the intraoperative electron-beam radiation therapy (IOERT) Spanish program was performed to investigate the main contributions of IORT to the multidisciplinary treatment of high-risk extremity soft tissue sarcoma (STS). Patients with an histologic diagnosis of primary extremity STS, with absence of distant metastases, undergoing limb-sparing surgery with radical intent, external beam radiotherapy (median dose 45 Gy) and IOERT (median dose 12.5 Gy) were considered eligible for participation in this study. From 1986-2012, a total of 159 patients were analysed in the study from three Spanish institutions. With a median follow-up time of 53 months (range 4-316 years), 5-year local control (LC) was 82 %. The 5-year IOERT in-field control, disease-free survival (DFS) and overall survival (OS) were 86, 62 and 72 %, respectively. On multivariate analysis, only microscopically involved margin (R1) resection status retained significance in relation to LC (HR 5.20, p < 0.001). With regard to IOERT in-field control, incomplete resection (HR 4.88, p = 0.001) and higher IOERT dose (≥ 12.5 Gy; HR 0.32, p = 0.02) retained a significant association in multivariate analysis. From this joint analysis emerges the fact that an IOERT dose ≥ 12.5 Gy increases the rate of IOERT in-field control, but DFS remains modest, given the high risk of distant metastases. Intensified local treatment needs to be tested in the context of more efficient concurrent, neo- and adjuvant systemic therapy. (orig.) [German] Um den therapeutischen Beitrag einer intraoperativen Bestrahlung mit Elektronen (IOERT) als Teil eines multidisziplinaeren Behandlungskonzepts von Weichteilsarkomen (STS) im Extremitaetenbereich mit hohem Risikoprofil evaluieren zu koennen, wurde anhand des spanischen IOERT-Programms eine gepoolte Datenanalyse von drei teilnehmenden Zentren vorgenommen. Eingeschlossen in diese Studie wurden Patienten mit histologisch

  20. Impact of the Radiation Boost on Outcomes After Breast-Conserving Surgery and Radiation

    International Nuclear Information System (INIS)

    Purpose: We examined the impact of radiation tumor bed boost parameters in early-stage breast cancer on local control and cosmetic outcomes. Methods and Materials: A total of 3,186 women underwent postlumpectomy whole-breast radiation with a tumor bed boost for Tis to T2 breast cancer from 1970 to 2008. Boost parameters analyzed included size, energy, dose, and technique. Endpoints were local control, cosmesis, and fibrosis. The Kaplan-Meier method was used to estimate actuarial incidence, and a Cox proportional hazard model was used to determine independent predictors of outcomes on multivariate analysis (MVA). The median follow-up was 78 months (range, 1-305 months). Results: The crude cosmetic results were excellent in 54%, good in 41%, and fair/poor in 5% of patients. The 10-year estimate of an excellent cosmesis was 66%. On MVA, independent predictors for excellent cosmesis were use of electron boost, lower electron energy, adjuvant systemic therapy, and whole-breast IMRT. Fibrosis was reported in 8.4% of patients. The actuarial incidence of fibrosis was 11% at 5 years and 17% at 10 years. On MVA, independent predictors of fibrosis were larger cup size and higher boost energy. The 10-year actuarial local failure was 6.3%. There was no significant difference in local control by boost method, cut-out size, dose, or energy. Conclusions: Likelihood of excellent cosmesis or fibrosis are associated with boost technique, electron energy, and cup size. However, because of high local control and rare incidence of fair/poor cosmesis with a boost, the anatomy of the patient and tumor cavity should ultimately determine the necessary boost parameters.

  1. A simple method for boosting the beam quality of commercial DPL

    Institute of Scientific and Technical Information of China (English)

    张光寅; 焦志勇; 颜彩繁; 丁欣; 张潮波; 张晓华; 顾学文; 宋峰

    2003-01-01

    A simple method for boosting the beam quality of a commercial laser diode pumped laser (DPL) is put forward.By keeping one of the mirrors unchanged and the moving the other mirror a proper distance away from the laser rod,high beam quality laser output is realized.

  2. FULL ELECTROMAGNETIC SIMULATION OF COHERENT SYNCHROTRON RADIATION VIA THE LORENTZ-BOOSTED FRAME APPROACH

    International Nuclear Information System (INIS)

    Numerical simulation of some systems containing charged particles with highly relativistic directed motion can by speeded up by orders of magnitude by choice of the proper Lorentz-boosted frame. Orders of magnitude speedup has been demonstrated for simulations from first principles of laser-plasma accelerator, free electron laser, and particle beams interacting with electron clouds. Here we address the application of the Lorentz-boosted frame approach to coherent synchrotron radiation (CSR), which can be strongly present in bunch compressor chicanes. CSR is particularly relevant to the next generation of x-ray light sources and is simultaneously difficult to simulate in the lab frame because of the large ratio of scale lengths. It can increase both the incoherent and coherent longitudinal energy spread, effects that often lead to an increase in transverse emittance. We have adapted the WARP code to simulate CSR emission along a simple dipole bend. We present some scaling arguments for the possible computational speed up factor in the boosted frame and initial 3D simulation results.

  3. Impact of intensity-modulated radiation therapy as a boost treatment on the lung-dose distributions for non-small-cell lung cancer

    International Nuclear Information System (INIS)

    Purpose: To investigate the feasibility of intensity-modulated radiotherapy (IMRT) as a method of boost radiotherapy after the initial irradiation by the conventional anterior/posterior opposed beams for centrally located non-small-cell lung cancer through the evaluation of dose distributions according to the various boost methods. Methods and Materials: Seven patients with T3 or T4 lung cancer and mediastinal node enlargement who previously received radiotherapy were studied. All patients underwent virtual simulation retrospectively with the previous treatment planning computed tomograms. Initial radiotherapy plans were designed to deliver 40 Gy to the primary tumor and involved nodal regions with the conventional anterior/posterior opposed beams. Two radiation dose levels, 24 and 30 Gy, were used for the boost radiotherapy plans, and four different boost methods (a three-dimensional conformal radiotherapy [3DCRT], five-, seven-, and nine-beam IMRT) were applied to each dose level. The goals of the boost plans were to deliver the prescribed radiation dose to 95% of the planning target volume (PTV) and minimize the volumes of the normal lungs and spinal cord irradiated above their tolerance doses. Dose distributions in the PTVs and lungs, according to the four types of boost plans, were compared in the boost and sum plans, respectively. Results: The percentage of lung volumes irradiated >20 Gy (V20) was reduced significantly in the IMRT boost plans compared with the 3DCRT boost plans at the 24- and 30-Gy dose levels (p 0.007 and 0.0315 respectively). Mean lung doses according to the boost methods were not different in the 24- and 30-Gy boost plans. The conformity indexes (CI) of the IMRT boost plans were lower than those of the 3DCRT plans in the 24- and 30-Gy plans (p = 0.001 in both). For the sum plans, there was no difference of the dose distributions in the PTVs and lungs according to the boost methods. Conclusions: In the boost plans the V20s and CIs were

  4. Beam diagnostics with synchrotron radiation

    International Nuclear Information System (INIS)

    Synchrotron radiation is often used to measure the dimensions of an electron beam. The transverse size is obtained from an image of the beam cross section formed by means of the emitted synchrotron radiation. Because of the small natural opening angle the resolution is limited by diffraction. The angular spread of the particles in the beam can be measured by observing the radiation directly. Here, the resolution is limited by the natural opening angle of the emitted light. Measuring both beam cross section and angular spread gives the emittance of the beam. However, in most cases only one of these two parameters is observed and the other deduced from the known particle beam optics at the source of the radiation. Usually one observes radiation emitted in long bending magnets. However, short magnets and undulators are also useful sources for these measurements. For practical reasons the beam diagnostics is carried out using visible or ultraviolet light. This part of the spectrum is usually far below the critical frequency, and corresponding approximations can be applied. Synchrotron radiation is an extremely useful tool for diagnostics in electron (or positron) rings. In some cases it has also served in proton rings using special magnets. (author)

  5. Breast boost - why, how, when...?

    International Nuclear Information System (INIS)

    Background: Breast conservation management including tumorectomy or quadrantectomy and external beam radiotherapy with a dose of 45 to 50 Gy in the treatment of small breast carcinomas is generally accepted. The use of a radiation boost - in particular for specific subgroups - has not been clarified. With regard to the boost technique there is some controversy between groups emphasizing the value of electron boost treatment and groups pointing out the value of interstitial boost treatment. This controversy has become even more complicated as there is an increasing number of institutions reporting the use of HDR interstitial brachytherapy for boost treatment. The most critical issue with regard to interstitial HDR brachytherapy is the assumed serious long-term morbidity after a high single radiation dose as used in HDR-treatments. Methods and Results: This article gives a perspective and recommendations on some aspects of this issue (indication, timing, target volume, dose and dose rate). Conclusion: More information about the indication for a boost is to be expected from the EORTC trial 22881/10882. Careful selection of treatment procedures for specific subgroups of patients and refinement in surgical procedures and radiotherapy techniques may be useful in improving the clinical and cosmetic results in breast conservation therapy. Prospective trials comparing on the one hand different boost techniques and on the other hand particular morphologic criteria in treatments with boost and without boost are needed to give more detailed recommendations for boost indication and for boost techniques. (orig.)

  6. Benefit of Radiation Boost After Whole-Breast Radiotherapy

    International Nuclear Information System (INIS)

    Purpose: To determine whether a boost to the tumor bed after breast-conserving surgery (BCS) and radiotherapy (RT) to the whole breast affects local control and disease-free survival. Methods and Materials: A total of 1,138 patients with pT1 to pT2 breast cancer underwent adjuvant RT at the University of Florence. We analyzed only patients with a minimum follow-up of 1 year (range, 1-20 years), with negative surgical margins. The median age of the patient population was 52.0 years (±7.9 years). The breast cancer relapse incidence probability was estimated by the Kaplan-Meier method, and differences between patient subgroups were compared by the log rank test. Cox regression models were used to evaluate the risk of breast cancer relapse. Results: On univariate survival analysis, boost to the tumor bed reduced breast cancer recurrence (p < 0.0001). Age and tamoxifen also significantly reduced breast cancer relapse (p = 0.01 and p = 0.014, respectively). On multivariate analysis, the boost and the medium age (45-60 years) were found to be inversely related to breast cancer relapse (hazard ratio [HR], 0.27; 95% confidence interval [95% CI], 0.14-0.52, and HR 0.61; 95% CI, 0.37-0.99, respectively). The effect of the boost was more evident in younger patients (HR, 0.15 and 95% CI, 0.03-0.66 for patients <45 years of age; and HR, 0.31 and 95% CI, 0.13-0.71 for patients 45-60 years) on multivariate analyses stratified by age, although it was not a significant predictor in women older than 60 years. Conclusion: Our results suggest that boost to the tumor bed reduces breast cancer relapse and is more effective in younger patients.

  7. Four-Week Course of Radiation for Breast Cancer Using Hypofractionated Intensity Modulated Radiation Therapy With an Incorporated Boost

    International Nuclear Information System (INIS)

    Purpose: Standard radiation for early breast cancer requires daily treatment for 6 to 7 weeks. This is an inconvenience to many women, and for some a barrier for breast conservation. We present the acute toxicity of a 4-week course of hypofractionated radiation. Methods and Materials: A total of 75 patients completed radiation on a Phase II trial approved by the hospital institutional review board. Eligibility criteria were broad to include any patient normally eligible for standard radiation: age ≥18 years, invasive or in situ cancer, American Joint Committee on Cancer Stage 0 to II, breast-conserving surgery, and any systemic therapy not given concurrently. The median age was 52 years (range, 31-81 years). Of the patients, 15% had ductal carcinoma in situ, 67% T1, and 19% T2; 71% were N0, 17% N1, and 12% NX. Chemotherapy was given before radiation in 44%. Using photon intensity-modulated radiation therapy and incorporated electron beam boost, the whole breast received 45 Gy and the lumpectomy bed 56 Gy in 20 treatments over 4 weeks. Results: The maximum acute skin toxicity by the end of treatment was Grade 0 in 9 patients (12%), Grade 1 in 49 (65%) and Grade 2 in 17 (23%). There was no Grade 3 or higher skin toxicity. After radiation, all Grade 2 toxicity had resolved by 6 weeks. Hematologic toxicity was Grade 0 in most patients except for Grade 1 neutropenia in 2 patients, and Grade 1 anemia in 11 patients. There were no significant differences in baseline vs. 6-week posttreatment patient-reported or physician-reported cosmetic scores. Conclusions: This 4-week course of postoperative radiation using intensity-modulated radiation therapy is feasible and is associated with acceptable acute skin toxicity and quality of life. Long-term follow-up data are needed. This radiation schedule may represent an alternative both to longer 6-week to 7-week standard whole-breast radiation and more radically shortened 1-week, partial-breast treatment schedules

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

    OpenAIRE

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

    2013-01-01

    Introduction 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. Methods CT data set...

  9. Impact of Boost Radiation in the Treatment of Ductal Carcinoma In Situ: A Population-Based Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Rakovitch, Eileen, E-mail: Eileen.rakovitch@sunnybrook.ca [Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Toronto, Ontario (Canada); Institute for Clinical Evaluative Sciences, Toronto, Ontario (Canada); University of Toronto, Toronto, Ontario (Canada); Narod, Steven A. [University of Toronto, Toronto, Ontario (Canada); Women’s College Research Institute, Toronto, Ontario (Canada); Nofech-Moses, Sharon; Hanna, Wedad [Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Toronto, Ontario (Canada); University of Toronto, Toronto, Ontario (Canada); Thiruchelvam, Deva; Saskin, Refik; Taylor, Carole [Institute for Clinical Evaluative Sciences, Toronto, Ontario (Canada); Tuck, Alan [London Health Sciences Center, London, Ontario (Canada); Youngson, Bruce; Miller, Naomi; Done, Susan J. [University Health Network, Toronto, Ontario (Canada); Sengupta, Sandip [Kingston General Hospital, Kingston, Ontario (Canada); Elavathil, Leela [University of Toronto, Toronto, Ontario (Canada); Henderson General Hospital, 711 Concession Street, Hamilton, Ontario (Canada); Jani, Prashant A. [University of Toronto, Toronto, Ontario (Canada); Regional Health Sciences Centre, Thunder Bay, Ontario (Canada); Bonin, Michel [Sudbury Regional Hospital, Sudbury, Ontario (Canada); Metcalfe, Stephanie [Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Toronto, Ontario (Canada); Paszat, Lawrence [Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Toronto, Ontario (Canada); Institute for Clinical Evaluative Sciences, Toronto, Ontario (Canada); University of Toronto, Toronto, Ontario (Canada)

    2013-07-01

    Purpose: To report the outcomes of a population of women with ductal carcinoma in situ (DCIS) treated with breast-conserving surgery and radiation and to evaluate the independent effect of boost radiation on the development of local recurrence. Methods and Materials: All women diagnosed with DCIS and treated with breast-conserving surgery and radiation therapy in Ontario from 1994 to 2003 were identified. Treatments and outcomes were identified through administrative databases and validated by chart review. The impact of boost radiation on the development of local recurrence was determined using survival analyses. Results: We identified 1895 cases of DCIS that were treated by breast-conserving surgery and radiation therapy; 561 patients received boost radiation. The cumulative 10-year rate of local recurrence was 13% for women who received boost radiation and 12% for those who did not (P=.3). The 10-year local recurrence-free survival (LRFS) rate among women who did and who did not receive boost radiation was 88% and 87%, respectively (P=.27), 94% and 93% for invasive LRFS (P=.58), and was 95% and 93% for DCIS LRFS (P=.31). On multivariable analyses, boost radiation was not associated with a lower risk of local recurrence (hazard ratio = 0.82, 95% confidence interval 0.59-1.15) (P=.25). Conclusions: Among a population of women treated with breast-conserving surgery and radiation for DCIS, additional (boost) radiation was not associated with a lower risk of local or invasive recurrence.

  10. Emittance in particle and radiation beam techniques

    International Nuclear Information System (INIS)

    The author discusses the important and diverse role of the phase space area - the emittance - in the advanced techniques involving interaction of particle and radiation beams. For undulator radiation from unbunched beams, the radiation phase space is diluted from the coherent phase space of the single electron radiation. When the undulator radiation is used as a light source, it is important to minimize the dilution by decreasing the beam emittance and matching the phase space distributions of the particle and the radiation beams. For optical stochastic cooling, on the other hand, the phase space should be maximally mismatched for efficient cooling. In the case particles are bunched to a length much shorter than the radiation wavelength, the emittance appears as an intensity enhancement factor. In the operation of free electron lasers, the phase space matching becomes doubly important, once as the dilution factor in the initial stage of energy modulation and then as the radiation efficiency factor at the end where the beam is density modulated. The author then discusses some of the beam cooling techniques producing smaller emittances, especially the recent suggestions for relativistic heavy ions in storage rings or electron beams in linacs. These are based on the radiative cooling that occurs when particle beams backscatter powerful laser beams

  11. Dosimetric evaluation of simultaneous integrated boost during stereotactic body radiation therapy for pancreatic cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wensha, E-mail: wensha.yang@cshs.org [Department of Radiation Oncology, Cedars Sinai Medical Center, Los Angeles, CA (United States); Reznik, Robert; Fraass, Benedick A. [Department of Radiation Oncology, Cedars Sinai Medical Center, Los Angeles, CA (United States); Nissen, Nicholas [Department of Surgery, Cedars Sinai Medical Center, Los Angeles, CA (United States); Hendifar, Andrew [Department of Gastrointestinal Oncology, Cedars Sinai Medical Center, Los Angeles, CA (United States); Wachsman, Ashley [Department of Cross-Sectional Imaging Interventional Oncology, Cedars Sinai Medical Center, Los Angeles, CA (United States); Sandler, Howard; Tuli, Richard [Department of Radiation Oncology, Cedars Sinai Medical Center, Los Angeles, CA (United States)

    2015-04-01

    Stereotactic body radiation therapy (SBRT) provides a promising way to treat locally advanced pancreatic cancer and borderline resectable pancreatic cancer. A simultaneous integrated boost (SIB) to the region of vessel abutment or encasement during SBRT has the potential to downstage otherwise likely positive surgical margins. Despite the potential benefit of using SIB-SBRT, the ability to boost is limited by the local geometry of the organs at risk (OARs), such as stomach, duodenum, and bowel (SDB), relative to tumor. In this study, we have retrospectively replanned 20 patients with 25 Gy prescribed to the planning target volume (PTV) and 33~80 Gy to the boost target volume (BTV) using an SIB technique for all patients. The number of plans and patients able to satisfy a set of clinically established constraints is analyzed. The ability to boost vessels (within the gross target volume [GTV]) is shown to correlate with the overlap volume (OLV), defined to be the overlap between the GTV + a 1(OLV1)- or 2(OLV2)-cm margin with the union of SDB. Integral dose, boost dose contrast (BDC), biologically effective BDC, tumor control probability for BTV, and normal tissue complication probabilities are used to analyze the dosimetric results. More than 65% of the cases can deliver a boost to 40 Gy while satisfying all OAR constraints. An OLV2 of 100 cm{sup 3} is identified as the cutoff volume: for cases with OLV2 larger than 100 cm{sup 3}, it is very unlikely the case could achieve 25 Gy to the PTV while successfully meeting all the OAR constraints.

  12. Dose escalation with stereotactic body radiation therapy boost for locally advanced non small cell lung cancer

    International Nuclear Information System (INIS)

    Low survival outcomes have been reported for the treatment of locally advanced non small cell lung cancer (LA-NSCLC) with the standard of care treatment of concurrent chemoradiation (cCRT). We present our experience of dose escalation using stereotactic body radiosurgery (SBRT) following conventional cCRT for patients with LA-NSCLC. Sixteen patients with a median age of 67.5 treated with fractionated SBRT from 2010 to 2012 were retrospectively analyzed. Nine (56%) of the patients had stage IIIB, 6 (38%) has stage IIIA, and 1 (6%) had recurrent disease. Majority of the patients (63%) presented with N2 disease. All patients had a PET CT for treatment planning. Patients received conventional cCRT to a median dose of 50.40 Gy (range 45–60) followed by an SBRT boost with an average dose of 25 Gy (range 20–30) given over 5 fractions. With a median follow-up of 14 months (range, 1–14 months), 1-year overall survival (OS), progression free survival (PFS), local control (LC), regional control (RC), and distant control (DC) rates were, 78%, 42%, 76%, 79%, and 71%, respectively. Median times to disease progression and regional failure were 10 months and 18 months, respectively. On univariate analysis, advanced age and nodal status were worse prognostic factors of PFS (p < 0.05). Four patients developed radiation pneumonitis and one developed hemoptysis. Treatment was interrupted in one patient who required hospitalization due to arrhythmias and pneumonia. Risk adaptive dose escalation with SBRT following external beam radiotherapy is possible and generally tolerated treatment option for patients with LA-NSCLC

  13. Radiation therapy apparatus having retractable beam stopper

    International Nuclear Information System (INIS)

    This invention relates to a radiation therapy apparatus which utilized a linear translation mechanism for positioning a beam stopper. An apparatus is described wherein the beam stopper is pivotally attached to the therapy machine with an associated drive motor in such a way that the beam stopper retracts linearly

  14. PSA kinetics after external beam radiotherapy alone or combined with an iridium brachytherapy boost to deliver 85 grays to prostatic adenocarcinoma

    International Nuclear Information System (INIS)

    Purpose: Increasing the dose to prostatic adenocarcinoma in conformal external beam therapy (EBT) has resulted in increased levels of PSA normalization and increased percentage of biochemical disease-free survival rates. However technical problems due to prostate motion inside the pelvis or patients's set-up make difficult the realization of the EBT boost fields above 72 Gy. Brachytherapy which overcomes these problems was investigated to deliver the boost dose to achieve 85 Gy. PSA nadir which has been identified as the strongest independent predictor of any failure in many studies has been used as the end point for early evaluation of this work. Patients and Methods: In a retrospective way we report on 163 patients' PSA kinetics after EBT alone to 68 Gy or EBT first and a brachytherapy boost up to 75 or 85 Gy. Results: At 12 months follow-up, PSA nadirs percentage ≤0.5 or ≤1 ng/ml increased from 7.5 and 20.7% after 68 Gy EBT to 49.8 and 71.2% after a brachytherapy boost to deliver 85 Gy (p<0.0001). In the Cox PH model analysis, the total dose remained the most important factor for predicting PSA normalization. Conclusions: These results are in accordance with the most recent results published after conformal EBT at the same 80 Gy level of dose. If confirmed on a higher number of patients they could place brachytherapy among the most accurate methods of boosting in the radiation treatment of prostatic carcinoma. (orig.)

  15. Disease Control and Ototoxicity Using Intensity-Modulated Radiation Therapy Tumor-Bed Boost for Medulloblastoma

    International Nuclear Information System (INIS)

    Purpose: We previously reported excellent local control for treating medulloblastoma with a limited boost to the tumor bed. In order to decrease ototoxicity, we subsequently implemented a tumor-bed boost using intensity-modulated radiation therapy (IMRT), the clinical results of which we report here. Patients and Methods: A total of 33 patients with newly diagnosed medulloblastoma, 25 with standard risk, and 8 with high risk, were treated on an IMRT tumor-bed boost following craniospinal irradiation (CSI). Six standard-risk patients were treated with an institutional protocol with 18 Gy CSI in conjunction with intrathecal iodine-131-labeled monoclonal antibody. The majority of patients received concurrent vincristine and standard adjuvant chemotherapy. Pure-tone audiograms were graded according to National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0. Results: Median age was 9 years old (range, 4-46 years old). Median follow-up was 63 months. Kaplan-Meier estimates of progression-free survival (PFS) and overall survival (OS) rates for standard-risk patients who received 23.4 or 36 Gy CSI (not including those who received 18 Gy CSI with radioimmunotherapy) were 81.4% and 88.4%, respectively, at 5 years; 5-year PFS and OS rates for high-risk patients were both 87.5%. There were no isolated posterior fossa failures outside of the boost volume. Posttreatment audiograms were available for 31 patients, of whom 6%, at a median follow-up of 19 months, had developed Grade 3 hearing loss. Conclusion: An IMRT tumor-bed boost results in excellent local control while delivering a low mean dose to the cochlea, resulting in a low rate of ototoxicity.

  16. Radiation dermatitis following electron beam therapy

    International Nuclear Information System (INIS)

    Ten patients, who had been treated for mycosis fungoides with electron beam radiation ten or more years previously, were examined for signs of radiation dermatitis. Although most patients had had acute radiation dermatitis, only a few manifested signs of mild chronic changes after having received between 1,000 and 2,800 rads

  17. Electron beams in radiation therapy

    International Nuclear Information System (INIS)

    Clinical electron beams in interaction with beam flattening and collimating devices are studied, in order to obtain the means for adequate electron therapy. A treatment planning method for arbitrary field shapes is developed that takes the properties of the collimated electron beams into account. An electron multiple-scattering model is extended to incorporate a model for the loss of electrons with depth, in order to improve electron beam dose planning. A study of ionisation measurements in two different phantom materials yields correction factors for electron beam dosimetry. (Auth.)

  18. SU-F-BRF-07: Impact of Different Patient Setup Strategies in Adaptive Radiation Therapy with Simultaneous Integrated Volume-Adapted Boost of NSCLC

    International Nuclear Information System (INIS)

    Purpose: To evaluate the potential impact of several setup error correction strategies on a proposed image-guided adaptive radiotherapy strategy for locally advanced lung cancer. Methods: Daily 4D cone-beam CT and weekly 4D fan-beam CT images were acquired from 9 lung cancer patients undergoing concurrent chemoradiation therapy. Initial planning CT was deformably registered to daily CBCT images to generate synthetic treatment courses. An adaptive radiation therapy course was simulated using the weekly CT images with replanning twice and a hypofractionated, simultaneous integrated boost to a total dose of 66 Gy to the original PTV and either a 66 Gy (no boost) or 82 Gy (boost) dose to the boost PTV (ITV + 3mm) in 33 fractions with IMRT or VMAT. Lymph nodes (LN) were not boosted (prescribed to 66 Gy in both plans). Synthetic images were rigidly, bony (BN) or tumor and carina (TC), registered to the corresponding plan CT, dose was computed on these from adaptive replans (PLAN) and deformably accumulated back to the original planning CT. Cumulative D98% of CTV of PT (ITV for 82Gy) and LN, and normal tissue dose changes were analyzed. Results: Two patients were removed from the study due to large registration errors. For the remaining 7 patients, D98% for CTV-PT (ITV-PT for 82 Gy) and CTV-LN was within 1 Gy of PLAN for both 66 Gy and 82 Gy plans with both setup techniques. Overall, TC based setup provided better results, especially for LN coverage (p = 0.1 for 66Gy plan and p = 0.2 for 82 Gy plan, comparison of BN and TC), though not significant. Normal tissue dose constraints violated for some patients if constraint was barely achieved in PLAN. Conclusion: The hypofractionated adaptive strategy appears to be deliverable with soft tissue alignment for the evaluated margins and planning parameters. Research was supported by NIH P01CA116602

  19. SU-F-BRF-07: Impact of Different Patient Setup Strategies in Adaptive Radiation Therapy with Simultaneous Integrated Volume-Adapted Boost of NSCLC

    Energy Technology Data Exchange (ETDEWEB)

    Balik, S [Cleveland Clinic Foundation, Cleveland, OH (United States); Weiss, E; Sleeman, W; Wu, Y; Hugo, G [Virginia Commonwealth University, Richmond, VA (United States); Dogan, N [University of Miami, Miami, FL (United States); Fatyga, M [Mayo Clinic, AZ, Phoenix, AZ (United States)

    2014-06-15

    Purpose: To evaluate the potential impact of several setup error correction strategies on a proposed image-guided adaptive radiotherapy strategy for locally advanced lung cancer. Methods: Daily 4D cone-beam CT and weekly 4D fan-beam CT images were acquired from 9 lung cancer patients undergoing concurrent chemoradiation therapy. Initial planning CT was deformably registered to daily CBCT images to generate synthetic treatment courses. An adaptive radiation therapy course was simulated using the weekly CT images with replanning twice and a hypofractionated, simultaneous integrated boost to a total dose of 66 Gy to the original PTV and either a 66 Gy (no boost) or 82 Gy (boost) dose to the boost PTV (ITV + 3mm) in 33 fractions with IMRT or VMAT. Lymph nodes (LN) were not boosted (prescribed to 66 Gy in both plans). Synthetic images were rigidly, bony (BN) or tumor and carina (TC), registered to the corresponding plan CT, dose was computed on these from adaptive replans (PLAN) and deformably accumulated back to the original planning CT. Cumulative D98% of CTV of PT (ITV for 82Gy) and LN, and normal tissue dose changes were analyzed. Results: Two patients were removed from the study due to large registration errors. For the remaining 7 patients, D98% for CTV-PT (ITV-PT for 82 Gy) and CTV-LN was within 1 Gy of PLAN for both 66 Gy and 82 Gy plans with both setup techniques. Overall, TC based setup provided better results, especially for LN coverage (p = 0.1 for 66Gy plan and p = 0.2 for 82 Gy plan, comparison of BN and TC), though not significant. Normal tissue dose constraints violated for some patients if constraint was barely achieved in PLAN. Conclusion: The hypofractionated adaptive strategy appears to be deliverable with soft tissue alignment for the evaluated margins and planning parameters. Research was supported by NIH P01CA116602.

  20. Electron beam instrumentation techniques using coherent radiation

    International Nuclear Information System (INIS)

    Much progress has been made on coherent radiation research since coherent synchrotron radiation was first observed in 1989. The use of coherent radiation as a bunch length diagnostic tool has been studied by several groups. In this paper, brief introductions to coherent radiation and far-infrared measurement are given, the progress and status of their beam diagnostic application are reviewed, different techniques are described, and their advantages and limitations are discussed

  1. ALICE Transition Radiation Detector (TRD), test beam.

    CERN Multimedia

    2003-01-01

    Electrons and positrons can be discriminated from other charged particles using the emission of transition radiation - X-rays emitted when the particles cross many layers of thin materials. To develop such a Transition Radiation Detector(TRD) for ALICE many detector prototypes were tested in mixed beams of pions and electrons, as in the example shown here.

  2. Coherent radiation by short bunch electron beam

    International Nuclear Information System (INIS)

    The electron beam which is accelerated with a linear accelerator forms the bunch of which the length in advancing direction is several millimeter. The radiation in far infrared region and transition radiation emitted from it are the coherent radiation, in which the phase of the radiation components from many electrons are uniform. Consequently, the intensity increases remarkably. By using this, the research on the properties of transition radiation of long wavelength and Cherenkov radiation which were unknown so far because those are weak was carried out. The radiation like this is not only powerful light source, but also it can be utilized to measure the shape of the bunch of accelerated particles. The coherent effect and the intensity of coherent radiation are explained. The spectra and the intensity distribution, the interference of coherent light, the properties of transition radiation, the formation layer of Cherenkov radiation from finite tracks and so on are reported. The measurement of the shape of bunch was carried out, and line-shaped beam and laterally extended beam are explained. The application as light source is reported. (K.I.)

  3. PSA kinetics after external beam radiotherapy alone or combined with an iridium brachytherapy boost to deliver 85 grays to prostatic adenocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Nickers, P. [University Hospital, Liege (Belgium). Radiation Oncology Dept.; Jolimont Hospital, La Louviere (Belgium). Oncology Dept.; Coppens, L.; Leval, J. de [University Hospital, Liege (Belgium). Urology Dept.; Beauduin, M. [Jolimont Hospital, La Louviere (Belgium). Oncology Dept.; Sabatier, J.; Deneufbourg, J.M. [University Hospital, Liege (Belgium). Radiation Oncology Dept.; Albert, A. [University Hospital, Liege (Belgium). Dept. of Statistics

    2001-02-01

    Purpose: Increasing the dose to prostatic adenocarcinoma in conformal external beam therapy (EBT) has resulted in increased levels of PSA normalization and increased percentage of biochemical disease-free survival rates. However technical problems due to prostate motion inside the pelvis or patients's set-up make difficult the realization of the EBT boost fields above 72 Gy. Brachytherapy which overcomes these problems was investigated to deliver the boost dose to achieve 85 Gy. PSA nadir which has been identified as the strongest independent predictor of any failure in many studies has been used as the end point for early evaluation of this work. Patients and Methods: In a retrospective way we report on 163 patients' PSA kinetics after EBT alone to 68 Gy or EBT first and a brachytherapy boost up to 75 or 85 Gy. Results: At 12 months follow-up, PSA nadirs percentage {<=}0.5 or {<=}1 ng/ml increased from 7.5 and 20.7% after 68 Gy EBT to 49.8 and 71.2% after a brachytherapy boost to deliver 85 Gy (p<0.0001). In the Cox PH model analysis, the total dose remained the most important factor for predicting PSA normalization. Conclusions: These results are in accordance with the most recent results published after conformal EBT at the same 80 Gy level of dose. If confirmed on a higher number of patients they could place brachytherapy among the most accurate methods of boosting in the radiation treatment of prostatic carcinoma. (orig.) [German] Hintergrund: Bei der perkutanen Konformationsbestrahlung des Adenokarzinoms der Prostata hat eine Erhoehung der Dosis zu einer erhoehten PSA-Normalisierung und einer erhoehten Rate biochemischer Krankheitsfreiheit gefuehrt. Technische Probleme aufgrund der Beweglichkeit der Prostata innerhalb des Beckens oder der Patientenlagerung lassen eine Eskalation der perkutanen Bestrahlungsdosis ueber 72 Gy jedoch kritisch erscheinen. Daher wurde ein Brachytherapie-Boost bis zu einer Gesamtdosis von 85 Gy untersucht. Als Endpunkt

  4. Conformal Brachytherapy Boost To External Beam Irradiation For Clinically Localized High Risk Prostate Cancer

    International Nuclear Information System (INIS)

    Purpose: To evaluate the efficacy of using a Pd-103 implant as a boost in conjunction with external beam radiotherapy (EBRT) in patients having prostate cancer associated with adverse features. Materials and Methods: 114 consecutive high risk patients have been treated with combination EBRT and Pd-103 implant. 70 patients with follow-up range of 12-42 months (median 24 months) form the basis of this report. Each patient had at least one of the following risk factors for extra-capsular disease extension: Stage T2b or greater ((66(70))), Gleason score ≥ 7 ((38(70))), significantly elevated PSA (typically > 15 ng/ml)((30(70))) or elevated serum prostatic acid phosphatase (SPAP)((17(70))). Patients received median 4140 cGy EBRT to a limited pelvic field followed by a Pd-103 boost (median prescription dose: 8000 cGy). All patients have been followed in a prospective fashion with respect to PSA response, clinical evidence of disease progression and complications. Criteria for biochemical failure was relatively strict, and was analyzed using both, PSA > 2.0 and PSA > 1.0 as end points. Patients whose PSA was still decreasing at last follow-up were censored at that time. Freedom from failure rates were calculated by the method of Kaplan and Meier. Differences between groups were determined by the Log-rank method. Sexual potency was defined as the ability to attain and maintain an erection sufficient for intercourse. Results: Actuarial freedom from biochemical failure at 3 years after treatment was 90% and 78%, when PSA > 2 and PSA > 1 were used, respectively. There are no documented local relapses. 4 patients failed distantly, and all other failures are based solely on rising PSA values. Biochemical failure was higher in patients having Gleason score ≥ 7 (p=0.001), those with PSA >20 (p=0.014) and in those with elevated SPAP (p=0.007). The primary treatment related morbity was temporary, Grade 1-2 urinary symptoms. No patient developed rectal ulceration or prostatic

  5. Radiative trapping in intense laser beams

    Science.gov (United States)

    Kirk, J. G.

    2016-08-01

    The dynamics of electrons in counter-propagating, circularly polarized laser beams are shown to exhibit attractors whose ability to trap particles depends on the ratio of the beam intensities and a single parameter describing radiation reaction. Analytical expressions are found for the underlying limit cycles and the parameter range in which they are stable. In high-intensity optical pulses, where radiation reaction strongly modifies the trajectories, the production of collimated gamma-rays and the initiation of non-linear cascades of electron–positron pairs can be optimized by a suitable choice of the intensity ratio.

  6. Radiative trapping in intense laser beams

    CERN Document Server

    Kirk, J G

    2016-01-01

    The dynamics of electrons in counter-propagating, circularly polarized laser beams are shown to exhibit attractors whose ability to trap particles depends on the ratio of the beam intensities and a single parameter describing radiation reaction. Analytical expressions are found for the underlying limit cycles and the parameter range in which they are stable. In high-intensity optical pulses, where radiation reaction strongly modifies the trajectories, the production of collimated gamma-rays and the initiation of non-linear cascades of electron-positron pairs can be optimized by a suitable choice of the intensity ratio.

  7. Radiative cooling of relativistic electron beams

    International Nuclear Information System (INIS)

    Modern high-energy particle accelerators and synchrotron light sources demand smaller and smaller beam emittances in order to achieve higher luminosity or better brightness. For light particles such as electrons and positrons, radiation damping is a natural and effective way to obtain low emittance beams. However, the quantum aspect of radiation introduces random noise into the damped beams, yielding equilibrium emittances which depend upon the design of a specific machine. In this dissertation, the author attempts to make a complete analysis of the process of radiation damping and quantum excitation in various accelerator systems, such as bending magnets, focusing channels and laser fields. Because radiation is formed over a finite time and emitted in quanta of discrete energies, he invokes the quantum mechanical approach whenever the quasiclassical picture of radiation is insufficient. He shows that radiation damping in a focusing system is fundamentally different from that in a bending system. Quantum excitation to the transverse dimensions is absent in a straight, continuous focusing channel, and is exponentially suppressed in a focusing-dominated ring. Thus, the transverse normalized emittances in such systems can in principle be damped to the Compton wavelength of the electron, limited only by the Heisenberg uncertainty principle. In addition, he investigates methods of rapid damping such as radiative laser cooling. He proposes a laser-electron storage ring (LESR) where the electron beam in a compact storage ring repetitively interacts with an intense laser pulse stored in an optical resonator. The laser-electron interaction gives rise to rapid cooling of electron beams and can be used to overcome the space charge effects encountered in a medium energy circular machine. Applications to the designs of low emittance damping rings and compact x-ray sources are also explored

  8. Boosting runtime-performance of photon pencil beam algorithms for radiotherapy treatment planning.

    Science.gov (United States)

    Siggel, M; Ziegenhein, P; Nill, S; Oelfke, U

    2012-10-01

    Pencil beam algorithms are still considered as standard photon dose calculation methods in Radiotherapy treatment planning for many clinical applications. Despite their established role in radiotherapy planning their performance and clinical applicability has to be continuously adapted to evolving complex treatment techniques such as adaptive radiation therapy (ART). We herewith report on a new highly efficient version of a well-established pencil beam convolution algorithm which relies purely on measured input data. A method was developed that improves raytracing efficiency by exploiting the capability of modern CPU architecture for a runtime reduction. Since most of the current desktop computers provide more than one calculation unit we used symmetric multiprocessing extensively to parallelize the workload and thus decreasing the algorithmic runtime. To maximize the advantage of code parallelization, we present two implementation strategies - one for the dose calculation in inverse planning software, and one for traditional forward planning. As a result, we could achieve on a 16-core personal computer with AMD processors a superlinear speedup factor of approx. 18 for calculating the dose distribution of typical forward IMRT treatment plans. PMID:22071169

  9. Development of 'Beam Color' radiation indicators

    International Nuclear Information System (INIS)

    In recent years, the industrial application of radiation has expanded from the cross-linking of polymers for electric wires and thermal contraction tubes to food irradiation and the sterilization of medical products and instruments. Although the dosimeters used for these radiation applications consist mostly of cellulose triacetate films, as they measure radiation dose by the change of light absorbance, they are not simple and easy to use. Sumitomo Electric Industries Ltd. has developed a simple dosimeter which utilizes the generation of hydrogen chloride occurring when polyvinyl chloride is irradiated. Radiation dose is determined by the change of color due to the change of pH using pH-indicating dyes. As the results of examining various combinations of pH-indicating dyes, it was able to develop the combination which changes color continuously with radiation dose, and which changes color at a specific radiation dose. In addition, by combining these pH-indicating dyes with a PVC stabilizer, it was able to develop the method for causing the change of dye color at a designated radiation dose. Based on these findings, 'Beam Color' radiation indicating labels and radiation color-changing ink are marketed. Thus radiation dose can be determined quickly and easily. (Kako, I.)

  10. Laser synchrotron radiation and beam cooling

    Energy Technology Data Exchange (ETDEWEB)

    Esarey, E.; Sprangle, P.; Ting, A. [Naval Research Lab., Washington, DC (United States)] [and others

    1995-12-31

    The interaction of intense {approx_gt} 10{sup 18} W/cm{sup 2}, short pulse ({approx_lt} 1 ps) lasers with electron beams and plasmas can lead to the generation of harmonic radiation by several mechanisms. Laser synchrotron radiation may provide a practical method for generating tunable, near monochromatic, well collimated, short pulse x-rays in compact, relatively inexpensive source. The mechanism for the generation of laser synchrotron radiation is nonlinear Thomson scattering. Short wavelengths can be generated via Thomson scattering by two methods, (i) backscattering from relativistic electron beams, in which the radiation frequency is upshifted by the relativistic factor 4{gamma}{sup 2}, and (ii) harmonic scattering, in which a multitude of harmonics are generated with harmonic numbers extending out to the critical harmonic number nc{approx_equal}a{sub 0}{sup 3} {much_gt} 1, where a{sub 0} {approx_equal}10{sup -9}{lambda}I{sup 1/2}, {lambda} is the laser wavelength in {mu}m and I is the laser intensity in W/cm{sup 2}. Laser synchrotron sources are capable of generating short ({approx_lt} ps) x-ray pulses with high peak flux ({approx_gt} 10{sup 21} photons/s) and brightness ({approx_gt}{sup 19} photons/s-mm{sup 2}-mrad{sup 2} 0.1%BW. As the electron beam radiates via Thomson scattering, it can subsequently be cooled, i.e., the beam emittance and energy spread can be reduced. This cooling can occur on rapid ({approximately} ps) time scales. In addition, electron distributions with sufficiently small axial energy spreads can be used to generate coherent XUV radiation via a laser-pumped FEL mechanism.

  11. Does Axillary Boost Increase Lymphedema Compared With Supraclavicular Radiation Alone After Breast Conservation?

    International Nuclear Information System (INIS)

    Purpose: To determine independent predictors of lymphedema (LE) after breast radiotherapy and to quantify added risks of LE from regional node irradiation (RNI). Materials and Methods: A total of 2,579 women with T1-2, N 0-3, M0 breast cancer treated with breast conservation between 1970 and 2005 were studied. A total of 2,169 patients (84%) received radiation to the breast (B), 226 (8.8%) to the breast and supraclavicular LNs (B+SC), and 184 (7.1%) to the breast, supraclavicular LNs, and a posterior axillary boost (B+SC+PAB). Median follow-up was 81 months (range, 3-271). Results: Eighteen percent of patients developed LE. LE risks were as follows: 16% (B), 23% (B+SC), and 31% (B+SC+PAB) (p < 0.0001). LE severity was greater in patients who had RNI (p = 0.0002). On multivariate analysis, RT field (p < 0.0001), obesity index (p = 0.0157), systemic therapy (p = 0.0013), and number of LNs dissected (p < 0.0001) independently predicted for LE. In N1 patients, the addition of a SC to tangents (p < 0.0001) and the addition of a PAB to tangents (p = 0.0017) conferred greater risks of LE, but adding a PAB to B+SC RT did not (p = 0.8002). In the N2 patients, adding a PAB increased the risk of LE 4.5-fold over B+SC RT (p = 0.0011). Conclusions: LE predictors included number of LNs dissected, RNI, obesity index, and systemic therapy. LE risk increased when a SC or PAB were added in the N1 subgroup. In the N2 patients, a PAB increased the risk over B+SC. The decision to boost the axilla must be weighed against the increased risk of LE that it imposes

  12. Whole brain radiotherapy: Prognostic factors and results of a radiation boost delivered through a conventional linear accelerator

    International Nuclear Information System (INIS)

    Purpose: Assess prognostic factors for overall survival and the potential benefit of a boost in patients treated with whole brain radiation therapy (WBRT). Methods and materials: From 2002 to 2006, a retrospective analysis was made from 250 unselected consecutive patients with secondary brain metastases from lung cancer, breast cancer and melanoma. Eighteen patients received surgery and were excluded from analysis. Four potential prognostic factors have been studied: primary tumor type, gender, number of metastases and improvement of neurological symptoms after radiation therapy. A subgroup analysis was performed to determine whether an additional boost could potentially improve outcome in patients who presented with less than three metastases, performance status <2, and no surgical resection of their metastasis. Results: Average follow-up was 10.3 months. Median overall survival was 5.6 months and survival rates at 1 and 2 years were 22.7% and 10%, respectively. Age less than 65 (p < 0.01), neurological improvement after WBRT (p < 0.01), and presence of less than three metastases were significant factors for overall survival in multivariate analysis. When focusing on the selected subgroup (120 assessable patients), median overall survival was 4.0 months in patients with no radiation boost, versus 8.9 months in patients with radiation boost (p = 0.0024). Conclusions: Survival and prognostic factors were similar to those found in the literature. Boost delivered after WBRT by a conventional particle accelerator could provide a benefit in selected patients, especially for centers that do not have radiotherapy techniques in stereotactic conditions. This warrants further prospective assessment.

  13. Repeat Whole Brain Radiation Therapy with a Simultaneous Infield Boost: A Novel Technique for Reirradiation

    International Nuclear Information System (INIS)

    The treatment of patients who experience intracranial progression after whole brain radiation therapy (WBRT) is a clinical challenge. Novel radiation therapy delivery technologies are being applied with the objective of improving tumor and symptom control in these patients. The purpose of this study is to describe the clinical outcomes of the application of a novel technology to deliver repeat WBRT with volume modulated arc therapy (VMAT) and a simultaneous infield boost (WB-SIB) to gross disease. A total of 16 patients were initially treated with WBRT between 2000 and 2008 and then experienced intracranial progression, were treated using repeat WB-SIB, and were analyzed. The median dose for the first course of WBRT was 35 Gy (range: 30–50.4 Gy). Median time between the initial course of WBRT and repeat WB-SIB was 11.3 months. The median dose at reirradiation was 20 Gy to the whole brain with a median boost dose of 30 Gy to gross disease. A total of 2 patients demonstrated radiographic disease progression after treatment. The median overall survival (OS) time from initial diagnosis of brain metastases was 18.9 months (range: 7.1–66.6 (95% CI: 0.8–36.9)). The median OS time after initiation of reirradiation for all patients was 2.7 months (range: 0.46–14.46 (95% CI: 1.3–8.7)). Only 3 patients experienced CTCAE grade 3 fatigue. No other patients experienced any ≥ CTCAE grade 3 toxicity. This analysis reports the result of a novel RT delivery technique for the treatment of patients with recurrent brain metastases. Side effects were manageable and comparable to other conventional repeat WBRT series. Repeat WB-SIB using the VMAT RT delivery technology is feasible and appears to have acceptable short-term acute toxicity. These results may provide a foundation for further exploration of the WB-SIB technique for repeat WBRT in future prospective clinical trials.

  14. Clinical Response of Pelvic and Para-aortic Lymphadenopathy to a Radiation Boost in the Definitive Management of Locally Advanced Cervical Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Rash, Dominique L. [Department of Radiation Oncology, University of California Davis Medical Center, Sacramento, California (United States); Lee, Yongsook C. [Department of Radiation Oncology, University of Kansas School of Medicine, Kansas City, Kansas (United States); Kashefi, Amir [Division of Nuclear Medicine, Department of Radiology, University of California Davis Medical Center, Sacramento, California (United States); Durbin-Johnson, Blythe [Division of Biostatistics, Department of Public Health Sciences, University of California Davis School of Medicine, Sacramento, California (United States); Mathai, Mathew; Valicenti, Richard [Department of Radiation Oncology, University of California Davis Medical Center, Sacramento, California (United States); Mayadev, Jyoti S., E-mail: jyoti.mayadev@ucdmc.ucdavis.edu [Department of Radiation Oncology, University of California Davis Medical Center, Sacramento, California (United States)

    2013-10-01

    Purpose: Optimal treatment with radiation for metastatic lymphadenopathy in locally advanced cervical cancer remains controversial. We investigated the clinical dose response threshold for pelvic and para-aortic lymph node boost using radiographic imaging and clinical outcomes. Methods and Materials: Between 2007 and 2011, 68 patients were treated for locally advanced cervical cancer; 40 patients had clinically involved pelvic and/or para-aortic lymph nodes. Computed tomography (CT) or 18F-labeled fluorodeoxyglucose-positron emission tomography scans obtained pre- and postchemoradiation for 18 patients were reviewed to assess therapeutic radiographic response of individual lymph nodes. External beam boost doses to involved nodes were compared to treatment response, assessed by change in size of lymph nodes by short axis and change in standard uptake value (SUV). Patterns of failure, time to recurrence, overall survival (OS), and disease-free survival (DFS) were determined. Results: Sixty-four lymph nodes suspicious for metastatic involvement were identified. Radiation boost doses ranged from 0 to 15 Gy, with a mean total dose of 52.3 Gy. Pelvic lymph nodes were treated with a slightly higher dose than para-aortic lymph nodes: mean 55.3 Gy versus 51.7 Gy, respectively. There was no correlation between dose delivered and change in size of lymph nodes along the short axis. All lymph nodes underwent a decrease in SUV with a complete resolution of abnormal uptake observed in 68%. Decrease in SUV was significantly greater for lymph nodes treated with ≥54 Gy compared to those treated with <54 Gy (P=.006). Median follow-up was 18.7 months. At 2 years, OS and DFS for the entire cohort were 78% and 50%, respectively. Locoregional control at 2 years was 84%. Conclusions: A biologic response, as measured by the change in SUV for metastatic lymph nodes, was observed at a dose threshold of 54 Gy. We recommend that involved lymph nodes be treated to this minimum dose.

  15. Radiation damping in pulsed Gaussian beams

    CERN Document Server

    Harvey, Chris

    2011-01-01

    We consider the effects of radiation damping on the electron dynamics in a Gaussian beam model of a laser field. For high intensities, i.e. with dimensionless intensity a0 \\gg 1, it is found that the dynamics divide into three regimes. For low energy electrons (low initial {\\gamma}-factor, {\\gamma}0) the radiation damping effects are negligible. At higher energies, but still at 2{\\gamma}0 a0 one is in a regime of radiation reaction induced electron capture. This capture is found to be stable with respect to the spatial properties of the electron beam and results in a significant energy loss of the electrons. In this regime the plane wave model of the laser field provides a good description of the dynamics, whereas for lower energies the Gaussian beam and plane wave models differ significantly. Finally the dynamics are considered for the case of an XFEL field. It is found that the significantly lower intensities of such fields inhibits the damping effects.

  16. A beam radiation monitoring and protection system for AGS secondary beams

    International Nuclear Information System (INIS)

    A commercially available radiation monitor using a scintillation detector was modified for charged particle beam monitoring. The device controls access to secondary beams of the AGS and limits beam intensity

  17. Simulating relativistic beam and plasma systems using an optimal boosted frame

    International Nuclear Information System (INIS)

    It was shown recently that it may be computationally advantageous to perform computer simulations in a Lorentz boosted frame for a certain class of systems. However, even if the computer model relies on a covariant set of equations, it was pointed out that algorithmic difficulties related to discretization errors may have to be overcome in order to take full advantage of the potential speedup. In this paper, we summarize the findings, the difficulties and their solutions, and review the applications of the technique that have been performed to date.

  18. Radiative transfer simulations of magnetar flare beaming

    CERN Document Server

    van Putten, T; Baring, M G; Wijers, R A M J

    2016-01-01

    Magnetar giant flares show oscillatory modulations in the tails of their light curves, which can only be explained via some form of beaming. The fireball model for magnetar bursts has been used successfully to fit the phase-averaged light curves of the tails of giant flares, but so far no attempts have been made to fit the pulsations. We present a relatively simple numerical model to simulate beaming of magnetar flare emission. In our simulations, radiation escapes from the base of a fireball trapped in a dipolar magnetic field, and is scattered through the optically thick magnetosphere of the magnetar until it escapes. Beaming is provided by the presence of a relativistic outflow, as well as by the geometry of the system. We find that a simple picture for the relativistic outflow is enough to create the pulse fraction and sharp peaks observed in pulse profiles of magnetar flares, while without a relativistic outflow the beaming is insufficient to explain giant flare rotational modulations.

  19. Helical relativistic electron beam and THz radiation

    CERN Document Server

    Son, S

    2011-01-01

    A THz laser generation utilizing a helical relativistic electron beam propagating through a strong magnetic field is discussed. The initial amplification rate in this scheme is much stronger than that in the conventional free electron laser. A magnetic field of the order of Tesla can yield a radiation in the range of 0.5 to 3 THz, corresponding to the total energy of mJ and the duration of tens of pico-second, or the temporal power of the order of GW.

  20. Summary of session 3 on synchrotron radiation and beam dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, V.; /Fermilab; Metral, E.; /CERN

    2010-12-01

    We summarize presentations, discussions and general conclusions of the Workshop session on 'Beam Dynamics Issues'. Major subjects include effects due to synchrotron radiation (SR), cryogenic loads, electron cloud, impedances, intra-beam scattering (IBS) and beam-beam interactions.

  1. Cosmetic Outcome and Seroma Formation After Breast-Conserving Surgery With Intraoperative Radiation Therapy Boost for Early Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Senthi, Sashendra, E-mail: sashasenthi@msn.com [Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne (Australia); Link, Emma [Centre for Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, Melbourne (Australia); Chua, Boon H. [Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne (Australia); University of Melbourne, Melbourne (Australia)

    2012-10-01

    Purpose: To evaluate cosmetic outcome and its association with breast wound seroma after breast-conserving surgery (BCS) with targeted intraoperative radiation therapy (tIORT) boost for early breast cancer. Methods and Materials: An analysis of a single-arm prospective study of 55 patients with early breast cancer treated with BCS and tIORT boost followed by conventional whole breast radiation therapy (WBRT) between August 2003 and January 2006 was performed. A seroma was defined as a fluid collection at the primary tumor resection site identified clinically or radiologically. Cosmetic assessments using the European Organization for Research and Treatment of Cancer rating system were performed at baseline before BCS and 30 months after WBRT was completed. Results: Twenty-eight patients (51%) developed a seroma, with 18 patients (33%) requiring at least 1 aspiration. Tumor location was significantly associated with seroma formation (P=.001). Ten of 11 patients with an upper inner quadrant tumor developed a seroma. Excellent or good overall cosmetic outcome at 30 months was observed in 34 patients (62%, 95% confidence interval 53%-80%). Seroma formation was not associated with the overall cosmetic result (P=.54). Conclusion: BCS with tIORT boost followed by WBRT was associated with an acceptable cosmetic outcome. Seroma formation was not significantly associated with an adverse cosmetic outcome.

  2. Cosmetic Outcome and Seroma Formation After Breast-Conserving Surgery With Intraoperative Radiation Therapy Boost for Early Breast Cancer

    International Nuclear Information System (INIS)

    Purpose: To evaluate cosmetic outcome and its association with breast wound seroma after breast-conserving surgery (BCS) with targeted intraoperative radiation therapy (tIORT) boost for early breast cancer. Methods and Materials: An analysis of a single-arm prospective study of 55 patients with early breast cancer treated with BCS and tIORT boost followed by conventional whole breast radiation therapy (WBRT) between August 2003 and January 2006 was performed. A seroma was defined as a fluid collection at the primary tumor resection site identified clinically or radiologically. Cosmetic assessments using the European Organization for Research and Treatment of Cancer rating system were performed at baseline before BCS and 30 months after WBRT was completed. Results: Twenty-eight patients (51%) developed a seroma, with 18 patients (33%) requiring at least 1 aspiration. Tumor location was significantly associated with seroma formation (P=.001). Ten of 11 patients with an upper inner quadrant tumor developed a seroma. Excellent or good overall cosmetic outcome at 30 months was observed in 34 patients (62%, 95% confidence interval 53%-80%). Seroma formation was not associated with the overall cosmetic result (P=.54). Conclusion: BCS with tIORT boost followed by WBRT was associated with an acceptable cosmetic outcome. Seroma formation was not significantly associated with an adverse cosmetic outcome.

  3. Design and development of radiation absorber for sighting beam line

    International Nuclear Information System (INIS)

    During the commissioning of Indus-2 , it is necessary to view the synchrotron radiation that will be emanating from the dipole exit ports. The 100 beam line from dipole 11 was earmarked for sighting beam line. The synchrotron radiation power density would be around 340 watts on the photon absorber inside the radiation absorber module, at the specified beam power of Indus-2. The beam striking on this photon absorber produces x-rays and Bremsstrahlung radiation. These are to be stopped and absorbed by radiation absorber. The photon absorber and the radiation absorber are integrated in a single vacuum chamber and actuated by a pneumatic cylinder connected using a bellow. Radiation absorber was needed to isolate the diagnostic components and to protect them from radiation a well as heat when they were not in use. The paper describes the design, calculation and development of the dynamic photon cum radiation absorber. The ultimate vacuum performance is also described. (author)

  4. Coherent Radiation from Relativistic Electron Beams.

    Science.gov (United States)

    Chen, Kuan-Ren

    Two new laser concepts, the Ion-Ripple Laser (IRL) and the Ion-Channel Laser (ICL), are proposed. A unified theory for coherent radiation from relativistic electron beams devices is developed; the theory not only links the physics of Cyclotron Masers (CMs) and Free Electron Lasers (FELs) but covers the physics of the IRLs and the ICLs. We have also invented a new numerical method, the Neo-Finite -Difference (NFD) method, for electromagnetic plasma simulations and applied it to studies of these lasers. The unified amplification theory compares the growth mechanisms. Two bunching mechanisms (both axial and azimuthal) exist, not only for the noncollective single electron resonance regime, but also in the collective gain regime. Competition or reinforcement between the two bunching mechanisms is determined by the q value (a parameter that determines how the electron oscillation frequency depends on energy), the electron axial velocity, and the wave phase velocity. The unified theory concludes that, for wave amplification, the sign of the electron mismatch frequency is required to be the same as the sign of a bunching parameter that is determined by the total bunching. In an IRL, a relativistic electron beam propagates obliquely through an ion ripple in a plasma. The radiation frequency depends on the beam energy, the ripple wave number, and the angle: omega ~ 2gamma ^{2}k_{ir}ccos theta. By proper choice of device parameters, sources of microwaves, optical, and perhaps even X-rays can be made. The dispersion relation for wave coupling is derived and used to calculate the radiation frequency and linear growth rate. The nonlinear saturation mechanism is explored. Computer simulation is used to verify the ideas, scaling laws and nonlinear mechanisms. In an ICL, the ion focusing force causes the electrons to oscillate about the channel axis and plays a similar role to the magnetic field in a CM. This electron motion is nonlinear and is studied. Simulations were performed

  5. Simultaneous integrated boost-intensity modulated radiation therapy for inoperable hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Hyun; Park, Joong-Won; Kim, Yeon-Joo; Kim, Bo Hyun; Woo, Sang Myung; Moon, Sung Ho; Kim, Sang Soo; Lee, Woo Jin; Kim, Dae Yong; Kim, Chang-Min [National Cancer Center, Center for Liver Cancer, Research Institute and Hospital, Goyang-si, Gyeonggi-do (Korea, Republic of)

    2014-10-15

    The aim of this work was to evaluate the clinical efficacy and safety of simultaneous integrated boost-intensity modulated radiation therapy (SIB-IMRT) in patients with inoperable hepatocellular carcinoma (HCC). A total of 53 patients with inoperable HCC underwent SIB-IMRT using two dose-fractionation schemes, depending on the proximity of gastrointestinal structures. The 41 patients in the low dose-fractionation (LD) group, with internal target volume (ITV) < 1 cm from gastrointestinal structures, received total doses of 55 and 44 Gy in 22 fractions to planning target volume 1 (PTV1) and 2 (PTV2), respectively. The 12 patients in the high dose-fractionation (HD) group, with ITV ≥ 1 cm from gastrointestinal structures, received total doses of 66 and 55 Gy in 22 fractions to the PTV1 and PTV2, respectively. Overall, treatment was well tolerated, with no grade > 3 toxicity. The LD group had larger sized tumors (median: 6 vs. 3.4 cm) and greater frequencies of vascular invasion (80.6 vs. 16.7 %) than patients in the HD group (p < 0.05 each). The median overall survival (OS) was 25.1 months and the actuarial 2-year local progression-free survival (LPFS), relapse-free survival (RFS), and OS rates were 67.3, 14.7, and 54.7 %, respectively. The HD group tended to show better tumor response (100 vs. 62.2 %, p = 0.039) and 2-year LPFS (85.7 vs. 59 %, p = 0.119), RFS (38.1 vs. 7.3 %, p = 0.063), and OS (83.3 vs. 44.3 %, p = 0.037) rates than the LD group. Multivariate analysis showed that tumor response was significantly associated with OS. SIB-IMRT is feasible and safe for patients with inoperable HCC. (orig.) [German] Ziel der Arbeit war es, die klinische Wirksamkeit und die Sicherheit der intensitaetsmodulierten Radiotherapie mit simultanem integriertem Boost (SIB-IMRT) fuer Patienten mit einem inoperablen hepatozellulaeren Karzinom (HCC) zu evaluieren. Bei 53 Patienten mit inoperablem HCC wurden zwei unterschiedliche Dosierungskonzepte je nach Lagebeziehung des

  6. External beam radiation therapy for prostate cancer

    International Nuclear Information System (INIS)

    Purpose/Objectives: The intent of this course is to review the issues involved in the management of non-metastatic adenocarcinoma of the prostate. -- The value of pre-treatment prognostic factors including stage, grade and PSA value will be presented, and their value in determining therapeutic strategies will be discussed. -- Controversies involving the simulation process and treatment design will be presented. The value of CT scanning, Beams-Eye View, 3-D planning, intravesicle, intraurethral and rectal contrast will be presented. The significance of prostate and patient movement and strategies for dealing with them will be presented. -- The management of low stage, low to intermediate grade prostate cancer will be discussed. The dose, volume and timing of irradiation will be discussed as will the role of neo-adjuvant hormonal therapy, neutron irradiation and brachytherapy. The current status of radical prostatectomy and cryotherapy will be summarized. Treatment of locally advanced, poorly differentiated prostate cancer will be presented including a discussion of neo-adjuvant and adjuvant hormones, dose-escalation and neutron irradiation. -- Strategies for post-radiation failures will be presented including data on cryotherapy, salvage prostatectomy and hormonal therapy (immediate, delayed and/or intermittent). New areas for investigation will be reviewed. -- The management of patients post prostatectomy will be reviewed. Data on adjuvant radiation and therapeutic radiation for biochemical or clinically relapsed patients will be presented. This course hopes to present a realistic and pragmatic overview for treating patients with non-metastatic prostatic cancer

  7. The dynamics of radiation damage by focused ion beams in the ion beam synthesis

    International Nuclear Information System (INIS)

    The following topics were covered: direct ion implantation, focused ion beams, cobalt silicides (CoSi2), RBS, ion beam synthesis, CoSi2 ion beam synthesis by focused ion beams in Si(111), germanium FIB implantation in Si(111), radiation damage at FIB implantation, models and simulation. (WL)

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

    International Nuclear Information System (INIS)

    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. Radiation shielding of the beam absorber in the MI 8-GeV beam line

    Energy Technology Data Exchange (ETDEWEB)

    Rakhno, I.; /Fermilab

    2006-01-01

    Results of Monte Carlo radiation shielding calculations performed for the beam absorber of the MI 8 GeV beam line are presented and discussed. The possibility to reach the level of 10{sup 19} protons per year is investigated.

  10. Radiation sterilization of gelatin with electron beam

    International Nuclear Information System (INIS)

    The radiation sterilization of gelatin contaminated with 4 x 103 to 4 x 106 bacteria per gram was investigated with electron beam from a JJ-2 accelerator. After treatment with the doses of 3-4 kGy, the initial microbial counts in the gelatin could be approximately reduced by two orders of magnitude and the coliforms were substantively killed at the same time. The viscosities, transparencies and major gelatin compositions of the irradiated gelatin (with doses of 1.5-10 kGy) and the control sample were determined. The results show that the viscosity of the gelatin solution decreases gradually with the increase of the irradiation doses, the irradiation degradation of the gelatin molecules can not be decreased under the condition of nitrogen atomosphere of lower irradiation temperature, and the amino acid contents of the gelatin irradiated do not undergo any marked changes in comparison with the control sample except for cystine

  11. Transverse beam shape measurements of intense proton beams using optical transition radiation

    Energy Technology Data Exchange (ETDEWEB)

    Scarpine, Victor E.; /Fermilab

    2012-03-01

    A number of particle physics experiments are being proposed as part of the Department of Energy HEP Intensity Frontier. Many of these experiments will utilize megawatt level proton beams onto targets to form secondary beams of muons, kaons and neutrinos. These experiments require transverse size measurements of the incident proton beam onto target for each beam spill. Because of the high power levels, most beam intercepting profiling techniques will not work at full beam intensity. The possibility of utilizing optical transition radiation (OTR) for high intensity proton beam profiling is discussed. In addition, previous measurements of OTR beam profiles from the NuMI beamline are presented.

  12. EXAFS-spectroscopy on synchrotron radiation beam

    CERN Document Server

    Aksenov, V L; Kuzmin, A Y; Purans, Y

    2001-01-01

    In the review the basis theoretical principles of EXAFS spectroscopy are given, as one of principal directions of an absorption spectroscopy permitting with a high accuracy to gain parameters of the short-range order in multicomponent amorphous and quasi-crystal mediums. The methods of the analysis of EXAFS spectra with allowance of effects of multiply scattering are featured. The exposition of the experimental set-ups, which realize the method of EXAFS spectroscopy on beams of SR, requirement of the monochromatization of radiation beams are given. For investigation of phase transition and external effects the energy-dispersive EXAFS spectrometer is creating at the National center of SR Kurchatov Institute which can measure the EXAFS spectrum with a time resolution 3-5 ms. The experimental results on investigation (by the EXAFS spectroscopy method) of oxides of tungsten and molybdenum are given, which have unique property: the variable valence of an ion of metal is depending on external action. The most inter...

  13. Anomalous x-ray radiation of beam plasma

    International Nuclear Information System (INIS)

    The properties of non-equilibrium stationary plasma under the conditions of the planned plasma-chemical reactors based on beam-plasma discharge were investigated. The x-ray spectrum of the beam-plasma was measured and anomalous spectral properties were analyzed. Starting with some critical pressure the anomalous radiation was added to the classical bremsstrahlung spectrum. The occurrence of anomalous radiation can be used to diagnose the condition of beam transportation in such systems. (D.Gy.)

  14. The use of intensity-modulated radiation therapy photon beams for improving the dose uniformity of electron beams shaped with MLC

    International Nuclear Information System (INIS)

    Electrons are ideal for treating shallow tumors and sparing adjacent normal tissue. Conventionally, electron beams are collimated by cut-outs that are time-consuming to make and difficult to adapt to tumor shape throughout the course of treatment. We propose that electron cut-outs can be replaced using photon multileaf collimator (MLC). Two major problems of this approach are that the scattering of electrons causes penumbra widening because of a large air gap, and available commercial treatment planning systems (TPSs) do not support MLC-collimated electron beams. In this study, these difficulties were overcome by (1) modeling electron beams collimated by photon MLC for a commercial TPS, and (2) developing a technique to reduce electron beam penumbra by adding low-energy intensity-modulated radiation therapy (IMRT) photons (4 MV). We used blocks to simulate MLC shielding in the TPS. Inverse planning was used to optimize boost photon beams. This technique was applied to a parotid and a central nervous system (CNS) clinical case. Combined photon and electron plans were compared with conventional plans and verified using ion chamber, film, and a 2D diode array. Our studies showed that the beam penumbra for mixed beams with 90 cm source to surface distance (SSD) is comparable with electron applicators and cut-outs at 100 cm SSD. Our mixed-beam technique yielded more uniform dose to the planning target volume and lower doses to various organs at risk for both parotid and CNS clinical cases. The plans were verified with measurements, with more than 95% points passing the gamma criteria of 5% in dose difference and 5 mm for distance to agreement. In conclusion, the study has demonstrated the feasibility and potential advantage of using photon MLC to collimate electron beams with boost photon IMRT fields.

  15. Cellular effects after exposure to mixed beams of ionizing radiation

    OpenAIRE

    Staaf, Elina

    2012-01-01

    Mixed beams of ionizing radiation in our environment originate from space, the bedrock and our own houses. Radiotherapy patients treated with boron neutron capture therapy or with high energy photons are also exposed to mixed beams of gamma radiation and neutrons. Earlier investigations have reported additivity as well as synergism (a greater than additive response) when combining radiations of different linear energy transfer. However, the outcome seemed to be dependent on the experimental s...

  16. Concomitant boost radiation therapy for inoperable non-small-cell lung cancer: preliminary report of a prospective randomized study

    International Nuclear Information System (INIS)

    Purpose: The radiation therapy results for patients with inoperable non-small-cell lung cancer (NSCLC) have been disappointing. Tumor dose escalation using concomitant boost technique (CBT) has been shown to improve local control in a few prospective studies. This trial was carried out to prospectively assess the radiation response and acute toxicity of CBT in comparison to the conventional treatment technique (CTT). Methods and Materials: Ninety-seven consecutive eligible patients were entered in this prospective clinical trial between November 1994 and February 1998. Patients were randomized to receive either CBT (43 patients) or CTT (54 patients) radiation therapy. These patients either refused chemotherapy or were judged as unsuitable for chemotherapy. Patients in the CBT group received 46.8 Gy in 26 fractions using large fields that encompassed the gross and occult disease. A concomitant boost of 18.2 Gy (0.7 Gy per fraction) was delivered to the gross disease using small fields with 1.5-cm margins. The small fields were treated concurrently with the large fields and the total dose to the tumor area was 65 Gy in 26 fractions. Patients in the CTT group received 70.8 Gy in 38 fractions. The acute toxicity between each group was compared. The response rate was analyzed and compared by treatment group, gender, age, stage, histology, initial Karnofsky performance score (KPS), severity of acute toxicity, and maximum body weight loss (MBWL) during treatment course. Results: The demographic parameters such as sex, age, and stage were evenly distributed in each treatment group. The majority of these patients had Stage IIIA and IIIB disease. Overall median treatment times were 39 days for the CBT group of patients and 62 days for the CTT group. No treatment-related mortality was found. There were 2 patients in the CTT group with acute RTOG Grade 3 lung toxicity, and no Grade 3 lung or esophageal toxicity was observed in CBT group. The response rates, assessed by

  17. Two Effective Heuristics for Beam Angle Optimization in Radiation Therapy

    CERN Document Server

    Yarmand, Hamed

    2013-01-01

    In radiation therapy, mathematical methods have been used for optimizing treatment planning for delivery of sufficient dose to the cancerous cells while keeping the dose to critical surrounding structures minimal. This optimization problem can be modeled using mixed integer programming (MIP) whose solution gives the optimal beam orientation as well as optimal beam intensity. The challenge, however, is the computation time for this large scale MIP. We propose and investigate two novel heuristic approaches to reduce the computation time considerably while attaining high-quality solutions. We introduce a family of heuristic cuts based on the concept of 'adjacent beams' and a beam elimination scheme based on the contribution of each beam to deliver the dose to the tumor in the ideal plan in which all potential beams can be used simultaneously. We show the effectiveness of these heuristics for intensity modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT) on a clinical liver case.

  18. Treatment of breast cancer with simultaneous integrated boost in hybrid plan technique. Influence of flattening filter-free beams

    Energy Technology Data Exchange (ETDEWEB)

    Bahrainy, Marzieh; Kretschmer, Matthias; Joest, Vincent; Kasch, Astrid; Wuerschmidt, Florian; Dahle, Joerg; Lorenzen, Joern [Radiologische Allianz, Hamburg (Germany)

    2016-05-15

    The present study compares in silico treatment plans using hybrid plan technique during hypofractionated radiation of mammary carcinoma with simultaneous integrated boost (SIB). The influence of 6 MV photon radiation in flattening filter free (FFF) mode against the clinical standard flattening filter (FF) mode is to be examined. RT planning took place with FF and FFF radiation plans for 10 left-sided breast cancer patients. Hybrid plans were realised with two tangential IMRT fields and one VMAT field. The dose prescription was in line with the guidelines in the ARO-2010-01 study. The dosimetric verification took place with a manufacturer-independent measurement system. Required dose prescriptions for the planning target volumes (PTV) were achieved for both groups. The average dose values of the ipsi- and contralateral lung and the heart did not differ significantly. The overall average incidental dose to the left anterior descending artery (LAD) of 8.24 ± 3.9 Gy in the FFF group and 9.05 ± 3.7 Gy in the FF group (p < 0.05) were found. The dosimetric verifications corresponded to the clinical requirements. FFF-based RT plans reduced the average treatment time by 17 s/fraction. In comparison to the FF-based hybrid plan technique the FFF mode allows further reduction of the average LAD dose for comparable target volume coverage without adverse low-dose exposure of contralateral structures. The combination of hybrid plan technique and 6 MV photon radiation in the FFF mode is suitable for use with hypofractionated dose schemes. The increased dose rate allows a substantial reduction of treatment time and thus beneficial application of the deep inspiration breath hold technique. (orig.) [German] Vergleich der ''In-silico''-Bestrahlungsplaene der klinisch etablierten Hybridplan-Technik bei hypofraktionierter Bestrahlung des Mammakarzinoms mit simultan integriertem Boost (SIB). Untersucht wird der Einfluss von 6MV-Photonenstrahlung im Flattening

  19. Power Beaming Leakage Radiation as a SETI Observable

    CERN Document Server

    Benford, James N

    2016-01-01

    The most observable leakage radiation from an advanced civilization may well be from the use of power beaming to transfer energy and accelerate spacecraft. Applications suggested for power beaming involve Earth-to-space applications such as launching spacecraft to orbit, raising satellites to a higher orbit, and interplanetary concepts involving space-to-space transfers of cargo or passengers. We also quantify beam-driven launch to the outer solar system, interstellar precursors and ultimately starships. We estimate the principal observable parameters of power beaming leakage. Extraterrestrial civilizations would know their power beams could be observed, and so could put a message on the power beam and broadcast it for our receipt at little additional energy or cost. By observing leakage from power beams we may find a message embedded on the beam. Recent observations of the anomalous star KIC 8462852 by the Allen Telescope Array (ATA) set some limits on extraterrestrial power beaming in that system. We show t...

  20. Postoperative radiation boost does not improve local recurrence rates in extremity soft tissue sarcomas

    International Nuclear Information System (INIS)

    The standard of care for extremity soft tissue sarcomas continues to be negative-margin limb salvage surgery. Radiotherapy is frequently used as an adjunct to decrease local recurrence. No differences in survival have been found between preoperative and postoperative radiotherapy regimens. However, it is uncertain if the use of a postoperative boost in addition to preoperative radiotherapy reduces local recurrence rates. This retrospective review evaluated patients who received preoperative radiotherapy (n = 49) and patients who received preoperative radiotherapy with a postoperative boost (n=45). The primary endpoint analysed was local recurrence, with distant metastasis and death due to sarcoma analysed as secondary endpoints. Wilcoxon rank-sum test and either χ2 or Fisher's exact test were used to compare variables. Multivariable regression analyses were used to take into account potential confounders and identify variables that affected outcomes. No differences in the proportion or rate of local recurrence, distant metastasis or death due to sarcoma were observed between the two groups (P>0.05). The two groups were similarly matched with respect to demographics such as age, race and sex and tumour characteristics including excision status, tumour site, size, depth, grade, American Joint Committee on Cancer stage, chemotherapy receipt and histological subtype (P>0.05). The postoperative boost group had a larger proportion of patients with positive microscopic margins (62% vs 10%; P<0.001). No differences in rates of local recurrence, distant metastasis or death due to sarcoma were found in patients who received both pre- and postoperative radiotherapy when compared with those who received only preoperative radiotherapy.

  1. Ototoxicity evaluation in medulloblastoma patients treated with involved field boost using intensity-modulated radiation therapy (IMRT): a retrospective review

    International Nuclear Information System (INIS)

    Ototoxicity is a known side effect of combined radiation therapy and cisplatin chemotherapy for the treatment of medulloblastoma. The delivery of an involved field boost by intensity modulated radiation therapy (IMRT) may reduce the dose to the inner ear when compared with conventional radiotherapy. The dose of cisplatin may also affect the risk of ototoxicity. A retrospective study was performed to evaluate the impact of involved field boost using IMRT and cisplatin dose on the rate of ototoxicity. Data from 41 medulloblastoma patients treated with IMRT were collected. Overall and disease-free survival rates were calculated by Kaplan-Meier method Hearing function was graded according to toxicity criteria of Pediatric Oncology Group (POG). Doses to inner ear and total cisplatin dose were correlated with hearing function by univariate and multivariate data analysis. After a mean follow-up of 44 months (range: 14 to 72 months), 37 patients remained alive, with two recurrences, both in spine with CSF involvement, resulting in a disease free-survival and overall survival of 85.2% and 90.2%, respectively. Seven patients (17%) experienced POG Grade 3 or 4 toxicity. Cisplatin dose was a significant factor for hearing loss in univariate analysis (p < 0.03). In multivariate analysis, median dose to inner ear was significantly associated with hearing loss (p < 0.01). POG grade 3 and 4 toxicity were uncommon with median doses to the inner ear bellow 42 Gy (p < 0.05) and total cisplatin dose of less than 375 mg/m2 (p < 0.01). IMRT leads to a low rate of severe ototoxicity. Median radiation dose to auditory apparatus should be kept below 42 Gy. Cisplatin doses should not exceed 375 mg/m2

  2. Early-Stage Breast Cancer Treated With 3-Week Accelerated Whole-Breast Radiation Therapy and Concomitant Boost

    Energy Technology Data Exchange (ETDEWEB)

    Chadha, Manjeet, E-mail: MChadha@chpnet.org [Department of Radiation Oncology, Beth Israel Medical Center, New York, New York (United States); Woode, Rudolph; Sillanpaa, Jussi [Department of Radiation Oncology, Beth Israel Medical Center, New York, New York (United States); Lucido, David [Department of Biostatistics, Beth Israel Medical Center, New York, New York (United States); Boolbol, Susan K.; Kirstein, Laurie; Osborne, Michael P.; Feldman, Sheldon [Division of Breast Surgery, Beth Israel Medical Center, New York, New York (United States); Harrison, Louis B. [Department of Radiation Oncology, Beth Israel Medical Center, New York, New York (United States)

    2013-05-01

    Purpose: To report early outcomes of accelerated whole-breast radiation therapy with concomitant boost. Methods and Materials: This is a prospective, institutional review board-approved study. Eligibility included stage TisN0, T1N0, and T2N0 breast cancer. Patients receiving adjuvant chemotherapy were ineligible. The whole breast received 40.5 Gy in 2.7-Gy fractions with a concomitant lumpectomy boost of 4.5 Gy in 0.3-Gy fractions. Total dose to the lumpectomy site was 45 Gy in 15 fractions over 19 days. Results: Between October 2004 and December 2010, 160 patients were treated; stage distribution was as follows: TisN0, n=63; T1N0, n=88; and T2N0, n=9. With a median follow-up of 3.5 years (range, 1.5-7.8 years) the 5-year overall survival and disease-free survival rates were 90% (95% confidence interval [CI] 0.84-0.94) and 97% (95% CI 0.93-0.99), respectively. Five-year local relapse-free survival was 99% (95% CI 0.96-0.99). Acute National Cancer Institute/Common Toxicity Criteria grade 1 and 2 skin toxicity was observed in 70% and 5%, respectively. Among the patients with ≥2-year follow-up no toxicity higher than grade 2 on the Late Effects in Normal Tissues–Subjective, Objective, Management, and Analytic scale was observed. Review of the radiation therapy dose–volume histogram noted that ≥95% of the prescribed dose encompassed the lumpectomy target volume in >95% of plans. The median dose received by the heart D{sub 05} was 215 cGy, and median lung V{sub 20} was 7.6%. Conclusions: The prescribed accelerated schedule of whole-breast radiation therapy with concomitant boost can be administered, achieving acceptable dose distribution. With follow-up to date, the results are encouraging and suggest minimal side effects and excellent local control.

  3. Radiation signatures from an external relativist electron beam

    OpenAIRE

    Wee, Kyoum Bok

    1988-01-01

    X-band radiation has been observed which occurs when an electron beam travelling in air traverses an aluminum plate. The radiation pattern is more complicated than can be explained with a simplified model of Cerenkov radiation from air and transition radiation from the aluminum-air interface. The empirical observation is that the peak angle decreases with energy until about 70 MeV, then increases with energy. The angular width of the peak distribution shows a similar behavior with energy. The...

  4. Simultaneous radiochemotherapy versus concomitant boost radiation for advanced inoperable head and neck cancer

    International Nuclear Information System (INIS)

    In this prospective, non-randomized study we compare the results of simultaneous radiochemotherapy (RCT) with those of concomitant boost treatment (CBT) in advanced head and neck cancer. From January 1993 to March 1999, 77 patients were treated with cisplatin, 5-FU, and 70.2 Gy (accelerated split-course); from January 1995 to March 1999, a further 33 patients received CBT to a total dose of 72 Gy. Toxicities were prospectively recorded according to RTOG/EORTC criteria. Acute and subacute reactions did not differ significantly. Severe late effects (III/IV) remained anecdotal (one fistula). Therapy-associated mortalities were 3%(RCT) vs. 0% (CBT), most tumors responding well to therapy (CR + PR: RCT: 72%, CBT: 63%). The 2-year probabilities for freedom from locoregional progression amounted to 42% (RCT) and 31% (CBT); p > 0.05. Tumor-specific 2-year survival amounted to 40% (RCT) and 34% (CBT); p > 0.05. Both of the treatment concepts yield high remission rates with moderate toxicities. Nevertheless, median time to recurrence is still fairly short. We could not find any differences for local control and survival. For patients who are not able to complete the full three courses of radiochemotherapy, the concomitant boost schedule presents a good alternative

  5. Synchrotron radiation based beam diagnostics at the Fermilab Tevatron

    CERN Document Server

    Thurman-Keup, R; Hahn, A; Hurh, P; Lorman, E; Lundberg, C; Meyer, T; Miller, D; Pordes, S; Valishev, A

    2011-01-01

    Synchrotron radiation has been used for many years as a beam diagnostic at electron accelerators. It is not normally associated with proton accelerators as the intensity of the radiation is too weak to make detection practical. However, if one utilizes the radiation originating near the edge of a bending magnet, or from a short magnet, the rapidly changing magnetic field serves to enhance the wavelengths shorter than the cutoff wavelength, which for more recent high energy proton accelerators such as Fermilab's Tevatron, tends to be visible light. This paper discusses the implementation at the Tevatron of two devices. A transverse beam profile monitor images the synchrotron radiation coming from the proton and antiproton beams separately and provides profile data for each bunch. A second monitor measures the low-level intensity of beam in the abort gaps which poses a danger to both the accelerator's superconducting magnets and the silicon detectors of the high energy physics experiments. Comparisons of measur...

  6. Open Cell Conducting Foams for High Synchrotron Radiation Beam Liners

    OpenAIRE

    Petracca, Stefania; Stabile, Arturo

    2014-01-01

    The possible use of open-cell conductive foams in high synchrotron radiation particle accelerator beam liners is considered. Available materials and modeling tools are reviewed, potential pros and cons are discussed, and preliminary conclusions are drawn.

  7. Method for separating FEL output beams from long wavelength radiation

    Energy Technology Data Exchange (ETDEWEB)

    Neil, George; Shinn, Michelle D.; Gubeli, Joseph

    2016-04-26

    A method for improving the output beam quality of a free electron laser (FEL) by reducing the amount of emission at wavelengths longer than the electron pulse length and reducing the amount of edge radiation. A mirror constructed of thermally conductive material and having an aperture therein is placed at an oblique angle with respect to the beam downstream of the bending magnet but before any sensitive use of the FEL beam. The aperture in the mirror is sized to deflect emission longer than the wavelength of the FEL output while having a minor impact on the FEL output beam. A properly sized aperture will enable the FEL radiation, which is coherent and generally at a much shorter wavelength than the bending radiations, to pass through the aperture mirror. The much higher divergence bending radiations will subsequently strike the aperture mirror and be reflected safely out of the way.

  8. Beaming of particles and synchrotron radiation in relativistic magnetic reconnection

    CERN Document Server

    Kagan, Daniel; Piran, Tsvi

    2016-01-01

    Relativistic reconnection has been invoked as a mechanism for particle acceleration in numerous astrophysical systems. According to idealised analytical models reconnection produces a bulk relativistic outflow emerging from the reconnection sites (X-points). The resulting radiation is therefore highly beamed. Using two-dimensional particle-in-cell (PIC) simulations, we investigate particle and radiation beaming, finding a very different picture. Instead of having a relativistic average bulk motion with isotropic electron velocity distribution in its rest frame, we find that the bulk motion of particles in X-points is similar to their Lorentz factor gamma, and the particles are beamed within about 5/gamma. On the way from the X-point to the magnetic islands, particles turn in the magnetic field, forming a fan confined to the current sheet. Once they reach the islands they isotropise after completing a full Larmor gyration and their radiation is not strongly beamed anymore. The radiation pattern at a given freq...

  9. Beam focusing limitation from synchrotron radiation in two dimensions

    Science.gov (United States)

    Blanco, O. R.; Tomás, R.; Bambade, P.

    2016-02-01

    The Oide effect considers the synchrotron radiation in the final focusing quadrupole, and it sets a lower limit on the vertical beam size at the interaction point, particularly relevant for high-energy linear colliders. The theory of the Oide effect was derived considering only the second moment of the radiation in the focusing plane of the magnet. This article addresses the theoretical calculation of the radiation effect on the beam size considering the first and second moments of the radiation and both focusing and defocusing planes of the quadrupole. The effect for a Gaussian beam is referred to as 2D-Oide; however, an alternative beam size figure is given that could represent better the effect on the minimum achievable βy* . The CLIC 3 TeV final quadrupole (QD0) and beam parameters are used to compare the theoretical results from the Oide effect and the 2D-Oide effect with particle tracking in placet. The 2D-Oide effect is demonstrated to be important, as it increases by 17% the contribution to the beam size. Further insight into the aberrations induced by the synchrotron radiation opens the possibility to partially correct the 2D-Oide effect with octupole magnets. A beam size reduction of 4% is achieved in the simplest configuration, using a single octupole.

  10. Anesthesia for pediatric external beam radiation therapy

    International Nuclear Information System (INIS)

    Background: For very young patients, anesthesia is often required for radiotherapy. This results in multiple exposures to anesthetic agents over a short period of time. We report a consecutive series of children anesthetized for external beam radiation therapy (EBRT). Methods: Five hundred twelve children ≤ 16 years old received EBRT from January 1983 to February 1996. Patient demographics, diagnosis, anesthesia techniques, monitoring, airway management, complications, and outcome were recorded for the patients requiring anesthesia. Results: One hundred twenty-three of the 512 children (24%) required 141 courses of EBRT with anesthesia. Anesthetized patients ranged in age from 20 days to 11 years (mean 2.6 ± 1.8 ). The frequency of a child receiving EBRT and requiring anesthesia by age cohort was: ≤ 1 year (96%), 1-2 years (93%), 2-3 years (80%), 3-4 years (51%), 4-5 years (36%), 5-6 years (13%), 6-7 years (11%), and 7-16 years (0.7%). Diagnoses included: primary CNS tumor (28%), retinoblastoma (27%), neuroblastoma (20%), acute leukemia (9%), rhabdomyosarcoma (6%), and Wilms' tumor (4%). Sixty-three percent of the patients had been exposed to chemotherapy prior to EBRT. The mean number of anesthesia sessions per patient was 22 ± 16. Seventy-eight percent of the treatment courses were once daily and 22% were twice daily. Anesthesia techniques included: short-acting barbiturate induction + inhalation maintenance (21%), inhalation only (20%), ketamine (19%), propofol only (12%), propofol induction + inhalation maintenance (7%), ketamine induction + inhalation maintenance (6%), ketamine or short-acting barbiturate induction + inhalation maintenance (6%). Monitoring techniques included: EKG (95%), O2 saturation (93%), fraction of inspired O2 (57%), and end-tidal CO2 (55%). Sixty-four percent of patients had central venous access. Eleven of the 74 children with a central line developed sepsis (15%): 6 of the 11 were anesthetized with propofol (55%), 4 with a short

  11. Beaming of Particles and Synchrotron Radiation in Relativistic Magnetic Reconnection

    Science.gov (United States)

    Kagan, Daniel; Nakar, Ehud; Piran, Tsvi

    2016-08-01

    Relativistic reconnection has been invoked as a mechanism for particle acceleration in numerous astrophysical systems. According to idealized analytical models, reconnection produces a bulk relativistic outflow emerging from the reconnection sites (X-points). The resulting radiation is therefore highly beamed. Using two-dimensional particle-in-cell simulations, we investigate particle and radiation beaming, finding a very different picture. Instead of having a relativistic average bulk motion with an isotropic electron velocity distribution in its rest frame, we find that the bulk motion of the particles in X-points is similar to their Lorentz factor γ, and the particles are beamed within ˜ 5/γ . On the way from the X-point to the magnetic islands, particles turn in the magnetic field, forming a fan confined to the current sheet. Once they reach the islands they isotropize after completing a full Larmor gyration and their radiation is no longer strongly beamed. The radiation pattern at a given frequency depends on where the corresponding emitting electrons radiate their energy. Lower-energy particles that cool slowly spend most of their time in the islands and their radiation is not highly beamed. Only particles that quickly cool at the edge of the X-points generate a highly beamed fan-like radiation pattern. The radiation emerging from these fast cooling particles is above the burn-off limit (˜100 MeV in the overall rest frame of the reconnecting plasma). This has significant implications for models of gamma-ray bursts and active galactic nuclei that invoke beaming in that frame at much lower energies.

  12. Interstitial implantation as a radiation boost for high risk patients treated with breast conservation therapy

    International Nuclear Information System (INIS)

    Purpose: As part of a prospective institutional protocol for breast conservation treatment which employed aggressive therapy to the tumor-bearing quadrant, interstitial implantation was the preferred method of boost after 50.4 Gy whole breast irradiation for 'high risk' patients with tumor margins ≤ 2 mm. An analysis of clinical outcomes with respect to local tumor control and breast cosmesis was performed. Patients and Methods: From 1982-1994, 128 patients received an implant boost and a comparison data base was drawn from a total experience of 501 treated breasts. The median age of the implanted patients was 51 yrs and the median follow-up was 75 mos (range 10-150 mos). The implant target volume was determined by clinical assessment of post-operative induration and pre- and post-excisional mammograms. All implants were constructed in accordance with a pre-planning algorithm designed to maximize dose homogeniety within a prescription isodose goal of 50 cGy/hr. Local control and cosmetic outcome were evaluated with respect to extent of tumor, histopathology, margin status, extent of surgery, and systemic adjuvant therapy. Implant quality was assessed using four calculated parameters: strand separation product (SSP), planar separation product (PSP), global separation product (GSP), and dose homogeneity index (DHI). The mean implant volume was 47.9 ± 20.2 cc, the mean prescribed dose rate was 46.2 ± 8.5 cGy/hr and the mean total implant dose was 1993.8 ± 151.0 cGy. The final excision margin was positive, >0<1 mm, 1-2 mm, and indeterminate in 50%, 19%, 21%, and 15%, respectively. Results: Cosmetic outcome was good/excellent in 91% of patients which was not statistically different from non-implant patients. Logistic regression analysis revealed that re-excision, elevated SSP, and decreased DHI were associated with adverse cosmesis. There were 10 local failures in the implanted patients (4 within the prescribed isodose volume, 5 at the periphery and 1 elsewhere in

  13. Apparatus for defining a beam of ionizing radiation

    International Nuclear Information System (INIS)

    Novel apparatus for defining a beam of ionizing radiation in the course of radiotherapy treatment is described in detail. The particular case of electron irradiation of the patient is discussed. The apparatus consists of an adjustable primary collimator which produces a cone of ionizing radiation, an attachment holder adjacent to the primary collimator and a detachable radiation applicator. The attachment holder may be removed when irradiation with X-rays is desired. (U.K.)

  14. Device for limiting a beam of high-energy radiation

    International Nuclear Information System (INIS)

    In order to account for the varying scattered radiation and to optimize the image quality of the radiograph to be produced by the X-radiation, the radiation exit opening can be altered by means of trapezoidal shutter elements. For this purpose the shutter elements are designed swinging and, at their edges, gear tooth-like, thus forming a pyramidal shutter mechanism whose inclinitation with respect to the beam axis is adjustable (collimator). (RW)

  15. Optimal schedules of fractionated radiation therapy by way of the greedy principle: biologically-based adaptive boosting

    International Nuclear Information System (INIS)

    We revisit a long-standing problem of optimization of fractionated radiotherapy and solve it in considerable generality under the following three assumptions only: (1) repopulation of clonogenic cancer cells between radiation exposures follows linear birth-and-death Markov process; (2) clonogenic cancer cells do not interact with each other; and (3) the dose response function s(D) is decreasing and logarithmically concave. Optimal schedules of fractionated radiation identified in this work can be described by the following ‘greedy’ principle: give the maximum possible dose as soon as possible. This means that upper bounds on the total dose and the dose per fraction reflecting limitations on the damage to normal tissue, along with a lower bound on the time between successive fractions of radiation, determine the optimal radiation schedules completely. Results of this work lead to a new paradigm of dose delivery which we term optimal biologically-based adaptive boosting (OBBAB). It amounts to (a) subdividing the target into regions that are homogeneous with respect to the maximum total dose and maximum dose per fraction allowed by the anatomy and biological properties of the normal tissue within (or adjacent to) the region in question and (b) treating each region with an individual optimal schedule determined by these constraints. The fact that different regions may be treated to different total dose and dose per fraction mean that the number of fractions may also vary between regions. Numerical evidence suggests that OBBAB produces significantly larger tumor control probability than the corresponding conventional treatments. (paper)

  16. Beam diagnostics using transition radiation produced by a 100 Mev electron beam

    International Nuclear Information System (INIS)

    We report on several experiments using the optical transition radiation (OTR) produced by a 100 MeV electron beam. In using a sensitive video camera coupled with a digital image processing system an accurate and simple beam profile monitor has been devised. In measuring with a photo-multiplier the radiation emitted in a small solid angle around the direction of the OTR emission, a signal very sensitive to beam energy variations has been obtained. These experiments have been carried out on the Saclay ALS linac

  17. Study on external beam radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Mi Sook; Yoo, Seoung Yul; Yoo, Hyung Jun; Ji, Young Hoon; Lee, Dong Han; Lee, Dong Hoon; Choi, Mun Sik; Yoo, Dae Heon; Lee, Hyo Nam; Kim, Kyeoung Jung

    1999-04-01

    To develop the therapy technique which promote accuracy and convenience in external radiation therapy, to obtain the development of clinical treatment methods for the global competition. The contents of the R and D were 1. structure, process and outcome analysis in radiation therapy department. 2. Development of multimodality treatment in radiation therapy 3. Development of computation using networking techniques 4. Development of quality assurance (QA) system in radiation therapy 5. Development of radiotherapy tools 6. Development of intraoperative radiation therapy (IORT) tools. The results of the R and D were 1. completion of survey and analysis about Korea radiation therapy status 2. Performing QA analysis about ICR on cervix cancer 3. Trial of multicenter randomized study on lung cancers 4. Setting up inter-departmental LAN using MS NT server and Notes program 5. Development of ionization chamber and dose-rate meter for QA in linear accelerator 6. Development on optimized radiation distribution algorithm for multiple slice 7. Implementation on 3 dimensional volume surface algorithm and 8. Implementation on adaptor and cone for IORT.

  18. Study on external beam radiation therapy

    International Nuclear Information System (INIS)

    To develop the therapy technique which promote accuracy and convenience in external radiation therapy, to obtain the development of clinical treatment methods for the global competition. The contents of the R and D were 1. structure, process and outcome analysis in radiation therapy department. 2. Development of multimodality treatment in radiation therapy 3. Development of computation using networking techniques 4. Development of quality assurance (QA) system in radiation therapy 5. Development of radiotherapy tools 6. Development of intraoperative radiation therapy (IORT) tools. The results of the R and D were 1. completion of survey and analysis about Korea radiation therapy status 2. Performing QA analysis about ICR on cervix cancer 3. Trial of multicenter randomized study on lung cancers 4. Setting up inter-departmental LAN using MS NT server and Notes program 5. Development of ionization chamber and dose-rate meter for QA in linear accelerator 6. Development on optimized radiation distribution algorithm for multiple slice 7. Implementation on 3 dimensional volume surface algorithm and 8. Implementation on adaptor and cone for IORT

  19. Collisionless Beam-radiation Processes In The Laboratory And Astrophysics

    CERN Document Server

    Schmekel, B S

    2005-01-01

    Plasma instabilities can be encountered in many branches of physics. This work focuses on relativistic plasmas with applications in theoretical astrophysics and particle accelerator physics. Even though these fields seem to be unrelated the underlying plasma physics processes are often very similar. Two plasma instabilities - the beam-beam instability and the coherent synchrotron radiation instability - are analyzed. The former severely limits the achievable luminosity in storage rings and is related to the two- stream instability which has been proposed as a candidate for the radiation mechanism of radio pulsars. The main emphasis is on coherent synchrotron radiation which can lead to prohibitive energy losses in bunch compressors. Coherent synchrotron radiation also makes up the intense emission of radio waves by pulsars. Simple models based on the linearized Vlasov equation and relativistic magnetohydrodynamics which allow to compute detailed spectra of the emitted radiation are developed.

  20. Collisionless Beam-Radiation Processes in the Laboratory and Astrophysics

    CERN Document Server

    Schmekel, Bjoern S

    2009-01-01

    Plasma instabilities can be encountered in many branches of physics. This work focuses on relativistic plasmas with applications in theoretical astrophysics and particle accelerator physics. Even though these fields seem to be unrelated the underlying plasma physics processes are often very similar. Two plasma instabilities - the beam-beam instability and the coherent synchrotron radiation instability - are analyzed. The former severely limits the achievable luminosity in storage rings and is related to the two-stream instability which has been proposed as a candidate for the radiation mechanism of radio pulsars. The main emphasis is on coherent synchrotron radiation which can lead to prohibitive energy losses in bunch compressors. Coherent synchrotron radiation also makes up the intense emission of radio waves by pulsars. Simple models based on the linearized Vlasov equation and relativistic magnetohydrodynamics which allow to compute detailed spectra of the emitted radiation are developed.

  1. Monte Carlo dose verification of prostate patients treated with simultaneous integrated boost intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    To evaluate the dosimetric differences between Superposition/Convolution (SC) and Monte Carlo (MC) calculated dose distributions for simultaneous integrated boost (SIB) prostate cancer intensity modulated radiotherapy (IMRT) compared to experimental (film) measurements and the implications for clinical treatments. Twenty-two prostate patients treated with an in-house SIB-IMRT protocol were selected. SC-based plans used for treatment were re-evaluated with EGS4-based MC calculations for treatment verification. Accuracy was evaluated with-respect-to film-based dosimetry. Comparisons used gamma (γ)-index, distance-to-agreement (DTA), and superimposed dose distributions. The treatment plans were also compared based on dose-volume indices and 3-D γ index for targets and critical structures. Flat-phantom comparisons demonstrated that the MC algorithm predicted measurements better than the SC algorithm. The average PTVprostate D98 agreement between SC and MC was 1.2% ± 1.1. For rectum, the average differences in SC and MC calculated D50 ranged from -3.6% to 3.4%. For small bowel, there were up to 30.2% ± 40.7 (range: 0.2%, 115%) differences between SC and MC calculated average D50 index. For femurs, the differences in average D50 reached up to 8.6% ± 3.6 (range: 1.2%, 14.5%). For PTVprostate and PTVnodes, the average gamma scores were >95.0%. MC agrees better with film measurements than SC. Although, on average, SC-calculated doses agreed with MC calculations within the targets within 2%, there were deviations up to 5% for some patient's treatment plans. For some patients, the magnitude of such deviations might decrease the intended target dose levels that are required for the treatment protocol, placing the patients in different dose levels that do not satisfy the protocol dose requirements

  2. Power Beaming Leakage Radiation as a SETI Observable

    Science.gov (United States)

    Benford, James N.; Benford, Dominic J.

    2016-07-01

    The most observable leakage radiation from an advanced civilization may well be from the use of power beaming to transfer energy and accelerate spacecraft. Applications suggested for power beaming involve launching spacecraft to orbit, raising satellites to a higher orbit, and interplanetary concepts involving space-to-space transfers of cargo or passengers. We also quantify beam-driven launch to the outer solar system, interstellar precursors, and ultimately starships. We estimate the principal observable parameters of power beaming leakage. Extraterrestrial civilizations would know their power beams could be observed, and so could put a message on the power beam and broadcast it for our receipt at little additional energy or cost. By observing leakage from power beams we may find a message embedded on the beam. Recent observations of the anomalous star KIC 8462852 by the Allen Telescope Array (ATA) set some limits on extraterrestrial power beaming in that system. We show that most power beaming applications commensurate with those suggested for our solar system would be detectable if using the frequency range monitored by the ATA, and so the lack of detection is a meaningful, if modest, constraint on extraterrestrial power beaming in that system. Until more extensive observations are made, the limited observation time and frequency coverage are not sufficiently broad in frequency and duration to produce firm conclusions. Such beams would be visible over large interstellar distances. This implies a new approach to the SETI search: instead of focusing on narrowband beacon transmissions generated by another civilization, look for more powerful beams with much wider bandwidth. This requires a new approach for their discovery by telescopes on Earth. Further studies of power beaming applications should be performed, potentially broadening the parameter space of the observable features that we have discussed here.

  3. Synchrotron radiation damping, intrabeam scattering and beam-beam simulations for HE-LHC

    CERN Document Server

    Valishev, A

    2011-01-01

    The proposed High-Energy LHC project presents an unusual combination of strong synchrotron radiation (SR) damping and intrabeam scattering (IBS), which is not seen in present-day hadron colliders. The subject of investigation reported in this paper was the simulation of beam-beam effect for the HE-LHC parameters. Parameters of SR and IBS are calculated, and the luminosity evolution is simulated in the absence of beambeam interaction. Then, a weak-strong numerical simulation is used to predict the effect of beam-beam interaction on particle losses and emittance evolution.

  4. Intensity Modulated Proton Beam Radiation for Brachytherapy in Patients With Cervical Carcinoma

    International Nuclear Information System (INIS)

    Purpose: To evaluate intensity modulated proton therapy (IMPT) in patients with cervical cancer in terms of coverage, conformity, and dose–volume histogram (DVH) parameters correlated with recommendations from magnetic resonance imaging (MRI)-guided brachytherapy. Methods and Materials: Eleven patients with histologically proven cervical cancer underwent primary chemoradiation for the pelvic lymph nodes, the uterus, the cervix, and the parametric region, with a symmetric margin of 1 cm. The prescription was for 50.4 Gy, with 1.8 Gy per fraction. The prescribed dose to the parametria was 2.12 Gy up to 59.36 Gy in 28 fractions as a simultaneous boost. For several reasons, the patients were unable to undergo brachytherapy. As an alternative, IMPT was planned with 5 fractions of 6 Gy to the cervix, including the macroscopic tumor with an MRI-guided target definition, with an isotropic margin of 5 mm for planning target volume (PTV) definition. Groupe-Europeen de Curietherapie and European society for Radiotherapy and Oncology (GEC-ESTRO) criteria were used for DVH evaluation. Reference comparison plans were optimized for volumetric modulated rapid arc (VMAT) therapy with the RapidArc (RA). Results: The dose to the high-risk volume was calculated with α/β = 10 with 89.6 Gy. For IMPT, the clinical target volume showed a mean dose of 38.2 ± 5.0 Gy (35.0 ±1.8 Gy for RA). The D98% was 31.9 ± 2.6 Gy (RA: 30.8 ± 1.0 Gy). With regard to the organs at risk, the 2Gy Equivalent Dose (EQD2) (α/β = 3) to 2 cm3 of the rectal wall, sigmoid wall, and bladder wall was 62.2 ± 6.4 Gy, 57.8 ± 6.1 Gy, and 80.6 ± 8.7 Gy (for RA: 75.3 ± 6.1 Gy, 66.9 ± 6.9 Gy, and 89.0 ± 7.2 Gy, respectively). For the IMPT boost plans in combination with external beam radiation therapy, all DVH parameters correlated with <5% risk for grades 2 to 4 late gastrointestinal and genitourinary toxicity. Conclusion: In patients who are not eligible for brachytherapy, IMPT as a boost technique

  5. Intensity Modulated Proton Beam Radiation for Brachytherapy in Patients With Cervical Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Clivio, Alessandro [Oncology Institute of Southern Switzerland, Bellinzona (Switzerland); Kluge, Anne [Department of Radiation Oncology, Charité University Hospital, Berlin (Germany); Cozzi, Luca, E-mail: lucozzi@iosi.ch [Oncology Institute of Southern Switzerland, Bellinzona (Switzerland); Köhler, Christhardt [Department of Gynecology, Charité University Hospital, Berlin (Germany); Neumann, Oliver [Department of Radiation Oncology, Charité University Hospital, Berlin (Germany); Vanetti, Eugenio [Oncology Institute of Southern Switzerland, Bellinzona (Switzerland); Wlodarczyk, Waldemar; Marnitz, Simone [Department of Radiation Oncology, Charité University Hospital, Berlin (Germany)

    2013-12-01

    Purpose: To evaluate intensity modulated proton therapy (IMPT) in patients with cervical cancer in terms of coverage, conformity, and dose–volume histogram (DVH) parameters correlated with recommendations from magnetic resonance imaging (MRI)-guided brachytherapy. Methods and Materials: Eleven patients with histologically proven cervical cancer underwent primary chemoradiation for the pelvic lymph nodes, the uterus, the cervix, and the parametric region, with a symmetric margin of 1 cm. The prescription was for 50.4 Gy, with 1.8 Gy per fraction. The prescribed dose to the parametria was 2.12 Gy up to 59.36 Gy in 28 fractions as a simultaneous boost. For several reasons, the patients were unable to undergo brachytherapy. As an alternative, IMPT was planned with 5 fractions of 6 Gy to the cervix, including the macroscopic tumor with an MRI-guided target definition, with an isotropic margin of 5 mm for planning target volume (PTV) definition. Groupe-Europeen de Curietherapie and European society for Radiotherapy and Oncology (GEC-ESTRO) criteria were used for DVH evaluation. Reference comparison plans were optimized for volumetric modulated rapid arc (VMAT) therapy with the RapidArc (RA). Results: The dose to the high-risk volume was calculated with α/β = 10 with 89.6 Gy. For IMPT, the clinical target volume showed a mean dose of 38.2 ± 5.0 Gy (35.0 ±1.8 Gy for RA). The D{sub 98%} was 31.9 ± 2.6 Gy (RA: 30.8 ± 1.0 Gy). With regard to the organs at risk, the 2Gy Equivalent Dose (EQD2) (α/β = 3) to 2 cm{sup 3} of the rectal wall, sigmoid wall, and bladder wall was 62.2 ± 6.4 Gy, 57.8 ± 6.1 Gy, and 80.6 ± 8.7 Gy (for RA: 75.3 ± 6.1 Gy, 66.9 ± 6.9 Gy, and 89.0 ± 7.2 Gy, respectively). For the IMPT boost plans in combination with external beam radiation therapy, all DVH parameters correlated with <5% risk for grades 2 to 4 late gastrointestinal and genitourinary toxicity. Conclusion: In patients who are not eligible for brachytherapy, IMPT as a boost

  6. A boost for KAON

    International Nuclear Information System (INIS)

    Earlier this year, a report by a specially-formed subcommittee of the US Nuclear Science Advisory Committee gave an important boost to the proposal to build a high intensity particle beam 'factory' at the Canadian TRIUMF laboratory in Vancouver. (orig./HSI).

  7. Coherent X-ray Cherenkov radiation produced by microbunched beams

    International Nuclear Information System (INIS)

    Analytical and numerical results on the coherent X-ray Cherenkov radiation (CXCR) produced by microbunched beams in the region near the K-, L-edges of materials are obtained. The results show that CXCR can serve as a suitable mechanism for production intense beams of photons in the 'water window' region as well as for studying the important microbunching process at FLASH TESLA, LCLS and other FELs.

  8. Influence of boost technique (external beam radiotherapy or brachytherapy) on the outcome of patients with carcinoma of the base of the tongue

    International Nuclear Information System (INIS)

    We reviewed 90 patients with squamous cell carcinoma of the base of the tongue. Fifty-three patients were treated with external beam radiotherapy alone (3 T1, 11 T2, 21 T3, and 18 T4 tumors) and thirty-seven patients were treated with external beam radiotherapy plus brachytherapy boost (4 T1, 15 T2, 11 T3, and 7 T4 tumors). For patients with T1, T2 and T3 primaries, the actuarial 3-year local relapse-free survival was 42% following external beam radiotherapy alone and 67% following external beam radiotherapy plus brachytherapy (p<0.05). The actuarial 3-year cause specific survival for these T-stages was 37% for patients treated with external beam radiotherapy alone and 53% for patients treated with external beam radiotherapy plus brachytherapy (p=0.1). In the Cox multivariate analyses restricted patients with T1, T2 and T3 staged tumors, treatment modality was the only predictor for local control but no influence on specific survival was found. The trend towards significant differences in specific survival found in the univariate comparison of both treatment modalities was probably due to the significantly higher number of N-positive patients treated with external beam radiotherapy alone. When all stages were included in the Cox analysis, low hemoglobin level, invasion of deep muscle, number of palpable nodes, and history of weight loss significantly influenced the outcome. Soft tissue necrosis occurred more frequently in patients treated with external beam radiotherapy plus brachytherapy (33% vs. 10%, p=0.52). (orig.)

  9. Responses of diode detectors to radiation beams from teletherapy machines

    International Nuclear Information System (INIS)

    Responses of diode detectors to radiation beams from teletherapy machines. It has been carried out responses to two sets of diode detector by using the beams of teletherapy Co-60 and medical linear accelerator. Each set of consist of 8 diode detectors was irradiated by using gamma beams from teletherapy Co-60 machines and 6 MV and 10 MV foron beams from medical linear accelerator and 6.9.12.16. and 20 MeV electron beams from medical linear accelerator. The detectors were positioned on the phantom circularly and radially and electronic equilibrium condition for all type and energy beams. It was found that every detectors had own individual response and it is not to be uniformity, since the fluctuation in between 16.6 % to 30.9 %. All detectors responses are linear to gamma and foron beams, and also for energy above 6 MeV for electron beams. Nonlinearity response occurs for 6 MeV electron beam, it is probably from the assumption of electronic equilibrium

  10. Radiation degradation of marine polysaccharides by low energy electron beam

    International Nuclear Information System (INIS)

    The radiation degradations of marine polysaccharides by both gamma Co-60 and electron beam irradiations are investigated. Polysaccharides and oligosaccharides can be produced by degradation of corresponding polysaccharides including marine polysaccharides such as alginates, chitin chitosan and carrageenan. The viscosity of alginate, chitosan and carrageenan solution decreases markedly with increase of the low energy electron beam irradiation time and the beam current. Furthermore, the viscosity is reduced sharply in short time for polysaccharide solution with low concentration, for instance carrageenan solution of 1%. (author)

  11. Spectral properties of Compton inverse radiation: Application of Compton beams

    CERN Document Server

    Bulyak, Eugene

    2013-01-01

    Compton inverse radiation emitted due to backscattering of laser pulses off the relativistic electrons possesses high spectral density and high energy of photons - in hard x-ray up to gamma-ray energies - because of short wavelength of laser radiation as compared with the classical electromagnetic devices such as undulators. In this report, the possibility of such radiation to monochromatization by means of collimation is studied. Two approaches have been considered for the description of the spectral-angular density of Compton radiation based on the classical field theory and on the quantum electrodynamics. As is shown, both descriptions produce similar total spectra. On the contrary, angular distribution of the radiation is different: the classical approach predicted a more narrow radiation cone. Also proposed and estimated is a method of the `electronic' monochromatization based on the electronic subtraction of the two images produced by the electron beams with slightly different energies. A `proof-of-prin...

  12. Radiation sterilization by 10 MeV electron beams

    International Nuclear Information System (INIS)

    Gamma-ray sterilization by 60Co source has been already popular in Japan. Many Kinds of medical plastic devices such as catheters, disposable syringes, dializers etc, has been irradiated at 60Co irradiation facilities instead of the conventional ethylene oxide fumigation method. On the other hand, improvement of the quality of electron accelerators has made it easier to take advantage of relatively high energy electrons which are profitable for radiation sterilization because of their high dose rate saving process hours and easiness of source handling and radiation control. So electron-beam sterilization is now under investigation in Japan and, partly, it will be practiced in the near future. Yet few data are available in the present situation. Especially for high energy electron beams near 10 MeV, more data are necessary for practical application of electron-beam sterilization. Therefore, in this study, sensitivity of Bacillus pumilus E601, the biological standard of radiation sterilization, was examined using 10 MeV electron beams from linear accelerator and sterility of the beams was also checked at each depth of plastic boards in order to get basic information for determination of sterility dose. Endospores from B. pumilus were dried on filter papers (Toyo No.1) and irradiated by 10 MeV electron beams of 60Co gamma-rays. The survival curves were shown in Fig. 1. The D values were obtained as 1.9 kGy ± 0.2 for electron beams and 1.7 kGy ± 0.1 for 60Co gamma-rays, both of which were similar. Electron beams could sterilize the endospores nearly uniformly till 3 cm depth of plastic boards at 10 MeV (Fig. 2,3). This indicates a possibility to sterilize relatively bulky products such as dializers etc. (author)

  13. Online external beam radiation treatment simulator

    International Nuclear Information System (INIS)

    Radiation therapy is an effective and widely accepted form of treatment for many types of cancer that requires extensive computerized planning. Unfortunately, current treatment planning systems have limited or no visual aid that combines patient volumetric models extracted from patient-specific CT data with the treatment device geometry in a 3D interactive simulation. We illustrate the potential of 3D simulation in radiation therapy with a web-based interactive system that combines novel standards and technologies. We discuss related research efforts in this area and present in detail several components of the simulator. An objective assessment of the accuracy of the simulator and a usability study prove the potential of such a system for simulation and training. (orig.)

  14. Calculating the background radiation in the vicinity of the beam catchers of the ELBE radiation source

    International Nuclear Information System (INIS)

    The ELBE radiation sources comprises beam catchers in the experimenting sites which absorb the primary electron beam as well as the generated secondary radiation. The beam catcher consists of an ultrapure graphite absorber enclosed in a water-cooled stainless steel shell. Background radiation is shielded by iron, lead and heavy concrete. The beam parameters and the position of the beam catchers differ between experimenting sites. In order to determine the dose dependence of photon and neutron fluence and the dose equivalent at the cooling shell of the beam catcher, simulations were carried out using the FLUKA code. Radiation energies of 20 MeV and 50 MeV and electron fluxes of 1 mA were considered. The spatial and energetic distributions of the dose rate equivalent provide a basis for dimensioning of the radiation shields. The calculated distributions of the energy dose rate in the beam catcher serve as a basis for assessing thermal loads on materials and for designing the cooling system. (orig.)

  15. Electron Beam Instrumentation Techniques Using Coherent Radiation

    Science.gov (United States)

    Wang, D. X.

    1997-05-01

    In recent years, there has been increasing interest in short electron bunches for different applications such as short wavelength FELs, linear colliders, advanced accelerators such as laser or plasma wakefield accelerators, and Compton backscattering X-ray sources. A short bunch length is needed to meet various requirements such as high peak current, low momentum spread, high luminosity, small ratio of bunch length to plasma wavelength, or accurate timing. Meanwhile, much progress has been made on photoinjectors and different magnetic and RF bunching schemes to produce very short bunches. Measurement of those short bunches becomes essential to develop, characterize, and operate such demanding machines. Conventionally, bunch duration of short electron bunches is measured by transverse RF deflecting cavities or streak camera. With such devices it becomes very challenging to measure bunch length down to a few hundred femtoseconds. Many frequency domain techniques have been recently developed, based on a relation between bunch profile and coherent radiation spectrum. These techniques provide excellent performance for short bunches. In this paper, coherent radiation and its applications to bunch length measurement will be discussed. A strategy for bunch length control at Jefferson Lab will be presented, which includes a noninvasive coherent synchrotron radiation (CSR) monitor, a zero-phasing technique used to calibrate the CSR detector, and phase transfer measurement used to correct RF phase drifts.

  16. Simultaneous integrated boost with intensity modulated radiation therapy in brain oligometastases: A feasible technique for developing countries

    Directory of Open Access Journals (Sweden)

    Vivek Tiwari

    2015-01-01

    Full Text Available Introduction: To analyze the pattern of brain metastasis (BM, and to use intensity modulated radiation therapy (IMRT for target dose escalation in cases with ≤3 metastatic lesions (oligometastases. Materials and Methods: Thirty-two consecutive cases of BM treated during September 2009 to August 2012 were analyzed retrospectively. Results: The study comprised 13 males (40.62% and 19 females (59.37%. Thirteen (40% patients presented with disseminated intracranial metastases, while 19 (60% had ≤3 foci. In 25 cases (78%, the primary was located either in the breast (14 cases or lung (11 cases. The 13 patients with disseminated intracranial metastases received whole brain radiation therapy to a dose of 30 Gy/10-12 daily fractions (Group A while the 19 cases with ≤3 lesions received an additional dose of 6-10 Gy to gross lesions using a simultaneous integrated boost (SIB with IMRT thus receiving a total dose of 36-40 Gy/12-15 fractions (Group B. Overall survival (OS for the breast primary was 6.3 and lung primary was 5.3 months, respectively. The mean OS for breast cases in Group B was higher (9.5 months as compared to Group A cases (1.9 months and was statistically significant (P = 0.0056. Similarly, primary lung cancer cases in Group B showed a mean OS of 8.75 months versus 2.6 months for Group A cases (P = 0.213. Conclusions: IMRT is a safe and effective technique in cases with oligometastases for dose escalation in the form of SIB.

  17. Long-term Outcomes in Treatment of Invasive Bladder Cancer With Concomitant Boost and Accelerated Hyperfractionated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Canyilmaz, Emine, E-mail: dremocan@yahoo.com [Department of Radiation Oncology, Karadeniz Technical University, Trabzon (Turkey); Yavuz, Melek Nur [Department of Radiation Oncology, Akdeniz University, Antalya (Turkey); Serdar, Lasif [Department of Radiation Oncology, Karadeniz Technical University, Trabzon (Turkey); Uslu, Gonca Hanedan; Zengin, Ahmet Yasar [Department of Radiation Oncology, Kanuni Research and Education Hospital, Trabzon (Turkey); Aynaci, Ozlem; Haciislamoglu, Emel; Bahat, Zumrut; Yoney, Adnan [Department of Radiation Oncology, Karadeniz Technical University, Trabzon (Turkey)

    2014-11-01

    Purpose: The aim of this study was to evaluate the long-term clinical efficacy and toxicity of concomitant boost and accelerated hyperfractionated radiation therapy (CBAHRT) in patients with invasive bladder cancer. Methods and Materials: Between October 1997 and September 2012, 334 patients with diagnoses of invasive bladder cancer were selected. These patients received CBAHRT as a bladder-conserving approach. The treatment consisted of a dose of 45 Gy/1.8 Gy to the whole pelvis with a daily concomitant boost of 1.5 Gy to the tumor. Total dose was 67.5 Gy in 5 weeks. A total of 32 patients (10.3%) had a diagnosis of stage T1, 202 (64.3%) were at stage T2, 46 (14.6%) were at stage T3a, 22 (7%) were at stage T3b, and 12 (3.8%) were at stage T4a. Results: The follow-up period was 33.1 months (range, 4.3-223.3 months). Grade 3 late intestinal toxicity was observed in 9 patients (2.9%), whereas grade 3 late urinary toxicity was observed in 8 patients (2.5%). The median overall survival (OS) was 26.3 months (95% confidence interval [CI]: 21.4-31.2). The 5-, 10, and 15-year OS rates were 32.1% (standard error [SE], ± 0.027), 17.9% (SE, ± 0.025) and 12.5% (SE, ± 0.028), respectively. The median cause-specific survival (CSS) was 42.1 months (95% CI: 28.7-55.5). The 5-, 10-, and 15-year CSS rates were 43.2% (SE, ± 0.03), 30.3% (SE, ± 0.03), and 28% (SE, ± 0.04), respectively. The median relapse-free survival (RFS) was 111.8 months (95% CI: 99.6-124). The 5-, 10-, and 15-year RFS rates were 61.9% (SE, ± 0.03), 57.6% (SE, ± 0.04), and 48.2% (SE, ± 0.07), respectively. Conclusions: The CBAHRT technique demonstrated acceptable toxicity and local control rates in patients with invasive bladder cancer, and this therapy facilitated bladder conservation. In selected patients, the CBAHRT technique is a practical alternative treatment option with acceptable 5-, 10-, and 15-year results in patients undergoing cystectomy as well as concurrent chemoradiation therapy.

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

    OpenAIRE

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

    2014-01-01

    The aim of the study was to report the clinical results in patients with high-risk prostate cancer treated with pelvic intensity-modulated radiation therapy (IMRT) and simultaneous integrated boost (SIB) to the prostate area. A total of 110 patients entered our study, 37 patients presented with localized prostate cancer and radiological evidence of node metastases or ≥15% estimated risk of lymph node (LN) involvement, while 73 patients underwent postoperative adjuvant or salvage irradiation f...

  19. Electron beam radiation of resin luting agents - a cytotoxic evaluation

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate and compare the cytotoxicity of three resin luting agents rely x luting cement, rely x luting 2 cement, and clearfil SA luting agent on human dental pulp cells before and after electron beam irradiation. Growth and maintenance of cell cultures of human pulp cells was done in Dulbecco's modified Eagle's Medium (DMEM). The test samples were divided into two categories based on radiation exposure, irradiated category and non-radiated category. Samples in Irradiated category were exposed to electron beam radiation after dose standardisation (Microtron, Electron Beam Accelerator, Microtron Centre, Mangalore University). The dose of radiation used was 200 Gy. Two subgroups of radiated category were made. In 1st sub-group (containing 18 samples), all the 3 luting cements will be placed in sterile packets and irradiated without mixing the two components. In 2nd sub-group (containing 18 samples), all the 3 luting cements will be mixed separately, placed in sterile packets and exposed to electron-beam radiations. Samples in non radiated category were also made 2 groups. In 1st sub-group (containing 18 samples), all the 3 luting cements will be placed in sterile teflon moulds and kept in a humid chamber at 37℃ without mixing the two components. In 2nd sub-group (containing 18 samples), all the 3 the luting cements will be mixed separately, placed in sterile teflon moulds and kept in a humid chamber at 37℃. All the samples were subjected to MTT assay and spectrophotometric analysis and their cytotoxicity was assessed. (author)

  20. Short Electron Beam Bunch Characterization Through Measurement of Terahertz Radiation

    CERN Document Server

    Zhang, Shukui; Douglas, David; Shinn, Michelle D; Williams, Gwyn

    2004-01-01

    Characterization of the electron beam bunch length of the upgrade FEL at Jefferson Lab was performed by analyzing the FTIR spectra of the coherent terahertz pulses. The results are compared with autocorrelation from a scanning polarization autocorrelator that measures the optical transition radiation. The limitations of the different methods to such a characterization are presented in this paper.

  1. Prospects for radiation-beam treatment of materials for atomics

    International Nuclear Information System (INIS)

    A consideration is given to various types of radiation-beam technology (ion, plasma, ion-plasma treatments, irradiation with concentrated fluxes of energy) as well as to prospects of their use for optimization of structural and phase states of reactor materials and for surface finishing. The results of corrosion tests and structural studies are presented for fuel tubes of Eh110 and Eh635 zirconium alloys and steels ChS-68, EhJ847, EhP172, EhP450, EhP753 before and after radiation-beam treatments. It is revealed that corrosion resistance and wear resistance are enhanced due to structural changes in a subsurface layer. The advantages of radiation-beam technology are noted to be ecological safety, low power consumption, high controllability and predictability of the results of action, a possibility to vary essentially the element composition and the phase state of a surface layer, as well as to form a specified surface relief. The radiation-beam technology is shown to be promising for treatment of nuclear reactor core components operating under severe conditions

  2. A phase-space beam position monitor for synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Samadi, Nazanin, E-mail: nazanin.samadi@usask.ca [University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK (Canada); Bassey, Bassey; Martinson, Mercedes [University of Saskatchewan, 116 Science Place, Saskatoon, SK (Canada); Belev, George; Dallin, Les; Jong, Mark de [Canadian Light Source, 44 Innovation Boulevard, Saskatoon, SK (Canada); Chapman, Dean [University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK (Canada)

    2015-06-25

    A system has been developed to measure the vertical position and angle of the electron beam at a single location from a synchrotron source. The system uses a monochromator tuned to the absorption edge of a contrast material and has a sensitivity comparable with other beam position monitors. The stability of the photon beam position on synchrotron beamlines is critical for most if not all synchrotron radiation experiments. The position of the beam at the experiment or optical element location is set by the position and angle of the electron beam source as it traverses the magnetic field of the bend-magnet or insertion device. Thus an ideal photon beam monitor would be able to simultaneously measure the photon beam’s position and angle, and thus infer the electron beam’s position in phase space. X-ray diffraction is commonly used to prepare monochromatic beams on X-ray beamlines usually in the form of a double-crystal monochromator. Diffraction couples the photon wavelength or energy to the incident angle on the lattice planes within the crystal. The beam from such a monochromator will contain a spread of energies due to the vertical divergence of the photon beam from the source. This range of energies can easily cover the absorption edge of a filter element such as iodine at 33.17 keV. A vertical profile measurement of the photon beam footprint with and without the filter can be used to determine the vertical centroid position and angle of the photon beam. In the measurements described here an imaging detector is used to measure these vertical profiles with an iodine filter that horizontally covers part of the monochromatic beam. The goal was to investigate the use of a combined monochromator, filter and detector as a phase-space beam position monitor. The system was tested for sensitivity to position and angle under a number of synchrotron operating conditions, such as normal operations and special operating modes where the photon beam is intentionally altered

  3. Patient radiation doses for electron beam CT

    International Nuclear Information System (INIS)

    A Monte Carlo based computer model has been developed for electron beam computed tomography (EBCT) to calculate organ and effective doses in a humanoid hermaphrodite phantom. The program has been validated by comparison with experimental measurements of the CT dose index in standard head and body CT dose phantoms; agreement to better than 8% has been found. The robustness of the model has been established by varying the input parameters. The amount of energy deposited at the 12:00 position of the standard body CT dose phantom is most susceptible to rotation angle, whereas that in the central region is strongly influenced by the beam quality. The program has been used to investigate the changes in organ absorbed doses arising from partial and full rotation about supine and prone subjects. Superficial organs experience the largest changes in absorbed dose with a change in subject orientation and for partial rotation. Effective doses for typical clinical scan protocols have been calculated and compared with values obtained using existing dosimetry techniques based on full rotation. Calculations which make use of Monte Carlo conversion factors for the scanner that best matches the EBCT dosimetric characteristics consistently overestimate the effective dose in supine subjects by typically 20%, and underestimate the effective dose in prone subjects by typically 13%. These factors can therefore be used to correct values obtained in this way. Empirical dosimetric techniques based on the dose-length product yield errors as great as 77%. This is due to the sensitivity of the dose length product to individual scan lengths. The magnitude of these errors is reduced if empirical dosimetric techniques based on the average absorbed dose in the irradiated volume (CTDIvol) are used. Therefore conversion factors specific to EBCT have been calculated to convert the CTDIvol to an effective dose

  4. A study of radiation-hard detectors using proton beam

    International Nuclear Information System (INIS)

    We studied radiation damage effect of inorganic and organic scintillators developed in Korea by proton beam irradiation using the MC-50 Cyclotron facility in Atomic Cancer Hospital. After developing radiation hard detectors, it can be used for the proton beam flux and energy monitoring in a real time. We also perform a research on electronics and DAQ for such a device. The following is our major study : a development of liquid scintillator, a development of plastic scintillator, a study on liquid scintillator response, simulation study of liquid scintillator by proton beam interaction, detector irradiation at MC-50 Cyclotron facility and a study of response change, a development of electronics for proton flux monitoring and a feasibility study of low proton flux monitoring, initial study of inorganic scintillator by the proton beamtest

  5. Boosting the tumor bed from deep-seated tumors in early-stage breast cancer: A planning study between electron, photon, and proton beams

    International Nuclear Information System (INIS)

    Purpose: To assess the potential dosimetric advantages and drawbacks of photon beams (modulated or not), electron beams (EB), and protons as a boost for the tumor bed in deep-seated early-stage breast cancer. Material and methods: Planning CTs of 14 women with deep-seated tumors (i.e., ≥4 cm depth) were selected. The clinical target volume (CTV) was defined as the area of architectural distortion surrounded by surgical clips. The planning treatment volume (PTV) was the CTV plus 1 cm margin. A dose of 16 Gy in 2 Gy fractions was prescribed. Organs at risk (OARs) were heart, lungs, breasts, and a 5-mm thick skin segment on the breast surface. Dose-volume metrics were defined to quantify the quality of concurrent treatment plans assessing target coverage and sparing of OAR. The following treatment techniques were assessed: photon beams with either static 3D-conformal, dynamic arc (DCA), static gantry intensity-modulated beams (IMRT), or RapidArc (RA); a single conformal EB; and intensity-modulated proton beams (IMPT). The goal for this planning effort was to cover 100% of the CTV with ≥95% of the prescribed dose and to minimize the volume inside the CTV receiving >107% of the dose. Results: All techniques but DCA and EB achieved the planning objective for the CTV with an inhomogeneity ranging from 2% to 11%. RA showed the best conformity, EB the worst. Contra-lateral breast and lung were spared by all techniques with mean doses 15Gy = 2.4%. Conclusions: Boosting the tumor bed in early-stage breast cancer with optimized photon or proton beams may be preferred to EB especially for deep-seated targets. The marked OAR (i.e., ipsi-lateral breast, lung, heart, and skin surface) dose-sparing effect may allow for a potential long-term toxicity risk reduction and better cosmesis. DCA or RA may also be considered alternative treatment options for patients eligible for accelerated partial breast irradiation trials.

  6. Measurement of microwave radiation from electron beam in the atmosphere

    Science.gov (United States)

    Ohta, I. S.; Akimune, H.; Fukushima, M.; Ikeda, D.; Inome, Y.; Matthews, J. N.; Ogio, S.; Sagawa, H.; Sako, T.; Shibata, T.; Yamamoto, T.

    2016-02-01

    We report the use of an electron light source (ELS) located at the Telescope Array Observatory in Utah, USA, to measure the isotropic microwave radiation from air showers. To simulate extensive air showers, the ELS emits an electron beam into the atmosphere and a parabola antenna system for the satellite communication is used to measure the microwave radiation from the electron beam. Based on this measurement, an upper limit on the intensity of a 12.5 GHz microwave radiation at 0.5 m from a 1018 eV air shower was estimated to be 3.96×10-16 W m-2 Hz-1 with a 95% confidence level.

  7. External Beam Radiation in Differentiated Thyroid Carcinoma

    Directory of Open Access Journals (Sweden)

    Salem Billan

    2016-01-01

    Full Text Available The treatment of differentiated thyroid carcinoma (DTC is surgery followed in some cases by adjuvant treatment, mostly with radioactive iodine (RAI. External beam radiotherapy (EBRT is less common and not a well-established treatment modality in DTC. The risk of recurrence depends on three major prognostic factors: extra-thyroid extension, patient’s age, and tumor with reduced iodine uptake. Increased risk for recurrence is a major factor in the decision whether to treat the patient with EBRT. Data about the use of EBRT in DTC are limited to small retrospective studies. Most series have demonstrated an increase in loco-regional control. The risk/benefit from giving EBRT requires careful patient selection. Different scoring systems have been proposed by different investigators and centers. The authors encourage clinicians treating DTC to become familiarized with those scoring systems and to use them in the management of different cases. The irradiated volume should include areas of risk for microscopic disease. Determining those areas in each case can be difficult and requires detailed knowledge of the surgery and pathological results, and also understanding of the disease-spreading pattern. Treatment with EBRT in DTC can be beneficial, and data support the use of EBRT in high-risk patients. Randomized controlled trials are needed for better confirmation of the role of EBRT.

  8. Beam loss and radiation effects in the SSC lattice elements

    International Nuclear Information System (INIS)

    The Superconducting Super Collider (SSC) is designed to be an advanced machine with relatively low beam loss-induced radiation levels. However, a fraction of the beam lost in the lattice due to pp-collisions at the interaction points, beam-gas scattering, bearn-halo scraping, various instabilities and errors will result in the irradiation of conventional and superconducting components of the accelerator and experimental apparatus. The level of the beam loss and its distribution along the machine structure has impact on all of the three crucial radiation effects at the SSC: quenching of the superconducting magnets, survivability of the accelerator and detectors components in the near-beam regions, and influence to the environment. This paper, based on the full-scale Monte Carlo simulation, will explore all major sources of beam loss in the Collider and measures to reduce the irradiation of the accelerator components. Basic parameters of the Super Collider accepted throughout this report are as follows: Proton energy E0 = 20 TeV, injection energy is 2 TeV, number of protons circulating in each of the collider rings is N = 1.3 x 1014, circumference is 87.12 km, the transverse normalized emittance var-epsilon N(σ) = 1 π mm-mrad, for the regular lattice (β = 305 m) the beam R.M.S. sizes are σ = 0.12 mm at 20 TEV and σ = 0.38 mm at the injection energy. The dipole length is 15.815 m with the effective field length of 15.165 m. The magnetic field map for B0 = 6.5999 T has been calculated with the POISSON program by Greg Snitchler. The turn angle of each dipole is α = 1.50027 mrad. The dipole aperture is 50 mm. The two beam pipe diameters are studied 33 and 40 mm. The operating temperature is T0 = 4.35 K

  9. Radiation Tolerance of Cryogenic Beam Loss Monitor Detectors

    CERN Document Server

    Kurfuerst, C; Bartosik, M; Dehning, B; Eisel, T; Sapinski, M; Eremin, V; Verbitskaya, E; Fabjan, C; Griesmayer, E

    2013-01-01

    At the triplet magnets, close to the interaction regions of the LHC, the current Beam Loss Monitoring system is sensitive to the particle showers resulting from the collision of the two beams. For the future, with beams of higher energy and intensity resulting in higher luminosity, distinguishing between these interaction products and possible quench-provoking beam losses from the primary proton beams will be challenging. Investigations are therefore underway to optimise the system by locating the beam loss detectors as close as possible to the superconducting coils of the triplet magnets. This means putting detectors inside the cold mass in superfluid helium at 1.9 K. Previous tests have shown that solid state diamond and silicon detectors as well as liquid helium ionisation chambers are promising candidates. This paper will address the final open question of their radiation resistance for 20 years of nominal LHC operation, by reporting on the results from high irradiation beam tests carried out at CERN in a...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-11-15

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

  11. Study of radiation detectors response in standard X, gamma and beta radiation standard beams

    International Nuclear Information System (INIS)

    The response of 76 Geiger-Mueller detectors, 4 semiconductor detectors and 34 ionization chambers were studied. Many of them were calibrated with gamma radiation beams (37Cs and 60Co), and some of them were tested in beta radiation (90Sr+9'0Y e 204Tl) and X radiation (N-60, N-80, N-100, N-150) beams. For all three types of radiation, the calibration factors of the instruments were obtained, and the energy and angular dependences were studied. For beta and gamma radiation, the angular dependence was studied for incident radiation angles of 0 deg and +- 45 deg. The curves of the response of the instruments were obtained over an angle interval of 0 deg to +- 90 deg, for gamma, beta and X radiations. The calibration factors obtained for beta radiation were compared to those obtained for gamma radiation. For gamma radiation, 24 of the 66 tested Geiger-Mueller detectors presented results for the energy dependence according to international recommendation of ISO 4037-2 and 56 were in accordance with the Brazilian ABNT 10011 recommendation. The ionization chambers and semiconductors were in accordance to national and international recommendations. All instruments showed angular dependence less than 40%. For beta radiation, the instruments showed unsatisfactory results for the energy dependence and angular dependence. For X radiation, the ionization chambers presented results for energy dependence according to the national recommendation, and the angular dependence was less than 40%. (author)

  12. Radiation effects of electron-beam metal depositions on IGFET's

    International Nuclear Information System (INIS)

    Electron-beam radiation effects on n-channel IGFET parameters were studied. This paper summarizes the resulting surface- and dielectric-radiation effects obtained with a series of experiments incorporating e-gun metal deposition on MOS, MNOS, and SNOS structures. The results are compared with those using resistance-heated metal deposition for various thin-film compositions between the metal and silicon surfaces. A comparison is also made with the effects of controlled direct e-beam irradiation of the structures. The efficiency of quartz and aluminum thin films over MNOS structures, in reducing e-gun radiation effects, is evaluated for double-level metallurgy structures. The effect of different thermal-annealing conditions for offsetting the radiation effects is determined. It is concluded that e-gun metallization causes large negative voltage shifts in MOS, MNOS, and SNOS devices. While MOS threshold shifts are fully ''annealable'', residual MNOS and SNOS V/sub T/ shifts are observed after an anneal of 3500/4500C. Thin films of quartz and aluminum over MOS and MNOS structures effectively reduce radiation effects. Other IGFET parameters are not substantially affected by e-gun radiation

  13. A comparative study of quality of life in patients with localized prostate cancer treated at a single institution: Stereotactic ablative radiotherapy or external beam + high dose rate brachytherapy boost

    International Nuclear Information System (INIS)

    Purpose: To compare the quality of life (QOL) in patients treated with stereotactic ablative radiation therapy (SABR) alone or high dose rate (HDR) brachytherapy + hypofractionated external beam radiotherapy (EBRT). Methods and materials: Patient self-reported QOL was prospectively measured among patients from two sequential phase 2 clinical trials: 1-SABR 35 Gy/5 fractions/5 weeks, 2–15 Gy HDR 1 fraction, followed by EBRT 37.5 Gy/15 fractions/3 weeks. The expanded prostate cancer index composite was assessed at baseline and q6 monthly up to 5 years. Urinary, bowel and sexual domains were analyzed. A minimally clinical important change (MCIC) was defined as 0.5*standard deviation of the baseline for each domain. Fisher exact test and general linear mixed model were used (p < 0.05). Results: 84 and 123 patients were treated on the SABR and HDR boost studies, with a median follow up of 51 and 61 months respectively. There was a significant difference in MCIC between treatments in the urinary function and bother (p < 0.0001), the bowel function (p = 0.0216) and the sexual function (p = 0.0419) and bother (p = 0.0290) domains in favor of the SABR group. Of patients who reported no problem with their sexual function at baseline, 7% and 23% respectively considered it to be a moderate to big problem on follow up (p = 0.0077). Conclusion: Patients treated with HDR-boost reported deterioration of QOL particularly in sexual domains in comparison with SABR

  14. Thin silicon strip detectors for beam monitoring in Micro-beam Radiation Therapy

    CERN Document Server

    Povoli, Marco; Bravin, Alberto; Cornelius, Iwan; Bräuer-Krisch, Elke; Fournier, Pauline; Hansen, Thor-Erik; Kok, Angela; Lerch, Michael; Monakhov, Edouard; Morse, John; Petasecca, Marco; Requardt, Herwig; Rosenfeld, Anatoly; Röhrich, Dieter; Sandaker, Heidi; Salomé, Murielle; Stugu, Bjarne

    2015-01-01

    Microbeam Radiation Therapy (MRT) is an emerging cancer treatment that is currently being developed at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. This technique uses a highly collimated and fractionated X-ray beam array with extremely high dose rate and very small divergence, to benefit from the dose-volume effect, thus sparing healthy tissue. In case of any beam anomalies and system malfunctions, special safety measures must be installed, such as an emergency safety shutter that requires continuous monitoring of the beam intensity profile. Within the 3DMiMic project, a novel silicon strip detector that can tackle the special features of MRT, such as the extremely high spatial resolution and dose rate, has been developed to be part of the safety shutter system. The first prototypes have been successfully fabricated, and experiments aimed to demonstrate their suitability for this unique application have been performed. Design, fabrication and the experimental results as well as any...

  15. The potential of proton beam radiation therapy in breast cancer

    International Nuclear Information System (INIS)

    A group of Swedish oncologists and hospital physicists have estimated the number of patients in Sweden suitable for proton beam therapy. The estimations have been based on current statistics of tumour incidence, number of patients potentially eligible for radiation treatment, scientific support from clinical trials and model dose planning studies and knowledge of the dose-response relations of different tumours and normal tissues. In primary breast cancer, it is estimated that about 300 of the annually 3,425 irradiated patients can potentially be candidates for proton beam therapy to reduce late toxicity, mainly from the heart and lungs

  16. Terahertz plasmonic laser radiating in an ultra-narrow beam

    CERN Document Server

    Wu, Chongzhao; Reno, John L; Kumar, Sushil

    2016-01-01

    Plasmonic lasers (spasers) generate coherent surface-plasmon-polaritons (SPPs) and could be realized at subwavelength dimensions in metallic cavities for applications in nanoscale optics. Plasmonic cavities are also utilized for terahertz quantum-cascade lasers (QCLs), which are the brightest available solid-state sources of terahertz radiation. A long standing challenge for spasers is their poor coupling to the far-field radiation. Unlike conventional lasers that could produce directional beams, spasers have highly divergent radiation patterns due to their subwavelength apertures. Here, we theoretically and experimentally demonstrate a new technique for implementing distributed-feedback (DFB) that is distinct from any other previously utilized DFB schemes for semiconductor lasers. The so-termed antenna-feedback scheme leads to single-mode operation in plasmonic lasers, couples the resonant SPP mode to a highly directional far-field radiation pattern, and integrates hybrid SPPs in surrounding medium into the ...

  17. Study on radiation sterilization of electron beam accelerator

    International Nuclear Information System (INIS)

    To study the effects of radiation sterilization of the electron beam, the three species of microorganisms, Escherichia. coli, Staphylococcus aureus and Proteus vulgaris were irradiated with the electron beam, delivered by the electron accelerator independently developed by the Institute of Modern Physics, Chinese Academy of Sciences, and the changes of superoxide dismutase (SOD) activity of these irradiated microorganisms were also tested. The results indicated that the Staphylococcus aureus were fully radio-sterilized with the radiation dosage of 2.0 kGy, but 2.2 kGy to the Escherichia. coli and Proteus vulgaris. Moreover, the data also demonstrated that the irradiation had noticeable effects on the SOD activity of the three microorganisms. (authors)

  18. Development of resistant materials to beam impact and radiation damage

    Science.gov (United States)

    Kawai, Masayoshi; Kokawa, Hiroyuki; Okamura, Hiroshi; Kawasaki, Akira; Yamamura, Tsutomu; Hara, Nobuyoshi; Akao, Noboru; Futakawa, Masatoshi; Kikuchi, Kenji

    2006-09-01

    Materials that have strong resistance to both beam impact (or shock-wave) and radiation damage are required for the beam target of an intense accelerator and space applications. Recently, Futakawa et al. found in their experiments that Kolsterising specimens have a stronger resistance to pitting than SS316 CW. A similar effect can be expected for other hardening treatments, and new material development is hopeful. Accordingly, we have started the development of high-performance materials by organizing the project team from KEK, JAEA and universities. In this paper, the scope of the project is introduced. Recent topics involve the development of intergranular crack (IGC)-resistant austenitic stainless-steel, AlN-TiN ceramics and cladding techniques of thin tantalum or CrN film on a tungsten target by means of a molten-salt method and ion-beam-enhanced deposition. New observations on corrosion resistance are presented.

  19. Beam Loss Position Monitor Using Cerenkov Radiation in Optical Fibers

    CERN Document Server

    Körfer, M

    2005-01-01

    Single pass Free Electron Lasers SASE-FELs are developed for high brightness and short wavelength applications. The VUV-FEL at DESY will reach an average beam power of about 72 kW. To avoid particle losses in the radiation sensitive undulators a collimator system is installed. However, the proper operation of the collimator system needs to be measured with a beam loss monitor. Conventional radiation sensor systems are not suited for the VUV-FEL undulators, because the free space in the undulator gap is less than 1 mm. A Beam Loss Position Monitor (BLPM) based on Cerenkov light in optical fibers allows the monitoring of losses inside the undulator. Electrons with energies above 175 keV generate Cerenkov light during their penetration of the optical fiber. The fast response of the Cerenkov signal is detected with photomultipliers at the end of the irradiated fibers. The beam loss position along the section of interest can be determinate by exploiting the system trigger (bunch clock) of the accelerator system. T...

  20. Radiation Shielding Analysis of Electron Beam Accelerator Facility

    International Nuclear Information System (INIS)

    The objective of this technical report are to establish the radiation shielding technology of a high-energy electron accelerator to the facilities which utilize with electron beam. The technologies of electron beam irradiation(300 KeV -10 MeV) demand on the diverse areas of material processing, surface treatment, treatments on foods or food processing, improvement of metal properties, semiconductors, and ceramics, sterilization of medical goods and equipment, treatment and control of contamination and pollution, and so on. In order to acquire safety design for the protection of personnel from the radiations produced by electron beam accelerators, it is important to develop the radiation shielding analysis technology. The shielding analysis are carried out by which define source term, calculation modelling and computer calculations for 2 MeV and 10 MeV accelerators. And the shielding analysis for irradiation dump shield with 10 MeV accelerators are also performed by solving the complex 3-D geometry and long computer run time problem. The technology development of shielding analysis will be contributed to extend the further high energy accelerator development

  1. Spectral properties of Compton inverse radiation: Application of Compton beams

    Science.gov (United States)

    Bulyak, Eugene; Urakawa, Junji

    2014-05-01

    Compton inverse radiation emitted due to backscattering of laser pulses off the relativistic electrons possesses high spectral density and high energy of photons - in hard x-ray up to gamma-ray energies - because of short wavelength of laser radiation as compared with the classical electromagnetic devices such as undulators. In this report, the possibility of such radiation to monochromatization by means of collimation is studied. Two approaches have been considered for the description of the spectral-angular density of Compton radiation based on the classical field theory and on the quantum electrodynamics. As is shown, both descriptions produce similar total spectra. On the contrary, angular distribution of the radiation is different: the classical approach predicted a more narrow radiation cone. Also proposed and estimated is a method of the 'electronic' monochromatization based on the electronic subtraction of the two images produced by the electron beams with slightly different energies. A 'proof-of-principle' experiment of this method is proposed for the LUXC facility of KEK (Japan).

  2. Radiation processing of natural polymers using low energy electron beam

    International Nuclear Information System (INIS)

    Radiation processing is widely used in Japan and the economic scale of radiation application amounted to about 71 b$ (ratio relative to GDP: 1.7%) in total. It consisted of 60 b$ (85%) in industry, 10 b$ (14%) in medicine and 1 b$ (1%) in agriculture. Irradiation using gamma-ray from 60Co and electron beam is commercially used for the sterilization and modification of materials. Utilization of natural polymers by radiation has been investigated for recycling the natural resources and reducing the environmental pollution. Polysaccharides such as chitosan, sodium alginate, carrageenan, cellulose, pectin were easily degraded by irradiation and induced various kinds of biological activities, i.e. anti-bacterial activity, elicitor activity, plant growth promotion, suppression of environmental stress on plants. Radiation degraded chitosan was effective to enhance the growth of plants in tissue culture. Low energy electron beam (EB) irradiation has a variety of applications and good safety. A self-shielded low energy electron accelerator system needs an initial investment much lower than a 60Co facility. It was demonstrated that the liquid sample irradiation system using low energy EB was effective not only for the preparation of degraded polysaccharides but also for radiation vulcanization of natural rubber latex (RVNRL). Some carbohydrate derivatives, carboxymethylcellulose (CMC), carboxymethyl-starch and carboxymethyl-chitin/chitosan, can be crosslinked under certain radiation condition and produced the biodegradable hydrogel for medical and agricultural use. Treatment of soybean seeds by low energy EB enhanced the growth and the number of rhizobia on the root. (author)

  3. Feasibility and efficacy of simultaneous integrated boost intensity-modulated radiation therapy in patients with limited-disease small cell lung cancer

    OpenAIRE

    Han, Dan; QIN, Qin; Hao, Shaoyu; Huang, Wei; Wei, Yumei; Zhang, Zicheng; Wang, Zhongtang; LI, BAOSHENG

    2014-01-01

    Purpose To evaluate the feasibility and efficacy of simultaneous integrated boost intensity-modulated radiation therapy (SIB-IMRT) in patients with limited-disease small-cell lung cancer (LD-SCLC). Methods Patients with LD-SCLC were treated with SIB-IMRT within 1 week after completion of 2 cycles of induction chemotherapy. Then 2-4 cycles of adjuvant chemotherapy were administered within 1 week after SIB-IMRT. Irradiation was given accelerated hyper-fractionated with the prescribed dose 57Gy ...

  4. Response of TL materials in diagnostic radiology X radiation beams

    International Nuclear Information System (INIS)

    Full text: In diagnostic radiology, TL materials are widely used for dosimetric purposes in clinical beams. Even though the general characteristic of most materials are well documented in literature, the parameters cannot easily be compared, because they derive from different studies, each one with its particularities. Therefore, the main purpose of this study was to compare the performance of different types of TLDs in diagnostic radiology energy range, using standard beams. Seven types of TL materials were used in this study: three types of CaSO4:Dy pellets (conventional CaSO4:Dy pellets, thin CaSO4:Dy pellets, and thin CaSO4:Dy+10%C pellets), sintered Al2O3 pellets (also called Alumina), LiF:Mg,Ti (Harshaw TLD-100), CaF2:Dy (Harshaw TLD-200) and CaF2:Mn (Harshaw TLD-400). For the tests, the materials were irradiated in IEC diagnostic radiology standard beams. Several dosimetric characteristics were evaluated, such as reproducibility, sensitivity, calibration curves, lower dose limits and energy dependence. The results show that the sintered Al2O3 pellets do not have the adequate sensitivity to be used in this dose range. All other materials presented a sensitivity higher than the TLD-100 dosemeters. However, none of the materials, except TLD-100, presented flat energy dependence of response, which is in accordance with literature data. The utilization of those materials for dosimetric purposes should be associated to devices for the determination of the beam effective energy, as, for example, a TLD tandem system. It is also essential to obtain precise calibration curves, in radiation beams really similar to the clinical beams

  5. Successful beam tests for ALICE Transition Radiation Detector

    CERN Multimedia

    2002-01-01

    Another round of beam tests of prototypes for the Transition Radiation Detector (TRD) for ALICE has been completed and there are already some good results. Mass production of the components of the detector will start early next year.   Top view of the setup for the Transition Radiation Detector prototype tests at CERN.On the left, can be seen the full-scale TRD prototype together with four smaller versions. These are busy days for the TRD (Transition Radiation Detector) team of ALICE. Twenty people - mainly from Germany, but also from Russia and Japan - were working hard during the beam tests this autumn at CERN to assess the performance of their detector prototypes. Analysis of the data shows that the TRD can achieve the desired physics goal even for the highest conceivable multiplicities in lead-lead collisions at the LHC. In its final configuration in the ALICE experiment, the TRD will greatly help in identifying high-momentum electrons, which are 'needles in a haystack' that consists mostly of...

  6. Electron beam radiation effects on recycled polyamide-6

    International Nuclear Information System (INIS)

    Applications of electron beam processing in the treatment of polymers are commonly used. The interaction of high energy radiation with polymers may cause permanent modifications in the polymer's physicochemical structure. The induced modifications may result in degradation of the polymer or in improvement of its properties (crosslinking), which are simultaneous and competing processes, depending on the radiation dose utilized. Crosslinking occurs more readily in the polymer's amorphous content and this process makes the glass transition temperature (Tg) of the polymers to increase. Successive recycling cycles promote changes in polymers properties, such as breaking of structure, molecular weight reduction, melt index increase and mechanical resistance reduction. The polyamide-6 resin was recycled for three successive recycling cycles and thi polyamide-6 specimens were molded by the process of injection molding. These specimens were irradiated at the Nuclear Energetic Research Institute (IPEN) radiation facility, on a JOB 188 model accelerator, with a 1.5 MeV electron beam, doses of 200, 300, 400, 500 and 600 kGy, and dose rate of 22.61 kGy/s. The DMA tests were performed using DMA-983 equipment from TA Instruments and two heatings were adopted in order to eliminate the moisture absorption. The X-ray diffraction analysis wa carried out at the Philips PW 1830 model equipment

  7. Theory for beam-plasma millimeter-wave radiation source experiments

    International Nuclear Information System (INIS)

    This paper reports on theoretical studies for millimeter-wave plasma source experiments. In the device, millimeter-wave radiation is generated in a plasma-filled waveguide driven by counter-streaming electron beams. The beams excite electron plasma waves which couple to produce radiation at twice the plasma frequency. Physics topics relevant to the high electron beam current regime are discussed

  8. Local tumor control and cosmetic outcome following breast-conserving surgery and radiation up to a total dose of 56 Gy without boost in breast cancer patients

    International Nuclear Information System (INIS)

    Purpose: To evaluate overall survival, local tumor control and cosmetic outcome after breast-conserving surgery followed by radiotherapy without boost irradiation. Patients and Methods: In a retrospective study 270 breast cancer patients were treated with breast conserving surgery combined with a homogenous radiation of the tumor bearing breast up to a total dose of 56 Gy without local boost irradiation. Mean follow-up was 48 months. Local tumor control, side effects, cosmetic results and contentment with treatment were assessed using physical examinations and interviews based on a standardized questionnaire. Results: Cause-specific survival at 5 years after treatment was 88.3%, actuarial disease-free survival at 5 years was 76.1%. Within 23 to 78 months after treatment 12 patients suffered from ipsilateral breast recurrence. The actuarial freedom from local recurrence (single tumor manifestation) was 96.8% at 5 years after treatment, 89% at 10 years. The occurrence of local failures was not significantly correlated to tumor size, margins, grading, nodal status, age or lymphangiosis. 15.6% of the patients developed distant metastases. In all patients treatment was performed without interruption. Side effects were predominantly of mild degree, no severe side effects were detected. 73% of physicians and 81% of patients scored their cosmetic outcome as excellent or good. 93% of patients would again decide in favor of this procedure. Whereas, use of adjuvant chemotherapy as well as subcutaneous reconstruction of breast tissue did not significantly affect breast cosmesis, analysis demonstrated impaired cosmetic results related to a larger breast size. Conclusion: The data of this study show that tumor control achieved by breast conserving surgery in combination with a radiation technique up to a total dose of 56 Gy which omits boost irradiation is within the range of literature data. Side effects of the therapy were tolerable. The treatment displayed a good

  9. Electron beam radiation effects on recycled polyamide-6

    International Nuclear Information System (INIS)

    The aim of this work was to study the ionizing radiation effects on recycled polyamide-6. This polymer was irradiated with a 1.5 MeV electron beam at different doses. The glass transition of the samples was determined by dynamic mechanical analyses (DMA) measurements and the crystallinity was observed through the X-ray diffraction diagrams. It was observed that crosslinking may have occurred in the irradiated samples of virgin and recycled polyamide-6 and the crystallinity has not changed. (author)

  10. Radiation produced by the modulated electron beam of a free electron laser

    OpenAIRE

    Neighbours, John Robert; Maruyama, Xavier K.; Buskirk, Fred Ramon

    1986-01-01

    The electron beam in a free electron laser (FEL) becomes axially modulated at the optical wave length of the FEL radiation. This electron beam passed through a gas may produce intense Cerenkov radiation. The effects of the radial and axial dimension of the electron bunches on the radiation are explored

  11. Adjuvant continuous infusion 5-FU, whole-abdominal radiation, and tumor bed boost in high-risk stage III colon carcinoma: a southwest oncology group pilot study

    International Nuclear Information System (INIS)

    Purpose: Results of a combined modality adjuvant pilot program of low-dose continuous-infusion 5-fluorouracil, whole-abdominal radiation, and tumor bed boost in patients with colon cancer with involved nodes and serosal involvement are presented. Methods and Materials: Forty-one eligible patients with completely resected T3N1-2M0 colon cancer (modified Astler-Coller C2) were treated with 5-fluorouracil (5-FU) at a dose of 200 mg/m2/day by continuous infusion and 30 Gy of concomitant whole-abdominal radiation in 1 Gy fractions. An additional 16 Gy boost to the tumor bed was administered in 1.6 Gy fractions. After completion of combined modality treatment and a 21-day rest period, patients received 4 days of 5-FU at a dose of 1000 mg/m2 by continuous infusion every 28 days for nine cycles. Results: Five-year disease-free and overall survival estimates were 58 and 67%, respectively, for all T3N1-2 patients. Five-year disease-free and overall survival estimates for the 19 patients with four or fewer nodes were both 61%. Five-year disease-free survival and overall survival estimates for the 20 patients with more than four involved nodes were 55% and 74%, respectively (the exact number of involved nodes were unknown for two patients). Disease-free and overall survival estimates for patients treated with 5-FU and radiation compare favorably to the 5-FU plus levamisole arm of the intergroup adjuvant colon study (Int 0035/SWOG 8591) in patients with more than four positive nodes where the 5-year disease-free and overall survival estimates were 35% and 39%, respectively. Disease-free and overall survival estimates for patients with four or fewer nodes in the 5-FU plus levamisole arm of the intergroup study were 64 and 68%, which is not markedly different from results obtained with radiation and 5-FU in the current study. There were no treatment-related fatalities. Seventeen percent of patients had severe and 7% had life-threatening toxicity of any kind. One patient had an

  12. Thin silicon strip detectors for beam monitoring in Micro-beam Radiation Therapy

    International Nuclear Information System (INIS)

    Microbeam Radiation Therapy (MRT) is an emerging cancer treatment that is currently being developed at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. This technique uses a highly collimated and fractionated X-ray beam array with extremely high dose rate and very small divergence, to benefit from the dose-volume effect, thus sparing healthy tissue. In case of any beam anomalies and system malfunctions, special safety measures must be installed, such as an emergency safety shutter that requires continuous monitoring of the beam intensity profile. Within the 3DMiMic project, a novel silicon strip detector that can tackle the special features of MRT, such as the extremely high spatial resolution and dose rate, has been developed to be part of the safety shutter system. The first prototypes have been successfully fabricated, and experiments aimed to demonstrate their suitability for this unique application have been performed. Design, fabrication and the experimental results as well as any identified inadequacies for future optimisation are reported and discussed in this paper

  13. Thin silicon strip detectors for beam monitoring in Micro-beam Radiation Therapy

    Science.gov (United States)

    Povoli, M.; Alagoz, E.; Bravin, A.; Cornelius, I.; Bräuer-Krisch, E.; Fournier, P.; Hansen, T. E.; Kok, A.; Lerch, M.; Monakhov, E.; Morse, J.; Petasecca, M.; Requardt, H.; Rosenfeld, A. B.; Röhrich, D.; Sandaker, H.; Salomé, M.; Stugu, B.

    2015-11-01

    Microbeam Radiation Therapy (MRT) is an emerging cancer treatment that is currently being developed at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. This technique uses a highly collimated and fractionated X-ray beam array with extremely high dose rate and very small divergence, to benefit from the dose-volume effect, thus sparing healthy tissue. In case of any beam anomalies and system malfunctions, special safety measures must be installed, such as an emergency safety shutter that requires continuous monitoring of the beam intensity profile. Within the 3DMiMic project, a novel silicon strip detector that can tackle the special features of MRT, such as the extremely high spatial resolution and dose rate, has been developed to be part of the safety shutter system. The first prototypes have been successfully fabricated, and experiments aimed to demonstrate their suitability for this unique application have been performed. Design, fabrication and the experimental results as well as any identified inadequacies for future optimisation are reported and discussed in this paper.

  14. PIC code KARAT simulation of different types of polarization radiation generated by relativistic electron beam

    Science.gov (United States)

    Artyomov, K. P.; Ryzhov, V. V.; Naumenko, G. A.; Shevelev, M. V.

    2012-05-01

    Different types of polarization radiation generated by a relativistic electron beam are simulated using fully electromagnetic particle-in-cell (PIC) code KARAT. The simulation results for diffraction radiation, transition radiation, Smith-Purcell radiation and Vavilov-Cherenkov radiation are in a good agreement with experimental data and analytical models. Modern PIC simulation is a good tool to check and predict experimental results.

  15. PIC code KARAT simulation of different types of polarization radiation generated by relativistic electron beam

    International Nuclear Information System (INIS)

    Different types of polarization radiation generated by a relativistic electron beam are simulated using fully electromagnetic particle-in-cell (PIC) code KARAT. The simulation results for diffraction radiation, transition radiation, Smith-Purcell radiation and Vavilov-Cherenkov radiation are in a good agreement with experimental data and analytical models. Modern PIC simulation is a good tool to check and predict experimental results.

  16. Radiation Exposure of Abdominal Cone Beam Computed Tomography

    International Nuclear Information System (INIS)

    PurposeTo evaluate patients radiation exposure of abdominal C-arm cone beam computed tomography (CBCT).MethodsThis prospective study was approved by the institutional review board; written, informed consent was waived. Radiation exposure of abdominal CBCT was evaluated in 40 patients who underwent CBCT during endovascular interventions. Dose area product (DAP) of CBCT was documented and effective dose (ED) was estimated based on organ doses using dedicated Monte Carlo simulation software with consideration of X-ray field location and patients’ individual body weight and height. Weight-dependent ED per DAP conversion factors were calculated. CBCT radiation dose was compared to radiation dose of procedural fluoroscopy. CBCT dose-related risk for cancer was assessed.ResultsMean ED of abdominal CBCT was 4.3 mSv (95 % confidence interval [CI] 3.9; 4.8 mSv, range 1.1–7.4 mSv). ED was significantly higher in the upper than in the lower abdomen (p = 0.003) and increased with patients’ weight (r = 0.55, slope = 0.045 mSv/kg, p < 0.001). Radiation exposure of CBCT corresponded to the radiation exposure of on average 7.2 fluoroscopy minutes (95 % CI 5.5; 8.8 min) in the same region of interest. Lifetime risk of exposure related cancer death was 0.033 % or less depending on age and weight.ConclusionsMean ED of abdominal CBCT was 4.3 mSv depending on X-ray field location and body weight

  17. Radiation Exposure of Abdominal Cone Beam Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Sailer, Anna M., E-mail: anni.sailer@mumc.nl [Maastricht University Medical Centre (MUMC), Department of Radiology (Netherlands); Schurink, Geert Willem H., E-mail: gwh.schurink@mumc.nl [Maastricht University Medical Centre, Department of Surgery (Netherlands); Wildberger, Joachim E., E-mail: j.wildberger@mumc.nl; Graaf, Rick de, E-mail: r.de.graaf@mumc.nl; Zwam, Willem H. van, E-mail: w.van.zwam@mumc.nl; Haan, Michiel W. de, E-mail: m.de.haan@mumc.nl; Kemerink, Gerrit J., E-mail: gerrit.kemerink@mumc.nl; Jeukens, Cécile R. L. P. N., E-mail: cecile.jeukens@mumc.nl [Maastricht University Medical Centre (MUMC), Department of Radiology (Netherlands)

    2015-02-15

    PurposeTo evaluate patients radiation exposure of abdominal C-arm cone beam computed tomography (CBCT).MethodsThis prospective study was approved by the institutional review board; written, informed consent was waived. Radiation exposure of abdominal CBCT was evaluated in 40 patients who underwent CBCT during endovascular interventions. Dose area product (DAP) of CBCT was documented and effective dose (ED) was estimated based on organ doses using dedicated Monte Carlo simulation software with consideration of X-ray field location and patients’ individual body weight and height. Weight-dependent ED per DAP conversion factors were calculated. CBCT radiation dose was compared to radiation dose of procedural fluoroscopy. CBCT dose-related risk for cancer was assessed.ResultsMean ED of abdominal CBCT was 4.3 mSv (95 % confidence interval [CI] 3.9; 4.8 mSv, range 1.1–7.4 mSv). ED was significantly higher in the upper than in the lower abdomen (p = 0.003) and increased with patients’ weight (r = 0.55, slope = 0.045 mSv/kg, p < 0.001). Radiation exposure of CBCT corresponded to the radiation exposure of on average 7.2 fluoroscopy minutes (95 % CI 5.5; 8.8 min) in the same region of interest. Lifetime risk of exposure related cancer death was 0.033 % or less depending on age and weight.ConclusionsMean ED of abdominal CBCT was 4.3 mSv depending on X-ray field location and body weight.

  18. Radiation Safety System for SPIDER Neutral Beam Accelerator

    Science.gov (United States)

    Sandri, S.; Coniglio, A.; D'Arienzo, M.; Poggi, C.

    2011-12-01

    SPIDER (Source for Production of Ion of Deuterium Extracted from RF Plasma only) and MITICA (Megavolt ITER Injector Concept Advanced) are the ITER neutral beam injector (NBI) testing facilities of the PRIMA (Padova Research Injector Megavolt Accelerated) Center. Both injectors accelerate negative deuterium ions with a maximum energy of 1 MeV for MITICA and 100 keV for SPIDER with a maximum beam current of 40 A for both experiments. The SPIDER facility is classified in Italy as a particle accelerator. At present, the design of the radiation safety system for the facility has been completed and the relevant reports have been presented to the Italian regulatory authorities. Before SPIDER can operate, approval must be obtained from the Italian Regulatory Authority Board (IRAB) following a detailed licensing process. In the present work, the main project information and criteria for the SPIDER injector source are reported together with the analysis of hypothetical accidental situations and safety issues considerations. Neutron and photon nuclear analysis is presented, along with special shielding solutions designed to meet Italian regulatory dose limits. The contribution of activated corrosion products (ACP) to external exposure of workers has also been assessed. Nuclear analysis indicates that the photon contribution to worker external exposure is negligible, and the neutron dose can be considered by far the main radiation protection issue. Our results confirm that the injector has no important radiological impact on the population living around the facility.

  19. Radiation Safety System for SPIDER Neutral Beam Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Sandri, S.; Poggi, C. [ENEA, Radiation Protection Institute, IRP-FUAC, Frascati (Italy); Coniglio, A. [Medical Physics Department, S. Giovanni Calibita Hospital, Fatebenefratelli, Isola Tiberina, Roma (Italy); D' Arienzo, M. [ENEA, Ionizing Radiation Metrology National Institute, METR, Casaccia, Rome (Italy)

    2011-12-13

    SPIDER (Source for Production of Ion of Deuterium Extracted from RF Plasma only) and MITICA (Megavolt ITER Injector Concept Advanced) are the ITER neutral beam injector (NBI) testing facilities of the PRIMA (Padova Research Injector Megavolt Accelerated) Center. Both injectors accelerate negative deuterium ions with a maximum energy of 1 MeV for MITICA and 100 keV for SPIDER with a maximum beam current of 40 A for both experiments. The SPIDER facility is classified in Italy as a particle accelerator. At present, the design of the radiation safety system for the facility has been completed and the relevant reports have been presented to the Italian regulatory authorities. Before SPIDER can operate, approval must be obtained from the Italian Regulatory Authority Board (IRAB) following a detailed licensing process. In the present work, the main project information and criteria for the SPIDER injector source are reported together with the analysis of hypothetical accidental situations and safety issues considerations. Neutron and photon nuclear analysis is presented, along with special shielding solutions designed to meet Italian regulatory dose limits. The contribution of activated corrosion products (ACP) to external exposure of workers has also been assessed. Nuclear analysis indicates that the photon contribution to worker external exposure is negligible, and the neutron dose can be considered by far the main radiation protection issue. Our results confirm that the injector has no important radiological impact on the population living around the facility.

  20. Cone Beam CT: radiation protection aspects and quality control

    International Nuclear Information System (INIS)

    The technology related to Cone Beam Computed Tomography (CBCT) give three-dimensional (3D) diagnostic results. It allows to give to the patient doses much lower than traditional TC technique. This type of equipment, introduced relatively recently, is rapidly spreading in the field of Radiology and in particular dental and maxillofacial and is meant to be used more and more frequently in clinical practice and in the coming years there will be an increase of radiological examinations performed with this technique. In January 2012 the ANPEQ formed, within the Permanent Commission's technical aspects of radiation protection-health ' the Working Party ' Cone Beam CT ' with the intention to draw up an operating report that provide guidelines for radiological protection of the operators and of the population, in full respect of the relevant operating areas by other operators, such as physicists, doctors etc. In the course of work it is proved the opportunity to share what worked with other associations dealing with radiation protection, AIFM (Associazione Italiana di Fisica Medica), AIRP (Associazione Italiana di Radioprotezione), AIRM (Associazione Italiana di Radioprotezione Medica), organising a joint Conference on CBCT which was held at pisa on March 1, 2013. This report collects most of the contributions presented by individual speakers who participated in the Conference, by then state of the art in this innovative method.

  1. Focal dose escalation using FDG-PET-guided intensity-modulated radiation therapy boost for postoperative local recurrent rectal cancer: a planning study with comparison of DVH and NTCP

    International Nuclear Information System (INIS)

    To evaluate the safety of focal dose escalation to regions with standardized uptake value (SUV) >2.0 using intensity-modulated radiation therapy (IMRT) by comparison of radiotherapy plans using dose-volume histograms (DVHs) and normal tissue complication probability (NTCP) for postoperative local recurrent rectal cancer First, we performed conventional radiotherapy with 40 Gy/20 fr. (CRT 40 Gy) for 12 patients with postoperative local recurrent rectal cancer, and then we performed FDG-PET/CT radiotherapy planning for those patients. We defined the regions with SUV > 2.0 as biological target volume (BTV) and made three boost plans for each patient: 1) CRT boost plan, 2) IMRT without dose-painting boost plan, and 3) IMRT with dose-painting boost plan. The total boost dose was 20 Gy. In IMRT with dose-painting boost plan, we increased the dose for BTV+5 mm by 30% of the prescribed dose. We added CRT boost plan to CRT 40 Gy (summed plan 1), IMRT without dose-painting boost plan to CRT 40 Gy (summed plan 2) and IMRT with dose-painting boost plan to CRT 40 Gy (summed plan 3), and we compared those plans using DVHs and NTCP. Dmean of PTV-PET and that of PTV-CT were 26.5 Gy and 21.3 Gy, respectively. V50 of small bowel PRV in summed plan 1 was significantly higher than those in other plans ((summed plan 1 vs. summed plan 2 vs. summed plan 3: 47.11 ± 45.33 cm3 vs. 40.63 ± 39.13 cm3 vs. 41.25 ± 39.96 cm3(p < 0.01, respectively)). There were no significant differences in V30, V40, V60, Dmean or NTCP of small bowel PRV. FDG-PET-guided IMRT can facilitate focal dose-escalation to regions with SUV above 2.0 for postoperative local recurrent rectal cancer

  2. Normal tissue tolerance to external beam radiation therapy: The vagina

    International Nuclear Information System (INIS)

    The vagina is a virtual cavity involved in sexual reproduction field. Due to its anatomical location, it may be exposed in whole or in part to ionizing radiation in external radiotherapy and/or brachytherapy of the pelvic region. This review aims to describe the vaginal acute and late side effects due to radiation, probably inadequately reported in the literature. Medline and PubMed literature searches were performed using the keywords -vaginal - radiotherapy - toxicity. The acute and late functional changes after external beam radiation consist mainly of drought. Their incidences are poorly described in the literature and the delivered doses even less. Recommendations are non-existent as the normal tissue complication probability (NTCP). Brachytherapy delivers high and heterogeneous doses, making it difficult to estimate the dose. The concomitant administration of chemotherapy appears to be a factor increasing the risk of toxicity. Modern techniques of conformal radiotherapy with modulated intensity appear to have little impact on this body. Only a maximum dose on each third of the vagina appears to be currently proposed to avoid the risk of side effects. (authors)

  3. Concurrent weekly docetaxel and concomitant boost radiation therapy in the treatment of locally advanced squamous cell cancer of the head and neck

    International Nuclear Information System (INIS)

    Purpose: In a Phase I/II trial, we investigated concurrent weekly docetaxel and concomitant boost radiation in patients with locally advanced squamous cell cancer of the head and neck (SCCHN) after induction chemotherapy. Patients and Methods: Patients presented with American Joint Committee on Cancer Stage III/IV and were treated initially with induction chemotherapy using cisplatinum/5-fluorouracil (PF), carboplatinum-5-FU, or docetaxel-PF. Patients then received docetaxel four times weekly with concomitant boost (CB) radiation (1.8 Gy once-daily X20, 1.8/1.5 Gy twice a day). Fifteen patients each received 20 mg/M2 and 25 mg/M2. Results: Thirty-one patients were enrolled and 30 were evaluable for response and toxicity. Median follow-up was 42 months (range, 27-63 months). Primary sites were: oropharynx 19, oral cavity 2, larynx/hypopharynx 5, and unknown primary 4. Eighty-seven percent of patients had N2/N3 disease; 60% had T3/T4 disease. Twenty percent of patients had a complete response (CR) to induction chemotherapy. After chemoradiotherapy, 21 of 30 patients had a CR, 2 had progressive disease, and 7 had partial response (PR). Nineteen of 26 patients presenting with neck disease had neck dissections, and 7 of 19 were positive. Ninety-three percent of all patients were rendered disease-free after all planned therapy. Treatment failed in 8 patients, and 7 have died of disease. An additional patient died with no evidence of disease. Twenty-one patients (70%) are currently alive with no evidence of disease. No acute dose-limiting toxicity was observed at either dose level. Conclusions: This intensive treatment regimen of concurrent docetaxel/concomitant boost radiation and surgery after induction chemotherapy in poor prognosis patients yields good local regional control and survival. Docetaxel/CB chemoradiotherapy represents an aggressive alternative regimen to platinum-based chemoradiotherapy or surgery in patients who have a poor response to induction

  4. Easy graphical display of beam directions in three-dimensional converging radiation therapy. Proposal for a radiation map

    International Nuclear Information System (INIS)

    In stereotactic radiosurgery, non-coplanar isocentric beams are employed to concentrate the dose distribution on the planning target volume (PTV). However, the directions of incident beams must be determined with great care by using a digitally reconstructed beam's eye view (BEV) to prevent the irradiation of organs at risk. We present a new method of 2-dimensional graphical representation (radiation map) to facilitate the understanding of 3-dimensional relationships between incident beams and critical organs. After determining the isocenter and beam diameter, beam directions and critical organs are projected onto the imaginary sphere centered on the isocenter. The coordinate of the beam directions and the organs at risk can be expressed by latitude and longitude on the sphere. The contours of the organs at risk are displayed with a margin of the radius of the radiation beam. Mirror images of the critical organs are also displayed to prevent irradiation by the opposing beams. The radiation map could be produced within 5 minutes using a workstation. Radiation maps, like DVH, will be very useful in the evaluation of radiation treatment planning. (author)

  5. Performance of ionization chambers in X radiation beams, radioprotection level

    International Nuclear Information System (INIS)

    Narrow beams, radioprotection level, were implanted in an X ray system, based on ISO 4037-1, as recommended by IAEA (SRS 16). Energy dependency tests were carried out and short-term stability in ionization chambers for use in radiation protection of trademark Physikalisch-Technische Werkstaetten (PTW), 32002 and 23361 models. The ionization chambers were studied with regard to short-term stability within the program of quality control of the laboratory, with a 90Sr + 90Y. The results of the short-term stability test were compared with the recommendations of IEC 60731, respect to dosemeters used in radiotherapy, since this standard presents the more restrictive limits with regard to the behaviour of ionization chambers. All cameras showed results within the limits recommended by this standard. With respect to the energy dependency of the response, the model Chamber 32002 presented a maximum dependence of only 2.7%, and the model Chamber 23361, 4.5%

  6. The dynamical dipole radiation in dissipative collisions with exotic beams

    International Nuclear Information System (INIS)

    Heavy Ion Collisions (HIC) represent a unique tool to probe the in-medium nuclear interaction in regions away from saturation. In this work we present a selection of reaction observables in dissipative collisions particularly sensitive to the isovector part of the interaction, i.e. to the symmetry term of the nuclear Equation of State (EoS). At low energies the behavior of the symmetry energy around saturation influences dissipation and fragment production mechanisms. We will first discuss the recently observed Dynamical Dipole Radiation, due to a collective neutron-proton oscillation during the charge equilibration in fusion and deep-inelastic collisions. We will review in detail all the main properties, yield, spectrum, damping and angular distributions, revealing important isospin effects. Reactions induced by unstable 132Sn beams appear to be very promising tools to test the sub-saturation Isovector EoS. Predictions are also presented for deep-inelastic and fragmentation collisions induced by neutron rich projectiles. The importance of studying violent collisions with radioactive beams at low and Fermi energies is finally stressed. (author)

  7. FULL ELECTROMAGNETIC FEL SIMULATION VIA THE LORENTZ-BOOSTED FRAME TRANSFORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Fawley, William; Vay, Jean-Luc

    2010-08-16

    Numerical electromagnetic simulation of some systems containing charged particles with highly relativistic directed motion can by speeded up by orders of magnitude by choice of the proper Lorentz-boosted frame. A particularly good application for calculation in a boosted frame isthat of short wavelength free-electron lasers (FELs) where a high energy electron beam with small fractional energy spread interacts with a static magnetic undulator. In the optimal boost frame (i.e., the ponderomotive rest frame), the red-shifted FEL radiation and blue-shifted undulator field have identical wavelengths and the number of required longitudinal grid cells and time-steps for fully electromagnetic simulation (relative to the laboratory frame) decrease by factors of gamma^2 each. In theory, boosted frame EM codes permit direct study of FEL problems for which the eikonal approximation for propagation of the radiation field and wiggler-period-averaging for the particle-field interaction may be suspect. We have adapted the WARP code to apply this method to several electromagnetic FEL problems including spontaneous emission, strong exponential gain in a seeded, single pass amplifier configuration, and emission from e-beams in undulators with multiple harmonic components. WARP has a standard relativistic macroparticle mover and a fully 3-D electromagnetic field solver. We discuss our boosted frame results and compare with those obtained using the ?standard? eikonal FEL simulation approach.

  8. Radiation sterilization of fluoroquinolones in solid state: Investigation of effect of gamma radiation and electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Babita K., E-mail: singhbab2001@rediffmail.co [Department of Chemistry, RTM Nagpur University Campus, Amravati Road, Nagpur 440033 (India); Central Forensic Science Laboratory, Ramanthapur, Hyderabad 500013 (India); Parwate, Dilip V. [Department of Chemistry, RTM Nagpur University Campus, Amravati Road, Nagpur 440033 (India); Dassarma, Indrani B. [Jhulelal Institute of Technology, Nagpur (India); Shukla, Sudhir K. [Central Forensic Science Laboratory, Ramanthapur, Hyderabad 500013 (India)

    2010-09-15

    The effect of gamma radiation from {sup 60}Co source and 2 MeV electron beam was studied on two fluoroquinolone antibiotics viz norfloxacin and gatifloxacin in the solid state. The changes in reflectance spectrum, yellowness index, vibrational characteristics, thermal behavior, UV spectrum, chemical potency (HPLC) and microbiological potency were investigated. ESR measurement gave the number of free radical species formed and their population. The nature of final radiolytic impurities was assessed by studying the HPLC impurity profile. Both norfloxacin and gatifloxacin were observed to be radiation resistant, and did not show significant changes in their physico-chemical properties. They could be radiation sterilized at a dose of 25 kGy.

  9. Normal tissue tolerance to external beam radiation therapy: Small bowel

    International Nuclear Information System (INIS)

    The small bowel is a hollow organ involved in the transit and absorption of food. In relation to its anatomical location, a significant amount of this organ is exposed in whole or in part to ionizing radiation in external radiotherapy during abdominal or pelvic irradiation either for primary cancers or metastasis. The acute functional changes during external beam radiation are mainly leading to diarrhea, abdominal pain and bloating. The main late side effects of irradiation of the small intestine are chronic diarrhea, malabsorption with steatorrhoea, abdominal spasms, intestinal obstruction, bleeding and fistulas. The architecture of the small intestine may be considered as parallel with a significant correlation between the irradiated volume of small bowel and the likelihood of acute toxicity, whatever the dose. The literature analysis recommends to consider the volume of small bowel receiving 15 Gy (threshold of 100 to 200 cm3) but also 30 and 50 Gy (thresholds of 35 to 300 cm3, depending on the level of dose considered). Modern techniques of conformal radiotherapy with modulated intensity will probably have beneficial impact on small bowel toxicity. (authors)

  10. Study of Synchrotron Radiation for the Electron Beam Polarimeter for the MEIC

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-06

    This is a look at the synchrotron radiation coming from the chicane in the electron beam line for the MEIC design. The power density on the beam pipe as well as transmission through the beam pipe is studied. The optics design is version 12.

  11. A phase I/II study of external beam radiation, brachytherapy and concurrent chemotherapy in localized cancer of the esophagus (RTOG 9207)

    International Nuclear Information System (INIS)

    Introduction: A multi-institutional, prospective study was designed to determine the feasibility and toxicity of chemotherapy, external beam irradiation and esophageal brachytherapy (EB) in a potentially curable group of patients with adenocarcinoma or squamous cell carcinoma of the esophagus. Methods: Planned treatment was 50 Gy external beam radiation (25 fractions/5 wks) followed 2 weeks later by EB (either HDR 5 Gy wks 8,9 and 10 for a total of 15 Gy or LDR 20 Gy wk 8). The protocol was later revised to delete the LDR alternative due to poor accrual and decrease the HDR dose to 10 Gy, ie 5 Gy wks 8 and 9. Chemotherapy was given wks 1,5,8 and 11 with DDP 75 mg/m2 and 5-FU 1000 mg/m2/24 hrs, 96 hour infusion. Data is available on 50 patients (46 squamous, 3 adenocarcinoma) treated on the HDR alternative (EB dose 15 Gy and 10 Gy in 40 and 10 patients, respectively. Results: Thirty-five patients (70%) were able to complete external beam, EB and at least 2 courses of chemotherapy. Estimated survival rate at 12 months is 48%. Life-threatening toxicity or death occurred in 13 (26%) and 4 (8%) patients, respectively. Treatment-related esophageal fistulas occurred in 6 patients (12%) at 0.5 to 6.2 months from the first day of brachytherapy, leading to death in 3. So far all treatment-related fistulas occurred in the 15 Gy EB group. Conclusions: Survival following this combination of chemotherapy, external beam radiation and EB does not appear to be different from survival seen following chemotherapy and external beam radiation only. Based on the high incidence of fistulas, we urge extreme caution in employing EB as a boost following concurrent chemotherapy and external beam radiation with the schema utilized in this prospective study

  12. Design, construction and characterization of special ionization chambers for X radiation beams monitoring

    International Nuclear Information System (INIS)

    X radiation equipment may show fluctuations in the radiation beam intensity, as they are connected to the power net. These intensity variations can, in turn, modify the air kerma rate produced by this radiation beam. In a calibration laboratory, where radiation detectors (from clinics and hospital services) are calibrated, variations in the radiation beam intensity may cause an error in the absorbed dose determination. The monitor ionization chambers are used to verify the radiation beam intensity constancy, and to provide a correction for possible fluctuations. In this work, monitor ionization chambers for X radiation beams were designed, assembled and characterized. The developed ionization chambers have an innovative design, ring-shaped, with aluminium or graphite electrodes. These ring-shaped ionization chambers have the advantage of not interfering in the direct radiation beams. A double-volume ionization chamber with graphite electrodes was also developed. This ionization chamber is similar to the commercial monitor ionization chamber used in the Calibration Laboratory of the Instituto de Pesquisas Energeticas e Nucleares. All developed ionization chambers were tested in several standardized radiation beams and their performances were compared with those of commercial ionization chambers. The results show that two of the four ionization chambers developed showed performance comparable to that of the commercial ionization chambers tested. Besides presenting good results, the ionization chambers were designed and manufactured using low cost materials, which are easily found on the Brazilian market. (author)

  13. Spontaneous short-wave radiation of high-current electron beam

    International Nuclear Information System (INIS)

    Angular and spectral characteristics of spontaneous radiation of high-current electron beam in a proper magnetic field are theoretically investigated. The model of a cylindrically- symmetric non rotating stationary beam the space charge of which is completely compensated by a motionless ion background has been used. It is shown that the radiation considerably depends on the beam current, its directivity with current increase drops, total intensity grows, but the spectrum widens

  14. Imaging and characterization of primary and secondary radiation in ion beam therapy

    Science.gov (United States)

    Granja, Carlos; Martisikova, Maria; Jakubek, Jan; Opalka, Lukas; Gwosch, Klaus

    2016-07-01

    Imaging in ion beam therapy is an essential and increasingly significant tool for treatment planning and radiation and dose deposition verification. Efforts aim at providing precise radiation field characterization and online monitoring of radiation dose distribution. A review is given of the research and methodology of quantum-imaging, composition, spectral and directional characterization of the mixed-radiation fields in proton and light ion beam therapy developed by the IEAP CTU Prague and HIT Heidelberg group. Results include non-invasive imaging of dose deposition and primary beam online monitoring.

  15. Dose analysis of boost irradiation of parapharyngeal space in nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Parapharyngeal space (PPS) is one of the common spreads of nasopharyngeal carcinoma (NPC). Since early eighties boost treatment has been routinely given to patients with PPS involvement. The use of oblique facio-cervical field in this treatment posed difficulty in assessing the dose distribution before the 3-D computer systems are available. This study evaluated the variations of dose distribution by different boost techniques on fifteen patients with PPS involvement using 3-D computer planning system. Comparisons were made between different radiation types, photon energies and modes of collimation respectively. Results showed that the dose distributions in the boost treatment were acceptable, as they did not bring the total doses of the normal structures exceeding their tolerance. There was little difference between 6 and 10 MV photons, but significant differences were found between photon and electron beams. Photon beams were better than the electron beams in giving lower doses to the spinal cord and the TM joint with more homogeneous dose to the target volume, whereas electron beams gave better sparing of the lens and temporal lobe. For the photon beams, half-blocked beam was superior to symmetrical beam in reducing the brain stem dose, but there was no advantage to the rest of normal structures. Copyright (1999) Australian Institute of Radiography

  16. Concurrent chemo-irradiation using accelerated concomitant boost radiation therapy in loco-regionally advanced head and neck squamous cell carcinomas

    Directory of Open Access Journals (Sweden)

    Vivek R

    2006-01-01

    Full Text Available Purpose: To investigate the feasibility of combining concomitant boost-accelerated radiation regimen (ACB with full-dose mono-chemotherapy using cisplatin and to assess its local response and acute toxicity patterns in patients with advanced loco-regional head and neck squamous cell carcinoma (HNSCC. Materials and Methods: Between July 2004 and August 2005, a pilot study involving 27 patients with stage III to IVB (AJCC-6th HNSCC of the oropharynx, hypopharynx and larynx who met the eligibility criteria was undertaken. Twenty-four of these patients (median age - 53 years were analyzable. The radiation dose was 72 Gy in 42 fractions over 6 weeks, delivered in one daily fraction of 1.8 Gy during the first 3.5 weeks and two fractions per day, 1.8 Gy and 1.5 Gy boost-separated by> 6 h interval, during the last 2.5 weeks. cisplatin, 100 mg/m2, was given in intravenous (i.v. infusion on day 1 and day 22. Tumor and clinical status were assessed and acute toxicities were graded. Results: Out of 27 patients, 24 patients received both radiation and chemotherapy as per protocol and were available for analysis. The loco-regional response rates were as follows: an overall response of 95.8% (23 patients, a complete response of 79.1% (19 patients, a partial response of 16.7% (4 patients and progressive disease in 4.2% (1 patient. Dysphagia, nausea, vomiting and bone marrow suppression were the most common side effects and were associated with cisplatin administration. One patient (3.7% died of complications (pneumonia and sepsis, 3 patients (12.5% had acute grade 4 toxicity and 21 patients (87.5% had acute grade 3 (17 patients or grade 2 (4 patients toxicity. Conclusion: This data shows that it is feasible to combine ACB and full-dose mono-chemotherapy using cisplatin with manageable, although substantial, toxicity. The compliance to therapy was high and the loco-regional response achieved compared favorably with ACB alone or other concurrent chemoradiation

  17. To boost or not boost in radiotherapy

    International Nuclear Information System (INIS)

    The aim of this paper it to analyse and discuss standard definition of the 'boost' procedure in relation to clinical results and new forms of the boost designed on physical and radiobiological bases. Seventeen sets of clinical data including over 5000 cases cancer with different tumour stages and locations and treated with various forms of 'boost' method have been subtracted from literature. Effectiveness of boost is analyzed regarding its place in combined treatment, timing and subvolume involved. Radiobiological parameter of D10 and normalization method for biologically equivalent doses and dose intensity are used to simulated cold and not subvolumes (hills and dales) and its influence of effectiveness on the boost delivery. Sequential and concomitant boost using external irradiation, although commonly used, offers LTC benefit lower than expected. Brachytherapy, intraoperative irradiation and concurrent chemotherapy boost methods appear more effective. Conformal radiotherapy, with or without dose-intensity modulation, allows heterogeneous increase in dose intensity within the target volume and can be used to integrate the 'boost dose' into baseline treatment (Simultaneous Integrated Boost and SIB). Analysis of interrelationships between boost-dose; boost volume and its timing shows that a TCP benefit from boosting can be expected when a relatively large part of the target volume is involved. Increase in boost dose above 1.2-1.3 of baseline dose using 'standard' methods does not substantially further increase the achieved TCP benefit unless hypoxic cells are a problem. Any small uncertainties in treatment planning can ruin all potential beneficial effect of the boost. For example, a 50% dose deficit in a very small (e.g. 1%) volume of target can decrease TCP to zero. Therefore boost benefits should be carefully weighed against any risk of cold spots in the target volume. Pros and cons in discussion of the role of boost in radiotherapy lead to the important

  18. Registering prostate external beam radiotherapy with a boost from high-dose-rate brachytherapy: a comparative evaluation of deformable registration algorithms

    International Nuclear Information System (INIS)

    Registering CTs for patients receiving external beam radiotherapy (EBRT) with a boost dose from high-dose-rate brachytherapy (HDR) can be challenging due to considerable image discrepancies (e.g. rectal fillings, HDR needles, HDR artefacts and HDR rectal packing materials). This study is the first to comparatively evaluate image processing and registration methods used to register the rectums in EBRT and HDR CTs of prostate cancer patients. The focus is on the rectum due to planned future analysis of rectal dose-volume response. For 64 patients, the EBRT CT was retrospectively registered to the HDR CT with rigid registration and non-rigid registration methods in VelocityAI. Image processing was undertaken on the HDR CT and the rigidly-registered EBRT CT to reduce the impact of discriminating features on alternative non-rigid registration methods applied in the software suite for Deformable Image Registration and Adaptive Radiotherapy Research (DIRART) using the Horn-Schunck optical flow and Demons algorithms. The propagated EBRT-rectum structures were compared with the HDR structure using the Dice similarity coefficient (DSC), Hausdorff distance (HD) and average surface distance (ASD). The image similarity was compared using mutual information (MI) and root mean squared error (MSE). The displacement vector field was assessed via the Jacobian determinant (JAC). The post-registration alignments of rectums for 21 patients were visually assessed. The greatest improvement in the median DSC relative to the rigid registration result was 35 % for the Horn-Schunck algorithm with image processing. This algorithm also provided the best ASD results. The VelocityAI algorithms provided superior HD, MI, MSE and JAC results. The visual assessment indicated that the rigid plus deformable multi-pass method within VelocityAI resulted in the best rectum alignment. The DSC, ASD and HD improved significantly relative to the rigid registration result if image processing was applied prior

  19. Radiotherapeutic management and results of T1N0, T2N0 carcinoma of the oral tongue: Evaluation of boost techniques

    International Nuclear Information System (INIS)

    This paper presents the total experience of radiation therapy of early carcinoma of the oral tongue at the Massachusetts General Hospital over a span of 25 years. External beam radiotherapy with various boost techniques were used including interstitial implant, and intra-oral cone (IOC) using kilovoltage (250 kV HVL 1.53 mm Cu) radiations or low megavoltage electron beam. We evaluated our results of boost techniques for treatment of patients with T1N0 and T2N0 lesions and determined the 5-year actuarial local control rates of these treatment methods. From 1960-1978, 49 patients were treated by implant and 20 by intra-oral cone kilovoltage radiation. From 1979-1985, 73 patients were treated by intra-oral cone electron beam with minimal follow-up of 2 years. The 5-year actuarial local control rates for T1N0 and T2N0 lesions showed 54% after implant, 50% after intra-oral cone kilovoltage, and 86% after intra-oral cone electron beam boost with a p value of 0.0001. For the T1N0 lesions, the corresponding rates were 77%, 62%, and 90%, and for T2N0 lesions the rates were 54%, 43%, and 85%, respectively. In the absence of a prospective randomized trial, direct comparison of various boost techniques is not possible due to selection factor for therapy, increased clinical and technical expertise, and improvement in equipment. Therefore, no definitive conclusions can be made regarding optimum boost therapy. The data presented herein suggest that intra-oral cone electron beam boost technique is superior to interstitial implant for boosting early carcinoma of the tongue

  20. Design Specifications for a Radiation Tolerant Beam Loss Measurement ASIC

    CERN Document Server

    Venturini, G G; Effinger, E; Zamantzas, C

    2009-01-01

    A novel radiation-hardened current digitizer ASIC is in planning stage, aimed at the acquisition of the current signals from the ionization chambers employed in the Beam Loss Monitoring system at CERN. The purpose is to match and exceed the performance of the existing discrete component design, currently in operation in the Large Hadron Collider (LHC). The specifications include: a dynamic range of nine decades, defaulting to the 1 pA-1mA range but adjustable by the user, ability to withstand a total integrated dose of 10 kGy at least in 20 years of operation and user selectable integrating windows, as low as 500 ns. Moreover, the integrated circuit should be able to digitize currents of both polarity with a minimum number of external components and without needing any configuration. The target technology is the IBM 130nm CMOS process. The specifications, the architecture choices and the reasons on which they are based upon are discussed in this paper.

  1. Guiding of Laser Beams in Plasmas by Radiation Cascade Compression

    International Nuclear Information System (INIS)

    The near-resonant heatwave excitation of an electron plasma wave (EPW) can be employed for generating trains of few-fs electromagnetic pulses in rarefied plasmas. The EPW produces a co-moving index grating that induces a laser phase modulation at the beat frequency. Consequently, the cascade of sidebands red- and blue-shifted from the fundamental by integer multiples of the beat frequency is generated in the laser spectrum. When the beat frequency is lower than the electron plasma frequency, the phase chirp enables laser beatnote compression by the group velocity dispersion [S. Kalmykov and G. Shvets, Phys. Rev. E 73, 046403 (2006)]. In the 3D cylindrical geometry, the frequency-downshifted EPW not only modulates the laser frequency, but also causes the pulse to self-focus [P. Gibbon, Phys. Fluids B 2, 2196 (1990)]. After self-focusing, the multi-frequency laser beam inevitably diverges. Remarkably, the longitudinal beatnote compression can compensate the intensity drop due to diffraction. A train of high-intensity radiation spikes with continually evolving longitudinal profile can be self-guided over several Rayleigh lengths in homogeneous plasmas. High amplitude of the EPW is maintained over the entire propagation length. Numerical experiments on the electron acceleration in the cascade-driven (cascade-guided) EPW [using the code WAKE by P. Mora and T. M. Antonsen Jr., Phys. Plasmas 4, 217 (1997)] show that achieving GeV electron energy is possible under realistic experimental parameters

  2. Characterization of scatter radiation in cone beam CT mammography

    Science.gov (United States)

    Liu, Bob; Glick, Stephen J.; Groiselle, Corinne

    2005-04-01

    Cone beam CT mammography (CBCTM) is an emerging breast imaging technology and is currently under intensive investigation [1-3]. One of the major challenges in CBCTM is to understand the characteristics of scatter radiation and to find ways to reduce or correct its degrading effects. Since the breast shape, geometry and image formation process are significantly different from conventional mammography, all system components and parameters such as target/filter combination, kVp range, source to image distance, detector design etc. should be examined and optimized. In optimizing CBCTM systems, it is important to have knowledge of how different imaging parameters affect the recorded scatter within the image. In this study, a GEANT4 based Monte Carlo simulation package (GATE) was used to investigate the scatter magnitude and its" distribution in CBCTM. The influences of different air gaps, kVp settings, breast sizes and breast composition on the scatter primary ratio (SPR) and scatter profiles were examined. In general, the scatter to primary ratio (SPR) is strongly dependent on the breast size and air gap, and is only moderately dependent on the kVp setting and breast composition. These results may be used for optimization of CBCTM systems, as well as for developing scatter correction methods.

  3. Assessment of the environment using synchrotron radiation micro-beams

    International Nuclear Information System (INIS)

    The pollution from heavy metals such as lead and mercury has been a matter of great concern for decades as they may cause adverse health to human. In this study, we analyzed major and trace elements in modern and prehistoric teeth by X-ray fluorescence (XRF) analysis using synchrotron radiation micro-beams, in order to assess the changes of the environment through the civilization and the industrialization and their effects on human. Teeth from various periods of time including teeth from the human remains of the Jomon period were collected for the analysis as teeth are suggested to be indicators of the environmental changes. The main elements analyzed were Pb, Hg, Cu, and Zinc. Levels of Pb in modern teeth were higher than those in the Jomon teeth which indicate that the pollution from Pb is now greater than it was in the remote past. However, as there are small numbers of teeth collected in this study, there is a need to analyze more samples from various periods of time in order to assess the change of the environment in details

  4. Application of the Reduction of Scale Range in a Lorentz Boosted Frame to the Numerical Simulation of Particle Acceleration Devices

    International Nuclear Information System (INIS)

    It has been shown (1) that it may be computationally advantageous to perform computer simulations in a boosted frame for a certain class of systems: particle beams interacting with electron clouds, free electron lasers, and laser-plasma accelerators. However, even if the computer model relies on a covariant set of equations, it was also pointed out that algorithmic difficulties related to discretization errors may have to be overcome in order to take full advantage of the potential speedup (2) . In this paper, we focus on the analysis of the complication of data input and output in a Lorentz boosted frame simulation, and describe the procedures that were implemented in the simulation code Warp(3). We present our most recent progress in the modeling of laser wakefield acceleration in a boosted frame, and describe briefly the potential benefits of calculating in a boosted frame for the modeling of coherent synchrotron radiation.

  5. Off-axial acoustic radiation force of repulsor and tractor bessel beams on a sphere.

    Science.gov (United States)

    Silva, Glauber T; Lopes, J Henrique; Mitri, Farid G

    2013-06-01

    Acoustic Bessel beams are known to produce an axial radiation force on a sphere centered on the beam axis (on-axial configuration) that exhibits both repulsor and tractor behaviors. The repulsor and the tractor forces are oriented along the beam's direction of propagation and opposite to it, respectively. The behavior of the acoustic radiation force generated by Bessel beams when the sphere lies outside the beam's axis (off-axial configuration) is unknown. Using the 3-D radiation force formulas given in terms of the partial wave expansion coefficients for the incident and scattered waves, both axial and transverse components of the force exerted on a silicone- oil sphere are obtained for a zero- and a first-order Bessel vortex beam. As the sphere departs from the beam's axis, the tractor force becomes weaker. Moreover, the behavior of the transverse radiation force field may vary with the sphere's size factor ka (where k is the wavenumber and a is the sphere radius). Both stable and unstable equilibrium regions around the beam's axis are found, depending on ka values. These results are particularly important for the design of acoustical tractor beam devices operating with Bessel beams. PMID:25004483

  6. Aspects on the optimal photon beam energy for radiation therapy

    International Nuclear Information System (INIS)

    The selection of optimal photon beam energy is investigated both for realistic clinical bremsstrahlung beams and for monoenergetic photon beams. The photon energies covered in this investigation range from 60Co to bremsstrahlung and monoenergetic beams with maximum energies up to 50 MeV. One head and neck tumor and an advanced cervix tumor are investigated and the influence of beam direction is considered. It is shown that the use of optimized intensity modulated photon beams significantly reduces the need of beam energy selection. The most suitable single accelerator potential will generally be in the range 6-15 MV for both superficially located and deep-seated targets, provided intensity-modulated dose delivery is employed. It is also shown that a narrow penumbra region of a photon beam ideally should contain low-energy photons (≤4 MV), whereas the gross tumor volume, particularly when deep-seated targets are concerned, should be irradiated by high-energy photons. The regions where low photon energies are most beneficial are where organs at risk are laterally close to the target volume. The situation is completely changed when uniform or wedged beams are used. The selection of optimal beam energy then becomes a very important task in line with the experience from traditional treatment techniques. However, even with a large number of uniform beam portals, the treatment outcome is substantially lower than with a few optimized intensity-modulated beams. (orig.)

  7. Development of modulated electron beam for intensity modulated radiation therapy (IMRT) on a photocathode electron gun

    International Nuclear Information System (INIS)

    Radiation therapy of cancer is developing to un-uniform irradiation, for concentrating dose to a cancer tumor and reducing dose to normal tissue. As a step toward the Intensity modulated radiation therapy, we examined dynamic optical modulation of electron beam produced by a photocathode electron gun. Images on photo-masks were transferred onto a photocathode by relay imaging. Electron beam could be controlled by a remote mirror. Modulated electron beam maintained its shape on acceleration, had a fine spatial resolution, and could be moved dynamically by optical methods. As a second step, optical modulation of electron beam and dynamic control succeeded by a digital micro mirror device (DMD). (author)

  8. EFFECT OF ELECTRON BEAM RADIATIONS ON ANXIETY IN EXPERIMENTAL ANIMAL MODELS

    OpenAIRE

    Deepa B; Shyamjith Manikkoth

    2015-01-01

    Objectives: The aim of the study was to test the effect of whole body electron beam radiation on anxiety statein Swiss albino mice. Methods: Mice were irradiated with three different doses (2Gy,4Gy,6Gy)of electron beam radiations.After 24hours of radiation exposure animals were taken for testing level of anxiety using elevated plus maze and light dark arena apparatus. Results: Whole body electron beam irradiation at doses of 2, 4 and 6Gy lead to significant (p

  9. Experimental study of acoustic radiation force of an ultrasound beam on absorbing and scattering objects

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaeva, Anastasiia V., E-mail: niko200707@mail.ru; Kryzhanovsky, Maxim A.; Tsysar, Sergey A. [Department of Acoustics, Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Kreider, Wayne [Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th St. Seattle WA 98105 (United States); Sapozhnikov, Oleg A. [Department of Acoustics, Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991 (Russian Federation); Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th St. Seattle WA 98105 (United States)

    2015-10-28

    Acoustic radiation force is a nonlinear acoustic effect caused by the transfer of wave momentum to absorbing or scattering objects. This phenomenon is exploited in modern ultrasound metrology for measurement of the acoustic power radiated by a source and is used for both therapeutic and diagnostic sources in medical applications. To calculate radiation force an acoustic hologram can be used in conjunction with analytical expressions based on the angular spectrum of the measured field. The results of an experimental investigation of radiation forces in two different cases are presented in this paper. In one case, the radiation force of an obliquely incident ultrasound beam on a large absorber (which completely absorbs the beam) is considered. The second case concerns measurement of the radiation force on a spherical target that is small compared to the beam diameter.

  10. Experimental study of acoustic radiation force of an ultrasound beam on absorbing and scattering objects

    International Nuclear Information System (INIS)

    Acoustic radiation force is a nonlinear acoustic effect caused by the transfer of wave momentum to absorbing or scattering objects. This phenomenon is exploited in modern ultrasound metrology for measurement of the acoustic power radiated by a source and is used for both therapeutic and diagnostic sources in medical applications. To calculate radiation force an acoustic hologram can be used in conjunction with analytical expressions based on the angular spectrum of the measured field. The results of an experimental investigation of radiation forces in two different cases are presented in this paper. In one case, the radiation force of an obliquely incident ultrasound beam on a large absorber (which completely absorbs the beam) is considered. The second case concerns measurement of the radiation force on a spherical target that is small compared to the beam diameter

  11. Radiation safety aspects of the operation of first three synchrotron beam lines of Indus-2.

    Science.gov (United States)

    Nayak, M K; Nair, Haridas G; Bakshi, A K; Sahani, P K; Singh, Sunil; Khan, Saleem; Verma, Dimple; Dev, Vipin; Sahu, T K; Khare, Mukesh; Kumar, Vijay; Bandyopadhyay, Tapas; Tripathi, R M; Sharma, D N

    2015-04-01

    Five synchrotron radiation beam lines are commissioned and now under regular operation at the Synchrotron Radiation Source, Indus-2 at Raja Ramanna Centre For Advanced Technology (RRCAT), Indore, India. Nine beam lines are under trial operation, and six beam lines are in the installation stage. In the early phase of installation of beam lines on Indus-2, three bending magnet beam lines, Extended X-ray Absorption Fine Structure (EXAFS, BL-8), Energy Dispersive X-ray Diffraction (EDXRD, BL-11) and Angle Dispersive X-ray Diffraction (ADXRD, BL-12), were installed and commissioned, after approval from Atomic Energy Regulatory Board (AERB), India. These beam lines are pink (BL-8), white (BL-11) and monochromatic (BL-12), which are housed in specially designed shielded hutches. In order to ensure safety of users and other working personnel from ionizing radiations present in these beam lines, several safety systems are incorporated and safety procedures are followed. The paper describes the radiological safety aspects of the three beam lines during its initial commissioning trials and also the measurements on radiation levels carried out in and around the beam line hutches. PMID:25209995

  12. Cone beam computed tomography radiation dose and image quality assessments.

    Science.gov (United States)

    Lofthag-Hansen, Sara

    2010-01-01

    Diagnostic radiology has undergone profound changes in the last 30 years. New technologies are available to the dental field, cone beam computed tomography (CBCT) as one of the most important. CBCT is a catch-all term for a technology comprising a variety of machines differing in many respects: patient positioning, volume size (FOV), radiation quality, image capturing and reconstruction, image resolution and radiation dose. When new technology is introduced one must make sure that diagnostic accuracy is better or at least as good as the one it can be expected to replace. The CBCT brand tested was two versions of Accuitomo (Morita, Japan): 3D Accuitomo with an image intensifier as detector, FOV 3 cm x 4 cm and 3D Accuitomo FPD with a flat panel detector, FOVs 4 cm x 4 cm and 6 cm x 6 cm. The 3D Accuitomo was compared with intra-oral radiography for endodontic diagnosis in 35 patients with 46 teeth analyzed, of which 41 were endodontically treated. Three observers assessed the images by consensus. The result showed that CBCT imaging was superior with a higher number of teeth diagnosed with periapical lesions (42 vs 32 teeth). When evaluating 3D Accuitomo examinations in the posterior mandible in 30 patients, visibility of marginal bone crest and mandibular canal, important anatomic structures for implant planning, was high with good observer agreement among seven observers. Radiographic techniques have to be evaluated concerning radiation dose, which requires well-defined and easy-to-use methods. Two methods: CT dose index (CTDI), prevailing method for CT units, and dose-area product (DAP) were evaluated for calculating effective dose (E) for both units. An asymmetric dose distribution was revealed when a clinical situation was simulated. Hence, the CTDI method was not applicable for these units with small FOVs. Based on DAP values from 90 patient examinations effective dose was estimated for three diagnostic tasks: implant planning in posterior mandible and

  13. Electron beam characterizations with optical diffraction radiation from circular aperture and rectangular slit

    International Nuclear Information System (INIS)

    Diffraction radiation (DR) is one of the most promising candidates for electron beam diagnostics for the high-energy accelerator facilities due to non-intercepting, multi-parameter and real-time capabilities. In this paper we investigated the possibility of using DR from circular aperture target to characterize electron beam parameters. The method to separate beam's divergence and beam size with two wavelengths components is discussed. A new method suitable for small beam size determination with DR from rectangular slit by scanning the slit in transverse direction is proposed

  14. Beam characteristics of mixed gamma-neutron radiation from IBR 30 reactor

    International Nuclear Information System (INIS)

    Measurements were carried out in the pulsed fast reactor IBR-30 experimental channels aimed at verifying the properties of different types of detectors in the mixed gamma-neutron field and obtaining information on neutron beam, such as the neutron beam homogeneity, thermal neutron fluence, neutron beam dosimetric characteristic and the relative proportion of gamma rays in the mixed gamma and neutron radiation. The information on gamma radiation and thermal neutron fluence were obtained using different thermoluminescent materials. Several solid state track detectors were used as fast neutron dosemeters. The results show that the properties of the detectors described permit their application in finding the characteristics of the individual components of mixed neutron and gamma radiation fields. It was found that the neutron component prevailed in the IBR-30 reactor neutron beam and that the beam was homogeneous along the entire channel cross section. (J.B.)

  15. Radiation processing of Nylon 6 by e-beam for improved properties and performance

    International Nuclear Information System (INIS)

    Percent water absorption of Nylon 6 was reduced substantially when irradiated by e-beam radiation in presence of triallyl isocyanurate. Hardness, tensile strength, flexural strength, and impact resistance of Nylon 6 were also improved with the dose of e-beam radiation. Improvement of mechanical properties and reduction of water absorption were due to the cross-linking of polyamide molecules in the presence of high-energy radiation. Increase of cross-linking with increasing radiation dose was verified by the increase of gel content at higher doses

  16. Long-Term Follow-Up of Preoperative Pelvic Radiation Therapy and Concomitant Boost Irradiation in Locally Advanced Rectal Cancer Patients: A Multi-Institutional Phase II Study (KROG 04-01)

    International Nuclear Information System (INIS)

    Purpose: To perform a prospective phase II study to investigate the efficacy and safety of preoperative pelvic radiation therapy and concomitant small-field boost irradiation with 5-fluorouracil and leucovorin for 5 weeks in locally advanced rectal cancer patients. Methods and Materials: Sixty-nine patients with locally advanced, nonmetastatic, mid-to-lower rectal cancer were prospectively enrolled. They had received preoperative chemoradiation therapy and total mesorectal excision. Pelvic radiation therapy of 43.2 Gy in 24 fractions plus concomitant boost radiation therapy of 7.2 Gy in 12 fractions was delivered to the pelvis and tumor bed for 5 weeks. Two cycles of 5-fluorouracil and leucovorin were administered for 3 days in the first and fifth week of radiation therapy. The pathologic response, survival outcome, and treatment toxicity were evaluated for the study endpoints. Results: Of 69 patients, 8 (11.6%) had a pathologically complete response. Downstaging rates were 40.5% for T classification and 68.1% for N classification. At the median follow-up of 69 months, 36 patients have been followed up for more than 5 years. The 5-year disease-free survival (DFS) and overall survival rates were 66.0% and 75.3%, respectively. Higher pathologic T (P = .045) and N (P = .032) classification were significant adverse prognostic factors for DFS, and high-grade histology was an adverse prognostic factor for both DFS (P = .025) and overall survival (P = .031) on the multivariate analysis. Fifteen patients (21.7%) experienced grade 3 or 4 acute toxicity, and 7 patients (10.1%) had long-term toxicity. Conclusion: Preoperative pelvic radiation therapy with concomitant boost irradiation with 5-fluorouracil and leucovorin for 5 weeks showed acceptable acute and long-term toxicities. However, the benefit of concomitant small-field boost irradiation for 5 weeks in rectal cancer patients was not demonstrated beyond conventional irradiation for 6 weeks in terms of tumor response and

  17. Long-Term Follow-Up of Preoperative Pelvic Radiation Therapy and Concomitant Boost Irradiation in Locally Advanced Rectal Cancer Patients: A Multi-Institutional Phase II Study (KROG 04-01)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Hoon [Department of Radiation Oncology, Seoul St. Mary' s Hospital, College of Medicine, Catholic University of Korea, Seoul (Korea, Republic of); Department of Radiation Oncology, St. Vincent' s Hospital, Catholic University of Korea, Suwon (Korea, Republic of); Kim, Dae Yong [Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Go-Yang (Korea, Republic of); Nam, Taek-Keun [Department of Radiation Oncology, Chonnam National University Hospital, Hwa-Sun (Korea, Republic of); Yoon, Sei-Chul [Department of Radiation Oncology, Seoul St. Mary' s Hospital, College of Medicine, Catholic University of Korea, Seoul (Korea, Republic of); Lee, Doo Seok [Department of Colorectal Surgery, Daehang Hospital, Seoul (Korea, Republic of); Park, Ji Won; Oh, Jae Hwan; Chang, Hee Jin [Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Go-Yang (Korea, Republic of); Yoon, Mee Sun; Jeong, Jae-Uk [Department of Radiation Oncology, Chonnam National University Hospital, Hwa-Sun (Korea, Republic of); Jang, Hong Seok, E-mail: hsjang11@catholic.ac.kr [Department of Radiation Oncology, Seoul St. Mary' s Hospital, College of Medicine, Catholic University of Korea, Seoul (Korea, Republic of)

    2012-11-15

    Purpose: To perform a prospective phase II study to investigate the efficacy and safety of preoperative pelvic radiation therapy and concomitant small-field boost irradiation with 5-fluorouracil and leucovorin for 5 weeks in locally advanced rectal cancer patients. Methods and Materials: Sixty-nine patients with locally advanced, nonmetastatic, mid-to-lower rectal cancer were prospectively enrolled. They had received preoperative chemoradiation therapy and total mesorectal excision. Pelvic radiation therapy of 43.2 Gy in 24 fractions plus concomitant boost radiation therapy of 7.2 Gy in 12 fractions was delivered to the pelvis and tumor bed for 5 weeks. Two cycles of 5-fluorouracil and leucovorin were administered for 3 days in the first and fifth week of radiation therapy. The pathologic response, survival outcome, and treatment toxicity were evaluated for the study endpoints. Results: Of 69 patients, 8 (11.6%) had a pathologically complete response. Downstaging rates were 40.5% for T classification and 68.1% for N classification. At the median follow-up of 69 months, 36 patients have been followed up for more than 5 years. The 5-year disease-free survival (DFS) and overall survival rates were 66.0% and 75.3%, respectively. Higher pathologic T (P = .045) and N (P = .032) classification were significant adverse prognostic factors for DFS, and high-grade histology was an adverse prognostic factor for both DFS (P = .025) and overall survival (P = .031) on the multivariate analysis. Fifteen patients (21.7%) experienced grade 3 or 4 acute toxicity, and 7 patients (10.1%) had long-term toxicity. Conclusion: Preoperative pelvic radiation therapy with concomitant boost irradiation with 5-fluorouracil and leucovorin for 5 weeks showed acceptable acute and long-term toxicities. However, the benefit of concomitant small-field boost irradiation for 5 weeks in rectal cancer patients was not demonstrated beyond conventional irradiation for 6 weeks in terms of tumor response and

  18. LCLS Spontaneous Radiation with Reflection along the Beam Line in the Undulator Pipes

    Energy Technology Data Exchange (ETDEWEB)

    2010-12-07

    Monte Carlo simulations of the spontaneous radiation at low and high energies up to the Near Experimental Hall entrance yield beam widths for use in the design of transport and diagnostic instruments in the Front End Enclosure.

  19. Theoretical and experimental study of an energy-reinforced braking radiation photon beam

    International Nuclear Information System (INIS)

    This research thesis reports the theoretical study of a photon beam raised towards high energies, its experimental implementation, the definition of a gamma spectrometry method which aimed at checking various hypotheses used in the beam theoretical study. After a presentation of the theory of phenomena of electron braking radiation, of materialisation of photons into positon-negaton pair, and of issues related to multiple Coulomb diffusion, the author reports the study of the different solutions which allow a photon beam to be obtained. A braking radiation of mono-kinetic electron has been used. This braking radiation is reinforced by absorption of low energy protons in a column of lithium hydride. The author describes how the beam is built up, and the experimental approach. He describes how raw data are processed to get rid of the influence of the multiple Coulomb diffusion and of the braking radiation. Experimental results are compared with those obtained by convolution of photon spectra and differential cross section

  20. Optical Transition Radiation Measurement of Electron Beam for Beijing Free Electron Laser

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qiang; XIE Jia-Lin; LI Yong-Gui; ZHUANG Jie-Jia

    2001-01-01

    We used transition radiation techniques instead of the original phosphor targets to improve the electronic beam diagnostic system at Beijing Free Electron Laser. The beam profile, size (3.3 × 2.4 mm), position and divergence angle (σrms = 2.5 mrad) in transverse have been obtained from optical transition radiation. We also present the experimental set-up and some preliminary results.

  1. Electron beam radiation induced oxidative stress on alteration of enzymatic antioxidant status of Swiss albino mice

    International Nuclear Information System (INIS)

    Ionizing radiation causes damage to living tissues through a series of molecular events, such as photoelectric, Compton and Auger effects, depending on the radiation energy. Because human tissues contain 80% water, the major radiation damage is due to the aqueous free radicals, generated by the action of radiation on water. It was found to be 10 Gy was the lethal dose for mice. Different dosages (4 Gy, 6 Gy and 8 Gy) of electron beam radiation were used to study the level of lipid peroxidation and enzymatic antioxidant status of irradiated mice. The results showed higher the radiation dosage, increased lipid peroxidation and decreased antioxidant level. (author)

  2. Possibilities of optical transition radiation using for the U-70 and the UNR proton beam diagnostics

    International Nuclear Information System (INIS)

    Experimental results for optical transition radiation (OTR) of 70 GeV protons have been obtained. A possibility of the proton beam diagnostics using this raiation and the digital television method is illustrated. It is shown that thin aluminium fail doesn't perturb the proton beam and the conditions for using OTR for beam monitoring improve with proton energy. 15 refs.; 14 figs.; 1 tab

  3. Control of the beam-internal target interaction at the Nuclotron by means of light radiation

    International Nuclear Information System (INIS)

    The light radiation from various internal targets at the Nuclotron can be utilized for the operative control and time optimization of the interaction intensity of the beam. The examples presented in the paper illustrate the information about space characteristics of the circulating beam during one cycle of the accelerator run at the stages of injection, acceleration and during the physical experiments. (author)

  4. Coherent undulator radiation of electron beam, microbunched for the FEL power outcoupling

    Energy Technology Data Exchange (ETDEWEB)

    Kulipanov, G.N.; Sokolov, A.S.; Vinokurov, N.A. [Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation)

    1995-12-31

    The spectral intensity of the coherent undulator radiation of electron beam, preliminarily microbunched by the FEL oscillator for the FEL power outcoupling, is approximately calculated by simple analytic considerations, taking into account the transverse emittances and the energy spread of the microbunched electron beams.

  5. Microdosimetric measurements of radiation quality variations in homogeneous phantoms irradiated by fast neutron beams

    International Nuclear Information System (INIS)

    The Dual Radiation Action Theory of Kellerer and Rossi (DRA), along with presently available microdosimetric techniques, is applied to the detrmination of radiation quality variation within tissue equivalent phantoms irradiated by collimated fast neutron beams. The neutron beams investigated were produced by the bombardment of 22.5 and 16 MeV d+ on beryllium and by the T(d,n)4He reaction (15-MeV neutrons). Microdosimetric spectra were obtained at points of varying depth and lateral distance from the central axis within a tissue equivalent phantom, including points within the penumbra. From the microdosimetric spectra the parameter RQ, a first approximation to RBE derived from DRA theory, is calculated for each point. All RQ values are calculated for the same level of effect. For these three different beams the results show that the RQ values for the total radiation spectrum of neutron and gamma radiation remain fairly constant with depth and with lateral distance from the beam axis at 2 and 10 cm depths. The largest central axis variation in RQ is 8% for the d(16)+Be beam. The largest variation between a penumbra and an on-axis RQ value is 4% at 2 cm depth in the d(22.5)+Be beam. The results for the d(22.5)+Be beam disagree with previously reported radiobiological results while the 15 MeV beam results are in good agreement

  6. Microdosimetric measurements of radiation quality variations in homogeneous phantoms irradiated by fast neutron beams

    International Nuclear Information System (INIS)

    The Dual Radiation Action Theory of Kellerer and Rossi (DRA), along with presently available microdosimetric techniques, is applied to the determination of radiation quality variation within tissue equivalent phantoms irradiated by collimated fast neutron beams. The neutron beams investigated were produced by the bombardment of 22.5 and 16 MeV d + on beryllium and by the T(d,n)4He reaction (15-MeV neutrons). Microdosimetric spectra were obtained at points of varying depth and lateral distance from the central axis within a tissue equivalent phantom, including points within the penumbra. From the microdosimetric spectra the parameter RQ, a first approximation to RBE derived from DRA theory, is calculated for each point. All RQ values are calculated for the same level of effect. For these three different beams the results show that the RQ values for the total radiation spectrum of neutron and gamma radiation remain fairly constant with depth and with lateral distance from the beam axis at 2 and 10 cm depths. The largest central axis variation in RQ is 8% for the d(16) + Be beam. The largest variation between a penumbra and an on-axis RQ value is 4% at 2 cm depth in the d(22.5) + Be beam. The results for the d (22.5) + Be beam disagree with previously reported radiological results while the 15 McV beam results are in good agreement

  7. Characterization and application of two extrapolation chambers in standard X radiation beams

    International Nuclear Information System (INIS)

    The extrapolation chambers are ionization chambers with variable volume, and they are mainly utilized as beta radiation detectors. In this work two extrapolation chambers were characterized, a commercial PTW extrapolation chamber and another extrapolation chamber developed at the Calibration Laboratory of IPEN, for application as reference systems in mammography, conventional diagnostic radiology and radiotherapy beams. The results obtained from the characterization tests of the chamber response: leakage current, short- and medium terms stability, determination of the saturation currents and the ion collection efficiencies, angular and energy dependence, show that these extrapolation chambers may be utilized for low-energy X radiation beam dosimetry. The transmission factors in tissue and the calibration factors were also determined for all cited radiation qualities. Finally, a procedure was established for calibration of radiation detectors in standard X radiation beams, using the extrapolation chambers. (author)

  8. A novel approach in electron beam radiation therapy of lips carcinoma: A Monte Carlo study

    Energy Technology Data Exchange (ETDEWEB)

    Shokrani, Parvaneh [Medical Physics and Medical Engineering Department, School of Medicine, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Baradaran-Ghahfarokhi, Milad [Medical Physics and Medical Engineering Department, School of Medicine, Isfahan University of Medical Sciences, Isfahan 81746-73461, Iran and Medical Radiation Engineering Department, Faculty of Advanced Sciences and Technologies, Isfahan University, Isfahan 81746-73441 (Iran, Islamic Republic of); Zadeh, Maryam Khorami [Medical Physics Department, School of Medicine, Ahwaz Jundishapour University of Medical Sciences, Ahwaz 15794-61357 (Iran, Islamic Republic of)

    2013-04-15

    Purpose: Squamous cell carcinoma (SCC) is commonly treated by electron beam radiotherapy (EBRT) followed by a boost via brachytherapy. Considering the limitations associated with brachytherapy, in this study, a novel boosting technique in EBRT of lip carcinoma using an internal shield as an internal dose enhancer tool (IDET) was evaluated. An IDET is referred to a partially covered internal shield located behind the lip. It was intended to show that while the backscattered electrons are absorbed in the portion covered with a low atomic number material, they will enhance the target dose in the uncovered area. Methods: Monte-Carlo models of 6 and 8 MeV electron beams were developed using BEAMnrc code and were validated against experimental measurements. Using the developed models, dose distributions in a lip phantom were calculated and the effect of an IDET on target dose enhancement was evaluated. Typical lip thicknesses of 1.5 and 2.0 cm were considered. A 5 Multiplication-Sign 5 cm{sup 2} of lead covered by 0.5 cm of polystyrene was used as an internal shield, while a 4 Multiplication-Sign 4 cm{sup 2} uncovered area of the shield was used as the dose enhancer. Results: Using the IDET, the maximum dose enhancement as a percentage of dose at d{sub max} of the unshielded field was 157.6% and 136.1% for 6 and 8 MeV beams, respectively. The best outcome was achieved for lip thickness of 1.5 cm and target thickness of less than 0.8 cm. For lateral dose coverage of planning target volume, the 80% isodose curve at the lip-IDET interface showed a 1.2 cm expansion, compared to the unshielded field. Conclusions: This study showed that a boost concomitant EBRT of lip is possible by modifying an internal shield into an IDET. This boosting method is especially applicable to cases in which brachytherapy faces limitations, such as small thicknesses of lips and targets located at the buccal surface of the lip.

  9. A novel approach in electron beam radiation therapy of lips carcinoma: A Monte Carlo study

    International Nuclear Information System (INIS)

    Purpose: Squamous cell carcinoma (SCC) is commonly treated by electron beam radiotherapy (EBRT) followed by a boost via brachytherapy. Considering the limitations associated with brachytherapy, in this study, a novel boosting technique in EBRT of lip carcinoma using an internal shield as an internal dose enhancer tool (IDET) was evaluated. An IDET is referred to a partially covered internal shield located behind the lip. It was intended to show that while the backscattered electrons are absorbed in the portion covered with a low atomic number material, they will enhance the target dose in the uncovered area. Methods: Monte-Carlo models of 6 and 8 MeV electron beams were developed using BEAMnrc code and were validated against experimental measurements. Using the developed models, dose distributions in a lip phantom were calculated and the effect of an IDET on target dose enhancement was evaluated. Typical lip thicknesses of 1.5 and 2.0 cm were considered. A 5 × 5 cm2 of lead covered by 0.5 cm of polystyrene was used as an internal shield, while a 4 × 4 cm2 uncovered area of the shield was used as the dose enhancer. Results: Using the IDET, the maximum dose enhancement as a percentage of dose at dmax of the unshielded field was 157.6% and 136.1% for 6 and 8 MeV beams, respectively. The best outcome was achieved for lip thickness of 1.5 cm and target thickness of less than 0.8 cm. For lateral dose coverage of planning target volume, the 80% isodose curve at the lip-IDET interface showed a 1.2 cm expansion, compared to the unshielded field. Conclusions: This study showed that a boost concomitant EBRT of lip is possible by modifying an internal shield into an IDET. This boosting method is especially applicable to cases in which brachytherapy faces limitations, such as small thicknesses of lips and targets located at the buccal surface of the lip.

  10. Boosting foundations and algorithms

    CERN Document Server

    Schapire, Robert E

    2012-01-01

    Boosting is an approach to machine learning based on the idea of creating a highly accurate predictor by combining many weak and inaccurate "rules of thumb." A remarkably rich theory has evolved around boosting, with connections to a range of topics, including statistics, game theory, convex optimization, and information geometry. Boosting algorithms have also enjoyed practical success in such fields as biology, vision, and speech processing. At various times in its history, boosting has been perceived as mysterious, controversial, even paradoxical.

  11. The impact of MLC transmitted radiation on EPID dosimetry for dynamic MLC beams

    International Nuclear Information System (INIS)

    The purpose of this study was to experimentally quantify the change in response of an amorphous silicon (a-Si) electronic portal imaging device (EPID) to dynamic multileaf collimator (dMLC) beams with varying MLC-transmitted dose components and incorporate the response into a commercial treatment planning system (TPS) EPID prediction model. A combination of uniform intensity dMLC beams and static beams were designed to quantify the effect of MLC transmission on EPID response at the central axis of 10x10 cm2 beams, at off-axis positions using wide dMLC beam profiles, and at different field sizes. The EPID response to MLC transmitted radiation was 0.79±0.02 of the response to open beam radiation at the central axis of a 10x10 cm2 field. The EPID response to MLC transmitted radiation was further reduced relative to the open beam response with off-axis distance. The EPID response was more sensitive to field size changes for MLC transmitted radiation compared to open beam radiation by a factor of up to 1.17 at large field sizes. The results were used to create EPID response correction factors as a function of the fraction of MLC transmitted radiation, off-axis distance, and field size. Software was developed to apply the correction factors to each pixel in the TPS predicted EPID image. The corrected images agreed more closely with the measured EPID images in areas of intensity modulated fields with a large fraction of MLC transmission and, as a result the accuracy of portal dosimetry with a-Si EPIDs can be improved. Further investigation into the detector response function and the radiation source model are required to achieve improvements in accuracy for the general case

  12. Oncologic and functional outcome of base of tongue cancer treated with external-beam radiation and I-192 implant

    International Nuclear Information System (INIS)

    This paper assesses tumor control and functional outcome for squamous cancer of the base of the tongue managed with external irradiation plus Ir-192 implant. Between January 1981 and June 1990, 36 previously untreated patients were treated with 5,000-5,400 cGy of external-beam radiation plus a 2,000-3,000 cGy boost to the base of tongue with an Ir-192 implant. Negative necks were irradiated alone, and positive necks were treated with irradiation followed by neck dissection. Crude local control by T stage are as follows: T1, 10 of 11; T2, 13 of 14; T3, 8 of 10; and T4 1 of 1. Actuarial local control is 87.5%. Of the four local failures, two were salvaged by surgery. Neck control was achieved in 35 of 36 patients. Complications occurred in 25%. When implantation was done with the nonlooping technique, the injury rate was statistically higher than when done with the looping technique (6 of 12 = 50% vs 3 of 24 = 12.5%, P = .02)

  13. Radiation pressure cross section exerted on homogenous dielectric spherical particle by zeroth order Mathieu beams

    Science.gov (United States)

    Chafiq, A.; Belafhal, A.

    2016-08-01

    In this paper, we present a full calculation of radiation pressure cross section and optical forces exerted by linearly polarized zeroth order Mathieu beams on homogenous dielectric spherical particle in the framework of generalized Lorenz-Mie theory (GLMT). In this theory, the scattered fields are dependent upon the Mie scattering coefficients and the beam shape coefficients. So a new optical property such as force and torque appears by changing the beam profile and the nature of particle. In this way, this work is devoted to the analysis of both transverse and longitudinal optical forces exerted on a simple dielectric spherical particle by zeroth order Mathieu beams and zeroth order Bessel (which is a particular case of the first beam). Thus, through numerical simulations, we show that zeroth order Mathieu beams can't trap this particle but Bessel beam presents some dimensional stable equilibrium points.

  14. Summary report of working group 5: Beam and radiation generation, monitoring, and control

    CERN Document Server

    Church, Mike; 10.1063/1.3520295

    2012-01-01

    This paper summarizes the activities and presentations of Working Group 5 of the Advanced Accelerator Concepts Workshop held at Annapolis, Maryland in June 2010. Working Group 5 touched on a broad range of topics in the fields of beam and radiation generation and their monitoring and control. These topics were not comprehensively covered in this Workshop, but rather the Working Group concentrated on specific new developments and recent investigations. The Working Group divided its sessions into four broad categories: cathodes and electron guns, radiation generation, beam diagnostics, and beam control and dynamics. This summary is divided into the same structure.

  15. A Monitor and Control System for the Synchrotron Radiation Beam Lines at DAΦNE

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Three synchrotron radiation beam lines have been built on DAΦNE,the Frascati electron-positron accelerator.It is Possible to monitor and control all the elements on the beam lines using a modular network distributed I/O system by National Instrunments (FieldPoint) with Bridge VIEW/Lab VIEW programs,Two of these beam lines have radiation safety problems solved by two independent and redundant systems,using mechanical switches ,and S7-200 PLC's by Siemens.In this article our solution will be described in details.

  16. Summary report of working group 5: Beam and radiation generation, monitoring, and control

    International Nuclear Information System (INIS)

    This paper summarizes the activities and presentations of Working Group 5 of the Advanced Accelerator Concepts Workshop held at Annapolis, Maryland in June 2010. Working Group 5 touched on a broad range of topics in the fields of beam and radiation generation and their monitoring and control. These topics were not comprehensively covered in this Workshop, but rather the Working Group concentrated on specific new developments and recent investigations. The Working Group divided its sessions into four broad categories: cathodes and electron guns, radiation generation, beam diagnostics, and beam control and dynamics. This summary is divided into the same structure.

  17. Summary Report of Working Group 5: Beam and Radiation Generation, Monitoring, and Control

    International Nuclear Information System (INIS)

    This paper summarizes the activities and presentations of Working Group 5 of the Advanced Accelerator Concepts Workshop held at Annapolis, Maryland in June 2010. Working Group 5 touched on a broad range of topics in the fields of beam and radiation generation and their monitoring and control. These topics were not comprehensively covered in this Workshop, but rather the Working Group concentrated on specific new developments and recent investigations. The Working Group divided its sessions into four broad categories: cathodes and electron guns, radiation generation, beam diagnostics, and beam control and dynamics. This summary is divided into the same structure.

  18. 21 CFR 892.5710 - Radiation therapy beam-shaping block.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiation therapy beam-shaping block. 892.5710 Section 892.5710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Therapeutic Devices § 892.5710 Radiation therapy...

  19. Coherent and Tunable Terahertz Radiation from Graphene Surface Plasmon Polarirons Excited by Cyclotron Electron Beam

    Science.gov (United States)

    Zhao, Tao; Gong, Sen; Hu, Min; Zhong, Renbin; Liu, Diwei; Chen, Xiaoxing; Zhang, Ping; Wang, Xinran; Zhang, Chao; Wu, Peiheng; Liu, Shenggang

    2015-11-01

    Terahertz (THz) radiation can revolutionize modern science and technology. To this date, it remains big challenges to develop intense, coherent and tunable THz radiation sources that can cover the whole THz frequency region either by means of only electronics (both vacuum electronics and semiconductor electronics) or of only photonics (lasers, for example, quantum cascade laser). Here we present a mechanism which can overcome these difficulties in THz radiation generation. Due to the natural periodicity of 2π of both the circular cylindrical graphene structure and cyclotron electron beam (CEB), the surface plasmon polaritions (SPPs) dispersion can cross the light line of dielectric, making transformation of SPPs into radiation immediately possible. The dual natural periodicity also brings significant excellences to the excitation and the transformation. The fundamental and hybrid SPPs modes can be excited and transformed into radiation. The excited SPPs propagate along the cyclotron trajectory together with the beam and gain energy from the beam continuously. The radiation density is enhanced over 300 times, up to 105 W/cm2. The radiation frequency can be widely tuned by adjusting the beam energy or chemical potential. This mechanism opens a way for developing desired THz radiation sources to cover the whole THz frequency regime.

  20. Absolute and secondary dosimetry at the cyclotron ion beam radiation experiments

    International Nuclear Information System (INIS)

    One of the characteristic features of ion beam radiation experiments is that the absolute methods of dosimetry are more convenient than secondary ones. In this paper the absolute method used in the course of the radiation experiments performed on the U-400 Dubna cyclotron is presented in detail. Some remarks dealing with the secondary methods are also given. (author)

  1. Off-axial acoustic radiation force of pressor and tractor Bessel beams on a sphere

    CERN Document Server

    Silva, Glauber T; Lobo, Tiago P; Mitri, Farid G

    2012-01-01

    Acoustic Bessel beams are known to produce an axial radiation force on a sphere centered on the beam axis (on-axial configuration) that exhibits both "pressor" and "tractor" behaviors. The pressor and the tractor forces are oriented along the beam's direction of propagation and opposite to it, respectively. The behavior of the acoustic radiation force generated by Bessel beams when the sphere lies outside the beam's axis (off-axial configuration) is unknown. Using the 3D radiation force formulas given in terms of the partial wave expansion coefficients for the incident and scattered waves, both axial and transverse components of the force exerted on a silicone-oil sphere are obtained for a zero- and a first-order Bessel vortex beam. As the sphere departs from the beam's axis, the tractor force becomes weaker. Moreover, the behavior of the transverse radiation force field may vary with the sphere's size factor $ka$ (where $k$ is the wavenumber and $a$ is the sphere radius). Both stable and unstable equilibrium...

  2. Feasibility of optical diffraction radiation for a non-invasive low-emittance beam diagnostics

    CERN Document Server

    Urakawa, J; Kubo, K; Kuroda, S; Terunuma, N; Kuriki, M; Okugi, T; Naito, T; Araki, S; Potylitsin, A P; Naumenko, G A; Karataev, P; Potylitsyna, N A; Vnukov, I; Hirose, T; Hamatsu, R; Muto, T; Ikezawa, M; Shibata, Y

    2001-01-01

    A 'proof-of-principle' experiment on the optical diffraction radiation (ODR) as a single-pulse beam profile monitor is planned using an electron beam extracted from the KEK-ATF damping ring. The main goals of this experiment are the following: (i) To measure the yield and the angular distributions of the optical diffraction radiation from a large-size target at different wavelengths, impact parameters and beam characteristics for a comparison with analogous characteristics of optical transition radiation from a foil with identical optical parameters and for a verification of the model assumption (perfectly conducting semi-infinite target). (ii) To investigate the ODR angular distributions from a tilted target with a slit for observing the interference effects. (iii) To compare the results obtained by simulations based on classical approaches, taking into account the optical characteristics of the equipment and the beam parameters. (iv) To estimate the prospects of using ODR as a new non-invasive tool for ultr...

  3. Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures

    International Nuclear Information System (INIS)

    We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 MeV operation

  4. Measured radiation and background levels during transmission of megawatt electron beams through millimeter apertures

    International Nuclear Information System (INIS)

    We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 mev electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 mev operation

  5. Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures

    Energy Technology Data Exchange (ETDEWEB)

    Alarcon, Ricardo [Arizona State University, Glendale, AZ (United States); Balascuta, S. [Arizona State University, Glendale, AZ (United States); Benson, Stephen V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Bertozzi, William [Massachusetts Institute of Technology, Cambridge, MA (United States); Boyce, James R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Cowan, Ray [Massachusetts Institute of Technology, Cambridge, MA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Evtushenko, Pavel [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Fisher, P. [Massachusetts Institute of Technology, Cambridge, MA (United States); Ihloff, Ernest E. [Hampton University, Hampton, VA (United States); Kalantarians, Narbe [Hampton University, Hampton, VA (United States); Kelleher, Aidan Michael [Massachusetts Institute of Technology, Cambridge, MA (United States); Krossler, W. J. [William and Mary College, Williamsburg, VA (United States); Legg, Robert A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Long, Elena [University of New Hampshire, Durham, NH (United States); Milner, Richard [Massachusetts Institute of Technology, Cambridge, MA (United States); Neil, George R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Ou, Longwu [Massachusetts Institute of Technology, Cambridge, MA (United States); Schmookler, Barack Abraham [Massachusetts Institute of Technology, Cambridge, MA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Tschalar, C. [Massachusetts Institute of Technology, Cambridge, MA (United States); Williams, Gwyn P. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Zhang, Shukui [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2013-11-01

    We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 MeV operation.

  6. Beam lifetime calculation in an electron storage ring for synchrotron radiation

    International Nuclear Information System (INIS)

    In an electron storage ring dedicated for synchrotron radiation, the beam lifetime should be of a few hours, so that the radiation is available to the users for sufficient time. The beam lifetime in an electron storage ring is the average of the finite lifetimes arising due to betatron and energy oscillations, Coulomb scattering and elastic and inelastic scattering of electrons due to residual gases present in the beam tube. A computer program has been written to study the variation of beam lifetime with various machine parameters such as lattice functions, rf voltage, tube aperture etc. The program has been developed to take input data from AGS computer program output. The lifetime of electron beam at lower energies has been studied for a weak focussing electron storage ring and is found to be governed mainly by Coulomb scattering. (author). 3 figs

  7. Optical transition radiation from a thin carbon foil: a beam profile monitor for the SLC

    International Nuclear Information System (INIS)

    This memo considers placement of an ultra thin carbon foil into the SLC beam. Transition radiation light would be emitted from the surface of the foil. The optical spot from the foil could be viewed with a microscope objective lens and registered with an image detector. Multiple scattering for the foil thicknesses necessary will not affect the beam emittance. Calculations show that a thin carbon foil can withstand the electron beam if the electron beam is larger than 10 μm in size. There are many possible radiation mechanisms from a foil - bremsstrahlung, black body temperature radiation, Cerenkov light, scintillation light, and transition radiation. Transition radiation is apparently dominant. It is proposed to use thin carbon foils, 75 to 150 A thick. Calculations indicate that 5 x 1010 beam electrons will radiate a useable number of optical photons. Specifically with 150 A foils the fractional yield of useful optical photons is 10-3 photons per incident electron 5 x 10+7 optical photons imaged upon an image plane. Spread these photons over a 32 x 32 pixel CCD and one has the readout system of a monitor

  8. Calculation of the dose to lymphocytes in external beam radiation therapy

    International Nuclear Information System (INIS)

    Lymphopenia is known to occur in patients undergoing external beam radiation therapy when the radiation fields encompass major blood vessels and lymphatic tissue. The dose received by the lymphocytes has up to now not been determined. We present here a general formalism for the calculation of the lymphocyte dose for a patient undergoing fractionated radiation therapy at any irradiation site. The calculation procedure is demonstrated for a typical case of pelvic irradiation

  9. Calculation of the dose to lymphocytes in external beam radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Ekstrand, K.E.; Dixon, R.L.; Plunkett, S.; Raben, M.

    1981-02-01

    Lymphopenia is known to occur in patients undergoing external beam radiation therapy when the radiation fields encompass major blood vessels and lymphatic tissue. The dose received by the lymphocytes has up to now not been determined. We present here a general formalism for the calculation of the lymphocyte dose for a patient undergoing fractionated radiation therapy at any irradiation site. The calculation procedure is demonstrated for a typical case of pelvic irradiation.

  10. Radiation losses in PLT during neutral beam and ICRF heating experiments

    International Nuclear Information System (INIS)

    Radiation and charge exchange losses in the PLT tokamak are compared for discharges with ohmic heating only (OH), and with additional heating by neutral beams (NB) or RF in the ion cyclotron frequency range (ICRF). Spectroscopic, bolometric and soft x-ray diagnostics were used. The effects of discharge cleaning, vacuum wall gettering, and rate of gas inlet on radiation losses from OH plasmas and the correlation between radiation from plasma core and edge temperatures are discussed

  11. Evaluation of ozone concentration for a white beam line hutch at Indus-2 synchrotron radiation source

    International Nuclear Information System (INIS)

    In the synchrotron radiation source Indus-2, 26 synchrotron radiation beam lines are planned, out of which 7 beam lines are operational and several are in installation stage. For carrying out experiments, SR beam is brought out to air through the beam lines (which are housed in shielded hutches). Due to the interaction of SR with air, ozone is produced, which is a noxious gas and is hazardous, if inhaled in excess. The production of ozone is high in white beam lines in comparison with pink and monochromatic beam lines. In the present paper ozone generation for a white beam line of Indus-2 is estimated. The ozone production rate, saturation concentration, ventilation rate and delay time are also estimated. The saturation concentration of ozone for the white beam line (energy dispersive X-ray diffraction beam line) BL-11 was found to be 0.965 ppm for 100 cm interaction path length and 51.45 m3 hutch volume without any ventilation. The paper presents the details of the calculation and the results. (author)

  12. Effect of electron beam radiations on anxiety in experimental animal models

    International Nuclear Information System (INIS)

    Exposures to ionizing radiation have been an inevitable part of the environment. This type of radiation can disrupt atoms, creating positive and negative charged particles, and cause biological harm. Ionizing radiation includes X-rays, gamma rays, alpha particles, beta particles and neutrons. They have the potential to cause both beneficial and harmful effects. There are concerns about these radiations as they are widely used in hospitals for treatment and diagnosis of various diseases. The present work was designed to test the effect of whole body electron beam radiation on anxiety in mice using the Elevated plus maze and Light dark arena, the commonly used models for assessing anxiety in rodents. Mice were irradiated with three different doses (2 Gy, 4 Gy and 6 Gy) of electron beam radiations. Statistical analysis revealed that whole body irradiation of the moderate dose range (2-6 Gy) of electron beam leads to a significant (p<0.001) anxiogenic activity in irradiated mice. Electron beam induced anxiety can be due to radiation induced reactive oxygen species in brain. (author)

  13. Beam Size Measurement by Optical Diffraction Radiation and Laser System for Compton Polarimeter

    International Nuclear Information System (INIS)

    Beam diagnostics is an essential constituent of any accelerator, so that it is named as 'organs of sense' or 'eyes of the accelerator.' Beam diagnostics is a rich field. A great variety of physical effects or physical principles are made use of in this field. Some devices are based on electro-magnetic influence by moving charges, such as faraday cups, beam transformers, pick-ups; Some are related to Coulomb interaction of charged particles with matter, such as scintillators, viewing screens, ionization chambers; Nuclear or elementary particle physics interactions happen in some other devices, like beam loss monitors, polarimeters, luminosity monitors; Some measure photons emitted by moving charges, such as transition radiation, synchrotron radiation monitors and diffraction radiation-which is the topic of the first part of this thesis; Also, some make use of interaction of particles with photons, such as laser wire and Compton polarimeters-which is the second part of my thesis. Diagnostics let us perceive what properties a beam has and how it behaves in a machine, give us guideline for commissioning, controlling the machine and indispensable parameters vital to physics experiments. In the next two decades, the research highlight will be colliders (TESLA, CLIC, JLC) and fourth-generation light sources (TESLA FEL, LCLS, Spring 8 FEL) based on linear accelerator. These machines require a new generation of accelerator with smaller beam, better stability and greater efficiency. Compared with those existing linear accelerators, the performance of next generation linear accelerator will be doubled in all aspects, such as 10 times smaller horizontal beam size, more than 10 times smaller vertical beam size and a few or more times higher peak power. Furthermore, some special positions in the accelerator have even more stringent requirements, such as the interaction point of colliders and wigglor of free electron lasers. Higher performance of these accelerators increases the

  14. Beam Size Measurement by Optical Diffraction Radiation and Laser System for Compton Polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chuyu [Peking Univ., Beijing (China)

    2012-12-31

    Beam diagnostics is an essential constituent of any accelerator, so that it is named as "organs of sense" or "eyes of the accelerator." Beam diagnostics is a rich field. A great variety of physical effects or physical principles are made use of in this field. Some devices are based on electro-magnetic influence by moving charges, such as faraday cups, beam transformers, pick-ups; Some are related to Coulomb interaction of charged particles with matter, such as scintillators, viewing screens, ionization chambers; Nuclear or elementary particle physics interactions happen in some other devices, like beam loss monitors, polarimeters, luminosity monitors; Some measure photons emitted by moving charges, such as transition radiation, synchrotron radiation monitors and diffraction radiation-which is the topic of the first part of this thesis; Also, some make use of interaction of particles with photons, such as laser wire and Compton polarimeters-which is the second part of my thesis. Diagnostics let us perceive what properties a beam has and how it behaves in a machine, give us guideline for commissioning, controlling the machine and indispensable parameters vital to physics experiments. In the next two decades, the research highlight will be colliders (TESLA, CLIC, JLC) and fourth-generation light sources (TESLA FEL, LCLS, Spring 8 FEL) based on linear accelerator. These machines require a new generation of accelerator with smaller beam, better stability and greater efficiency. Compared with those existing linear accelerators, the performance of next generation linear accelerator will be doubled in all aspects, such as 10 times smaller horizontal beam size, more than 10 times smaller vertical beam size and a few or more times higher peak power. Furthermore, some special positions in the accelerator have even more stringent requirements, such as the interaction point of colliders and wigglor of free electron lasers. Higher performance of these accelerators increases the

  15. Efficacy of electron beams in radiation disinfestation of jute bags

    International Nuclear Information System (INIS)

    An irradiator generating electron radiation may be employed for radiation disinfestation of jute bags infested with larvae and adults of the confused flour beetle, Tribolium confusum DuV., if they are created as separate units or small batches, containing up to 40 bags, and are irradiated with a 2 kGy dose. (author)

  16. Radiation shielding for the ITER neutral beam test facility

    International Nuclear Information System (INIS)

    The NB system for the International Thermonuclear Experimental Reactor (ITER) consists of two heating and current drive (H and CD) NB injectors and a diagnostic neutral beam (DNB) injector. The NB accelerates negative deuterium ions with maximum energy of 1 MeV and maximum beam current of 40 A. The ITER (H and CD) NB will be tested in the Neutral Beam Test Facility (NBTF) that will be located in Italy, near Padua. The performance test will be based on different operation phases starting with low energy hydrogen beam. In the initial testing phase for many months the machine will operate with hydrogen only and with deuteron at a reduced intensity suggesting the possibility of hosting the device in a light shielding room/area. In the paper the study performed to evaluate the minimum shielding needed in connection with the different operation phases is shown. The source terms were calculated starting from neutron source characterisation and then assessing article transport in the ITER NB structure with a mathematical model of the components geometry that was implemented into MCNP computer code. The neutron source definition was outlined considering both D-D and D-T neutron production. Shielding was assessed for hydrogen operation only and for 20, 60, 100 and 1000 kV (full energy) deuteron acceleration, accounting for the associated beam current intensity. Related results are presented and discussed in the paper. (author)

  17. Boosted selective internal radiation therapy with 90Y-loaded glass microspheres (B-SIRT) for hepatocellular carcinoma patients: a new personalized promising concept

    International Nuclear Information System (INIS)

    To evaluate the impact of dosimetry based on MAA SPECT/CT for the prediction of response, toxicity and survival, and for treatment planning in patients with hepatocellular carcinoma (HCC) treated with 90Y-loaded glass microspheres (TheraSphere registered). TheraSphere registered was administered to 71 patients with inoperable HCC. MAA SPECT/CT quantitative analysis was used for the calculation of the tumour dose (TD), healthy injected liver dose (HILD), and total injected liver dose. Response was evaluated at 3 months using EASL criteria. Time to progression (TTP) and overall survival (OS) were evaluated using the Kaplan-Meier method. Factors potentially associated with liver toxicity were combined to construct a liver toxicity score (LTS). The response rate was 78.8 %. Median TD were 342 Gy for responding lesions and 191 Gy for nonresponding lesions (p 205 Gy (p = 0.0015 and not significant). Among patients with portal vein thrombosis (PVT) (n = 33), the median TTP and OS were 4.5 months (2-7 months) and 5 months (2-8 months), respectively, in patients with TD 205 Gy (p = 0.039 and 0.005). The median OS was 24.5 months (18-28.5 months) in PVT patients with TD >205 Gy and good PVT targeting on MAA SPECT/CT. The LTS was able to detect severe liver toxicity (n = 6) with a sensitivity of 83 % and overall accuracy of 97 %. Dosimetry based on MAA SPECT/CT was able to accurately predict response and survival in patients treated with glass microspheres. This method can be used to adapt the injected activity without increasing liver toxicity, thus defining a new concept of boosted selective internal radiation therapy (B-SIRT). This new concept and LTS enable fully personalized treatment planning with glass microspheres to be achieved. (orig.)

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

    Science.gov (United States)

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

    2014-10-01

    The aim of the study was to report the clinical results in patients with high-risk prostate cancer treated with pelvic intensity-modulated radiation therapy (IMRT) and simultaneous integrated boost (SIB) to the prostate area. A total of 110 patients entered our study, 37 patients presented with localized prostate cancer and radiological evidence of node metastases or ≥15% estimated risk of lymph node (LN) involvement, while 73 patients underwent postoperative adjuvant or salvage irradiation for biochemical or residual/recurrent disease, LN metastases, or high risk of harboring nodal metastases. All patients received androgen deprivation therapy (ADT) for 2 years. The median follow-up was 56.5 months. For the whole patient group, the 3- and 5-year freedom from biochemical failure were 82.6% and 74.6%, respectively, with a better outcome in patients treated with radical approach. The 3- and 5-year freedom from local failure were 94.4% and 90.2%, respectively, while the 3- and 5-year distant metastasis-free survival were 87.8% and 81.7%, respectively. For all study patients, the rate of freedom from G2 acute rectal, intestinal, and urinary toxicities was 60%, 77%, and 61%, respectively. There was no G3 acute toxicity, ≥G2 late intestinal toxicity, or G3 late urinary or rectal toxicity. The 3- and 5-year ≥G2 freedom from late rectal toxicity rate were 98% and 95%, respectively, while the 3- and 5-year ≥G2 freedom from late urinary toxicity rate were 95% and 88%, respectively. The study concludes that pelvic IMRT and SIB to the prostatic area in association with 2-year ADT was a well-tolerated technique, providing high disease control in patients with prostate cancer requiring LN treatment. PMID:24976538

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-12-01

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

  1. INFLUENCE OF INCUBATION TIME, GAMMA RAYS AND ELECTRON BEAM ON RADIATION RESISTANCE OF SOME SELECTED PATHOGENS

    International Nuclear Information System (INIS)

    The effect of different growth phases on the radiation resistance, antibiotic susceptibility and pathogenicity of certain selected pathogens (Escherichia coli, Candida albicans and Staphylococcus aureus) was studied in mice. The obtained results showed that Escherichia coli was slightly more resistant to gamma radiation in 18 h than 24 h or 48 h but it was relatively more resistant to electron beam in 24 h and 48 h than 18 h. Candida albicans showed radiation resistance nearly the same in all incubation times in the case of gamma radiation while for electron beam, its radiation resistance was slightly more in 24 h and 48 h than in 18 h. On the other hand, Staphylococcus aureus recorded much more resistance to gamma radiation in the 48 h than in 24 h or 18 h whereas in the case of electron beam, it was slightly more resistant in 18 h than in 24 h and 48 h.The antibiotic susceptibility of Escherichia coli reported that the exposure to gamma radiation at 3 kGy and electron beam at 6 kGy increase the susceptibility to the nalidixic acid and nitrofurantoin. When Candida albicans was exposed to 3 kGy gamma radiation and 6 kGy electron beam, the same sensitivity to nystatin was observed in comparison with the unexposed one while the sensitivity of Staphylococcus aureus to some antibiotics (amoxicillin, nitrofurantoin and tetracycline) was decreased after exposure to gamma radiation at 0.75 and 2 kGy and electron beam at 6 kGy, but for other antibiotics (trimethoprim/ sulfamethoxazole), the sensitivity was increased at 6 kGy electron beam.The lethality percent recorded after the oral ingestion of the mice with the unexposed Escherichia coli and Candida albicans were 25% and 100%, respectively, and for 6 kGy exposure to electron beam was 0% . The cotaneous disease and abscesses caused by the intradermal injection of the mice with unexposed Staphylococcus aureus was 75% and for 6 kGy exposure to electron beam was 25%.

  2. A surrogate-based metaheuristic global search method for beam angle selection in radiation treatment planning

    International Nuclear Information System (INIS)

    An important element of radiation treatment planning for cancer therapy is the selection of beam angles (out of all possible coplanar and non-coplanar angles in relation to the patient) in order to maximize the delivery of radiation to the tumor site and minimize radiation damage to nearby organs-at-risk. This category of combinatorial optimization problem is particularly difficult because direct evaluation of the quality of treatment corresponding to any proposed selection of beams requires the solution of a large-scale dose optimization problem involving many thousands of variables that represent doses delivered to volume elements (voxels) in the patient. However, if the quality of angle sets can be accurately estimated without expensive computation, a large number of angle sets can be considered, increasing the likelihood of identifying a very high quality set. Using a computationally efficient surrogate beam set evaluation procedure based on single-beam data extracted from plans employing equally-spaced beams (eplans), we have developed a global search metaheuristic process based on the nested partitions framework for this combinatorial optimization problem. The surrogate scoring mechanism allows us to assess thousands of beam set samples within a clinically acceptable time frame. Tests on difficult clinical cases demonstrate that the beam sets obtained via our method are of superior quality. (paper)

  3. Fracture analysis of HFIR beam tube caused by radiation embrittlement

    Energy Technology Data Exchange (ETDEWEB)

    Chang, S.J. [Oak Ridge National Lab., TN (United States). Research Reactors Div.

    1994-12-31

    With an attempt to estimate the neutron beam tube embrittlement condition for the Oak Ridge High Flux Isotope Reactor (HFIR), fracture mechanics calculations are carried out in this paper. The analysis provides some numerical result on how the tube has been structurally weakened. In this calculation, a lateral impact force is assumed. Numerical result is obtained on how much the critical crack size should be reduced if the beam tube has been subjected to an extended period of irradiation. It is also calculated that buckling strength of the tube is increased, not decreased, with irradiation.

  4. TH-C-17A-09: Direct Visualization and Monitoring of Medical Radiation Beams in Air

    Energy Technology Data Exchange (ETDEWEB)

    Fahimian, B; Ceballos, A; Turkcan, S; Kapp, D; Pratx, G [Stanford University, Stanford, CA (United States)

    2014-06-15

    Purpose: Radiation therapy errors are rare but potentially catastrophic. Recent fatal incidents could have been avoided by utilizing real-time methods of monitoring delivery of radiation during treatment. However, few existing methods are practical enough to be used routinely. The study presents the first experimental demonstration of a novel non-perturbing method of monitoring radiation therapy through the phenomena of air scintillation. Methods: Monitoring of radiation delivery was devised by leveraging the phenomena of nitrogen excitation in air by ionizing radiation. The excitation induced weak luminescence in the 300–400 nm range, a process called air scintillation. An electron-multiplication charge-coupled device camera (f/0.95 lens; 440 nm shortpass) was set-up in a clinical treatment vault and was used to capture air scintillation images of kilovoltage and megavoltage beams. Monte Carlo simulations were performed to determine the correlation of radiation dose to air scintillation. Results: Megavoltage beams from a Varian Clinac 21EX and kilovoltage beams from an orthovoltage unit (50 kVp, 30 mA) were visualized with a relatively short exposure time (10 s). Cherenkov luminescence produced in a plastic transparent phantom did not interfere with detection of air scintillation. The image intensity displayed an inverse intensity falloff (r{sup 2} = 0.89) along the central axis and was proportional to dose rate (r{sup 2} = 0.9998). As beam energy increased, the divergence of the imaged beam decreased. Last, air scintillation was visualized during a simulated total skin irradiation electron treatment. Conclusion: Air scintillation can be clinically detected to monitor a radiation beam in an inexpensive and non-perturbing manner. This new method is advantageous in monitoring for gross delivery and uniquely capable of wide area in a single acquisition, such as the case for online verification of total body / skin / lymphoid irradiation treatments.

  5. Feasibility and efficacy of simultaneous integrated boost intensity-modulated radiation therapy in patients with limited-disease small cell lung cancer

    International Nuclear Information System (INIS)

    To evaluate the feasibility and efficacy of simultaneous integrated boost intensity-modulated radiation therapy (SIB-IMRT) in patients with limited-disease small-cell lung cancer (LD-SCLC). Patients with LD-SCLC were treated with SIB-IMRT within 1 week after completion of 2 cycles of induction chemotherapy. Then 2-4 cycles of adjuvant chemotherapy were administered within 1 week after SIB-IMRT. Irradiation was given accelerated hyper-fractionated with the prescribed dose 57Gy at 1.9Gy twice daily to the gross tumor volume (GTV) , 51Gy at 1.7Gy twice daily to the clinical tumor volume (CTV) and 45Gy at 1.5Gy twice daily to the planning target volume (PTV). The chemotherapy regimen consisted of platinum plus etoposide. Prophylactic cranial radiation (25Gy in 10 fractions) was administered to patients who got complete response (CR) or near complete response (nCR). The primary endpoint of this study was the frequency of grade 3 or higher acute non-hematologic treatment-related toxicities. Secondary end points included objective response, overall survival (OS), progression-free survival (PFS), locoregional recurrence-free survival (LRFS). A cohort of 35 patients were enrolled in the study, the biological equivalent dose (BED) of the GTV in the SIB-IMRT was 59.16Gy. Grade 1, 2, and 3 esophagitis were observed in 11 (31%), 12 (34%), and 6 (17%) patients, respectively; Grade 1 and 2 pneumonitis were observed in 8 (23%) and 4 (11%) patients, respectively. The median OS and PFS of the whole group were 37.7 months and 29.3 months, respectively. The 1- and 2-year OS was 94.1% and 68.5%, respectively. The 1- and 2-year PFS was 76.8% and 40.7%, respectively. The 1- and 2-year LRFS was 87.7% and 73.8%, respectively. SIB-IMRT was feasible and well-tolerated in patients with LD-SCLC, and worth further evaluating in a large prospective clinical trial

  6. Acoustical radiation torque and force for spheres and Bessel beam extinction efficiency

    Science.gov (United States)

    Marston, Philip L.; Zhang, Likun

    2014-11-01

    The scattering of optical and acoustical beams is relevant to the levitation and manipulation of drops. Here we examine theoretical developments in the acoustical case. We previously showed how the optical theorem for extinction can be extended to invariant beams. The example of a sphere in a Bessel beam facilitates the direct comparison with a circular disc computed using Babinet's principle and the Kirchhoff approximation. In related work, by considering traveling or standing wave first-order vortex beams we previously showed that the radiation torque is the ratio of the absorbed power and the radian acoustic frequency. By modifying the scattering to account for the viscosity of the surrounding fluid in the analysis of the absorbed power, approximations for radiation torque and force are obtained at long wavelengths in special cases and these can be compared with results published elsewhere.

  7. Resonant terahertz radiation from warm collisional inhomogeneous plasma irradiated by two Gaussian laser beams

    Science.gov (United States)

    Niknam, A. R.; Banjafar, M. R.; Jahangiri, F.; Barzegar, S.; Massudi, R.

    2016-05-01

    Terahertz (THz) radiation generation by the interaction of two co-propagating high intensity laser beams with a warm collisional inhomogeneous plasma is analytically investigated. By presenting the dielectric permittivity of plasma and taking into account the ponderomotive force, the nonlinear current at THz frequency is obtained. A secondary resonant enhancement of THz radiation is observed, in addition to that occurs at the plasma frequency, which can be tuned by plasma density and temperature. Moreover, we show that for each beat frequency, there exists an optimum temperature at which THz radiation is maximized. It is also shown that the power and efficiency of THz radiation decrease by increasing the collision frequency.

  8. Radiation tolerant programmable power supply for the LHC beam screen heaters

    International Nuclear Information System (INIS)

    For the next LHC run, it is required to install 200 W of heating capacity per LHC beam screen heater to regenerate the beam screen by desorption of gas trapped on its walls. In the LHC, there are 272 beam screen heaters and the associated electronics limit presently the heating capacity to 25 W. Those electronics are, for the most part, installed inside the LHC tunnel and exposed to its radiation environment. This paper describes the development of a new programmable power supply card that will be integrated into the existing LHC radiation tolerant electronic infrastructure used by the cryogenic system. Radiation tests were undertaken to qualify a power switch capable of coping with the 230 Vrms grid voltage and an analog signal multiplexer; these components are required respectively for satisfying the higher power requirements and for reducing the overall cost by using a single analog to digital converter to sample all the signals

  9. Radiation tolerant programmable power supply for the LHC beam screen heaters

    Science.gov (United States)

    Casas, J.; Trikoupis, N.

    2014-03-01

    For the next LHC run, it is required to install 200 W of heating capacity per LHC beam screen heater to regenerate the beam screen by desorption of gas trapped on its walls. In the LHC, there are 272 beam screen heaters and the associated electronics limit presently the heating capacity to 25 W. Those electronics are, for the most part, installed inside the LHC tunnel and exposed to its radiation environment. This paper describes the development of a new programmable power supply card that will be integrated into the existing LHC radiation tolerant electronic infrastructure used by the cryogenic system. Radiation tests were undertaken to qualify a power switch capable of coping with the 230 Vrms grid voltage and an analog signal multiplexer; these components are required respectively for satisfying the higher power requirements and for reducing the overall cost by using a single analog to digital converter to sample all the signals.

  10. Betatron radiation based diagnostics for plasma wakefield accelerated electron beams at the SPARC_LAB test facility

    Science.gov (United States)

    Shpakov, V.; Anania, M. P.; Biagioni, A.; Chiadroni, E.; Cianchi, A.; Curcio, A.; Dabagov, S.; Ferrario, M.; Filippi, F.; Marocchino, A.; Paroli, B.; Pompili, R.; Rossi, A. R.; Zigler, A.

    2016-09-01

    Recent progress with wake-field acceleration has shown a great potential in providing high gradient acceleration fields, while the quality of the beams remains relatively poor. Precise knowledge of the beam size at the exit from the plasma and matching conditions for the externally injected beams are the key for improvement of beam quality. Betatron radiation emitted by the beam during acceleration in the plasma is a powerful tool for the transverse beam size measurement, being also non-intercepting. In this work we report on the technical solutions chosen at SPARC_LAB for such diagnostics tool, along with expected parameters of betatron radiation.

  11. Seeing the invisible: Direct visualization of therapeutic radiation beams using air scintillation

    Energy Technology Data Exchange (ETDEWEB)

    Fahimian, Benjamin; Türkcan, Silvan; Kapp, Daniel S.; Pratx, Guillem, E-mail: pratx@stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California 94305 (United States); Ceballos, Andrew [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2014-01-15

    Purpose: To assess whether air scintillation produced during standard radiation treatments can be visualized and used to monitor a beam in a nonperturbing manner. Methods: Air scintillation is caused by the excitation of nitrogen gas by ionizing radiation. This weak emission occurs predominantly in the 300–430 nm range. An electron-multiplication charge-coupled device camera, outfitted with an f/0.95 lens, was used to capture air scintillation produced by kilovoltage photon beams and megavoltage electron beams used in radiation therapy. The treatment rooms were prepared to block background light and a short-pass filter was utilized to block light above 440 nm. Results: Air scintillation from an orthovoltage unit (50 kVp, 30 mA) was visualized with a relatively short exposure time (10 s) and showed an inverse falloff (r{sup 2} = 0.89). Electron beams were also imaged. For a fixed exposure time (100 s), air scintillation was proportional to dose rate (r{sup 2} = 0.9998). As energy increased, the divergence of the electron beam decreased and the penumbra improved. By irradiating a transparent phantom, the authors also showed that Cherenkov luminescence did not interfere with the detection of air scintillation. In a final illustration of the capabilities of this new technique, the authors visualized air scintillation produced during a total skin irradiation treatment. Conclusions: Air scintillation can be measured to monitor a radiation beam in an inexpensive and nonperturbing manner. This physical phenomenon could be useful for dosimetry of therapeutic radiation beams or for online detection of gross errors during fractionated treatments.

  12. Beam-centric algorithm for pretreatment patient position correction in external beam radiation therapy

    International Nuclear Information System (INIS)

    Purpose: In current image guided pretreatment patient position adjustment methods, image registration is used to determine alignment parameters. Since most positioning hardware lacks the full six degrees of freedom (DOF), accuracy is compromised. The authors show that such compromises are often unnecessary when one models the planned treatment beams as part of the adjustment calculation process. The authors present a flexible algorithm for determining optimal realizable adjustments for both step-and-shoot and arc delivery methods. Methods: The beam shape model is based on the polygonal intersection of each beam segment with the plane in pretreatment image volume that passes through machine isocenter perpendicular to the central axis of the beam. Under a virtual six-DOF correction, ideal positions of these polygon vertices are computed. The proposed method determines the couch, gantry, and collimator adjustments that minimize the total mismatch of all vertices over all segments with respect to their ideal positions. Using this geometric error metric as a function of the number of available DOF, the user may select the most desirable correction regime. Results: For a simulated treatment plan consisting of three equally weighted coplanar fixed beams, the authors achieve a 7% residual geometric error (with respect to the ideal correction, considered 0% error) by applying gantry rotation as well as translation and isocentric rotation of the couch. For a clinical head-and-neck intensity modulated radiotherapy plan with seven beams and five segments per beam, the corresponding error is 6%. Correction involving only couch translation (typical clinical practice) leads to a much larger 18% mismatch. Clinically significant consequences of more accurate adjustment are apparent in the dose volume histograms of target and critical structures. Conclusions: The algorithm achieves improvements in delivery accuracy using standard delivery hardware without significantly increasing

  13. Automatic beam position control at Los Alamos Spallation Radiation Effects Facility (LASREF)

    International Nuclear Information System (INIS)

    Historically the Los Alamos Spallation Radiation Effects Facility (LASREF) has used manual methods to control the position of the 800 kW, 800 MeV proton beam on targets. New experiments, however, require more stringent position control more frequently than can be done manually for long periods of time. Data from an existing harp is used to automatically adjust steering magnets to maintain beam position to required tolerances

  14. Radiation Exposure of Patients by Cone Beam CT during Endobronchial Navigation - A Phantom Study

    OpenAIRE

    Hohenforst-Schmidt, Wolfgang; Banckwitz, Rosemarie; Zarogoulidis, Paul; Vogl, Thomas; Darwiche, Kaid; Goldberg, Eugene; Huang, Haidong; Simoff, Michael; Li, Qiang; Browning, Robert; Freitag, Lutz; Turner, J. Francis; Pivert, Patrick Le; Yarmus, Lonny; Zarogoulidis, Konstantinos

    2014-01-01

    Rationale: Cone Beam Computed Tomography imaging has become increasingly important in many fields of interventional therapies. Objective: Lung navigation study which is an uncommon soft tissue approach. Methods: As no effective organ radiation dose levels were available for this kind of Cone Beam Computed Tomography application we simulated in our DynaCT (Siemens AG, Forchheim, Germany) suite 2 measurements including 3D acquisition and again for 3D acquisition and 4 endobronchial navigation m...

  15. Image-guided small animal radiation research platform: calibration of treatment beam alignment

    International Nuclear Information System (INIS)

    Small animal research allows detailed study of biological processes, disease progression and response to therapy with the potential to provide a natural bridge to the clinical environment. The small animal radiation research platform (SARRP) is a portable system for precision irradiation with beam sizes down to approximately 0.5 mm and optimally planned radiation with on-board cone-beam CT (CBCT) guidance. This paper focuses on the geometric calibration of the system for high-precision irradiation. A novel technique for the calibration of the treatment beam is presented, which employs an x-ray camera whose precise positioning need not be known. Using the camera system we acquired a digitally reconstructed 3D 'star shot' for gantry calibration and then developed a technique to align each beam to a common isocenter with the robotic animal positioning stages. The calibration incorporates localization by cone-beam CT guidance. Uncorrected offsets of the beams with respect to the calibration origin ranged from 0.4 mm to 5.2 mm. With corrections, these alignment errors can be reduced to the sub-millimeter range. The calibration technique was used to deliver a stereotactic-like arc treatment to a phantom constructed with EBT Gafchromic films. All beams were shown to intersect at a common isocenter with a measured beam (FWHM) of approximately 1.07 mm using the 0.5 mm collimated beam. The desired positioning accuracy of the SARRP is 0.25 mm and the results indicate an accuracy of 0.2 mm. To fully realize the radiation localization capabilities of the SARRP, precise geometric calibration is required, as with any such system. The x-ray camera-based technique presented here provides a straightforward and semi-automatic method for system calibration.

  16. Radiation protection commissioning of neutron beam instruments at the OPAL research reactor

    International Nuclear Information System (INIS)

    The neutron beam facilities at the 20 MW OPAL Research Reactor were commissioned in 2007 and 2008. The initial suite of eight neutron beam instruments on two thermal neutron guides, two cold neutron guides and one thermal beam port located at the reactor face, together with their associated shielding were progressively installed and commissioned according to their individual project plans. Radiation surveys were systematically conducted as reactor power was raised in a step-wise manner to 20 MW in order to validate instrument shielding design and performance. The performance of each neutron guide was assessed by neutron energy spectrum and flux measurements. The activation of beam line components, decay times assessments and access procedures for Bragg Institute beam instrument scientists were established. The multiple configurations for each instrument and the influence of operating more than one instrument or beamline simultaneously were also tested. Areas of interest were the shielding around the secondary shutters, guide shield and bunker shield interfaces and monochromator doors. The shielding performance, safety interlock checks, improvements, radiation exposures and related radiation protection challenges are discussed. This paper discusses the health physics experience of commissioning the OPAL Research Reactor neutron beam facilities and describes health physics results, actions taken and lessons learned during commissioning. (author)

  17. Radiation protection commissioning of neutron beam instruments at the OPAL Research Reactor

    International Nuclear Information System (INIS)

    The neutron beam facilities at the 20 MW OPAL Research Reactor were commissioned in 2007 and 2008. The initial suite of eight neutron beam instruments on two thermal neutron guides, two cold neutron guides and one thermal beam port located at the reactor face, together with their associated shielding were progressively installed and commissioned according to their individual project plans. Radiation surveys were systematically conducted as reactor power was raised in a step-wise manner to 20MW in order to validate instrument shielding design and performance. The performance of each neutron guide was assessed by neutron energy spectrum and flux measurements. The activation of beam line components, decay times assessments and access procedures for Bragg Institute beam instrument scientists were established. The multiple configurations for each instrument and the influence of operating more than one instrument or beamline simultaneously were also tested. Areas of interest were the shielding around the secondary shutters, guide shield and bunker shield interfaces and monochromator doors. The shielding performance, safety interlock checks, improvements, radiation exposures and related radiation protection challenges are discussed. This paper discusses the health physics experience of commissioning the OPAL Research Reactor neutron beam facilities and describes health physics results, actions taken and lessons learned during commissioning. (author)

  18. Beam standardization of X radiation in computed tomography

    International Nuclear Information System (INIS)

    The ionization chamber used in dosimetric procedures in computed tomography beams (CT), is a cylindrical chamber, unsealed, with the sensitive length between 10 and 15 cm, named pencil ionization chamber. Because the doses involved in CT procedures are higher s than those in the procedures in radiology, it is very important to ensure the appropriate calibration of pencil ionization chambers and thus the accuracy of Dosimetric procedures. Recently, only the Calibration Laboratory, from Institute de Pesquisas Energeticas e Nucleares, had standards fields of conventional radiodiagnostic, but not arrived to include the energy range used in CT. In this work, will be shown the results obtained in standard field of radiodiagnostic - all qualities of radiodiagnostic of series RQR (direct beam) and RQA (attenuated beam) described in IEC 61267 norm - in an industrial X-ray equipment of the Calibration Laboratory. The recommended qualities for the calibration of TC chambers are the qualities RQA9 and RQR9. The other qualities will be used for calibration of other radiodiagnostic dosimeters and also for a larger study of the energy dependence of the pencil ionization chambers

  19. Economical aspects of radiation sterilization with electron beam

    International Nuclear Information System (INIS)

    Radiation sterilization has been introduced in Poland in the early seventies. Since then continuous progress is observed in quantity of sterilized products. The commercial irradiation facility was built in 1993 to fulfill growing demands for radiation service. The real costs of running this plant were shown. The share of the cost of investment and the cost of maintenance and spare parts in accelerator exploitation, as well as the cost of one hour accelerator exploitation against time of one year accelerator exploitation were taken into account

  20. Radiative and collisional processes of highly charged heavy ions studied with electron beam ion traps

    International Nuclear Information System (INIS)

    We have been studying radiative and collisional processes of highly charged heavy ions using two electron beam ion traps (EBITs) at the University of Electro-Communications (UEC/Tokyo); one is the Tokyo-EBIT constructed in 1995 for the operation with a high energy (up to 200 keV) electron beam, and another is “CoBIT” constructed recently for the operation with a low energy (< 1 keV) electron beam. Recent activities using the two EBITs are presented. (author)

  1. Electron Beam Spectrum Diagnostics with Optical Transition Radiation on the Beijing Free-Electron Laser

    Institute of Scientific and Technical Information of China (English)

    李泉凤; 吴频; 高建江; 吴刚

    2004-01-01

    A measurement system was developed to measure the electron beam spectrum of the Beijing free-electron laser based on the optical transition radiation (OTR). This paper describes the system, which consists of a 32-channel high resolution of 0.02% OTR detector, especially the spectrometer. The OTR angular-distribution pattern at the focal plane has two apexes, but the two apexes are smoothed out due to the electron beam energy distribution. The energy spectrum can be measured if the magnet energy resolution is higher than 0.7% to distinguish the electron beam energy distribution.

  2. Audit of high energy therapy beams in hospital oncology departments by the National Radiation Laboratory

    International Nuclear Information System (INIS)

    In 1993 the output of every high energy radiotherapy beam used clinically in New Zealand was measured by National Radiation Laboratory (NRL) staff using independent dosimetry equipment. The purpose of this was to audit the dosimetry that is used by hospital physicists for the basis of patient treatments, and to uncover any errors that may be clinically significant. This report analyses the uncertainties involved in comparing the NRL and hospital measurements, and presents the results of the 1993 audit. The overall uncertainty turns out to be about 1.5%. The results for linear accelerator photon beams are consistent with a purely random variation within this uncertainty. Electron beams show some small errors beyond the expected uncertainty. Gamma beams have the potential to be the most accurately measured, but in practice are less accurately measured than linear accelerator beams. None of the disagreements indicated an error of clinical significance. 8 refs., 3 figs., 2 tabs

  3. Time-Resolved Emittance Characterization of an Induction Linac Beam using Optical Transition Radiation

    International Nuclear Information System (INIS)

    An induction linac is used by Lawrence Livermore National Laboratory to perform radiographic testing at the Flash X-ray Radiography facility. Emittance characterization is important since x-ray spot size impacts the resolution of shadow-graphs. Due to the long pulse length, high current, and beam energy, emittance measurement using Optical Transition Radiation is an attractive alternative for reasons that will be described in the text. The utility of OTR-based emittance measurement has been well demonstrated for both RF and induction linacs. We describe the time-resolved emittance characterization of an induction linac electron beam. We have refined the optical collection system for the induction linac application, and have demonstrated a new technique for probing the divergence of a subset of the beam profile. The experimental apparatus, data reduction, and conclusions will be presented. Additionally, a new scheme for characterizing the correlation between beam divergence and spatial coordinates within the beam profile will be described

  4. Synchrotron Radiation and beam tube vacuum in a Very Large Hadron Collider; Stage 1 VLHC

    International Nuclear Information System (INIS)

    Synchrotron radiation induced photodesorption in particle accelerators may lead to pressure rise and to beam-gas scattering losses, finally affecting the beam lifetime. We discuss the beam tube vacuum in the low field Stage 1 Very Large Hadron Collider VLHC. Since VLHC Stage 1 has a room temperature beam tube, a non-evaporable getter (NEG St101 strip) pumping system located inside a pumping antechamber, supplemented by lumped ion pumps for pumping methane is considered. A possible beam conditioning scenario is presented for reaching design intensity. The most important results are summarized in this paper. More detailed reports of the calculations will be presented at the PAC2001 Conference, Chicago, IL to be held in June 2001, and at the Snowmass Conference, CO, to be held on July 2001

  5. Use of high-power electron beam radiation for the treatment of municipal and industrial wastes

    International Nuclear Information System (INIS)

    One of the factors impeding the use of ionizing radiation for waste treatment has been the relatively high cost of large radiation sources. This obstacle has been reduced by the recent development of powerful electron beam accelerators that are now being used by many manufacturers to crosslink plastic and rubber compounds, and to sterilize ethical products. The industrial demand for radiation processing equipment has produced a new technology which can be applied to the irradiation of waste materials. Electron accelerators can now provide 150 kW of useful beam power for continuous service. Such machines could process 3.1 MGD(million US gallons daily) of water to an average dose of 0.1 Mrad. The unit cost for the radiation process would be about $0.22 per 1000 gallons. Larger systems delivering up to a megawatt of power could be developed within a few years if needed for large-scale applications. Such equipment would bring the radiation processing cost down still further and would increase the capacity to about 22 MGD. This throughput would be comparable with the waste water effluent of large sewage treatment plants in the New York City area. High-power electron beams may be particularly useful in the treatment of gaseous wastes. The irradiation of stack gases from large electric power stations, a process that is now being investigated in Japan, is a possible application that could justify the development of multi-megawatt electron beam systems. (Author)

  6. Mo/Si multilayer-coated amplitude-division beam splitters for XUV radiation sources

    International Nuclear Information System (INIS)

    Short-wavelength XUV beam splitters consisting of multilayer reflective and transmissive coatings on 3 × 3 mm and 10 × 10 mm SiN membranes have been developed and fully characterized. Amplitude-division beam splitters for XUV radiation sources have been developed and extensively characterized. Mo/Si multilayer coatings were deposited on 50 nm-thick SiN membranes. By changing the multilayer structure (periodicity, number of bilayers, etc.) the intensity of the reflected and transmitted beams were optimized for selected incident radiation parameters (wavelength, incident angle). The developed optical elements were characterized by means of XUV reflectometry and transmission measurements, atomic force microscopy and optical interferometry. Special attention was paid to the spatial homogeneity of the optical response and reflected beam wavefront distortions. Here the results of the characterization are presented and improvements required for advanced applications at XUV free-electron lasers are identified. A flatness as low as 4 nm r.m.s. on 3 × 3 mm beam splitters and 22 nm r.m.s. on 10 × 10 mm beam splitters has been obtained. The high-spatial-frequency surface roughness was about 0.7–1 nm r.m.s. The middle-spatial-frequency roughness was in the range 0.2–0.8 nm r.m.s. The reflection and transmission of the beam splitters were found to be very homogeneous, with a deviation of less than 2% across the full optical element

  7. Optimal beam arrangement for stereotactic body radiation therapy delivery in lung tumors

    International Nuclear Information System (INIS)

    Purpose. To compare the different beam arrangement and delivery techniques for stereotactic body radiation therapy (SBRT) of lung lesions using the criteria of Radiation Therapy Oncology Group (RTOG) 0236 protocol. Material and methods. Thirty-seven medically inoperable lung cancers were evaluated with various planning techniques including multiple coplanar multiple static beams, multiple non-coplanar static beams and arc delivery. Twelve plans were evaluated for each case, including five plans using coplanar fixed beams, six plans using non-coplanar fixed beams and one plan using arc therapy. These plans were compared using the target prescription isodose coverage, high and low dose volumes, and critical organ dose-volume limits. Results. The prescription isodose coverage, high dose evaluation criteria and dose to critical organs were similar among treatment delivery techniques. However, there were differences in low dose criteria, especially in the ratio of the volume of 50% isodose of the prescription dose to the volume of planning treatment volume (R50%). The R50% in plans using non-coplanar static beams was lower than other plans in 30 of 37 cases (81%). Conclusion. Based on the dosimetric criteria outlined in RTOG 0236, the treatment technique using non-coplanar static beams showed the most preferable results for SBRT of lung lesions

  8. Enhancement of FEM radiation by prebunching of the e-beam (stimulated super-radiance)

    CERN Document Server

    Arbel, M; Kleinman, H; Yakover, I M; Abramovich, A; Pinhasi, Y; Luria, Y; Tecimer, M; Gover, A

    2001-01-01

    An electron beam (e-beam) prebunched at the synchronous FEM frequency and traversing through a waveguide, located coaxially with a magnetic undulator, emits coherent radiation at the bunching frequency. Introduction of both a premodulated e-beam and a radio-frequency (r.f.) signal at the same frequency at the input of the waveguide can lead to more efficient interaction, and thus more power can be extracted from the electron beam. In order to achieve this, the density modulation of the electron beam should be at an appropriate phase with respect to the r.f. signal. We report a first experimental demonstration of the influence of the phase difference between the r.f. input signal and the fundamental component of the density modulation of the e-beam on the radiated power in a Free-Electron Maser (FEM). Our experimental system allows control of the current density modulation, of the r.f. input power level, in the undulator region and of the phase between that r.f. input and the modulation of the e-beam. A compar...

  9. Generation of Shaped beam Radiation patterns from a Line source using Iterative sampling method

    Directory of Open Access Journals (Sweden)

    G.R.L.V.N.Srinivasa Raju

    2013-08-01

    Full Text Available For the generation of cosecant and trapezoidal radiation patterns an iterative sampling method is introduced by Stutzman. In this paper, an original radiation pattern which is some approximation to the desired radiation pattern is generated by a standard synthesis method and a series of correction patterns are applied to it by addinga correction pattern. This process is continued until the desired performance is achieved. In the present work, ramp, sector, cosecant, trapezoidal and stair stepped radiation patterns are generated using iterative procedure. The current distribution is found after corrections are applied. Studies are made with good number of examples, which showed that patterns with low side lobe level or low main beam ripple or sharp cut off from the main beam can be obtained. An iterative procedure is simple and converges rapidly.

  10. Prescription dose analysis and evaluation of carcinoma of breast on 60Co radiation beam

    International Nuclear Information System (INIS)

    To report the outcome of breast cancer patients treated radically by External Beam Radiotherapy (EBRT) and Chemotherapy. Radiation therapy along with chemotherapy plays an important role in the treatment of breast cancer. In breast tumour management the role of post mastectomy chest wall irradiation in improving the local control is well known. It is important to practice optimal radiation therapy in order to achieve high loco-regional control with minimal morbidity

  11. Generation of Longitudinally Polarised Terahertz Radiation for the Energy Manipulation of Relativistic Electron Beams

    OpenAIRE

    Cliffe, Matthew

    2016-01-01

    The University of Manchester Matthew J. Cliffe Doctor of Philosophy Generation of Longitudinally Polarised Terahertz Radiation for the Energy Manipulation of Relativistic Electron BeamsSeptember 2015The acceleration of charged particles with ultrafast terahertz electromagnetic radiation could enable new, and improve many of aspects of, accelerator applications. These include providing shorter electron bunches for ultrafast time-resolved pump-probe spectroscopy, enabling complex longitudinal p...

  12. Boosted selective internal radiation therapy with {sup 90}Y-loaded glass microspheres (B-SIRT) for hepatocellular carcinoma patients: a new personalized promising concept

    Energy Technology Data Exchange (ETDEWEB)

    Garin, E.; Lenoir, L. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Nuclear Medicine, CS 44229, Rennes (France); University of Rennes 1, Rennes (France); INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Edeline, J. [University of Rennes 1, Rennes (France); Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Oncology, CS 44229, Rennes (France); Laffont, S. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Nuclear Medicine, CS 44229, Rennes (France); Mesbah, H.; Poree, P. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Informatics, CS 44229, Rennes (France); Sulpice, L. [INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Centre Hospitalier Universitaire Pontchaillou, Department of Digestive Surgery, Rennes (France); Boudjema, K. [University of Rennes 1, Rennes (France); INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Centre Hospitalier Universitaire Pontchaillou, Department of Digestive Surgery, Rennes (France); Mesbah, M. [University of Pierre et Marie Curie, Paris (France); Guillygomarc' h, A. [Centre Hospitalier Universitaire Pontchaillou, Department of Hepatology, Rennes (France); Quehen, E. [Centre Hospitalier Universitaire Pontchaillou, Department of Radiology, Rennes (France); Pracht, M. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Oncology, CS 44229, Rennes (France); Raoul, J.L. [Comprehensive Cancer Center, Institute Paoli Calmette, Department of Medical Oncology, Marseille (France); Clement, B. [INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Rolland, Y. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Imaging, CS 44229, Rennes (France); Boucher, E. [INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Oncology, CS 44229, Rennes (France)

    2013-07-15

    able to accurately predict response and survival in patients treated with glass microspheres. This method can be used to adapt the injected activity without increasing liver toxicity, thus defining a new concept of boosted selective internal radiation therapy (B-SIRT). This new concept and LTS enable fully personalized treatment planning with glass microspheres to be achieved. (orig.)

  13. Dosimetric Audits of Photon Beams in Radiation Therapy Centres

    International Nuclear Information System (INIS)

    Data related to eleven years of high-energy photon radiotherapy beams dosimetry are presented and analyzed. Dosimetric evaluations were carried out using water phantoms and thimble ionization chambers. Measurements were done at reference conditions for a standard absorbed dose of 100 cGy. The first dosimetry surveys from 1996 to 1998 showed deviations of 22% and 18.7%, although small deviations were also obtained. After 1998 the improvement of dosimetry quality control by the radiotherapy centers became clear, with most of the deviations situated within the ±3% range. (author)

  14. Particle beams in ultrastrong laser fields: direct laser acceleration and radiation reaction effects

    Science.gov (United States)

    Salamin, Yousef I.; Li, Jian-Xing; Hatsagortsyan, Karen Z.; Tamburini, Matteo; Di Piazza, Antonino; Keitel, Christoph H.

    2015-03-01

    Several aspects of the interaction of particle beams with ultrastrong laser fields are discussed. Firstly, we consider regimes when radiation reaction is not essential and it is demonstrated that employing chirped laser pulses, significant improvement of the direct acceleration of particles can be achieved. Results from single- and many-particle calculations of the particle acceleration, in vacuum, by plane-wave fields, as well as in tightly-focused laser beams, show that the mean energies and their spreads qualify them for important applications. Secondly, we investigate the effect of radiation reaction in electron-laser-beam interactions. Signatures of the quantum radiation reaction during the interaction of an electron bunch with a focused superstrong ultrashort laser pulse can be observed in a characteristic behavior of the spectral bandwidth, and the angular spread of the nonlinear Compton radiation on the laser pulse duration. Furthermore, it is shown that the radiation reaction effects can be employed to control the electron dynamics via the nonlinear interplay between the Lorentz and radiation reaction forces. In particular, it is shown that an ultrarelativistic electron bunch colliding head- on with a strong bichromatic laser pulse can be deflected in a controllable way, by changing either the relative phase or the relative amplitude between the two frequency components of the bichromatic field.

  15. Study of performance of electronic dosemeters in continuous and pulsed X-radiation beams

    International Nuclear Information System (INIS)

    Personal radiation monitoring is a basic procedure to verify the compliance to regulatory requirements for radiological protection. Electronic personal dosimeters (EPD) based on solid state detectors have largely been used for personnel monitoring; including for pulsed radiation beams where their responses are not well known and deficiencies have been reported. In this work, irradiation conditions for testing the response of EPDs in both continuous and pulsed X-ray beams were studied to be established in a constant potential Seifert-Pantak and in a medical Pulsar 800 Plus VMI X-ray machines. Characterization of X-ray beams was done in terms of tube voltage, half-value layer, mean energy and air kerma rate. A Xi R/F Unfors solid state dosimeter used as reference for air kerma measurements was verified against a RC-6 and 10X6-6 Radical ionization chambers as far its metrological coherence. Rad-60 RADOS, PDM- 11 Aloka and EPD MK2 Thermo electron EPDs were selected to be tested in terms of relative intrinsic error and energy response in similar to IEC RQR, IEC RQA and ISO N reference radiations. Results demonstrated the reliability of the solid state Xi R/F Unfors dosimeter to be as reference dosimeter although its response was affected by heavily filtered beams. Results also showed that relative intrinsic errors in the response of the EPDs in terms of personal dose equivalent, Hp(10), were higher than the requirement established for continuous beams. In pulsed beams, some EPDs showed inadequate response and high relative intrinsic errors. This work stressed the need of performing additional checks for EPDs, besides the limited 137Cs beam calibration, before using them in pulsed X-ray beams. (author)

  16. Learning Boost C++ libraries

    CERN Document Server

    Mukherjee, Arindam

    2015-01-01

    If you are a C++ programmer who has never used Boost libraries before, this book will get you up-to-speed with using them. Whether you are developing new C++ software or maintaining existing code written using Boost libraries, this hands-on introduction will help you decide on the right library and techniques to solve your practical programming problems.

  17. Normal tissue tolerance to external beam radiation therapy: Skin

    International Nuclear Information System (INIS)

    Acute skin toxicity is frequent during radiation therapy and can lead to temporary arrest of the treatment. Chronic toxicity can occur and conduct to cosmetic problems. Alopecia is the most frequent toxicity concerning hair and is most of the time reversible. Several factors linked to patients influence skin toxicity, such as under-nutrition, old age, obesity, smoking, skin diseases, autoimmune diseases, failure of DNA reparation. Skin, hair and nail toxicities depend also on radiation schedule. Acute toxicity is greater when dose per fraction increases. Chronic and acute toxicities are more often when total dose increases. Under 45 Gy, the risk of severe skin toxicity is low, and begins above 50 Gy. Skin toxicity depends also on the duration of radiotherapy and split course schedules are associated with less toxicities. Irradiation surface seems to influence skin toxicity but interaction is more complex. Reirradiation is often feasible in case of cancer recurrence but with a risk of grade 3-4 toxicity above all in head and neck cancer. The benefit/risk ratio has to be always precisely evaluated. Permanent alopecia is correlated with the follicle dose. Modern techniques of radiation therapy allow to spare skin. (authors)

  18. A more robust boosting algorithm

    OpenAIRE

    Freund, Yoav

    2009-01-01

    We present a new boosting algorithm, motivated by the large margins theory for boosting. We give experimental evidence that the new algorithm is significantly more robust against label noise than existing boosting algorithm.

  19. Electron beam excitation of a CSRR loaded waveguide for Cherenkov radiation

    Science.gov (United States)

    Sharples, Emmy; Letizia, Rosa

    2015-09-01

    A novel metamaterial structure is presented for applications as a backward propagating Cherenkov source or Cherenkov detector. The structure comprises of a complementary split ring resonator (CSRR) metasurface loaded waveguide, which exhibits left handed behaviour between 5-6 GHz. When the left handed, TM-like mode couples with an incident electron beam, backward propagating Cherenkov radiation is observed. The structure is suitable for beam-based applications, exhibiting strong beam coupling parameters and significant excitation of longitudinal wakefields. Three dimensional particle in cell simulations are performed to identify a suitable beam for operation. High and low energy beams, with different bunch dimensions from the literature, are considered and compared to investigate the nature of the beam-wave interaction this structure can support, and to identify any required modification before beam tests can be performed. This structure can lead to new solutions for non-destructive beam diagnostics, wakefield acceleration and backward wave oscillators which can potentially be scaled to higher frequency ranges.

  20. Smith-Purcell radiation from a 50 MeV beam

    International Nuclear Information System (INIS)

    A 50 MeV electron beam and a 1 mm period, 5 degree blaze, echelle grating have been used to produce radiation in the mid-infrared spectral region. The emission is highly collimated and forward-directed. The intensity level in the few ps pulse (2 nJ/sr) indicates a degree of coherent enhancement

  1. Reflection of parametric X-ray radiation at the right angle to the particle beam

    International Nuclear Information System (INIS)

    The angular distribution (AD) of the yield in the reflection of parametric X-ray radiation (PXR), generated by relativistic particles in a crystal at the right angle to the particle beam, is considered theoretically. It is shown that the AD should have five singular points. 23 refs., 2 figs

  2. Cherenkov imaging during volumetric modulated arc therapy for real-time radiation beam tracking and treatment response monitoring

    Science.gov (United States)

    Andreozzi, Jacqueline M.; Zhang, Rongxiao; Glaser, Adam K.; Gladstone, David J.; Jarvis, Lesley A.; Pogue, Brian W.

    2016-03-01

    External beam radiotherapy utilizes high energy radiation to target cancer with dynamic, patient-specific treatment plans. The otherwise invisible radiation beam can be observed via the optical Cherenkov photons emitted from interaction between the high energy beam and tissue. Using a specialized camera-system, the Cherenkov emission can thus be used to track the radiation beam on the surface of the patient in real-time, even for complex cases such as volumetric modulated arc therapy (VMAT). Two patients undergoing VMAT of the head and neck were imaged and analyzed, and the viability of the system to provide clinical feedback was established.

  3. Transmissivities of radiation beams and particle beams in multicomponent mixed materials. 2. Finite Markov chain model

    International Nuclear Information System (INIS)

    This paper is a complement to an earlier paper on the transmissivity of beams in multi-component mixed materials of identical grain size and presents an analytical expression of transmissivity based on the finite Markov chain in the case of mixed materials of different grain sizes. The expression is represented by the flux vector and the response matrix obtained from the transition matrix. (author)

  4. Alanine Radiation Detectors in Therapeutic Carbon Ion Beams

    DEFF Research Database (Denmark)

    Herrmann, Rochus; Jäkel, Oliver; Palmans, Hugo;

        Radiotherapy with particles is getting more attention in Europe. New facilities for protons and heavier ions are finished, or near to the final status, some more are planed. Particle therapy with heavy ions is a challenge to dosimetry, since mixed particle fields occur in the peak region...... of the depth dose curves. Solid state detectors, such as diamond detectors, radiochromic films, TLDs and the amino acid alanine are used due to there good spatial resolution. If used in particle beams their response often exhibits a dependence on particle energy and type, so the acquired signal is not always...... proportional to absorbed dose. A model by Hansen and Olsen, based on the Track Structure Theory is available, which can predict the relative efficiency of some detectors, when the particle spectrum is known. For alanine detectors the model was successfully validated by Hansen and Olsen for several ion species...

  5. Electron beam radiation of unsaturated polyester-styrene systems

    International Nuclear Information System (INIS)

    Polyester resins prepared by mixing the unsaturated polyester and styrene with the weight ratio is 70 : 30 was irradiated using low energy electron beam. The influence of irradiation dose, composition and molecular-weight to the film properties were studied. Physical and mechanical such as hardness, abrasion resistence, tensile strength and elongation at break were evaluated. It was found that polyester film prepared from backbone base on isophthalic acid, fumaric acid, propylene glycol, diethyl glycol and glycerol, gave the best properties compared with others. At the dose of 100 kGy and dose rate of 26 kGy/sec., the gel-fraction was 93.1% tensile strength was about 440 Kg/cm2 and a hardeness of 4 H. (authors). 8 refs, 5 figs, 2 tabs

  6. Characteristics of the programme of dose calculation in the area of irregular entry fields of cobalt radiation beams

    International Nuclear Information System (INIS)

    The programme of calculating the doses in the areas of irregular entry fields of cobalt radiation beam is described. The calculations were carried out in a plane perpendicular to the axis of the beam (one or two opposite beams). The programme is written in the FORTRAN language and used in conversation mode in a set of Informatek minicomputer. (author)

  7. A novel method involving Matlab coding to determine the distribution of a collimated ionizing radiation beam

    Science.gov (United States)

    Ioan, M.-R.

    2016-08-01

    In ionizing radiation related experiments, precisely knowing of the involved parameters it is a very important task. Some of these experiments are involving the use of electromagnetic ionizing radiation such are gamma rays and X rays, others make use of energetic charged or not charged small dimensions particles such are protons, electrons, neutrons and even, in other cases, larger accelerated particles such are helium or deuterium nuclei are used. In all these cases the beam used to hit an exposed target must be previously collimated and precisely characterized. In this paper, a novel method to determine the distribution of the collimated beam involving Matlab coding is proposed. The method was implemented by using of some Pyrex glass test samples placed in the beam where its distribution and dimension must be determined, followed by taking high quality pictures of them and then by digital processing the resulted images. By this method, information regarding the doses absorbed in the exposed samples volume are obtained too.

  8. Calculation of synchrotron radiation from high intensity electron beam at eRHIC

    Energy Technology Data Exchange (ETDEWEB)

    Jing Y.; Chubar, O.; Litvinenko, V.

    2012-05-20

    The Electron-Relativistic Heavy Ion Collider (eRHIC) at Brookhaven National Lab is an upgrade project for the existing RHIC. A 30 GeV energy recovery linac (ERL) will provide a high charge and high quality electron beam to collide with proton and ion beams. This will improve the luminosity by at least 2 orders of magnitude. The synchrotron radiation (SR) from the bending magnets and strong quadrupoles for such an intense beam could be penetrating the vacuum chamber and producing hazards to electronic devices and undesired background for detectors. In this paper, we calculate the SR spectral intensity, power density distributions and heat load on the chamber wall. We suggest the wall thickness required to stop the SR and estimate spectral characteristics of the residual and scattered background radiation outside the chamber.

  9. Photon beam audits for radiation therapy clinics: A pilot mailed dosemeter study in Turkey

    International Nuclear Information System (INIS)

    A thermoluminescent dosemeter (TLD) mailed dose audit programme was performed at five radiotherapy clinics in Turkey. The intercomparison was organised by the Univ. of Wisconsin Radiation Calibration Laboratory (UWRCL), which was responsible for the technical aspects of the study including reference irradiations, distribution, collection and evaluation. The purpose of these audits was to perform an independent dosimetry check of the radiation beams using TLDs sent by mail. Acrylic holders, each with five TLD chips inside and instructions for their irradiation to specified absorbed dose to water of 2 Gy, were mailed to all participating clinics. TLD irradiations were performed with a 6 MV linear accelerator and 60Co photon beams. The deviations from the TL readings of UWRCL were calculated. Discrepancies inside the limits of ±5 % between the participant-stated dose, and the TLD-measured dose were considered acceptable. One out of 10 beams checked was outside this limit, with a difference of 5.8 %. (authors)

  10. Ion beam induced charge and cathodoluminescence imaging of response uniformity of CVD diamond radiation detectors

    CERN Document Server

    Sellin, P J; Galbiati, A; Maghrabi, M; Townsend, P D

    2002-01-01

    The uniformity of response of CVD diamond radiation detectors produced from high quality diamond film, with crystallite dimensions of >100 mu m, has been studied using ion beam induced charge imaging. A micron-resolution scanning alpha particle beam was used to produce maps of pulse height response across the device. The detectors were fabricated with a single-sided coplanar electrode geometry to maximise their sensitivity to the surface region of the diamond film where the diamond crystallites are highly ordered. High resolution ion beam induced charge images of single crystallites were acquired that demonstrate variations in intra-crystallite charge transport and the termination of charge transport at the crystallite boundaries. Cathodoluminescence imaging of the same crystallites shows an inverse correlation between the density of radiative centres and regions of good charge transport.

  11. Development and application of a dosimetric methodology of therapeutic X radiation beams using a tandem system

    International Nuclear Information System (INIS)

    In radiotherapy the use of orthovoltage X radiation beams is still recommended; to obtain satisfactory results, a periodic control is necessary to check the performance of the ionization chambers and the radiation beams characteristics. This control is performed by using standard dosimetric procedures, as for example the determination of half-value layers and the absorbed dose rates. A Tandem system was established in this work using a pair of ionization chambers (a thimble type and a superficial type) used for measures in a medical institution, in substitution to the routine conventional procedure of determination of half-value layers using absorbers. The results obtained show the application of this method in dosimetric procedures of orthovoltage beams (radiotherapy) as a complement for a quality control program. (author)

  12. Study of filamentation dynamics of ultrashort laser radiation in air: beam diameter effect

    International Nuclear Information System (INIS)

    A single filamentation of femtosecond gigawatt laser radiation with a millimeter-size aperture upon collimated and sharply focused propagation in atmospheric air at 800 nm and 400 nm wavelengths is studied both theoretically and experimentally. The influence of beam initial radius on the parameters of the forming filament is analyzed. Three filament parameters, namely, start coordinate, filament length, and longitudinal continuity are considered. We report that unlike Marburger’s formula the single filamentation onset reveals marked nonquadratic dependence on the laser beam radius providing the same initial pulse power. Additionally, for sharply focused radiation the minor dependence of the filament length on the laser beam diameter at the constant initial pulse intensity was experimentally revealed. (paper)

  13. Observation of Spontaneous Emitted X-ray Betatron Radiation in Beam-Plasma Interactions

    International Nuclear Information System (INIS)

    An experiment is being carried out at the Stanford Linear Accelerator Center (SLAC) to see if an ion channel can wiggle a beam of ultra-relativistic electrons to produce x-ray radiation. The goal is to create an intense source of undulator radiation using a plasma wiggler in the 1-10 KeV range and also to determine the suitability of such an electrostatic wiggler to create a coherent beam of x-rays via the ion channel laser mechanism [1]. Here we give some of the scaling laws for the power and frequency distribution of the spontaneous emission from sending an electron beam through such an ion channel. Some initial experimental observations are also presented

  14. The NASA Space Radiation Laboratory at Brookhaven National Laboratory: Preparation and delivery of ion beams for space radiation research

    International Nuclear Information System (INIS)

    The NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL) was commissioned in October 2002 and became operational in July 2003. The NSRL was constructed in collaboration with NASA for the purpose of performing space radiation research as part of the NASA space program. The NSRL can accept a wide variety of ions from BNL's Collider Accelerator Department (CAD) Booster accelerator. These ion beams are extracted from the accelerator with kinetic energies ranging from 0.05 to 3 GeV/nucleon. Many different beam conditions have been produced for experiments at NSRL. The facilities at BNL and the design of the NSRL facility permit a wide variety of beams to be produced with a great degree of flexibility in the delivery of ion beams to experiments. In this report we will describe the facility and its performance over the eight experimental run periods that have taken place since it became operational. We will also describe the current and future capabilities of the NSRL.

  15. Spatial resolution in optical transition radiation (OTR) beam diagnostics

    International Nuclear Information System (INIS)

    An evaluation of the OTR single particle image dimension is obtained using diffraction theory based on a realistic description of the radiation source. This approach allows the analysis of the effect of the finite size of the emitting screen and of the imaging system. The role of practical experimental conditions in treating the intensity tail problem is estimated. It is shown that by exploiting the polarization properties of OTR, a considerable enhancement in the spatial resolution can be achieved, which becomes very similar to that of a standard point source

  16. External beam radiation for retinoblastoma: Results, patterns of failure, and a proposal for treatment guidelines

    International Nuclear Information System (INIS)

    Purpose: To analyze treatment results and patterns of failure following external beam radiation for retinoblastoma and propose treatment guidelines according to specific clinical variables. Methods and Materials: We analyzed 27 patients (34 eyes) with retinoblastoma who received external beam radiation as initial treatment at Hahnemann University Hospital from October 1980 to December 1991 and have been followed for at least 1 year. Of the 34 eyes, 14 were Groups I-II (Reese-Ellsworth classification), 7 were Group III, and 13 were Groups IV-V. Doses ranged from 34.5-49.5 Gy (mean 44.3 Gy, median 45 Gy) in 1.5-2.0 Gy fractions generally delivered through anterior and lateral wedged pair fields. Results: At a mean follow up of 35.2 months (range 12-93 months), local tumor control was obtained in 44% (15 out of 34) of eyes with external beam radiation alone. Salvage therapy (plaque brachytherapy, cryotherapy, and/or photocoagulation) controlled an additional 10 eyes (29.5%), so that overall ocular survival has been 73.5%. Local tumor control with external beam radiotherapy alone was obtained in 78.5% (11 out of 14) of eyes in Groups I-II, but in only 20% (4 out of 20) of eyes in Groups III-V. A total of 67 existing tumors were identified prior to treatment in the 34 treated eyes and local control with external beam radiation alone was obtained in 87% (46 out of 53) of tumors measuring 15 mm or less and in 50% (7 out of 14) of tumors measuring more than 15 mm. When analyzing patterns of failure in the 19 eyes that relapsed, a total of 28 failure sites were identified and consisted of progression of vitreous seeds in seven instances (25% of failure sites) recurrences from previously existing tumors in 10 instances (36% of failure sites) and development of new tumors in previously uninvolved retina in 11 instances (39% of failure sites). Conclusions: 1) We find that external beam radiation to a dose of 45 Gy in fractions of 1.5 to 2.0 Gy provides adequate tumor control

  17. Dynamic optical modulation of an electron beam on a photocathode RF gun: Toward intensity-modulated radiation therapy (IMRT)

    International Nuclear Information System (INIS)

    In intensity-modulated radiation therapy (IMRT), the aim is to deliver reduced doses of radiation to normal tissue. As a step toward IMRT, we examined dynamic optical modulation of an electron beam produced by a photocathode RF gun. Images on photomasks were transferred onto a photocathode by relay imaging. The resulting beam was controlled by a remote mirror. The modulated electron beam maintained its shape on acceleration, had a fine spatial resolution, and could be moved dynamically by optical methods

  18. Dynamic optical modulation of an electron beam on a photocathode RF gun: Toward intensity-modulated radiation therapy (IMRT)

    Science.gov (United States)

    Kondoh, Takafumi; Kashima, Hiroaki; Yang, Jinfeng; Yoshida, Yoichi; Tagawa, Seiichi

    2008-10-01

    In intensity-modulated radiation therapy (IMRT), the aim is to deliver reduced doses of radiation to normal tissue. As a step toward IMRT, we examined dynamic optical modulation of an electron beam produced by a photocathode RF gun. Images on photomasks were transferred onto a photocathode by relay imaging. The resulting beam was controlled by a remote mirror. The modulated electron beam maintained its shape on acceleration, had a fine spatial resolution, and could be moved dynamically by optical methods.

  19. Metrology and quality of radiation therapy dosimetry of electron, photon and epithermal neutron beams

    International Nuclear Information System (INIS)

    In radiation therapy using electron and photon beams the dosimetry chain consists of several sequential phases starting by the realisation of the dose quantity in the Primary Standard Dosimetry Laboratory and ending to the calculation of the dose to a patient. A similar procedure can be described for the dosimetry of epithermal neutron beams in boron neutron capture therapy (BNCT). To achieve the required accuracy of the dose delivered to a patient the quality of all steps in the dosimetry procedure has to be considered. This work is focused on two items in the dosimetry chains: the determination of the dose in the reference conditions and the evaluation of the accuracy of dose calculation methods. The issues investigated and discussed in detail are: a)the calibration methods of plane parallel ionisation chambers used in electron beam dosimetry, (b) the specification of the critical dosimetric parameter i.e. the ratio of stopping powers for water to air, (S I ?)waterair, in photon beams, (c) the feasibility of the twin ionization chamber technique for dosimetry in epithermal neutron beams applied to BNCT and (d) the determination accuracy of the calculated dose distributions in phantoms in electron, photon, and epithermal neutron beams. The results demonstrate that up to a 3% improvement in the consistency of dose determinations in electron beams is achieved by the calibration of plane parallel ionisation chambers in high energy electron beams instead of calibrations in 60Co gamma beams. In photon beam dosimetry (S I ?)waterair can be determined with an accuracy of 0.2% using the percentage dose at the 10 cm depth, %dd(10), as a beam specifier. The use of %odd(10) requires the elimination of the electron contamination in the photon beam. By a twin ionisation chamber technique the gamma dose can be determined with uncertainty of 6% (1 standard deviation) and the total neutron dose with an uncertainty of 15 to 20% (1 standard deviation). To improve the accuracy of

  20. Metrology and quality of radiation therapy dosimetry of electron, photon and epithermal neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Kosunen, A

    1999-08-01

    In radiation therapy using electron and photon beams the dosimetry chain consists of several sequential phases starting by the realisation of the dose quantity in the Primary Standard Dosimetry Laboratory and ending to the calculation of the dose to a patient. A similar procedure can be described for the dosimetry of epithermal neutron beams in boron neutron capture therapy (BNCT). To achieve the required accuracy of the dose delivered to a patient the quality of all steps in the dosimetry procedure has to be considered. This work is focused on two items in the dosimetry chains: the determination of the dose in the reference conditions and the evaluation of the accuracy of dose calculation methods. The issues investigated and discussed in detail are: a)the calibration methods of plane parallel ionisation chambers used in electron beam dosimetry, (b) the specification of the critical dosimetric parameter i.e. the ratio of stopping powers for water to air, (S I ?){sup water} {sub air}, in photon beams, (c) the feasibility of the twin ionization chamber technique for dosimetry in epithermal neutron beams applied to BNCT and (d) the determination accuracy of the calculated dose distributions in phantoms in electron, photon, and epithermal neutron beams. The results demonstrate that up to a 3% improvement in the consistency of dose determinations in electron beams is achieved by the calibration of plane parallel ionisation chambers in high energy electron beams instead of calibrations in {sup 60}Co gamma beams. In photon beam dosimetry (S I ?){sup water} {sub air} can be determined with an accuracy of 0.2% using the percentage dose at the 10 cm depth, %dd(10), as a beam specifier. The use of %odd(10) requires the elimination of the electron contamination in the photon beam. By a twin ionisation chamber technique the gamma dose can be determined with uncertainty of 6% (1 standard deviation) and the total neutron dose with an uncertainty of 15 to 20% (1 standard deviation

  1. Efficient, radiation-hardened, 800-keV neutral beam injection system

    International Nuclear Information System (INIS)

    Recent advances and new concepts in negative ion generation, transport, acceleration, and neutrailzation make it appear likely that an efficient, radiation-hardened neutral beam injection system could be developed in time for the proposed FED-A tokamak. These new developments include the operation of steady-state H- ion sources at over 5 A per meter of source length, the concept of using strong-focussing electrostatic structures for low-gradient dc acceleration of high-current sheet beams of negative ions and the transport of these beams around corners, and the development of powerful oxygen-iodine chemical lasers which will make possible the efficient conversion of the negative ions to neutrals using a photodetachment scheme in which the ion beam passes through the laser cavity

  2. Time-Resolved Emittance Characterization of an Induction Linac Beam using Optical Transition Radiation

    CERN Document Server

    Le Sage, G P

    2002-01-01

    An induction linac is used by Lawrence Livermore National Laboratory to perform radiographic testing at the Flash X-ray Radiography facility. Emittance characterization is important since x-ray spot size impacts the resolution of shadow-graphs. Due to the long pulse length, high current, and beam energy, emittance measurement using Optical Transition Radiation is an attractive alternative for reasons that will be described in the text. The utility of OTR-based emittance measurement has been well demonstrated for both RF and induction linacs. We describe the time-resolved emittance characterization of an induction linac electron beam. We have refined the optical collection system for the induction linac application, and have demonstrated a new technique for probing the divergence of a subset of the beam profile. The experimental apparatus, data reduction, and conclusions will be presented. Additionally, a new scheme for characterizing the correlation between beam divergence and spatial coordinates within the b...

  3. A high rate transition radiation detector for particle identification in a hadron beam

    International Nuclear Information System (INIS)

    A Transition Radiation Detector (TRD) was built for the purpose of tagging beam particles in a high rate (∼2 MHz) 250 GeV/c hadron beam during data taking for Experiment 769 at Fermilab. The availability of a good ''tool kit'', including a Monte Carlo program which could reliably predict the detector performance, made it possible to design and build the TRD in approximately one year. Pion or proton samples, each with a small contamination due to the other, could be selected with high efficiency by making cuts on the number of planes of the TRD registering hits for each incident beam particle. The detector is expected to work well to separate kaons from pions in the 500 GeV/c negative beam for E791. 15 refs., 8 figs., 1 tab

  4. Electromagnetic Coupling Between High Intensity LHC Beams and the Synchrotron Radiation Monitor Light Extraction System

    CERN Document Server

    Andreazza, W; Bravin, E; Caspers, F; Garlasch`e, M; Gras, J; Goldblatt, A; Lefevre, T; Jones, R; Metral, E; Nosych, A; Roncarolo_, F; Salvant, B; Trad, G; Veness, R; Vollinger, C; Wendt, M

    2013-01-01

    The CERN LHC is equipped with two Synchrotron Radiation Monitor (BSRT) systems used to characterise transverse and longitudinal beam distributions. Since the end of the 2011 LHC run the light extraction system, based on a retractable mirror, has suffered deformation and mechanical failure that is correlated to the increase in beam intensity. Temperature probes have associated these observations to a strong heating of the mirror support with a dependence on the longitudinal bunch length and shape, indicating the origin as electromagnetic coupling between the beam and the structure. This paper combines all this information with the aim of characterising and improving the system in view of its upgrade during the current LHC shutdown. Beam-based observations are presented along with electromagnetic and thermomechanical simulations and complemented by laboratory measurements, including the study of the RF properties of different mirror bulk and coating materials.

  5. Optimization of combined electron and photon beams for breast cancer

    International Nuclear Information System (INIS)

    Recently, intensity-modulated radiation therapy and modulated electron radiotherapy have gathered a growing interest for the treatment of breast and head and neck tumours. In this work, we carried out a study to combine electron and photon beams to achieve differential dose distributions for multiple target volumes simultaneously. A Monte Carlo based treatment planning system was investigated, which consists of a set of software tools to perform accurate dose calculation, treatment optimization, leaf sequencing and plan analysis. We compared breast treatment plans generated using this home-grown optimization and dose calculation software for different treatment techniques. Five different planning techniques have been developed for this study based on a standard photon beam whole breast treatment and an electron beam tumour bed cone down. Technique 1 includes two 6 MV tangential wedged photon beams followed by an anterior boost electron field. Technique 2 includes two 6 MV tangential intensity-modulated photon beams and the same boost electron field. Technique 3 optimizes two intensity-modulated photon beams based on a boost electron field. Technique 4 optimizes two intensity-modulated photon beams and the weight of the boost electron field. Technique 5 combines two intensity-modulated photon beams with an intensity-modulated electron field. Our results show that technique 2 can reduce hot spots both in the breast and the tumour bed compared to technique 1 (dose inhomogeneity is reduced from 34% to 28% for the target). Techniques 3, 4 and 5 can deliver a more homogeneous dose distribution to the target (with dose inhomogeneities for the target of 22%, 20% and 9%, respectively). In many cases techniques 3, 4 and 5 can reduce the dose to the lung and heart. It is concluded that combined photon and electron beam therapy may be advantageous for treating breast cancer compared to conventional treatment techniques using tangential wedged photon beams followed by a boost

  6. Quantum radiation reaction in head-on laser-electron beam interaction

    CERN Document Server

    Vranic, Marija; Fonseca, Ricardo A; Silva, Luis O

    2015-01-01

    In this paper, we investigate the evolution of the energy spread and the divergence of electron beams while they interact with different laser pulses at intensities where quantum effects and radiation reaction are of relevance. The interaction is modeled with a QED-PIC code and the results are compared with those obtained with a standard PIC code with the addition of a classical radiation reaction module and with theoretical predictions. While classical radiation reaction is a continuous process, in QED, radiation emission is stochastic. The two pictures reconcile in the limit when the emitted photons energy is small compared to the energy of the emitting electrons. The energy spread of the electron distribution function always tends to decrease with classical radiation reaction, whereas the stochastic QED emission can also enlarge it. These two tendencies compete in the QED-dominated regime. Our analysis, supported by the QED module, reveals an upper limit to the maximal attainable energy spread due to stoch...

  7. Detector Response and Beam Line Transmission Measurements with Far-Infrared Radiation

    CERN Document Server

    Grimm, O; Fröhlich, L

    2005-01-01

    Various activities at the TTF linear accelerator at DESY, Hamburg, that drives the VUV-FEL are geared towards measuring the longitudinal charge distribution of electron bunches with coherent far-infrared radiation. Examples are beam lines transporting synchrotron or transition radiation to interferometers mounted inside or outside the tunnel, and studies of single-shot grating spectrometers. All such approaches require a good understanding of the radiation generation and transport mechanism and of the detector characteristics to extract useful information on the charge distribution. Simulations and measurements of the expected transverse intensity distribution and polarization of synchrotron radiation emitted at the first bunch compressor of TTF have been performed. The transverse intensity scanning provided for the first time at DESY a visual image of the footprint of terahertz radiation. Detector response measurements have been performed at the FELIX facility, Netherlands, for wavelengths between 100-160 mi...

  8. Effect of electron-beam radiation on graphite epoxy composites

    International Nuclear Information System (INIS)

    Specimens of unidirectional graphite/epoxy laminates were irradiated by 10-MeV electrons up to a total dose of 5000 Mrads at 50, 150, and 250 C and then tested mechanically to determine their flexural and interlaminar shear strengths. The radiation-generated volatile products and the components extracted by a solvent from the irradiated specimens were analyzed by gas-chromatographic and mass spectrometric techniques; the degradation of the matrix resin (bisphenol based epoxy) was characterized by FT-IR spectroscopy. It is found that the flexural strength of the specimens irradiated in air decreases with increasing dose. The flexural strength of the irradiated specimens, however, can be almost completely restored through a thermal cycling treatment. It is also shown that the degradation of the matrix increases with the irradiation dose. 9 references

  9. Normal tissue tolerance to external beam radiation therapy: Peripheral nerves

    International Nuclear Information System (INIS)

    Plexopathies and peripheral neuropathies appear progressively and with several years delay after radiotherapy. These lesions are observed principally after three clinical situations: supraclavicular and axillar irradiations for breast cancer, pelvic irradiations for various pathologies and limb irradiations for soft tissue sarcomas. Peripheral nerves and plexus (brachial and lumbosacral) are described as serial structures and are supposed to receive less than a given maximum dose linked to the occurrence of late injury. Literature data, mostly ancient, define the maximum tolerable dose to a threshold of 60 Gy and highlight also a great influence of fractionation and high fraction doses. For peripheral nerves, most frequent late effects are pain with significant differences of occurrence between 50 and 60 Gy. At last, associated pathologies (diabetes, vascular pathology, neuropathy) and associated treatments have probably to be taken into account as additional factors, which may increase the risk of these late radiation complications. (authors)

  10. Beam orientation optimization for intensity modulated radiation therapy using adaptive l2,1-minimization

    Science.gov (United States)

    Jia, Xun; Men, Chunhua; Lou, Yifei; Jiang, Steve B.

    2011-10-01

    Beam orientation optimization (BOO) is a key component in the process of intensity modulated radiation therapy treatment planning. It determines to what degree one can achieve a good treatment plan in the subsequent plan optimization process. In this paper, we have developed a BOO algorithm via adaptive l2, 1-minimization. Specifically, we introduce a sparsity objective function term into our model which contains weighting factors for each beam angle adaptively adjusted during the optimization process. Such an objective function favors a small number of beam angles. By optimizing a total objective function consisting of a dosimetric term and the sparsity term, we are able to identify unimportant beam angles and gradually remove them without largely sacrificing the dosimetric objective. In one typical prostate case, the convergence property of our algorithm, as well as how beam angles are selected during the optimization process, is demonstrated. Fluence map optimization (FMO) is then performed based on the optimized beam angles. The resulting plan quality is presented and is found to be better than that of equiangular beam orientations. We have further systematically validated our algorithm in the contexts of 5-9 coplanar beams for five prostate cases and one head and neck case. For each case, the final FMO objective function value is used to compare the optimized beam orientations with the equiangular ones. It is found that, in the majority of cases tested, our BOO algorithm leads to beam configurations which attain lower FMO objective function values than those of corresponding equiangular cases, indicating the effectiveness of our BOO algorithm. Superior plan qualities are also demonstrated by comparing DVH curves between BOO plans and equiangular plans.

  11. Pertinence analysis of intensity-modulated radiation therapy dosimetry error and parameters of beams

    International Nuclear Information System (INIS)

    Objective: To study the relationship between parameter settings in the intensity-modulated radiation therapy (IMRT) planning in order to explore the effect of parameters on absolute dose verification. Methods: Forty-three esophageal carcinoma cases were optimized with Pinnacle 7.6c by experienced physicist using appropriate optimization parameters and dose constraints with a number of iterations to meet the clinical acceptance criteria. The plans were copied to water-phantom, 0.13 cc ion Farmer chamber and DOSE1 dosimeter was used to measure the absolute dose. The statistical data of the parameters of beams for the 43 cases were collected, and the relationships among them were analyzed. The statistical data of the dosimetry error were collected, and comparative analysis was made for the relation between the parameters of beams and ion chamber absolute dose verification results. Results: The parameters of beams were correlated among each other. Obvious affiliation existed between the dose accuracy and parameter settings. When the beam segment number of IMRT plan was more than 80, the dose deviation would be greater than 3%; however, if the beam segment number was less than 80, the dose deviation was smaller than 3%. When the beam segment number was more than 100, part of the dose deviation of this plan was greater than 4%. On the contrary, if the beam segment number was less than 100, the dose deviation was smaller than 4% definitely. Conclusions: In order to decrease the absolute dose verification error, less beam angles and less beam segments are needed and the beam segment number should be controlled within the range of 80. (authors)

  12. Integrating and automating the software environment for the Beam and Radiation Monitoring for CMS

    CERN Document Server

    Filyushkina, Olga; Juslin, J

    2010-01-01

    The real-time online visualization framework used by the Beam and Radiation Monitoring group at the Compact Muon Solenoid at Large Hadron Collider, CERN. The purpose of the visualization framework is to provide real-time diagnostic of beam conditions, which defines the set of the requirements to be met by the framework. Those requirements include data quality assurance, vital safety issues, low latency, data caching, etc. The real-time visualization framework is written in the Java programming language and based on JDataViewer--a plotting package developed at CERN. At the current time the framework is run by the Beam and Radiation Monitoring, Pixel, Tracker groups, Run Field Manager and others. It contributed to real-time data analysis during 2009-2010 runs as a stable monitoring tool. The displays reflect the beam conditions in a real-time with the low latency level, thus it is the first place at the CMS detector where the beam collisions are observed.

  13. Use of XR-QA2 radiochromic films for quantitative imaging of a synchrotron radiation beam

    International Nuclear Information System (INIS)

    In the framework of an ongoing project, promoted by INFN, at the SYRMEP beamline of the ELETTRA synchrotron radiation facility (Trieste, Italy) for phase-contrast breast X-ray computed tomography, the assessment of the dose to the breast is one of the issues, requiring the determination of the distribution of X-ray incident photon fluence. This work investigates the use of XR-QA2 radiochromic films for quantitative imaging of the synchrotron radiation (SR) beam. XR-QA2 films were irradiated in a plane transverse to the beam axis, with a monochromatic beam of energy of 28, 35, 38 or 40 keV. The response of the radiochromic film was calibrated in terms of average air kerma measured with an ionization chamber. The net reflectance of the exposed film was then converted to photon fluence per unit air kerma (mm−2mGy−1). The SR beam profile was acquired also with a scintillator (GOS) based, fiber optic coupled CCD camera as well as with a scintillator based flat panel detector. Horizontal and vertical line profiles acquired with the radiochromic films show the 2D distribution of the beam intensity, with variations in the order of 15–20% in the horizontal direction. The response of the radiochromic film is comparable to that of the other imaging detectors, within less than 5% variation

  14. Comprehensive MRI simulation methodology using a dedicated MRI scanner in radiation oncology for external beam radiation treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Paulson, Eric S., E-mail: epaulson@mcw.edu [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 and Department of Radiology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 (United States); Erickson, Beth; Schultz, Chris; Allen Li, X. [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 (United States)

    2015-01-15

    Purpose: The use of magnetic resonance imaging (MRI) in radiation oncology is expanding rapidly, and more clinics are integrating MRI into their radiation therapy workflows. However, radiation therapy presents a new set of challenges and places additional constraints on MRI compared to diagnostic radiology that, if not properly addressed, can undermine the advantages MRI offers for radiation treatment planning (RTP). The authors introduce here strategies to manage several challenges of using MRI for virtual simulation in external beam RTP. Methods: A total of 810 clinical MRI simulation exams were performed using a dedicated MRI scanner for external beam RTP of brain, breast, cervix, head and neck, liver, pancreas, prostate, and sarcoma cancers. Patients were imaged in treatment position using MRI-optimal immobilization devices. Radiofrequency (RF) coil configurations and scan protocols were optimized based on RTP constraints. Off-resonance and gradient nonlinearity-induced geometric distortions were minimized or corrected prior to using images for RTP. A multidisciplinary MRI simulation guide, along with window width and level presets, was created to standardize use of MR images during RTP. A quality assurance program was implemented to maintain accuracy and repeatability of MRI simulation exams. Results: The combination of a large bore scanner, high field strength, and circumferentially wrapped, flexible phased array RF receive coils permitted acquisition of thin slice images with high contrast-to-noise ratio (CNR) and image intensity uniformity, while simultaneously accommodating patient setup and immobilization devices. Postprocessing corrections and alternative acquisition methods were required to reduce or correct off-resonance and gradient nonlinearity induced geometric distortions. Conclusions: The methodology described herein contains practical strategies the authors have implemented through lessons learned performing clinical MRI simulation exams. In

  15. Comprehensive MRI simulation methodology using a dedicated MRI scanner in radiation oncology for external beam radiation treatment planning

    International Nuclear Information System (INIS)

    Purpose: The use of magnetic resonance imaging (MRI) in radiation oncology is expanding rapidly, and more clinics are integrating MRI into their radiation therapy workflows. However, radiation therapy presents a new set of challenges and places additional constraints on MRI compared to diagnostic radiology that, if not properly addressed, can undermine the advantages MRI offers for radiation treatment planning (RTP). The authors introduce here strategies to manage several challenges of using MRI for virtual simulation in external beam RTP. Methods: A total of 810 clinical MRI simulation exams were performed using a dedicated MRI scanner for external beam RTP of brain, breast, cervix, head and neck, liver, pancreas, prostate, and sarcoma cancers. Patients were imaged in treatment position using MRI-optimal immobilization devices. Radiofrequency (RF) coil configurations and scan protocols were optimized based on RTP constraints. Off-resonance and gradient nonlinearity-induced geometric distortions were minimized or corrected prior to using images for RTP. A multidisciplinary MRI simulation guide, along with window width and level presets, was created to standardize use of MR images during RTP. A quality assurance program was implemented to maintain accuracy and repeatability of MRI simulation exams. Results: The combination of a large bore scanner, high field strength, and circumferentially wrapped, flexible phased array RF receive coils permitted acquisition of thin slice images with high contrast-to-noise ratio (CNR) and image intensity uniformity, while simultaneously accommodating patient setup and immobilization devices. Postprocessing corrections and alternative acquisition methods were required to reduce or correct off-resonance and gradient nonlinearity induced geometric distortions. Conclusions: The methodology described herein contains practical strategies the authors have implemented through lessons learned performing clinical MRI simulation exams. In

  16. Radiation quality and ion-beam therapy: understanding the users' needs

    International Nuclear Information System (INIS)

    Ion-beam therapy faces a growing demand of tools able to map radiation quality within the irradiated volume. Although analytical computations and simulations provide useful estimations of dose and radiation quality, the direct measure of those parameters would improve ion-beam therapy in particular when deep-seated tumours are irradiated, tissue composition and density are variable or organs at risk are near the tumour. Several ion-beam therapy facilities are studying detectors and procedures for measuring the radiation quality on a microdosimetric as well as a nanodosimetric scale. Simplicity and miniaturisation of the devices are essential for measurements first in phantoms and thereafter during therapy, particularly for intra-cavity detectors. MedAustron is studying solid-state detectors based on a single crystal chemical vapour deposition diamond. In collaboration with Italian National Institute for Nuclear Physics (INFN), Tor Vergata and Legnaro; INFN-microdosimetry and track structure project; Austrian Institute of Technology, Vienna; and Italian National agency for new technologies, energy and sustainable economic development, Rome, prototypes have been developed to characterise radiation quality in sizes equivalent to one micrometre of biological tissue. (authors)

  17. Role of the rise rate of beam current in the microwave radiation of vircator

    Science.gov (United States)

    Li, Limin; Cheng, Guoxin; Zhang, Le; Ji, Xiang; Chang, Lei; Xu, Qifu; Liu, Lie; Wen, Jianchun; Li, Chuanlu; Wan, Hong

    2011-04-01

    In this paper, the effect of the rise rate of beam current on the microwave radiation of a virtual cathode oscillator (vircator) is presented. Interestingly, it was observed that the rise rate of the beam current increased as the pulse shot proceeded, which is accompanied by the decrease in microwave power. By comparing the experimental results of two cathode materials (carbon fiber and stainless steel), it was found that the above behavior is independent of the cathode materials. The ion flow, induced by the repetitive action of beam electrons with the anode grid, directly affects the development of beam current. A twice-increased process of ion flow was observed, and there are two factors involved in this process, namely, the reflection of electrons between the cathode and virtual cathode and the effect of one-time bombardment of electron beam. After the irradiation of pulsed electron beam, some microprotrusions toward the cathode appeared on the anode surface, with a quasiperiodic structure. The appearance of ion flow, as the anode plasma forms, increases the beam current and enhances the beam current density. The anode plasma is generated relatively easily as the shot test proceeds, due to the aging of anode grid, which allows the possibility of the decrease in the microwave power. As the pulse shot proceeds, the changes in the rise rate of beam current are closely related to the aging process of anode surface. Therefore, the further enhancement of vircator efficiency needs to lengthen the lifetime of anode, besides the optimization of explosive emission cathodes.

  18. Online Gradient Boosting

    OpenAIRE

    Beygelzimer, Alina; Hazan, Elad; Kale, Satyen; Luo, Haipeng

    2015-01-01

    We extend the theory of boosting for regression problems to the online learning setting. Generalizing from the batch setting for boosting, the notion of a weak learning algorithm is modeled as an online learning algorithm with linear loss functions that competes with a base class of regression functions, while a strong learning algorithm is an online learning algorithm with convex loss functions that competes with a larger class of regression functions. Our main result is an online gradient b...

  19. Local tumor control and cosmetic outcome following breast-conserving surgery and radiation up to a total dose of 56 Gy without boost in breast cancer patients; Lokale Tumorkontrolle und kosmetisches Ergebnis nach brusterhaltender Operation und Strahlentherapie bis 56 Gy Gesamtdosis ohne Boost beim Mammakarzinom

    Energy Technology Data Exchange (ETDEWEB)

    Bayerl, A. [Abteilung fuer Radioonkologie und Strahlentherapie Wiener Neustadt (Austria); Technische Univ. Muenchen (Germany). Inst. und Poliklinik fuer Strahlentherapie und Radiologische Onkologie; Frank, D.; Lenz, A.; Feldmann, H.J.; Molls, M. [Technische Univ. Muenchen (Germany). Inst. und Poliklinik fuer Strahlentherapie und Radiologische Onkologie; Hoess, C. [Technische Univ. Muenchen (Germany). Frauenklinik und Poliklinik; Lukas, P. [Universitaetsklinik fuer Strahlentherapie und Radioonkologie, Innsbruck (Austria)

    2001-01-01

    Purpose: To evaluate overall survival, local tumor control and cosmetic outcome after breast-conserving surgery followed by radiotherapy without boost irradiation. Patients and Methods: In a retrospective study 270 breast cancer patients were treated with breast conserving surgery combined with a homogenous radiation of the tumor bearing breast up to a total dose of 56 Gy without local boost irradiation. Mean follow-up was 48 months. Local tumor control, side effects, cosmetic results and contentment with treatment were assessed using physical examinations and interviews based on a standardized questionnaire. Results: Cause-specific survival at 5 years after treatment was 88.3%, actuarial disease-free survival at 5 years was 76.1%. Within 23 to 78 months after treatment 12 patients suffered from ipsilateral breast recurrence. The actuarial freedom from local recurrence (single tumor manifestation) was 96.8% at 5 years after treatment, 89% at 10 years. The occurrence of local failures was not significantly correlated to tumor size, margins, grading, nodal status, age or lymphangiosis. 15.6% of the patients developed distant metastases. In all patients treatment was performed without interruption. Side effects were predominantly of mild degree, no severe side effects were detected. 73% of physicians and 81% of patients scored their cosmetic outcome as excellent or good. 93% of patients would again decide in favor of this procedure. Whereas, use of adjuvant chemotherapy as well as subcutaneous reconstruction of breast tissue did not significantly affect breast cosmesis, analysis demonstrated impaired cosmetic results related to a larger breast size. Conclusion: The data of this study show that tumor control achieved by breast conserving surgery in combination with a radiation technique up to a total dose of 56 Gy which omits boost irradiation is within the range of literature data. Side effects of the therapy were tolerable. The treatment displayed a good

  20. Irradiation of 135 MeV/u carbon and neon beams for studies of radiation biology

    International Nuclear Information System (INIS)

    A heavy ion irradiation system was designed and constructed at RIKEN ring cyclotron facility for studies of radiation physics and radiation biology. Carbon and neon beams of 135 MeV/u were firstly used for the experiments. A pair of wobbler magnets and a scatterer were used for obtaining the uniform radiation field of about 10 cm in diameter. A parallel plate ionization chamber was used for dose monitoring. A range shifter was used for degrading the initial energy of the heavy ions. Precise depth dose distributions were measured by a small parallel plate ionization chamber and a variable length water column. LET (linear energy transfer) of the heavy ion radiation fields were measured by a parallel plate proportional chamber. From these basic measurements, biological experiments using these heavy ions are now carried out at this facility. (author)

  1. An examination of human factors in external beam radiation therapy: Findings and implications

    International Nuclear Information System (INIS)

    To better understand the contributing factors to human error in external beam radiation therapy, the US Nuclear Regulatory Commission has undertaken a series of human factors evaluations. A team of human factors specialists, assisted by a panel of radiation oncologists, medical physicists, and radiation technologists, conducted visits to 24 radiation oncology departments at community hospitals, university centers, and free-standing clinics. A function and task analysis was initially performed to guide subsequent evaluations in the areas of human-system interfaces, procedures, training and qualifications, and organizational policies and practices. Representative findings and implications for improvement are discussed within the context of a dynamic model which holds that misadministration likely results from the unanticipated interaction of several necessary but singly insufficient conditions

  2. CMS Run-2 Instrumentation for beam radiation and luminosity measurement using novel detector technologies

    Science.gov (United States)

    Gomez Espinosa, Alejandro; CMS Collaboration Collaboration

    2016-03-01

    The higher energy and luminosity for Run 2 at the LHC initiated the development of dedicated technologies for beam radiation monitoring and luminosity measurement. A dedicated pixel luminosity detector measures coincidences in several three layer telescopes of silicon pixel detectors to arrive at a luminosity for each colliding LHC bunch pair. The full pixel data is also read out at a lower rate to reconstruct charged particle tracks for monitoring and beam spot determination. The upgraded fast beam conditions monitor measures the particle flux using 24 two pad single crystalline diamond sensors, equipped with a fast front-end ASIC, produced in 130 nm CMOS technology, for excellent time resolution. A new beam-halo monitor exploits Cerenkov light production in fused quartz crystals to provide direction sensitivity and excellent time resolution to separate incoming and outgoing particles. The back-end electronics of the beam monitoring systems include dedicated modules with high bandwidth digitizers developed in both VME and microTCA standards for per bunch beam measurements and gain monitoring. All sub-detectors have been taking data from the first day of LHC operation in April 2015. Detector performance results from the 2015 LHC Run II will be presented.

  3. Synchrotron radiation and beam tube vacuum in a Very Large Hadron Collider, Stage 1 and Stage 2 VLHC

    International Nuclear Information System (INIS)

    Synchrotron radiation induced photodesorption in particle accelerators may lead to pressure rise and to beam-gas scattering losses, finally affecting the beam lifetime [1]. We discuss the beam tube vacuum in the low field Stage 1 and Stage 2 Very Large Hadron Collider VLHC. Since VLHC Stage 1 has a room temperature beam tube, a non-evaporable getter (NEG St101 strip) pumping system located inside a pumping antechamber, supplemented by lumped ion pumps for pumping methane is considered. In Stage 2, the ∼100 K beam screen, or liner, illuminated by the synchrotron radiation, is inserted into the magnet cold bore. Cryo-pumping is provided by the cold bore kept at 4.2 K, through slots covering the beam screen surface. Possible beam conditioning scenarios are presented for reaching design intensity, both for Stage 1 and 2. The most important results are summarized in this paper

  4. A Novel Approach to Beam Steering Using Arrays Composed of Multiple Unique Radiating Modes

    Science.gov (United States)

    Labadie, Nathan Richard

    Phased array antennas have found wide application in both radar and wireless communications systems particularly as implementation costs continue to decrease. The primary advantages of electronically scanned arrays are speed of beam scan and versatility of beamforming compared to mechanically scanned fixed beam antennas. These benefits come at the cost of a few well known design issues including element pattern rolloff and mutual coupling between elements. Our primary contribution to the field of research is the demonstration of significant improvement in phased array scan performance using multiple unique radiating modes. In short, orthogonal radiating modes have minimal coupling by definition and can also be generated with reduced rolloff at wide scan angles. In this dissertation, we present a combination of analysis, full-wave electromagnetic simulation and measured data to support our claims. The novel folded ring resonator (FRR) antenna is introduced as a wideband and multi-band element embedded in a grounded dielectric substrate. Multiple radiating modes of a small ground plane excited by a four element FRR array were also investigated. A novel hemispherical null steering antenna composed of two collocated radiating elements, each supporting a unique radiating mode, is presented in the context of an anti-jam GPS receiver application. Both the antenna aperture and active feed network were fabricated and measured showing excellent agreement with analytical and simulated data. The concept of using an antenna supporting multiple radiating modes for beam steering is also explored. A 16 element hybrid linear phased array was fabricated and measured demonstrating significantly improved scan range and scanned gain compared to a conventional phased array. This idea is expanded to 2 dimensional scanning arrays by analysis and simulation of a hybrid phased array composed of novel multiple mode monopole on patch antenna sub-arrays. Finally, we fabricated and

  5. External-beam radiation therapy after surgical resection and intraoperative electron-beam radiation therapy for oligorecurrent gynecological cancer. Long-term outcome

    Energy Technology Data Exchange (ETDEWEB)

    Sole, C.V. [Hospital General Universitario Gregorio Maranon, Department of Oncology, Madrid (Spain); Complutense University, School of Medicine, Madrid (Spain); Instituto de Radiomedicina, Service of Radiation Oncology, Santiago (Chile); Hospital General Universitario Gregorio Maranon, Institute of Research Investigation, Madrid (Spain); Calvo, F.A. [Hospital General Universitario Gregorio Maranon, Department of Oncology, Madrid (Spain); Complutense University, School of Medicine, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Institute of Research Investigation, Madrid (Spain); Lozano, M.A.; Gonzalez-Sansegundo, C. [Hospital General Universitario Gregorio Maranon, Department of Oncology, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Service of Radiation Oncology, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Institute of Research Investigation, Madrid (Spain); Gonzalez-Bayon, L. [Hospital General Universitario Gregorio Maranon, Service of General Surgery, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Institute of Research Investigation, Madrid (Spain); Alvarez, A. [Hospital General Universitario Gregorio Maranon, Service of Radiation Oncology, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Institute of Research Investigation, Madrid (Spain); Lizarraga, S. [Hospital General Universitario Gregorio Maranon, Department of Gynecology, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Institute of Research Investigation, Madrid (Spain); Garcia-Sabrido, J.L. [Complutense University, School of Medicine, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Service of General Surgery, Madrid (Spain); Hospital General Universitario Gregorio Maranon, Department of Gynecology, Madrid (Spain)

    2014-02-15

    The goal of the present study was to analyze prognostic factors in patients treated with external-beam radiation therapy (EBRT), surgical resection and intraoperative electron-beam radiotherapy (IOERT) for oligorecurrent gynecological cancer (ORGC). From January 1995 to December 2012, 61 patients with ORGC [uterine cervix (52 %), endometrial (30 %), ovarian (15 %), vagina (3 %)] underwent IOERT (12.5 Gy, range 10-15 Gy), and surgical resection to the pelvic (57 %) and paraaortic (43 %) recurrence tumor bed. In addition, 29 patients (48 %) also received EBRT (range 30.6-50.4 Gy). Survival outcomes were estimated using the Kaplan-Meier method, and risk factors were identified by univariate and multivariate analyses. Median follow-up time for the entire cohort of patients was 42 months (range 2-169 months). The 10-year rates for overall survival (OS) and locoregional control (LRC) were 17 and 65 %, respectively. On multivariate analysis, no tumor fragmentation (HR 0.22; p = 0.03), time interval from primary tumor diagnosis to locoregional recurrence (LRR) < 24 months (HR 4.02; p = 0.02) and no EBRT at the time of pelvic recurrence (HR 3.95; p = 0.02) retained significance with regard to LRR. Time interval from primary tumor to LRR < 24 months (HR 2.32; p = 0.02) and no EBRT at the time of pelvic recurrence (HR 3.77; p = 0.04) showed a significant association with OS after adjustment for other covariates. External-beam radiation therapy at the time of pelvic recurrence, time interval for relapse ≥24 months and not multi-involved fragmented resection specimens are associated with improved LRC in patients with ORGC. As suggested from the present analysis a significant group of ORGC patients could potentially benefit from multimodality rescue treatment. (orig.)

  6. External-beam radiation therapy after surgical resection and intraoperative electron-beam radiation therapy for oligorecurrent gynecological cancer. Long-term outcome

    International Nuclear Information System (INIS)

    The goal of the present study was to analyze prognostic factors in patients treated with external-beam radiation therapy (EBRT), surgical resection and intraoperative electron-beam radiotherapy (IOERT) for oligorecurrent gynecological cancer (ORGC). From January 1995 to December 2012, 61 patients with ORGC [uterine cervix (52 %), endometrial (30 %), ovarian (15 %), vagina (3 %)] underwent IOERT (12.5 Gy, range 10-15 Gy), and surgical resection to the pelvic (57 %) and paraaortic (43 %) recurrence tumor bed. In addition, 29 patients (48 %) also received EBRT (range 30.6-50.4 Gy). Survival outcomes were estimated using the Kaplan-Meier method, and risk factors were identified by univariate and multivariate analyses. Median follow-up time for the entire cohort of patients was 42 months (range 2-169 months). The 10-year rates for overall survival (OS) and locoregional control (LRC) were 17 and 65 %, respectively. On multivariate analysis, no tumor fragmentation (HR 0.22; p = 0.03), time interval from primary tumor diagnosis to locoregional recurrence (LRR) < 24 months (HR 4.02; p = 0.02) and no EBRT at the time of pelvic recurrence (HR 3.95; p = 0.02) retained significance with regard to LRR. Time interval from primary tumor to LRR < 24 months (HR 2.32; p = 0.02) and no EBRT at the time of pelvic recurrence (HR 3.77; p = 0.04) showed a significant association with OS after adjustment for other covariates. External-beam radiation therapy at the time of pelvic recurrence, time interval for relapse ≥24 months and not multi-involved fragmented resection specimens are associated with improved LRC in patients with ORGC. As suggested from the present analysis a significant group of ORGC patients could potentially benefit from multimodality rescue treatment. (orig.)

  7. Radiation Therapy of Large Intact Breasts Using a Beam Spoiler or Photons with Mixed Energies

    International Nuclear Information System (INIS)

    Radiation treatment of large intact breasts with separations of more than 24 cm is typically performed using x-rays with energies of 10 MV and higher, to eliminate high-dose regions in tissue. The disadvantage of the higher energy beams is the reduced dose to superficial tissue in the buildup region. We evaluated 2 methods of avoiding this underdosage: (1) a beam spoiler: 1.7-cm-thick Lucite plate positioned in the blocking tray 35 cm from the isocenter, with 15-MV x-rays; and (2) combining 6- and 15-MV x-rays through the same portal. For the beam with the spoiler, we measured the dose distribution for normal and oblique incidence using a film and ion chamber in polystyrene, as well as a scanning diode in a water tank. In the mixed-energy approach, we calculated the dose distributions in the buildup region for different proportions of 6- and 15-MV beams. The dose enhancement due to the beam spoiler exhibited significant dependence upon the source-to-skin distance (SSD), field size, and the angle of incidence. In the center of a 20 x 20-cm2 field at 90-cm SSD, the beam spoiler raises the dose at 5-mm depth from 77% to 87% of the prescription, while maintaining the skin dose below 57%. Comparison of calculated dose with measurements suggested a practical way of treatment planning with the spoiler-usage of 2-mm 'beam' bolus-a special option offered by in-house treatment planning system. A second method of increasing buildup doses is to mix 6- and 15-MV beams. For example, in the case of a parallel-opposed irradiation of a 27-cm-thick phantom, dose to Dmax for each energy, with respect to midplane, is 114% for pure 6-, 107% for 15-MV beam with the spoiler, and 108% for a 3:1 mixture of 15- and 6-MV beams. Both methods are practical for radiation therapy of large intact breasts

  8. Control of Coherent Synchrotron Radiation and Micro-Bunching Effects During Transport of High Brightness Electron Beams

    CERN Document Server

    Douglas, D R; Hutton, A; Krafft, G A; Li, R; Neil, G R; Roblin, Y; Tennant, C D; Tsai, C -Y

    2014-01-01

    Beam quality preservation during transport of high-brightness electron beams is of general concern in the design of modern accelerators. Methods to manage incoherent synchrotron radiation (ISR) have been in place for decades; as beam brightness has improved coherent synchrotron radiation (CSR) and the microbunching instability (uBI) have emerged as performance limitations. We apply the compensation analysis of diMitri, Cornacchia, and Spampinati - as previously used by Borland - to the design of transport systems for use with low-emittance beams, and find that appropriately configured second order achromats will suppress transverse emittance growth due to CSR and appear to limit uBI gain.

  9. Beam-induced radiation in the compact muon solenoid tracker at the Large Hadron Collider

    Indian Academy of Sciences (India)

    A P Singh; P C Bhat; N V Mokhov; S Beri

    2010-05-01

    The intense radiation environment at the Large Hadron Collider, CERN at a design energy of $\\sqrt{s} = 14$ TeV and a luminosity of 1034 cm−2S−1 poses unprecedented challenges for safe operation and performance quality of the silicon tracker detectors in the CMS and ATLAS experiments. The silicon trackers are crucial for the physics at the LHC experiments, and the inner layers, being situated only a few centimeters from the interaction point, are most vulnerable to beam-induced radiation. We have recently carried out extensive Monte Carlo simulation studies using MARS program to estimate particle fluxes and radiation dose in the CMS silicon pixel and strip trackers from proton–proton collisions at $\\sqrt{s} = 14$ TeV and from machine-induced background such as beam–gas interactions and beam halo. We will present results on radiation dose, particle fluxes and spectra from these studies and discuss implications for radiation damage and performance of the CMS silicon tracker detectors.

  10. Palliative treatment of advanced cancer using multiple nonconfluent pencil beam radiation. A pilot study

    International Nuclear Information System (INIS)

    In the era of orthovoltage radiation, multiple nonconfluent pencil beam radiation (GRID) therapy was utilized to minimize superficial normal tissue damage while delivering tumorcidal doses at specified depths in tissues. The success of GRID therapy was based on the fact that small volumes of tissues could tolerate high doses of radiation. Since the development of megavoltage radiation and skin sparing, GRID therapy has been abandoned. In a pilot study, the authors adapted the principles of GRID therapy to megavoltage photon beams to treat patients with massive tumors or recurrent tumors after tolerance doses of radiation. Twenty-two patients have been entered in the study. All patients were symptomatic and had exhaustive conventional surgery, chemotherapy, and radiotherapy approaches to treatment. A 50:50 GRID (open to closed areas) was utilized, and a prescribed dose of 1000 to 1500 cGy to the open areas was given using a single photon field. In four patients, a second GRID treated was delivered at a split course interval of 4 weeks. The follow-up in these patients ranges from 1 month to 18 months. The results of treatment have been remarkable with 20 of 22 patients achieving dramatic relief of severe symptoms, and several patients showing significant objective regression. No acute effects have been observed, including those patients having large volumes of the abdomen irradiated. No unusual skin or subcutaneous early or late damage has been observed in follow-up

  11. Protective effect of allium sativum ethanol extract on cultured human lymphocytes against electron beam radiation

    International Nuclear Information System (INIS)

    The development of radioprotective agent has been the subject of intense research because exposure to ionizing radiation causes DNA damage which may cause mutation and ultimately leads to cancer, on the other hand radiotherapy has become an integral part in treatment of cancer which uses ionizing radiations like X rays, gamma rays to kill the cancer cells. Amifostine is a well-known radioprotector which is clinically approved. There are many other radioprotectors like cysteine, cystamine, serotine but they are not used because of its normal tissue toxicity. Allium sativum is commonly known as garlic which has already been reported for its medicinal properties. In this study we evaluated radioprotection property of Allium sativum on DNA damage caused by electron beam radiation in cultured human lymphocytes. Allium sativum ethanol extract was used for this study. Cell viability was performed by MTT assay. DNA damage was assessed by comet assay parameters. The cultured lymphocytes were incubated with different concentrations 10, 50 and 100 μg/mL of Allium sativum extracts for 2, 4, 6 and 24 hour time intervals. Treatment of lymphocytes with various concentration of Allium sativum extract resulted in significant decrease in the level of DNA damage (Percentage tail DNA 6%) and increase in cell viability 93% (p>0.05) compare to the radiation control group. Results of this study revealed that Allium sativum protects cultured lymphocytes when exposed to electron beam radiation at its sub lethal dose. (author)

  12. Ion-beam simulation of radiation damage produced by fast neutrons in heterophase structures

    Energy Technology Data Exchange (ETDEWEB)

    Tetelbaum, D.I., E-mail: tetelbaum@phys.unn.ru [Lobachevsky State University of Nizhny Novgorod, 23/3 Gagarin prospect, Nizhny Novgorod, 603950 (Russian Federation); Guseinov, D.V.; Vasiliev, V.K.; Mikhaylov, A.N.; Belov, A.I.; Korolev, D.S.; Obolensky, S.V. [Lobachevsky State University of Nizhny Novgorod, 23/3 Gagarin prospect, Nizhny Novgorod, 603950 (Russian Federation); Kachemtsev, A.N. [Sedakov Scientific-Research Institute, GSP-486, Nizhny Novgorod 603950 (Russian Federation)

    2014-05-01

    3D Monte-Carlo algorithm and computer code have been developed that allows choosing and optimizing the conditions of ion irradiation needed for the adequate ion-beam simulation of radiation damage under fast neutron irradiation. It is established that, by the proper selection of energy and dose of Si{sup +} ions, it is possible to reproduce well the effect of irradiation with fission neutrons of subsurface and buried layers of silicon or Si-based 2D and 3D-heterostructures. The results can be used for testing the radiation hardness of silicon-based electronic and optoelectronic device structures.

  13. Modelling radiation fields of ion beams in tissue-like materials

    International Nuclear Information System (INIS)

    Fast nuclei are ionizing radiation which can cause deleterious effects to irradiated cells. The modelling of the interactions of such ions with matter and the related effects are very important to physics, radiobiology, medicine and space science and technology. A powerful method to study the interactions of ionizing radiation with biological systems was developed in the field of microdosimetry. Microdosimetry spectra characterize the energy deposition to objects of cellular size, i.e., a few micrometers. In the present thesis the interaction of ions with tissue-like media was investigated using the Monte Carlo model for Heavy-Ion Therapy (MCHIT) developed at the Frankfurt Institute for Advanced Studies. MCHIT is a Geant4-based application intended to benchmark the physical models of Geant4 and investigate the physical properties of therapeutic ion beams. We have implemented new features in MCHIT in order to calculate microdosimetric quantities characterizing the radiation fields of accelerated nucleons and nuclei. The results of our Monte Carlo simulations were compared with recent experimental microdosimetry data. In addition to microdosimetry calculations with MCHIT, we also investigated the biological properties of ion beams, e.g. their relative biological effectiveness (RBE), by means of the modified Microdosimetric-Kinetic model (MKM). The MKM uses microdosimetry spectra in describing cell response to radiation. MCHIT+MKM allowed us to study the physical and biological properties of ion beams. The main results of the thesis are as follows: MCHIT is able to describe the spatial distribution of the physical dose in tissue-like media and microdosimetry spectra for ions with energies relevant to space research and ion-beam cancer therapy; MCHIT+MKM predicts a reduction of the biological effectiveness of ions propagating in extended medium due to nuclear fragmentation reactions; We predicted favourable biological dose-depth profiles for monoenergetic helium and

  14. Small Radiation Beam Dosimetry for Radiosurgery of Trigeminal Neuralgia: One Case Analysis

    Science.gov (United States)

    García-Garduño, O. A.; Lárraga-Gutiérrez, J. M.; Rodríguez-Villafuerte, M.; Martínez-Dávalos, A.; Moreno-Jiménez, S.; Suárez-Campos, J. J.; Celis, M. A.

    2008-08-01

    The use of small radiation beams for trigeminal neuralgia (TN) treatment requires high precision and accuracy in dose distribution calculations and delivery. Special attention must be kept on the type of detector to be used. In this work, the use of GafChromic EBT® radiochromic and X-OMAT V2 radiographic films for small radiation beam characterization is reported. The dosimetric information provided by the films (total output factors, tissue maximum ratios and off axis ratios) is compared against measurements with a shielded solid state (diode) reference detector. The film dosimetry was used for dose distribution calculations for the treatment of trigeminal neuralgia radiosurgery. Comparison of the isodose curves shows that the dosimetry produced with the X-OMAT radiographic film overestimates the dose distributions in the penumbra region.

  15. Small Radiation Beam Dosimetry for Radiosurgery of Trigeminal Neuralgia: One Case Analysis

    International Nuclear Information System (INIS)

    The use of small radiation beams for trigeminal neuralgia (TN) treatment requires high precision and accuracy in dose distribution calculations and delivery. Special attention must be kept on the type of detector to be used. In this work, the use of GafChromic EBT registered radiochromic and X-OMAT V2 radiographic films for small radiation beam characterization is reported. The dosimetric information provided by the films (total output factors, tissue maximum ratios and off axis ratios) is compared against measurements with a shielded solid state (diode) reference detector. The film dosimetry was used for dose distribution calculations for the treatment of trigeminal neuralgia radiosurgery. Comparison of the isodose curves shows that the dosimetry produced with the X-OMAT radiographic film overestimates the dose distributions in the penumbra region

  16. In vivo pink-beam imaging and fast alignment procedure for rat brain tumor radiation therapy.

    Science.gov (United States)

    Nemoz, Christian; Kibleur, Astrid; Hyacinthe, Jean Noël; Berruyer, Gilles; Brochard, Thierry; Bräuer-Krisch, Elke; Le Duc, Géraldine; Brun, Emmanuel; Elleaume, Hélène; Serduc, Raphaël

    2016-01-01

    A fast positioning method for brain tumor microbeam irradiations for preclinical studies at third-generation X-ray sources is described. The three-dimensional alignment of the animals relative to the X-ray beam was based on the X-ray tomography multi-slices after iodine infusion. This method used pink-beam imaging produced by the ID17 wiggler. A graphical user interface has been developed in order to define the irradiation parameters: field width, height, number of angles and X-ray dose. This study is the first reporting an image guided method for soft tissue synchrotron radiotherapy. It allowed microbeam radiation therapy irradiation fields to be reduced by a factor of ∼20 compared with previous studies. It permitted more targeted, more efficient brain tumor microbeam treatments and reduces normal brain toxicity of the radiation treatment. PMID:26698083

  17. Coherent transition radiation-based diagnosis of electron beam pulse shape

    International Nuclear Information System (INIS)

    The bunch shapes of an electron beams is increasingly difficult to measure, as the time-scales of interest are now sub-picosecond. We discuss here the use of coherent transition radiation CTR for such measurements. Two types of measurements are presented: the deduction of macroscopic (0.3 psec resolution) pulse profile using interferometry, and the examination of microbunch (50 fsec) structure from an FEL-bunched beam using spectral characteristics of the CTR. For the macrobunch measurement we discuss the problem of missing low frequency radiation and one solution for extracting meaningful data with this problem present. For microbunch CTR, we examing initial spectrally resolved measurements, and some interesting deviations in the CTR spectrum from the standard theoretical predictions. copyright 1999 American Institute of Physics

  18. Synergy effect of radiation damage on 12Cr-ODS steel by multi-ion-beams

    International Nuclear Information System (INIS)

    In this work, 12Cr-ODS steel samples were irradiated by different combinations of Si, He and H ion beams at room temperature. Mechanical property measurements of the irradiated samples showed that all the samples exhibited irradiation swelling and hardening,but the sample co-irradiated by three ion beams had the biggest swelling and smallest hardening. Combining on the TEM imaging,analyses of irradiation changes of 12Cr-ODS steel samples were carried out. Raman spectra of the irradiated samples revealed carbon precipitated inside the samples, and carbon peak distribution could reflect the radiation damage distribution. The results, which accumulated experimental data and clarified the radiation damage to nuclear materials by synergy effect, are of help for application of 12Cr-ODS steel in an advanced reactor. (authors)

  19. Processing researches on radiation vulcanization of natural rubber latex with low energy electron beam machine

    International Nuclear Information System (INIS)

    Processing researches on radiation vulcanization of natural rubber latex (RVNRL) was carried out with low energy electron beam machine, and explored the impact of RVNRL in a variety of factors. The results showed: It was beneficial to manufacture with increasing the dry rubber content of latex and increasing beam current. It was important to increase strength of RVNRL film using natural latex with higher green strength. Added to 0.5-1.5 phr (parts per hundreds of rubber) of PVA (polyvinyl alcohol) in radiation vulcanized latex, then the centrifugal method can greatly remove the water-soluble proteins, so that the residual water-soluble proteins in films or products can be reduced to acceptable levels. (authors)

  20. Radiation exposure in a modern, circularly scanned-beam laminographic X-ray inspection system.

    Science.gov (United States)

    Fazzio, R S

    1998-01-01

    Circularly scanned-beam laminography is currently the predominant technique used for the nondestructive examination of printed circuit solder assemblies via cross-sectional X-ray imaging. Given industry trends towards double-sided assemblies and limited access components, cross-sectional X-ray inspection is furthermore becoming increasingly important. Use of X-rays for inspection of solder joints on loaded printed circuit boards nonetheless often leads to concern surrounding possible undesirable radiation effects on the circuitry mounted on the board. In this paper we develop a simple analytical model useful for predicting the radiation exposure rates in a scanned-beam laminography system. We demonstrate the validity of the model through a series of dosimetry experiments. PMID:22388470

  1. External beam radiation therapy and retinoblastoma: Long-term results in the comparison of two techniques

    International Nuclear Information System (INIS)

    Purpose: This study compares the long-term actuarial local control, eye conservation rate, survival, and ocular complications in children with retinoblastoma treated with two different external beam treatment techniques. Methods and Materials: From 1979-1991, 182 eyes in 123 children (104 bilateral) received primary external beam radiation therapy. An anterior lens-sparing electron beam technique delivering 38 to 50 Gy in 2.5 Gy fractions was used in 67 eyes from 1979-1984 and a modified lateral beam technique, delivering 42 to 46 Gy in 2 Gy fractions, was used in 113 eyes from 1984-1991. These groups were balanced with respect to known prognostic variables. Results: For Group I-III eyes, the 5- and 8-year local control was significantly improved using the modified lateral beam technique (84%) compared to (38%) using the anterior lens sparing technique (p p ≤ 0.0001). For Group IV-V eyes, the 5- and 8-year local control rates were not statistically different, despite a trend favoring the modified lateral beam technique. Survival endpoints including eye survival (no enucleation), cause-specific survival, and overall survival comparing the two treatment techniques were not significantly different. Overall, 22% of eyes developed cataracts. There was no difference between the two treatment groups in terms of cataract development. No eyes required enucleation for ocular complications. Conclusion: There is a significant improvement in local control using the modified lateral beam technique compared to an anterior lens-sparing approach for Group I-III eyes. However, there was no difference in survival end points between the two treatment techniques. The incidence of ocular complications using these two external beam techniques is acceptable.

  2. Radiation hygienization of cattle and swine slurry with high energy electron beam

    International Nuclear Information System (INIS)

    The research was carried out to assess the efficiency of radiation hygienization of cattle and swine slurry of different density using the high energy electron beam based on the inactivation rate of Salmonella ssp, Escherichia coli, Enterococcus spp and Ascaris suum eggs. The experiment was conducted with use of the linear electron accelerator Elektronika 10/10 in Institute of Nuclear Chemistry and Technology in Warsaw. The inoculated slurry samples underwent hygienization with high energy electron beam of 1, 3, 5, 7 and 10 kGy. Numbers of reisolated bacteria were determined according to the MPN method, using typical microbiological media. Theoretical lethal doses, D90 doses and hygienization efficiency of high energy electron beam were determined. The theoretical lethal doses for all tested bacteria ranged from 3.63 to 8.84 kGy and for A. suum eggs from 4.07 to 5.83 kGy. Salmonella rods turned out to be the most sensitive and Enterococcus spp were the most resistant to electron beam hygienization. The effectiveness or radiation hygienization was lower in cattle than in swine slurry and in thick than in thin one. Also the species or even the serotype of bacteria determined the dose needed to inactivation of microorganisms. - Highlights: ► The hygienic efficiency of electron beam against slurry was researched. ► The hygienization efficiency depended on the slurry characteristics and microorganism species. ► In most of the cases 7 kGy dose was sufficient for slurry hygienization. ► Dose below 1 kGy allowed for 90% elimination of microorganism population. ► The radiation hygienization is a good alternative for typical slurry treatment methods

  3. System for detecting neutrons in the harsh radiation environment of a relativistic electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Kruse, L.W.

    1978-06-01

    Newly developed detectors and procedures allow measurement of neutron yield and energy in the harsh radiation environment of a relativistic electron beam source. A new photomultiplier tube design and special gating methods provide the basis for novel time-of-flight and total-yield detectors. The technique of activation analysis is expanded to provide a neutron energy spectrometer. There is a demonstrated potential in the use of the integrated system as a valuable diagnostic tool to study particle-beam fusion, intense ion-beam interactions, and pulsed neutron sources for simulating weapons effects. A physical lower limit of 10/sup 8/ neutrons into 4..pi.. is established for accurate and meaningful measurements in the REB environment.

  4. System for detecting neutrons in the harsh radiation environment of a relativistic electron beam

    International Nuclear Information System (INIS)

    Newly developed detectors and procedures allow measurement of neutron yield and energy in the harsh radiation environment of a relativistic electron beam source. A new photomultiplier tube design and special gating methods provide the basis for novel time-of-flight and total-yield detectors. The technique of activation analysis is expanded to provide a neutron energy spectrometer. There is a demonstrated potential in the use of the integrated system as a valuable diagnostic tool to study particle-beam fusion, intense ion-beam interactions, and pulsed neutron sources for simulating weapons effects. A physical lower limit of 108 neutrons into 4π is established for accurate and meaningful measurements in the REB environment

  5. Cerenkov light spectrum in an optical fiber exposed to a photon or electron radiation therapy beam

    International Nuclear Information System (INIS)

    A Cerenkov signal is generated when energetic charged particles enter the core of an optical fiber. The Cerenkov intensity can be large enough to interfere with signals transmitted through the fiber. We determine the spectrum of the Cerenkov background signal generated in a poly(methyl methacrylate) optical fiber exposed to photon and electron therapeutic beams from a linear accelerator. This spectral measurement is relevant to discrimination of the signal from the background, as in scintillation dosimetry using optical fiber readouts. We find that the spectrum is approximated by the theoretical curve after correction for the wavelength dependent attenuation of the fiber. The spectrum does not depend significantly on the angle between the radiation beam and the axis of the fiber optic but is dependent on the depth in water at which the fiber is exposed to the beam.

  6. Instrumentation for beam radiation and luminosity measurement in the CMS experiment using novel detector technologies

    CERN Document Server

    Guthoff, Moritz

    2016-01-01

    The higher energy and luminosity of the LHC initiated the development of dedicated technologies for radiation monitoring and luminosity measurement. A pixelated luminosity detector counts coincidences in several three layer telescopes of silicon pixel detectors to measure the luminosity for each colliding LHC bunch pair. In addition, charged particle tracking allows to monitor the location of the collision point.The upgraded fast beam conditions monitor measures the particle flux using 24 two pad single crystalline diamond sensors, equipped with a fast front-end ASIC produced in 130 nm CMOS technology. The excellent time resolution is used to separate collision products from machine induced background.A new beam-halo monitor at larger radius exploits Cerenkov light produced by relativistic charged particles in fused quartz crystals to provide direction sensitivity and time resolution to separate incoming and outgoing particles. The back-end electronics of the beam monitoring systems includes dedicated modules...

  7. Intraoperative radiotherapy given as a boost for early breast cancer: Long-term clinical and cosmetic results

    International Nuclear Information System (INIS)

    Purpose: The standard radiotherapy (RT) of breast cancer consists of 50 Gy external beam RT (EBRT) to the whole breast followed by an electron boost of 10-16 Gy to the tumor bed, but this has several cosmetic disadvantages. Intraoperative radiotherapy (IORT) could be an alternative to overcome these. Methods and Materials: We evaluated 50 women with early breast cancer operated on in a dedicated IORT facility. Median dose of 10 Gy was delivered using 9-MeV electron beams. All patients received postoperative EBRT (50 Gy in 2 Gy fractions). Late toxicity and cosmetic results were assessed independently by two physicians according to the Common Terminology Criteria for Adverse Event v3.0 grading system and the European Organization for Research and Treatment of Cancer questionnaires. Results: After a median follow-up of 9.1 years (range, 5-15 years), two local recurrences were observed within the primary tumor bed. At the time of analysis, 45 patients are alive with (n = 1) or without disease. Among the 42 disease-free remaining patients, 6 experienced Grade 2 late subcutaneous fibrosis within the boost area. Overall, the scores indicated a very good quality of life and cosmesis was good to excellent in the evaluated patients. Conclusion: Our results confirm that IORT given as a boost after breast-conserving surgery is a reliable alternative to conventional postoperative fractionated boost radiation

  8. T2-weighted endorectal magnetic resonance imaging of prostate cancer after external beam radiation therapy

    Directory of Open Access Journals (Sweden)

    Antonio C. Westphalen

    2009-04-01

    Full Text Available PURPOSE: To retrospectively determine the accuracy of T2-weighted endorectal MR imaging in the detection of prostate cancer after external beam radiation therapy and to investigate the relationship between imaging accuracy and time since therapy. MATERIAL AND METHODS: Institutional review board approval was obtained and the study was HIPPA compliant. We identified 59 patients who underwent 1.5 Tesla endorectal MR imaging of the prostate between 1999 and 2006 after definitive external beam radiation therapy for biopsy-proven prostate cancer. Two readers recorded the presence or absence of tumor on T2-weighted images. Logistic regression and Fisher’s exact tests for 2x2 tables were used to determine the accuracy of imaging and investigate if accuracy differed between those imaged within 3 years of therapy (n = 25 and those imaged more than 3 years after therapy (n = 34. Transrectal biopsy was used as the standard of reference for the presence or absence of recurrent cancer. RESULTS: Thirty-four of 59 patients (58% had recurrent prostate cancer detected on biopsy. The overall accuracy of T2-weighted MR imaging in the detection cancer after external beam radiation therapy was 63% (37/59 for reader 1 and 71% for reader 2 (42/59. For both readers, logistic regression showed no difference in accuracy between those imaged within 3 years of therapy and those imaged more than 3 years after therapy (p = 0.86 for reader 1 and 0.44 for reader 2. CONCLUSION: T2-weighted endorectal MR imaging has low accuracy in the detection of prostate cancer after external beam radiation therapy, irrespective of the time since therapy.

  9. Radiation effects in LiB3O5 nonlinear crystals under eletron beam irradiation

    International Nuclear Information System (INIS)

    Investigation results on defect accumulation in LiB3O5 crystals under electron beam irradiation are presented. A conclusion has been made about the role of radiation-induced defects in the accumulation of electric charges in LBO crystals under destructive electron irradiation due to electric breakdown. The processes considered can simulate defect formation in a crystaltransformer based on LBO affected by powerful laser pulses

  10. Exercise for laboratory comparison of calibration coefficient in 137Cs beam, radiation protection - 2013/2014

    International Nuclear Information System (INIS)

    This work deals with the preliminary results of the second exercise of comparing the radiation monitors calibration laboratories in Brazil. The exercise involved eight laboratories and the measured quantity is the air kerma in a beam of 137Cs for radioprotection. The exercise was conducted by the LNMRI/IRD, in a star shaped arrangement from October 2013 to July 2015. The largest deviation was 2% of the calibration coefficient that is acceptable for applications in radioprotection. (author)

  11. A novel method for sub-micrometer transverse electron beam size measurements using optical transition radiation

    OpenAIRE

    Aryshev, A.; Boogert, S. T.; Howell, D.; Karataev, P.; Terunuma, N.; Urakawa, J.

    2010-01-01

    Optical Transition Radiation (OTR) appearing when a charged particle crosses a boundary between two media with different dielectric properties has widely been used as a tool for transverse profile measurements of charged particle beams in various facilities worldwide. The resolution of the monitor is defined by so-called Point Spread Function (PSF), source distribution generated by a single electron and projected by an optical system onto a screen. In this paper we represent the development o...

  12. Beam plug replacement and alignment under high radiation conditions for cold neutron facilities at Hanaro

    International Nuclear Information System (INIS)

    Full text : The HANARO, an open-tank-in-pool type research reactor of a 30 MWth power in Korea, has been operating for 15 years since its initial criticality in February 1995. The beam port assigned for the cold neutron at HANARO had been used for an 8-m SANS without neutron guides until it was replaced by a cold neutron guide system in 2008. It was developed a cold neutron guide system for the delivery of cold neutrons from the cold neutron source in the reactor to the neutron scattering instruments in the guide hall. Since the HANARO has been operated from 1995, it was a big challenge to replace the existing plug and shutter with the new facilities under high radiation conditions. When the old plug was removed from the beam port in 2008, the radiation level was 230 mSv/hr at the end of beam port. In addition to that, there were more difficult situations such as the poor as-built dimensions of the beam port, limited work space and time constraint due to other constructions in parallel in the reactor hall. Before the removal of the old plug the level of the radiation was measured coming out through a small hole of the plug to estimate the radiation level during the removal of the old plug and installation of a new plug. Based on the measurement and analysis results, special tools and various shielding facilities were developed for the removal of old in-pile plug and the installation of the new in-pile plug assembly safely. In 2008, the old plug and shutter were successfully replaced by the new plug and shutter as shown in this article with a minimum exposure to the workers. A laser tracker system was also one of the main factors in our successful installation and alignment under high radiation conditions and limited work space. The laser tracker was used to measure and align all the mechanical facilities and the neutron guides with a minimum radiation exposure to workers. The alignment of all the guides and accessories were possible during reactor operation because

  13. Laser-Driven Very High Energy Electron/Photon Beam Radiation Therapy in Conjunction with a Robotic System

    Directory of Open Access Journals (Sweden)

    Kazuhisa Nakajima

    2014-12-01

    Full Text Available We present a new external-beam radiation therapy system using very-high-energy (VHE electron/photon beams generated by a centimeter-scale laser plasma accelerator built in a robotic system. Most types of external-beam radiation therapy are delivered using a machine called a medical linear accelerator driven by radio frequency (RF power amplifiers, producing electron beams with an energy range of 6–20 MeV, in conjunction with modern radiation therapy technologies for effective shaping of three-dimensional dose distributions and spatially accurate dose delivery with imaging verification. However, the limited penetration depth and low quality of the transverse penumbra at such electron beams delivered from the present RF linear accelerators prevent the implementation of advanced modalities in current cancer treatments. These drawbacks can be overcome if the electron energy is increased to above 50 MeV. To overcome the disadvantages of the present RF-based medical accelerators, harnessing recent advancement of laser-driven plasma accelerators capable of producing 1-GeV electron beams in a 1-cm gas cell, we propose a new embodiment of the external-beam radiation therapy robotic system delivering very high-energy electron/photon beams with an energy of 50–250 MeV; it is more compact, less expensive, and has a simpler operation and higher performance in comparison with the current radiation therapy system.

  14. Radiation therapy for retinoblastoma: comparison of results with lens-sparing versus lateral beam techniques

    International Nuclear Information System (INIS)

    From 1979 through 1986, 170 children were seen at our institution diagnosed with retinoblastoma. Sixty-six of the children with involvement of 121 eyes, were referred for definitive external beam radiation to one or both eyes. During the study period, two distinct radiation techniques were used. From 1980 through mid-1984, a lens-sparing technique included an anterior electron beam with a contact lens mounted lead shield, combined with a lateral field, was used. Since mid-1984, a modified lateral beam technique has been used, mixing lateral electrons and superior and inferior lateral oblique split beam wedged photons. Doses prescribed were similar for both techniques, ranging from 3,850 to 5,000 cGy in 4 to 5 weeks. The lens-sparing and the modified lateral techniques are compared for local control. For eyes with Group I through III disease, the lens-sparing technique resulted in local control in 33% of the eyes treated, where the modified lateral technique controlled 83% of the eyes treated (p = .006). Mean time to relapse was identical in both groups, that is 24 and 26 months respectively. Most relapses were successfully treated with further local therapy, including laser or cryosurgery, or 60Co plaques. Five eyes required enucleation following initial treatment with the lens-sparing technique, but none thus far with the lateral beam technique. For eyes with Group IV and V disease, no significant differences were found between the two techniques in terms of local control or eventual need for enucleation. With a mean follow-up time of 33 months for the entire group, the 4-year survival is 93%. Two of the 4 deaths are due to second primary tumor, and all 4 have occurred in the lens-sparing group. Because follow-up time is more limited in the lateral beam group, this is not statistically significant and direct survival comparisons are premature

  15. Single-arm phase II study of conformal radiation therapy and temozolomide plus fractionated stereotactic conformal boost in high-grade gliomas. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Balducci, Mario; Manfrida, Stefania; Mangiola, Annunziato; Fiorentino, Alba; D' Agostino, Giuseppe Roberto; Frascino, Vincenzo; Dinapoli, Nicola; Mantini, Giovanna; Albanese, Alessio; De Bonis, Pasquale; Chiesa, Silvia; Valentini, Vincenzo; Anile, Carmelo; Cellini, Numa [Dept. of Radiotherapy, Catholic Univ. of the Sacred Heart, Rome (Italy); Apicella, Giuseppina [Dept. of Radiotherapy, Catholic Univ. of the Sacred Heart, Rome (Italy); Dept. of Radiotherapy, Univ. Hospital Maggiore della Carita, Novara (Italy); Azario, Luigi [Dept. of Physics, Catholic Univ. of the Sacred Heart, Rome (Italy)

    2010-10-15

    Purpose: To assess survival, local control and toxicity using fractionated stereotactic conformal radiotherapy (FSCRT) boost and temozolomide in high-grade gliomas (HGGs). Patients and Methods: Patients affected by HGG, with a CTV{sub 1} (clinical target volume, representing tumor bed {+-} residual tumor + a margin of 5 mm) {<=} 8 cm were enrolled into this phase II study. Radiotherapy (RT, total dose 6,940 cGy) was administered using a combination of two different techniques: three-dimensional conformal radiotherapy (3D-CRT, to achieve a dose of 5,040 or 5,940 cGy) and FSCRT boost (19 or 10 Gy) tailored by CTV{sub 1} diameter ({<=} 6 cm and > 6 cm, respectively). Temozolomide (75 mg/m{sup 2}) was administered during the first 2 or 4 weeks of RT, After the end of RT, temozolomide (150-200 mg/m{sup 2}) was administered for at least six cycles. The sample size of 41 patients was assessed by the single proportion-powered analysis. Results: 41 patients (36 with glioblastoma multiforme [GBM] and five with anaplastic astrocytoma [AA]) were enrolled; RTOG neurological toxicities G1-2 and G3 were 12% and 3%, respectively. Two cases of radionecrosis were observed. At a median follow-up of 44 months (range 6-56 months), global and GBM median overall survival (05) were 30 and 28 months. The 2-year survival rate was significantly better compared to the standard treatment (63% vs. 26.5%; p < 0.00001). Median progression-free survival (PFS) was 11 months, in GBM patients 10 months. Conclusion: FSCRT boost plus temozolomide is well tolerated and seems to increase survival compared to the standard treatment in patients with HGG. (orig.)

  16. When and how should we teach the basic concepts of radiation beam dosage

    International Nuclear Information System (INIS)

    The difficulty that many trainees, including those medically qualified, have in achieving a sound working grasp of certain basic principles of radiation beam dosage is often underestimated. Since any failure of understanding may seriously impair the efficiency of the team treating the patient, the discussion of these problems (and especially the monitoring of the results of such discussion by means of oral and written tests) deserves a high priority. Contrary to traditional practice, there would seem to be no good reason why teaching of radiation beam dosage, and the effect on dose-rate of changes in the treatment distance or in the amount of scattered radiation, should not begin in the very first week of training and be immediately integrated with discussion of the dose-rate information available at every radiotherapy unit when the patient is treated. A preliminary course of physics lectures does not usually make the understanding of these principles any easier and can be done either concurrently or later. For many radiotherapy trainees and for many doctors in other fields, comparison with drug dosage and with the brightness and scatter of ordinary light beams, avoiding technical terms so far as possible, may achieve a better initial understanding of basic principles than is achieved by mathematical equations and theoretical physics. (author)

  17. Treatment of Head and Neck Paragangliomas With External Beam Radiation Therapy

    International Nuclear Information System (INIS)

    Purpose: To retrospectively assess the outcomes of radiation therapy in patients with head and neck paragangliomas. Methods and Materials: From 1990 to 2009, 66 patients with 81 head and neck paragangliomas were treated by conventional external beam radiation therapy in 25 fractions at a median dose of 45 Gy (range, 41.4-68 Gy). One case was malignant. The median gross target volume and planning target volume were 30 cm3 (range, 0.9-243 cm3) and 116 cm3 (range, 24-731 cm3), respectively. Median age was 57.4 years (range, 15-84 years). Eleven patients had multicentric lesions, and 8 had family histories of paraganglioma. Paragangliomas were located in the temporal bone, the carotid body, and the glomus vagal in 51, 18, and 10 patients, respectively. Forty-six patients had exclusive radiation therapy, and 20 had salvage radiation therapy. The median follow-up was 4.1 years (range, 0.1-21.2 years). Results: One patient had a recurrence of temporal bone paraganglioma 8 years after treatment. The actuarial local control rates were 100% at 5 years and 98.7% at 10 years. Patients with multifocal tumors and family histories were significantly younger (42 years vs 58 years [P=.002] and 37 years vs 58 years [P=.0003], respectively). The association between family predisposition and multifocality was significant (P<.001). Two patients had cause-specific death within the 6 months after irradiation. During radiation therapy, 9 patients required hospitalization for weight loss, nausea, mucositis, or ophthalmic zoster. Two late vascular complications occurred (middle cerebral artery and carotid stenosis), and 2 late radiation-related meningiomas appeared 15 and 18 years after treatment. Conclusion: Conventional external beam radiation therapy is an effective and safe treatment option that achieves excellent local control; it should be considered as a first-line treatment of choice for head and neck paragangliomas

  18. Treatment of Head and Neck Paragangliomas With External Beam Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Dupin, Charles, E-mail: c.dupin@bordeaux.unicancer.fr [Department of Radiotherapy, Comprehensive Cancer Center, Institut Bergonié, Bordeaux (France); Lang, Philippe [Department of Radiotherapy, Pitié Salpétrière, Paris (France); Dessard-Diana, Bernadette [Department of Radiotherapy, Hopital Européen Georges Pompidou, Paris (France); Simon, Jean-Marc; Cuenca, Xavier; Mazeron, Jean-Jacques; Feuvret, Loïc [Department of Radiotherapy, Pitié Salpétrière, Paris (France)

    2014-06-01

    Purpose: To retrospectively assess the outcomes of radiation therapy in patients with head and neck paragangliomas. Methods and Materials: From 1990 to 2009, 66 patients with 81 head and neck paragangliomas were treated by conventional external beam radiation therapy in 25 fractions at a median dose of 45 Gy (range, 41.4-68 Gy). One case was malignant. The median gross target volume and planning target volume were 30 cm{sup 3} (range, 0.9-243 cm{sup 3}) and 116 cm{sup 3} (range, 24-731 cm{sup 3}), respectively. Median age was 57.4 years (range, 15-84 years). Eleven patients had multicentric lesions, and 8 had family histories of paraganglioma. Paragangliomas were located in the temporal bone, the carotid body, and the glomus vagal in 51, 18, and 10 patients, respectively. Forty-six patients had exclusive radiation therapy, and 20 had salvage radiation therapy. The median follow-up was 4.1 years (range, 0.1-21.2 years). Results: One patient had a recurrence of temporal bone paraganglioma 8 years after treatment. The actuarial local control rates were 100% at 5 years and 98.7% at 10 years. Patients with multifocal tumors and family histories were significantly younger (42 years vs 58 years [P=.002] and 37 years vs 58 years [P=.0003], respectively). The association between family predisposition and multifocality was significant (P<.001). Two patients had cause-specific death within the 6 months after irradiation. During radiation therapy, 9 patients required hospitalization for weight loss, nausea, mucositis, or ophthalmic zoster. Two late vascular complications occurred (middle cerebral artery and carotid stenosis), and 2 late radiation-related meningiomas appeared 15 and 18 years after treatment. Conclusion: Conventional external beam radiation therapy is an effective and safe treatment option that achieves excellent local control; it should be considered as a first-line treatment of choice for head and neck paragangliomas.

  19. Development and optimization of the LHC and the SPS beam diagnostics based on synchrotron radiation monitoring

    International Nuclear Information System (INIS)

    Measuring the beam transverse emittance is fundamental in every accelerator, in particular for colliders, where its precise determination is essential to maximize the luminosity and thus the performance of the colliding beams. Synchrotron Radiation (SR) is a versatile tool for non-destructive beam diagnostics, since its characteristics are closely related to those of the source beam. At CERN, being the only available diagnostics at high beam intensity and energy, SR monitors are exploited as the proton beam size monitor of the two higher energy machines, the Super Proton Synchrotron (SPS) and the Large Hadron Collider (LHC). The thesis work documented in this report focused on the design, development, characterization and optimization of these beam size monitors. Such studies were based on a comprehensive set of theoretical calculations, numerical simulations and experiments. A powerful simulation tool has been developed combining conventional softwares for SR simulation and optics design, thus allowing the description of an SR monitor from its source up to the detector. The simulations were confirmed by direct observations, and a detailed performance studies of the operational SR imaging monitor in the LHC, where different techniques for experimentally validating the system were applied, such as cross-calibrations with the wire scanners at low intensity (that are considered as a reference) and direct comparison with beam sizes de-convoluted from the LHC luminosity measurements. In 2015, the beam sizes to be measured with the further increase of the LHC beam energy to 7 TeV will decrease down to ∼190 μm. In these conditions, the SR imaging technique was found at its limits of applicability since the error on the beam size determination is proportional to the ratio of the system resolution and the measured beam size. Therefore, various solutions were probed to improve the system's performance such as the choice of one light polarization, the reduction of

  20. High-brightness electron beams for production of high intensity, coherent radiation for scientific and industrial applications

    International Nuclear Information System (INIS)

    Relativistic electron beams with high six-dimensional phase space densities, i.e., high-brightness beams, are the basis for efficient generation of intense and coherent radiation beams for advanced scientific and industrial applications. The remarkable progress in synchrotrons radiation facilities from the first generation to the current, third-generation capability illustrates this point. With the recent development of the high-brightness electron gun based on laser-driven rf photocathodes, linacs have become another important option for high-brightness electron beams. With linacs of about 100 MeV, megawatt-class infrared free-electron lasers can be designed for industrial applications such as power beaming. With linacs of about 10 GeV, 1- angstrom x-ray beams with brightness and time resolution exceeding by several orders of magnitude the current synchrotrons radiation sources can be generated based on self-amplified spontaneous emission. Scattering of a high-brightness electron beam by high power laser beams is emerging as a compact method of generating short-pulse, bright x-rays. In the high-energy frontier, photons of TeV quantum energy could be generated by scattering laser beams with TeV electron beams in future linear colliders

  1. Radiation-induced myocardial perfusion abnormalities in breast cancer patients following external beam radiation therapy

    Directory of Open Access Journals (Sweden)

    Mohammad Eftekhari

    2015-01-01

    Full Text Available Objective(s: Radiation therapy for breast cancer can induce myocardial capillary injury and increase cardiovascular morbidity and mortality. A prospective cohort was conducted to study the prevalence of myocardial perfusion abnormalities following radiation therapy of left-sided breast cancer patients as compared to those with right–sided cancer. Methods: To minimize potential confounding factors, only those patients with low 10-year risk of coronary artery disease (based on Framingham risk scoring were included. All patients were initially treated by modified radical mastectomy and then were managed by postoperative 3D Conformal Radiation Therapy (CRT to the surgical bed with an additional 1-cm margin, delivered by 46-50 Gy (in 2 Gy daily fractions over a 5-week course. The same dose-adjusted chemotherapy regimen (including anthracyclines, cyclophosphamide and taxol was given to all patients. Six months after radiation therapy, all patients underwent cardiac SPECT for the evaluation of myocardial perfusion. Results: A total of 71 patients with a mean age of 45.3±7.2 years [35 patients with leftsided breast cancer (exposed and 36 patients with right-sided cancer (controls] were enrolled. Dose-volume histogram (DVH [showing the percentage of the heart exposed to >50% of radiation] was significantly higher in patients with left-sided breast cancer. Visual interpretation detected perfusion abnormalities in 42.9% of cases and 16.7% of controls (P=0.02, Odds ratio=1.46. In semiquantitative segmental analysis, only apical (28.6% versus 8.3%, P=0.03 and anterolateral (17.1% versus 2.8%, P=0.049 walls showed significantly reduced myocardial perfusion in the exposed group. Summed Stress Score (SSS of>3 was observed in twelve cases (34.3%, while in five of the controls (13.9%,(Odds ratio=1.3. There was no significant difference between the groups regarding left ventricular ejection fraction. Conclusion: The risk of radiation induced myocardial

  2. Effect of incident beam and diffuse radiation on par absorption, photosynthesis and transpiration of sitka spruce - a simulation study

    International Nuclear Information System (INIS)

    A simulation model, Maestro, is used to study the influence of beam fraction in the incident radiation and the radiance distribution of the sky diffuse radiation on PAR absorption, photosynthesis and transpiration of a Sitka spruce (Picea sitchensis (Bong.) Carr) tree crown. It is concluded that inaccurate separation of beam and diffuse radiation leads to significant errors in estimating the amounts of PAR absorbed, photosynthesis and transpiration by a tree in the stand. Much more attention should be paid to adequate descriptions of the radiance distribution of the sky diffuse radiation under different sky conditions. A useful approach is proposed for simulating the incident global radiaiton in a physiological, process-based model

  3. Intense microwave radiation from a repetitive backward-wave oscillator driven by a relativistic electron beam

    International Nuclear Information System (INIS)

    High-power microwaves (20--50 MW, 8.8 GHz) have been produced in repetitive pulses at a rate of 10 Hz in a joint experiment by Harry Diamond Laboratories and Sandia National Laboratories. These microwaves were produced with Harry Diamond Laboratories' backward-wave oscillator (BWO), driven by a 600 to 800-kV, 2-kA electron beam, which was guided by a magnetic field of variable strength from 0.75 to 1.05 T. The beam was produced with Sandia National Laboratories' repetitive high-voltage pulser, RAVEN. Microwave diagnostic instrumentation included a directional coupler, heterodyne receiver, dispersive waveguide delay line, and calorimeter. In a train of 10 pulses, the shape, duration, and amplitude of the injection voltage and beam current remained unchanged for each individual pulse. The intensity of the final microwave pulse was 40% of the first pulse, and the final pulse was 80% as long as the first. The basic pulse shape remained unchanged. More intense microwave radiation should be obtained with a higher magnetic field. Computer simulations using the code magic predicted the characteristic dip in the magnetic field strength versus microwave power output curve. Code predictions of microwave power output with a warm beam agree very well with experimental results. Finally, cyclotron resonance is presented in a descriptive fashion to account for the power output dip. This is the first experiment with a repetitively pulsed high-power BWO driven by a relativistic electron beam performed outside the USSR

  4. Dosimetric predictors of biochemical control of prostate cancer in patients randomised to external beam radiotherapy with a boost of high dose rate brachytherapy

    International Nuclear Information System (INIS)

    Background: To correlate dose and volume dosimetric parameters (D90 and V100) with biochemical control in advanced prostate cancer treated with high-dose rate brachytherapy (HDR-BT). Methods: One hundred and eight patients received external beam radiotherapy (EBRT) to 35.75 Gy in 13 fractions followed by HDR-BT of 2 × 8.5 Gy. Kaplan–Meier freedom-from-biochemical relapse (FFbR; nadir + 2 μg/L) fits were grouped by the first (Q1), second (Q2) and third (Q3) D90 and V100 quartiles. Groups were compared with the log-rank test. Univariate and multivariate Hazard Ratios (HR) for D90 and V100 and other co-variates (PSA, androgen deprivation therapy (ADT) were obtained using Cox’s proportional hazard model. Results: FFbR was significantly higher in patients whose D90 and V100 were at or above the second and third quartile (log rank p ⩽ 0·04). In multivariate analysis D90, V100 were significant covariates for risk of relapse. Conclusions: Dichotomising the data using 6 levels of response (above and below Q1, Q2 and Q3) showed a progressive and continuous improvement in biochemical control of disease across the entire dose (and volume) range. The data show that a minimum D90 of 108% of the prescribed dose should be the target to achieve

  5. Evaluation of parotid function using dynamic parotid scintigraphy in nasopharyngeal carcinoma patients treated with external beam radiation therapy

    International Nuclear Information System (INIS)

    Objective: To evaluation of the parotid function using dynamic parotid scintigraphy in nasopharyngeal carcinoma patients treated with external beam radiation therapy. Methods: Twenty-one nasopharyngeal carcinoma patients were included into this study. Dynamic parotid scintigraphy was performed before and after external beam radiation therapy. Semi-quantitative parameters of parotid (uptake index, excretion rate and excretion index) was used to evaluate the changes of parotid function. Results: UI, ER and EI of parotid were decreased markedly after external beam radiation therapy, t is 56.65, 41.34, 30.69 respectively, P<0.001. The uptake and excretion function of the parotid were all impaired, which correlated with the dray mouth symptom of the patients. Conclusion: Dynamic parotid scintigraphy can play a key role in the evaluation of parotid function in nasopharyngeal carcinoma patients treated with external beam radiation therapy. (authors)

  6. Beam and radiation tests of a fast, warm liquid open-quotes swimming poolclose quotes calorimeter

    International Nuclear Information System (INIS)

    A fast, warm liquid calorimeter module with lead absorber immersed in tetramethyl pentane (TMP) as the liquid medium (i.e. a open-quotes swimming poolclose quotes configuration) has been built and tested in a high energy beam at FNAL, and exposed to intense radiation from a strong Co60 source. A two-tower prototype, incorporating the concept of the electrostatic transformer for fast readout, exhibited very good uniformity and small cross-talk in the beam test. This same calorimeter was exposed to over 10 Mrad of radiation from the Co60 source, and the electron drift lifetime was measured as a function of accumulated dose. The lifetime improved significantly with small doses of radiation, up to a few hundred krad, then decreased gradually at higher doses, and extrapolated to a minimum useful lifetime of 0.1 μs at over 150 Mrad. This result was confirmed by measurements on a small single-electrode test cell which was irradiated to more than 25 Mrad. In this case, the lifetime decreased from 10μs to 0.1 μs when extrapolated to a dose of over 600 Mrad. This cell was also used to measure the effect of positive ion open-quotes space chargeclose quotes buildup under intense radiation. The results suggest that such effects are small even at the highest intensity available, about 1.3 Mrad/day, for applied fields ≥25 kV/cm

  7. A white-beam fast-shutter for microbeam radiation therapy at the ESRF

    CERN Document Server

    Renier, M; Nemoz, C; Thomlinson, W

    2002-01-01

    The ID17 Medical Beamline port at the European Synchrotron Radiation Facility (ESRF) delivers white beam generated by a 1.4 T wiggler. It is devoted to medical applications of synchrotron radiation. One major program of the beamline is called Microbeam Radiation Therapy (MRT). In this radiotherapy technique, still under development, the white beam fan is divided into several microbeams before reaching the target which is a tumoral brain. The maximum skin-entrance absorbed dose can reach extremely high values (over 1000 Gy) before causing tissue necrosis, while causing tumor necrosis. One of the key parameters for the success of the MRT is the accurate control of the radiation dose delivered to the target, as well as its location with respect to the tumor, to prevent unnecessary damage to normal tissues. Therefore, the opening and closing positions of the shutter while the target is moving vertically at a constant speed reaching 150 mm/s must be carefully controlled. Shutter opening times as short as 5+-0.5 ms...

  8. Verification of the alignment of a therapeutic radiation beam relative to its patient positioner.

    Science.gov (United States)

    Barkhof, J; Schut, G; Flanz, J B; Goitein, M; Schippers, J M

    1999-11-01

    An easily-used system has been developed for routine measurements of the alignment of beams used for radiation therapy. The position of a beam of circular cross section is measured with respect to a steel sphere fixed to the patient positioning table and which should coincide with the isocenter. Since measurements can be done at all gantry angles (if one is available) and with all possible orientations of the patient table, the system is particularly suited for rapid and accurate measurements of gantry and/or couch isocentricity. Because it directly measures beam-to-positioner offset, the system provides an inclusive alignment verification of the total treatment system. The system has been developed for use with proton beams, but it could equally be used for alignment checks of an x-ray beam from a linear accelerator or other source. The measuring instrument consists of a scintillation screen viewed by a CCD camera, mounted on the gantry downstream of the sphere. The steel sphere is not large enough to stop protons of all energies of interest; however, it will always modify the energy and direction of protons which intersect it, creating a region of lower intensity (a "shadow") in the light spot created by the proton beam hitting the screen. The position of the shadow with respect to the light spot is a measure of the alignment of the system. An image-analysis algorithm has been developed for an automatic determination of the position of the shadow with respect to the light spot. The specifications and theoretical analysis of the system have been derived from Monte Carlo simulations, which are validated by measurements. We have demonstrated that the device detects beam misalignments with an accuracy (1 s.d.) of 0.05 mm, which is in agreement with the expected performance. This accuracy is more than sufficient to detect the maximum allowed misalignment of +/-0.5 mm. PMID:10587228

  9. Installation And Test Of Electron Beam Generation System To Produce Far-Infrared Radiation And X-Ray Pulses

    International Nuclear Information System (INIS)

    SURIYA project at the Fast Neutron Research Facility, Chiang Mai University, aims to establish a facility to generate femtosecond electron beams. This electron beam can be used to generate high intensity far-infrared radiation and ultra-short X-ray pulses. The main components of the system are a 3 MeV RF electron gun with a thermionic cathode, an a-magnet as a bunch compressor, and post acceleration 15-20 MeV by a linear accelerator (linac). Between the main components, there are focusing quadrupole magnets and steering magnets to maintain the electron beam within a high vacuum tube. At the end of the beam transport line, a dipole magnet has been installed to function as a beam dump and an energy spectrometer. After the installation and testing of individual major components were completed, we have been investigating the generation of the electron beam, intense far- infrared radiation and ultra short X-ray pulses

  10. Radiation grafting of styrene onto polypropylene fibres by a 10 MeV electron beam

    International Nuclear Information System (INIS)

    The radiation-induced graft copolymerization is an effective method for modification of the chemical and physical properties of polypropylene. Graft copolymerization of styrene onto polypropylene fibers has been studied by simultaneous irradiation method, using a 10 MeV electron beam. Samples were irradiated in an environment of nitrogen gas. The effects of radiation dose and styrene concentration in methanol, on the grafting yield were investigated. The effects of polyfunctional monomer, i.e., trimethylopropane trimethacrylate (TMPTMA) and acid (sulfuric acid) on the grafting yield were also examined. The grafted samples were then sulfonated and allowed to react with solution of a basic dye. The samples were characterized by mechanical properties and thermal stability. The mechanical properties of the radiated samples were reduced and the grafted samples had lower mechanical properties

  11. Signatures of quantum radiation reaction in laser-electron-beam collisions

    International Nuclear Information System (INIS)

    Electron dynamics in the collision of an electron beam with a high-intensity focused ultrashort laser pulse are investigated using three-dimensional QED particle-in-cell (PIC) simulations, and the results are compared with those calculated by classical Landau and Lifshitz PIC simulations. Significant differences are observed from the angular dependence of the electron energy distribution patterns for the two different approaches, because photon emission is no longer well approximated by a continuous process in the quantum radiation-dominated regime. The stochastic nature of photon emission results in strong signatures of quantum radiation-reaction effects under certain conditions. We show that the laser spot size and duration greatly influence these signatures due to the competition of QED effects and the ponderomotive force, which is well described in the classical approximation. The clearest signatures of quantum radiation reaction are found in the limit of large laser spots and few cycle pulse durations

  12. Acoustic radiation force on a double-layer microsphere by a Gaussian focused beam

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Rongrong; Cheng, Kaixuan; Liu, Jiehui; Mao, Yiwei; Gong, Xiufen [Key Laboratory of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Liu, Xiaozhou, E-mail: xzliu@nju.edu.cn [Key Laboratory of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-10-14

    A new model for calculating the radiation force on double-layer microsphere is proposed based on the ray acoustics approach. The axial acoustic radiation force resulting from a focused Gaussian beam incident on spherical shells immersed in water is examined theoretically in relation to its thickness and the contents of its double-layer. The attenuation both in the water and inside the sphere is considered in this method, which cannot be ignored while the high frequency ultrasonic is used. Results of numerical calculations are presented for fat and low density polyethylene materials, with the hollow region filled with animal oil, water, or air. These results show how the acoustic impedance and the sound velocity of both layers, together with the thickness of the shell, affect the acoustic radiation force.

  13. The use of different type of electron beam radiation equipment for biotechnological materials

    International Nuclear Information System (INIS)

    The potential of using electron beam radiation and bremsstrahlung for some biotechnological materials treatment is presented based on the results of the R and D programme established in 1993 at the Institute of Lasers, Plasma and Radiation Physics Bucharest, Electron Accelerator Laboratory. The main parameters of different electron accelerator types used to process biotechnological materials are presented as these machines were designed, developed and improved. In order to fulfil the radiation processing requirements for biotechnology and environmental protection, betatron, linear and microtron-type electron accelerators are considered and there is an interest to develop a dedicated one as well. The results of irradiation of different biotechnological items as cell cultures, microbial strains, enzymes and biopreparates and cellulose-based wastes are presented

  14. Belle-II VXD radiation monitoring and beam abort with sCVD diamond sensors

    Science.gov (United States)

    Adamczyk, K.; Aihara, H.; Angelini, C.; Aziz, T.; Babu, V.; Bacher, S.; Bahinipati, S.; Barberio, E.; Baroncelli, T.; Basith, A. K.; Batignani, G.; Bauer, A.; Behera, P. K.; Bergauer, T.; Bettarini, S.; Bhuyan, B.; Bilka, T.; Bosi, F.; Bosisio, L.; Bozek, A.; Buchsteiner, F.; Casarosa, G.; Ceccanti, M.; Červenkov, D.; Chendvankar, S. R.; Dash, N.; Divekar, S. T.; Doležal, Z.; Dutta, D.; Forti, F.; Friedl, M.; Hara, K.; Higuchi, T.; Horiguchi, T.; Irmler, C.; Ishikawa, A.; Jeon, H. B.; Joo, C.; Kandra, J.; Kang, K. H.; Kato, E.; Kawasaki, T.; Kodyš, P.; Kohriki, T.; Koike, S.; Kolwalkar, M. M.; Kvasnička, P.; Lanceri, L.; Lettenbicher, J.; Mammini, P.; Mayekar, S. N.; Mohanty, G. B.; Mohanty, S.; Morii, T.; Nakamura, K. R.; Natkaniec, Z.; Negishi, K.; Nisar, N. K.; Onuki, Y.; Ostrowicz, W.; Paladino, A.; Paoloni, E.; Park, H.; Pilo, F.; Profeti, A.; Rashevskaya, I.; Rao, K. K.; Rizzo, G.; Rozanska, M.; Sandilya, S.; Sasaki, J.; Sato, N.; Schultschik, S.; Schwanda, C.; Seino, Y.; Shimizu, N.; Stypula, J.; Tanaka, S.; Tanida, K.; Taylor, G. N.; Thalmeier, R.; Thomas, R.; Tsuboyama, T.; Uozumi, S.; Urquijo, P.; Vitale, Lorenzo; Volpi, M.; Watanuki, S.; Watson, I. J.; Webb, J.; Wiechczynski, J.; Williams, S.; Würkner, B.; Yamamoto, H.; Yin, H.; Yoshinobu, T.

    2016-07-01

    The Belle-II VerteX Detector (VXD) has been designed to improve the performances with respect to Belle and to cope with an unprecedented luminosity of 8 ×1035cm-2s-1 achievable by the SuperKEKB. Special care is needed to monitor both the radiation dose accumulated throughout the life of the experiment and the instantaneous radiation rate, in order to be able to promptly react to sudden spikes for the purpose of protecting the detectors. A radiation monitoring and beam abort system based on single-crystal diamond sensors is now under an active development for the VXD. The sensors will be placed in several key positions in the vicinity of the interaction region. The severe space limitations require a challenging remote readout of the sensors.

  15. Signatures of quantum radiation reaction in laser-electron-beam collisions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H. Y. [Helmholtz Institute Jena, Fröbelstieg 3, 07743 Jena (Germany); Yan, X. Q. [State Key Laboratory of Nuclear Physics and Technology, and Key Lab of High Energy Density Physics Simulation, CAPT, Peking University, Beijing 100871 (China); Zepf, M., E-mail: m.zepf@uni-jena.de [Helmholtz Institute Jena, Fröbelstieg 3, 07743 Jena (Germany); School of Mathematics and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom)

    2015-09-15

    Electron dynamics in the collision of an electron beam with a high-intensity focused ultrashort laser pulse are investigated using three-dimensional QED particle-in-cell (PIC) simulations, and the results are compared with those calculated by classical Landau and Lifshitz PIC simulations. Significant differences are observed from the angular dependence of the electron energy distribution patterns for the two different approaches, because photon emission is no longer well approximated by a continuous process in the quantum radiation-dominated regime. The stochastic nature of photon emission results in strong signatures of quantum radiation-reaction effects under certain conditions. We show that the laser spot size and duration greatly influence these signatures due to the competition of QED effects and the ponderomotive force, which is well described in the classical approximation. The clearest signatures of quantum radiation reaction are found in the limit of large laser spots and few cycle pulse durations.

  16. Disinfestation of agricultural products with electron beams and their radiation tolerance

    International Nuclear Information System (INIS)

    Some agricultural products contaminated with insect pests are fumigated with methyl bromide for quarantine purposes. However, the use of methyl bromide is preferably restricted because of its ozone depleting effect. Therefore, establishing alternative quarantine techniques is highly desirable; one such technique is exposure to ionizing radiation. Few data are available on the effects of radiation on insect pests other than fruit flies and stored-product insects and on the radiation tolerance of host commodities. Radiation technology as an alternative to methyl bromide fumigation will be used to inactivate not only insects but also mites, spider mites, thrips, nematodes, scales, mealybugs and thrips contaminating fruits, grains, cut flowers, vegetables, timbers, seedlings and seeds. In order to collect data on the effects of irradiation on pests and host commodities, IAEA and FAO have conducted an international project, 'FAO/IAEA Coordinated Research Programme on Irradiation as a Quarantine Treatment of Mites, Nematodes and Insects other than Fruit Fly' since 1992. The project determines the minimum doses necessary to inactivate pests and the maximum doses host commodities tolerate. All pests except nematodes can be inactivated at doses 400Gy or lower. Various varieties of cut flowers and herbs are tolerant to 400Gy of radiation, although some flowers and herbs such as chrysanthemum, rose, lily, calla, anthurium, sweet pea, iris, dill, basil and arugula are intolerant to 200Gy of radiation. Japanese research project on treatment of cut flowers with electron beams carried out mainly by Yokohama Plant Protection Station greatly contributes to these conclusions. Aqueous solution (2%) of sucrose, glucose, fructose or maltose prevents radiation-induced detrimental effects of radiation on chrysanthemums. Sugars reduce radiation-induced physiological deterioration of chrysanthemums. (author)

  17. Effect on the insulation material of a MOSFET device submitted to a standard diagnostic radiation beam

    International Nuclear Information System (INIS)

    MOSFET electronic devices have been used for dosimetry in radiology and radiotherapy. Several communications show that due to the radiation exposure defects appear on the semiconductor crystal lattice. Actually, the structure of a MOSFET consists of three materials: a semiconductor, a metal and an insulator between them. The MOSFET is a quadripolar device with a common terminal: gate-source is the input; drain-source is the output. The gate controls the electrical current passing through semiconductor medium by the field effect because the silicon oxide acts as insulating material. The proposal of this work is to show some radiation effects on the insulator of a MOSFET device. A 6430 Keithley sub-femtoamp SourceMeter was used to verify how the insulating material layer in the structure of the device varies with the radiation exposure. We have used the IEC 61267 standard radiation X-ray beams generated from a Pantak industrial unit in the radiation energy range of computed tomography. This range was chosen because we are using the MOSFET device as radiation detector for dosimetry in computed tomography. The results showed that the behaviour of the electrical current of the device is different in the insulator and semiconductor structures.

  18. Dynamic mechanical studies on epoxy resins cured by electron beam radiation

    International Nuclear Information System (INIS)

    Dynamic mechanical analyses on electron beam (EB)-cured epoxy resins were made in the paper. Through the studies on variation rules of gel fraction, tan δ and storage modulus for varied samples, the important effects of EB radiation dosage, initiator dosage, chemical structure, molecular weight and distribution, and heat treatment on curing reaction and properties of epoxy resin systems have been obtained. Under low radiation doses, the gel fraction, glass transition temperature (Tg) and high temperature modulus of cured epoxy resin increase with increasing radiation dose and initiator dosage. The crosslinking density of epoxy resin decreases slightly with increasing molecular weight. When radiation doses increase, the molecular weight has a little influence on the increasing of curing level and an optimal dosage of initiator appears. The experimental results indicate that the radiation reactivity of epoxy resins is directly associated with their chemical structures. Under the same radiation dose, the reaction extent in sample with high polydispersity is higher than that in low polydispersity sample, but the degree of homogeneity in crosslinking structure is lower. When the EB-cured epoxy resin is heated, the crosslinking density is enhanced. If the temperature of heating treatment exceeds the thermal-initiating temperature of initiator, the local thermal-crosslinking network can be formed in resin system

  19. Effect on the insulation material of a MOSFET device submitted to a standard diagnostic radiation beam

    Energy Technology Data Exchange (ETDEWEB)

    De Magalhaes, C M S; Dos Santos, L A P; Souza, D do N; Maia, A F, E-mail: cinthiamsm@yahoo.com.b

    2010-11-01

    MOSFET electronic devices have been used for dosimetry in radiology and radiotherapy. Several communications show that due to the radiation exposure defects appear on the semiconductor crystal lattice. Actually, the structure of a MOSFET consists of three materials: a semiconductor, a metal and an insulator between them. The MOSFET is a quadripolar device with a common terminal: gate-source is the input; drain-source is the output. The gate controls the electrical current passing through semiconductor medium by the field effect because the silicon oxide acts as insulating material. The proposal of this work is to show some radiation effects on the insulator of a MOSFET device. A 6430 Keithley sub-femtoamp SourceMeter was used to verify how the insulating material layer in the structure of the device varies with the radiation exposure. We have used the IEC 61267 standard radiation X-ray beams generated from a Pantak industrial unit in the radiation energy range of computed tomography. This range was chosen because we are using the MOSFET device as radiation detector for dosimetry in computed tomography. The results showed that the behaviour of the electrical current of the device is different in the insulator and semiconductor structures.

  20. Enacting laws concerning radiation safety management for students using X-rays and electron beams under 1 MeV

    International Nuclear Information System (INIS)

    Laws concerning radiation safety management were analyzed from the point of view of defining precisely what is meant by radiation and what is meant by the subject. There are no laws to protect students from radiation hazards when using X-rays and electron beams under 1 MeV for research and/or education. The Law concerning Technical Standards for Preventing Radiation Hazards gives the authorities the power to enact new rules and regulations that will protect the students. The Radiation Council must take charge for enactment of all laws regarding radiation safety management. (author)

  1. eBooking of beam-time over internet for beamlines of Indus synchrotron radiation sources

    International Nuclear Information System (INIS)

    Users from various research labs and academic institutes carry out experiments on beamlines of two Synchrotron Radiation Sources Indus-1 and Indus-2 available at RRCAT, Indore. To carry out experimental work on beamlines of both synchrotron radiation sources, beam-time is booked over Internet by the users of beamlines using user portal designed, developed and deployed over Internet. This portal has made the process of beamtime booking fast, hassle free and paperless as manual booking of beam-time for carrying out experiment on a particular beamline is cumbersome. The portal facilitates in-charge of Indus-1 and Indus-2 beamlines to keep track of users' records, work progress and other activities linked to experiments carried on beamlines. It is important to keep record and provide statistics about the usage of the beam lines from time-to-time. The user portal for e-booking of beam-time has been developed in-house using open source software development tools. Multi-step activities of users and beamline administrators are workflow based with seamless flow of information across various modules and fully authenticated using role based mechanism for different roles of software usage. The software is in regular use since November 2013 and has helped beamline in- charges in efficiently managing various activities related to user registration, booking of beam-time, booking of Guest House, Generation of Security permits, User feedback etc. Design concept, role based authentication mechanism and features provided by the web portal are discussed in detail in this paper. (author)

  2. Beam transport radiation shielding for branch lines 2-ID-B and 2-ID-C

    International Nuclear Information System (INIS)

    The x-ray radiation shielding requirements beyond the first optics enclosure have been considered for the beam transport of the 2-ID-B and 2-ID-C branch lines of Sector 2 (SRI-CAT) of the APS. The first three optical components (mirrors) of the 2-ID-B branch are contained within the shielded first optics enclosure. Calculations indicate that scattering of the primary synchrotron beam by beamline components outside the enclosure, such as apertures and monochromators, or by gas particles in case of vacuum failure is within safe limits for this branch. A standard 2.5-inch-diameter stainless steel pipe with 1/16-inch-thick walls provides adequate shielding to reduce the radiation dose equivalent rate to human tissue to below the maximum permissible limit of 0.25 mrem/hr. The 2-ID-C branch requires, between the first optics enclosure where only two mirrors are used and the housing for the third mirror, additional lead shielding (0.75 mm) and a minimum approach distance of 2.6 cm. A direct beam stop consisting of at least 4.5 mm of lead is also required immediately downstream of the third mirror for 2-ID-C. Finally, to stop the direct beam from escaping the experimental station, a beam stop consisting of at least 4-mm or 2.5-mm steel is required for the 2-ID-B or 2-ID-C branches, respectively. This final requirement can be met by the vacuum chambers used to house the experiments for both branch lines

  3. Beam angle optimization for intensity-modulated radiation therapy using a guided pattern search method

    Science.gov (United States)

    Rocha, Humberto; Dias, Joana M.; Ferreira, Brígida C.; Lopes, Maria C.

    2013-05-01

    Generally, the inverse planning of radiation therapy consists mainly of the fluence optimization. The beam angle optimization (BAO) in intensity-modulated radiation therapy (IMRT) consists of selecting appropriate radiation incidence directions and may influence the quality of the IMRT plans, both to enhance better organ sparing and to improve tumor coverage. However, in clinical practice, most of the time, beam directions continue to be manually selected by the treatment planner without objective and rigorous criteria. The goal of this paper is to introduce a novel approach that uses beam’s-eye-view dose ray tracing metrics within a pattern search method framework in the optimization of the highly non-convex BAO problem. Pattern search methods are derivative-free optimization methods that require a few function evaluations to progress and converge and have the ability to better avoid local entrapment. The pattern search method framework is composed of a search step and a poll step at each iteration. The poll step performs a local search in a mesh neighborhood and ensures the convergence to a local minimizer or stationary point. The search step provides the flexibility for a global search since it allows searches away from the neighborhood of the current iterate. Beam’s-eye-view dose metrics assign a score to each radiation beam direction and can be used within the pattern search framework furnishing a priori knowledge of the problem so that directions with larger dosimetric scores are tested first. A set of clinical cases of head-and-neck tumors treated at the Portuguese Institute of Oncology of Coimbra is used to discuss the potential of this approach in the optimization of the BAO problem.

  4. Beam angle optimization for intensity-modulated radiation therapy using a guided pattern search method

    International Nuclear Information System (INIS)

    Generally, the inverse planning of radiation therapy consists mainly of the fluence optimization. The beam angle optimization (BAO) in intensity-modulated radiation therapy (IMRT) consists of selecting appropriate radiation incidence directions and may influence the quality of the IMRT plans, both to enhance better organ sparing and to improve tumor coverage. However, in clinical practice, most of the time, beam directions continue to be manually selected by the treatment planner without objective and rigorous criteria. The goal of this paper is to introduce a novel approach that uses beam’s-eye-view dose ray tracing metrics within a pattern search method framework in the optimization of the highly non-convex BAO problem. Pattern search methods are derivative-free optimization methods that require a few function evaluations to progress and converge and have the ability to better avoid local entrapment. The pattern search method framework is composed of a search step and a poll step at each iteration. The poll step performs a local search in a mesh neighborhood and ensures the convergence to a local minimizer or stationary point. The search step provides the flexibility for a global search since it allows searches away from the neighborhood of the current iterate. Beam’s-eye-view dose metrics assign a score to each radiation beam direction and can be used within the pattern search framework furnishing a priori knowledge of the problem so that directions with larger dosimetric scores are tested first. A set of clinical cases of head-and-neck tumors treated at the Portuguese Institute of Oncology of Coimbra is used to discuss the potential of this approach in the optimization of the BAO problem. (paper)

  5. SU-E-T-596: Axillary Nodes Radiotherapy Boost Field Dosimetric Impact Study: Oblique Field and Field Optimization in 3D Conventional Breast Cancer Radiation Treatment

    International Nuclear Information System (INIS)

    Purpose: To evaluate dosimetric impact of two axillary nodes (AX) boost techniques: (1) posterior-oblique optimized field boost (POB), (2) traditional posterior-anterior boost (PAB) with field optimization (O-PAB), for a postmastectomy breast patient with positive axillary lymph nodes. Methods: Five patients, 3 left and 2 right chest walls, were included in this study. All patients were simulated in 5mm CT slice thickness. Supraclavicular (SC) and level I/II/III AX were contoured based on the RTOG atlas guideline. Five treatment plans, (1) tangential chest wall, (2) oblique SC including AX, (3) PAB, O-PAB and POB, were created for each patient. Three plan sums (PS) were generated by sum one of (3) plan with plan (1) and (2). The field optimization was done through PS dose distribution, which included a field adjustment, a fractional dose, a calculation location and a gantry angle selection for POB. A dosimetric impact was evaluated by comparing a SC and AX coverage, a PS maximum dose, an irradiated area percentage volume received dose over 105% prescription dose (V105), an ipsi-laterial mean lung dose (MLD), an ipsi-laterial mean humeral head dose (MHHD), a mean heart dose (MHD) (for left case only) and their DVH amount these three technique. Results: O-PAB, POB and PAB dosimetric results showed that there was no significant different on SC and AX coverage (p>0.43) and MHD (p>0.16). The benefit of sparing lung irradiation from PAB to O-PAB to POB was significant (p<0.004). PAB showed a highest PS maximum dose (p<0.005), V105 (p<0.023) and MLD (compared with OPAB, p=0.055). MHHD showed very sensitive to the patient arm positioning and anatomy. O-PAB convinced a lower MHHD than PAB (p=0.03). Conclusion: 3D CT contouring plays main role in accuracy radiotherapy. Dosimetric advantage of POB and O-PAB was observed for a better normal tissue irradiation sparing

  6. SU-E-T-596: Axillary Nodes Radiotherapy Boost Field Dosimetric Impact Study: Oblique Field and Field Optimization in 3D Conventional Breast Cancer Radiation Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Su, M [Mount Sinai School of Medicine, Elmhurst, NY (United States); Sura, S

    2014-06-01

    Purpose: To evaluate dosimetric impact of two axillary nodes (AX) boost techniques: (1) posterior-oblique optimized field boost (POB), (2) traditional posterior-anterior boost (PAB) with field optimization (O-PAB), for a postmastectomy breast patient with positive axillary lymph nodes. Methods: Five patients, 3 left and 2 right chest walls, were included in this study. All patients were simulated in 5mm CT slice thickness. Supraclavicular (SC) and level I/II/III AX were contoured based on the RTOG atlas guideline. Five treatment plans, (1) tangential chest wall, (2) oblique SC including AX, (3) PAB, O-PAB and POB, were created for each patient. Three plan sums (PS) were generated by sum one of (3) plan with plan (1) and (2). The field optimization was done through PS dose distribution, which included a field adjustment, a fractional dose, a calculation location and a gantry angle selection for POB. A dosimetric impact was evaluated by comparing a SC and AX coverage, a PS maximum dose, an irradiated area percentage volume received dose over 105% prescription dose (V105), an ipsi-laterial mean lung dose (MLD), an ipsi-laterial mean humeral head dose (MHHD), a mean heart dose (MHD) (for left case only) and their DVH amount these three technique. Results: O-PAB, POB and PAB dosimetric results showed that there was no significant different on SC and AX coverage (p>0.43) and MHD (p>0.16). The benefit of sparing lung irradiation from PAB to O-PAB to POB was significant (p<0.004). PAB showed a highest PS maximum dose (p<0.005), V105 (p<0.023) and MLD (compared with OPAB, p=0.055). MHHD showed very sensitive to the patient arm positioning and anatomy. O-PAB convinced a lower MHHD than PAB (p=0.03). Conclusion: 3D CT contouring plays main role in accuracy radiotherapy. Dosimetric advantage of POB and O-PAB was observed for a better normal tissue irradiation sparing.

  7. Imaging Changes in Pediatric Intracranial Ependymoma Patients Treated With Proton Beam Radiation Therapy Compared to Intensity Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Gunther, Jillian R. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Sato, Mariko; Chintagumpala, Murali [Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Texas Children' s Cancer Center, Houston, Texas (United States); Ketonen, Leena [Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Jones, Jeremy Y. [Department of Pediatric Radiology, Texas Children' s Hospital, Houston, Texas (United States); Allen, Pamela K. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Paulino, Arnold C. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Texas Children' s Cancer Center, Houston, Texas (United States); Okcu, M. Fatih; Su, Jack M. [Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Texas Children' s Cancer Center, Houston, Texas (United States); Weinberg, Jeffrey [Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Boehling, Nicholas S. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Khatua, Soumen [Department of Pediatrics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Adesina, Adekunle [Department of Pathology, Baylor College of Medicine, Texas Children' s Hospital, Houston, Texas (United States); Dauser, Robert; Whitehead, William E. [Department of Neurosurgery, Texas Children' s Hospital, Houston, Texas (United States); Mahajan, Anita, E-mail: amahajan@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2015-09-01

    Purpose: The clinical significance of magnetic resonance imaging (MRI) changes after radiation therapy (RT) in children with ependymoma is not well defined. We compared imaging changes following proton beam radiation therapy (PBRT) to those after photon-based intensity modulated RT (IMRT). Methods and Materials: Seventy-two patients with nonmetastatic intracranial ependymoma who received postoperative RT (37 PBRT, 35 IMRT) were analyzed retrospectively. MRI images were reviewed by 2 neuroradiologists. Results: Sixteen PBRT patients (43%) developed postradiation MRI changes at 3.8 months (median) with resolution by 6.1 months. Six IMRT patients (17%) developed changes at 5.3 months (median) with 8.3 months to resolution. Mean age at radiation was 4.4 and 6.9 years for PBRT and IMRT, respectively (P=.06). Age at diagnosis (>3 years) and time of radiation (≥3 years) was associated with fewer imaging changes on univariate analysis (odds ratio [OR]: 0.35, P=.048; OR: 0.36, P=.05). PBRT (compared to IMRT) was associated with more frequent imaging changes, both on univariate (OR: 3.68, P=.019) and multivariate (OR: 3.89, P=.024) analyses. Seven (3 IMRT, 4 PBRT) of 22 patients with changes had symptoms requiring intervention. Most patients were treated with steroids; some PBRT patients also received bevacizumab and hyperbaric oxygen therapy. None of the IMRT patients had lasting deficits, but 2 patients died from recurrent disease. Three PBRT patients had persistent neurological deficits, and 1 child died secondarily to complications from radiation necrosis. Conclusions: Postradiation MRI changes are more common with PBRT and in patients less than 3 years of age at diagnosis and treatment. It is difficult to predict causes for development of imaging changes that progress to clinical significance. These changes are usually self-limiting, but some require medical intervention, especially those involving the brainstem.

  8. Imaging Changes in Pediatric Intracranial Ependymoma Patients Treated With Proton Beam Radiation Therapy Compared to Intensity Modulated Radiation Therapy

    International Nuclear Information System (INIS)

    Purpose: The clinical significance of magnetic resonance imaging (MRI) changes after radiation therapy (RT) in children with ependymoma is not well defined. We compared imaging changes following proton beam radiation therapy (PBRT) to those after photon-based intensity modulated RT (IMRT). Methods and Materials: Seventy-two patients with nonmetastatic intracranial ependymoma who received postoperative RT (37 PBRT, 35 IMRT) were analyzed retrospectively. MRI images were reviewed by 2 neuroradiologists. Results: Sixteen PBRT patients (43%) developed postradiation MRI changes at 3.8 months (median) with resolution by 6.1 months. Six IMRT patients (17%) developed changes at 5.3 months (median) with 8.3 months to resolution. Mean age at radiation was 4.4 and 6.9 years for PBRT and IMRT, respectively (P=.06). Age at diagnosis (>3 years) and time of radiation (≥3 years) was associated with fewer imaging changes on univariate analysis (odds ratio [OR]: 0.35, P=.048; OR: 0.36, P=.05). PBRT (compared to IMRT) was associated with more frequent imaging changes, both on univariate (OR: 3.68, P=.019) and multivariate (OR: 3.89, P=.024) analyses. Seven (3 IMRT, 4 PBRT) of 22 patients with changes had symptoms requiring intervention. Most patients were treated with steroids; some PBRT patients also received bevacizumab and hyperbaric oxygen therapy. None of the IMRT patients had lasting deficits, but 2 patients died from recurrent disease. Three PBRT patients had persistent neurological deficits, and 1 child died secondarily to complications from radiation necrosis. Conclusions: Postradiation MRI changes are more common with PBRT and in patients less than 3 years of age at diagnosis and treatment. It is difficult to predict causes for development of imaging changes that progress to clinical significance. These changes are usually self-limiting, but some require medical intervention, especially those involving the brainstem

  9. cExternal beam radiation results in minimal changes in post void residual urine volumes during the treatment of clinically localized prostate cancer

    Directory of Open Access Journals (Sweden)

    Wallner Kent E

    2009-07-01

    Full Text Available Abstract Background To evaluate the impact of external beam radiation therapy (XRT on weekly ultrasound determined post-void residual (PVR urine volumes in patients with prostate cancer. Methods 125 patients received XRT for clinically localized prostate cancer. XRT was delivered to the prostate only (n = 66 or if the risk of lymph node involvement was greater than 10% to the whole pelvis followed by a prostate boost (n = 59. All patients were irradiated in the prone position in a custom hip-fix mobilization device with an empty bladder and rectum. PVR was obtained at baseline and weekly. Multiple clinical and treatment parameters were evaluated as predictors for weekly PVR changes. Results The mean patient age was 73.9 years with a mean pre-treatment prostate volume of 53.3 cc, a mean IPSS of 11.3 and a mean baseline PVR of 57.6 cc. During treatment, PVR decreased from baseline in both cohorts with the absolute difference within the limits of accuracy of the bladder scanner. Alpha-blockers did not predict for a lower PVR during treatment. There was no significant difference in mean PVR urine volumes or differences from baseline in either the prostate only or pelvic radiation groups (p = 0.664 and p = 0.458, respectively. Patients with a larger baseline PVR (>40 cc had a greater reduction in PVR, although the greatest reduction was seen between weeks one and three. Patients with a small PVR ( Conclusion Prostate XRT results in clinically insignificant changes in weekly PVR volumes, suggesting that radiation induced bladder irritation does not substantially influence bladder residual urine volumes.

  10. cExternal beam radiation results in minimal changes in post void residual urine volumes during the treatment of clinically localized prostate cancer

    International Nuclear Information System (INIS)

    To evaluate the impact of external beam radiation therapy (XRT) on weekly ultrasound determined post-void residual (PVR) urine volumes in patients with prostate cancer. 125 patients received XRT for clinically localized prostate cancer. XRT was delivered to the prostate only (n = 66) or if the risk of lymph node involvement was greater than 10% to the whole pelvis followed by a prostate boost (n = 59). All patients were irradiated in the prone position in a custom hip-fix mobilization device with an empty bladder and rectum. PVR was obtained at baseline and weekly. Multiple clinical and treatment parameters were evaluated as predictors for weekly PVR changes. The mean patient age was 73.9 years with a mean pre-treatment prostate volume of 53.3 cc, a mean IPSS of 11.3 and a mean baseline PVR of 57.6 cc. During treatment, PVR decreased from baseline in both cohorts with the absolute difference within the limits of accuracy of the bladder scanner. Alpha-blockers did not predict for a lower PVR during treatment. There was no significant difference in mean PVR urine volumes or differences from baseline in either the prostate only or pelvic radiation groups (p = 0.664 and p = 0.458, respectively). Patients with a larger baseline PVR (>40 cc) had a greater reduction in PVR, although the greatest reduction was seen between weeks one and three. Patients with a small PVR (<40 cc) had no demonstrable change throughout treatment. Prostate XRT results in clinically insignificant changes in weekly PVR volumes, suggesting that radiation induced bladder irritation does not substantially influence bladder residual urine volumes

  11. Radiative lifetimes in MoI using a novel atomic beam source

    International Nuclear Information System (INIS)

    Radiative lifetimes of the 4d5(a6S)5pz7P0 levels and the 4d5(a6S)5pz5P0 levels in MoI are reported as follows: tau(z7P04) = 15.9 ns, tau(z7P03) = 17.0 ns, tau(z7P02) = 17.1 ns, tau(z5P03) = 22.3 ns, tau(z5P02) = 22.1 ns, and tau(z5P01) = 21.7 ns (+-5%). The lifetimes are measured using time resolved laser induced fluorescence and a novel atomic beam source. This novel hollow cathode effusive beam source produces an intense beam of ground state Mo atoms and metastable Mo atoms. Our measurements on the z7P0 levels are in agreement with earlier lifetime measurements. Our measurements on the z5P0 levels are the first direct radiative lifetime measurements of these levels; the z5P0 measurements are of particular interest because the a5S → z5P0 multiplet is used to determine the solar abundance of Mo. (orig.)

  12. Improving the Fermilab Booster Notching Efficiency, Beam Losses and Radiation Levels

    Energy Technology Data Exchange (ETDEWEB)

    Rakhno, I.L.; Drozhdin, A.I.; Mokhov, N.V.; Sidorov, V.I.; Tropin, I.S.; /Fermilab

    2012-05-14

    A fast vertical 1.08-m long kicker (notcher) located in the Fermilab Booster Long-05 straight section is currently used to remove 3 out of 84 circulating bunches after injection to generate an abort gap. With the maximum magnetic field of 72.5 Gauss, it removes only 87% of the 3-bunch intensity at 400 MeV, with 75% loss on pole tips of the focusing Booster magnets, 11% on the Long-06 collimators, and 1% in the rest of the ring. We propose to improve the notching efficiency and reduce beam loss in the Booster by using three horizontal kickers in the Long-12 section. STRUCT calculations show that using horizontal notchers, one can remove up to 96% of the 3-bunch intensity at 400-700 MeV, directing 95% of it to a new beam dump at the Long-13 section. This fully decouples notching and collimation. The beam dump absorbs most of the impinging proton energy in its jaws. The latter are encapsulated into an appropriate radiation shielding that reduces impact on the machine components, personnel and environment to the tolerable levels. MARS simulations show that corresponding prompt and residual radiation levels can be reduced ten times compared to the current ones.

  13. Experimental Investigation on a Radiation Beam Steering Function of a Plate Waveguide Sensor

    International Nuclear Information System (INIS)

    Liquid sodium is used as the coolant in a Sodium Fast Reactor (SFR). As the liquid sodium is opaque to light, a conventional visual inspection can not be used for performing an inservice inspection of the internal structures under a sodium level. An ultrasonic wave should be applied for an under-sodium visual inspection of the reactor internals. Under-sodium ultrasonic sensors have been widely developed for a visual inspection of the reactor core and the internal components of SFR. Immersion sensors and waveguide sensors have been applied to the under-sodium visualization. The immersion sensor has a precise imaging capability, but may have high temperature restrictions and an uncertain life. The waveguide sensor has the advantages of a long lifetime and stable application. Recently a new plate-type waveguide sensor has been developed for an under-sodium visual inspection. And a new technique is presented which is capable of steering an ultrasonic beam of a waveguide sensor without a mechanical movement of the sensor assembly. The steering function of the ultrasonic radiation beam can be achieved by a frequency tuning method of the excitation pulse in the dispersive low frequency range of the A0 plate wave. In this study, experimental verifications of an ultrasonic radiation beam propagation of a plate waveguide sensor are performed

  14. Investigation of the clinical potential of scattering foil free electron beams

    International Nuclear Information System (INIS)

    Electron beam therapy has been an important radiation therapy modality for many decades. Studies have been conducted recently for more efficient and advanced delivery of electron beam radiation therapy. X-ray contamination is a common problem that exists with all of the advanced electron beam therapy techniques such as Bolus Electron conformal therapy, segmented electron conformal therapy, and modulated electron arc therapy. X-ray contamination could add some limitations to the advancement and clinical utility of those electron modalities. It was previously shown in the literature that the scattering foil is one of the major accelerator parts contributing to the generation of bremsstrahlung photons. Thus, in this work we investigate the dosimetric characteristics of scattering foil free (SFF) electron beams and the feasibility of using those beams for breast cancer boosts. The SFF electron beams were modeled and simulated using the Monte Carlo method. CT scans of six previously treated breast patients were used for the treatment plan generation utilizing our in-house Monte Carlo-based treatment planning system. Electron boost plans with conventional beams and the SFF beams were generated, respectively, for all patients. A significant reduction of the photon component was observed with the removal of the primary scattering foil for beam energies higher than 12 MeV. Flatness was greatly affected but the difference in flatness between conventional and SFF beams was much reduced for small cone sizes, which were often used clinically for breast boosts. It was found that the SFF electron beams could deliver high-quality dose distributions as conventional electron beams for boost treatments of the breast with an added advantage of a further reduced dose to the lung and the heart. (paper)

  15. Generation and modelling of megavoltage photon beams for contrast-enhanced radiation therapy

    Science.gov (United States)

    Robar, J. L.

    2006-11-01

    Contrast-enhanced radiation therapy (CERT) is a treatment approach involving the irradiation of tumours containing high atomic number (Z) contrast media, using low-quality x-ray beams. This work describes the experimental generation of x-ray beams using a linear accelerator with low-Z target materials (beryllium and aluminium), in order to produce photon energy spectra appropriate for CERT. Measurements were made to compare the experimental beams to conventional linear accelerator photon beams in terms of per cent depth dose. Monte Carlo simulation was used to model the generation of each beam, and models were validated against experimental measurement. Validated models were used to demonstrate changes in photon spectra as well as to quantify the variation of tumour dose enhancement with iodinated contrast medium concentration in a simulated tumour volume. Finally, the ratio of the linear attenuation coefficient for iodinated contrast medium relative to water was determined experimentally as a function of iodine concentration. Beams created with low-Z targets show significant changes in energy spectra compared to conventional beams. For the 4 MeV/Be beam, for example, 33% of photons have energies below 60 keV. Measurements and calculation show that both the linear attenuation coefficient ratio and dose enhancement factor (DEF) increase most rapidly at concentrations below 46 mg I ml-1. There is a significant dependence of DEF on electron energy and a lesser dependence on target material. The 4 MeV/Be beam is the most promising in terms of magnitude of DEF—for example, DEF values of 1.16 and 1.29 are obtained for concentrations of 20 mg I ml-1 and 50 mg I ml-1, respectively. DEF will increase or decrease, respectively, for shallower or deeper tumours at a rate of approximately 1.1% cm-1. In summary, we show that significant dose enhancement is possible by altering the linear accelerator target and filtration, but the magnitude is highly dependent on contrast

  16. Two-parametric model of electron beam in computational dosimetry for radiation processing

    Science.gov (United States)

    Lazurik, V. M.; Lazurik, V. T.; Popov, G.; Zimek, Z.

    2016-07-01

    Computer simulation of irradiation process of various materials with electron beam (EB) can be applied to correct and control the performances of radiation processing installations. Electron beam energy measurements methods are described in the international standards. The obtained results of measurements can be extended by implementation computational dosimetry. Authors have developed the computational method for determination of EB energy on the base of two-parametric fitting of semi-empirical model for the depth dose distribution initiated by mono-energetic electron beam. The analysis of number experiments show that described method can effectively consider random displacements arising from the use of aluminum wedge with a continuous strip of dosimetric film and minimize the magnitude uncertainty value of the electron energy evaluation, calculated from the experimental data. Two-parametric fitting method is proposed for determination of the electron beam model parameters. These model parameters are as follow: E0 - energy mono-energetic and mono-directional electron source, X0 - the thickness of the aluminum layer, located in front of irradiated object. That allows obtain baseline data related to the characteristic of the electron beam, which can be later on applied for computer modeling of the irradiation process. Model parameters which are defined in the international standards (like Ep- the most probably energy and Rp - practical range) can be linked with characteristics of two-parametric model (E0, X0), which allows to simulate the electron irradiation process. The obtained data from semi-empirical model were checked together with the set of experimental results. The proposed two-parametric model for electron beam energy evaluation and estimation of accuracy for computational dosimetry methods on the base of developed model are discussed.

  17. A nested partitions framework for beam angle optimization in intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Coupling beam angle optimization with dose optimization in intensity-modulated radiation therapy (IMRT) increases the size and complexity of an already large-scale combinatorial optimization problem. We have developed a novel algorithm, nested partitions (NP), that is capable of finding suitable beam angle sets by guiding the dose optimization process. NP is a metaheuristic that is flexible enough to guide the search of a heuristic or deterministic dose optimization algorithm. The NP method adaptively samples from the entire feasible region, or search space, and coordinates the sampling effort with a systematic partitioning of the feasible region at successive iterations, concentrating the search in promising subsets. We used a 'warm-start' approach by initiating NP with beam angle samples derived from an integer programming (IP) model. In this study, we describe our implementation of the NP framework with a commercial optimization algorithm. We compared the NP framework with equi-spaced beam angle selection, the IP method, greedy heuristic and random sampling heuristic methods. The results of the NP approach were evaluated using two clinical cases (head and neck and whole pelvis) involving the primary tumor and nodal volumes. Our results show that NP produces better quality solutions than the alternative considered methods

  18. Chromium Waste Treatment from Leather Manufacture Using Electron Beam Radiation Technic

    International Nuclear Information System (INIS)

    Leather manufacture chromium waste treatment using chemical methods have an essential disadvantage, because of the production of the secondary contamination of wastes and separated sediments used by reagents. Therefore, a new technique is needed to solve this problem. The aim of the research to learn the advantages of electron beam radiation for chromium waste treatment. Water radiolysis can be produced by the interaction between electron beam and water or liquid substances. This phenomenon produces many reducing agents and ions that could reduce chromium concentrations in the liquid waste. Ethyl alcohol as a scavenger was added in the waste samples, then the pH of varied from 1, 4, 8 to 12, then were irradiated. Irradiation were done by Electron Beam Machine with dose 15, 25, and 35 kGy. After irradiation, chromium concentration in the samples were analyzed by AAS and UV-vis spectrophotometer. The results had shown that chromium could be reduced by high dose electron beam. The optimum reduction of chromium was achieved at liquid waste pH 8 and irradiation dose 35 kGy. (author)

  19. Implementation of a system for external audits beam radiation therapy in terms of reference no

    International Nuclear Information System (INIS)

    This paper presents our experience in implementing a external audit system for radiotherapy beam in no reference conditions with the use of CIRS and a summary of the measurements with him made.This paper presents our experience in implementing a external audit system for radiotherapy beam in no reference conditions with the use of CIRS and a summary of the measurements with him made. Centers were audited with external beam high-energy Co-60, 6 MV and 15 MV and were considered 4 treatment planning systems (TPS): AMEPLAN, Theraplan Plus, Precise Plan and MIRS to calculate doses prescribed in each test case. All measurements were acquired by the audit team using the anthropomorphic phantom CIRS, Semiflex chamber PTW 31010 and PTW electrometer STATES. The implementation and development of the external audits of beams radiotherapy in terms of 'no reference' has brought an improvement in both clinical aspects of treatment and the radiation safety and the quality control, has given us greater confidence and for this reason we believe has become essential. (Author)

  20. Direct-aperture optimization applied to selection of beam orientations in intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Direct-aperture optimization (DAO) was applied to iterative beam-orientation selection in intensity-modulated radiation therapy (IMRT), so as to ensure a realistic segmental treatment plan at each iteration. Nested optimization engines dealt separately with gantry angles, couch angles, collimator angles, segment shapes, segment weights and wedge angles. Each optimization engine performed a random search with successively narrowing step sizes. For optimization of segment shapes, the filtered backprojection (FBP) method was first used to determine desired fluence, the fluence map was segmented, and then constrained direct-aperture optimization was used thereafter. Segment shapes were fully optimized when a beam angle was perturbed, and minimally re-optimized otherwise. The algorithm was compared with a previously reported method using FBP alone at each orientation iteration. An example case consisting of a cylindrical phantom with a hemi-annular planning target volume (PTV) showed that for three-field plans, the method performed better than when using FBP alone, but for five or more fields, neither method provided much benefit over equally spaced beams. For a prostate case, improved bladder sparing was achieved through the use of the new algorithm. A plan for partial scalp treatment showed slightly improved PTV coverage and lower irradiated volume of brain with the new method compared to FBP alone. It is concluded that, although the method is computationally intensive and not suitable for searching large unconstrained regions of beam space, it can be used effectively in conjunction with prior class solutions to provide individually optimized IMRT treatment plans

  1. A nested partitions framework for beam angle optimization in intensity-modulated radiation therapy

    Science.gov (United States)

    D'Souza, Warren D.; Zhang, Hao H.; Nazareth, Daryl P.; Shi, Leyuan; Meyer, Robert R.

    2008-06-01

    Coupling beam angle optimization with dose optimization in intensity-modulated radiation therapy (IMRT) increases the size and complexity of an already large-scale combinatorial optimization problem. We have developed a novel algorithm, nested partitions (NP), that is capable of finding suitable beam angle sets by guiding the dose optimization process. NP is a metaheuristic that is flexible enough to guide the search of a heuristic or deterministic dose optimization algorithm. The NP method adaptively samples from the entire feasible region, or search space, and coordinates the sampling effort with a systematic partitioning of the feasible region at successive iterations, concentrating the search in promising subsets. We used a 'warm-start' approach by initiating NP with beam angle samples derived from an integer programming (IP) model. In this study, we describe our implementation of the NP framework with a commercial optimization algorithm. We compared the NP framework with equi-spaced beam angle selection, the IP method, greedy heuristic and random sampling heuristic methods. The results of the NP approach were evaluated using two clinical cases (head and neck and whole pelvis) involving the primary tumor and nodal volumes. Our results show that NP produces better quality solutions than the alternative considered methods.

  2. Improving precision and safety in the use of beam modifying devices in radiation therapy

    International Nuclear Information System (INIS)

    Reliable and safe implementation of beam modifying devices such as wedges and block trays requires careful design and construction. Inappropriate design may pose problems ranging from user-hostile operation to hard-to-track, but significant variations in actual position in a beam. This may cause variation in actual wedge output factors, or variation in the position of a block tray. In case of simple mechanical failure or personnel mistake, design related mechanical conditions may result in injury to either a patient or a staff member. This paper is based on experience with linear accelerators from one manufacturer, but similar conditions are likely to exist with other radiation machines. A simple technical modification is offered which improves both accuracy and reproducibility in the placement of wedge-type filters. For our machines the solution also provides improved safety in the use of both wedge trays and block trays

  3. Inclined-incidence quasi-Fresnel lens for prefocusing of synchrotron radiation x-ray beams

    International Nuclear Information System (INIS)

    An inclined-incidence quasi-Fresnel lens made of acrylic resin has been developed for prefocusing in synchrotron radiation x-ray beamlines. By inclining the lens, the grating aspect ratio is large enough for x-ray use. As it operates in transmission mode with negligible beam deflection and offset, little additional equipment is needed to introduce it into existing beamlines. It is fabricated by sheet-press forming, enabling inexpensive mass production. The prototype was able to focus a 730-μm-wide beam to a width of 80 μm with a photon flux density gain of 5.6 at an x-ray energy of 10 keV.

  4. Calculation and measurement of build-up factors in divergent gamma radiation beams

    International Nuclear Information System (INIS)

    The methods and the results are presented of the calculation and experimental determination of build-up factors in a broad divergent gamma radiation beam passing through a planar layer of material. A computer program based on the Monte Carlo method is described as is the experimental configuration used. The dependence was determined of the build-up factor on the beam collimation angle, the distance of the source and the distance of the detector from the layer to be radiographed. No dependence was confirmed on the detector diameter. The measurements conducted confirmed agreement with the calculated results within the maximum error limit of +-10%. The results of calculation and measurements are shown in graphs

  5. Particle in cell simulation of laser-accelerated proton beams for radiation therapy

    International Nuclear Information System (INIS)

    In this article we present the results of particle in cell (PIC) simulations of laser plasma interaction for proton acceleration for radiation therapy treatments. We show that under optimal interaction conditions protons can be accelerated up to relativistic energies of 300 MeV by a petawatt laser field. The proton acceleration is due to the dragging Coulomb force arising from charge separation induced by the ponderomotive pressure (light pressure) of high-intensity laser. The proton energy and phase space distribution functions obtained from the PIC simulations are used in the calculations of dose distributions using the GEANT Monte Carlo simulation code. Because of the broad energy and angular spectra of the protons, a compact particle selection and beam collimation system will be needed to generate small beams of polyenergetic protons for intensity modulated proton therapy

  6. Hydrogel wound dressing preparation at the laboratory scale by using electron beam and gamma radiation

    International Nuclear Information System (INIS)

    The present work describes the preparation of hydrogel based on cross-linked networks of poly (N-vinylpirrolidone), PVP, with polyethyleneglicol and agar with 90% water and PVP nancomposites with a synthetic nanoclay, Laponite XLG, for use as burn dressings. These systems were obtained in two ways: using gamma Co-60 and electron beam radiation. The gelation obtained dose was Dg= 1.72 kGy. The elastic modulus of hydrogel was independent of the method of irradiation. It was 0.39 MPa for the hydrogel irradiated with gamma Co-60 and 0.38 MPa for electron beam irradiation. The elastic modulus of the nanocomposite membrane was 1.25 MPa, three times higher. These results indicate that the PVP/Laponite XLG nanocomposite hydrogel membrane is the best choice for wound dressing applications due to its high water sorption capacity and its superior mechanical properties.

  7. Inclined-incidence quasi-Fresnel lens for prefocusing of synchrotron radiation x-ray beams

    Science.gov (United States)

    Kagoshima, Yasushi; Takano, Hidekazu; Takeda, Shingo

    2012-10-01

    An inclined-incidence quasi-Fresnel lens made of acrylic resin has been developed for prefocusing in synchrotron radiation x-ray beamlines. By inclining the lens, the grating aspect ratio is large enough for x-ray use. As it operates in transmission mode with negligible beam deflection and offset, little additional equipment is needed to introduce it into existing beamlines. It is fabricated by sheet-press forming, enabling inexpensive mass production. The prototype was able to focus a 730-μm-wide beam to a width of 80 μm with a photon flux density gain of 5.6 at an x-ray energy of 10 keV.

  8. Mission critical operation archiving system using a database for synchrotron radiation beam lines at the Photon Factory

    International Nuclear Information System (INIS)

    The mission critical operation archiving system has been designed and built using the Oracle database for the twenty-two synchrotron radiation beam lines at the 2.5 GeV positron storage ring at the Photon Factory, where X-ray/VUV synchrotron radiation experiments are simultaneously carried out. When any one of beam lines is malfunctioning, neither injecting the 2.5 GeV beam into the storage ring nor operation of the ring is allowed due to the radiation safety reason. The system is designed for critical operation of the synchrotron radiation beam lines to provide a quick recovery from a failure, allowing a long term operation. The system has real-time capability to automatically store the database with all possible operational events of all vacuum valves/shutters and safety interlock signals, and all static operational data, including the pressures of the beam lines and the storage ring, and related operational data which represent the physical behaviors of the beam lines. By retrieving any combination of operational data, the system allows to reproduce the physical behaviors that have occurred in the beam lines. The total number of items to be inspected by the system is over 40 million in order to obtain a correlation between the faulty component and other physical components that suggests the cause of the failure. With the aid of the system, the operator at the control room can easily determine the faulty component, and recover the accelerator component. (author)

  9. Study of the properties of inverted liquid sugar processed with gamma radiation and electron beam

    International Nuclear Information System (INIS)

    Brazil occupies position of prominence in the sugar market and high consumption of this ingredient in the liquid form, in special for the beverages and food industries. The liquid sugar presents advantages in relation to the bulk granulated system such as easiness of the handling and dosage, reduced space for the storage, reduction of the losses, costs and hand of workmanship, improvement of the sanitizing and great possible variation in the ratios of different mixtures of sugars. The inverted liquid sugar is a solution of sucrose, glucose and fructose in water. This ingredient receives this name because during its production it has an inversion of the optic power of rotation of the solution. In the productive process of the inverted sugar some points occur that can generate contamination by microorganisms, so its become important the development of techniques that propitiate the efficient sanitizing of this raw material. This work aims at to consider two alternative techniques of microbiologic control: gamma radiation with source of cobalto-60 and radiation with electron beam. The study was lead in the doses of 5, 10, 20, 30 and 50 kGy. Concentration of sucrose presented in syrup decreased with the radiation indicating the scission of glycosidic linkage in addition with the glucose and fructose formation, generating the increase in solids soluble. The acid compounds formation occurred, confirmed by the reduction of pH, that it was proportional with the increase of the radiation dose. The biggest doses had provoked change of color in the syrup by the long molecular chain polymers formation. Viscosity in the samples processed by gamma radiation increased in relation to the control, indicating the prevalence of polymerization of molecules, whereas in the radiation with electron beam the polymerization was only observed in the sample that received the dose of 50 kGy, In the sensorial analysis, the judges had pointed significant difference (5%) in the flavor among

  10. A method of determining narrow energy spread electron beams from a laser plasma wakefield accelerator using undulator radiation

    International Nuclear Information System (INIS)

    In this paper a new method of determining the energy spread of a relativistic electron beam from a laser-driven plasma wakefield accelerator by measuring radiation from an undulator is presented. This could be used to determine the beam characteristics of multi-GeV accelerators where conventional spectrometers are very large and cumbersome. Simultaneous measurement of the energy spectra of electrons from the wakefield accelerator in the 55-70 MeV range and the radiation spectra in the wavelength range of 700-900 nm of synchrotron radiation emitted from a 50 period undulator confirm a narrow energy spread for electrons accelerated over the dephasing distance where beam loading leads to energy compression. Measured energy spreads of less than 1% indicates the potential of using a wakefield accelerator as a driver of future compact and brilliant ultrashort pulse synchrotron sources and free-electron lasers that require high peak brightness beams.

  11. Measurement of therapeutic photon beams-induced Cerenkov radiation generated in PMMA- and PS-based plastic optical fibers

    Science.gov (United States)

    Lee, Bongsoo; Shin, Sang Hun; Yoo, Wook Jae; Jang, Kyoung Won

    2016-07-01

    In this study, we characterized Cerenkov radiation generated in polystyrene (PS)- and polymethyl methacrylate (PMMA)-based plastic optical fibers (POFs) to select an adequate optical fiber for producing Cerenkov radiation. To determine the relationship between the absorbed dose and the intensity of Cerenkov radiation, we calculated the energy depositions of photon beams and fluxes of electrons inducing Cerenkov radiation using the Monte Carlo N-Particle eXtended code. Also, intensities of Cerenkov radiation generated in PS- and PMMA-based POFs were measured as functions of dose rate and monitor unit. At last, therapeutic photon beams-induced Cerenkov radiation in PS- and PMMA-based POFs was measured according to depths of solid water phantom.

  12. Effect of Photon Beam Energy, Gold Nanoparticle Size and Concentration on the Dose Enhancement in Radiation Therapy

    Directory of Open Access Journals (Sweden)

    Nahideh Gharehaghaji

    2013-02-01

    Full Text Available Introduction: Gold nanoparticles have been used as radiation dose enhancing materials in recent investigations. In the current study, dose enhancement effect of gold nanoparticles on tumor cells was evaluated using Monte Carlo (MC simulation. Methods: We used MCNPX code for MC modeling in the current study. A water phantom and a tumor region with a size of 1×1×1 cm3 loaded with gold nanoparticles were simulated. The macroscopic dose enhancement factor was calculated for gold nanoparticles with sizes of 30, 50, and 100 nm. Also, we simulated different photon beams including mono-energetic beams (50-120 keV, a Cobalt-60 beam, 6 & 18 MV photon beams of a conventional linear accelerator. Results: We found a dose enhancement factor (DEF of from 1.4 to 3.7 for monoenergetic kilovoltage beams, while the DEFs for megavoltage beams were negligible and less than 3% for all GNP sizes and concentrations. The optimum energy for higher DEF was found to be the 90 keV monoenergetic beam. The effect of GNP size was not considerable, but the GNP concentration had a substantial impact on achieved DEF in GNP-based radiation therapy. Conclusion: The results were in close agreement with some previous studies considering the effect of photon energy and GNP concentration on observed DEF. Application of GNP-based radiation therapy using kilovoltage beams is recommended.

  13. Enhancement of terahertz radiation power from a prebunched electron beam using helical wiggler and ion-channel guiding

    Science.gov (United States)

    Hasanbeigi, A.; Mehdian, H.; Gomar, P.

    2015-12-01

    The generation of coherent Terahertz (THz) radiation from the interaction of a bunched relativistic electron beam with helical wiggler pumped is studied on a basis of fluid model. The relativistic electron beam, modulated by two laser beams, propagates through a helical wiggler with ion-channel guiding. Numerical results show that the Terahertz power increases monotonically with the increasing ion-channel frequency up to a critical point corresponding to the increase in the transverse velocity as the resonance (at ω i ≅ β | | ) is approached. The maximum THz power increases with the increasing ion-channel density, the axial velocity, and the radius of the injected beam.

  14. Noncoplanar Beam Angle Class Solutions to Replace Time-Consuming Patient-Specific Beam Angle Optimization in Robotic Prostate Stereotactic Body Radiation Therapy

    International Nuclear Information System (INIS)

    Purpose: To investigate development of a recipe for the creation of a beam angle class solution (CS) for noncoplanar prostate stereotactic body radiation therapy to replace time-consuming individualized beam angle selection (iBAS) without significant loss in plan quality, using the in-house “Erasmus-iCycle” optimizer for fully automated beam profile optimization and iBAS. Methods and Materials: For 30 patients, Erasmus-iCycle was first used to generate 15-, 20-, and 25-beam iBAS plans for a CyberKnife equipped with a multileaf collimator. With these plans, 6 recipes for creation of beam angle CSs were investigated. Plans of 10 patients were used to create CSs based on the recipes, and the other 20 to independently test them. For these tests, Erasmus-iCycle was also used to generate intensity modulated radiation therapy plans for the fixed CS beam setups. Results: Of the tested recipes for CS creation, only 1 resulted in 15-, 20-, and 25-beam noncoplanar CSs without plan deterioration compared with iBAS. For the patient group, mean differences in rectum D1cc, V60GyEq, V40GyEq, and Dmean between 25-beam CS plans and 25-beam plans generated with iBAS were 0.2 ± 0.4 Gy, 0.1% ± 0.2%, 0.2% ± 0.3%, and 0.1 ± 0.2 Gy, respectively. Differences between 15- and 20-beam CS and iBAS plans were also negligible. Plan quality for CS plans relative to iBAS plans was also preserved when narrower planning target volume margins were arranged and when planning target volume dose inhomogeneity was decreased. Using a CS instead of iBAS reduced the computation time by a factor of 14 to 25, mainly depending on beam number, without loss in plan quality. Conclusions: A recipe for creation of robust beam angle CSs for robotic prostate stereotactic body radiation therapy has been developed. Compared with iBAS, computation times decreased by a factor 14 to 25. The use of a CS may avoid long planning times without losses in plan quality

  15. Noncoplanar Beam Angle Class Solutions to Replace Time-Consuming Patient-Specific Beam Angle Optimization in Robotic Prostate Stereotactic Body Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Linda, E-mail: l.rossi@erasmusmc.nl; Breedveld, Sebastiaan; Aluwini, Shafak; Heijmen, Ben

    2015-07-15

    Purpose: To investigate development of a recipe for the creation of a beam angle class solution (CS) for noncoplanar prostate stereotactic body radiation therapy to replace time-consuming individualized beam angle selection (iBAS) without significant loss in plan quality, using the in-house “Erasmus-iCycle” optimizer for fully automated beam profile optimization and iBAS. Methods and Materials: For 30 patients, Erasmus-iCycle was first used to generate 15-, 20-, and 25-beam iBAS plans for a CyberKnife equipped with a multileaf collimator. With these plans, 6 recipes for creation of beam angle CSs were investigated. Plans of 10 patients were used to create CSs based on the recipes, and the other 20 to independently test them. For these tests, Erasmus-iCycle was also used to generate intensity modulated radiation therapy plans for the fixed CS beam setups. Results: Of the tested recipes for CS creation, only 1 resulted in 15-, 20-, and 25-beam noncoplanar CSs without plan deterioration compared with iBAS. For the patient group, mean differences in rectum D{sub 1cc}, V{sub 60GyEq}, V{sub 40GyEq}, and D{sub mean} between 25-beam CS plans and 25-beam plans generated with iBAS were 0.2 ± 0.4 Gy, 0.1% ± 0.2%, 0.2% ± 0.3%, and 0.1 ± 0.2 Gy, respectively. Differences between 15- and 20-beam CS and iBAS plans were also negligible. Plan quality for CS plans relative to iBAS plans was also preserved when narrower planning target volume margins were arranged and when planning target volume dose inhomogeneity was decreased. Using a CS instead of iBAS reduced the computation time by a factor of 14 to 25, mainly depending on beam number, without loss in plan quality. Conclusions: A recipe for creation of robust beam angle CSs for robotic prostate stereotactic body radiation therapy has been developed. Compared with iBAS, computation times decreased by a factor 14 to 25. The use of a CS may avoid long planning times without losses in plan quality.

  16. Tailoring of Highly Intense THz Radiation Through High Brightness Electron Beams Longitudinal Manipulation

    Directory of Open Access Journals (Sweden)

    Flavio Giorgianni

    2016-02-01

    Full Text Available The ultra-short electron beams, produced through the velocity bunching compression technique at the SPARC_LAB test Facility (Frascati, Italy, are used to produce Coherent Transition Radiation in the terahertz (THz range. This paper reports on the main features of this THz source, which have a spectral coverage up to 5 THz, a pulse duration down to 100 fs, and an energy per pulse on the order of tens of μJ. These figures of merits open the possibility to apply this source for nonlinear and THz pump-probe experiments in Solid-State Physics and material science.

  17. Quality control beam of radiation through imaging system using a flat panel (ILD)

    International Nuclear Information System (INIS)

    The daily quality checks of the accelerator include, among others, checks of the daily calibration, symmetry and uniformity of the radiation beam. Usually verification systems daily are used for this purpose, which employ arrays of detectors of solid-state or ionization chambers. This paper intends to carry out the control of quality through the irradiation of a number of fields in the portal imaging system and its subsequent analysis in software's own creation, as well as the comparison of results with the daily verification system. (Author)

  18. Microwave radiation power of relativistic electron beam with virtual cathode in the external magnetic field

    Science.gov (United States)

    Kurkin, S. A.; Hramov, A. E.; Koronovskii, A. A.

    2013-07-01

    The study of the output power of the electromagnetic radiation of the relativistic electron beam (REB) with virtual cathode in the presence of external magnetic field has been found out. The typical dependencies of the output microwave power of the vircator versus external magnetic field have been analyzed by means of 3D electromagnetic simulation. It has been shown that the power of vircator demonstrates several maxima with external magnetic field growth. The characteristic features of the power behavior are determined by the conditions of the virtual cathode formation in the presence of the external transversal magnetic field and the REB self-magnetic fields.

  19. Microwave radiation power of relativistic electron beam with virtual cathode in the external magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Kurkin, S. A.; Hramov, A. E.; Koronovskii, A. A. [Saratov State University, Astrakhanskaja 83, Saratov 410012 (Russian Federation); Saratov State Technical University, Politechnicheskaja 77, Saratov 410028 (Russian Federation)

    2013-07-22

    The study of the output power of the electromagnetic radiation of the relativistic electron beam (REB) with virtual cathode in the presence of external magnetic field has been found out. The typical dependencies of the output microwave power of the vircator versus external magnetic field have been analyzed by means of 3D electromagnetic simulation. It has been shown that the power of vircator demonstrates several maxima with external magnetic field growth. The characteristic features of the power behavior are determined by the conditions of the virtual cathode formation in the presence of the external transversal magnetic field and the REB self-magnetic fields.

  20. Detection of Cherenkov radiation: the inverse problem to generation of nondiffracting beams

    Czech Academy of Sciences Publication Activity Database

    Miler, Miroslav; Pala, Jan

    2003-01-01

    Roč. 33, 2-3 (2003), s. 307-313. ISSN 0078-5466. [Polish-Czech-Slovak Optica l Conference on Wave and Quantum Aspects of Contemporary Optics PCS /13./. Krzyzowa, 09.09.2002-13.09.2002] R&D Projects: GA ČR GA102/01/0429 Institutional research plan: CEZ:AV0Z2067918 Keywords : Cherenkov radiation * holographic optica l elements * laser beams * diffraction Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.221, year: 2003

  1. Multicomponent measurements of the Jefferson Lab energy recovery linac electron beam using optical transition and diffraction radiation

    Science.gov (United States)

    Holloway, M. A.; Fiorito, R. B.; Shkvarunets, A. G.; O'Shea, P. G.; Benson, S. V.; Douglas, D.; Evtushenko, P.; Jordan, K.

    2008-08-01

    High brightness electron accelerators, such as energy recovery linacs (ERL), often have complex particle distributions that can create difficulties in beam transport as well as matching to devices such as wigglers used to generate radiation from the beam. Optical transition radiation (OTR), OTR interferometry (OTRI), and optical diffraction-transition radiation interferometry (ODTRI) have proven to be effective tools for diagnosing both the spatial and angular distributions of charged particle beams. OTRI and ODTRI have been used to measure rms divergences, and optical transverse phase space mapping has been demonstrated using OTRI. In this work we present the results of diagnostic experiments using OTR and optical diffraction radiation conducted at the Jefferson Laboratory’s 115 MeV ERL which show the presence of two separate components within the beam’s spatial and angular distributions. By assuming a correlation between the spatial and angular features, we estimate an rms emittance value for each of the two components.

  2. Influence of nuclear radiation and laser beams on optical fibers and components

    Directory of Open Access Journals (Sweden)

    Pantelić Slađana N.

    2011-01-01

    Full Text Available The influence of nuclear radiation and particles has been the object of investigation for a long time. For new materials and systems the research should be continued. Human activities in various environments, including space, call for more detailed research. The role of fibers in contemporary communications, medicine, and industry increases. Fibers, their connections and fused optics components have one type of tasks - the transmission of information and power. The other type of tasks is reserved for fiber lasers: quantum generators and amplifiers. The third type of tasks is for fiber sensors, including high energy nuclear physics. In this paper we present some chosen topics in the mentioned areas as well as our experiments with nuclear radiation and laser beams to fiber and bulk materials of various nature (glass, polymer, metallic, etc..

  3. Present status of study on development of materials resistant to radiation and beam impact

    International Nuclear Information System (INIS)

    Pulsed spallation neutron sources for the materials structure science are severely influenced by beam impact and radiation damage. We have developed the materials strong to these influence since 2004. In this paper, recent topics are described concerning the development of intergranular corrosion (IGC)-resistant austenitic stainless steel for target vessel and window, radiation-resistant ultra-fine grained tungsten materials (W-TiC) for a solid target, CrN film on a tungsten target by means of a molten-salt method, surface treatment of stainless steel for pitting damage in mercury target. Bubble behavior at the interface of mercury and window glass was also observed to clarify the phenomenon of the pitting damage

  4. Preparation and characterization of polyethylene glycol diacrylate microgels using electron beam radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hamzah, Mohd Yusof [Makmal Nanoteknologi, Bahagian Teknologi Sinaran (Malaysia); Isa, Naurah Mat; Napia, Liyana M. Ali [ALURTRON, Bahagian Kemudahan Iradiasi, Malaysian Nuclear Agency, 43000, Kajang, Selangor (Malaysia)

    2014-02-12

    The use of microemulsion in the development of nanosized gels based on polyethylene glycol diacrylate (PEGDA) is demonstrated. PEGDA was solubilized in n-heptane with use of sodium docusate (AOT) at 0.15M concentration to form reverse micelles. These micelles were than irradiated at 5, 10, 15, 20 and 25 kGy using electron beam (EB) to crosslink the entrapped polymer in the micelles. Ionizing radiation was imparted to the emulsions to generate crosslinking reaction in the micelles formed. The nanosized gels were evaluated in terms of particle diameter using dynamic light scattering (DLS) and the images of the nanosized gels were studied using transmission electron microscopy (TEM). Results show that the size and shape of the particles are influenced by concentration of PEGDA and radiation dose. This study showed that this method can be utilized to produce nanosized gels.

  5. Efficacy and toxicity of conventionally fractionated pelvic radiation with a hypo fractionated simultaneous versus conventionally fractionated sequential boost for patients with high-risk prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, Andrew M.; Jacob, Rojymon; Dobelbower, Michael C.; Kim, Robert Y.; Fiveash, John B. [Univ. of Alabama at Birmingham, Dept. of Radiation Oncology, Birmingham, Alabama (United States)], e-mail: friezu@uab.edu

    2013-08-15

    Purpose: To determine if high-risk prostate cancer responds differently to hypo fractionation. Material and methods: One hundred and fifty-seven men with NCCN high-risk (T3, PSA 20, or Gleason 8) clinically localized prostate cancer treated between 1998 and 2010 met the inclusion criteria for the analysis. Eighty-two were treated with conventional WPRT with a conventionally fractionated sequential boost to the prostate (cRT), with the prostate receiving 75-77 Gy in 1.8 - 2.0 Gy fractions. Seventy-five were treated with pelvic IMRT with a hypo fractionated simultaneous boost to the prostate (hRT), with the prostate receiving 70 Gy in 2.5 Gy fractions. The dose to the pelvic lymph nodes was 45 Gy in the cRT group and 50.4 Gy in the hRT group, both at 1.8 Gy per fraction. Ninety-two percent received neoadjuvant hormonal ablation therapy, typically beginning two months prior to the start of RT. Results: Median follow-up was 6.5 years for men receiving cRT and 3.7 years for those receiving hRT. The actuarial rate of biochemical control at four years was 88% for cRT and 94% for hRT (p=0.82). The rates of early rectal and urinary grade {>=}2 toxicities were 35% (29 of 82) and 49% (40 of 82) for the cRT group and 36% (27 of 75) and 44% (33 of 75) for the hRT group. The actuarial rate of late grade 2 rectal toxicity at four years was 25% for the cRT group and 13% for the hRT group (p=0.037). The rate of late grade 3 rectal complications was 4% (3 of 82) for patients receiving cRT and 1% (1 of 75) for patients receiving hRT. Conclusion: Initial follow-up indicates equivalent biochemical control between regimens. Patients receiving hRT experienced fewer late rectal complications.

  6. Stereotactic body radiation therapy for liver tumours using flattening filter free beam: dosimetric and technical considerations

    International Nuclear Information System (INIS)

    To report the initial institute experience in terms of dosimetric and technical aspects in stereotactic body radiation therapy (SBRT) delivered using flattening filter free (FFF) beam in patients with liver lesions. From October 2010 to September 2011, 55 consecutive patients with 73 primary or metastatic hepatic lesions were treated with SBRT on TrueBeam using FFF beam and RapidArc technique. Clinical target volume (CTV) was defined on multi-phase CT scans, PET/CT, MRI, and 4D-CT. Dose prescription was 75 Gy in 3 fractions to planning target volume (PTV). Constraints for organs at risk were: 700 cc of liver free from the 15 Gy isodose, Dmax < 21 Gy for stomach and duodenum, Dmax < 30 Gy for heart, D0.1 cc < 18 Gy for spinal cord, V15 Gy < 35% for kidneys. The dose was downscaled in cases of not full achievement of dose constraints. Daily cone beam CT (CBCT) was performed. Forty-three patients with a single lesion, nine with two lesions and three with three lesions were treated with this protocol. Target and organs at risk objectives were met for all patients. Mean delivery time was 2.8 ± 1.0 min. Pre-treatment plan verification resulted in a Gamma Agreement Index of 98.6 ± 0.8%. Mean on-line co-registration shift of the daily CBCT to the simulation CT were: -0.08, 0.05 and -0.02 cm with standard deviations of 0.33, 0.39 and 0.55 cm in, vertical, longitudinal and lateral directions respectively. SBRT for liver targets delivered by means of FFF resulted to be feasible with short beam on time

  7. High-Dose-Rate Brachytherapy Boost for Prostate Cancer: Comparison of Two Different Fractionation Schemes

    International Nuclear Information System (INIS)

    Purpose: This is a retrospective study comparing our experience with high-dose-rate (HDR) brachytherapy boost for prostate cancer, using two different fractionation schemes, 600 cGy × 3 fractions (patient group 1) and 950 cGy × 2 fractions (patient group 2). Methods and Materials: A total of 165 patients were treated for prostate cancer using external beam radiation therapy up to a dose of 45 Gy, followed by an HDR brachytherapy prostate radiation boost. Between July 1997 and Nov 1999, 64 patients were treated with an HDR boost of 600 cGy × 3 fractions; and between June 2000 and Nov 2005, 101 patients were treated with an HDR boost of 950 cGy × 2 fractions. All but 9 patients had at least one of the following risk features: pretreatment prostate-specific antigen (PSA) level >10, a Gleason score ≥7, and/or clinical stage T3 disease. Results: Median follow-up was 105 months for group 1 and 43 months for group 2. Patients in group 2 had a greater number of high-risk features than group 1 (p = 0.02). Adjusted for comparable follow-up, there was no difference in biochemical no-evidence-of-disease (bNED) rate between the two fractionation scheme approaches, with 5-year Kaplan-Meier estimates of 93.5% in group 1 and 87.3% in group 2 (p = 0.19). The 5-year estimates of progression-free survival were 86% for group 1 and 83% for group 2 (p = 0.53). Among high-risk patients, there were no differences in bNED or PFS rate due to fractionation. Conclusions: Results were excellent for both groups. Adjusted for comparable follow-up, no differences were found between groups.

  8. Absolute power scaling measurements of Electromagnetic radiation at 2ω /sub uh/ generated by steady state colliding electron beams

    International Nuclear Information System (INIS)

    Space physics data indicate Electromagnetic (EM) emission correlated with the existence of electron beams in solar and planetary sources. The EM power is too large to be produced by linear plasma production mechanisms, suggesting that non-linear beam processes can coherently, enhance the generation of EM radiation. Steady state counterstreaming electron beams are produced in a triple plasma device, where they collide in a filament discharge target plasma. Neutral pressure is low (5 x 10-5 Torr), with background target density, n /sub e/ less than or equal to 1010 cm-3 and electron temperature T /sub e/ less than or equal to 4 eV . Beams are grid extracted from sources and collimated with a small axial magnetic field (B /sub o/ less than or equal to 10 Gauss). Beam density is n /sub b/ less than or equal to 108 cm-3 and beam energy is E /sub b/ < 150 eV. Plasma ions with varying masses such as He+, Ar+, Xe+ are used. Diagnostics are carried out with electrostatic probes and absolutely calibrated single turn Faraday shielded loop antennae. When counterstreaming electron beams are allowed to collide in the target, steady state electrostatic and electromagnetic disturbances are observed respectively at the upper hybrid frequency and the first harmonic. The colliding beam EM radiation power is seen to be greatly enhanced over that of the single beam case

  9. Angular dependence of OSL commercial detectors in standard beta radiation beams

    International Nuclear Information System (INIS)

    Full text: Optical stimulated luminescence (OSL) is a very successful dosimetry technique, in particular using the Al2O3:C crystals as dosimeter. This detector has become the main OSL material as a personal dosimeter. Commercial dosimeters of Al2O3:C have been developed and tested; however, most of the tests have been performed with gamma beams. Beta radiation dosimetry might be performed with Al2O3:C detectors, if the crystals are sufficient thin to avoid the radiation attenuation. The dosimeter thickness is also important to allow a satisfactory accuracy of the measured dose, despite the incidence radiation angle or the beta energy. Previous studies show that the Al2O3:C dosimeters present a very high energy dependence that can be minimized by using filters. This work aims to compare the angular dependence of commercial Al2O3:C dosimeters with and without the filters used to minimize the beta energy dependence of Al2O3:C, when the detectors were exposed to standard beta beams. The beta irradiations of the OSL detectors were performed using the beta secondary standard system of the Calibration Laboratory at IPEN, with 90Sr + 90Y, 85Kr and 147Pm sources, manufactured by Buchler GmbH and Co, Germany, calibrated by the primary standard laboratory Physikalisch-Technische Bundesanstalt (PTB), Germany. The OSL measurements were evaluated using a microStar reader and software of Landauer. The angular dependence was determined by using a goniometer. The incident radiation angle was varied from 0 deg to 180 deg. The results show that that the angular dependence curves present similar behavior, despite the use of filters

  10. Use of the Lorentz-Boosted Frame Transformation to Simulate Free-Electron Laser Amplifier Physics

    International Nuclear Information System (INIS)

    Recently it has been pointed out that numerical simulation of some systems containing charged particles with highly relativistic directed motion can by speeded up by orders of magnitude by choice of the proper Lorentz boosted frame. A particularly good example is that of short wavelength free-electron lasers (FELs) in which a high energy (E0 (ge) 250 MeV) electron beam interacts with a static magnetic undulator. In the optimal boost frame with Lorentz factor gamma F, the red-shifted FEL radiation and blue shifted undulator have identical wavelengths and the number of required time-steps (presuming the Courant condition applies) decreases by a factor of g2 F for fully electromagnetic simulation. We have adapted the WARP code to apply this method to several FEL problems including coherent spontaneous emission (CSE) from pre-bunched e-beams, and strong exponential gain in a single pass amplifier configuration. We discuss our results and compare with those from the 'standard' FEL simulation approach which adopts the eikonal approximation for propagation of the radiation field

  11. Evaluation of toxicity reduction of sodium dodecyl sulfate submitted to electron beam radiation

    International Nuclear Information System (INIS)

    Surfactants, as detergent active substances, are an important source of pollution causing biological adverse effects to aquatic organisms. Several data have been showing ecological disturbance due to the high concentration of surfactants on receiving waters and on wastewater treatment plants. Ionizing radiation has been proved as an effective technology to decompose organic substances and few papers have included ecotoxicological aspects. This paper shows the reduction of acute toxicity of a specific surfactant, sodium dodecyl sulfate (SDS), when diluted in distilled water and submitted to electron beam radiation. The study included two test-organisms, the marine bacteria Vibrio fischeri and the crustacean Daphnia similis. Radiation processing resulted in an important acute toxicity removal for both assays, which can be summarized between 70% and 96%, using 3.0, 6.0, 9.0 and 12.0 kGy as radiation doses. Nevertheless, lower doses demonstrated better effect than 9.0 and 12.0 kGy and the bacterium assay was more sensitive to SDS than crustacean assay

  12. Evaluation of kinetic parameters of PAN fibre modified by electron beam radiation

    International Nuclear Information System (INIS)

    Carbon fibers used for structural application are about 90% based on polyacrylonitrile (PAN) precursors due to their physical and mechanical properties. The thermal process is the conventional way to obtain a carbon fiber from PAN precursors. However, the use of ionizing radiation is given as an alternative technology to improve the physical and mechanical properties of the resulting carbon fiber. The aim of this paper was to obtain kinetic parameters (activation energy, conversion and isoconversion data) from DSC curves of PAN fibers irradiated with electron beam (EB) at different doses using the software Model Free Kinetics. The EB irradiation doses applied were: 0.2; 0.4; 0.6; 0.8; 1.0 and 1.2 MGy. The effect of ionizing radiation was evaluated by the thermal behavior of PAN precursors studied by Differential Scanning Calorimetry (DSC), which presents an exothermic peak in the range of 200 deg C to 400 deg C, depending on the experimental conditions of the DSC measurements. The obtained results showed that non-irradiated PAN fiber needs higher temperatures or longer reaction times to reach the same conversion degrees of the irradiated PAN fibers. Among the irradiated fibers, the reaction times decrease as a function of the radiation dose applied. However, the most important changes were observed for doses up to 0.4 MGy. The experimental results indicate that the EB radiation induces modification in the PAN fibers, which became them more liable in the oxidation process. (author)

  13. Ion beam characterization of advanced luminescent materials for application in radiation effects microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Branson, J.V., E-mail: jvbrans@sandia.gov [Sandia National Laboratories, P.O. Box 5800 MS 1056, Albuquerque, NM 87185-1056 (United States); Hattar, K. [Sandia National Laboratories, P.O. Box 5800 MS 1056, Albuquerque, NM 87185-1056 (United States); Rossi, P. [Sandia National Laboratories, P.O. Box 5800 MS 1056, Albuquerque, NM 87185-1056 (United States); Department of Physics of the University of Padua and INFN, via Marzolo 8, 35131 Padua (Italy); Vizkelethy, G.; Powell, C.J. [Sandia National Laboratories, P.O. Box 5800 MS 1056, Albuquerque, NM 87185-1056 (United States); Hernandez-Sanchez, B. [Sandia National Laboratories, P.O. Box 5800 MS 1349, Albuquerque, NM 87185-1349 (United States); Doyle, B.L. [Sandia National Laboratories, P.O. Box 5800 MS 1056, Albuquerque, NM 87185-1056 (United States)

    2011-10-15

    The ion photon emission microscope (IPEM) is a technique developed at Sandia National Laboratories (SNL) to study radiation effects in integrated circuits with high energy, heavy ions, such as those produced by the 88' cyclotron at Lawrence Berkeley National Laboratory (LBNL). In this method, an ion-luminescent film is used to produce photons from the point of ion impact. The photons emitted due to an ion impact are imaged on a position-sensitive detector to determine the location of a single event effect (SEE). Due to stringent resolution, intensity, wavelength, decay time, and radiation tolerance demands, an engineered material with very specific properties is required to act as the luminescent film. The requirements for this material are extensive. It must produce a high enough induced luminescent intensity so at least one photon is detected per ion hit. The emission wavelength must match the sensitivity of the detector used, and the luminescent decay time must be short enough to limit accidental coincidences. In addition, the material must be easy to handle and its luminescent properties must be tolerant to radiation damage. Materials studied for this application include plastic scintillators, GaN and GaN/InGaN quantum well structures, and lanthanide-activated ceramic phosphors. Results from characterization studies on these materials will be presented; including photoluminescence, cathodoluminescence, ion beam induced luminescence, luminescent decay times, and radiation damage. Results indicate that the ceramic phosphors are currently proving to be the ideal material for IPEM investigations.

  14. One-dimensional carbon nanostructures for terahertz electron-beam radiation

    Science.gov (United States)

    Tantiwanichapan, Khwanchai; Swan, Anna K.; Paiella, Roberto

    2016-06-01

    One-dimensional carbon nanostructures such as nanotubes and nanoribbons can feature near-ballistic electronic transport over micron-scale distances even at room temperature. As a result, these materials provide a uniquely suited solid-state platform for radiation mechanisms that so far have been the exclusive domain of electron beams in vacuum. Here we consider the generation of terahertz light based on two such mechanisms, namely, the emission of cyclotronlike radiation in a sinusoidally corrugated nanowire (where periodic angular motion is produced by the mechanical corrugation rather than an externally applied magnetic field), and the Smith-Purcell effect in a rectilinear nanowire over a dielectric grating. In both cases, the radiation properties of the individual charge carriers are investigated via full-wave electrodynamic simulations, including dephasing effects caused by carrier collisions. The overall light output is then computed with a standard model of charge transport for two particularly suitable types of carbon nanostructures, i.e., zigzag graphene nanoribbons and armchair single-wall nanotubes. Relatively sharp emission peaks at geometrically tunable terahertz frequencies are obtained in each case. The corresponding output powers are experimentally accessible even with individual nanowires, and can be scaled to technologically significant levels using array configurations. These radiation mechanisms therefore represent a promising paradigm for light emission in condensed matter, which may find important applications in nanoelectronics and terahertz photonics.

  15. Evaluation of toxicity reduction of sodium dodecyl sulfate submitted to electron beam radiation

    Science.gov (United States)

    Romanelli, M. F.; Moraes, M. C. F.; Villavicencio, A. L. C. H.; Borrely, S. I.

    2004-09-01

    Surfactants, as detergent active substances, are an important source of pollution causing biological adverse effects to aquatic organisms. Several data have been showing ecological disturbance due to the high concentration of surfactants on receiving waters and on wastewater treatment plants. Ionizing radiation has been proved as an effective technology to decompose organic substances and few papers have included ecotoxicological aspects. This paper shows the reduction of acute toxicity of a specific surfactant, sodium dodecyl sulfate (SDS), when diluted in distilled water and submitted to electron beam radiation. The study included two test-organisms, the marine bacteria Vibrio fischeri and the crustacean Daphnia similis. Radiation processing resulted in an important acute toxicity removal for both assays, which can be summarized between 70% and 96%, using 3.0, 6.0, 9.0 and 12.0 kGy as radiation doses. Nevertheless, lower doses demonstrated better effect than 9.0 and 12.0 kGy and the bacterium assay was more sensitive to SDS than crustacean assay.

  16. Evaluation of toxicity reduction of sodium dodecyl sulfate submitted to electron beam radiation

    Energy Technology Data Exchange (ETDEWEB)

    Romanelli, M.F. E-mail: mfromane@ipen.br; Moraes, M.C.F.; Villavicencio, A.L.C.H.; Borrely, S.I

    2004-10-01

    Surfactants, as detergent active substances, are an important source of pollution causing biological adverse effects to aquatic organisms. Several data have been showing ecological disturbance due to the high concentration of surfactants on receiving waters and on wastewater treatment plants. Ionizing radiation has been proved as an effective technology to decompose organic substances and few papers have included ecotoxicological aspects. This paper shows the reduction of acute toxicity of a specific surfactant, sodium dodecyl sulfate (SDS), when diluted in distilled water and submitted to electron beam radiation. The study included two test-organisms, the marine bacteria Vibrio fischeri and the crustacean Daphnia similis. Radiation processing resulted in an important acute toxicity removal for both assays, which can be summarized between 70% and 96%, using 3.0, 6.0, 9.0 and 12.0 kGy as radiation doses. Nevertheless, lower doses demonstrated better effect than 9.0 and 12.0 kGy and the bacterium assay was more sensitive to SDS than crustacean assay.

  17. Diversity-Based Boosting Algorithm

    Directory of Open Access Journals (Sweden)

    Jafar A. Alzubi

    2016-05-01

    Full Text Available Boosting is a well known and efficient technique for constructing a classifier ensemble. An ensemble is built incrementally by altering the distribution of training data set and forcing learners to focus on misclassification errors. In this paper, an improvement to Boosting algorithm called DivBoosting algorithm is proposed and studied. Experiments on several data sets are conducted on both Boosting and DivBoosting. The experimental results show that DivBoosting is a promising method for ensemble pruning. We believe that it has many advantages over traditional boosting method because its mechanism is not solely based on selecting the most accurate base classifiers but also based on selecting the most diverse set of classifiers.

  18. Boosting Support Vector Machines

    Directory of Open Access Journals (Sweden)

    Elkin Eduardo García Díaz

    2006-11-01

    Full Text Available En este artículo, se presenta un algoritmo de clasificación binaria basado en Support Vector Machines (Máquinas de Vectores de Soporte que combinado apropiadamente con técnicas de Boosting consigue un mejor desempeño en cuanto a tiempo de entrenamiento y conserva características similares de generalización con un modelo de igual complejidad pero de representación más compacta./ In this paper we present an algorithm of binary classification based on Support Vector Machines. It is combined with a modified Boosting algorithm. It run faster than the original SVM algorithm with a similar generalization error and equal complexity model but it has more compact representation.

  19. Analytic Boosted Boson Discrimination

    CERN Document Server

    Larkoski, Andrew J; Neill, Duff

    2015-01-01

    Observables which discriminate boosted topologies from massive QCD jets are of great importance for the success of the jet substructure program at the Large Hadron Collider. Such observables, while both widely and successfully used, have been studied almost exclusively with Monte Carlo simulations. In this paper we present the first all-orders factorization theorem for a two-prong discriminant based on a jet shape variable, $D_2$, valid for both signal and background jets. Our factorization theorem simultaneously describes the production of both collinear and soft subjets, and we introduce a novel zero-bin procedure to correctly describe the transition region between these limits. By proving an all orders factorization theorem, we enable a systematically improvable description, and allow for precision comparisons between data, Monte Carlo, and first principles QCD calculations for jet substructure observables. Using our factorization theorem, we present numerical results for the discrimination of a boosted $Z...

  20. Design of a synchrotron radiation detector for the test beam lines at the Superconducting Super Collider Laboratory

    International Nuclear Information System (INIS)

    As part of the particle- and momentum-tagging instrumentation required for the test beam lines of the Superconducting Super Collider (SSC), the synchrotron radiation detector (SRD) was designed to provide electron tagging at momentum above 75 GeV. In a parallel effort to the three test beam lines at the SSC, schedule demands required testing and calibration operations to be initiated at Fermilab. Synchrotron radiation detectors also were to be installed in the NM and MW beam lines at Femilab before the test beam lines at the SSC would become operational. The SRD is the last instrument in a series of three used in the SSC test beam fines. It follows a 20-m drift section of beam tube downstream of the last silicon strip detector. A bending dipole just in of the last silicon strip detector produces the synchrotron radiation that is detected in a 50-mm-square cross section NaI crystal. A secondary scintillator made of Bicron BC-400 plastic is used to discriminate whether it is synchrotron radiation or a stray particle that causes the triggering of the NaI crystal's photo multiplier tube (PMT)

  1. Physiologically gated micro-beam radiation therapy using electronically controlled field emission x-ray source array

    Science.gov (United States)

    Chtcheprov, Pavel; Hadsell, Michael; Burk, Laurel; Ger, Rachel; Zhang, Lei; Yuan, Hong; Lee, Yueh Z.; Chang, Sha; Lu, Jianping; Zhou, Otto

    2013-03-01

    Micro-beam radiation therapy (MRT) uses parallel planes of high dose narrow (10-100 um in width) radiation beams separated by a fraction of a millimeter to treat cancerous tumors. This experimental therapy method based on synchrotron radiation has been shown to spare normal tissue at up to 1000Gy of entrance dose while still being effective in tumor eradication and extending the lifetime of tumor-bearing small animal models. Motion during the treatment can result in significant movement of micro beam positions resulting in broader beam width and lower peak to valley dose ratio (PVDR), and thus can reduce the effectiveness of the MRT. Recently we have developed the first bench-top image guided MRT system for small animal treatment using a high powered carbon nanotube (CNT) x-ray source array. The CNT field emission x-ray source can be electronically synchronized to an external triggering signal to enable physiologically gated firing of x-ray radiation to minimize motion blurring. Here we report the results of phantom study of respiratory gated MRT. A simulation of mouse breathing was performed using a servo motor. Preliminary results show that without gating the micro beam full width at tenth maximum (FWTM) can increase by 70% and PVDR can decrease up to 50%. But with proper gating, both the beam width and PVDR changes can be negligible. Future experiments will involve irradiation of mouse models and comparing histology stains between the controls and the gated irradiation.

  2. Analytic boosted boson discrimination

    OpenAIRE

    Andrew J. Larkoski; Moult, Ian; Neill, Duff

    2015-01-01

    Observables which discriminate boosted topologies from massive QCD jets are of great importance for the success of the jet substructure program at the Large Hadron Collider. Such observables, while both widely and successfully used, have been studied almost exclusively with Monte Carlo simulations. In this paper we present the first all-orders factorization theorem for a two-prong discriminant based on a jet shape variable, $D_2$, valid for both signal and background jets. Our factorization t...

  3. SUSY using boosted techniques

    CERN Document Server

    Stark, Giordon; The ATLAS collaboration

    2016-01-01

    In this talk, I present a discussion of techniques used in supersymmetry searches in papers published by the ATLAS Collaboration from late Run 1 to early Run 2. The goal is to highlight concepts the analyses have in common, why/how they work, and possible SUSY searches that could benefit from boosted studies. Theoretical background will be provided for reference to encourage participants to explore in depth on their own time.

  4. Measurement of transverse beam parameters at X-ray diagnostic beamlines in Indus-2 synchrotron radiation source

    International Nuclear Information System (INIS)

    Indus-2 is a 3rd generation synchrotron radiation source at RRCAT, Indore with 2.5 GeV energy and 200 mA beam current. The average beam sizes of electron beam are a few hundred micrometers (∼ 250 μn) in the transverse plane. In Indus-2, various types of diagnostic devices have been installed in the storage ring for the measurement of beam orbit, beam profile, beam current, tune etc. To further enhance the performance of the beam diagnostic system, two diagnostic beamlines have been designed and developed viz. X-ray diagnostic beamline (X-DBL) and visible diagnostic beamline (V- DBL). Beamline BL-24 at 10° port of bending magnet (DP-10) of Indus-2 storage ring has been developed as X-DBL. X-DBL is based on x-ray imaging (8-18 keV) with a pinhole array system. It is primarily used for beam size, beam emittance and beam position measurement. In X-ray diagnostic beamline a LabVIEW based graphical user interface (Gill) has been developed for online image processing and measurement of various beam parameters. Beamline is used routinely for the online measurements of beam sizes, beam emittance and beam stability. Measured data is analyzed to find changes in SR source point parameters under different conditions of the beam operation. In the present optics setting, typical measured beam size (RMS) is 440 ± 20 μnm horizontal and 55 ± 5 μm vertical, and correspondingly typical measured emittance is 155 ± 20 nm rad horizontal and 0.4 ± 0.05 nm rad vertical during the natural decay of beam current from 120 mA to 40 mA. Beam position remains stable within ± 20 μm horizontal and ± 15 μm vertical during the natural decay of beam current in Indus-2. Photon beam position (at 8 m from source point) remains stable within ± 20 μm during this natural decay of beam current. In this paper various measurement results of the beamline are described. (author)

  5. Analysis of X-ray beam parameters used to implement reference radiations for calibrating dosimetric systems for diagnostic radiology

    International Nuclear Information System (INIS)

    Ionizing radiation metrology is the base to achieve reliable dose measurements in all areas; it is also part of the framework of a radiological protection program that requires the use of reliable instruments that comply with standard performance criteria worldwide accepted. The International Electrotechnical Commission (IEC) established the X-ray reference radiations that are recommended to be used for calibrating dosimetric systems for diagnostic dosimetry. In this work, X-ray beam qualities were implemented in the Dosimeter Calibration Laboratory of the Development Centre of Nuclear Technology; the characteristics of the beams were analyzed through the measurement of parameters like inherent tube filtration, beam uniformity; beam field size, energy spectra and peak voltage. The influence of using 99.425% and 99.999% purity filters was also investigated. The first half-value layers and the homogeneity coefficients were measured for the three RQR2, RQR6 and RQR10 IEC beam qualities. An ionization chamber was also calibrated against a standard chamber in all implemented reference radiations and the relevant sources of uncertainties were estimated. Beam parameters were adjusted to comply with IEC standard; the main source of uncertainty during the calibration process was due to the ionization chamber positioning set-up and the purity of the filters did not cause relevant influence on the beam energy spectra. (author)

  6. Intraoperative Electron-Beam Radiation Therapy for Pediatric Ewing Sarcomas and Rhabdomyosarcomas: Long-Term Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Sole, Claudio V., E-mail: csole@iram.cl [Department of Radiation Oncology, Instituto de Radiomedicina, Santiago (Chile); School of Medicine, Complutense University, Madrid (Spain); Calvo, Felipe A. [School of Medicine, Complutense University, Madrid (Spain); Department of Oncology, Hospital General Universitario Gregorio Marañón, Madrid (Spain); Polo, Alfredo [Service of Radiation Oncology, Hospital Universitario Ramón y Cajal, Madrid (Spain); Cambeiro, Mauricio [Service of Radiation Oncology, Clínica Universidad de Navarra, Pamplona (Spain); Gonzalez, Carmen [School of Medicine, Complutense University, Madrid (Spain); Service of Radiation Oncology, Hospital General Universitario Gregorio Marañón, Madrid (Spain); Desco, Manuel [School of Medicine, Complutense University, Madrid (Spain); Department of Experimental Surgery and Medicine, Hospital General Universitario Gregorio Marañón, Madrid (Spain); Martinez-Monge, Rafael [Service of Radiation Oncology, Clínica Universidad de Navarra, Pamplona (Spain)

    2015-08-01

    Purpose: To assess long-term outcomes and toxicity of intraoperative electron-beam radiation therapy (IOERT) in the management of pediatric patients with Ewing sarcomas (EWS) and rhabdomyosarcomas (RMS). Methods and Materials: Seventy-one sarcoma (EWS n=37, 52%; RMS n=34, 48%) patients underwent IOERT for primary (n=46, 65%) or locally recurrent sarcomas (n=25, 35%) from May 1983 to November 2012. Local control (LC), overall survival (OS), and disease-free survival were estimated using Kaplan-Meier methods. For survival outcomes, potential associations were assessed in univariate and multivariate analyses using the Cox proportional hazards model. Results: After a median follow-up of 72 months (range, 4-310 months), 10-year LC, disease-free survival, and OS was 74%, 57%, and 68%, respectively. In multivariate analysis after adjustment for other covariates, disease status (P=.04 and P=.05) and R1 margin status (P<.01 and P=.04) remained significantly associated with LC and OS. Nine patients (13%) reported severe chronic toxicity events (all grade 3). Conclusions: A multimodal IOERT-containing approach is a well-tolerated component of treatment for pediatric EWS and RMS patients, allowing reduction or substitution of external beam radiation exposure while maintaining high local control rates.

  7. Radiation therapy with laser-driven accelerated particle beams: physical dosimetry and spatial dose distribution

    International Nuclear Information System (INIS)

    One of the main goals of the Munich Centre for Advanced Photonics (MAP) is the application of laser driven accelerated (LDA) particle beams for radiation therapy. Due to the unique acceleration process ultrashort particle pulses of high intensity (> 107 particles /cm2/ns) are generated, which makes online detection an ambitious task. So far, state of the art detection of laser accelerated ion pulses are non-electronic detectors like radiochromic films (RCF), imaging plates (IP) or nuclear track detectors (e.g. CR39). All these kind of detectors are offline detectors requiring several hours of processing time. For this reason they are not qualified for an application in radiation therapy where quantitative real time detection of the beam is an essential prerequisite. Therefore we are investigating pixel detectors for real time monitoring of LDA particle pulses. First tests of commercially available systems with 8-20 MeV protons are presented. For radiobiological experiments second generation Gafchromic films (EBT2) have been calibrated with protons of 12 and 20 MeV for a dose range of 0.3-10 Gy. Dose verification in proton irradiation of subcutaneous tumours in mice was successfully accomplished using these films.

  8. Multichannel Data Acquisition System comparison for Quality Assurance in external beam radiation therapy

    International Nuclear Information System (INIS)

    Megavoltage photon radiation therapies are widely used in modern cancer treatment. The improvement of the treatment has lead to the need of Quality Assurance (QA) devices to detect malfunctioning or human mistakes during the planning phase and treatment verification. Active electronic devices for 2D or 3D QA in external beam radiotherapy are typically based on analogue/digital mixed signal Data Acquisition Systems (DAS) which are required to have high spatial resolution, large dynamic range, high sensitivity, large numbers of channels and fast real-time capabilities. The Centre of Medical Radiation Physics (CMRP) has developed several multichannel DAS architectures based on different analogue front-ends to suit a wide range of radiotherapy applications. For the purpose of this study, two DAS, with different front-ends, have been equipped with 128 channels and tested in a clinical environment. Data show a good agreement within 1% between the two systems and the ionising chamber currently used for daily QA. - Highlights: • Two multichannels Data Acquisition Systems (DAS A and B) have been designed by the CMRP for Quality Assurance purposes. • The DAS have been tested and compared to ion chamber showing agreement of the results within 1%. • DAS have been used to characterise megavoltage LINAC beam profile and timing performances

  9. Intraoperative Electron-Beam Radiation Therapy for Pediatric Ewing Sarcomas and Rhabdomyosarcomas: Long-Term Outcomes

    International Nuclear Information System (INIS)

    Purpose: To assess long-term outcomes and toxicity of intraoperative electron-beam radiation therapy (IOERT) in the management of pediatric patients with Ewing sarcomas (EWS) and rhabdomyosarcomas (RMS). Methods and Materials: Seventy-one sarcoma (EWS n=37, 52%; RMS n=34, 48%) patients underwent IOERT for primary (n=46, 65%) or locally recurrent sarcomas (n=25, 35%) from May 1983 to November 2012. Local control (LC), overall survival (OS), and disease-free survival were estimated using Kaplan-Meier methods. For survival outcomes, potential associations were assessed in univariate and multivariate analyses using the Cox proportional hazards model. Results: After a median follow-up of 72 months (range, 4-310 months), 10-year LC, disease-free survival, and OS was 74%, 57%, and 68%, respectively. In multivariate analysis after adjustment for other covariates, disease status (P=.04 and P=.05) and R1 margin status (P<.01 and P=.04) remained significantly associated with LC and OS. Nine patients (13%) reported severe chronic toxicity events (all grade 3). Conclusions: A multimodal IOERT-containing approach is a well-tolerated component of treatment for pediatric EWS and RMS patients, allowing reduction or substitution of external beam radiation exposure while maintaining high local control rates

  10. Radiation therapy with laser-driven accelerated particle beams: physical dosimetry and spatial dose distribution

    Energy Technology Data Exchange (ETDEWEB)

    Reinhardt, Sabine; Assmann, Walter [Ludwig-Maximilians Universitaet Muenchen (Germany); Kneschaurek, Peter; Wilkens, Jan [MRI, Technische Universitaet Muenchen (Germany)

    2011-07-01

    One of the main goals of the Munich Centre for Advanced Photonics (MAP) is the application of laser driven accelerated (LDA) particle beams for radiation therapy. Due to the unique acceleration process ultrashort particle pulses of high intensity (> 10{sup 7} particles /cm{sup 2}/ns) are generated, which makes online detection an ambitious task. So far, state of the art detection of laser accelerated ion pulses are non-electronic detectors like radiochromic films (RCF), imaging plates (IP) or nuclear track detectors (e.g. CR39). All these kind of detectors are offline detectors requiring several hours of processing time. For this reason they are not qualified for an application in radiation therapy where quantitative real time detection of the beam is an essential prerequisite. Therefore we are investigating pixel detectors for real time monitoring of LDA particle pulses. First tests of commercially available systems with 8-20 MeV protons are presented. For radiobiological experiments second generation Gafchromic films (EBT2) have been calibrated with protons of 12 and 20 MeV for a dose range of 0.3-10 Gy. Dose verification in proton irradiation of subcutaneous tumours in mice was successfully accomplished using these films.

  11. Ultrasonic Beam Radiation of an A0 Leaky Lamb Wave in a Plate Waveguide Sensor

    International Nuclear Information System (INIS)

    As the sodium coolant of a sodium-cooled fast reactor (SFR) is opaque to light, a conventional visual inspection cannot be used for carrying out an in-service inspection of the internal structures under a sodium level. An ultrasonic wave should be applied for an under-sodium viewing of the internal structures in a reactor vessel. Immersion sensors and waveguide sensors have been applied to the under-sodium visualization. The immersion sensor has a precise imaging capability, but may have high temperature restrictions and an uncertain life. The waveguide sensor has the advantages of a long lifetime and stable application. Recently, a new plate waveguide sensor has been developed for the versatile applications in the under-sodium viewing application. In the plate waveguide sensor, the A0 leaky Lamb wave is utilized for the long distance propagation and the effective radiation capability in a fluid. And a new technique is presented which is capable of steering an ultrasonic beam of a waveguide sensor without a mechanical movement of the sensor assembly. In this paper, the experimental study of the radiation beam profile of the A0 leaky Lamb wave in a plate waveguide sensor is carried out

  12. Optical dosimetry of radiotherapy beams using Cherenkov radiation: the relationship between light emission and dose

    International Nuclear Information System (INIS)

    Recent studies have proposed that light emitted by the Cherenkov effect may be used for a number of radiation therapy dosimetry applications. There is a correlation between the captured light and expected dose under certain conditions, yet discrepancies have also been observed and a complete examination of the theoretical differences has not been done. In this study, a fundamental comparison between the Cherenkov emission and absorbed dose was explored for x-ray photons, electrons, and protons using both a theoretical and Monte Carlo-based analysis. Based on the findings of where dose correlates with Cherenkov emission, it was concluded that for x-ray photons the light emission would be optimally suited for narrow beam stereotactic radiation therapy and surgery validation studies, for verification of dynamic intensity-modulated and volumetric modulated arc therapy treatment plans in water tanks, near monoenergetic sources (e.g., Co-60 and brachy therapy sources) and also for entrance and exit surface imaging dosimetry of both narrow and broad beams. For electron use, Cherenkov emission was found to be only suitable for surface dosimetry applications. Finally, for proton dosimetry, there exists a fundamental lack of Cherenkov emission at the Bragg peak, making the technique of little use, although post-irradiation detection of light emission from radioisotopes could prove to be useful. (paper)

  13. StructBoost: Boosting Methods for Predicting Structured Output Variables.

    Science.gov (United States)

    Chunhua Shen; Guosheng Lin; van den Hengel, Anton

    2014-10-01

    Boosting is a method for learning a single accurate predictor by linearly combining a set of less accurate weak learners. Recently, structured learning has found many applications in computer vision. Inspired by structured support vector machines (SSVM), here we propose a new boosting algorithm for structured output prediction, which we refer to as StructBoost. StructBoost supports nonlinear structured learning by combining a set of weak structured learners. As SSVM generalizes SVM, our StructBoost generalizes standard boosting approaches such as AdaBoost, or LPBoost to structured learning. The resulting optimization problem of StructBoost is more challenging than SSVM in the sense that it may involve exponentially many variables and constraints. In contrast, for SSVM one usually has an exponential number of constraints and a cutting-plane method is used. In order to efficiently solve StructBoost, we formulate an equivalent 1-slack formulation and solve it using a combination of cutting planes and column generation. We show the versatility and usefulness of StructBoost on a range of problems such as optimizing the tree loss for hierarchical multi-class classification, optimizing the Pascal overlap criterion for robust visual tracking and learning conditional random field parameters for image segmentation. PMID:26352637

  14. External beam radiation therapy for the treatment of subretinal neovascularization: experience with 140 patients

    International Nuclear Information System (INIS)

    Purpose/Objectives: Several clinical series with relatively small numbers of patients and short durations of follow-up have demonstrated that external beam radiation may be effective in treating subretinal neovascularization, a major cause of blindness in the U.S. This prospective study evaluates the efficacy of this treatment in a larger cohort of patients with a longer duration of follow-up than any previously reported series. Materials and Methods: One hundred forty patients between the ages of 50 and 96 were enrolled in this study between March 1994 and March 1996. Forty patients had previously undergone laser photocoagulation for subretinal neovascularization at other sites. Pretreatment visual acuity in the irradiated eyes was at least (20(400)). Prior to the initiation of external beam radiation therapy all patients underwent fluorocein angiography and indirect ophthalmoscopy to document the extent of neovascularization. Treatments were administered via single lateral photon beams of 4 - 6 MV energy, angled 5 degree sign - 10 degree sign posteriorly to avoid the anterior segment of the contralateral eye. Seventy-five patients received 1400 - 1500 cGy in 7-8 fractions while the remaining 65 patients received 1800 cGy in 9-10 fractions. Results: Transient epiphora and conjunctival irritation appeared to be more common in patients receiving 1800 cGy as opposed to 1400 - 1500 cGy. All patients underwent repeat ophthalmoscopy and angiography at three month intervals following treatment. Within three months of treatment, we noted regression or stabilization of retinal hemorrhages and exudates in over 85% of patients. Approximately 75% of patients followed for at least six months have maintained within two lines of their pre-treatment visual acuity. There was no significant difference in response to treatment between the 1400 - 1500 cGy and 1800 cGy arms. Conclusion: This study includes more patients with longer follow-up than any previously reported series. It

  15. Partial Breast Radiation Therapy With Proton Beam: 5-Year Results With Cosmetic Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Bush, David A., E-mail: dbush@llu.edu [Department of Radiation Oncology, Loma Linda University Medical Center, Loma Linda, California (United States); Do, Sharon [Department of Radiation Oncology, Loma Linda University Medical Center, Loma Linda, California (United States); Lum, Sharon; Garberoglio, Carlos [Department of Surgical Oncology, Loma Linda University Medical Center, Loma Linda, California (United States); Mirshahidi, Hamid [Department of Medical Oncology, Loma Linda University Medical Center, Loma Linda, California (United States); Patyal, Baldev; Grove, Roger; Slater, Jerry D. [Department of Radiation Oncology, Loma Linda University Medical Center, Loma Linda, California (United States)

    2014-11-01

    Purpose: We updated our previous report of a phase 2 trial using proton beam radiation therapy to deliver partial breast irradiation (PBI) in patients with early stage breast cancer. Methods and Materials: Eligible subjects had invasive nonlobular carcinoma with a maximal dimension of 3 cm. Patients underwent partial mastectomy with negative margins; axillary lymph nodes were negative on sampling. Subjects received postoperative proton beam radiation therapy to the surgical bed. The dose delivered was 40 Gy in 10 fractions, once daily over 2 weeks. Multiple fields were treated daily, and skin-sparing techniques were used. Following treatment, patients were evaluated with clinical assessments and annual mammograms to monitor toxicity, tumor recurrence, and cosmesis. Results: One hundred subjects were enrolled and treated. All patients completed the assigned treatment and were available for post-treatment analysis. The median follow-up was 60 months. Patients had a mean age of 63 years; 90% had ductal histology; the average tumor size was 1.3 cm. Actuarial data at 5 years included ipsilateral breast tumor recurrence-free survival of 97% (95% confidence interval: 100%-93%); disease-free survival of 94%; and overall survival of 95%. There were no cases of grade 3 or higher acute skin reactions, and late skin reactions included 7 cases of grade 1 telangiectasia. Patient- and physician-reported cosmesis was good to excellent in 90% of responses, was not changed from baseline measurements, and was well maintained throughout the entire 5-year follow-up period. Conclusions: Proton beam radiation therapy for PBI produced excellent ipsilateral breast recurrence-free survival with minimal toxicity. The treatment proved to be adaptable to all breast sizes and lumpectomy cavity configurations. Cosmetic results appear to be excellent and unchanged from baseline out to 5 years following treatment. Cosmetic results may be improved over those reported with photon

  16. Partial Breast Radiation Therapy With Proton Beam: 5-Year Results With Cosmetic Outcomes

    International Nuclear Information System (INIS)

    Purpose: We updated our previous report of a phase 2 trial using proton beam radiation therapy to deliver partial breast irradiation (PBI) in patients with early stage breast cancer. Methods and Materials: Eligible subjects had invasive nonlobular carcinoma with a maximal dimension of 3 cm. Patients underwent partial mastectomy with negative margins; axillary lymph nodes were negative on sampling. Subjects received postoperative proton beam radiation therapy to the surgical bed. The dose delivered was 40 Gy in 10 fractions, once daily over 2 weeks. Multiple fields were treated daily, and skin-sparing techniques were used. Following treatment, patients were evaluated with clinical assessments and annual mammograms to monitor toxicity, tumor recurrence, and cosmesis. Results: One hundred subjects were enrolled and treated. All patients completed the assigned treatment and were available for post-treatment analysis. The median follow-up was 60 months. Patients had a mean age of 63 years; 90% had ductal histology; the average tumor size was 1.3 cm. Actuarial data at 5 years included ipsilateral breast tumor recurrence-free survival of 97% (95% confidence interval: 100%-93%); disease-free survival of 94%; and overall survival of 95%. There were no cases of grade 3 or higher acute skin reactions, and late skin reactions included 7 cases of grade 1 telangiectasia. Patient- and physician-reported cosmesis was good to excellent in 90% of responses, was not changed from baseline measurements, and was well maintained throughout the entire 5-year follow-up period. Conclusions: Proton beam radiation therapy for PBI produced excellent ipsilateral breast recurrence-free survival with minimal toxicity. The treatment proved to be adaptable to all breast sizes and lumpectomy cavity configurations. Cosmetic results appear to be excellent and unchanged from baseline out to 5 years following treatment. Cosmetic results may be improved over those reported with photon

  17. Beam test of novel n-in-p strip sensors for high radiation environment

    International Nuclear Information System (INIS)

    Highly radiation tolerant n-in-p strip sensors have been developed for the high-luminosity LHC (HL-LHC). This paper reports the results of measurements with 392 MeV kinetic energy proton beam at RCNP in December 2011. The data was taken with a new DAQ system consisting of an universal read-out board ‘SEABAS’ and beam tracking telescopes whose spacial resolution is better than 5μm. The aim of this beam test is to evaluate the new 1 cm×1 cm n-in-p miniature sensors before and after 1015 neq cm−2 irradiation. The median charge of un-irradiated sensor is 6.2 fC at full depletion voltage, while the median charge after 1015 neq cm−2 irradiation of the sensor is 4.2 fC. The novel Punch-Through-Protection (PTP) has been implemented in these sensors. The length of active region of the sensor around PTP is observed to be decreased by 12μm in the irradiated sensors at 1015 neq cm−2

  18. Radiation damage of semi-conductor device using micro ion-beam

    Energy Technology Data Exchange (ETDEWEB)

    Nishijima, Toshiji [Electrotechnical Lab., Tsukuba, Ibaraki (Japan)

    2001-02-01

    Ion beam induced charge collection (IBIC) analyzing method using fast micro ion-beam is a very useful technique for observation of interaction of fine solid materials for electronics with incident ions. This method is applied for development of semiconductor devices and investigation of single event upset phenomena (SEU) in an integrated circuit. To study on a basic process of the SEU, high energy ions are irradiated to the following three micro diode devices; silicon junction diode, silicon-on-insulator device (SOI), and SiC Schottky barrier diode. Transient currents induced in the micro diode devices by He{sup +} ion incidence of 2 MeV are measured through a charge sensitive preamplifier and a linear amplifier. The current signals are digitized by an analog to digital converter and measured by using a pulse height analyzer. The micro ion-beam are irradiated within the area of 10 {mu} m{sup 2} on the diode devices with 1-2 particles/ {mu} m{sup 2} by using the IBIC technique. Radiation damage of the diodes can be measured with the IBIC current pulse height. SiC Schottky barrier diode is unstable on the ion irradiation in comparison with Si junction diode and SOI junction diode. The SOI junction diode is stable within the range of irradiation rate, 3.7E+10 - 3.7E+12 ions/cm{sup 2}. (M. Suetake)

  19. Improving the Fermilab Booster Notching Efficiency, Beam Losses and Radiation Levels

    CERN Document Server

    Rakhno, I L; Mokhov, N V; Sidorov, V I; Tropin, I S

    2012-01-01

    Currently a fast vertical 1.08-m long kicker (notcher) located in the Fermilab Booster Long-5 straight section is used to remove 3 out of 84 circulating bunches after injection to generate an abort gap. With magnetic field of 72.5 Gauss it removes only 87% of the 3-bunch intensity at 400 MeV, with 75% loss on pole tips of the focusing Booster magnets, 11% on the Long-6 collimators, and 1% in the rest of the ring. We propose to improve the notching efficiency and reduce beam loss in the Booster by using two horizontal kickers in the Long-12 section. The STRUCT calculations show that using such horizontal notchers, one can remove up to 99% of the 3-bunch intensity at 400-700 MeV, directing 96% of it to a new beam dump at the Long-13 section. This fully decouples notching and collimation. The beam dump absorbs most of the impinging proton energy in its jaws. The latter are encapsulated into an appropriate radiation shielding that reduces impact on the machine components, personnel and environment to the tolerabl...

  20. External beam radiation therapy followed by high-dose-rate brachytherapy for inoperable superficial esophageal carcinoma

    International Nuclear Information System (INIS)

    Purpose: The aim of this study was to retrospectively evaluate the feasibility, efficacy, and tolerance of external beam radiotherapy followed by high-dose-rate brachytherapy in inoperable patients with superficial esophageal cancer. Patients and Methods: From November 1992 to May 1999, 66 patients with superficial esophageal cancer were treated with exclusive radiotherapy. The median age was 60 years (range, 41-85). Fifty-three percent of them were ineligible for surgery owing to synchronous or previously treated head-and-neck cancer. Most of the patients (n = 49) were evaluated with endoscopic ultrasonography (EUS) or computed tomography (CT). The mean doses of external beam radiotherapy and high-dose rate brachytherapy were 57.1 Gy (±4.83) and 8.82 Gy (±3.98), respectively. The most frequently used regimen was 60 Gy followed by 7 Gy at 5 mm depth in two applications. Results: Among patients evaluated with EUS or CT, the complete response rate was 98%. The 3-, 5-, and 7-year survival rates were 57.9%, 35.6%, and 26.6%, respectively. Median overall survival was 3.8 years. The 5-year relapse-free survival and cause-specific survival were 54.6% and 76.9%. The 5-year overall, relapse-free, and cause-specific survival of the whole population of 66 patients was 33%, 53%, and 77%, respectively. Local failure occurred in 15 of 66 patients; 6 were treated with brachytherapy. Severe late toxicity (mostly esophageal stenosis) rated according to the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer scale occurred in 6 of 66 patients (9%). Conclusion: This well tolerated regimen may be a therapeutic alternative for inoperable patients with superficial esophageal cancer. Only a randomized study could be able to check the potential benefit of brachytherapy after external beam radiation in superficial esophageal cancer

  1. FULL ELECTROMAGNETIC SIMULATION OF FREE-ELECTRON LASER AMPLIFIER PHYSICS VIA THE LORENTZ-BOOSTED FRAME APPROACH

    International Nuclear Information System (INIS)

    Numerical simulation of some systems containing charged particles with highly relativistic directed motion can by speeded up by orders of magnitude by choice of the proper Lorentz-boosted frame. A particularly good example is that of short wavelength free-electron lasers (FELs) in which a high energy electron beam interacts with a static magnetic undulator. In the optimal boost frame with Lorentz factor gammaF, the red-shifted FEL radiation and blue shifted undulator have identical wavelengths and the number of required time-steps (presuming the Courant condition applies) decreases by a factor of 2(gammaF)**2 for fully electromagnetic simulation. We have adapted the WARP code to apply this method to several FEL problems involving coherent spontaneous emission (CSE) from pre-bunched ebeams, including that in a biharmonic undulator.

  2. Radiation environment simulations at the Tevatron, studies of the beam profile and measurement of the Bc meson mass

    Energy Technology Data Exchange (ETDEWEB)

    Nicolas, Ludovic Y.

    2005-09-01

    The description of a computer simulation of the CDF detector at Fermilab and the adjacent accelerator parts is detailed, with MARS calculations of the radiation background in various elements of the model due to the collision of beams and machine-related losses. Three components of beam halo formation are simulated for the determination of the principal source of radiation background in CDF due to beam losses. The effect of a collimator as a protection for the detector is studied. The simulation results are compared with data taken by a CDF group. Studies of a 150 GeV Tevatron proton beam are performed to investigate the transverse diffusion growth and distribution. A technique of collimator scan is used to scrape the beam under various experimental conditions, and computer programs are written for the beam reconstruction. An average beam halo growth speed is given and the potential of beam tail reconstruction using the collimator scan is evaluated. A particle physics analysis is conducted in order to detect the B{sub c} {yields} J/{psi}{pi} decay signal with the CDF Run II detector in 360 pb{sup -1} of data. The cut variables and an optimization method to determine their values are presented along with a criterion for the detection threshold of the signal. The mass of the B{sub c} meson is measured with an evaluation of the significance of the signal.

  3. Early breast cancer: influence of type of boost (electrons vs iridium-192 implant) on local control and cosmesis after conservative surgery and radiation therapy

    International Nuclear Information System (INIS)

    Between December 1981 and December 1988, 329 consecutive patients with stage I and II breast cancers who underwent wide excision (n = 261) or quadrantectomy (n = 68) with (n = 303) or without (n = 26) axillary dissection were referred to radiotherapy. Final margins of resection were microscopically free from tumor involvement in all cases. Radiotherapy consisted in 40-45 Gy over 4-4.5 weeks to the breast, with (n = 168) or without (n = 161) regional nodal irradiation of 45-50 Gy over 4.5-5 weeks. A mean booster dose of 15 Gy was delivered to the primary site by iridium-192 implant in 169 patients (group 1) or by electrons in 160 patients (group 2). Twenty-seven percent (n = 88) of patients received tamoxifen for ≥ 2 years. Adjuvant chemotherapy was administered in 22% (n = 71) of patients. Groups 1 and 2 were not strictly comparable. Group 1 patients were significantly younger, had smaller tumors, were treated with cobalt at 5 x 2 Gy per week and axillary dissection was more frequently performed. Group 2 patients were more frequently bifocal and more frequently treated by quadrantectomy and tamoxifen, and irradiation used accelerator photons at 4 x 2.50 Gy per week. No difference in terms of follow-up and survival rates was observed between the two groups. For all patients the 5- and 10-year local breast relapse rates were 6.7% and 11%, respectively. No difference was observed regarding local control either by the electron or the iridium-192 implant boosts. Axillary dissection and age had an impact on the breast cosmetic outcome. Furthermore, the cosmetic results seemed to be poorer in group 1 than in group 2. This may be related to other factors; group 1 patients were treated with telecobalt and axillary dissection was more frequently performed; on the other hand, group 2 patients were treated with accelarator photons

  4. A Novel Approach to Postmastectomy Radiation Therapy Using Scanned Proton Beams

    International Nuclear Information System (INIS)

    Purpose: Postmastectomy radiation therapy (PMRT), currently offered at Massachusetts General Hospital, uses proton pencil beam scanning (PBS) with intensity modulation, achieving complete target coverage of the chest wall and all nodal regions and reduced dose to the cardiac structures. This work presents the current methodology for such treatment and the ongoing effort for its improvements. Methods and Materials: A single PBS field is optimized to ensure appropriate target coverage and heart/lung sparing, using an in–house-developed proton planning system with the capability of multicriteria optimization. The dose to the chest wall skin is controlled as a separate objective in the optimization. Surface imaging is used for setup because it is a suitable surrogate for superficial target volumes. In order to minimize the effect of beam range uncertainties, the relative proton stopping power ratio of the material in breast implants was determined through separate measurements. Phantom measurements were also made to validate the accuracy of skin dose calculation in the treatment planning system. Additionally, the treatment planning robustness was evaluated relative to setup perturbations and patient breathing motion. Results: PBS PMRT planning resulted in appropriate target coverage and organ sparing, comparable to treatments by passive scattering (PS) beams but much improved in nodal coverage and cardiac sparing compared to conventional treatments by photon/electron beams. The overall treatment time was much shorter than PS and also shorter than conventional photon/electron treatment. The accuracy of the skin dose calculation by the planning system was within ±2%. The treatment was shown to be adequately robust relative to both setup uncertainties and patient breathing motion, resulting in clinically satisfying dose distributions. Conclusions: More than 25 PMRT patients have been successfully treated at Massachusetts General Hospital by using single-PBS fields

  5. Stereotactic body radiation therapy for liver tumours using flattening filter free beam: dosimetric and technical considerations

    Directory of Open Access Journals (Sweden)

    Mancosu Pietro

    2012-02-01

    Full Text Available Abstract Purpose To report the initial institute experience in terms of dosimetric and technical aspects in stereotactic body radiation therapy (SBRT delivered using flattening filter free (FFF beam in patients with liver lesions. Methods and Materials From October 2010 to September 2011, 55 consecutive patients with 73 primary or metastatic hepatic lesions were treated with SBRT on TrueBeam using FFF beam and RapidArc technique. Clinical target volume (CTV was defined on multi-phase CT scans, PET/CT, MRI, and 4D-CT. Dose prescription was 75 Gy in 3 fractions to planning target volume (PTV. Constraints for organs at risk were: 700 cc of liver free from the 15 Gy isodose, Dmax max 0.1 cc 15 Gy Results Forty-three patients with a single lesion, nine with two lesions and three with three lesions were treated with this protocol. Target and organs at risk objectives were met for all patients. Mean delivery time was 2.8 ± 1.0 min. Pre-treatment plan verification resulted in a Gamma Agreement Index of 98.6 ± 0.8%. Mean on-line co-registration shift of the daily CBCT to the simulation CT were: -0.08, 0.05 and -0.02 cm with standard deviations of 0.33, 0.39 and 0.55 cm in, vertical, longitudinal and lateral directions respectively. Conclusions SBRT for liver targets delivered by means of FFF resulted to be feasible with short beam on time.

  6. A Novel Approach to Postmastectomy Radiation Therapy Using Scanned Proton Beams

    Energy Technology Data Exchange (ETDEWEB)

    Depauw, Nicolas, E-mail: ndepauw@partners.org [Francis H. Burr Proton Therapy Center, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Centre for Medical Radiation Physics, University of Wollongong, New South Wales (Australia); Batin, Estelle; Daartz, Julianne [Francis H. Burr Proton Therapy Center, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Rosenfeld, Anatoly [Centre for Medical Radiation Physics, University of Wollongong, New South Wales (Australia); Adams, Judith; Kooy, Hanne; MacDonald, Shannon; Lu, Hsiao-Ming [Francis H. Burr Proton Therapy Center, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2015-02-01

    Purpose: Postmastectomy radiation therapy (PMRT), currently offered at Massachusetts General Hospital, uses proton pencil beam scanning (PBS) with intensity modulation, achieving complete target coverage of the chest wall and all nodal regions and reduced dose to the cardiac structures. This work presents the current methodology for such treatment and the ongoing effort for its improvements. Methods and Materials: A single PBS field is optimized to ensure appropriate target coverage and heart/lung sparing, using an in–house-developed proton planning system with the capability of multicriteria optimization. The dose to the chest wall skin is controlled as a separate objective in the optimization. Surface imaging is used for setup because it is a suitable surrogate for superficial target volumes. In order to minimize the effect of beam range uncertainties, the relative proton stopping power ratio of the material in breast implants was determined through separate measurements. Phantom measurements were also made to validate the accuracy of skin dose calculation in the treatment planning system. Additionally, the treatment planning robustness was evaluated relative to setup perturbations and patient breathing motion. Results: PBS PMRT planning resulted in appropriate target coverage and organ sparing, comparable to treatments by passive scattering (PS) beams but much improved in nodal coverage and cardiac sparing compared to conventional treatments by photon/electron beams. The overall treatment time was much shorter than PS and also shorter than conventional photon/electron treatment. The accuracy of the skin dose calculation by the planning system was within ±2%. The treatment was shown to be adequately robust relative to both setup uncertainties and patient breathing motion, resulting in clinically satisfying dose distributions. Conclusions: More than 25 PMRT patients have been successfully treated at Massachusetts General Hospital by using single-PBS fields

  7. Radiation retinopathy after external-beam irradiation: Analysis of time-dose factors

    International Nuclear Information System (INIS)

    To investigate the risk of radiation-induced retinopathy according to total radiation dose and fraction size, based on both retorspective and prospectively collected data. Between October 1964 and May 1989, 68 retinae in 64 patients received fractionated external-beam irradiation during the treatment of primary extracranial head and neck tumors. All patients had a minimum of 3 years of ophthalmologic follow-up (range, 3 to 26 years; mean, 9 years; median, 8 years). Twenty-seven eyes in 26 patients developed radiation retinopathy resulting in visual acuity of 20/200 or worse. The mean and median times to the onset of symptoms attributable to retinal ischemia were 2.8 and 2.5 years, respectively. Fourteen of the injured eyes developed rubeosis iridis and/or neovascular glaucoma. Radiation retinopathy was not observed at doses below 45 Gy, but increased steadily in incidence at doses ≥45Gy. In the range of doses between 45 and 55 Gy, there was an increased risk of injury among patients who received doses per fraction of ≥1.9Gy (p - .09). There was also a trend toward increased risk of injury among patients who received chemotherapy (two of two vs. four of ten in the 45-51 Gy range; p - .23). The lowest dose associated with retinopathy was 45 Gy delivered to a diabetic patient by twice-a-day fractionation. The data did not suggest an increased risk of radiation retinopathy with increasing age. The current study suggests the importance of total dose as well as dose per fraction, and adds support to a small body of literature suggesting that patients with diabetes mellitus or who receive chemotherapy are at increased risk of injury. A sigmoid dose-response curve is constructed from our current data and data from the literature. 36 refs., 5 figs., 4 tabs

  8. Equivalent Biochemical Control and Improved Prostate-Specific Antigen Nadir After Permanent Prostate Seed Implant Brachytherapy Versus High-Dose Three-Dimensional Conformal Radiotherapy and High-Dose Conformal Proton Beam Radiotherapy Boost

    International Nuclear Information System (INIS)

    Purpose: Permanent prostate implant brachytherapy (PPI), three-dimensional conformal radiotherapy (3D-CRT), and conformal proton beam radiotherapy (CPBRT) are used in the treatment of localized prostate cancer, although no head-to-head trials have compared these modalities. We studied the biochemical control (biochemical no evidence of disease [bNED]) and prostate-specific antigen (PSA) nadir achieved with contemporary PPI, and evaluated it against 3D-CRT and CPBRT. Patients and Methods: A total of 249 patients were treated with PPI at the University of California, San Francisco, and the outcomes were compared with those from a 3D-CRT cohort and the published results of a high-dose CPBRT boost (CPBRTB) trial. For each comparison, subsets of the PPI cohort were selected with patient and disease criteria similar to those of the reference group. Results: With a median follow-up of 5.3 years, the bNED rate at 5 and 7 years achieved with PPI was 92% and 86%, respectively, using the American Society for Therapeutic Radiology and Oncology (ASTRO) definition, and 93% using the PSA nadir plus 2 ng/mL definition. Using the ASTRO definition, a 5-year bNED rate of 78% was achieved for the 3D-CRT patients compared with 94% for a comparable PPI subset and 93% vs. 92%, respectively, using the PSA nadir plus 2 ng/mL definition. The median PSA nadir for patients treated with PPI and 3D-CRT was 0.10 and 0.40 ng/mL, respectively (p < .0001). For the CPBRT comparison, the 5-year bNED rate after a CPBRTB was 91% using the ASTRO definition vs. 93% for a similar group of PPI patients. A greater proportion of PPI patients achieved a lower PSA nadir compared with those achieved in the CPBRTB trial (PSA nadir ≤0.5 ng/mL, 91% vs. 59%, respectively). Conclusion: We have demonstrated excellent outcomes in low- to intermediate-risk patients treated with PPI, suggesting at least equivalent 5-year bNED rates and a greater proportion of men achieving lower PSA nadirs compared with 3D-CRT or

  9. Design concept for a direct water-cooled silicon crystal for use in a high-power synchrotron radiation beam

    International Nuclear Information System (INIS)

    The onset of high-power Synchrotron Radiation beams, now available at several of the Synchrotron Radiation facilities, has resulted in a search for new ways on how to handle the increased thermal load on optical components that are directly exposed to these beams. This report examines one possible way of the direct water-cooling of a silicon crystal as used in monochromators and how to get the water to the crystal with the least possible strain on the crystal. Suggestions are made on how to mount the crystal assembly in an experimental setup, so that physical properties of the crystal can be measured during direct exposure to a suitable high-power Synchrotron Radiation beam. Ways of making small correction movements to the crystal in two directions are outlined. (author)

  10. Whole acute toxicity removal from industrial and domestic effluents treated by electron beam radiation: emphasis on anionic surfactants

    International Nuclear Information System (INIS)

    Electron beam radiation has been applied to improve real industrial and domestic effluents received by Suzano wastewater treatment plant. Radiation efficacy has been evaluated as toxicity reduction, using two biological assays. Three sites were sampled and submitted for toxicity assays, anionic surfactant determination and electron beam irradiation. This paper shows the reduction of acute toxicity for both test-organisms, the marine bacteria Vibrio fischeri and the crustacean Daphnia similis. The raw toxic effluents exibitted from 0.6 ppm up to 11.67 ppm for anionic surfactant before being treated by the electron beam. Radiation processing resulted in reduction of the acute toxicity as well as surfactant removal. The final biological effluent was in general less toxic than other sites but the presence of anionic surfactants was evidenced

  11. Whole acute toxicity removal from industrial and domestic effluents treated by electron beam radiation: emphasis on anionic surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, M.C.F. E-mail: mariacristinafm@uol.com.br; Romanelli, M.F; Sena, H.C.; Pasqualini da Silva, G.; Sampa, M.H.O.; Borrely, S.I

    2004-10-01

    Electron beam radiation has been applied to improve real industrial and domestic effluents received by Suzano wastewater treatment plant. Radiation efficacy has been evaluated as toxicity reduction, using two biological assays. Three sites were sampled and submitted for toxicity assays, anionic surfactant determination and electron beam irradiation. This paper shows the reduction of acute toxicity for both test-organisms, the marine bacteria Vibrio fischeri and the crustacean Daphnia similis. The raw toxic effluents exibitted from 0.6 ppm up to 11.67 ppm for anionic surfactant before being treated by the electron beam. Radiation processing resulted in reduction of the acute toxicity as well as surfactant removal. The final biological effluent was in general less toxic than other sites but the presence of anionic surfactants was evidenced.

  12. Whole acute toxicity removal from industrial and domestic effluents treated by electron beam radiation: emphasis on anionic surfactants

    Science.gov (United States)

    Moraes, M. C. F.; Romanelli, M. F.; Sena, H. C.; Pasqualini da Silva, G.; Sampa, M. H. O.; Borrely, S. I.

    2004-09-01

    Electron beam radiation has been applied to improve real industrial and domestic effluents received by Suzano wastewater treatment plant. Radiation efficacy has been evaluated as toxicity reduction, using two biological assays. Three sites were sampled and submitted for toxicity assays, anionic surfactant determination and electron beam irradiation. This paper shows the reduction of acute toxicity for both test-organisms, the marine bacteria Vibrio fischeri and the crustacean Daphnia similis. The raw toxic effluents exibitted from 0.6 ppm up to 11.67 ppm for anionic surfactant before being treated by the electron beam. Radiation processing resulted in reduction of the acute toxicity as well as surfactant removal. The final biological effluent was in general less toxic than other sites but the presence of anionic surfactants was evidenced.

  13. Phase I/II study of preoperative chemo-radiotherapy (CT-RT) using twice daily radiation as concomitant boost during two cycles of taxol (T), cisplatin (C), 5-FU (F) in esophageal cancer: normal tissue tolerance and early results

    International Nuclear Information System (INIS)

    /m2. Absolute neutrophile and platelet counts at nadir were 1,369/μl and 115,000/μl, and 1,035/μl and 81,000/μl for the first and second cycles of CT respectively. Grade (3(4)) esophagitis which was observed in 60% of pts was managed effectively with nutritional support. Thirty two of 38 pts (excluding 4 pts with new metastatic disease, 1 septic death, 1 death from hemorrhage in brain) were subjected to surgery and able to undergo complete resection (84%). Operative mortality was 6% ((2(32))) and overall treatment related mortality was 11% ((4(38))). Tumor downstaging and pathologic complete remission were obtained in 66% ((21(32))) and 38% ((12(32))) of pts respectively. Thirty of 38 pts (79%) remain free of relapse and median survival time has not reached. Conclusion: The concurrent CT (PFT regimen)-RT with the intensified RT dose schedule by concomitant boost seems an effective treatment with acceptable toxicity at the level of Taxol dose 100 mg/m2. Potential impact on survival of 66% rate of tumor downstaging and 38% rate of pathologic CR remains to be evaluated. Concomitant boost RT as a means of intensifying RT and exploiting chemo-radiation interaction in CT-RT deserves further study

  14. Multiscale registration of planning CT and daily cone beam CT images for adaptive radiation therapy

    International Nuclear Information System (INIS)

    Adaptive radiation therapy (ART) is the incorporation of daily images in the radiotherapy treatment process so that the treatment plan can be evaluated and modified to maximize the amount of radiation dose to the tumor while minimizing the amount of radiation delivered to healthy tissue. Registration of planning images with daily images is thus an important component of ART. In this article, the authors report their research on multiscale registration of planning computed tomography (CT) images with daily cone beam CT (CBCT) images. The multiscale algorithm is based on the hierarchical multiscale image decomposition of E. Tadmor, S. Nezzar, and L. Vese [Multiscale Model. Simul. 2(4), pp. 554-579 (2004)]. Registration is achieved by decomposing the images to be registered into a series of scales using the (BV, L2) decomposition and initially registering the coarsest scales of the image using a landmark-based registration algorithm. The resulting transformation is then used as a starting point to deformably register the next coarse scales with one another. This procedure is iterated at each stage using the transformation computed by the previous scale registration as the starting point for the current registration. The authors present the results of studies of rectum, head-neck, and prostate CT-CBCT registration, and validate their registration method quantitatively using synthetic results in which the exact transformations our known, and qualitatively using clinical deformations in which the exact results are not known.

  15. A study on size effect of carboxymethyl starch nanogel crosslinked by electron beam radiation

    Science.gov (United States)

    Binh, Doan; Pham Thi Thu Hong; Nguyen Ngoc Duy; Nguyen Thanh Duoc; Nguyen Nguyet Dieu

    2012-07-01

    The formation of carboxymethyl starch (CMS) nanogel with 50 nm less particle size was carried out through a radiation crosslinked process on the electron beam (EB) linear accelerator. Changes of intrinsic viscosities and weight averaged molecular weight in the CMS concentration, which ranged from 3 to 10 mg ml-1 in absorbed doses were investigated. There were some new peaks in the 1H NMR spectra of CMS nanogel compared with those of CMS polymer. These results were anticipated that the predominant intramolecular crosslinking of dilute CMS aqueous solution occurred while being exposed to a short intense pulse of ionizing radiation. Hydrodynamic radius (often called particle size, Rh) and distribution of particle size were measured by a dynamic light scattering technique. The radiation yield of intermolecular crosslinking of CMS solution was calculated from the expression of Gx (Charlesby, 1960; Jung-Chul, 2010). The influence of the "size effect" was demonstrated by testing culture of Lactobacillus bacteria on MRS agar culture medium containing CMS nanogel and polymer. Results showed that the number of Lactobacillus bacteria growing on nanogel containing culture medium is about 170 cfu/ml and on polymer containing culture medium is only 6 cfu/ml.

  16. Influence of radiation temperature on the crosslinking of nitrile rubber by electron beam irradiation

    International Nuclear Information System (INIS)

    Nitrile rubber with 18% acrylonitrile content in presence and absence of polyfunctional monomers like trimethylolpropane triacrylate (TMPTA), tripropyleneglycol diacrylate (TPGDA), tetramethylolmethane tetraacrylate (TMMT) and m-phenylene bismaleimide was subjected to electron beam irradiations at different temperatures. The structural changes with different doses of radiations were investigated with the help of FTIR spectroscopy (in the ATR mode), dynamic mechanical thermal analysis and sol-gel analysis. There was a decrease in the concentration of olefinic groups for this elastomer on radiation at high temperature as compared to the room temperature. The increase in crosslinking at elevated temperature was also revealed by the increase in % gel content and dynamic storage moduli with radiation dose. The lifetime of spurs, an important criterion for overlapping of spurs, was determined for both grafted and ungrafted nitrile rubber using a mathematical model. The ratio of scissioning to crosslinking for nitrile rubber was determined using Charlesby-Pinner equation. The mechanical properties were studied and the tensile strength was found to increase with grafting of polyfunctional monomers on irradiation at high temperature

  17. Comparison of γ-radiation and electron beam irradiation effects on gelatin

    International Nuclear Information System (INIS)

    Gelatin is a heterogeneous mixture of water-soluble proteins of high average molecular weight derived by hydrolytic action from collagen, a protein of mammal external protective tissues. There are many characteristics of a material that can indicate its quality or performance in its intended use. The knowledge of a material's rheological characteristics is valuable to predict its pourability, its performance in a dipping or coating operation or the ease with which it may be handled, processed or used. In this work bovine powder gelatin was submitted to γ-radiation from a 60Co source, dose rate about 7 kGy/h and to electron beam irradiation, dose rate about 11 kGy/s. The doses applied were 5, 10, 20 and 50 kGy. The radiation effects were measured following viscosity changes at 40 deg. C of gelatin powder 10% aqueous solutions. The relationship between the decrease in viscosity of gelatin solutions and radiation dose presented close comparable values for both irradiation processes

  18. Disinfection and reduction of organic load of sewage water by electron beam radiation

    Science.gov (United States)

    Maruthi, Y. Avasn; Das, N. Lakshmana; Hossain, Kaizar; Sarma, K. S. S.; Rawat, K. P.; Sabharwal, S.

    2011-09-01

    The efficacy of electron beam radiation for the disinfection and reduction of organic load of sewage water was assessed with ILU-6 Accelerator at Radiation Technology Development Division of the Bhabha Atomic Research Centre, Mumbai India. The current problem on environmental health in relation to water pollution insists for the safe disposal of sewage water. In general, sewage water comprises heterogeneous organic based chemicals as well as pathogens. EB treatment of the wastewater has found to be very effective in reducing the pathogens as well as organic load. EB dose of 1.5 kGy was sufficient for complete elimination of total coli forms. The experimental results elucidated the reduction of biological oxygen demand—BOD (35 and 51.7%) in both inlet and outlet sewage samples. Similarly reduction of chemical oxygen demand—COD was observed (37.54 and 52.32%) in both sewage samples with respect to increase in irradiation doses (0.45-6 kGy). The present study demonstrated the potential of ionizing radiation for disinfection of sewage and to increase the water quality of the wastewater by decreasing BOD and COD. So, the irradiation sewage water can find its application either in agriculture for irrigation, in industry for cooling purpose and some selected domestic purposes.

  19. Effect of radiation by electron beam on the mechanical properties of high density polyethylene

    International Nuclear Information System (INIS)

    In this work, the high density polyethylene (HDPE) was submitted to radiation doses ranging from 150 to 250 kGy in a 1.5 MeV electron accelerator, with purpose to evaluate the radiation dose effects on his mechanical properties. The irradiations were accomplished at 14 kGy/s dose, room temperature and presence of air. The material mechanical properties changes due to the irradiation were evaluated by means of traction and flexure resistance tests. The results presented a gain up to 150 % in the original rupture traction of the HDPE (not irradiated samples, gain up to 10 % in the percentage of maximum elongation in rupture for the irradiated samples, except for the 250 kGy, where no significant changes were observed (p < 0.05). The results also presented gains up to 20 % in the flexure resistance and losses of the order of 3 to 4 % in the traction resistance in the HDPE drainage related to the original, for the studied radiation dose interval (p <0.05). These results indicate that the irradiation by electron beam, at the conditions studied in this work, is a adequate d process for the modification of the HDPE mechanical properties, mainly for those applications requiring a high resistance to the traction solicitations

  20. Phase I-II study of hypofractionated simultaneous integrated boost using volumetric modulated arc therapy for adjuvant radiation therapy in breast cancer patients: a report of feasibility and early toxicity results in the first 50 treatments

    International Nuclear Information System (INIS)

    To report results in terms of feasibility and early toxicity of hypofractionated simultaneous integrated boost (SIB) approach with Volumetric Modulated Arc Therapy (VMAT) as adjuvant treatment after breast-conserving surgery. Between September 2010 and May 2011, 50 consecutive patients presenting early-stage breast cancer were submitted to adjuvant radiotherapy with SIB-VMAT approach using RapidArc in our Institution (Istituto Clinico Humanitas ICH). Three out of 50 patients were irradiated bilaterally (53 tumours in 50 patients). All patients were enrolled in a phase I-II trial approved by the ICH ethical committee. All 50 patients enrolled in the study underwent VMAT-SIB technique to irradiate the whole breast with concomitant boost irradiation of the tumor bed. Doses to whole breast and surgical bed were 40.5 Gy and 48 Gy respectively, delivered in 15 fractions over 3 weeks. Skin toxicities were recorded during and after treatment according to RTOG acute radiation morbidity scoring criteria with a median follow-up of 12 months (range 8–16). Cosmetic outcomes were assessed as excellent/good or fair/poor. The median age of the population was 68 years (range 36–88). According to AJCC staging system, 38 breast lesions were classified as pT1, and 15 as pT2; 49 cases were assessed as N0 and 4 as N1. The maximum acute skin toxicity by the end of treatment was Grade 0 in 20/50 patients, Grade 1 in 32/50, Grade 2 in 0 and Grade 3 in 1/50 (one of the 3 cases of bilateral breast irradiation). No Grade 4 toxicities were observed. All Grade 1 toxicities had resolved within 3 weeks. No significant differences in cosmetic scores on baseline assessment vs. 3 months and 6 months after the treatment were observed: all patients were scored as excellent/good (50/50) compared with baseline; no fair/poor judgment was recorded. No other toxicities or local failures were recorded during follow-up. The 3-week course of postoperative radiation using VMAT with SIB showed to be

  1. A novel diamond-based beam position monitoring system for the High Radiation to Materials facility at CERN SPS

    CERN Document Server

    AUTHOR|(CDS)2092886; Höglund, Carina

    The High Radiation to Materials facility employs a high intensity pulsed beam imposing several challenges on the beam position monitors. Diamond has been shown to be a resilient material with its radiation hardness and mechanical strength, while it is also simple due to its wide bandgap removing the need for doping. A new type of diamond based beam position monitor has been constructed, which includes a hole in the center of the diamond where the majority of the beam is intended to pass through. This increases the longevity of the detectors as well as allowing them to be used for high intensity beams. The purpose of this thesis is to evaluate the performance of the detectors in the High Radiation to Materials facility for various beam parameters, involving differences in position, size, bunch intensity and bunch number. A prestudy consisting of calibration of the detectors using single incident particles is also presented. The detectors are shown to work as intended after a recalibration of the algorithm, alb...

  2. Prospective study of special stage II (T 2b-3 N 0 M 0 non-small-cell lung cancer treated with hypofractionated-simultaneous integrated boost-intensity modulated radiation therapy

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2015-01-01

    Full Text Available Purpose: To analyze the effects of hypofractionated-simultaneous integrated boost-intensity modulated radiation therapy (Hypo-SIB-IMRT on medically inoperable patients with special stage II (T 2b-3 N 0 M 0 non-smallcell lung cancer (NSCLC. Materials and Methods: Twenty-eight qualified patients were included. Hypo-SIB-IMRT was delivered with internal gross tumor volume (iGTV 75Gy, clinical target volume (CTV 60Gy, and planning target volume (PTV 45Gy on weekdays in 3 weeks. Results: The 1-, 2-, and 3-year overall survivals (OSs were 93, 85, and 61%, respectively, with a median survival of 46.5 months; while progression-free survivals (PFSs were 92, 79, and 64%; and distant metastasis-free survivals (DMFSs were 92, 84, and 77%, respectively. The cancer-specific survivals (CSS were 93, 88, and 74%, and local control (LC were 92, 83, and 74%, respectively. 7.1% (2/28 of patients occurred local pain, 28.6% (8/28 were with Grade 1or 2 radiation pneumonitis (RP, and 7.1% (2/28 with Grade 1 esophagitis. Of the eight patients with RP, 17.9% (5/28 developed Grade 1 radiation pulmonary fibrosis (RPF. Conclusion: Due to the favorable long-term survivals, LC, and minimal toxicities, Hypo-SIB-IMRT presented in this prospective study may be considered an option for patients with special stage II (T 2b-3 N 0 M 0 NSCLC who were medically inoperable.

  3. Construction and performance test of radiation shielding for 300 keV/20 mA electron beam machine

    International Nuclear Information System (INIS)

    The construction and performance test of radiation shielding for 300 keV/20 mA electron beam machine (EBM) has been done. Radiation shielding is used for reduce X-ray radiation which is generated by operation of the EBM, so it is not harmful for people who work in that environment. Radiation shielding plates made of bars of lead (Pb) with a length of 135 cm, 10 cm of width, 2.5 cm of thick and composed a EBM radiation shielding. The plates are made of lead by way of casting and finished mechanically by machine, then installed manually on a frame to form a EBM radiation shielding. In the calculation of thick radiation shield already qualified dose rate limit is set by BAPETEN ≤ 2.5 mrem/hr. The results of the initial test radiation shielding is functioning, it is shown by the results of measurements of the maximum dose rate 0.26 mrem/hr at the operating conditions of EBM with voltage 209 kV and 50 mA of electron beam current. Based on the results test of the construction of radiation shielding are qualified dose rate limit set by BAPETEN. (author)

  4. Optical modulation of electron beam using the opto-semiconductor device on the photocathode RF gun for the radiation therapy

    International Nuclear Information System (INIS)

    The radiation therapy of cancer is developing to un-uniform irradiation, for concentrating dose to a tumor and reducing dose to normal tissue. For the un-uniform irradiation, optical modulation of electron beam using the Digital Micro Mirror Device was studied on a photocathode RF gun. The optical modulation of electron beam and dynamic control succeeded by a digital micro mirror device. Fundamental data such as the spatial resolution and the contrast of the optical modulated electron beam was measured. It will be reported that the relations between the intensity distribution and the emittance. (author)

  5. Time resolved energy measurement of the Tesla test facility beam through the analysis of optical transition radiation angular distribution

    International Nuclear Information System (INIS)

    This study of the energy stability along the macropulse of the Tesla test facility Linac (TTFL) (1) was obtained by the measurement of the angular distribution of the optical transition radiation (OTR). This technique does not require a dispersive section and can be performed at any point of the beam line. Measurements have been performed with different settings of the RF low level control and at different values of the beam current. An energy variation along the macropulse was spread of the whole macrobunch. The analysis of the OTR angular distribution pattern allows also, to some extent, to evaluate the beam angular spread

  6. On the generation of supershort avalanche electron beams and x radiation during nanosecond discharges in dense gases (results and discussion)

    Science.gov (United States)

    Tarasenko, V. F.; Rybka, D. B.; Baksht, E. H.; Kostyrya, I. D.; Lomaev, M. I.

    2007-09-01

    Results of investigations of the generation of subnanosecond runaway electron beams and x radiation in gas diodes at elevated pressures are presented. The energy distributions of runaway electron beams generated in air at atmospheric pressure and the amplitude and duration of beam current pulses downstream of the foil have been measured, and also the mechanism of generation of a runaway electron beam has been analyzed. To record the beam current pulses, a collector which provided ˜50-ps time resolution and a Tektronix TDS6604 real-time oscilloscope were used in the experiment. It has been shown that the new experimental data and model predictions confirm in the main the results earlier obtained at the Institute of High Current Electronics of the Russian Academy of Sciences Siberian Division. Evidence is cited that the key statements of L. P. Babich are erroneous.

  7. Quality control methodology and implementation of X-radiation standards beams, mammography level, following the standard IEC 61267

    International Nuclear Information System (INIS)

    In this work it was developed and applied a quality control program of the X radiation system (160 kV, constant potential, target of tungsten) of the Calibration Laboratory of IPEN(LCI) in the energy range relative to mammography beams (from 25 kV to 35 kV). The X radiation standards beams, level mammography, using molybdenum and aluminum as additional filtration, were established after the application of this quality control program following national and international recommendations. The reference ionization chamber has traceability to PTB and was regularly submitted to quality control tests for evaluation and analysis of its performance. The radiation qualities emerging from the X-radiation assembly (RQR-M), based on a phantom made up of an aluminum added filter (RQA-M), narrow beam condition (RQN-M) and broad beam condition (RQB-M), following the recommendations of the international standard IEC 61267 (2005) and the IAEA code of practice, TRS 457 (2007) were established. For the implantation of RQN-M and RQB-M radiation qualities, two mammography phantoms were developed. The half-value layers found are those presented by the German primary laboratory PTB, and varied from 0.35 to 1.21 mm Al. The air kerma rates were obtained for all the 15 implanted qualities. (author)

  8. Adaptive Radiation Therapy for Postprostatectomy Patients Using Real-Time Electromagnetic Target Motion Tracking During External Beam Radiation Therapy

    International Nuclear Information System (INIS)

    Purpose: Using real-time electromagnetic (EM) transponder tracking data recorded by the Calypso 4D Localization System, we report inter- and intrafractional target motion of the prostate bed, describe a strategy to evaluate treatment adequacy in postprostatectomy patients receiving intensity modulated radiation therapy (IMRT), and propose an adaptive workflow. Methods and Materials: Tracking data recorded by Calypso EM transponders was analyzed for postprostatectomy patients that underwent step-and-shoot IMRT. Rigid target motion parameters during beam delivery were calculated from recorded transponder positions in 16 patients with rigid transponder geometry. The delivered doses to the clinical target volume (CTV) were estimated from the planned dose matrix and the target motion for the first 3, 5, 10, and all fractions. Treatment adequacy was determined by comparing the delivered minimum dose (Dmin) with the planned Dmin to the CTV. Treatments were considered adequate if the delivered CTV Dmin is at least 95% of the planned CTV Dmin. Results: Translational target motion was minimal for all 16 patients (mean: 0.02 cm; range: −0.12 cm to 0.07 cm). Rotational motion was patient-specific, and maximum pitch, yaw, and roll were 12.2, 4.1, and 10.5°, respectively. We observed inadequate treatments in 5 patients. In these treatments, we observed greater target rotations along with large distances between the CTV centroid and transponder centroid. The treatment adequacy from the initial 10 fractions successfully predicted the overall adequacy in 4 of 5 inadequate treatments and 10 of 11 adequate treatments. Conclusion: Target rotational motion could cause underdosage to partial volume of the postprostatectomy targets. Our adaptive treatment strategy is applicable to post-prostatectomy patients receiving IMRT to evaluate and improve radiation therapy delivery

  9. Increasing Use of Dose-Escalated External Beam Radiation Therapy for Men With Nonmetastatic Prostate Cancer

    International Nuclear Information System (INIS)

    Purpose: To examine recent practice patterns, using a large national cancer registry, to understand the extent to which dose-escalated external beam radiation therapy (EBRT) has been incorporated into routine clinical practice for men with prostate cancer. Methods and Materials: We conducted a retrospective observational cohort study using the National Cancer Data Base, a nationwide oncology outcomes database in the United States. We identified 98,755 men diagnosed with nonmetastatic prostate cancer between 2006 and 2011 who received definitive EBRT and classified patients into National Comprehensive Cancer Network (NCCN) risk groups. We defined dose-escalated EBRT as total prescribed dose of ≥75.6 Gy. Using multivariable logistic regression, we examined the association of patient, clinical, and demographic characteristics with the use of dose-escalated EBRT. Results: Overall, 81.6% of men received dose-escalated EBRT during the study period. The use of dose-escalated EBRT did not vary substantially by NCCN risk group. Use of dose-escalated EBRT increased from 70.7% of patients receiving treatment in 2006 to 89.8% of patients receiving treatment in 2011. On multivariable analysis, year of diagnosis and use of intensity modulated radiation therapy were significantly associated with receipt of dose-escalated EBRT. Conclusions: Our study results indicate that dose-escalated EBRT has been widely adopted by radiation oncologists treating prostate cancer in the United States. The proportion of patients receiving dose-escalated EBRT increased nearly 20% between 2006 and 2011. We observed high utilization rates of dose-escalated EBRT within all disease risk groups. Adoption of intensity modulated radiation therapy was strongly associated with use of dose-escalated treatment

  10. RADIATION THERAPY QUALITY IN CCG/POG INTERGROUP 9961: IMPLICATIONS FOR CRANIOSPINAL IRRADIATION AND THE POSTERIOR FOSSA BOOST IN FUTURE MEDULLOBLASTOMA TRIALS

    OpenAIRE

    BernadineDonahue; MaryAnneH.Marymont; SandraKessel; EmikoHolmes; MehmetKocak; RogerJ.Packer

    2012-01-01

    Purpose: Associations of radiation therapy (RT) deviations and outcomes in medulloblastoma have not been defined well, particularly in the era of reduced-dose craniospinal irradiation and chemotherapy. The aim of this study is to evaluate the quality of RT on Children’s Cancer Group/Pediatric Oncology Group 9961 and analyze associations of RT deviations with outcome. Materials and Methods: Major volume deviations were assessed based on the distance from specified anatomical region to field ed...

  11. Boost C++ application development cookbook

    CERN Document Server

    Polukhin, Antony

    2013-01-01

    This book follows a cookbook approach, with detailed and practical recipes that use Boost libraries.This book is great for developers new to Boost, and who are looking to improve their knowledge of Boost and see some undocumented details or tricks. It's assumed that you will have some experience in C++ already, as well being familiar with the basics of STL. A few chapters will require some previous knowledge of multithreading and networking. You are expected to have at least one good C++ compiler and compiled version of Boost (1.53.0 or later is recommended), which will be used during the exer

  12. Gradient boosting machines, a tutorial.

    Science.gov (United States)

    Natekin, Alexey; Knoll, Alois

    2013-01-01

    Gradient boosting machines are a family of powerful machine-learning techniques that have shown considerable success in a wide range of practical applications. They are highly customizable to the particular needs of the application, like being learned with respect to different loss functions. This article gives a tutorial introduction into the methodology of gradient boosting methods with a strong focus on machine learning aspects of modeling. A theoretical information is complemented with descriptive examples and illustrations which cover all the stages of the gradient boosting model design. Considerations on handling the model complexity are discussed. Three practical examples of gradient boosting applications are presented and comprehensively analyzed. PMID:24409142

  13. Gradient Boosting Machines, A Tutorial

    Directory of Open Access Journals (Sweden)

    Alexey eNatekin

    2013-12-01