The Experts below are selected from a list of 1353 Experts worldwide ranked by ideXlab platform

Lars Fokdal - One of the best experts on this subject based on the ideXlab platform.

  • impact of changes in bladder and Rectal filling volume on organ motion and dose distribution of the bladder in radiotherapy for urinary bladder cancer
    International Journal of Radiation Oncology Biology Physics, 2004
    Co-Authors: Lars Fokdal, Henriette Honore, Morten Hoyer, Peter Meldgaard, Kirsten Fode, Hans Von Der Maase
    Abstract:

    PURPOSE: To determine the impact of filling volume changes of the urinary bladder and rectum on organ motion and dose distribution of the bladder and rectum during radical radiotherapy for bladder cancer and to calculate the internal margins to secure target coverage. METHODS AND MATERIALS: In 15 patients with muscle-invasive bladder cancer, a planning CT scan was performed with a bladder and Rectal Catheter, followed by three immediate CT scans with various filling of the urinary bladder and rectum. After 20 fractions, a fifth CT scan, without catherization, was performed. In each CT study, the bladder and rectum volumes were delineated and matched to the planning CT scan to measure the organ motion and calculate internal margins. These margins were compared with an isotropic standard margin of 2 cm. Dose-volume histograms were analyzed to describe the dose distribution in the bladder and rectum corresponding to various filling volumes. RESULTS: Bladder movement was most pronounced in the anterior and cranial directions. The internal margins required to cover the bladder movements due to filling of the bladder and rectum in 87% of the patients were 2.4 cm in the anterior, 1.1 cm in the posterior, 3.5 cm in the cranial, 0.5 cm in the caudal, and 1.3 cm in the lateral direction. CONCLUSION: The filling volumes of the bladder and rectum have a large impact on bladder movements, especially in the anterior and cranial directions. This should be included in the internal target volume with the introduction of anisotropic margins in conformal radiotherapy for bladder cancer.

  • Impact of changes in bladder and Rectal filling volume on organ motion and dose distribution of the bladder in radiotherapy for urinary bladder cancer.
    International journal of radiation oncology biology physics, 2004
    Co-Authors: Lars Fokdal, Henriette Honore, Morten Hoyer, Peter Meldgaard, Kirsten Fode, Hans Von Der Maase
    Abstract:

    Abstract Purpose To determine the impact of filling volume changes of the urinary bladder and rectum on organ motion and dose distribution of the bladder and rectum during radical radiotherapy for bladder cancer and to calculate the internal margins to secure target coverage. Methods and materials In 15 patients with muscle-invasive bladder cancer, a planning CT scan was performed with a bladder and Rectal Catheter, followed by three immediate CT scans with various filling of the urinary bladder and rectum. After 20 fractions, a fifth CT scan, without catherization, was performed. In each CT study, the bladder and rectum volumes were delineated and matched to the planning CT scan to measure the organ motion and calculate internal margins. These margins were compared with an isotropic standard margin of 2 cm. Dose–volume histograms were analyzed to describe the dose distribution in the bladder and rectum corresponding to various filling volumes. Results Bladder movement was most pronounced in the anterior and cranial directions. The internal margins required to cover the bladder movements due to filling of the bladder and rectum in 87% of the patients were 2.4 cm in the anterior, 1.1 cm in the posterior, 3.5 cm in the cranial, 0.5 cm in the caudal, and 1.3 cm in the lateral direction. Conclusion The filling volumes of the bladder and rectum have a large impact on bladder movements, especially in the anterior and cranial directions. This should be included in the internal target volume with the introduction of anisotropic margins in conformal radiotherapy for bladder cancer.

Masahiro Hiraoka - One of the best experts on this subject based on the ideXlab platform.

  • Impact of double-balloon Rectal Catheter use in external-beam radiotherapy for prostate cancer
    International Journal of Clinical Oncology, 2011
    Co-Authors: Kenji Takayama, Takashi Mizowaki, Yoshiharu Negoro, Yoshiki Norihisa, Masahiro Hiraoka
    Abstract:

    Backgrounds Prostate motion and Rectal sparing are important treatment strategy issues in external-beam radiotherapy for localized prostate cancer. To address these issues, we prospectively investigated the feasibility of using a double-balloon Rectal Catheter. Methods The Rectal Catheter has inner and outer balloons that wedge the anus between them. Computed tomography (CT) examinations with and without the Catheter were conducted in seven patients with localized prostate cancer treated by external-beam radiotherapy. The Rectal wall sparing effect was evaluated using virtual three-dimensional conformal radiotherapy plans in each arm. To evaluate interfractional prostate motion, each patient underwent a series of four CT examinations consisting of a planning CT followed by three additional series of CT with and without a Catheter during the course of radiotherapy. Results Virtual plans demonstrated the reduction of the dose to the rectum by expanding the posterior wall to lie outside the high- to intermediate-dose area when a Catheter was applied. Interfractional prostate motion in the anteroposterior direction was effectively reduced by Catheter usage; the mean ± standard deviation (SD) of the displacement was 1.3 ± 0.9 mm with a Catheter as compared to 2.8 ± 1.8 mm without a Catheter ( P  = 0.014), and the maximum displacement was successfully suppressed to 3 mm with a Catheter compared to 6 mm without a Catheter. Systematic and random components were also reduced with the Catheter. Conclusion These results suggest the feasibility and clinical applicability of the double-balloon Rectal Catheter.

  • Impact of double-balloon Rectal Catheter use in external-beam radiotherapy for prostate cancer
    International journal of clinical oncology, 2010
    Co-Authors: Kenji Takayama, Takashi Mizowaki, Yoshiharu Negoro, Yoshiki Norihisa, Masahiro Hiraoka
    Abstract:

    Prostate motion and Rectal sparing are important treatment strategy issues in external-beam radiotherapy for localized prostate cancer. To address these issues, we prospectively investigated the feasibility of using a double-balloon Rectal Catheter. The Rectal Catheter has inner and outer balloons that wedge the anus between them. Computed tomography (CT) examinations with and without the Catheter were conducted in seven patients with localized prostate cancer treated by external-beam radiotherapy. The Rectal wall sparing effect was evaluated using virtual three-dimensional conformal radiotherapy plans in each arm. To evaluate interfractional prostate motion, each patient underwent a series of four CT examinations consisting of a planning CT followed by three additional series of CT with and without a Catheter during the course of radiotherapy. Virtual plans demonstrated the reduction of the dose to the rectum by expanding the posterior wall to lie outside the high- to intermediate-dose area when a Catheter was applied. Interfractional prostate motion in the anteroposterior direction was effectively reduced by Catheter usage; the mean ± standard deviation (SD) of the displacement was 1.3 ± 0.9 mm with a Catheter as compared to 2.8 ± 1.8 mm without a Catheter (P = 0.014), and the maximum displacement was successfully suppressed to 3 mm with a Catheter compared to 6 mm without a Catheter. Systematic and random components were also reduced with the Catheter. These results suggest the feasibility and clinical applicability of the double-balloon Rectal Catheter.

Hans Von Der Maase - One of the best experts on this subject based on the ideXlab platform.

  • impact of changes in bladder and Rectal filling volume on organ motion and dose distribution of the bladder in radiotherapy for urinary bladder cancer
    International Journal of Radiation Oncology Biology Physics, 2004
    Co-Authors: Lars Fokdal, Henriette Honore, Morten Hoyer, Peter Meldgaard, Kirsten Fode, Hans Von Der Maase
    Abstract:

    PURPOSE: To determine the impact of filling volume changes of the urinary bladder and rectum on organ motion and dose distribution of the bladder and rectum during radical radiotherapy for bladder cancer and to calculate the internal margins to secure target coverage. METHODS AND MATERIALS: In 15 patients with muscle-invasive bladder cancer, a planning CT scan was performed with a bladder and Rectal Catheter, followed by three immediate CT scans with various filling of the urinary bladder and rectum. After 20 fractions, a fifth CT scan, without catherization, was performed. In each CT study, the bladder and rectum volumes were delineated and matched to the planning CT scan to measure the organ motion and calculate internal margins. These margins were compared with an isotropic standard margin of 2 cm. Dose-volume histograms were analyzed to describe the dose distribution in the bladder and rectum corresponding to various filling volumes. RESULTS: Bladder movement was most pronounced in the anterior and cranial directions. The internal margins required to cover the bladder movements due to filling of the bladder and rectum in 87% of the patients were 2.4 cm in the anterior, 1.1 cm in the posterior, 3.5 cm in the cranial, 0.5 cm in the caudal, and 1.3 cm in the lateral direction. CONCLUSION: The filling volumes of the bladder and rectum have a large impact on bladder movements, especially in the anterior and cranial directions. This should be included in the internal target volume with the introduction of anisotropic margins in conformal radiotherapy for bladder cancer.

Hans Von Der Maase - One of the best experts on this subject based on the ideXlab platform.

  • Impact of changes in bladder and Rectal filling volume on organ motion and dose distribution of the bladder in radiotherapy for urinary bladder cancer.
    International journal of radiation oncology biology physics, 2004
    Co-Authors: Lars Fokdal, Henriette Honore, Morten Hoyer, Peter Meldgaard, Kirsten Fode, Hans Von Der Maase
    Abstract:

    Abstract Purpose To determine the impact of filling volume changes of the urinary bladder and rectum on organ motion and dose distribution of the bladder and rectum during radical radiotherapy for bladder cancer and to calculate the internal margins to secure target coverage. Methods and materials In 15 patients with muscle-invasive bladder cancer, a planning CT scan was performed with a bladder and Rectal Catheter, followed by three immediate CT scans with various filling of the urinary bladder and rectum. After 20 fractions, a fifth CT scan, without catherization, was performed. In each CT study, the bladder and rectum volumes were delineated and matched to the planning CT scan to measure the organ motion and calculate internal margins. These margins were compared with an isotropic standard margin of 2 cm. Dose–volume histograms were analyzed to describe the dose distribution in the bladder and rectum corresponding to various filling volumes. Results Bladder movement was most pronounced in the anterior and cranial directions. The internal margins required to cover the bladder movements due to filling of the bladder and rectum in 87% of the patients were 2.4 cm in the anterior, 1.1 cm in the posterior, 3.5 cm in the cranial, 0.5 cm in the caudal, and 1.3 cm in the lateral direction. Conclusion The filling volumes of the bladder and rectum have a large impact on bladder movements, especially in the anterior and cranial directions. This should be included in the internal target volume with the introduction of anisotropic margins in conformal radiotherapy for bladder cancer.

Henriette Honore - One of the best experts on this subject based on the ideXlab platform.

  • impact of changes in bladder and Rectal filling volume on organ motion and dose distribution of the bladder in radiotherapy for urinary bladder cancer
    International Journal of Radiation Oncology Biology Physics, 2004
    Co-Authors: Lars Fokdal, Henriette Honore, Morten Hoyer, Peter Meldgaard, Kirsten Fode, Hans Von Der Maase
    Abstract:

    PURPOSE: To determine the impact of filling volume changes of the urinary bladder and rectum on organ motion and dose distribution of the bladder and rectum during radical radiotherapy for bladder cancer and to calculate the internal margins to secure target coverage. METHODS AND MATERIALS: In 15 patients with muscle-invasive bladder cancer, a planning CT scan was performed with a bladder and Rectal Catheter, followed by three immediate CT scans with various filling of the urinary bladder and rectum. After 20 fractions, a fifth CT scan, without catherization, was performed. In each CT study, the bladder and rectum volumes were delineated and matched to the planning CT scan to measure the organ motion and calculate internal margins. These margins were compared with an isotropic standard margin of 2 cm. Dose-volume histograms were analyzed to describe the dose distribution in the bladder and rectum corresponding to various filling volumes. RESULTS: Bladder movement was most pronounced in the anterior and cranial directions. The internal margins required to cover the bladder movements due to filling of the bladder and rectum in 87% of the patients were 2.4 cm in the anterior, 1.1 cm in the posterior, 3.5 cm in the cranial, 0.5 cm in the caudal, and 1.3 cm in the lateral direction. CONCLUSION: The filling volumes of the bladder and rectum have a large impact on bladder movements, especially in the anterior and cranial directions. This should be included in the internal target volume with the introduction of anisotropic margins in conformal radiotherapy for bladder cancer.

  • Impact of changes in bladder and Rectal filling volume on organ motion and dose distribution of the bladder in radiotherapy for urinary bladder cancer.
    International journal of radiation oncology biology physics, 2004
    Co-Authors: Lars Fokdal, Henriette Honore, Morten Hoyer, Peter Meldgaard, Kirsten Fode, Hans Von Der Maase
    Abstract:

    Abstract Purpose To determine the impact of filling volume changes of the urinary bladder and rectum on organ motion and dose distribution of the bladder and rectum during radical radiotherapy for bladder cancer and to calculate the internal margins to secure target coverage. Methods and materials In 15 patients with muscle-invasive bladder cancer, a planning CT scan was performed with a bladder and Rectal Catheter, followed by three immediate CT scans with various filling of the urinary bladder and rectum. After 20 fractions, a fifth CT scan, without catherization, was performed. In each CT study, the bladder and rectum volumes were delineated and matched to the planning CT scan to measure the organ motion and calculate internal margins. These margins were compared with an isotropic standard margin of 2 cm. Dose–volume histograms were analyzed to describe the dose distribution in the bladder and rectum corresponding to various filling volumes. Results Bladder movement was most pronounced in the anterior and cranial directions. The internal margins required to cover the bladder movements due to filling of the bladder and rectum in 87% of the patients were 2.4 cm in the anterior, 1.1 cm in the posterior, 3.5 cm in the cranial, 0.5 cm in the caudal, and 1.3 cm in the lateral direction. Conclusion The filling volumes of the bladder and rectum have a large impact on bladder movements, especially in the anterior and cranial directions. This should be included in the internal target volume with the introduction of anisotropic margins in conformal radiotherapy for bladder cancer.