Examination of general cavity theory for magnesium and titanium doped lithium fluoride (TLD-100) of varying thicknesses in bone and lung Neslihan Sarigul a , Murat Surucu b , Chet Reft c , Zehra Yegingil d , Bulent Aydogan c, * a Institute of Nuclear Science, Hacettepe University, 06532 Ankara, Turkey b Department of Radiation Oncology, Loyola University Medical Center, Maywood, IL, USA c Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, USA d Art and Science Faculty, Physics Department, Cukurova University, 01330 Adana, Turkey highlights  Investigated the accuracy of Burlin cavity theory for clinically used thin TLDS.  Provided values of d for Burlin cavity theory calculations in bone and lung.  Provided MC simulated f ðÞ TLD med to be used by thse radiation measurement community.  MC method can be successfully used instead of stheoretical calculations of f ðÞ TLD med . article info Article history: Received 1 April 2015 Received in revised form 13 June 2016 Accepted 15 August 2016 Available online 18 August 2016 Keywords: Burlin cavity theory Radiation dose TLD Bone Lung Monte Carlo (MC) Inhomogeneity abstract Purpose: To evaluate the accuracy of Burlin cavity theory for TLDs in bone and lung, the two most relevant heterogeneities in radiological physics. Methods: Theoretical calculations and Monte Carlo (MC) simulations of dose to TLD to dose to medium correction factor, ðf Þ TLD med , were performed and compared in bone and lung. MC simulations included virtual irradiation of TLDs with varying thicknesses (0.015, 0.038, and 0.089 cm) in bone, lung, and water phantoms. Theoretical calculation of Burlin cavity theory requires calculation of fractional dose contri- bution from photon interactions (d) from mass effective attenuation coefficient (b) and average path length of electrons penetrating in the cavity from the wall (g). Different theoretical formulations of g and b were used to calculate 18 different values for d and ðf Þ TLD med . Further, the impact of mean energy approximation used in theoretical calculations was evaluated using full spectrum MC simulations. Results: While the values of d differed as much as by a factor of 2, ðf Þ TLD med agreed well (SD ¼ 0.1%) in water, bone and lung. The TLD thickness ranging 0.015e0.089 cm was not a significant factor (SD ¼ 0.2%). Dose correction factors calculated using mean energy approximation agreed within the 2% with full spectrum MC simulations. Uncertainty associated with theoretical calculation of ðf Þ TLD med was 7.2% compare to 0.5% with MC simulation. Conclusion: The ðf Þ TLD med calculated with Burlin theory agreed well with MC results for 6 MV photon beam. Nevertheless, the difficulty and the ambiguity in the determination of b and g in a given medium and the energy spectrum under investigation limited the theoretical calculations and resulted in large uncer- tainty. This study suggests the use of MC for easy and accurate estimation of ðf Þ TLD med , which is required in radiological applications to convert TLD measured dose to dose in medium. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Detectors often constructed of a different material than the medium in which they are used to measure dose thereby forming a cavity (Mobit et al., 1997). The relationship between the absorbed * Corresponding author. 5758 S Maryland Ave, MC9006, Chicago, IL 60637, USA. E-mail addresses: nsarigul@hacettepe.edu.tr (N. Sarigul), msurucu@lumc.edu (M. Surucu), creft@radonc.uchicago.edu (C. Reft), zehra@cukurova.edu.tr (Z. Yegingil), baydogan@uchicago.edu (B. Aydogan). Contents lists available at ScienceDirect Radiation Measurements journal homepage: www.elsevier.com/locate/radmeas http://dx.doi.org/10.1016/j.radmeas.2016.08.005 1350-4487/© 2016 Elsevier Ltd. All rights reserved. Radiation Measurements 94 (2016) 1e7