The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform

Go Watanabe - One of the best experts on this subject based on the ideXlab platform.

  • Transrectal robotic natural orifice translumenal endoscopic surgery (NOTES) applied to intestinal anastomosis in a porcine intestine model.
    Surgical endoscopy, 2013
    Co-Authors: Yoshitaka Demura, Norihiko Ishikawa, Yasumitsu Hirano, Noriyuki Inaki, Aika Matsunoki, Go Watanabe
    Abstract:

    Natural orifice translumenal endoscopic surgery (NOTES) is a minimally invasive operation using devices such as flexible endoscopes and linear or circular staplers. Nevertheless, hand-sewn anastomosis in NOTES remains challenging. This study aimed to investigate the feasibility of transrectal robotic NOTES requiring intracorporeal small intestinal anastomosis and closure of the rectal anterior wall incision in a relevant human model. The authors developed a flexible rectal Proctoscope with a diameter of 43 mm for transrectal robotic NOTES. Small intestinal anastomosis was performed in a porcine intestinal transrectal NOTES model using two robotic arms and a camera inserted through the Proctoscope and a rectal anterior wall incision. The quality of transrectal small intestinal anastomosis using the da Vinci surgical system (transrectal robotic NOTES group) was compared with that of transabdominal anastomosis using the da Vinci surgical system (transabdominal robot-assisted surgery group) and transrectal anastomosis using traditional transanal endoscopic microsurgery (TEM) instruments (TEM NOTES group). The quality of transrectal rectal anterior wall suturing in the transrectal robotic NOTES group was compared with that of the TEM NOTES group and the open surgical instruments group (open group). Robotic intracorporeal suturing was performed successfully in the porcine intestine model. During small intestinal anastomosis, burst pressure in the transrectal robotic NOTES group (67.7 ± 29.3 mmHg) was similar to that in the transabdominal robot-assisted surgery group (73.3 ± 18.2 mmHg) but significantly higher than in the TEM NOTES group (20.3 ± 24.0 mmHg; p 

Yoshitaka Demura - One of the best experts on this subject based on the ideXlab platform.

  • Transrectal robotic natural orifice translumenal endoscopic surgery (NOTES) applied to intestinal anastomosis in a porcine intestine model.
    Surgical endoscopy, 2013
    Co-Authors: Yoshitaka Demura, Norihiko Ishikawa, Yasumitsu Hirano, Noriyuki Inaki, Aika Matsunoki, Go Watanabe
    Abstract:

    Natural orifice translumenal endoscopic surgery (NOTES) is a minimally invasive operation using devices such as flexible endoscopes and linear or circular staplers. Nevertheless, hand-sewn anastomosis in NOTES remains challenging. This study aimed to investigate the feasibility of transrectal robotic NOTES requiring intracorporeal small intestinal anastomosis and closure of the rectal anterior wall incision in a relevant human model. The authors developed a flexible rectal Proctoscope with a diameter of 43 mm for transrectal robotic NOTES. Small intestinal anastomosis was performed in a porcine intestinal transrectal NOTES model using two robotic arms and a camera inserted through the Proctoscope and a rectal anterior wall incision. The quality of transrectal small intestinal anastomosis using the da Vinci surgical system (transrectal robotic NOTES group) was compared with that of transabdominal anastomosis using the da Vinci surgical system (transabdominal robot-assisted surgery group) and transrectal anastomosis using traditional transanal endoscopic microsurgery (TEM) instruments (TEM NOTES group). The quality of transrectal rectal anterior wall suturing in the transrectal robotic NOTES group was compared with that of the TEM NOTES group and the open surgical instruments group (open group). Robotic intracorporeal suturing was performed successfully in the porcine intestine model. During small intestinal anastomosis, burst pressure in the transrectal robotic NOTES group (67.7 ± 29.3 mmHg) was similar to that in the transabdominal robot-assisted surgery group (73.3 ± 18.2 mmHg) but significantly higher than in the TEM NOTES group (20.3 ± 24.0 mmHg; p 

Robert J. Myerson - One of the best experts on this subject based on the ideXlab platform.

  • Design and dosimetric characteristics of a new endocavitary contact radiotherapy system using an electronic brachytherapy source
    Medical physics, 2012
    Co-Authors: Susan Richardson, Robert J. Myerson, Jose Garcia-ramirez, Parag J. Parikh
    Abstract:

    Purpose: To present design aspects and acceptance tests performed for clinical implementation of electronic brachytherapy treatment of early stage rectal adenocarcinoma. A dosimetric comparison is made between the historically used Philips RT-50 unit and the newly developed Axxent{sup Registered-Sign} Model S700 electronic brachytherapy source manufactured by Xoft (iCad, Inc.). Methods: Two Proctoscope cones were manufactured by ElectroSurgical Instruments (ESI). Two custom surface applicators were manufactured by Xoft and were designed to fit and interlock with the Proctoscope cones from ESI. Dose rates, half value layers (HVL), and percentage depth dose (PDD) measurements were made with the Xoft system and compared to historical RT-50 data. A description of the patient treatment approach and exposure rates during the procedure is also provided. Results: The electronic brachytherapy system has a lower surface dose rate than the RT-50. The dose rate to water on the surface from the Xoft system is approximately 2.1 Gy/min while the RT-50 is 10-12 Gy/min. However, treatment times with Xoft are still reasonable. The HVLs and PDDs between the two systems were comparable resulting in similar doses to the target and to regions beyond the target. The exposure rate levels around a patient treatment were acceptable. The standard uncertaintymore » in the dose rate to water on the surface is approximately {+-}5.2%. Conclusions: The Philips RT-50 unit is an out-of-date radiotherapy machine that is no longer manufactured with limited replacement parts. The use of a custom-designed Proctoscope and Xoft surface applicators allows delivery of a well-established treatment with the ease of a modern radiotherapy device. While the dose rate is lower with the use of Xoft, the treatment times are still reasonable. Additionally, personnel may stand farther away from the Xoft radiation source, thus potentially reducing radiation exposure to the operator and other personnel.« less

  • MO-EE-A1-03: A New Technique for Rectal Endocavitary Radiotherapy: Treatment with an Electronic Brachytherapy Source
    Medical Physics, 2010
    Co-Authors: Susan Richardson, Robert J. Myerson, J Garcia Ramirez, Parag J. Parikh
    Abstract:

    Purpose: To present the design aspects and clinical implementation of electronic brachytherapytreatment for early stage rectal adenocarcinoma. A dosimetric comparison between the historically used RT‐50 (Papillon technique) unit and a customized system utilizing the Xoft electronic brachytherapysource is investigated. Materials and Methods: Two Proctoscope cones were manufactured by ElectroSurgical Instruments (ESI). Four custom surface applicators were manufactured by Xoft, Inc. and are designed to fit and interlock with the Proctoscope cones from ESI. Dose rate, Half Value Layer (HVL), Percentage Depth Dose (PDD), and Exposure measurements were made with both the RT‐50 and the Xoft systems. Results: The Xoft system has a lower dose rate than the RT‐50. The average Xoft dose rate is approximately 2 Gy/min while the RT‐50 is 10–11Gy/min. Typical patient treatments are 20–30 Gy, resulting in a 10–15 minute treatment time with the new system compared to 2–3 minutes with the RT‐50. The HVLs and PDDs between the two systems are comparable resulting in similar doses to the target. The exposure rate in the direction of the beam are higher with the Xoft system. Lateral to the beam, the exposure rates are lower, most likely due to higher attenuation in the new stainless steel Proctoscope. Conclusions: The RT‐50 unit is an older radiotherapy machine with limited replacement parts. Additionally the unit is cumbersome to use in an operating room due to its large size. The use of a custom‐designed Proctoscope and commercial Xoft surface applicators allows delivery of a well established treatment with the ease of a modern radiotherapy device. While the treatment time is longer with Xoft, the treating staff may stand farther away from the radiation producing device, thus reducing radiation exposure. The availability of a modern radiotherapy system may result a renewed interest in performing endocavitary radiation therapy.

  • SU‐GG‐T‐549: Dosimetry of An X‐Ray Endocavitary Proctoscope Adapted for Use with the Axxent® Electronic Brachytherapy System
    Medical Physics, 2008
    Co-Authors: Thomas W. Rusch, Eric E. Klein, L Kelley, Robert J. Myerson, Steve Axelrod
    Abstract:

    Purpose: To analyze the dose rate and uniformity at the aperture of an Electro‐Surgical Instrument (ESI). Proctoscope when used with an Axxent® Model S700 X‐ray Source. Method and Materials: The ESI Proctoscope was originally designed for use with a Philips RT‐50 x‐ray contact therapy unit. Because these units are no longer supported, an alternative x‐ray source is being sought which allows for duplication of the Papillon technique for treating anal‐rectal lesions. A source holder was fabricated to position the Axxent model S700 X‐ray Source collinearly on axis within a lead‐lined Proctoscope possessing a 24 mm inner diameter aperture. This mechanism allows the distance from the Proctoscope aperture to the source to be adjusted from 1 to 10 cm and allows a filter to be placed at the distal end of the source to harden the beam and/or flatten the dose distribution. The dose rate was measured at the Proctoscope aperture using a PTW 34013 Soft X‐ray Chamber set into the surface of a Gammex RMI 457 solid water phantom. GAFChromic EBT radiochromic film was used for profile measurements. Results: For operation at 50 kVp and 0.30 mA beam current with a 0.5 mm thick Al filter and source‐to‐aperture distance of 3.4 cm, the dose rate was 1.1 Gy per minute. Profile evaluation indicated a dose uniformity of 5%, 8% and 15% across 80%, 93% and 98% of the aperture diameter, respectively, without use of a flattening filter. Conclusion: Measurements of dose rate and uniformity at the aperture of a 24 mm diameter ESI Proctoscope indicate that the Axxent S700 x‐ray source may be a suitable alternative to the Philips RT‐50 Endocavitary Unit for treatment of anal‐rectal lesions. Conflict of interest: Research sponsored by Xoft, Inc.

  • su gg t 549 dosimetry of an x ray endocavitary Proctoscope adapted for use with the axxent electronic brachytherapy system
    Medical Physics, 2008
    Co-Authors: Thomas W. Rusch, Eric E. Klein, L Kelley, Robert J. Myerson, Steve Axelrod
    Abstract:

    Purpose: To analyze the dose rate and uniformity at the aperture of an Electro‐Surgical Instrument (ESI). Proctoscope when used with an Axxent® Model S700 X‐ray Source. Method and Materials: The ESI Proctoscope was originally designed for use with a Philips RT‐50 x‐ray contact therapy unit. Because these units are no longer supported, an alternative x‐ray source is being sought which allows for duplication of the Papillon technique for treating anal‐rectal lesions. A source holder was fabricated to position the Axxent model S700 X‐ray Source collinearly on axis within a lead‐lined Proctoscope possessing a 24 mm inner diameter aperture. This mechanism allows the distance from the Proctoscope aperture to the source to be adjusted from 1 to 10 cm and allows a filter to be placed at the distal end of the source to harden the beam and/or flatten the dose distribution. The dose rate was measured at the Proctoscope aperture using a PTW 34013 Soft X‐ray Chamber set into the surface of a Gammex RMI 457 solid water phantom. GAFChromic EBT radiochromic film was used for profile measurements. Results: For operation at 50 kVp and 0.30 mA beam current with a 0.5 mm thick Al filter and source‐to‐aperture distance of 3.4 cm, the dose rate was 1.1 Gy per minute. Profile evaluation indicated a dose uniformity of 5%, 8% and 15% across 80%, 93% and 98% of the aperture diameter, respectively, without use of a flattening filter. Conclusion: Measurements of dose rate and uniformity at the aperture of a 24 mm diameter ESI Proctoscope indicate that the Axxent S700 x‐ray source may be a suitable alternative to the Philips RT‐50 Endocavitary Unit for treatment of anal‐rectal lesions. Conflict of interest: Research sponsored by Xoft, Inc.

  • Design and dosimetric characteristics of a high dose rate remotely afterloaded endocavitary applicator system
    International journal of radiation oncology biology physics, 1996
    Co-Authors: Ali S. Meigooni, Eric E. Klein, Robert J. Myerson, Yimin Zhu, Jeffrey F. Williamson, Steven Teague, Edgar Löffler, Gilbert H. Nussbaum, Ira J. Kodner
    Abstract:

    Purpose : An applicator is described for endocavitary treatment of rectal cancers using a high dose rate (HDR) remote afterloading system with a single high-intensity 192 Ir source as an alternative to the 50 kVp x-ray therapy contact unit most frequently used in this application. Methods and Materials : The applicator consists of a tungsten-alloy collimator with a 45° beveled end, placed in a Proctoscope with an elliptical cross-section. The resultant 3 cm diameter circular treatment aperture, located in the beveled face of the Proctoscope, is irradiated by circular array of dwell positions located about 6.5 mm from the applicator surface. This beveled end allows patients with posterior wall tumors to be treated in the dorsal lithotomy position. The dose-rate distributions about the applicator were determined using a combination of thermoluminescent dosimetry (TLD-100 detectors) and radiochromic film dose measurement techniques along with Monte Carlo dosimetry calculations. TLD-100 (3 x 3 x 0.9 mm 3 chips) measurements were used to measure the distribution of dose over the Proctoscope surface as well as the central axis dose-rate distribution. Relative radiochromic film measurements were used to measure off-axis ratios (flatness and penumbra width) within the treatment aperture. These data were combined with Monte Carlo simulation results to obtain the final dose distribution. Results : The tungsten collimator successfully limits the dose to the tissue in contact with the Proctoscope walls to less than 12% of the prescribed dose. These results indicate that the HDR applicator system has slightly more penetrating depth-dose characteristics than the most widely used contact therapy x-ray machine. Flatness characteristics of the two treatment delivery systems are comparable, although the HDR endocavitary applicator has a significantly wider penumbra. Finally, the HDR applicator has a lower surface dose rate (1.5-4 Gy/min of dwell time) compared to 9-10 Gy/min for the x-ray unit. Conclusions : An applicator system has been developed for endocavitary treatment of early stage rectal carcinoma that uses a single-stepping source HDR remote afterloading system as a radiation source. The advantages of the HDR-based system over x-ray therapy contact units currently used in this clinical application are (a) enhanced flexibility in applicator design and (b) widespread availability of single-stepping source HDR remote afterloading systems.

Aika Matsunoki - One of the best experts on this subject based on the ideXlab platform.

  • Transrectal robotic natural orifice translumenal endoscopic surgery (NOTES) applied to intestinal anastomosis in a porcine intestine model.
    Surgical endoscopy, 2013
    Co-Authors: Yoshitaka Demura, Norihiko Ishikawa, Yasumitsu Hirano, Noriyuki Inaki, Aika Matsunoki, Go Watanabe
    Abstract:

    Natural orifice translumenal endoscopic surgery (NOTES) is a minimally invasive operation using devices such as flexible endoscopes and linear or circular staplers. Nevertheless, hand-sewn anastomosis in NOTES remains challenging. This study aimed to investigate the feasibility of transrectal robotic NOTES requiring intracorporeal small intestinal anastomosis and closure of the rectal anterior wall incision in a relevant human model. The authors developed a flexible rectal Proctoscope with a diameter of 43 mm for transrectal robotic NOTES. Small intestinal anastomosis was performed in a porcine intestinal transrectal NOTES model using two robotic arms and a camera inserted through the Proctoscope and a rectal anterior wall incision. The quality of transrectal small intestinal anastomosis using the da Vinci surgical system (transrectal robotic NOTES group) was compared with that of transabdominal anastomosis using the da Vinci surgical system (transabdominal robot-assisted surgery group) and transrectal anastomosis using traditional transanal endoscopic microsurgery (TEM) instruments (TEM NOTES group). The quality of transrectal rectal anterior wall suturing in the transrectal robotic NOTES group was compared with that of the TEM NOTES group and the open surgical instruments group (open group). Robotic intracorporeal suturing was performed successfully in the porcine intestine model. During small intestinal anastomosis, burst pressure in the transrectal robotic NOTES group (67.7 ± 29.3 mmHg) was similar to that in the transabdominal robot-assisted surgery group (73.3 ± 18.2 mmHg) but significantly higher than in the TEM NOTES group (20.3 ± 24.0 mmHg; p 

Noriyuki Inaki - One of the best experts on this subject based on the ideXlab platform.

  • Transrectal robotic natural orifice translumenal endoscopic surgery (NOTES) applied to intestinal anastomosis in a porcine intestine model.
    Surgical endoscopy, 2013
    Co-Authors: Yoshitaka Demura, Norihiko Ishikawa, Yasumitsu Hirano, Noriyuki Inaki, Aika Matsunoki, Go Watanabe
    Abstract:

    Natural orifice translumenal endoscopic surgery (NOTES) is a minimally invasive operation using devices such as flexible endoscopes and linear or circular staplers. Nevertheless, hand-sewn anastomosis in NOTES remains challenging. This study aimed to investigate the feasibility of transrectal robotic NOTES requiring intracorporeal small intestinal anastomosis and closure of the rectal anterior wall incision in a relevant human model. The authors developed a flexible rectal Proctoscope with a diameter of 43 mm for transrectal robotic NOTES. Small intestinal anastomosis was performed in a porcine intestinal transrectal NOTES model using two robotic arms and a camera inserted through the Proctoscope and a rectal anterior wall incision. The quality of transrectal small intestinal anastomosis using the da Vinci surgical system (transrectal robotic NOTES group) was compared with that of transabdominal anastomosis using the da Vinci surgical system (transabdominal robot-assisted surgery group) and transrectal anastomosis using traditional transanal endoscopic microsurgery (TEM) instruments (TEM NOTES group). The quality of transrectal rectal anterior wall suturing in the transrectal robotic NOTES group was compared with that of the TEM NOTES group and the open surgical instruments group (open group). Robotic intracorporeal suturing was performed successfully in the porcine intestine model. During small intestinal anastomosis, burst pressure in the transrectal robotic NOTES group (67.7 ± 29.3 mmHg) was similar to that in the transabdominal robot-assisted surgery group (73.3 ± 18.2 mmHg) but significantly higher than in the TEM NOTES group (20.3 ± 24.0 mmHg; p