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Giampiero Tosi - One of the best experts on this subject based on the ideXlab platform.
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real time in Vivo Dosimetry using micro mosfet detectors during intraoperative electron beam radiation therapy in early stage breast cancer
Radiotherapy and Oncology, 2006Co-Authors: M Ciocca, Valeria Piazzi, Roberta Lazzari, Andrea Vavassori, Alberto Luini, Paolo Veronesi, Viviana Galimberti, Mattia Intra, Andrea Guido, Giampiero TosiAbstract:Purpose: in a previous paper we reported the results of off-line in Vivo measurements using radiochromic films in IOERT. in the present study, a further step was made, aiming at the improvement of the effectiveness of in Vivo Dosimetry, based on a real-time check of the dose. Materials and methods: Entrance dose was determined using micro-MOSFET detectors placed inside a thin, sterile, transparent catheter. The epoxy side of the detector was faced towards the beam to minimize the anisotropy. Each detector was plugged into a bias supply (standard sensitivity) and calibrated at 5 Gy using 6 MeV electrons produced by a conventional linac. Detectors were characterized in terms of linearity, precision and dose per pulse dependence. No energy and temperature dependence was found. The sensitivity change of detectors was about 1% per 20 Gy accumulated dose. Correction factors to convert surface to entrance dose were determined for each combination of energy and applicator. From November 2004 to May 2005, in Vivo Dosimetry was performed on 45 patients affected by early-stage breast cancer, who underwent IOERT to the tumour bed. IOERT was delivered using electrons (4‐10 MeV) at high dose per pulse, produced by either a Novac7 or a Liac mobile linac. Results: The mean ratio between measured and expected dose was 1.006G0.035 (1 SD), in the range 0.92‐1.1. The procedure uncertainty was 3.6%. Micro-MOSFETs appeared suitable for in Vivo Dosimetry in IOERT, although some unfavourable aspects, like the limited lifetime and the anisotropy with no build-up, were found. Prospectively, a realtime action level (G6%) on dose discrepancy was defined. Conclusions: Excellent agreement between measured and expected doses was found. Real-time in Vivo Dosimetry appeared feasible, reliable and more effective than the method previously published. q 2005 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 78 (2006) 213–216.
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in Vivo Dosimetry using radiochromic films during intraoperative electron beam radiation therapy in early stage breast cancer
Radiotherapy and Oncology, 2003Co-Authors: M Ciocca, Roberta Lazzari, Alberto Luini, Paolo Veronesi, Mattia Intra, Roberto Orecchia, C Garibaldi, E Rondi, Giovanna Gatti, Giampiero TosiAbstract:Abstract Background and purpose : To check the dose delivered to patients during intraoperative electron beam radiation therapy (IOERT) for early breast cancer and also to define appropriate action levels. Patients and methods : Between December 2000 and June 2001, 54 patients affected by early-stage breast cancer underwent exclusive IOERT to the tumour bed using a Novac7 mobile linac, after quadrantectomy. Electron beams (5, 7, 9MeV) at high dose per pulse values (0.02–0.09Gy/pulse) were used. The prescribed single dose was 21Gy at the depth of 90% isodose (14–22 mm). in 35 cases, in Vivo Dosimetry was performed. The entrance dose was derived from the surface dose measured with thin and calibrated MD-55-2 radiochromic films, wrapped in sterile envelopes. Films were analysed 24–72 h after the irradiation using a charge-coupled-device imaging system. Field disturbance caused by the film envelope was negligible. Results : The mean deviation between measured and expected doses was 1.8%, with one SD equal to 4.7%. Deviations larger than 7% were found in 23% of cases, never consecutively, not correlated with beam energy or field size and with no evidence of linac daily output variation or serious malfunctioning or human mistake. The estimated overall uncertainty of dose measurement was about 4%. in Vivo Dosimetry appeared both reliable and feasible. Two action levels, for unexplained observed deviations larger than 7 and 10%, were preliminary defined. Conclusions : Satisfactory agreement between measured and expected doses was found. The implementation of in Vivo Dosimetry in IOERT is suggested, particularly for patients enrolled in a clinical trial.
M Ciocca - One of the best experts on this subject based on the ideXlab platform.
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real time in Vivo Dosimetry using micro mosfet detectors during intraoperative electron beam radiation therapy in early stage breast cancer
Radiotherapy and Oncology, 2006Co-Authors: M Ciocca, Valeria Piazzi, Roberta Lazzari, Andrea Vavassori, Alberto Luini, Paolo Veronesi, Viviana Galimberti, Mattia Intra, Andrea Guido, Giampiero TosiAbstract:Purpose: in a previous paper we reported the results of off-line in Vivo measurements using radiochromic films in IOERT. in the present study, a further step was made, aiming at the improvement of the effectiveness of in Vivo Dosimetry, based on a real-time check of the dose. Materials and methods: Entrance dose was determined using micro-MOSFET detectors placed inside a thin, sterile, transparent catheter. The epoxy side of the detector was faced towards the beam to minimize the anisotropy. Each detector was plugged into a bias supply (standard sensitivity) and calibrated at 5 Gy using 6 MeV electrons produced by a conventional linac. Detectors were characterized in terms of linearity, precision and dose per pulse dependence. No energy and temperature dependence was found. The sensitivity change of detectors was about 1% per 20 Gy accumulated dose. Correction factors to convert surface to entrance dose were determined for each combination of energy and applicator. From November 2004 to May 2005, in Vivo Dosimetry was performed on 45 patients affected by early-stage breast cancer, who underwent IOERT to the tumour bed. IOERT was delivered using electrons (4‐10 MeV) at high dose per pulse, produced by either a Novac7 or a Liac mobile linac. Results: The mean ratio between measured and expected dose was 1.006G0.035 (1 SD), in the range 0.92‐1.1. The procedure uncertainty was 3.6%. Micro-MOSFETs appeared suitable for in Vivo Dosimetry in IOERT, although some unfavourable aspects, like the limited lifetime and the anisotropy with no build-up, were found. Prospectively, a realtime action level (G6%) on dose discrepancy was defined. Conclusions: Excellent agreement between measured and expected doses was found. Real-time in Vivo Dosimetry appeared feasible, reliable and more effective than the method previously published. q 2005 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 78 (2006) 213–216.
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in Vivo Dosimetry using radiochromic films during intraoperative electron beam radiation therapy in early stage breast cancer
Radiotherapy and Oncology, 2003Co-Authors: M Ciocca, Roberta Lazzari, Alberto Luini, Paolo Veronesi, Mattia Intra, Roberto Orecchia, C Garibaldi, E Rondi, Giovanna Gatti, Giampiero TosiAbstract:Abstract Background and purpose : To check the dose delivered to patients during intraoperative electron beam radiation therapy (IOERT) for early breast cancer and also to define appropriate action levels. Patients and methods : Between December 2000 and June 2001, 54 patients affected by early-stage breast cancer underwent exclusive IOERT to the tumour bed using a Novac7 mobile linac, after quadrantectomy. Electron beams (5, 7, 9MeV) at high dose per pulse values (0.02–0.09Gy/pulse) were used. The prescribed single dose was 21Gy at the depth of 90% isodose (14–22 mm). in 35 cases, in Vivo Dosimetry was performed. The entrance dose was derived from the surface dose measured with thin and calibrated MD-55-2 radiochromic films, wrapped in sterile envelopes. Films were analysed 24–72 h after the irradiation using a charge-coupled-device imaging system. Field disturbance caused by the film envelope was negligible. Results : The mean deviation between measured and expected doses was 1.8%, with one SD equal to 4.7%. Deviations larger than 7% were found in 23% of cases, never consecutively, not correlated with beam energy or field size and with no evidence of linac daily output variation or serious malfunctioning or human mistake. The estimated overall uncertainty of dose measurement was about 4%. in Vivo Dosimetry appeared both reliable and feasible. Two action levels, for unexplained observed deviations larger than 7 and 10%, were preliminary defined. Conclusions : Satisfactory agreement between measured and expected doses was found. The implementation of in Vivo Dosimetry in IOERT is suggested, particularly for patients enrolled in a clinical trial.
Joanna E. Cygler - One of the best experts on this subject based on the ideXlab platform.
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in Vivo Dosimetry: trends and prospects for brachytherapy
British Journal of Radiology, 2014Co-Authors: Gustavo Kertzscher, Sam Beddar, Kari Tanderup, Anatoly B. Rosenfeld, Joanna E. CyglerAbstract:The error types during brachytherapy (BT) treatments and their occurrence rates are not well known. The limited knowledge is partly attributed to the lack of independent verification systems of the treatment progression in the clinical workflow routine. Within the field of in Vivo Dosimetry (IVD), it is established that real-time IVD can provide efficient error detection and treatment verification. However, it is also recognized that widespread implementations are hampered by the lack of available high-accuracy IVD systems that are straightforward for the clinical staff to use. This article highlights the capabilities of the state-of-the-art IVD technology in the context of error detection and quality assurance (QA) and discusses related prospects of the latest developments within the field. The article emphasizes the main challenges responsible for the limited practice of IVD and provides descriptions on how they can be overcome. Finally, the article suggests a framework for collaborations between BT cli...
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SU‐E‐T‐600: in Vivo Dosimetry for Total Body and Total Marrow Irradiations with Optically Stimulated Luminescence Dosimeters
Medical Physics, 2014Co-Authors: M Niedbala, C Save, Joanna E. CyglerAbstract:Purpose: To evaluate the feasibility of using optically stimulated luminescence dosimeters (OSLDs) for in-Vivo Dosimetry of patients undergoing Total Body and Total Marrow Irradiations (TBI and TMI). Methods: TBI treatments of 12 Gy were delivered in 6 BID fractions with the patient on a moving couch under a static 10 MV beam (Synergy, Elekta). TMI treatments of 18 Gy in 9 BID fractions were planned and delivered using a 6 MV TomoTherapy unit (Accuray). To provide a uniform dose to the entire patient length, the treatment was split into 2 adjacent fields junctioned in the thigh region. Our standard clinical practice involves in Vivo Dosimetry with MOSFETs for each TBI fraction and TLDs for at least one fraction of the TMI treatment for dose verification. in this study we also used OSLDs. individual calibration coefficients were obtained for the OSLDs based on irradiations in a solid water phantom to the dose of 50 cGy from Elekta Synergy 10 MV (TBI) and 6 MV (TMI) beams. Calibration coefficients were calculated based on the OSLDs readings taken 2 hrs post-irradiation. For in Vivo Dosimetry OSLDs were placed alongside MOSFETs for TBI patients and in approximately the same locations as the TLDs for TMI patients. OSLDs were read 2 hours post treatment and compared to the MOSFET and TLD results. Results: OSLD measured doses agreed within 5% with MOSFET and TLD results, with the exception of the junction region in the TMI patient due to very high dose gradient and difficulty of precise and reproducible detector placement. Conclusion: OSLDs are useful for in Vivo Dosimetry of TBI and TMI patients. The quick post-treatment readout is an advantage over TLDs, allowing the results to be obtained between BID fractions, while wireless detectors are advantageous over MOSFETs for treatments involving a moving couch.
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in Vivo Dosimetry in brachytherapy
Medical Physics, 2013Co-Authors: Kari Tanderup, Gustavo Kertzscher, Sam Beddar, Claus E. Andersen, Joanna E. CyglerAbstract:in Vivo Dosimetry (IVD) has been used in brachytherapy (BT) for decades with a number of different detectors and measurement technologies. However, IVD in BT has been subject to certain difficulties and complexities, in particular due to challenges of the high-gradient BT dose distribution and the large range of dose and dose rate. Due to these challenges, the sensitivity and specificity toward error detection has been limited, and IVD has mainly been restricted to detection of gross errors. Given these factors, routine use of IVD is currently limited in many departments. Although the impact of potential errors may be detrimental since treatments are typically administered in large fractions and with high-gradient-dose-distributions, BT is usually delivered without independent verification of the treatment delivery. This Vision 20/20 paper encourages improvements within BT safety by developments of IVD into an effective method of independent treatment verification.
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SU‐E‐T‐250: Results of a Survey to Assess the Current Status of in‐Vivo Dosimetry in Canada
Medical Physics, 2011Co-Authors: Gabriel Oliveira Sawakuchi, Louis Archambault, A. Scullion, Joanna E. CyglerAbstract:Purpose: To assess the current status of in‐Vivo Dosimetry in the Canadian cancer centers. Methods: A survey on the use of in‐Vivo Dosimetry was performed between July and September 2010. The survey was sent to 39 Canadian cancer centers and it was composed of 16 questions including questions on the use of in‐Vivo Dosimetry as well as demographics of the centers. A total of 34 centers completed the survey. Results: The survey showed that the Ontario and Nova Scotia have the largest number staff per clinic (99 and 75, respectively). Alberta and Manitoba have the largest number of medical physicist per clinic (15 and 12, respectively). The majority of the centers (79%) answered that they perform in‐Vivo Dosimetry to some extent. However, none of the centers perform daily or weekly in‐Vivo dose measurements for individual patients, except for total body irradiation and total skin irradiation treatments. Most of the centers (74%) reported that they use a tolerance level of 5% or higher in their in‐Vivo Dosimetry programs. The majority of the centers (85%) answered that in‐Vivo dose measurements are performed by the medical physicists other than physics assistants, dosimetrists and therapists. As pointed out by the centers, the major drawbacks and difficulties involved in the use of in‐Vivo Dosimetry included increased treatment and staff time. Conclusion: We assessed the current status of in‐Vivo Dosimetry in the Canadian cancer clinics. The results of this survey will serve as a documentation of the current status of the practice of in‐Vivo Dosimetry in Canada. Then, in the future such results will serve as a reference to assess further changes, developments and improvements in the field of in‐Vivo Dosimetry in Canada.
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Quality assurance and application of a 4D in Vivo Dosimetry system using a deformable lung phantom
IFMBE Proceedings, 2009Co-Authors: A Cherpak, M. Serban, Jan Seuntjens, Joanna E. CyglerAbstract:A novel 4D in-Vivo Dosimetry detector (RADPOS) in conjunction with a deformable lung phantom has been used as a quality assurance tool for 4D radiotherapy. A treatment plan was created and delivered with the phantom in two breathing states and the RADOS system was used to verify dose and displacement of the tumour and lung volumes. The RADPOS measured the movement within a maximum deviation of 1.5 mm, and the dose within 4.2% of the total dose. The latest quality assurance and characterization tests of the RADPOS 4-D in-Vivo Dosimetry system are also presented in this work.
Roberta Lazzari - One of the best experts on this subject based on the ideXlab platform.
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real time in Vivo Dosimetry using micro mosfet detectors during intraoperative electron beam radiation therapy in early stage breast cancer
Radiotherapy and Oncology, 2006Co-Authors: M Ciocca, Valeria Piazzi, Roberta Lazzari, Andrea Vavassori, Alberto Luini, Paolo Veronesi, Viviana Galimberti, Mattia Intra, Andrea Guido, Giampiero TosiAbstract:Purpose: in a previous paper we reported the results of off-line in Vivo measurements using radiochromic films in IOERT. in the present study, a further step was made, aiming at the improvement of the effectiveness of in Vivo Dosimetry, based on a real-time check of the dose. Materials and methods: Entrance dose was determined using micro-MOSFET detectors placed inside a thin, sterile, transparent catheter. The epoxy side of the detector was faced towards the beam to minimize the anisotropy. Each detector was plugged into a bias supply (standard sensitivity) and calibrated at 5 Gy using 6 MeV electrons produced by a conventional linac. Detectors were characterized in terms of linearity, precision and dose per pulse dependence. No energy and temperature dependence was found. The sensitivity change of detectors was about 1% per 20 Gy accumulated dose. Correction factors to convert surface to entrance dose were determined for each combination of energy and applicator. From November 2004 to May 2005, in Vivo Dosimetry was performed on 45 patients affected by early-stage breast cancer, who underwent IOERT to the tumour bed. IOERT was delivered using electrons (4‐10 MeV) at high dose per pulse, produced by either a Novac7 or a Liac mobile linac. Results: The mean ratio between measured and expected dose was 1.006G0.035 (1 SD), in the range 0.92‐1.1. The procedure uncertainty was 3.6%. Micro-MOSFETs appeared suitable for in Vivo Dosimetry in IOERT, although some unfavourable aspects, like the limited lifetime and the anisotropy with no build-up, were found. Prospectively, a realtime action level (G6%) on dose discrepancy was defined. Conclusions: Excellent agreement between measured and expected doses was found. Real-time in Vivo Dosimetry appeared feasible, reliable and more effective than the method previously published. q 2005 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 78 (2006) 213–216.
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in Vivo Dosimetry using radiochromic films during intraoperative electron beam radiation therapy in early stage breast cancer
Radiotherapy and Oncology, 2003Co-Authors: M Ciocca, Roberta Lazzari, Alberto Luini, Paolo Veronesi, Mattia Intra, Roberto Orecchia, C Garibaldi, E Rondi, Giovanna Gatti, Giampiero TosiAbstract:Abstract Background and purpose : To check the dose delivered to patients during intraoperative electron beam radiation therapy (IOERT) for early breast cancer and also to define appropriate action levels. Patients and methods : Between December 2000 and June 2001, 54 patients affected by early-stage breast cancer underwent exclusive IOERT to the tumour bed using a Novac7 mobile linac, after quadrantectomy. Electron beams (5, 7, 9MeV) at high dose per pulse values (0.02–0.09Gy/pulse) were used. The prescribed single dose was 21Gy at the depth of 90% isodose (14–22 mm). in 35 cases, in Vivo Dosimetry was performed. The entrance dose was derived from the surface dose measured with thin and calibrated MD-55-2 radiochromic films, wrapped in sterile envelopes. Films were analysed 24–72 h after the irradiation using a charge-coupled-device imaging system. Field disturbance caused by the film envelope was negligible. Results : The mean deviation between measured and expected doses was 1.8%, with one SD equal to 4.7%. Deviations larger than 7% were found in 23% of cases, never consecutively, not correlated with beam energy or field size and with no evidence of linac daily output variation or serious malfunctioning or human mistake. The estimated overall uncertainty of dose measurement was about 4%. in Vivo Dosimetry appeared both reliable and feasible. Two action levels, for unexplained observed deviations larger than 7 and 10%, were preliminary defined. Conclusions : Satisfactory agreement between measured and expected doses was found. The implementation of in Vivo Dosimetry in IOERT is suggested, particularly for patients enrolled in a clinical trial.
Alberto Luini - One of the best experts on this subject based on the ideXlab platform.
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real time in Vivo Dosimetry using micro mosfet detectors during intraoperative electron beam radiation therapy in early stage breast cancer
Radiotherapy and Oncology, 2006Co-Authors: M Ciocca, Valeria Piazzi, Roberta Lazzari, Andrea Vavassori, Alberto Luini, Paolo Veronesi, Viviana Galimberti, Mattia Intra, Andrea Guido, Giampiero TosiAbstract:Purpose: in a previous paper we reported the results of off-line in Vivo measurements using radiochromic films in IOERT. in the present study, a further step was made, aiming at the improvement of the effectiveness of in Vivo Dosimetry, based on a real-time check of the dose. Materials and methods: Entrance dose was determined using micro-MOSFET detectors placed inside a thin, sterile, transparent catheter. The epoxy side of the detector was faced towards the beam to minimize the anisotropy. Each detector was plugged into a bias supply (standard sensitivity) and calibrated at 5 Gy using 6 MeV electrons produced by a conventional linac. Detectors were characterized in terms of linearity, precision and dose per pulse dependence. No energy and temperature dependence was found. The sensitivity change of detectors was about 1% per 20 Gy accumulated dose. Correction factors to convert surface to entrance dose were determined for each combination of energy and applicator. From November 2004 to May 2005, in Vivo Dosimetry was performed on 45 patients affected by early-stage breast cancer, who underwent IOERT to the tumour bed. IOERT was delivered using electrons (4‐10 MeV) at high dose per pulse, produced by either a Novac7 or a Liac mobile linac. Results: The mean ratio between measured and expected dose was 1.006G0.035 (1 SD), in the range 0.92‐1.1. The procedure uncertainty was 3.6%. Micro-MOSFETs appeared suitable for in Vivo Dosimetry in IOERT, although some unfavourable aspects, like the limited lifetime and the anisotropy with no build-up, were found. Prospectively, a realtime action level (G6%) on dose discrepancy was defined. Conclusions: Excellent agreement between measured and expected doses was found. Real-time in Vivo Dosimetry appeared feasible, reliable and more effective than the method previously published. q 2005 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 78 (2006) 213–216.
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in Vivo Dosimetry using radiochromic films during intraoperative electron beam radiation therapy in early stage breast cancer
Radiotherapy and Oncology, 2003Co-Authors: M Ciocca, Roberta Lazzari, Alberto Luini, Paolo Veronesi, Mattia Intra, Roberto Orecchia, C Garibaldi, E Rondi, Giovanna Gatti, Giampiero TosiAbstract:Abstract Background and purpose : To check the dose delivered to patients during intraoperative electron beam radiation therapy (IOERT) for early breast cancer and also to define appropriate action levels. Patients and methods : Between December 2000 and June 2001, 54 patients affected by early-stage breast cancer underwent exclusive IOERT to the tumour bed using a Novac7 mobile linac, after quadrantectomy. Electron beams (5, 7, 9MeV) at high dose per pulse values (0.02–0.09Gy/pulse) were used. The prescribed single dose was 21Gy at the depth of 90% isodose (14–22 mm). in 35 cases, in Vivo Dosimetry was performed. The entrance dose was derived from the surface dose measured with thin and calibrated MD-55-2 radiochromic films, wrapped in sterile envelopes. Films were analysed 24–72 h after the irradiation using a charge-coupled-device imaging system. Field disturbance caused by the film envelope was negligible. Results : The mean deviation between measured and expected doses was 1.8%, with one SD equal to 4.7%. Deviations larger than 7% were found in 23% of cases, never consecutively, not correlated with beam energy or field size and with no evidence of linac daily output variation or serious malfunctioning or human mistake. The estimated overall uncertainty of dose measurement was about 4%. in Vivo Dosimetry appeared both reliable and feasible. Two action levels, for unexplained observed deviations larger than 7 and 10%, were preliminary defined. Conclusions : Satisfactory agreement between measured and expected doses was found. The implementation of in Vivo Dosimetry in IOERT is suggested, particularly for patients enrolled in a clinical trial.
