Photon Dose Enhancement Ratio at the Transition Region of Dissimilar Media

Maan S. Al-Arif

Abstract


Accurate measurement was carried out for the dose gradient in Teflon irradiated with filtered X-ray spectra having effective energies of 40 keV and 55 keV when in contact with aluminum, titanium, copper, and tin. At low photon energies, the interface region is only extended for about 10 microns from the interface, therefore, ultra-thin LiF/Teflon discs of the order of 3 microns thick was developed and used to measure directly the dose gradient in Teflon. Due to the relatively large slope of the depth dose curves near the interfaces, a displacement correction factor was introduced to determine the effective measuring point of the detector. A fitting exponential formula is suggested and used to estimate the dose gradient for Bone-Teflon interface. The interface dose for Bone-Teflon is 3.8 times the equilibrium dose at 70 KV, while it is about 3.1 at 100 KV.

Keywords


Buildup dose, effective energy, radiation, transition region

Full Text:

PDF

References


Al-Arif, M.S., 2013a. The Effective Measuring Point of Thermoluminescent Detector at the Build-up Region. Journal of Natural Sciences and Mathematics, PK, 52(1), pp.1-7.

Al-Arif, M.S., 2013b. Unity Energy Response Using CaSO4:DY/Teflon. ARO, The Scientific Journal of Koya University, 1(1), pp.14-16. Retrieved from http://dx.doi.org/10.14500/aro.10026.

Chandra, P.J., Johnson, D., Vidyasagar, P. B. , Schreiner, L.J, 2010. Dosimetry of interface region near closed air cavities for Co-60, 6 MV and 15 MV photon beams using Monte Carlo simulations. J Med Phys, 39(2), pp.73-80.

Das, I.J., Kassaee, A., Verhaegen, F. and Moskvin, V.P., 2001. Measurements and Monte Carlo simulations of low-energy photon beams. Rad Phys and Chemistry, 61(3), pp. 593-595.

Joshi, C. P., Darko, J., Vidyasagar, P. B. and Schreiner, L.J., 2010. Dosimetry of interface region near closed air cavities for Co-60, 6 MV and 15 MV photon beams using Monte Carlo simulations. J Med Phys, 35(2), pp.73-80.

Kinhikar, R.A, Tambe, C.M., Patil, K., Mandavkar, M., Deshpande, D.D., Gujjalanavar, R., Yadav, P. and Budrukkar, A, 2014. Estimation of dose enhancement to soft tissue due to backscatter radiation near metal interfaces during head and neck radiotherapy- A phantom dosimetric study with radiochromic film. J Med Phys, 39(1), pp.40-3.

Li XA, Yu C. and Holmes, T., 2000. A systematic evaluation of air cavity dose perturbation in megavoltage X-ray beams. Med Phys, (27), pp.1011-7.

Nicopoulou-Karayianni, K., Koligliatis, T., Donta-Bakogianni, C., Karayiannis, A. and Litsas, J., 2003. Radiation absorbed doses at compact bone-titanium interfaces in diagnostic radiography: a Monte Carlo approach. Dentomaxillofac Radiol, 32(5), pp.327-32.

Shiu, A.S. and Hogstrom, K.R., 1991. Dose in Bone and Tissue near Bone-Tissue interface from electron beam. Int J Radiat Oncol Biol Phys., 21(3), pp.695-702.




DOI: http://dx.doi.org/10.14500/aro.10046
View Counter: Abstract | 366 | and PDF | 159 |

Article Metrics

Metrics Loading ...

Metrics powered by PLOS ALM

Refbacks

  • There are currently no refbacks.


Copyright (c) 2016 Maan S. Al-Arif

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

  
 


ARO Journal is an OAJ supported by Koya University, it has no article submission/processing charges (APCs).
© 2013-2020, Koya University is a public University accredited by the Ministry of Higher Education and Scientific Research, KRG - F.R. Iraq.