@Article{Knaup2011,
journal="Journal of Contemporary Brachytherapy",
issn="1689-832X",
volume="3",
number="3",
year="2011",
title="Evaluation of the effect of prostate volume change on tumor control probability in LDR brachytherapy",
abstract="  Purpose  : This study evaluates low dose-rate brachytherapy (LDR) prostate plans to determine the biological effect of dose degradation due to prostate volume changes.      Material and methods  : In this study, 39 patients were evaluated. Pre-implant prostate volume was determined using ultrasound. These images were used with the treatment planning system (Nucletron Spot Pro 3.1 ® ) to create treatment plans using  103 Pd seeds. Following the implant, patients were imaged using CT for post-implant dosimetry. From the pre and post-implant DVHs, the biologically equivalent dose and the tumor control probability (TCP) were determined using the biologically effective uniform dose. The model used RBE = 1.75 and α/β = 2 Gy.      Results:   The prostate volume changed between pre and post implant image sets ranged from –8% to 110%. TCP and the mean dose were reduced up to 21% and 56%, respectively. TCP is observed to decrease as the mean dose decreases to the prostate. The post-implant tumor dose was generally observed to decrease, compared to the planned dose. A critical uniform dose of 130 Gy was established. Below this dose, TCP begins to fall-off. It was also determined that patients with a small prostates were more likely to suffer TCP decrease.      Conclusions  : The biological effect of post operative prostate growth due to operative trauma in LDR was evaluated using the concept. The post-implant dose was lower than the planned dose due to an increase of prostate volume post-implant. A critical uniform dose of 130 Gy was determined, below which TCP begun to decline.",
author="Knaup, Courtney
and Mavroidis, Panayiotis
and Stathakis, Sotirios
and Smith, Mark
and Swanson, Gregory
and Papanikolaou, Niko",
pages="125--130",
doi="10.5114/jcb.2011.24818",
url="http://dx.doi.org/10.5114/jcb.2011.24818"
}