BACKGROUND AND PURPOSE: To describe the implementation and to evaluate the results of direct segment aperture optimization using the segment outline and weight adapting tool (SOWAT) in intensity-modulated radiotherapy (IMRT) for prostate cancer. PATIENTS AND METHODS: 14 consecutive, unselected patients with localized prostate cancer were entered in a planning study comparing IMRT without and with the use of SOWAT. The clinical target volume (CTV) consisted of the prostate and seminal vesicles in all cases. To create the planning target volume (PTV), a three-dimensional anisotropic margin (10 mm in craniocaudal direction, 7 mm in both other directions) was used. To compare both plans, physical as well as biological endpoints were considered. RESULTS: Considering the CTV, SOWAT resulted in a significantly higher minimal dose together with a higher dose to 95% (D(95)) and 90% (D(90)) of the CTV volume (p < 0.05; Figure 2). Target dose homogeneity was significantly improved (p < 0.001). Tumor control probability (TCP) was significantly increased (p < 0.05). Considering the PTV, D(90) was significantly increased (p < 0.05). Target dose homogeneity was significantly improved (p < 0.05; Figure 1). For rectum, the volumes receiving 50 Gy (R(vol50)), 60 Gy (R(vol60)), or 65 Gy (R(vol65)) as well as the mean dose were significantly lowered after SOWAT (p = 0.0001; Figure 3). Rectal normal tissue complication probability (NTCP) was significantly lower after SOWAT (p = 0.005). Probability of uncomplicated local control (P+) was significantly higher after SOWAT (p < 0.0001). CONCLUSION: SOWAT is a powerful planning tool to increase the therapeutic ratio of IMRT for prostate cancer. It leaves the delivery time unchanged, so that treatments can still be delivered within a time slot of 8 min.
BACKGROUND AND PURPOSE: To describe the implementation and to evaluate the results of direct segment aperture optimization using the segment outline and weight adapting tool (SOWAT) in intensity-modulated radiotherapy (IMRT) for prostate cancer. PATIENTS AND METHODS: 14 consecutive, unselected patients with localized prostate cancer were entered in a planning study comparing IMRT without and with the use of SOWAT. The clinical target volume (CTV) consisted of the prostate and seminal vesicles in all cases. To create the planning target volume (PTV), a three-dimensional anisotropic margin (10 mm in craniocaudal direction, 7 mm in both other directions) was used. To compare both plans, physical as well as biological endpoints were considered. RESULTS: Considering the CTV, SOWAT resulted in a significantly higher minimal dose together with a higher dose to 95% (D(95)) and 90% (D(90)) of the CTV volume (p < 0.05; Figure 2). Target dose homogeneity was significantly improved (p < 0.001). Tumor control probability (TCP) was significantly increased (p < 0.05). Considering the PTV, D(90) was significantly increased (p < 0.05). Target dose homogeneity was significantly improved (p < 0.05; Figure 1). For rectum, the volumes receiving 50 Gy (R(vol50)), 60 Gy (R(vol60)), or 65 Gy (R(vol65)) as well as the mean dose were significantly lowered after SOWAT (p = 0.0001; Figure 3). Rectal normal tissue complication probability (NTCP) was significantly lower after SOWAT (p = 0.005). Probability of uncomplicated local control (P+) was significantly higher after SOWAT (p < 0.0001). CONCLUSION: SOWAT is a powerful planning tool to increase the therapeutic ratio of IMRT for prostate cancer. It leaves the delivery time unchanged, so that treatments can still be delivered within a time slot of 8 min.
Authors: Martin Dolezel; Karel Odrazka; Miloslava Vaculikova; Jaroslav Vanasek; Jana Sefrova; Petr Paluska; Milan Zouhar; Jan Jansa; Zuzana Macingova; Lida Jarosova; Milos Brodak; Petr Moravek; Igor Hartmann Journal: Strahlenther Onkol Date: 2010-03-26 Impact factor: 3.621
Authors: Gregor Goldner; Valentin Bombosch; Hans Geinitz; Gerd Becker; Stefan Wachter; Stefan Glocker; Frank Zimmermann; Natascha Wachter-Gerstner; Andrea Schrott; Michael Bamberg; Michael Molls; Horst Feldmann; Richard Pötter Journal: Strahlenther Onkol Date: 2009-02-25 Impact factor: 3.621