title: Determination of surface dose rate of indigenous (32)P patch brachytherapy source by experimental and Monte Carlo methods.
abstract: Isotope production and Application Division of Bhabha Atomic Research Center developed (32)P patch sources for treatment of superficial tumors. Surface dose rate of a newly developed (32)P patch source of nominal diameter 25 mm was measured experimentally using standard extrapolation ionization chamber and Gafchromic EBT film. Monte Carlo model of the (32)P patch source along with the extrapolation chamber was also developed to estimate the surface dose rates from these sources. The surface dose rates to tissue (cGy/min) measured using extrapolation chamber and radiochromic films are 82.03±4.18 (k=2) and 79.13±2.53 (k=2) respectively. The two values of the surface dose rates measured using the two independent experimental methods are in good agreement to each other within a variation of 3.5%. The surface dose rate to tissue (cGy/min) estimated using the MCNP Monte Carlo code works out to be 77.78±1.16 (k=2). The maximum deviation between the surface dose rates to tissue obtained by Monte Carlo and the extrapolation chamber method is 5.2% whereas the difference between the surface dose rates obtained by radiochromic film measurement and the Monte Carlo simulation is 1.7%. The three values of the surface dose rates of the (32)P patch source obtained by three independent methods are in good agreement to one another within the uncertainties associated with their measurements and calculation. This work has demonstrated that MCNP based electron transport simulations are accurate enough for determining the dosimetry parameters of the indigenously developed (32)P patch sources for contact brachytherapy applications.
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, CTCRS, Anushaktinagar, Mumbai 400094, India. Electronic address: sktomar1@rediffmail.com.
authors.forename: Sudhir
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Radiation Safety Systems Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
authors.forename: P
authors.initials: P
authors.lastname: Srinivasan
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, CTCRS, Anushaktinagar, Mumbai 400094, India.
authors.forename: S D
authors.initials: SD
authors.lastname: Sharma
authors.affiliation: Isotope Production & Applications Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
authors.forename: Sanjay Kumar
authors.initials: SK
authors.lastname: Saxena
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, CTCRS, Anushaktinagar, Mumbai 400094, India.
authors.forename: A K
authors.initials: AK
authors.lastname: Bakshi
authors.affiliation: Isotope Production & Applications Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Dash
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, CTCRS, Anushaktinagar, Mumbai 400094, India.
authors.forename: D A R
authors.initials: DA
authors.lastname: Babu
authors.affiliation: Health Safety and Environment Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
authors.forename: D N
authors.initials: DN
authors.lastname: Sharma
mesh_terms: D001458:Bandages; D001918:Brachytherapy / Q000295:instrumentation* / Q000379:methods; D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D015233:Models, Statistical; D009010:Monte Carlo Method; D010761:Phosphorus Radioisotopes / Q000032:analysis / Q000627:therapeutic use*; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods*; D019275:Radiopharmaceuticals / Q000032:analysis / Q000627:therapeutic use; D011879:Radiotherapy Dosage; D012867:Skin / Q000528:radiation effects*; D013499:Surface Properties
chemical_list: D010761:Phosphorus Radioisotopes; D019275:Radiopharmaceuticals
keywords: (32)P patch source; Brachytherapy; Extrapolation chamber; Monte Carlo simulation; Radiochromic film