Ant colony algorithm implementation in electron and photon Monte Carlo transport: Application to the commissioning of radiosurgery photon beams

García-Pareja, S.; Galán, P.; Manzano, Fernando Ariel; Brualla, L.; Lallena, A. M.

doi:10.1118/1.3456108

Cited by 6 publications

(5 citation statements)

References 25 publications

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“…To reduce the central processing unit (CPU) time needed for the simulations, an ant colony algorithm was used to drive variance reduction techniques. 16 In each simulation, 10 8 histories were run. The tally of dose distribution was kept in bins of 1 mm, achieving a standard deviation in the dose deposited in each bin smaller than 0.7%.…”

Section: Iia Dosimetric Evaluation Of Each Jaw Misalignmentmentioning

confidence: 99%

A jaw calibration method to provide a homogeneous dose distribution in the matching region when using a monoisocentric beam split technique

Cenizo¹,

García-Pareja²,

Galán³

et al. 2011

Med. Phys.

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Section: Iia Dosimetric Evaluation Of Each Jaw Misalignmentmentioning

confidence: 99%

A jaw calibration method to provide a homogeneous dose distribution in the matching region when using a monoisocentric beam split technique

Cenizo¹,

García-Pareja²,

Galán³

et al. 2011

Med. Phys.

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“…The ant colony method has been proven to be effective in simulations of clinical linear electron accelerators [22,23], in a study of the response of MOSFET dosimeters [24], in dosimetry calculations of radiosurgery treatments [25], in the optimization of certain radiotherapy procedures [26], and in calculations of specific absorption fractions in Nuclear Medicine [20].…”

Section: Ant Colony Methodsmentioning

confidence: 99%

“…Similarly, the number of x rays released in the relaxation of ionized atoms may be increased by splitting them and assigning to the split x rays independent random directions. These VRTs are frequently referred to as directional bremsstrahlung or x-ray splitting; they have been employed, e.g., in simulations of microanalysis measurements [32] and clinical linear accelerators [36], and in dosimetry calculations of radiosurgery [25], usually accompanied with Russian roulette to reduce the number of photons not moving towards the RoI [37]. It is also worth noticing that directional splitting can be applied in combination with interaction forcing.…”

Section: Other Methodsmentioning

confidence: 99%

Variance-Reduction Methods for Monte Carlo Simulation of Radiation Transport

2021

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After a brief description of the essentials of Monte Carlo simulation methods and the definition of simulation efficiency, the rationale for variance-reduction techniques is presented. Popular variance-reduction techniques applicable to Monte Carlo simulations of radiation transport are described and motivated. The focus is on those techniques that can be used with any transport code, irrespective of the strategies used to track charged particles; they operate by manipulating either the number and weights of the transported particles or the mean free paths of the various interaction mechanisms. The considered techniques are 1) splitting and Russian roulette, with the ant colony method as builder of importance maps, 2) exponential transform and interaction-forcing biasing, 3) Woodcock or delta-scattering method, 4) interaction forcing, and 5) proper use of symmetries and combinations of different techniques. Illustrative results from analog simulations (without recourse to variance-reduction) and from variance-reduced simulations of various transport problems are presented.

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“…Our ant colony algorithm applies this kind of adaptive strategy to drive the application of Sp and Rr. The present implementation is similar to the one used in previous works (García-Pareja et al 2007, Carvajal et al 2009, García-Pareja et al 2010a, 2010b, adapted to the specificities of the present problem.…”

Section: Ant Colony Algorithmmentioning

confidence: 99%

“…The numerical coefficients in the definition (7) yield values of the exponent [κ i ] between −5 and 12. Previous experience (García-Pareja et al 2007,Carvajal et al 2009, García-Pareja et al 2010a, 2010b indicates that small variations of those coefficients do not produce significant improvements in the efficiency of the calculation.…”

mentioning

confidence: 99%

Monte Carlo calculation of specific absorbed fractions: variance reduction techniques

et al. 2015

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The purpose of the present work is to calculate specific absorbed fractions using variance reduction techniques and assess the effectiveness of these techniques in improving the efficiency (i.e. reducing the statistical uncertainties) of simulation results in cases where the distance between the source and the target organs is large and/or the target organ is small. The variance reduction techniques of interaction forcing and an ant colony algorithm, which drives the application of splitting and Russian roulette, were applied in Monte Carlo calculations performed with the code penelope for photons with energies from 30 keV to 2 MeV. In the simulations we used a mathematical phantom derived from the well-known MIRD-type adult phantom. The thyroid gland was assumed to be the source organ and urinary bladder, testicles, uterus and ovaries were considered as target organs. Simulations were performed, for each target organ and for photons with different energies, using these variance reduction techniques, all run on the same processor and during a CPU time of 1.5 · 10(5) s. For energies above 100 keV both interaction forcing and the ant colony method allowed reaching relative uncertainties of the average absorbed dose in the target organs below 4% in all studied cases. When these two techniques were used together, the uncertainty was further reduced, by a factor of 0.5 or less. For photons with energies below 100 keV, an adapted initialization of the ant colony algorithm was required. By using interaction forcing and the ant colony algorithm, realistic values of the specific absorbed fractions can be obtained with relative uncertainties small enough to permit discriminating among simulations performed with different Monte Carlo codes and phantoms. The methodology described in the present work can be employed to calculate specific absorbed fractions for arbitrary arrangements, i.e. energy spectrum of primary radiation, phantom model and source and target organs.

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Ant colony algorithm implementation in electron and photon Monte Carlo transport: Application to the commissioning of radiosurgery photon beams

Cited by 6 publications

References 25 publications

A jaw calibration method to provide a homogeneous dose distribution in the matching region when using a monoisocentric beam split technique

A jaw calibration method to provide a homogeneous dose distribution in the matching region when using a monoisocentric beam split technique

Variance-Reduction Methods for Monte Carlo Simulation of Radiation Transport

Monte Carlo calculation of specific absorbed fractions: variance reduction techniques

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