title: Computation of relative dose distribution and effective transmission around a shielded vaginal cylinder with 192Ir HDR source using MCNP4B.
abstract: The present work is primarily focused on the estimation of relative dose distribution and effective transmission around a shielded vaginal cylinder with an 192Ir source using the Monte Carlo technique. The MCNP4B code was used to evaluate the dose distribution around a tungsten shielded vaginal cylinder as a function of thickness and angular shielding. The dose distribution and effective transmission of 192Ir by 0.8 cm thickness tungsten were also compared with that for gold and lead. Dose distributions were evaluated for different distances starting from 1.35 cm to 10.15 cm from the center of the cylinder. Dose distributions were also evaluated sequentially from 0 degrees to 180 degrees for every 5 degrees interval. Studies show that all the shielding material at 0.8 cm thickness contribute tolerable doses to normal tissues and also protect the critical organs such as the rectum and bladder. However, the computed dose values are in good agreement with the reported experimental values. It was also inferred that the higher the shielding angles, the more the protection of the surrounding tissues. Among the three shielding materials, gold has been observed to have the highest attenuation and hence contribute lowest transmission in the shielded region. Depending upon the shielding angle and thickness, it is possible to predict the dose distribution using the MCNP4B code. In order to deliver the higher dose to the unshielded region, lead may be considered as the shielding material and further it is highly economic over other materials.
authors.affiliation: Division of Medical Physics and Lasers, Department of Physics, Anna University, Chennai 600 025, India.
authors.forename: Chandra Sekaran
authors.initials: CS
authors.lastname: Sureka
authors.forename: Prakasarao
authors.initials: P
authors.lastname: Aruna
authors.forename: Singaravelu
authors.initials: S
authors.lastname: Ganesan
authors.forename: Chirayath Sunil
authors.initials: CS
authors.lastname: Sunny
authors.forename: Kamatam Venkata
authors.initials: KV
authors.lastname: Subbaiah
mesh_terms: D005260:Female; D006801:Humans; D009010:Monte Carlo Method; D011835:Radiation Protection / Q000191:economics / Q000295:instrumentation / Q000379:methods*; D011874:Radiometry / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012007:Rectum / Q000293:injuries / Q000528:radiation effects; D012016:Reference Values; D012062:Relative Biological Effectiveness; D018570:Risk Assessment; D012307:Risk Factors; D001743:Urinary Bladder / Q000293:injuries / Q000528:radiation effects; D014621:Vagina / Q000293:injuries / Q000528:radiation effects; D014625:Vaginal Neoplasms / Q000532:radiotherapy*