TY - JOUR
T1 - Time-resolved in vivo dosimetry for source tracking in brachytherapy
AU - Johansen, Jacob Graversen
AU - Rylander, Susanne
AU - Buus, Simon
AU - Bentzen, Lise
AU - Hokland, Steffen Bjerre
AU - Søndergaard, Christian Skou
AU - With, Anders Karl Mikael
AU - Kertzscher, Gustavo
AU - Tanderup, Kari
N1 - Publisher Copyright:
© 2017 American Brachytherapy Society
PY - 2018/1
Y1 - 2018/1
N2 - Purpose The purpose of this article is to demonstrate that brachytherapy source tracking can be realized with in vivo dosimetry. This concept could enable real-time treatment monitoring. Methods In vivo dosimetry was incorporated in the clinical routine during high-dose-rate prostate brachytherapy at Aarhus University Hospital. The dosimetry was performed with a radioluminescent crystal positioned in a dedicated brachytherapy needle in the prostate. The dose rate was recorded every 50–100 ms during treatment and analyzed retrospectively. The measured total delivered dose and dose rates for each dwell position with dwell times >0.7 s were compared with expected values. Furthermore, the distance between the source and dosimeter, which was derived from the measured dose rates, was compared with expected values. The measured dose rate pattern in each needle was used to determine the most likely position of the needle relative to the dosimeter. Results In total, 305 needles and 3239 dwell positions were analyzed based on 20 treatments. The measured total doses differed from the expected values by −4.7 ± 8.4% (1SD) with range (−17% to 12%). It was possible to determine needle shifts for 304 out of 305 needles. The mean radial needle shift between imaging and treatment was 0.2 ± 1.1 mm (1SD), and the mean longitudinal shift was 0.3 ± 2.0 mm (1SD). Conclusion Time-resolved in vivo dosimetry can be used to provide geometric information about the treatment progression of afterloading brachytherapy. This information may provide a clear indication of errors and uncertainties during a treatment and, therefore, enables real-time treatment monitoring.
AB - Purpose The purpose of this article is to demonstrate that brachytherapy source tracking can be realized with in vivo dosimetry. This concept could enable real-time treatment monitoring. Methods In vivo dosimetry was incorporated in the clinical routine during high-dose-rate prostate brachytherapy at Aarhus University Hospital. The dosimetry was performed with a radioluminescent crystal positioned in a dedicated brachytherapy needle in the prostate. The dose rate was recorded every 50–100 ms during treatment and analyzed retrospectively. The measured total delivered dose and dose rates for each dwell position with dwell times >0.7 s were compared with expected values. Furthermore, the distance between the source and dosimeter, which was derived from the measured dose rates, was compared with expected values. The measured dose rate pattern in each needle was used to determine the most likely position of the needle relative to the dosimeter. Results In total, 305 needles and 3239 dwell positions were analyzed based on 20 treatments. The measured total doses differed from the expected values by −4.7 ± 8.4% (1SD) with range (−17% to 12%). It was possible to determine needle shifts for 304 out of 305 needles. The mean radial needle shift between imaging and treatment was 0.2 ± 1.1 mm (1SD), and the mean longitudinal shift was 0.3 ± 2.0 mm (1SD). Conclusion Time-resolved in vivo dosimetry can be used to provide geometric information about the treatment progression of afterloading brachytherapy. This information may provide a clear indication of errors and uncertainties during a treatment and, therefore, enables real-time treatment monitoring.
KW - Dose rate measurement
KW - HDR brachytherapy
KW - In vivo dosimetry
KW - Prostate cancer
KW - Source tracking
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U2 - 10.1016/j.brachy.2017.08.009
DO - 10.1016/j.brachy.2017.08.009
M3 - Article
C2 - 28943129
AN - SCOPUS:85029689696
SN - 1538-4721
VL - 17
SP - 122
EP - 132
JO - Brachytherapy
JF - Brachytherapy
IS - 1
ER -