Monte Carlo Estimation of Absorbed Dose to Organs in Diagnostic Radiology

Alonso, M. Hernández; Barriuso, T; Mj, Castañeda; Díaz-Caneja, N; Gutiérrez, I.; Jj, Sarmiento; Villar, E. Calvo

doi:10.1097/00004032-199904000-00006

Cited by 6 publications

(3 citation statements)

References 1 publication

(1 reference statement)

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“…In these studies E and energy imparted (ε), which can be reliably used in correlation with E for risk estimation, were calculated from entrance surface dose (ESD) or kerma area product (KAP) using appropriate conversion coefficients provided by other investigators (Persliden and Sandborg 1993, Chapple et al 1994, Hart et al 1996. These coefficients are derived using Monte Carlo (MC) simulation which is a well-established method used in paediatric and non-paediatric radiology for the calculation of H, E and ε (Shrimpton et al 1986, Zankl et al 1989, Drexler et al 1990, Hart et al 1994, Huda and Gkanatsios 1997, Wise et al 1999, Alonso et al 1999, Schimdt et al 2000.…”

Section: Introductionmentioning

confidence: 99%

Radiation risk assessment in neonatal radiographic examinations of the chest and abdomen: a clinical and Monte Carlo dosimetry study

et al. 2006

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Seeking to assess the radiation risk associated with radiological examinations in neonatal intensive care units, thermo-luminescence dosimetry was used for the measurement of entrance surface dose (ESD) in 44 AP chest and 28 AP combined chest-abdominal exposures of a sample of 60 neonates. The mean values of ESD were found to be equal to 44 +/- 16 microGy and 43 +/- 19 microGy, respectively. The MCNP-4C2 code with a mathematical phantom simulating a neonate and appropriate x-ray energy spectra were employed for the simulation of the AP chest and AP combined chest-abdominal exposures. Equivalent organ dose per unit ESD and energy imparted per unit ESD calculations are presented in tabular form. Combined with ESD measurements, these calculations yield an effective dose of 10.2 +/- 3.7 microSv, regardless of sex, and an imparted energy of 18.5 +/- 6.7 microJ for the chest radiograph. The corresponding results for the combined chest-abdominal examination are 14.7 +/- 7.6 microSv (males)/17.2 +/- 7.6 microSv (females) and 29.7 +/- 13.2 microJ. The calculated total risk per radiograph was low, ranging between 1.7 and 2.9 per million neonates, per film, and being slightly higher for females. Results of this study are in good agreement with previous studies, especially in view of the diversity met in the calculation methods.

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Section: Introductionmentioning

confidence: 99%

Radiation risk assessment in neonatal radiographic examinations of the chest and abdomen: a clinical and Monte Carlo dosimetry study

et al. 2006

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“…Among the methods and tools used to determine the skin and, in some instances, organ dose are the use of commercial products such as Diamentor and Pemnet, [1][2][3] dosimeters such as thermoluminescent dosimeters, films, or ionization chambers, [4][5][6][7][8][9] beam data ͑e.g., depth dose, backscatter factor, exposure͒ and/or technique factors, [10][11][12] and Monte Carlo methods. 13,14 Computer programs have also been developed to calculate the dose from diagnostic procedures. 15,16 In this investigation, we used the ADAC Pinnacle treatment planning system to compute the dose within phantoms from kilovoltage x rays and compared the calculations with measurements.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a model‐based treatment planning system for dose computations in the kilovoltage energy range

2000

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The ability to determine dose distribution and calculate organ doses from diagnostic x rays has become increasingly important in recent years because of relatively high doses in interventional radiology and cardiology procedures. In an attempt to determine the dose from both diagnostic and orthovoltage x rays, we have used a commercial treatment planning system (Pinnacle, ADAC Laboratories, Milpitas, CA) to calculate the doses in phantoms from kilovoltage x rays. The planning system's capabilities for dose computation have been extended to lower energies by the addition of energy deposition kernels in the 20-110 keV range and modeling of the 60, 80, 100, and 120 kVp beams using the system. We compared the dose calculated by the system with that measured using thermoluminescent dosimeters (TLDs) placed in various positions within several phantoms. The phantoms consisted of a cubical solid water phantom, the solid water phantom with added lung and bone inhomogeneities, and the Rando anthropomorphic phantom. Using Pinnacle, a treatment plan was generated using CT scans of each of these phantoms and point doses at the positions of TLD chips were calculated. Comparisons of measured and computed values show an average difference of less than 2% within materials of atomic number less than and equal to that of water. The algorithm, however, does not produce accurate results in and around bone inhomogeneities and underestimates attenuation of x rays by bone by an average of 145%. A modification to the CT number-to-density conversion table used by the system resulted in significant improvements in the dose calculated to points beyond bone.

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“…The forecast dose can be verified by the placement of a calibrated thermoluminescent dosimeter (TLD) at the same location. Phantom modelling techniques include the use of mathematical inequalities (Snyder et al 1969, Tung and Tsai 1999, Alonso et al 1999, volume elements (Caon et al 1997, Zubal andHarrel 1992) and anatomical atlases (Ranniko et al 1997). Phantom models that accurately portray the anatomical features of the actual phantom ensure that avoidable discrepancies do not occur between the measurements and simulations of absorbed dose.…”

Section: Introductionmentioning

confidence: 99%

Diagnostic x-ray dosimetry using Monte Carlo simulation

et al. 2002

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An Electron Gamma Shower version 4 (EGS4) based user code was developed to simulate the absorbed dose in humans during routine diagnostic radiological procedures. Measurements of absorbed dose using thermoluminescent dosimeters (TLDs) were compared directly with EGS4 simulations of absorbed dose in homogeneous, heterogeneous and anthropomorphic phantoms. Realistic voxel-based models characterizing the geometry of the phantoms were used as input to the EGS4 code. The voxel geometry of the anthropomorphic Rando phantom was derived from a CT scan of Rando. The 100 kVp diagnostic energy x-ray spectra of the apparatus used to irradiate the phantoms were measured, and provided as input to the EGS4 code. The TLDs were placed at evenly spaced points symmetrically about the central beam axis, which was perpendicular to the cathode-anode x-ray axis at a number of depths. The TLD measurements in the homogeneous and heterogenous phantoms were on average within 7% of the values calculated by EGS4. Estimates of effective dose with errors less than 10% required fewer numbers of photon histories (1 x 10(7)) than required for the calculation of dose profiles (1 x 10(9)). The EGS4 code was able to satisfactorily predict and thereby provide an instrument for reducing patient and staff effective dose imparted during radiological investigations.

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Monte Carlo Estimation of Absorbed Dose to Organs in Diagnostic Radiology

Cited by 6 publications

References 1 publication

Radiation risk assessment in neonatal radiographic examinations of the chest and abdomen: a clinical and Monte Carlo dosimetry study

Radiation risk assessment in neonatal radiographic examinations of the chest and abdomen: a clinical and Monte Carlo dosimetry study

Evaluation of a model‐based treatment planning system for dose computations in the kilovoltage energy range

Diagnostic x-ray dosimetry using Monte Carlo simulation

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