1
|
Olasupo A, Corbin DR, Shiflett MB. Trends in low temperature and non-thermal technologies for the degradation of persistent organic pollutants. J Hazard Mater 2024; 468:133830. [PMID: 38387180 DOI: 10.1016/j.jhazmat.2024.133830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 02/07/2024] [Accepted: 02/16/2024] [Indexed: 02/24/2024]
Abstract
The daunting effects of persistent organic pollutants on humans, animals, and the environment cannot be overemphasized. Their fate, persistence, long-range transport, and bioavailability have made them an environmental stressor of concern which has attracted the interest of the research community. Concerted efforts have been made by relevant organizations utilizing legislative laws to ban their production and get rid of them completely for the sake of public health. However, they have remained refractive in different compartments of the environment. Their bioavailability is majorly a function of different anthropogenic activities. Landfilling and incineration are among the earliest classical means of environmental remediation of waste; however, they are not sustainable due to the seepage of contaminants in landfills, the release of toxic gases into the atmosphere and energy requirements during incineration. Other advanced waste destruction technologies have been explored for the degradation of these recalcitrant pollutants; although, some are efficient, but are limited by high amounts of energy consumption, the use of organic solvents and hazardous chemicals, high capital and operational cost, and lack of public trust. Thus, this study has systematically reviewed different contaminant degradation technologies, their efficiency, and feasibility. Finally, based on techno-economic feasibility, non-invasiveness, efficiency, and environmental friendliness; radiation technology can be considered a viable alternative for the environmental remediation of contaminants in all environmental matrices at bench-, pilot-, and industrial-scale.
Collapse
Affiliation(s)
- Ayo Olasupo
- Institute for Sustainable Engineering, 1536 W. 15th Street, Lawrence, Kansas 66045, United States; Department of Chemical and Petroleum Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, Kansas, 66045, United States
| | - David R Corbin
- Institute for Sustainable Engineering, 1536 W. 15th Street, Lawrence, Kansas 66045, United States; Department of Chemical and Petroleum Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, Kansas, 66045, United States
| | - Mark B Shiflett
- Institute for Sustainable Engineering, 1536 W. 15th Street, Lawrence, Kansas 66045, United States; Department of Chemical and Petroleum Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, Kansas, 66045, United States.
| |
Collapse
|
2
|
Iliaskou C, Rossi G, Sachpazidis I, Boronikolas V, Gainey M, Baltas D. Evaluation of RADIANCE Monte Carlo algorithm for treatment planning in electron based Intraoperative Radiotherapy (IOERT). Z Med Phys 2024:S0939-3889(23)00149-6. [PMID: 38182457 DOI: 10.1016/j.zemedi.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 01/07/2024]
Abstract
PURPOSE To perform experimental as well as independent Monte Carlo (MC) evaluation of the MC algorithm implemented in RADIANCE version 4.0.8, a dedicated treatment planning system (TPS) for 3D electron dose calculations in intraoperative radiation therapy (IOERT). METHODS AND MATERIALS The MOBETRON 2000 (IntraOp Medical Corporation, Sunnyvale, CA) IOERT accelerator was employed. PDD and profiles for five cylindrical plastic applicators with 50-90 mm diameter and 0°, 30° beveling were measured in a water phantom, at nominal energies of 6, 9 and 12 MeV. Additional PDD measurements were performed for all the energies without applicator. MC modeling of the MOBETRON was performed with the user code BEAMnrc and egs_chamber of the MC simulation toolkit EGSnrc. The generated phase space files of the two 0°-bevel applicators (50 mm, 80 mm) and three energies in both RADIANCE and BEAMnrc, were used to determine PDD and profiles in various set-ups of virtual water phantoms with air and bone inhomogeneities. 3D dose distributions were also calculated in image data sets of an anthropomorphic tissue-equivalent pelvis phantom. Image acquisitions were realized with a CT scanner (Philips Big Bore CT, Netherlands). Gamma analysis was applied to quantify the deviations of the RADIANCE calculations to the measurements and EGSnrc calculations. Gamma criteria normalized to the global maximum were investigated between 2%, 2 mm and 3%, 3 mm. RESULTS RADIANCE MC calculations satisfied the gamma criteria of 3%, 3 mm with a tolerance limit of 85% passing rate compared to in- water phantom measurements, except for the dose profiles of the 30° beveled applicators. Mismatches lay in surface doses, in umbra regions and in the beveled end of the 30° applicators. A very good agreement to the EGSnrc calculations in heterogeneous media was observed. Deviations were more pronounced for the larger applicator diameter and higher electron energy. In 3D dose comparisons in the anthropomorphic phantom, gamma passing rates were higher than 96 % for both simulated applicators. CONCLUSIONS RADIANCE MC algorithm agrees within 3%, 3 mm criteria with in-water phantom measurements and EGSnrc MC dose distributions in heterogeneous media for 0°-bevel applicators. The user should be aware of missing scattering components and the 30° beveled applicators should be used with attention.
Collapse
Affiliation(s)
- Charoula Iliaskou
- Division of Medical Physics, Department of Radiation Oncology, University Medical Center, Freiburg 79106, Germany; German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany.
| | - Giulio Rossi
- Division of Medical Physics, Department of Radiation Oncology, University Medical Center, Freiburg 79106, Germany; German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Ilias Sachpazidis
- Division of Medical Physics, Department of Radiation Oncology, University Medical Center, Freiburg 79106, Germany; German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Vasilios Boronikolas
- Division of Medical Physics, Department of Radiation Oncology, University Medical Center, Freiburg 79106, Germany; German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Mark Gainey
- Division of Medical Physics, Department of Radiation Oncology, University Medical Center, Freiburg 79106, Germany; German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Dimos Baltas
- Division of Medical Physics, Department of Radiation Oncology, University Medical Center, Freiburg 79106, Germany; German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| |
Collapse
|
3
|
Calvo Manuel FÁ, Serrano J, Solé C, Cambeiro M, Palma J, Aristu J, Garcia-Sabrido JL, Cuesta MA, Del Valle E, Lapuente F, Miñana B, Morcillo MÁ, Asencio JM, Pascau J. Clinical feasibility of combining intraoperative electron radiation therapy with minimally invasive surgery: a potential for electron-FLASH clinical development. Clin Transl Oncol 2023; 25:429-439. [PMID: 36169803 PMCID: PMC9873754 DOI: 10.1007/s12094-022-02955-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 09/14/2022] [Indexed: 01/28/2023]
Abstract
BACKGROUND Local cancer therapy by combining real-time surgical exploration and resection with delivery of a single dose of high-energy electron irradiation entails a very precise and effective local therapeutic approach. Integrating the benefits from minimally invasive surgical techniques with the very precise delivery of intraoperative electron irradiation results in an efficient combined modality therapy. METHODS Patients with locally advanced disease, who are candidates for laparoscopic and/or thoracoscopic surgery, received an integrated multimodal management. Preoperative treatment included induction chemotherapy and/or chemoradiation, followed by laparoscopic surgery and intraoperative electron radiation therapy. RESULTS In a period of 5 consecutive years, 125 rectal cancer patients were treated, of which 35% underwent a laparoscopic approach. We found no differences in cancer outcomes and tolerance between the open and laparoscopic groups. Two esophageal cancer patients were treated with IOeRT during thoracoscopic resection, with the resection specimens showing intense downstaging effects. Two oligo-recurrent prostatic cancer patients (isolated nodal progression) had a robotic-assisted surgical resection and post-lymphadenectomy electron boost on the vascular and lateral pelvic wall. CONCLUSIONS Minimally invasive and robotic-assisted surgery is feasible to combine with intraoperative electron radiation therapy and offers a new model explored with electron-FLASH beams.
Collapse
Affiliation(s)
| | - Javier Serrano
- Department of Oncology, Clinica Universidad de Navarra, Madrid-Pamplona, Spain
| | - Claudio Solé
- Instituto RadioMedicina, Santiago del Chile, Chile
| | - Mauricio Cambeiro
- Department of Oncology, Clinica Universidad de Navarra, Madrid-Pamplona, Spain
| | - Jacobo Palma
- Department of Oncology, Clinica Universidad de Navarra, Madrid-Pamplona, Spain
| | - Javier Aristu
- Department of Oncology, Clinica Universidad de Navarra, Madrid-Pamplona, Spain
| | | | | | | | - Fernando Lapuente
- Department of Surgery, Clinica Universidad de Navarra, Madrid, Spain
| | - Bernardino Miñana
- Department of Urology, Clinica Universidad de Navarra, Madrid, Spain
| | | | | | - Javier Pascau
- Department of Bioengineering and Aerospace Engineering, Universidad Carlos III de Madrid, Getafe, Spain
| |
Collapse
|
4
|
Rahman M, Trigilio A, Franciosini G, Moeckli R, Zhang R, Böhlen TT. FLASH radiotherapy treatment planning and models for electron beams. Radiother Oncol 2022; 175:210-221. [PMID: 35964763 DOI: 10.1016/j.radonc.2022.08.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 08/04/2022] [Accepted: 08/04/2022] [Indexed: 12/18/2022]
Abstract
The FLASH effect designates normal tissue sparing at ultra-high dose rate (UHDR, >40 Gy/s) compared to conventional dose rate (∼0.1 Gy/s) irradiation while maintaining tumour control and has the potential to improve the therapeutic ratio of radiotherapy (RT). UHDR high-energy electron (HEE, 4-20 MeV) beams are currently a mainstay for investigating the clinical potential of FLASH RT for superficial tumours. In the future very-high energy electron (VHEE, 50-250 MeV) UHDR beams may be used to treat deep-seated tumours. UHDR HEE treatment planning focused at its initial stage on accurate dosimetric modelling of converted and dedicated UHDR electron RT devices for the clinical transfer of FLASH RT. VHEE treatment planning demonstrated promising dosimetric performance compared to clinical photon RT techniques in silico and was used to evaluate and optimise the design of novel VHEE RT devices. Multiple metrics and models have been proposed for a quantitative description of the FLASH effect in treatment planning, but an improved experimental characterization and understanding of the FLASH effect is needed to allow for an accurate and validated modelling of the effect in treatment planning. The importance of treatment planning for electron FLASH RT will augment as the field moves forward to treat more complex clinical indications and target sites. In this review, TPS developments in HEE and VHEE are presented considering beam models, characteristics, and future FLASH applications.
Collapse
Affiliation(s)
- Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Antonio Trigilio
- Physics Department, "La Sapienza" University of Rome, Rome, Italy; INFN National Institute of Nuclear Physics, Rome Section, Rome, Italy
| | - Gaia Franciosini
- Physics Department, "La Sapienza" University of Rome, Rome, Italy; INFN National Institute of Nuclear Physics, Rome Section, Rome, Italy
| | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland.
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA; Dartmouth Hitchcock Medical Center, Lebanon, NH, USA
| | - Till Tobias Böhlen
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| |
Collapse
|
5
|
de la Vega JM, Ruiz-Arrebola S, Tornero-López AM, Vilches M, Guerrero R, Guirado D, Lallena AM. A method to relate StarTrack(®) measurements to R50 variations in clinical linacs. Phys Med 2014; 30:827-32. [PMID: 24735905 DOI: 10.1016/j.ejmp.2014.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 03/18/2014] [Accepted: 03/19/2014] [Indexed: 11/16/2022] Open
Abstract
The relation between the data recorded with any device for the daily checking of the behavior of a clinical linac and the reference magnitudes to be monitored may be unknown. An experimental method relating the energy stability of the electron beam measured with StarTrack(®) to the R50 beam quality index is proposed. The bending magnet current is varied producing a change in the exit energy window and, therefore, a modification of the R50 value. For different values of this current, the output data of StarTrack(®) and the R50, obtained from depth doses measured in a water phantom are determined. A linear fit between both sets of data allows the identification of the StarTrack(®) output that provides the best way to obtain the quality index R50, for each beam nominal energy. Using these fits, an historical datum series is used to analyze the method proposed in the daily quality control. The ouput data of the StarTrack(®) and the R50 values show a good linear correlation. It is possible to establish a methodology that allows the monitoring of R50 by direct use of the daily quality control data measured with StarTrack(®). A method to monitor R50 in the daily quality control using the StarTrack(®) device has been developed. The method may be applied to similar devices in which the statistical control variable does not show a linear behavior with R50.
Collapse
Affiliation(s)
- J M de la Vega
- Servicio de Radiofísica, Hosp. Univ. "San Cecilio", Avda Dr. Olóriz, 16, E-18012 Granada, Spain.
| | - S Ruiz-Arrebola
- Departamento de Oncología Radioterápica, Clínica Santa María, Avda Santa María, 0500, 7520378 Santiago de Chile, Chile
| | - A M Tornero-López
- Servicio de Radiofísica, Hosp. Univ. "San Cecilio", Avda Dr. Olóriz, 16, E-18012 Granada, Spain
| | - M Vilches
- Unidad de Radiofísica, IMOMA (Instituto de Medicina Oncológica y Molecular de Asturias), Avda Richard Gangrio, s/n, E-33193 Oviedo, Spain
| | - R Guerrero
- Servicio de Radiofísica, Hosp. Univ. "San Cecilio", Avda Dr. Olóriz, 16, E-18012 Granada, Spain
| | - D Guirado
- Servicio de Radiofísica, Hosp. Univ. "San Cecilio", Avda Dr. Olóriz, 16, E-18012 Granada, Spain
| | - A M Lallena
- Departamento de Física Atómica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada, Spain
| |
Collapse
|
6
|
Papaconstadopoulos P, Seuntjens J. Sci-Thur AM: Planning - 07: A fast and accurate source model for energy and intensity modulated electron beams. Med Phys 2012; 39:4620. [PMID: 28516524 DOI: 10.1118/1.4740092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The purpose of this study is to develop a highly accurate and fast method for calculating electron beam dose distributions in Modulated Electron Radiation Therapy (MERT). An algorithm has been developed for creating phase-space files at the exit of a linear accelerator for any arbitrary intensity and energy electron beam without the need of full Monte Carlo simulations. The model assigns each particle to one of the 3 following sources: primary, secondary collimator and electron collimator scatter. The primary component is derived by fast MC transport in air. The scatter components are derived by the use of MC pre-calculated leaf kernels. Each kernel includes the fluence distribution, energy distribution and scatter probability of generating an electron from a leaf. The original position is sampled from tunable Gaussian or uniform distributions. The direction is estimated by geometrical means. According to the projection of the direction a particle is rejected if it is expected to suffer a leaf-hit. A leaf-hit counter is used to calculate the output of scatter particles based on the pre-calculated scatter probabilities. To account for multiple coulomb scattering in air a MC-corrected version of the Fermi-Eyges scattering theory was implemented. Depth and profile dose distributions were derived for the largest and smallest square field sizes, as well as for irregular and off-axis fields. The model agreed with full MC dose distributions within 3 % in all cases. Output at the depth of maximum dose exhibited discrepancies less than 2.6 % in all cases. The model was 16-22 times faster in generating a phase-space file than a full MC simulation with the BEAMnrc code.
Collapse
Affiliation(s)
- P Papaconstadopoulos
- Medical Physics Unit, Montreal General Hospital, McGill University, Montreal, Quebec
| | - J Seuntjens
- Medical Physics Unit, Montreal General Hospital, McGill University, Montreal, Quebec
| |
Collapse
|
7
|
Abstract
PURPOSE To commission and verify an Epson scanner for film dosimetry for total skin electron beam therapy (TSEB). METHODS Use data from an IBA PPC40 parallel-plate ion chamber and Sun Nuclear QED skin diode detectors as standard; we have made comparisons to the film measurement using Kodak XV films. Hurter-Driffield (HD) curve are established for 6 MeV total skin electron beams at a source-to-surface distance (SSD) of 5 m. Also HD curves are built for 6 MeV at a 100 cm SSD. Dose profiles for a series of oblique incident large electron fields are measured using the film for approximately 80 cGy dose delivered at the peak. The film is then scanned using two scanners, an Epson expression 10000 XL and a Vidar VXR-16 Dosimetry Pro. The optimal scanning conditions (e.g., dot per pixel size, internal color correction scheme) are chosen for the Epson scanner. Matlab is then used to analyze the optical density (OD) of the scanned films. A transmission densitometer made by Tobias Associates transmission is used to analyze the films to give a classical standard. RESULTS The analysis of the Epson scanner is presented in two forms: one with and one without the HD correction from the established HD curve. The error analysis gives an uncertainty of 5% without the HD correction. An improved result of approximately 3% is found when an HD correction is applied to the analysis. CONCLUSIONS A simple Epson scanner satisfies the commissioning standards for TSEB when an HD curve correction is applied.
Collapse
Affiliation(s)
| | - K Wang
- University Pennsylvania, Philadelphia, PA
| | - S Tang
- University Pennsylvania, Philadelphia, PA
| | - T Zhu
- University Pennsylvania, Philadelphia, PA
| |
Collapse
|
8
|
Abstract
PURPOSE To verify the SBRT plans on CMS Xio treatment planning system using the Monte Carlo simulation and investigate the related issues. METHODS The SBRT plans with 6 MV were created on CMS Xio treatment planning system with superposition algorithm. The same patient's CT, beam geometry and MUs were used in the Monte Carlo simulation (MC) on MCSIM. MCSIM is an EGS4-based MC dose calculation system for photon and electron beams. The Monte Carlo plans were compared with the Xio plans to verify Xio superposition algorithm for SBRT. The electron disequilibrium was particularly investigated by comparing the DVHs for a 2-mm thick peel of the GTV. The beam energy was changed from 6 MV to 10 MV for MC to test energy effect on SBRT dosimetry. RESULTS Six SBRT lung plans created on Xio and delivered on Varian 21 EX linac were included in this study. The tumor GTV ranged from 1.4 cc to 11 cc and the dose ranged from 1950 cGy to 5400 cGy. The comparisons were made in terms of DVHs, mean doses, minimal doses, and maximal doses for GTV. The results showed all the dose values of Xio plans agreed with MC to within 2% with only two exceptions of 3% and 5%. The dose distribution in the peel of GTV followed the same pattern as the whole GTV. This indicated the Xio superposition algorithm has well accounted for electron disequilibrium. The 10-MV beams had both hot and cold spots from DVH comparison. This may be due to the large build-up region for high energy beams. CONCLUSIONS The Xio superposition algorithm has adequately accounted for electron disequilibrium and can perform accurate dose calculation for SBRT. Compared to high energy beams, 6 MV is preferable in terms of the GTV coverage and dose homogeneity.
Collapse
Affiliation(s)
- W Luo
- University of Kentucky, Lexington, KY
| | - X Xie
- University of Kentucky, Lexington, KY
| | - R McGarry
- University of Kentucky, Lexington, KY
| | - J Molloy
- University of Kentucky, Lexington, KY
| |
Collapse
|
9
|
Abstract
PURPOSE AAPM TG-142 guidelines state that beam uniformity (flatness and symmetry) should maintain a constancy of 1 % relative to baseline. The focus of this study is to determine if statistical process control (SPC) methodology using process control charts (PCC) of steering coil currents (SCC) can detect changes in beam uniformity prior to exceeding the 1% constancy criteria. METHODS SCCs for the transverse and radial planes are adjusted such that a reproducibly useful photon or electron beam is available. Transverse and radial - positioning and angle SCC are routinely documented in the Morning Check file during daily warm-up. The 6 MV beam values for our linac were analyzed using average and range (Xbar/R) PCC. Using this data as a baseline, an experiment was performed in which each SCC was changed from its mean value (steps of 0.01 or 0.02 Ampere) while holding the other SCC constant. The effect on beam uniformity was measured using a beam scanning system. These experimental SCC values were plotted in the PCC to determine if they would exceed the predetermined limits. RESULTS The change in SCC required to exceed the 1% constancy criteria was detected by the PCC for 3 out of the 4 steering coils. The reliability of the result in the one coil not detected (transverse position coil) is questionable because the SCC slowly drifted during the experiment (0.05 A) regardless of the servo control setting. CONCLUSIONS X-bar/R charts of SCC can detect exceptional variation prior to exceeding the beam uniformity criteria set forth in AAPM TG-142. The high level of PCC sensitivity to change may result in an alarm when in fact minimal change in beam uniformity has occurred. Further study is needed to determine if a combination of individual SCC alarms would reduce the false positive rate for beam uniformity intervention. This project was supoorted by a grant from Varian Medical Systems, Inc.
Collapse
Affiliation(s)
- C Able
- Wake Forest School of Medicine, Winston-Salem, NC
| | - C Hampton
- Wake Forest School of Medicine, Winston-Salem, NC
| | - A Baydush
- Wake Forest School of Medicine, Winston-Salem, NC
| |
Collapse
|
10
|
Chang Z, Wu Q, Adamson J, Ren L, Bowsher J, Yan H, Thomas A, Yin F. SU-E-T-104: Commissioning and Dosimetric Characteristics of TrueBeam System: Composite Data of Three TrueBeam Machines. Med Phys 2012; 39:3726. [PMID: 28517167 DOI: 10.1118/1.4735162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
INTRODUCTION A TrueBeam linear accelerator (TB-LINAC) is designed to deliver standard flattened and flattening-filter-free (FFF) beams. In our institute, three TB-LINAC units are installed. In this work, composite data of the three units and multi-unit comparison are presented. METHODS Each TB-LINAC can deliver photon beams from 4MV to 15MV, electron beams from 6MeV to 22MeV, and 6MV-FFF and 10MV-FFF. Dosimetric characteristics are systematically measured for commissioning including percent depth dose (PDD), beam profile, relative scatter factor, dynamic leaf shift, output factor and MLC leakage. Critic considerations of Pion of FFF photon beams and dosimetric penumbra are investigated. RESULTS All measured PDDs and profiles of photon and electron matched well across the three machines. Beam data were quantitatively compared and combined through average to yield composite beam data. The discrepancies among the machines were quantified using standard deviation (SD). For example, the mean SD of the PDDs among the three units is 0.12%, and the mean SD of the profiles is 0.40% for 10MV-FFF open fields. The variations of Pion of the chamber CC13 is 1.2±0.1% under 6MV-FFF and 2.0±0.5% from dmax to the 18cm-off-axis point at 35cm depth under 40×40cm2 . The measured relative output factors range from 0.866 to 1.141 with the mean discrepancy of 0.06±0.04% among the three units. The measured wedge factors range from 0.863 to 1.254 with the mean overall discrepancy of 0.04±0.04%. The mean MLC transmission and dynamic leaf shift were measured from 1.0% to 1.5% and from 0.77mm to 0.96 mm from 4MV to 15MV. The mean penumbra of various photon beams are measured from 5.88±0.09mm to 5.99±0.13mm from 4MV to 15MV at 10cm depth of 10×10 cm2 . CONCLUSIONS Dosimetric data demonstrated that the three units could and had been matched well. The systematically measured data might be useful for future reference.
Collapse
Affiliation(s)
- Z Chang
- Duke University Medical Center, Durham, NC
| | - Q Wu
- Duke University Medical Center, Durham, NC
| | - J Adamson
- Duke University Medical Center, Durham, NC
| | - L Ren
- Duke University Medical Center, Durham, NC
| | - J Bowsher
- Duke University Medical Center, Durham, NC
| | - H Yan
- Duke University Medical Center, Durham, NC
| | - A Thomas
- Duke University Medical Center, Durham, NC
| | - F Yin
- Duke University Medical Center, Durham, NC
| |
Collapse
|
11
|
Alezra D, Nardi E, Koren S, Bragilovski D, Orion I. SU-E-T-279: A Novel Electron-Beam Combined with Magnetic Field Application for Radiotherapy. Med Phys 2012; 39:3767-3768. [PMID: 28517301 DOI: 10.1118/1.4735347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The new beam and delivery system consists of an electron accelerator and a system of magnets (one or more). Introducing a transverse magnetic field in and near the tumor, causes the electrons to spiral in this region, thereby producing an effective peak in the depth dose distribution, within the tumor volume. Although the basic idea is not new, we suggest here for the first time, a viable as well as a workable, magnetic field configuration, which in addition to focusing the beam does not interfere with its propagation to the target. METHODS The electron accelerator: can be a linear accelerator or any other type electron accelerator, capable of producing different electron energies for different depths and dose absorption accumulation. The Field size can be as small as a pencil beam and as big as any of the other standard field sizes that are used in radiotherapy. The scatter filter can be used or removed. The dose rate accumulation can be as higher as possible.The magnets are able to produce magnetic fields. The order, direction, width, place, shape and number of the magnetic fields define the shape and the Percentage Depth Dose (PDD) curve of the electron beam. Prototypes were successfully tested by means of computer simulation, using:COMSOL-Multiphsics for magnetic fields calculations. FLUKA package, for electron beam MC simulation. RESULTS Our results suggest that by using an electron beam at different energies, combined with magnetic fields, we could modify the delivered dose. This is caused by manipulating the electron motion via the Lorentz force. The applied magnetic field, will focus the electron beam at a given depth and deposit the energy in a given volume and depth, where otherwise the electron energy will have spread deeper. The direction and magnitude of the magnetic fields will prevent the scattering of the electron beam and its absorption in remote volumes. In practice, we get a pseudo Bragg peak depth dose distribution, applying a relatively low cost system. The therapeutic efficiency induced by the system is of similar efficiency as the ion beam therapy techniques. CONCLUSIONS Our novel concept demonstrates treatment that is almost similar to proton therapy and in some parameters even better performance.Unlike the current high-energy electron therapy, our system's beam deposit almost all of its energy on its target, with a low amount of radiation deposited in tissues from the surface of the skin to the front of tumor, and almost no "exit dose" beyond the tumor. This property will enables to hit tumors with higher, potentially more effective radiation doses, while being considerably less expensive.
Collapse
Affiliation(s)
- D Alezra
- Sheba Medical Center, Tel Hashomer.,Nuclear Engineering Dept, Ben Gurion University, Beer Sheva
| | - E Nardi
- Sheba Medical Center, Tel Hashomer.,Nuclear Engineering Dept, Ben Gurion University, Beer Sheva
| | - S Koren
- Sheba Medical Center, Tel Hashomer.,Nuclear Engineering Dept, Ben Gurion University, Beer Sheva
| | - D Bragilovski
- Sheba Medical Center, Tel Hashomer.,Nuclear Engineering Dept, Ben Gurion University, Beer Sheva
| | - I Orion
- Sheba Medical Center, Tel Hashomer.,Nuclear Engineering Dept, Ben Gurion University, Beer Sheva
| |
Collapse
|
12
|
Zhang M, Qin S, Haffty B, Yue N. SU-E-T-10: Monte Carlo Study of the Dose Enhancement Factor (DEF) for Gold Nano-Particle (GNP) on the Cellular Level. Med Phys 2012; 39:3704. [PMID: 28519059 DOI: 10.1118/1.4735064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE In megavoltage external beam radiotherapy, in vivo cell experiments suggest GNP could be used as a radiosensitizer by having radiation dose enhancement factor (DEF) significantly larger than 1. However, Monte Carlo (MC) simulations published in the literature failed to give prove, in which most of them only simulated the interactions between the radiation beams and a single GNP. In this study, we built a multi-GNPs model considering possible spatial arrangements of GNPs relative to a cell to calculate the DEFs of GNPs. METHODS Geant4 MC code with G4DNA physics model which can trace electrons down to eV level was used. Two types of geometry models representing different GNP-cell binding were created with each GNP modeled individually: (1) shell model with GNPs randomly and sparsely distributed in a shell in water mimicking when the GNPs were binding to the cell membrane, and (2) sphere model with GNPs randomly and sparsely distributed in a sphere in water mimicking when GNPs were floating inside the cytoplasm. Photon and electron spectrum at 5 cm in depth in water from a Varian 6MV beam was used as the radiation source. Dose to water inside the shell or the sphere representing cytoplasm were scored and compared to situations without GNPs to calculate the DEF. We also looked into the variation of DEFs due to different GNP sizes and concentrations. RESULTS A 35 um water cubic were successfully built in Geant4 with spatial resolution of 100 nm. Preliminary results shown under 200 keV electron irradiation, 100 nm GNPs in the shell model shown increased dose to cell at the beam entrance (DEF = 1.08). CONCLUSIONS The computation is undergoing for different GNP sizes and concentrations. Meaningful results are expected on the completion of this study.
Collapse
Affiliation(s)
- M Zhang
- The Cancer Institute of New Jersey, New Brunswick, NJ.,The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - S Qin
- The Cancer Institute of New Jersey, New Brunswick, NJ.,The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - B Haffty
- The Cancer Institute of New Jersey, New Brunswick, NJ.,The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - N Yue
- The Cancer Institute of New Jersey, New Brunswick, NJ.,The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| |
Collapse
|
13
|
Gebreamlak W, Tedeschi D, Alkhatib H. SU-F-BRCD-03: Dose Calculation of Electron Therapy Using Improved Lateral Buildup Ratio Method. Med Phys 2012; 39:3856. [PMID: 28517539 DOI: 10.1118/1.4735741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To calculate the percentage depth dose of any irregular shape electron beam using modified lateral build-up-ratio method. METHOD AND MATERIALS Percentage depth dose (PDD) curves were measured using 6, 9, 12, and 15MeV electron beam energies for applicator cone sizes of 6×6, 10×10, 14×14, and 14×14cm2 . Circular cutouts for each cone were prepared from 2.0cm diameter to the maximum possible size for each cone. In addition, three irregular cutouts were prepared. The scanning was done using a water tank and two diodes - one for the signal and the other a stationary reference outside the tank. The water surface was determined by scanning the signal diode slowly from water to air and by noting the sharp change of the percentage depth dose curve at the water/air interface. RESULTS The lateral build-up-ratio (LBR) for each circular cutout was calculated from the measured PDD curve using the open field of the 14×14 cm2 cone as the reference field. Using the LBR values and the radius of the circular cutouts, the corresponding lateral spread parameter (sigma) of the electron shower was calculated. Unlike the commonly accepted assumption that sigma is independent of cutout size, it is shown that the sigma value increases linearly with circular cutout size. Using this characteristic of sigma, the PDD curves of irregularly shaped cutouts were calculated. Finally, the calculated PDD curves were compared with measured PDD curves. CONCLUSIONS In this research, it is shown that sigma increases with cutout size. For radius of circular cutout sizes up to the equilibrium range of the electron beam, the increase of sigma with the cutout size is linear. The percentage difference of the calculated PDD from the measured PDD for irregularly shaped cutouts was under 1.0%. Similar Result was obtained for four electron beam energies (6, 9, 12, and 15MeV).
Collapse
Affiliation(s)
- W Gebreamlak
- University of South Carolina, Columbia, SC.,Richland Memorial Hospital, Columbia, SC
| | - D Tedeschi
- University of South Carolina, Columbia, SC.,Richland Memorial Hospital, Columbia, SC
| | - H Alkhatib
- University of South Carolina, Columbia, SC.,Richland Memorial Hospital, Columbia, SC
| |
Collapse
|
14
|
Carver R, Hogstrom K, Price M, Leblanc J, Harris G. SU-E-T-25: Real Time Simulator for Designing Electron Dual Scattering Foil Systems. Med Phys 2012; 39:3708. [PMID: 28519026 DOI: 10.1118/1.4735080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To create a user friendly, accurate, real time computer simulator to facilitate the design of dual foil scattering systems for electron beams on radiotherapy accelerators. The simulator should allow for a relatively quick, initial design that can be refined and verified with subsequent Monte Carlo (MC) calculations and measurements. METHODS The simulator consists of an analytical algorithm for calculating electron fluence and a graphical user interface (GUI) C++ program. The algorithm predicts electron fluence using Fermi-Eyges multiple Coulomb scattering theory with a refined Moliere formalism for scattering powers. The simulator also estimates central-axis x-ray dose contamination from the dual foil system. Once the geometry of the beamline is specified, the simulator allows the user to continuously vary primary scattering foil material and thickness, secondary scattering foil material and Gaussian shape (thickness and sigma), and beam energy. The beam profile and x-ray contamination are displayed in real time. RESULTS The simulator was tuned by comparison of off-axis electron fluence profiles with those calculated using EGSnrc MC. Over the energy range 7-20 MeV and using present foils on the Elekta radiotherapy accelerator, the simulator profiles agreed to within 2% of MC profiles from within 20 cm of the central axis. The x-ray contamination predictions matched measured data to within 0.6%. The calculation time was approximately 100 ms using a single processor, which allows for real-time variation of foil parameters using sliding bars. CONCLUSIONS A real time dual scattering foil system simulator has been developed. The tool has been useful in a project to redesign an electron dual scattering foil system for one of our radiotherapy accelerators. The simulator has also been useful as an instructional tool for our medical physics graduate students.
Collapse
Affiliation(s)
- R Carver
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A&M College, Baton Rouge, LA
| | - K Hogstrom
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A&M College, Baton Rouge, LA
| | - M Price
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A&M College, Baton Rouge, LA
| | - J Leblanc
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A&M College, Baton Rouge, LA
| | - G Harris
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A&M College, Baton Rouge, LA
| |
Collapse
|
15
|
Alvarez P, Aguirre J, Smith S, Followill D. SU-E-T-102: Evaluation of the Characteristics of TLD LiF:Mg.Ti-100 Powder: A Measure of Consistency between Multiple Batches of Powder. Med Phys 2012; 39:3726. [PMID: 28517137 DOI: 10.1118/1.4735160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Analyze the characteristics of TLD LiF-100 powder between multiple LiF crystal batches. METHODS The RPC used TLD LiF-100 encapsulated powder to verify the output for photon and electron beams for 4 to 23 MV X-ray beams and 6 to 23 MeV electron beams, respectively, from the past 15 years. During that time period, the RPC commissioned more than 15 batches of TLD powder. Commissioning of each batch of powder encompassed determining the system sensitivity (dose response), linearity, energy and fading characteristics of each batch of powder to determine the correction factors for the calculation of dose. The system sensitivity is the signal/mg per unit known dose of 60Co for each reading session. Other correction factors account for the loss of signal (fading) between the irradiation and read dates, supralinearity of the dose response and energy differences as compared to the 60Co irradiated standards. RESULTS More than 15 batches of TLD were commissioned to determine correction factors for the calculation of dose. The correction for fading, a characteristic of the LiF crystal, varied by ±1% between the multiple batches. The linearity correction, between 25 and 600cGy, normalized to 300cGy, showed a maximum variation of ±3% between batches. The energy correction factors, as defined for the RPC beam output audit system varied within ±1.7% (one std dev.) for the 15 batches. The system sensitivity is highly dependent on the LiF crystal grown for each batch, specific TLD reader and reading session conditions. The system sensitivity, while keeping the readers and reading sessions constant, varied by as much as 20% between batches. CONCLUSIONS Each batch of LiF-100 TLD powder showed variability in their powder characteristics such that calculation of dose accurately, with minimal uncertainty, requires a new commissioning. Work supported by PHS CA010953 awarded by NCI, DHHS.
Collapse
Affiliation(s)
- P Alvarez
- UT MD Anderson Cancer Center, Houston, TX
| | - J Aguirre
- UT MD Anderson Cancer Center, Houston, TX
| | - S Smith
- UT MD Anderson Cancer Center, Houston, TX
| | | |
Collapse
|
16
|
Eldib A, Li J, Jin L, Ma C. SU-E-T-441: A Feasibility Study to Replace Electron Cutouts with a Motorized Electron Multileaf Collimator. Med Phys 2012; 39:3806. [PMID: 28517433 DOI: 10.1118/1.4735530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Fabrication of electron beam cutouts not only is a time consuming process but also involves the handling of cerrobend which is a toxic material. Hospital workers involved in cutout construction can actually be exposed to toxic fumes that are usually generated during the process. The aim of this work is to study the feasibility of replacing electron cutouts with our prototype motorized electron multileaf collimator (eMLC). METHODS Electron beams collimated by an eMLC have very similar penumbra to those collimated by applicators and cutouts as we already demonstrated in a previous study. However undulation of the isodose curves is expected due to the finite size of the eMLC. This may be a problem when the field edge is close to critical structure. Thus ten different breast cases that were previously treated with an electron boost were selected from our database. An inhouse Monte Carlo based treatment planning system were used for dose calculation using the patients CTs. For each patient two plans were generated one with electron beams collimated using the applicator/cutout combination and the other plan with beams collimated only by the eMLC. Treatment plan quality was compared for each patient based on dose distribution and dose volume histogram. In order to determine the optimal position of the leaves, the impact of the different leaf positioning strategies were investigated. RESULTS Results have shown that target coverage and critical structure sparing can be effectively achieved by electron beams collimated by eMLC. Preliminary results have shown that the out-of-field strategy is most conservative and would be the recommended method to define the actual leaf position for the eMLC defined field. CONCLUSION The eMLC represents an effective time saving and pollution free device that can completely eliminate the need for patient specific cutouts. This work has been supported by a UICC American Cancer Society Beginning Investigators Fellowship funded by the American Cancer Society.
Collapse
Affiliation(s)
- A Eldib
- Fox Chase Cancer Center, Philadelphia, PA.,AlAZhar University, Department of physics, Cairo, Egypt
| | - J Li
- Fox Chase Cancer Center, Philadelphia, PA.,AlAZhar University, Department of physics, Cairo, Egypt
| | - L Jin
- Fox Chase Cancer Center, Philadelphia, PA.,AlAZhar University, Department of physics, Cairo, Egypt
| | - C Ma
- Fox Chase Cancer Center, Philadelphia, PA.,AlAZhar University, Department of physics, Cairo, Egypt
| |
Collapse
|
17
|
Das I, Chu C, Conlon J, Neck D, Gibbons J. SU-E-T-97: Intra and Inter Variability in Beam Data Commissioning among Water Phantom Scanning Systems. Med Phys 2012; 39:3725. [PMID: 28517127 DOI: 10.1118/1.4735154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE There are many water-phantom scanning systems with advanced features to collect accurate commissioning data. However the intra- and inter-variability of commissioning data has not been reported which is attempted in this study. METHODS Four vendors with modern water-phantom scanning systems; PTW, Sun Nuclear (SN), Standard Imaging (SI) and IBA were invited to an institution to demonstrate beam data collection. Each system was used to collect percent depth dose (PDD) and profiles several times in a day with their choice of detector for four different machines for photon and electron beam commissioning. This provided information on intra-variability. At the end, each vendor was allowed to setup and collect data on a single unit for inter-variability. All data were sent to a central location for analysis and evaluation. RESULTS The depth dose and profiles for 2×2cm2 and 10×10cm2 fields were analyzed for intra- and inter-variability. With repeated measurements, the intra-variability provided a detailed degree of fidelity of data collection. This was shown to be with (± 0.1%) among all vendors. Ignoring data in buildup region and comparing with one system (PTW), the PDDs variability were slightly larger 0.02±0.17%, 0.14±0.21%, 0.17±0.2%, for SI, SN and IBA, respectively. The profiles inter-variability in central region were <0.1 %, however in penumbra up to ± 4.8%were observed. The polarity effect was also noted up to 3% which was depth and detector dependent. CONCLUSIONS Intra- and inter-variability among various scanning system are very small indicting that all modern systems if used properly could collect data within±0.2% accuracy. The selection of device should be based on institutional comfort and personal preference of software and hardware. This study provides unique opportunity to compare data among systems which is otherwise not possible.
Collapse
Affiliation(s)
- I Das
- Indiana University-School of Medicine, Indianapolis, IN.,Mary Bird Perkins Cancer Center, Baton Rouge, LA.,West Des Moines, IA
| | - C Chu
- Indiana University-School of Medicine, Indianapolis, IN.,Mary Bird Perkins Cancer Center, Baton Rouge, LA.,West Des Moines, IA
| | - J Conlon
- Indiana University-School of Medicine, Indianapolis, IN.,Mary Bird Perkins Cancer Center, Baton Rouge, LA.,West Des Moines, IA
| | - D Neck
- Indiana University-School of Medicine, Indianapolis, IN.,Mary Bird Perkins Cancer Center, Baton Rouge, LA.,West Des Moines, IA
| | - J Gibbons
- Indiana University-School of Medicine, Indianapolis, IN.,Mary Bird Perkins Cancer Center, Baton Rouge, LA.,West Des Moines, IA
| |
Collapse
|
18
|
Zhang G, Javedan K, Moros E, Latifi K, Feygelman V, Moffitt HL. SU-E-T-479: Skin Dose from Flattening Filter Free Beams: A Monte Carlo Investigation. Med Phys 2012; 39:3815. [PMID: 28517489 DOI: 10.1118/1.4735568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Flattening filter free (FFF) beams in radiotherapy have advantages such as shorter treatment delivery time and lower out-of-field dose compared with conventional flattened beams. This study investigates in detail the skin dose induced by FFF beams from a TrueBeam accelerator (Varian Medical Systems, Palo Alto, CA) using Monte Carlo method. METHODS Phase space files generated using real geometry of a TrueBeam accelerator above the jaws, were used as the input radiation source files in beam simulation for various field sizes using BEAMnrc. Phase space files for various field sizes were generated at the phantom surface. DOSXYZnrc was used for dose calculations in phantom and in patient using the generated phase space files as source input files. RESULTS The calculated percentage depth dose curves and profiles in water agreed with measurements within ± 2% for the high dose region and ±2 mm in the penumbra. The peak fluence of a 6 MV FFF beam with the same electron beam incident on the target is about 3 times that of a flattened beam . The mean energy of a 6 MV FFF beam is 0.92-0.95 MeV while it is 1.18-1.30 MeV for the flattened beam. Due to the mean energy difference, the dose in a 6 MV FFF beam is about 6% (of the maximum dose, or 12% of local dose) higher at depth of 1 mm compared with a flattened beam. CONCLUSIONS Due to the lower mean photon energy, in an FFF beam the surface (skin) dose is slightly higher compared to the conventional flattened beam of the same field size.
Collapse
|
19
|
Pianoschi T, Alva-Sánchez M, Santanna M, César D, Nicolucci P. SU-E-T-278: Study of MAGIC-F Gel and PENELOPE Code Simulation Response for Clinical Electron Beams. Med Phys 2012; 39:3767. [PMID: 28517259 DOI: 10.1118/1.4735346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To evaluate the response of MAGIC-f gel through dose response curves, percentage depth dose (PDD) and beam profile for clinical electron beams. METHODS Glass tubes (Vacutainer ®), with 6 cm length and 0.5 cm radius, with MAGIC-f were positioned inside a water phantom to study the gel response with doses from 0.5 Gy to 20 Gy in electron beams of 6, 9 e 12 MeV. Glass tubes of 20 cm length and 1 cm radius and PMMA phantoms of 10 × 5 × 5 cm3 were used to PDD and beam profiles determinations, respectively, with a maximum dose of 2 Gy to the gel. The samples were analyzed through magnetic resonance imaging (MRI) with a 3 T tomography using a head coil, multiple spin echo sequence with 16 echos, TE 15ms and TR 4000ms. The MAGIC-f response was simulated with PENELOPE Monte Carlo code in the same geometry used in the irradiations. The results obtained with MAGIC-f and PENELOPE were compared with clinical data. RESULTS Calibration curves for MAGIC-f showed a linear behavior, with correlation coefficient of 0.99, for all energies. The PDD and beam profile curves obtained with MAGIC-f presented differences lower than 1.5% and 3.0%, respectively, when compared to clinical data. Results obtained by PENELOPE and clinical data showed differences up to 1.0% and 1.5%, respectively, for PDD and profile curves. CONCLUSIONS The dosimetric parameters for electron beams obtained experimentally with MAGIC-f and with PENELOPE code showed similar results to the clinical data. From the results it can be inferred that MAGIC-f can be used as a complementary dosimetric tool for electron beams due to its characteristics of high spatial resolution and the ability to construct tridimensional dose distributions. Also PENELOPE can be used to study MAGIC-f gel response in electron beams.
Collapse
Affiliation(s)
- T Pianoschi
- University of São Paulo, Ribeirão Preto, São Paulo.,Hospital do Câncer de Barretos, Barretos, São Paulo
| | - M Alva-Sánchez
- University of São Paulo, Ribeirão Preto, São Paulo.,Hospital do Câncer de Barretos, Barretos, São Paulo
| | - M Santanna
- University of São Paulo, Ribeirão Preto, São Paulo.,Hospital do Câncer de Barretos, Barretos, São Paulo
| | - D César
- University of São Paulo, Ribeirão Preto, São Paulo.,Hospital do Câncer de Barretos, Barretos, São Paulo
| | - P Nicolucci
- University of São Paulo, Ribeirão Preto, São Paulo.,Hospital do Câncer de Barretos, Barretos, São Paulo
| |
Collapse
|
20
|
Hogstrom K, McLaughlin D, Gibbons J, Shikhaliev P, Clarke T, Henderson A, Taylor D, Shagin P, Liang E. SU-D-BRCD-06: Measurement of Elekta Electron Energy Spectra Using a Small Magnetic Spectrometer. Med Phys 2012; 39:3614. [PMID: 28517408 DOI: 10.1118/1.4734672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To demonstrate how a small magnetic spectrometer can measure the energy spectra of seven electron beams on an Elekta Infinity tuned to match beams on a previously commissioned machine. METHODS Energyspectra were determined from measurements of intensity profiles on 6″-long computed radiographic (CR) strips after deflecting a narrow incident beam using a small (28 lbs.), permanent magnetic spectrometer. CR plateexposures (<1cGy) required special beam reduction techniques and bremsstrahlung shielding. Curves of CR intensity (corrected for non- linearity and background) versus position were transformed into energy spectra using the transformation from position (x) on the CR plate to energy (E) based on the Lorentz force law. The effective magnetic field and its effective edge, parameters in the transformation, were obtained by fitting a plot of most probable incident energy (determined from practical range) to the peak position. RESULTS The calibration curve (E vs. x) fit gave 0.423 Tesla for the effective magnetic field. Most resulting energy spectra were characterized by a single, asymmetric peak with peak position and FWHM increasing monotonically with beam energy. Only the 9-MeV spectrum was atypical, possibly indicating suboptimal beam tuning. These results compared well with energy spectra independently determined by adjusting each spectrum until the EGSnrc Monte Carlo calculated percent depth-dose curve agreed well with the corresponding measured curve. CONCLUSIONS Results indicate that this spectrometer and methodology could be useful for measuring energy spectra of clinical electron beams at isocenter. Future work will (1) remove the small effect of the detector response function (due to pinhole size and incident angular spread) from the energy spectra, (2) extract the energy spectra exiting the accelerator from current results, (3) use the spectrometer to compare energy spectra of matched beams among our clinical sites, and (4) modify the spectrometer to utilize radiochromic film.
Collapse
Affiliation(s)
- K Hogstrom
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - D McLaughlin
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - J Gibbons
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - P Shikhaliev
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - T Clarke
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - A Henderson
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - D Taylor
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - P Shagin
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| | - E Liang
- Mary Bird Perkins Cancer Center, Baton Rouge, LA.,Louisiana State University and A & M College, Baton Rouge, LA.,Rice University, Houston, TX
| |
Collapse
|
21
|
Chu A, Feng W, Ahmad M, Chen Z, Nath R. SU-E-T-269: The Evaluation of Copper as an Alternative for Cerrobend Electron Shielding. Med Phys 2012; 39:3765. [PMID: 28517300 DOI: 10.1118/1.4735336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To evaluate the replacement of Cerrobend by copper for electron beam cutouts. METHODS The dosimetric comparisons for circular copper-and Cerrobend-cutouts with diameters (1.0, 2.0, 3.0, 5.0, 7.5, 10.0, and 12.5 cm) were made using electron beams with energies (6, 9, 12, 16, and 20 MeV) from 3 Varian accelerators. A PTW Farmer chamber (0.125cc-volume) was used for larger cutouts (diameters > 2cm), and an electron-diode for the 2 smallest cutouts. Also a Markus parallel plate chamber was used. RESULTS (1) The tests showed little difference for the electron dosimetric characteristics, Eo, Eop, R50, Rp, and dmax. For larger cutout, the parameters were virtually the same for copper and Cerrobend. for smaller cutout (diameter = 3cm), small discrepancies were observed i.e. differences < 1mm for R50, Rp and dmax, =0.1MeV for Eop, and =0.3MeV for Eo. (2) The larger-cutout outputs at dmax were also virtually the same (difference = 0.6%). For smaller cutouts (diameters = 3cm), the copper outputs were 2.0%∼5.0% higher than Cerrobend. (3) For lower energy electrons (<12MeV), more larger-angle scattered electrons from higher-Z Cerrobend raise the Cerrobend percentage-depth-dose (PDD) curve at shallow-depths, and more forward scatter dose after dmax from lower-Z copper shifts the copper PDD slightly away from the one of Cerrobend. for higher energy electrons (= 12MeV), the shallow-dose difference becomes smaller for both cutouts, but even more forward-scattered dose from copper shifts copper's PDD further away from Cerrobend's. (4) The higher X-ray transmission through copper is also observable; i.e. 12%, 10%, and 7% for 20MeV, 16MeV, and 12MeV, respectively, but such small transmitted amount is clinically insignificant. CONCLUSIONS Except for a higher x-ray transmission, other dosimetric differences brought in by the replacement of Cerrobend by copper cutout are negligible.
Collapse
Affiliation(s)
- A Chu
- Yale New Haven Hospital, New Haven, CT.,New York Presbyterian Hospital, TENAFLY, NJ.,Yale New Haven Hospital, New Haven, CT.,Yale New Haven Hospital, New Haven, CT.,Yale University School of Medicine, New Haven, CT
| | - W Feng
- Yale New Haven Hospital, New Haven, CT.,New York Presbyterian Hospital, TENAFLY, NJ.,Yale New Haven Hospital, New Haven, CT.,Yale New Haven Hospital, New Haven, CT.,Yale University School of Medicine, New Haven, CT
| | - M Ahmad
- Yale New Haven Hospital, New Haven, CT.,New York Presbyterian Hospital, TENAFLY, NJ.,Yale New Haven Hospital, New Haven, CT.,Yale New Haven Hospital, New Haven, CT.,Yale University School of Medicine, New Haven, CT
| | - Z Chen
- Yale New Haven Hospital, New Haven, CT.,New York Presbyterian Hospital, TENAFLY, NJ.,Yale New Haven Hospital, New Haven, CT.,Yale New Haven Hospital, New Haven, CT.,Yale University School of Medicine, New Haven, CT
| | - R Nath
- Yale New Haven Hospital, New Haven, CT.,New York Presbyterian Hospital, TENAFLY, NJ.,Yale New Haven Hospital, New Haven, CT.,Yale New Haven Hospital, New Haven, CT.,Yale University School of Medicine, New Haven, CT
| |
Collapse
|
22
|
González LN, Arruda-Neto JDT, Cotta MA, Carrer H, Garcia F, Silva RAS, Moreau ALD, Righi H, Genofre GC. DNA fragmentation by gamma radiation and electron beams using atomic force microscopy. J Biol Phys 2012; 38:531-42. [PMID: 23729912 DOI: 10.1007/s10867-012-9270-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 04/24/2012] [Indexed: 10/28/2022] Open
Abstract
Double-stranded pBS plasmid DNA was irradiated with gamma rays at doses ranging from 1 to 12 kGy and electron beams from 1 to 10 kGy. Fragment-size distributions were determined by direct visualization, using atomic force microscopy with nanometer-resolution operating in non-tapping mode, combined with an improved methodology. The fragment distributions from irradiation with gamma rays revealed discrete-like patterns at all doses, suggesting that these patterns are modulated by the base pair composition of the plasmid. Irradiation with electron beams, at very high dose rates, generated continuous distributions of highly shattered DNA fragments, similar to results at much lower dose rates found in the literature. Altogether, these results indicate that AFM could supplement traditional methods for high-resolution measurements of radiation damage to DNA, while providing new and relevant information.
Collapse
Affiliation(s)
- Luis Nieto González
- Departamento de Ciência e Tecnologia, Universidade Estadual de Santa Cruz, Ilhéus, BA Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|