Van Eeden, Déte, Sachse, Karl N., Du Plessis, Freek C.P.. (1400). Practical Dosimetry Considerations for Small MLC-Shaped Electron Fields at 60 cm SSD. سامانه مدیریت نشریات علمی, 12(1), 101-108. doi: 10.31661/jbpe.v0i0.2004-1097
Déte Van Eeden; Karl N. Sachse; Freek C.P. Du Plessis. "Practical Dosimetry Considerations for Small MLC-Shaped Electron Fields at 60 cm SSD". سامانه مدیریت نشریات علمی, 12, 1, 1400, 101-108. doi: 10.31661/jbpe.v0i0.2004-1097
Van Eeden, Déte, Sachse, Karl N., Du Plessis, Freek C.P.. (1400). 'Practical Dosimetry Considerations for Small MLC-Shaped Electron Fields at 60 cm SSD', سامانه مدیریت نشریات علمی, 12(1), pp. 101-108. doi: 10.31661/jbpe.v0i0.2004-1097
Van Eeden, Déte, Sachse, Karl N., Du Plessis, Freek C.P.. Practical Dosimetry Considerations for Small MLC-Shaped Electron Fields at 60 cm SSD. سامانه مدیریت نشریات علمی, 1400; 12(1): 101-108. doi: 10.31661/jbpe.v0i0.2004-1097
Practical Dosimetry Considerations for Small MLC-Shaped Electron Fields at 60 cm SSD
1PhD, Medical Physics Department, Faculty of Health Sciences, University of the Free State, P.O. Box 339, Bloemfontein, 9300 South Africa
2MSc, Department of Medical Physics, Faculty of Health Sciences, University of the Free State, Bloemfontein, South Africa
3PhD, Department of Medical Physics, Faculty of Health Sciences, University of the Free State, Bloemfontein, South Africa
چکیده
Superficial tumours can be treated with megavoltage electron beams. The underlying tissue can be spared through the steep dose fall-off gradients over a range of a few centimetres. An accurate Monte Carlo model for an Elekta Precise was determined and dose distribution was simulated. Dosimetric parameters were calculated to set guidelines for tumour irradiation. Elekta Precise multi-leaf collimators (MLC), which shaped electron fields were investigated using a benchmarked Monte Carlo model. BEAMnrc modelled the Elekta Precise and results were benchmarked against measurements. Percentage depth dose and beam profile data were simulated within 2% / 2 mm accuracy of the measured data. The DOSXYZnrc code simulated the 3-D dose data in water between 4 and 15 MeV. The relative (p 80-20) penumbra, percentage depth dose (PDD), range to 90% of dose maximum (R90), dose fall-off range R80-20 (DFR), and the percentage bremsstrahlung dose (BSD), were extracted from the simulated data. The relative penumbra ranged from 90% to 10% at 6 MeV and 15 MeV, respectively. R90 values ranged between 0.8 cm at 4 MeV and 4.5 cm at 15 MeV. The DFR ranged between 0.8 cm at 4 MeV and 3.5 cm at 15 MeV. The BSD was the highest for low beam energies and small fields. Developed guidelines indicated that intermediate-sized MLC fields are most suited for therapy since they have lower BSD, longer R90, shorter DFR but larger P80-20. The DFR increases and R90 decreases for small fields at higher beam energies and more distal tissue will receive doses > 20%.
Hogstrom KR, Boyd RA, Antolak JA, Svatos MM, Faddegon BA, Rosenman JG. Dosimetry of a prototype retractable eMLC for fixed-beam electron therapy. Med Phys. 2004;31(3):443-62. doi: 10.1118/1.1644516. PubMed PMID: 15070241.
Moran JM, Martel MK, Bruinvis IA, Fraass BA. Characteristics of scattered electron beams shaped with a multileaf collimator. Med Phys. 1997;24(9):1491-8. doi: 10.1118/1.598046. PubMed PMID: 9304578.
Xiong W, Li J, Chen L, Price RA, Freedman G, Ding M, Qin L, Yang J, Ma CM. Optimization of combined electron and photon beams for breast cancer. Phys Med Biol. 2004;49(10):1973-89. doi: 10.1088/0031-9155/49/10/010. PubMed PMID: 15214536.
Hyödynmaa S, Gustafsson A, Brahme A. Optimization of conformal electron beam therapy using energy- and fluence-modulated beams. Med Phys. 1996;23(5):659-66. doi: 10.1118/1.597710. PubMed PMID: 8724738.
International Commission on Radiation Units and Measurements. Radiation Dosimetry: Electron beams with energies between 1 and 50 MeV ICRU. Report ICRU 35; USA: ICRU Publ; 1984.
Olofsson L, Mu X, Nill S, Oelfke U, Zackrisson B, Karlsson M. Intensity modulated radiation therapy with electrons using algorithm based energy/range selection methods. Radiother Oncol. 2004;73(2):223-31. doi: 10.1016/j.radonc.2004.08.020. PubMed PMID: 15542170.
Mihaljevic J, Soukup M, Dohm O, Alber M. Monte Carlo simulation of small electron fields collimated by the integrated photon MLC. Phys Med Biol. 2011;56(3):829-43. doi: 10.1088/0031-9155/56/3/018. PubMed PMID: 21242628.
Henzen D, Manser P, Frei D, Volken W, Neuenschwander H, Born EJ, Vetterli D, Chatelain C, Stampanoni MF, Fix MK. Monte Carlo based beam model using a photon MLC for modulated electron radiotherapy. Med Phys. 2014;41(2):021714. doi: 10.1118/1.4861711. PubMed PMID: 24506605.
Salguero FJ, Arráns R, Palma BA, Leal A. Intensity- and energy-modulated electron radiotherapy by means of an xMLC for head and neck shallow tumors. Phys Med Biol. 2010;55(5):1413-27. doi: 10.1088/0031-9155/55/5/010. PubMed PMID: 20150682.
Hogstrom KR, Almond PR. Review of electron beam therapy physics. Phys Med Biol. 2006;51(13):R455-89. doi: 10.1088/0031-9155/51/13/R25. PubMed PMID: 16790918.
Du Plessis FC, Leal A, Stathakis S, Xiong W, Ma CM. Characterization of megavoltage electron beams delivered through a photon multi-leaf collimator (pMLC). Phys Med Biol. 2006;51(8):2113-29. doi: 10.1088/0031-9155/51/8/011. PubMed PMID: 16585849.
Kawrakow I. Accurate condensed history Monte Carlo simulation of electron transport. I. EGSnrc, the new EGS4 version. Med Phys. 2000;27(3):485-98. doi: 10.1118/1.598917. PubMed PMID: 10757601.
Rogers DW, Faddegon BA, Ding GX, Ma CM, We J, Mackie TR. BEAM: a Monte Carlo code to simulate radiotherapy treatment units. Med Phys. 1995;22(5):503-24. doi: 10.1118/1.597552. PubMed PMID: 7643786.
O’Reilly D, Smit CJ, Du Plessis FC. Extraction of electron beam dose parameters from EBT2 film data scored in a mini phantom. Australas Phys Eng Sci Med. 2013;36(3):339-46. doi: 10.1007/s13246-013-0205-1. PubMed PMID: 23794059.
