TY - JOUR
T1 - Dosimetric characteristics of an electron multileaf collimator for modulated electron radiation therapy
AU - Eldib, Ahmed A.
AU - ElGohary, Mohamed I.
AU - Fan, Jiajin
AU - Jin, Lihui
AU - Li, Jinsheng
AU - Ma, C. M.Charlie
AU - Elsherbini, Nader A.
PY - 2010
Y1 - 2010
N2 - Modulated electron radiation therapy (MERT) has been proven as an effective way to deliver conformal dose distributions to shallow tumors while sparing distal critical structures and surrounding normal tissues. It had been shown that a dedicated electron multileaf collimator (eMLC) is necessary to reach the full potential of MERT. In this study, a manually-driven eMLC for MERT was investigated. Percentage depth dose (PDD) curves and profiles at different depths in a water tank were measured using ionization chamber and were also simulated using the Monte Carlo method. Comparisons have been performed between PDD curves and profiles collimated using the eMLC and conventional electron applicators with similar size of opening. Monte Carlo simulations were performed for all electron energies available (6, 9, 12, 15, 18 and 20 MeV) on a Varian 21EX accelerator. Monte Carlo simulation results were compared with measurements which showed good agreement (< 2%/1mm). The simulated dose distributions resulting from multiple static electron fields collimated by the eMLC agreed well with measurements. Further studies were carried out to investigate the properties of abutting electron beams using the eMLC, as it is an essential issue that needs to be addressed for optimizing the MERT outcome. A series of empirical formulas for abutting beams of different energies have been developed for obtaining the optimum gap sizes, which can highly improve the target dose uniformity.
AB - Modulated electron radiation therapy (MERT) has been proven as an effective way to deliver conformal dose distributions to shallow tumors while sparing distal critical structures and surrounding normal tissues. It had been shown that a dedicated electron multileaf collimator (eMLC) is necessary to reach the full potential of MERT. In this study, a manually-driven eMLC for MERT was investigated. Percentage depth dose (PDD) curves and profiles at different depths in a water tank were measured using ionization chamber and were also simulated using the Monte Carlo method. Comparisons have been performed between PDD curves and profiles collimated using the eMLC and conventional electron applicators with similar size of opening. Monte Carlo simulations were performed for all electron energies available (6, 9, 12, 15, 18 and 20 MeV) on a Varian 21EX accelerator. Monte Carlo simulation results were compared with measurements which showed good agreement (< 2%/1mm). The simulated dose distributions resulting from multiple static electron fields collimated by the eMLC agreed well with measurements. Further studies were carried out to investigate the properties of abutting electron beams using the eMLC, as it is an essential issue that needs to be addressed for optimizing the MERT outcome. A series of empirical formulas for abutting beams of different energies have been developed for obtaining the optimum gap sizes, which can highly improve the target dose uniformity.
KW - Computer Simulation
KW - Electrons
KW - Humans
KW - Monte Carlo Method
KW - Neoplasms/radiotherapy
KW - Radiometry/methods
KW - Radiotherapy Dosage
KW - Radiotherapy Planning, Computer-Assisted/methods
KW - Radiotherapy, High-Energy/instrumentation
KW - Radiotherapy, Intensity-Modulated
UR - http://www.scopus.com/inward/record.url?scp=77954366666&partnerID=8YFLogxK
U2 - 10.1120/jacmp.v11i2.2913
DO - 10.1120/jacmp.v11i2.2913
M3 - Article
C2 - 20592689
AN - SCOPUS:77954366666
SN - 1526-9914
VL - 11
SP - 5
EP - 22
JO - Journal of Applied Clinical Medical Physics
JF - Journal of Applied Clinical Medical Physics
IS - 2
ER -