Article

Monte Carlo techniques in medical radiation physics

Department of Radiation Physics, Karolinska Institute, Stockholm, Sweden.
Physics in Medicine and Biology (Impact Factor: 2.92). 08/1991; 36(7):861-920. DOI: 10.1088/0031-9155/36/7/001
Source: PubMed

ABSTRACT The author's main purpose is to review the techniques and applications of the Monte Carlo method in medical radiation physics since Raeside's review article in 1976. Emphasis is given to applications where proton and/or electron transport in matter is simulated. Some practical aspects of Monte Carlo practice, mainly related to random numbers and other computational details, are discussed in connection with common computing facilities available in hospital environments. Basic aspects of electron and photon transport are reviewed, followed by the presentation of the Monte Carlo codes widely available in the public domain. Applications in different areas of medical radiation physics, such as nuclear medicine, diagnostic X-rays, radiotherapy physics (including dosimetry), and radiation protection, and also microdosimetry and electron microscopy, are presented. Actual and future trends in the field, like Inverse Monte Carlo methods, vectorization of codes and parallel processors calculations are also discussed.

Download full-text

Full-text

Available from: Pedro Andreo, Jul 07, 2015
1 Follower
 · 
252 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: a b s t r a c t In this work, the main components of Siemens ONCORÔ Expression linear accelerator have been modeled using the Monte Carlo code MCNPX. The model thus developed has been used in the validation of the 6 and 15 MV photon beams, applying the phase space technique. The Percentage Depth Dose (PDD), the profiles, and the photon spectrum of the 10 Â 10 cm 2 field have been calculated for both megavoltage beams. The higher emission probability in the low-energy portion of the photon spectrum has been determined for the 6 MV beam, in order to enhance the image of the Cone Beam Computed Tomography with megavoltage beam, using the Flat Panel portal. Results obtained for the Percentage Depth Dose have shown an agreement of better than 1% with the measured values in the regions beyond the build-up, for both beams. The profiles simulated at different depths have shown a good agreement with experimental values, below of the tolerances established. The photon spectrum calculated for the 10 Â 10 cm 2 field show that energies lower 250 keV tend to present a higher probability of emission, especially when the 6 MV beam is considered. This is probably due to the use of low density materials in the target of the linear accelerator.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this work, the main components of Siemens ONCOR� Expression linear accelerator have been modeled using the Monte Carlo code MCNPX. The model thus developed has been used in the validation of the 6 and 15 MV photon beams, applying the phase space technique. The Percentage Depth Dose (PDD), the profiles, and the photon spectrum of the 10 � 10 cm2 field have been calculated for both megavoltage beams. The higher emission probability in the low-energy portion of the photon spectrum has been determined for the 6 MV beam, in order to enhance the image of the Cone Beam Computed Tomography with megavoltage beam, using the Flat Panel portal. Results obtained for the Percentage Depth Dose have shown an agreement of better than 1% with the measured values in the regions beyond the build-up, for both beams. The profiles simulated at different depths have shown a good agreement with experimental values, below of the tolerances established. The photon spectrum calculated for the 10 � 10 cm2 field show that energies lower 250 keV tend to present a higher probability of emission, especially when the 6 MV beam is considered. This is probably due to the use of low density materials in the target of the linear accelerator.
    Progress in Nuclear Energy 07/2013; 70:64-70. DOI:10.1016/j.pnucene.2013.07.013 · 0.88 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: Pineapple is now the third most important tropical fruit in world production after banana and citrus. Phytosanitary irradiation is recognized as a promising alternative treatment to chemical fumigation. However, most of the phytosanitary irradiation studies have dealt with physiochemical properties and its efficacy. Accurate dose calculation is crucial for ensuring proper process control in phytosanitary irradiation. The objective of this study was to optimize phytosanitary irradiation treatment of pineapple in various radiation sources using Monte Carlo simulation. Methods: 3-D geometry and component densities of the pineapple, extracted from CT scan data, were entered into a radiation transport Monte Carlo code (MCNP5) to obtain simulated dose distribution. Radiation energy used for simulation were 2 MeV (low-energy) and 10 MeV (high-energy) for electron beams, 1.25 MeV for gamma-rays, and 5 MeV for X-rays. Results: For low-energy electron beam simulation, electrons penetrated up to 0.75 cm from the pineapple skin, which is good for controlling insect eggs laid just below the fruit surface. For high-energy electron beam simulation, electrons penetrated up to 4.5 cm and the irradiation area occupied 60.2% of the whole area at single-side irradiation and 90.6% at double-side irradiation. For a single-side only gamma- and X-ray source simulation, the entire pineapple was irradiated and dose uniformity ratios (Dmax/Dmin) were 2.23 and 2.19, respectively. Even though both sources had all greater penetrating capability, the X-ray treatment is safer and the gamma-ray treatment is more widely used due to their availability. Conclusions: These results are invaluable for optimizing phytosanitary irradiation treatment planning of pineapple.
    06/2013; 38(2). DOI:10.5307/JBE.2013.38.2.087