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157 Manual Calculation of Dwell Times for Double Catheter Endobronchial HDR Brachytherapy
$46
September 13-16
MOSFET calibration factor for the 30 min measurement was 0.134 cGy/hr/reading. The percentage difference between the calculated and measured dose rates varied with the MOSFET detectors positions in the phantom. The detector located at the centre of the phantom had the least percentage difference (4.2%) whereas those at the phantom base and apex showed a larger percentage difference up to 12.2%. Conclusions: Thirty minute measurement time gave rise to measurement uncertainty of 3.9%. The percentage difference between the measured dose rate with MOSFET and calculated dose rate with VBS is between 4.2% and 12.2%. The results suggest that it is feasible to perform 30 min measurement duration for urethral dose measurement post-prostate brachytherapy. 156 Gynaecologic HDR Interstitial Brachytherapy: The Role of Radiation Oncology Nursing in Multi-disciplinary Care T. Murray, L. Derrah, D. D'Souza, J. Yuen, D. Batchelar, J. Kwon, A. Sugimoto, M. Carey, M. Lock London Regional Cancer Program, University of Western Ontario, London, Ontario david, dsouza @lhsc. on. ca
Background: HDR interstitial brachytherapy (lB) for women with gynaecologic malignancies requires collaboration of a health care team that includes physicians (radiation oncology, gynaecologic oncology, anesthesia), nursing, radiation therapy, medical physics and support staff. In 2003, we established a dedicated program at our institution. Purpose: To develop and define the role of nursing in the delivery of HDR IB. Materials and Methods: Input from health care team members established a dedicated nursing role with specialized skills in perioperative nursing care, radiation safety and knowledge in gynaecologic oncology. Nurses would interact with women throughout the treatment process. A qualitative review was to be performed to assess the value of this approach upon implementation. Results: A pre-procedure teaching session is booked prior to the implant with the nurse. Details of the procedure are more suitably addressed than at the initial consultation with the physician. The same nursing staff assists during the procedure, supports the patient through the treatment process, and provides guidance for other nursing roles (recovery room, use of patient controlled anesthesia). Supervision is provided on transferring the patient to the CT couch for planning to ensure stability of the implant. Nursing is involved in the delivery of radiation and removal of the applicator/needles. After discharge, they address issues that arise from the patient and other health care providers. Conclusions: A dedicated nursing resource for HDR IB has been successfully implemented with 44 implants performed since 2003. Continuity of care has resulted in a high level of satisfaction from women undergoing a difficult treatment process. Improvements in efficiency have been realized by the delegation of additional tasks to nursing (e.g. connection of source guide tubes, removal of applicator/needles) with appropriate supervision. 157 Manual Calculation of Dwell Times for Double Catheter Endobronchial HDR Brachytherapy D. Batchelar, C. Lewis, J. Taylor, A.R. Dar London Regional Cancer Program, University of Western Ontario, London, Ontario deidre, ba tchelar@lhsc, on. ca
Background: High dose rate (HDR) endobronchial brachytherapy can be used to palliate symptoms (hemoptysis, shortness of breath, cough, fever, obstructive pneumonia) of recurrent lung cancer in individuals who have already received external beam radiation. Most HDR lung cancer treatments involve a single catheter, allowing dwell Limes to be determined based on Manchester Tables for linear sources. The use of multiple catheters allows better dose distribution as well as
CARO 2 0 0 6
coverage of a larger volume, including coverage of tumour spread to more than one bronchus. Standard tables cannot be used for multiple catheters due to the mutual influence of the catheters. Dwell times for double catheter treatments must, therefore, be determined using treatment planning software. This process can take up to 45 minutes during which time the patient is very uncomfortable and the catheters may move. Objectives: To develop a method for manually calculating dwell times that will reduce the time between catheter implant and treatment delivery. Methods: The distances between pairs of sources are measured on both an AP and lateral film. These straightforward measurements are used to estimate the true separation of the source pairs. Dwell times determined for single catheters are modified based on the separation determined for each pair. Dwell times calculated manually can be used to produce a postplan to guide further treatment. This method was retrospectively applied to 10 implants from patients treated with optimized plans. Results: The standard plan was determined to produce dose distributions that are judged clinically reasonable and safe. The total dwell times determined manually agree with individually optimized calculations to within 5%. Conclusions: This method can be used to produce a treatment plan within five minutes of films being taken, with greatly reduced distress to the patient. This efficiency makes it an attractive alternative to customized computer-based treatment planning.
158 MPD & DVH: Fusing an Old Concept with Modern Technology for Brachytherapy Prescription J. N. Aronowitz I, L. Liu2, S. Pohar2 University of Massachusetts Medical School, Worcester, Massachussetsl ; Upstate Medical School, Syracuse, New York2 laronowitz@, comcast, net
Objectives: Modern imaging and dosimetry technology are invaluable for defining a three-dimensional target when turnout can be visualized; it is far more difficult to identify a target volume after the tumour has been excised, The Paris system does not utilize the flexibility of modern high dose-rate equipment. A prescription point, such as a depth of 10mm, is often used as a target surrogate, but the localization of this point is arbitrary, and small variations in its selection may result in large differences in delivered dose. We sought to devise a more objective method to prescribe tumour bed brachytherapy after excision. Methods: An old concept, matched peripheral dose (MPD) was revived, and melded with dose-volume histograms (DVH) generated by modern dosimetry technology. Results: An objective technique was devised for retrospectively assessing delivered dose, or prospectively prescribing treatment for tumour-bed brachytherapy. 159 Radiation Exposure from Prostate Brachytherapy Without Fluoroscopy J. Aronowitz I, G. Connocka, R. Haq2, M.J. Morin 2 University of Massachusetts Medical School, Worcester, Massachussets 1; Upstate Medical School, Syracuse, New Yorka ~aronowitz@comcast. net
Objectives: To quantify the brachytherapist's exposure to radiation resulting from performing permanent prostate brachytherapy without fluoroscopic guidance. Methods: The exposure rates from individual iodine and palladium seeds, as well as from seed magazines (plastic and shielded) fully loaded with palladium seeds were measured. Dose to the hands and body of an unshielded brachytherapist performing 46 consecutive implants, using a Mick applicator without fluoroscopy, was measured. Results: Dose to the left hand was 90% lower than published doses associated with fluoroscopy-assisted prostate brachytherapy.
September 13-16
MOSFET calibration factor for the 30 min measurement was 0.134 cGy/hr/reading. The percentage difference between the calculated and measured dose rates varied with the MOSFET detectors positions in the phantom. The detector located at the centre of the phantom had the least percentage difference (4.2%) whereas those at the phantom base and apex showed a larger percentage difference up to 12.2%. Conclusions: Thirty minute measurement time gave rise to measurement uncertainty of 3.9%. The percentage difference between the measured dose rate with MOSFET and calculated dose rate with VBS is between 4.2% and 12.2%. The results suggest that it is feasible to perform 30 min measurement duration for urethral dose measurement post-prostate brachytherapy. 156 Gynaecologic HDR Interstitial Brachytherapy: The Role of Radiation Oncology Nursing in Multi-disciplinary Care T. Murray, L. Derrah, D. D'Souza, J. Yuen, D. Batchelar, J. Kwon, A. Sugimoto, M. Carey, M. Lock London Regional Cancer Program, University of Western Ontario, London, Ontario david, dsouza @lhsc. on. ca
Background: HDR interstitial brachytherapy (lB) for women with gynaecologic malignancies requires collaboration of a health care team that includes physicians (radiation oncology, gynaecologic oncology, anesthesia), nursing, radiation therapy, medical physics and support staff. In 2003, we established a dedicated program at our institution. Purpose: To develop and define the role of nursing in the delivery of HDR IB. Materials and Methods: Input from health care team members established a dedicated nursing role with specialized skills in perioperative nursing care, radiation safety and knowledge in gynaecologic oncology. Nurses would interact with women throughout the treatment process. A qualitative review was to be performed to assess the value of this approach upon implementation. Results: A pre-procedure teaching session is booked prior to the implant with the nurse. Details of the procedure are more suitably addressed than at the initial consultation with the physician. The same nursing staff assists during the procedure, supports the patient through the treatment process, and provides guidance for other nursing roles (recovery room, use of patient controlled anesthesia). Supervision is provided on transferring the patient to the CT couch for planning to ensure stability of the implant. Nursing is involved in the delivery of radiation and removal of the applicator/needles. After discharge, they address issues that arise from the patient and other health care providers. Conclusions: A dedicated nursing resource for HDR IB has been successfully implemented with 44 implants performed since 2003. Continuity of care has resulted in a high level of satisfaction from women undergoing a difficult treatment process. Improvements in efficiency have been realized by the delegation of additional tasks to nursing (e.g. connection of source guide tubes, removal of applicator/needles) with appropriate supervision. 157 Manual Calculation of Dwell Times for Double Catheter Endobronchial HDR Brachytherapy D. Batchelar, C. Lewis, J. Taylor, A.R. Dar London Regional Cancer Program, University of Western Ontario, London, Ontario deidre, ba tchelar@lhsc, on. ca
Background: High dose rate (HDR) endobronchial brachytherapy can be used to palliate symptoms (hemoptysis, shortness of breath, cough, fever, obstructive pneumonia) of recurrent lung cancer in individuals who have already received external beam radiation. Most HDR lung cancer treatments involve a single catheter, allowing dwell Limes to be determined based on Manchester Tables for linear sources. The use of multiple catheters allows better dose distribution as well as
CARO 2 0 0 6
coverage of a larger volume, including coverage of tumour spread to more than one bronchus. Standard tables cannot be used for multiple catheters due to the mutual influence of the catheters. Dwell times for double catheter treatments must, therefore, be determined using treatment planning software. This process can take up to 45 minutes during which time the patient is very uncomfortable and the catheters may move. Objectives: To develop a method for manually calculating dwell times that will reduce the time between catheter implant and treatment delivery. Methods: The distances between pairs of sources are measured on both an AP and lateral film. These straightforward measurements are used to estimate the true separation of the source pairs. Dwell times determined for single catheters are modified based on the separation determined for each pair. Dwell times calculated manually can be used to produce a postplan to guide further treatment. This method was retrospectively applied to 10 implants from patients treated with optimized plans. Results: The standard plan was determined to produce dose distributions that are judged clinically reasonable and safe. The total dwell times determined manually agree with individually optimized calculations to within 5%. Conclusions: This method can be used to produce a treatment plan within five minutes of films being taken, with greatly reduced distress to the patient. This efficiency makes it an attractive alternative to customized computer-based treatment planning.
158 MPD & DVH: Fusing an Old Concept with Modern Technology for Brachytherapy Prescription J. N. Aronowitz I, L. Liu2, S. Pohar2 University of Massachusetts Medical School, Worcester, Massachussetsl ; Upstate Medical School, Syracuse, New York2 laronowitz@, comcast, net
Objectives: Modern imaging and dosimetry technology are invaluable for defining a three-dimensional target when turnout can be visualized; it is far more difficult to identify a target volume after the tumour has been excised, The Paris system does not utilize the flexibility of modern high dose-rate equipment. A prescription point, such as a depth of 10mm, is often used as a target surrogate, but the localization of this point is arbitrary, and small variations in its selection may result in large differences in delivered dose. We sought to devise a more objective method to prescribe tumour bed brachytherapy after excision. Methods: An old concept, matched peripheral dose (MPD) was revived, and melded with dose-volume histograms (DVH) generated by modern dosimetry technology. Results: An objective technique was devised for retrospectively assessing delivered dose, or prospectively prescribing treatment for tumour-bed brachytherapy. 159 Radiation Exposure from Prostate Brachytherapy Without Fluoroscopy J. Aronowitz I, G. Connocka, R. Haq2, M.J. Morin 2 University of Massachusetts Medical School, Worcester, Massachussets 1; Upstate Medical School, Syracuse, New Yorka ~aronowitz@comcast. net
Objectives: To quantify the brachytherapist's exposure to radiation resulting from performing permanent prostate brachytherapy without fluoroscopic guidance. Methods: The exposure rates from individual iodine and palladium seeds, as well as from seed magazines (plastic and shielded) fully loaded with palladium seeds were measured. Dose to the hands and body of an unshielded brachytherapist performing 46 consecutive implants, using a Mick applicator without fluoroscopy, was measured. Results: Dose to the left hand was 90% lower than published doses associated with fluoroscopy-assisted prostate brachytherapy.