Limits...
Monte Carlo-based investigation of water-equivalence of solid phantoms at (137)Cs energy.

Vishwakarma RS, Selvam TP, Sahoo S, Mishra S, Chourasiya G - J Med Phys (2013)

Bottom Line: The investigation reveals that solid water, virtual water, and RW1 phantoms are water equivalent up to 15 cm from the source.Phantom materials such as plastic water, PMMA, and polystyrene phantom materials are water equivalent up to 10 cm.At 15 cm from the source, the phantom scatter corrections are 1.035, 1.050, and 0.949 for the phantoms PMMA, plastic water, and polystyrene, respectively.

View Article: PubMed Central - PubMed

Affiliation: Radiological Physics and Advisory Division, Health, Safety and Environment Group, Bhabha Atomic Research Centre, Anushaktinagar, Mumbai, Maharastra, India.

ABSTRACT
Investigation of solid phantom materials such as solid water, virtual water, plastic water, RW1, polystyrene, and polymethylmethacrylate (PMMA) for their equivalence to liquid water at (137)Cs energy (photon energy of 662 keV) under full scatter conditions is carried out using the EGSnrc Monte Carlo code system. Monte Carlo-based EGSnrc code system was used in the work to calculate distance-dependent phantom scatter corrections. The study also includes separation of primary and scattered dose components. Monte Carlo simulations are carried out using primary particle histories up to 5 × 10(9) to attain less than 0.3% statistical uncertainties in the estimation of dose. Water equivalence of various solid phantoms such as solid water, virtual water, RW1, PMMA, polystyrene, and plastic water materials are investigated at (137)Cs energy under full scatter conditions. The investigation reveals that solid water, virtual water, and RW1 phantoms are water equivalent up to 15 cm from the source. Phantom materials such as plastic water, PMMA, and polystyrene phantom materials are water equivalent up to 10 cm. At 15 cm from the source, the phantom scatter corrections are 1.035, 1.050, and 0.949 for the phantoms PMMA, plastic water, and polystyrene, respectively.

No MeSH data available.


Related in: MedlinePlus

The dependence of primary, scattered, and total dose in water multiplied by 4πr2 per unit mean energy versus radial distance r from 137Cs point source in water
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3958994&req=5

Figure 6: The dependence of primary, scattered, and total dose in water multiplied by 4πr2 per unit mean energy versus radial distance r from 137Cs point source in water

Mentions: The scatter component of the absorbed dose, Ds (r) was obtained by subtracting Dp (r) from the EDKnrc-calculated total dose. The scatter-to-primary ratio Ds (r)/Dp (r) helps in understanding the differences in the scattering of photons in different phantom materials. This ratio is plotted in Figure 5 for the investigated phantom materials. Although the absolute values of Ds (r) decrease with r, the ratio Ds (r)/Dp (r) increases because of the inverse square fall of Dp (r). Table 4 presents the distance at which Ds (r) equals Dp (r) for the investigated phantom materials. Figure 6 presents dose per unit energy multiplied by 4πr2 per source photon as a function of r from the 137Cs point source.


Monte Carlo-based investigation of water-equivalence of solid phantoms at (137)Cs energy.

Vishwakarma RS, Selvam TP, Sahoo S, Mishra S, Chourasiya G - J Med Phys (2013)

The dependence of primary, scattered, and total dose in water multiplied by 4πr2 per unit mean energy versus radial distance r from 137Cs point source in water
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3958994&req=5

Figure 6: The dependence of primary, scattered, and total dose in water multiplied by 4πr2 per unit mean energy versus radial distance r from 137Cs point source in water
Mentions: The scatter component of the absorbed dose, Ds (r) was obtained by subtracting Dp (r) from the EDKnrc-calculated total dose. The scatter-to-primary ratio Ds (r)/Dp (r) helps in understanding the differences in the scattering of photons in different phantom materials. This ratio is plotted in Figure 5 for the investigated phantom materials. Although the absolute values of Ds (r) decrease with r, the ratio Ds (r)/Dp (r) increases because of the inverse square fall of Dp (r). Table 4 presents the distance at which Ds (r) equals Dp (r) for the investigated phantom materials. Figure 6 presents dose per unit energy multiplied by 4πr2 per source photon as a function of r from the 137Cs point source.

Bottom Line: The investigation reveals that solid water, virtual water, and RW1 phantoms are water equivalent up to 15 cm from the source.Phantom materials such as plastic water, PMMA, and polystyrene phantom materials are water equivalent up to 10 cm.At 15 cm from the source, the phantom scatter corrections are 1.035, 1.050, and 0.949 for the phantoms PMMA, plastic water, and polystyrene, respectively.

View Article: PubMed Central - PubMed

Affiliation: Radiological Physics and Advisory Division, Health, Safety and Environment Group, Bhabha Atomic Research Centre, Anushaktinagar, Mumbai, Maharastra, India.

ABSTRACT
Investigation of solid phantom materials such as solid water, virtual water, plastic water, RW1, polystyrene, and polymethylmethacrylate (PMMA) for their equivalence to liquid water at (137)Cs energy (photon energy of 662 keV) under full scatter conditions is carried out using the EGSnrc Monte Carlo code system. Monte Carlo-based EGSnrc code system was used in the work to calculate distance-dependent phantom scatter corrections. The study also includes separation of primary and scattered dose components. Monte Carlo simulations are carried out using primary particle histories up to 5 × 10(9) to attain less than 0.3% statistical uncertainties in the estimation of dose. Water equivalence of various solid phantoms such as solid water, virtual water, RW1, PMMA, polystyrene, and plastic water materials are investigated at (137)Cs energy under full scatter conditions. The investigation reveals that solid water, virtual water, and RW1 phantoms are water equivalent up to 15 cm from the source. Phantom materials such as plastic water, PMMA, and polystyrene phantom materials are water equivalent up to 10 cm. At 15 cm from the source, the phantom scatter corrections are 1.035, 1.050, and 0.949 for the phantoms PMMA, plastic water, and polystyrene, respectively.

No MeSH data available.


Related in: MedlinePlus