PURPOSE: To develop a method for treatment planning and optimization of magnetic resonance imaging (MRI)-assisted gynecologic brachytherapy that includes biologically weighted total dose constraints. METHODS AND MATERIALS: The applied algorithm is based on the linear-quadratic model and includes dose, dose rate, and fractionation of the whole radiotherapy setting, consisting of external beam therapy plus high-dose-rate (HDR), low-dose-rate (LDR) or pulsed-dose rate (PDR) brachytherapy. Biologically effective doses (BED) are converted to more familiar isoeffective (equivalent) doses in 2-Gy fractions. For individual treatment planning of each brachytherapy fraction, the algorithm calculates the physical dose per brachytherapy fraction that corresponds to a predefined isoeffective total dose constraint. Achieved target dose and sparing of organs at risk of already delivered brachytherapy fractions are incorporated. RESULTS: Since implementation for use in clinical routine in 2001, MRI assisted treatment plans of 216 gynecologic patients (161 HDR, 55 PDR brachytherapy) were prospectively optimized taking into account isoeffective dose-volume histogram-based total dose constraints for high-risk clinical target volume (HR CTV) and organs at risk (bladder, rectum, sigmoid). The algorithm is implemented in a spreadsheet and the procedure is fast and efficient. An uncertainty analysis of the isoeffective total doses based on variations of tissue parameters shows that confidence intervals are larger for PDR compared with HDR brachytherapy. For common treatment schedules, overall uncertainties of high-risk clinical target volume and organs at risk are within 8 Gy, except for the bladder when using the PDR technique. CONCLUSION: The presented method to respect total dose constraints is reliable and efficient and an essential tool when aiming to increase local control and minimize side effects.
PURPOSE: To develop a method for treatment planning and optimization of magnetic resonance imaging (MRI)-assisted gynecologic brachytherapy that includes biologically weighted total dose constraints. METHODS AND MATERIALS: The applied algorithm is based on the linear-quadratic model and includes dose, dose rate, and fractionation of the whole radiotherapy setting, consisting of external beam therapy plus high-dose-rate (HDR), low-dose-rate (LDR) or pulsed-dose rate (PDR) brachytherapy. Biologically effective doses (BED) are converted to more familiar isoeffective (equivalent) doses in 2-Gy fractions. For individual treatment planning of each brachytherapy fraction, the algorithm calculates the physical dose per brachytherapy fraction that corresponds to a predefined isoeffective total dose constraint. Achieved target dose and sparing of organs at risk of already delivered brachytherapy fractions are incorporated. RESULTS: Since implementation for use in clinical routine in 2001, MRI assisted treatment plans of 216 gynecologic patients (161 HDR, 55 PDR brachytherapy) were prospectively optimized taking into account isoeffective dose-volume histogram-based total dose constraints for high-risk clinical target volume (HR CTV) and organs at risk (bladder, rectum, sigmoid). The algorithm is implemented in a spreadsheet and the procedure is fast and efficient. An uncertainty analysis of the isoeffective total doses based on variations of tissue parameters shows that confidence intervals are larger for PDR compared with HDR brachytherapy. For common treatment schedules, overall uncertainties of high-risk clinical target volume and organs at risk are within 8 Gy, except for the bladder when using the PDR technique. CONCLUSION: The presented method to respect total dose constraints is reliable and efficient and an essential tool when aiming to increase local control and minimize side effects.
Authors: M Dolezel; K Odrazka; J Vanasek; T Kohlova; T Kroulik; K Kudelka; D Spitzer; M Mrklovsky; M Tichy; J Zizka; L Jalcova Journal: Br J Radiol Date: 2011-09 Impact factor: 3.039
Authors: P Georg; A Boni; A Ghabuous; G Goldner; M P Schmid; D Georg; R Pötter; W Dörr Journal: Strahlenther Onkol Date: 2013-05-25 Impact factor: 3.621
Authors: Richard Pötter; Petra Georg; Johannes C A Dimopoulos; Magdalena Grimm; Daniel Berger; Nicole Nesvacil; Dietmar Georg; Maximilian P Schmid; Alexander Reinthaller; Alina Sturdza; Christian Kirisits Journal: Radiother Oncol Date: 2011-08-05 Impact factor: 6.280
Authors: Radovan Vojtíšek; Petr Hošek; Emília Sukovská; Petra Kovářová; Jan Baxa; Jiří Ferda; Jindřich Fínek Journal: Strahlenther Onkol Date: 2022-01-21 Impact factor: 4.033
Authors: Willemien van den Bos; Sushil Beriwal; Laura Velema; Astrid A C de Leeuw; Christel N Nomden; Ina-M Jürgenliemk-Schulz Journal: J Contemp Brachytherapy Date: 2014-04-03