MONTE CARLO-BASED INVESTIGATION OF MICRODOSIMETRIC DISTRIBUTION OF HIGH ENERGY BRACHYTHERAPY SOURCES.
Radiat Prot Dosimetry
; 187(1): 115-128, 2019 Dec 31.
Article
in En
| MEDLINE
| ID: mdl-31165891
ABSTRACT
FLUKA-based Monte Carlo calculations were carried out to study microdosimetric distributions in air and in water for encapsulated high energy brachytherapy sources (60Co, 137Cs, 192Ir and 169Yb) by simulating a Tissue Equivalent Proportional Counter (Model LET1/2) having sensitive diameter of 1. 27 cm for a site size of 1 µm. The study also included microdosimetric distributions of bare sources. When the sources are in air, for a given source, the source geometry does not affect the y¯F and y¯D values significantly. When the encapsulated 192Ir, 137Cs and 60Co sources are in water, y¯F and y¯D values increase with distance in water which is due to degradation in the energy of photons. Using the calculated values of y¯D, relative biological effectiveness (RBE) was obtained for the investigated sources. When 60Co, 137Cs and 192Ir sources are in water, RBE increases from 1.03 ± 0.01 to 1.17 ± 0.01, 1.24 ± 0.01 to 1.46 ± 0.02 and 1.50 ± 0.01 to 1.75 ± 0.03, respectively, when the distance was increased from 3-15 cm, whereas for 169Yb, RBE is about 2, independent of distance in water.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Ytterbium
/
Brachytherapy
/
Iridium Radioisotopes
/
Cesium Radioisotopes
/
Monte Carlo Method
/
Cobalt Radioisotopes
/
Phantoms, Imaging
Type of study:
Health_economic_evaluation
Limits:
Humans
Language:
En
Journal:
Radiat Prot Dosimetry
Year:
2019
Document type:
Article