Mark J Rivard

Tufts University, Бостон, Georgia, United States

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Publications (245)618 Total impact

  • Brachytherapy 06/2015; 14. DOI:10.1016/j.brachy.2015.02.215 · 1.99 Impact Factor
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    ABSTRACT: Purpose: The model S700 Axxent electronic brachytherapy source by Xoft, Inc., was characterized by Rivard et al. in 2006. Since then, the source design was modified to include a new insert at the source tip. Current study objectives were to establish an accurate source model for simulation purposes, dosimetrically characterize the new source and obtain its TG-43 brachytherapy dosimetry parameters, and determine dose differences between the original simulation model and the current model S700 source design.
    Medical Physics 06/2015; 42(6):2764-2776. DOI:10.1118/1.4919280 · 3.01 Impact Factor
  • Prakash Aryal, Janelle A. Molloy, Mark J. Rivard
    Medical Physics 06/2015; 42(6):3085-3088. DOI:10.1118/1.4919619 · 3.01 Impact Factor
  • Medical Physics 06/2015; 42(6):3048-3062. DOI:10.1118/1.4921020 · 3.01 Impact Factor
  • Yun Yang, Mark J. Rivard
    Brachytherapy 05/2015; 14:S68. DOI:10.1016/j.brachy.2015.02.314 · 1.99 Impact Factor
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    ABSTRACT: Noninvasive image-guided breast brachytherapy (NIBB) is an attractive novel approach to deliver accelerated partial breast irradiation (APBI). Calculations of equivalent uniform dose (EUD) were performed to identify the appropriate APBI dose for this technique. APBI plans were developed for 15 patients: five with three-dimensional conformal APBI (3D-CRT), five with multi-lumen intracavitary balloons (m-IBB), and five simulating NIBB treatment. Prescription doses of 34.0 and 38.5 Gy were delivered in 10 fractions for m-IBB and 3D-CRT, respectively. Prescription doses ranging from 34.0 to 38.5 Gy were considered for NIBB. Dose-volume histogram data from all 3D-CRT, m-IBB, and NIBB plans were used to calculate the biologically effective EUD and corresponding EUD to the PTV_eval using the following equation: EUD = EUBED/(n [1 + EUD/α/β]). An α/β value of 4.6 Gy was assumed for breast tumor. EUD for varying NIBB prescription doses were compared with EUD values for the other APBI techniques. Mean PTV_eval volume was largest for 3D-CRT (372.9 cm(3)) and was similar for NIBB and m-IBB (88.7 and 87.2 cm(3), respectively). The EUD value obtained by prescribing 38.5 Gy with 3D-CRT APBI was 38.6 Gy. The EUD value of 34.0 Gy prescribed with m-IBB was 34.4 Gy. EUD values for NIBB ranged from 33.9 to 38.2 Gy for prescription doses ranging from 34.0 to 38.5 Gy. Using EUD calculations to compare APBI techniques and treatment doses, a prescription dose of 36.0 Gy in 10 fractions using NIBB has a comparable biologic equivalent dose to other established brachytherapy techniques. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.
    Brachytherapy 04/2015; 14(4). DOI:10.1016/j.brachy.2015.03.007 · 1.99 Impact Factor
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    ABSTRACT: To assess the radiation dose to the fetus of a pregnant patient undergoing high-dose-rate (HDR) (192)Ir interstitial breast brachytherapy, and to design a new patient setup and lead shielding technique that minimizes the fetal dose. Radiochromic films were placed between the slices of an anthropomorphic phantom modeling the patient. The pregnant woman was seated in a chair with the breast over a table and inside a leaded box. Dose variation as a function of distance from the implant volume as well as dose homogeneity within a representative slice of the fetal position was evaluated without and with shielding. With shielding, the peripheral dose after a complete treatment ranged from 50 cGy at 5 cm from the caudal edge of the breast to <0.1 cGy at 30 cm. The shielding reduces absorbed dose by a factor of two near the breast and more than an order of magnitude beyond 20 cm. The dose is heterogeneous within a given axial plane, with variations from the central region within 50%. Interstitial HDR (192)Ir brachytherapy with breast shielding can be more advantageous than external-beam radiotherapy (EBRT) from a radiation protection point of view, as long as the distance to the uterine fundus is higher than about 10 cm. Furthermore, the weight of the shielding here proposed is notably lower than that needed in EBRT. Shielded breast brachytherapy may benefit pregnant patients needing localized radiotherapy, especially during the early gestational ages when the fetus is more sensitive to ionizing radiation. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
    Physica Medica 02/2015; 31(3). DOI:10.1016/j.ejmp.2015.01.010 · 1.85 Impact Factor
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    ABSTRACT: Noninvasive image-guided breast brachytherapy delivers conformal HDR (192)Ir brachytherapy treatments with the breast compressed, and treated in the cranial-caudal and medial-lateral directions. This technique subjects breast tissue to extreme deformations not observed for other disease sites. Given that, commercially-available software for deformable image registration cannot accurately co-register image sets obtained in these two states, a finite element analysis based on a biomechanical model was developed to deform dose distributions for each compression circumstance for dose summation. The model assumed the breast was under planar stress with values of 30 kPa for Young's modulus and 0.3 for Poisson's ratio. Dose distributions from round and skin-dose optimized applicators in cranial-caudal and medial-lateral compressions were deformed using 0.1 cm planar resolution. Dose distributions, skin doses, and dose-volume histograms were generated. Results were examined as a function of breast thickness, applicator size, target size, and offset distance from the center. Over the range of examined thicknesses, target size increased several millimeters as compression thickness decreased. This trend increased with increasing offset distances. Applicator size minimally affected target coverage, until applicator size was less than the compressed target size. In all cases, with an applicator larger or equal to the compressed target size, > 90% of the target covered by > 90% of the prescription dose. In all cases, dose coverage became less uniform as offset distance increased and average dose increased. This effect was more pronounced for smaller target-applicator combinations. The model exhibited skin dose trends that matched MC-generated benchmarking results within 2% and clinical observations over a similar range of breast thicknesses and target sizes. The model provided quantitative insight on dosimetric treatment variables over a range of clinical circumstances. These findings highlight the need for careful target localization and accurate identification of compression thickness and target offset.
    Journal of Contemporary Brachytherapy 02/2015; 7(1):55-71. DOI:10.5114/jcb.2015.49355
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    ABSTRACT: In the last decade, there have been significant developments into integration of robots and automation tools with brachytherapy delivery systems. These systems aim to improve the current paradigm by executing higher precision and accuracy in seed placement, improving calculation of optimal seed locations, minimizing surgical trauma, and reducing radiation exposure to medical staff. Most of the applications of this technology have been in the implantation of seeds in patients with early-stage prostate cancer. Nevertheless, the techniques apply to any clinical site where interstitial brachytherapy is appropriate. In consideration of the rapid developments in this area, the American Association of Physicists in Medicine (AAPM) commissioned Task Group 192 to review the state-of-the-art in the field of robotic interstitial brachytherapy. This is a joint Task Group with the Groupe Européen de Curiethérapie-European Society for Radiotherapy & Oncology (GEC-ESTRO). All developed and reported robotic brachytherapy systems were reviewed. Commissioning and quality assurance procedures for the safe and consistent use of these systems are also provided. Manual seed placement techniques with a rigid template have an estimated in vivo accuracy of 3-6 mm. In addition to the placement accuracy, factors such as tissue deformation, needle deviation, and edema may result in a delivered dose distribution that differs from the preimplant or intraoperative plan. However, real-time needle tracking and seed identification for dynamic updating of dosimetry may improve the quality of seed implantation. The AAPM and GEC-ESTRO recommend that robotic systems should demonstrate a spatial accuracy of seed placement ≤1.0 mm in a phantom. This recommendation is based on the current performance of existing robotic brachytherapy systems and propagation of uncertainties. During clinical commissioning, tests should be conducted to ensure that this level of accuracy is achieved. These tests should mimic the real operating procedure as closely as possible. Additional recommendations on robotic brachytherapy systems include display of the operational state; capability of manual override; documented policies for independent check and data verification; intuitive interface displaying the implantation plan and visualization of needle positions and seed locations relative to the target anatomy; needle insertion in a sequential order; robot-clinician and robot-patient interactions robustness, reliability, and safety while delivering the correct dose at the correct site for the correct patient; avoidance of excessive force on radioactive sources; delivery confirmation of the required number or position of seeds; incorporation of a collision avoidance system; system cleaning, decontamination, and sterilization procedures. These recommendations are applicable to end users and manufacturers of robotic brachytherapy systems.
    Medical Physics 10/2014; 41(10):101501. DOI:10.1118/1.4895013 · 3.01 Impact Factor
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    ABSTRACT: To investigate the influence of slot design on dose distributions and dose-volume histograms (DVHs) for the model EP917 plaque for episcleral brachytherapy.
    Medical Physics 09/2014; 41(9):092102. DOI:10.1118/1.4892603 · 3.01 Impact Factor
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    ABSTRACT: Purpose To measure the 2D dose distributions with submillimeter resolution for 131Cs (model CS-1 Rev2) and 125I (model 6711) seeds in a Solid Water phantom using radiochromic EBT film for radial distances from 0.06 cm to 5 cm. To determine the TG-43 dosimetry parameters in water by applying Solid Water to liquid water correction factors generated from Monte Carlo simulations. Methods Each film piece was positioned horizontally above and in close contact with a 131Cs or 125I seed oriented horizontally in a machined groove at the center of a Solid Water phantom, one film at a time. A total of 74 and 50 films were exposed to the 131Cs and 125I seeds, respectively. Different film sizes were utilized to gather data in different distance ranges. The exposure time varied according to the seed air-kerma strength and film size in order to deliver doses in the range covered by the film calibration curve. Small films were exposed for shorter times to assess the near field, while larger films were exposed for longer times in order to assess the far field. For calibration, films were exposed to either 40 kV (M40) or 50 kV (M50) x-rays in air at 100.0 cm SSD with doses ranging from 0.2 Gy to 40 Gy. All experimental, calibration and background films were scanned at a 0.02 cm pixel resolution using a CCD camera-based microdensitometer with a green light source. Data acquisition and scanner uniformity correction were achieved with Microd3 software. Data analysis was performed using ImageJ, FV, IDL and Excel software packages. 2D dose distributions were based on the calibration curve established for 50 kV x-rays. The Solid Water to liquid water medium correction was calculated using the MCNP5 Monte Carlo code. Subsequently, the TG-43 dosimetry parameters in liquid water medium were determined. Results Values for the dose-rate constants using EBT film were 1.069±0.036 and 0.923±0.031 cGy U−1 h−1 for 131Cs and 125I seed, respectively. The corresponding values determined using the Monte Carlo method were 1.053±0.014 and 0.924±0.016 cGy U−1 h−1 for 131Cs and 125I seed, respectively. The radial dose functions obtained with EBT film measurements and Monte Carlo simulations were plotted for radial distances up to 5 cm, and agreed within the uncertainty of the two methods. The 2D anisotropy functions obtained with both methods also agreed within their uncertainties. Conclusion EBT film dosimetry in a Solid Water phantom is a viable method for measuring 131Cs (model CS-1 Rev2) and 125I (model 6711) brachytherapy seed dose distributions with submillimeter resolution. With the Solid Water to liquid water correction factors generated from Monte Carlo simulations, the measured TG-43 dosimetry parameters in liquid water for these two seed models were found to be in good agreement with those in the literature.
    Applied Radiation and Isotopes 09/2014; 92:102–114. DOI:10.1016/j.apradiso.2014.06.014 · 1.06 Impact Factor
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    Jesse N Aronowitz, Mark J Rivard
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    ABSTRACT: PurposeTo outline the evolution of computerized brachytherapy treatment planning in the United States through a review of technological developments and clinical practice refinements.Material and methodsA literature review was performed and interviews were conducted with six participants in the development of computerized treatment planning for brachytherapy.ResultsComputerized brachytherapy treatment planning software was initially developed in the Physics Departments of New York's Memorial Hospital (by Nelson, Meurk and Balter), and Houston's M. D. Anderson Hospital (by Stovall and Shalek). These public-domain programs could be used by institutions with adequate computational resources; other clinics had access to them via Memorial's and Anderson's teletype-based computational services. Commercial brachytherapy treatment planning programs designed to run on smaller computers (Prowess, ROCS, MMS), were developed in the late 1980s and early 1990s. These systems brought interactive dosimetry into the clinic and surgical theatre.ConclusionsBrachytherapy treatment planning has evolved from systems of rigid implant rules to individualized pre- and intra-operative treatment plans, and post-operative dosimetric assessments. Brachytherapy dose distributions were initially calculated on public domain programs on large regionally located computers. With the progression of computer miniaturization and increase in processor speeds, proprietary software was commercially developed for microcomputers that offered increased functionality and integration with clinical practice.
    Journal of Contemporary Brachytherapy 06/2014; 6(2):185-90. DOI:10.5114/jcb.2014.43131
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    ABSTRACT: Purpose: To determine the in-air azimuthal anisotropy and in-water dose distribution for the 1 cm length of the CivaString 103Pd brachytherapy source through measurements and Monte Carlo (MC) simulations. American Association of Physicists in Medicine Task Group No. 43 (TG-43) dosimetry parameters were also determined for this source.
    Medical Physics 06/2014; 41(6):389-389. DOI:10.1118/1.4889031 · 3.01 Impact Factor
  • P Aryal, JA Molloy, MJ Rivard
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    ABSTRACT: Purpose: To investigate the effect of slot design of the model EP917 plaque on dose distributions and dose-volume histograms (DVHs).
    Medical Physics 06/2014; 41(6):490-490. DOI:10.1118/1.4889382 · 3.01 Impact Factor
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    ABSTRACT: PURPOSE: To determine the in-air azimuthal anisotropy and in-water dose distribution for the 1 cm length of a new elongated Pd-103 brachytherapy source through both experimental measurements and Monte Carlo (MC) simulations. Measured and MC-calculated dose distributions were used to determine the American Association of Physicists in Medicine Task Group No. 43 (TG-43) dosimetry parameters for this source. METHODS AND MATERIALS: The in-air azimuthal anisotropy of the source was measured with a NaI scintillation detector and was simulated with the MCNP5 radiation transport code. Measured and MC results were normalized to their respective mean values and then compared. The source dose distribution was determined from measurements with LiF:Mg,Ti thermoluminescent dosimeter (TLD) microcubes and MC simulations. TG-43 dosimetry parameters for the source, including the dose-rate constant, Lambda, two-dimensional anisotropy function, F(r, theta), and line-source radial dose function, g(L)(r), were determined from the TLD measurements and MC simulations. RESULTS: NaI scintillation detector measurements and MC simulations of the in-air azimuthal anisotropy of the source showed that >= 95% of the normalized values for each source were within 1.2% of the mean value. TLD measurements and MC simulations of Lambda, F(r, theta), and g(L)(r) agreed to within the associated uncertainties. CONCLUSIONS: This new Pd-103 source exhibits a high level of azimuthal symmetry as indicated by the measured and MC-calculated results for the in-air azimuthal anisotropy. TG-43 dosimetry parameters for the source were determined through TLD measurements and MC simulations.
    Brachytherapy 05/2014; 13(6). DOI:10.1016/j.brachy.2014.04.001 · 1.99 Impact Factor
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    ABSTRACT: In surface and interstitial high-dose-rate brachytherapy with either 60Co, 192Ir, or 169Yb sources, some radiosensitive organs near the surface may be exposed to high absorbed doses. This may be reduced by covering the implants with a lead shield on the body surface, which results in dosimetric perturbations. Monte Carlo simulations in Geant4 were performed for the three radionuclides placed at a single dwell position. Four different shield thicknesses (0, 3, 6, and 10 mm) and three different source depths (0, 5, and 10 mm) in water were considered, with the lead shield placed at the phantom surface. Backscatter dose enhancement and transmission data were obtained for the lead shields. Results were corrected to account for a realistic clinical case with multiple dwell positions. The range of the high backscatter dose enhancement in water is 3 mm for 60Co and 1 mm for both 192Ir and 169Yb. Transmission data for 60Co and 192Ir are smaller than those reported by Papagiannis et al (2008 Med. Phys. 35 4898–4906) for brachytherapy facility shielding; for 169Yb, the difference is negligible. In conclusion, the backscatter overdose produced by the lead shield can be avoided by just adding a few millimetres of bolus. Transmission data provided in this work as a function of lead thickness can be used to estimate healthy organ equivalent dose saving. Use of a lead shield is justified.
    Journal of Radiological Protection 04/2014; 34(2):297. DOI:10.1088/0952-4746/34/2/297 · 1.32 Impact Factor
  • Mark J. Rivard, Yun Yang
    Brachytherapy 03/2014; 13:S52-S53. DOI:10.1016/j.brachy.2014.02.287 · 1.99 Impact Factor
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    ABSTRACT: This white paper was commissioned by the American Society for Radiation Oncology (ASTRO) Board of Directors to evaluate the status of safety and practice guidance for high-dose-rate (HDR) brachytherapy. Given the maturity of HDR brachytherapy technology, this white paper considers, from a safety point of view, the adequacy of general physics and quality assurance guidance, as well as clinical guidance documents available for the most common treatment sites. The rate of medical events in HDR brachytherapy procedures in the United States in 2009 and 2010 was 0.02%, corresponding to 5-sigma performance. The events were not due to lack of guidance documents but failures to follow those recommendations or human failures in the performance of tasks. The white paper summarized by this Executive Summary reviews current guidance documents and offers recommendations regarding their application to delivery of HDR brachytherapy. It also suggests topics where additional research and guidance is needed.
    03/2014; DOI:10.1016/j.prro.2013.12.005
  • Mark J. Rivard, Joshua L. Reed, Larry A. DeWerd
    Brachytherapy 03/2014; 13:S27. DOI:10.1016/j.brachy.2014.02.236 · 1.99 Impact Factor
  • Jessica R. Hiatt, Mark J. Rivard
    Brachytherapy 03/2014; 13:S55-S56. DOI:10.1016/j.brachy.2014.02.292 · 1.99 Impact Factor

Publication Stats

3k Citations
618.00 Total Impact Points

Institutions

  • 2002–2015
    • Tufts University
      • Department of Radiation Oncology
      Бостон, Georgia, United States
  • 2014
    • University of Massachusetts Boston
      Boston, Massachusetts, United States
  • 1999–2013
    • Tufts Medical Center
      • • Department of Radiation Oncology
      • • Department of Neurosurgery
      Boston, Massachusetts, United States
    • Harper University Hospital
      Detroit, Michigan, United States
    • New England Baptist Hospital
      Boston, Massachusetts, United States
  • 2012
    • University Hospital Essen
      Essen, North Rhine-Westphalia, Germany
    • East Carolina University
      North Carolina, United States
    • Hospital Universitari i Politècnic la Fe
      • Radiation Oncology Department
      Valenza, Valencia, Spain
  • 2011
    • University of Wisconsin–Madison
      Madison, Wisconsin, United States
  • 2007–2010
    • Beverly Hospital, Boston MA
      Beverly, Massachusetts, United States
  • 2006
    • Catholic University of Louvain
      Лувен-ла-Нев, Walloon, Belgium
    • Rush University Medical Center
      Chicago, Illinois, United States
    • Yale University
      New Haven, Connecticut, United States
    • Rhode Island Hospital
      Providence, Rhode Island, United States
  • 1996
    • University of Detroit Mercy
      Detroit, Michigan, United States