Evaluation of brachytherapy lung implant dose distributions from photon‐emitting sources due to tissue heterogeneities

Abstract

The current brachytherapy dose calculation formalism overestimates PTV dose and significantly underestimates doses to bone and healthy tissue. Further investigation using specific brachytherapy source models and patient-based CT datasets as MC input may indicate whether the observed trends can be generalized for low-energy lung brachytherapy dosimetry.

Dosimetric characterization of a new directional low‐dose rate brachytherapy source

“…This work proposes an element‐based approach to characterize the CivaSheet dose distribution, in accordance with previous work by Colonias et al and Yang et al for conventional 125 I and 131 Cs source arrays. In order to do so, the dosimetric characterization of a CivaDot needs to be performed.…”

Air‐kerma strength determination of a new directional 103Pd source

“…More traditional brachytherapy source arrays have been used in interstitial implants, especially for the treatment of nonsmall-cell lung cancer 1,2 and have been shown to result in significant improvements in local recurrence. 3,4 Two examples of these source arrays are 125 I seeds embedded into a vicryl mesh 5 and 131 Cs BrachyMesh arrays 6 commercially produced by IsoRay Medical, Inc. (Richland, WA). The use of planar and directional sources such as the CivaSheet in brachytherapy has been developed on the basis that it can potentially lead to increased normal tissue sparing and an improved therapeutic ratio in contrast to traditional LDR sources.…”

“…The individual elements of traditional LDR 125 I and 131 Cs brachytherapy source arrays 5,6 are calibrated according to the methods of the American Association of Physicists in Medicine (AAPM) Task Group No. 43 Report 9 and its associated Update of AAPM Task Group No.…”

The phylogeny of permanent prostate brachytherapy

“…When Memorial's brachytherapists and physicists empirically adopted a conversion factor of 2 to apply their clinical experience with 222 Rn to dosing with 125 I (without the benefit of radiobiological calculations), they recognized that it was no more than ‘an educated guess and is subject to revision on the basis of further experimental studies and clinical experience’ [28]. There are indications that 144 Gy may not be optimal for prostate cancer [35], and even the historical dose used for permanent lung brachytherapy required adjustment [36, 37]. Should all prostate cancers, regardless of bulk and grade, be treated to the same dose?…”