Charles R Thomas

Oregon Health and Science University, Portland, Oregon, United States

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Publications (189)1132.81 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: Radiation oncology curriculum development is challenging because of limited numbers of trainees at any single institution. The goal of this project is to implement and evaluate a standardized medical student clerkship curriculum following the multi-institutional cooperative group research model. Methods: During the 2013 academic year, a standardized curriculum was implemented at 11 academic medical centers consisting of three 1-hour lectures and a hands-on radiation treatment planning workshop. After the curriculum, students completed anonymous evaluations using Likert-type scales (1 = "not at all" to 5 = "extremely") and free responses. Evaluations asked students to rate their comfort, before and after the curriculum, with radiation oncology as a specialty, knowledge of radiotherapy planning methods, and ability to function as a radiation oncology resident. Nonparametric statistical tests were used in the analysis. Results: Eighty-eight students at 11 academic medical centers completed the curriculum de novo, with a 72.7% (64 of 88) survey response rate. Fifty-seven students (89.1%) reported intent to pursue radiation oncology as their specialty. Median (interquartile range) student ratings of the importance of curricular content were as follows: overview, 4 (4-5); radiation biology/physics, 5 (4-5); practical aspects/emergencies, 5 (4-5); and planning workshop, 4 (4-5). Students reported that the curriculum helped them better understand radiation oncology as a specialty (5 [4-5]), increased specialty decision comfort (4 [3-5]), and would help the transition to radiation oncology residency (4 [4-5]). Students rated their specialty decision comfort significantly higher after completing the curriculum (4 [4-5] versus 5 [5-5]; P < .001). Conclusions: A national standardized curriculum was successfully implemented at 11 academic medical centers, providing proof of principle that curriculum development can follow the multi-institutional cooperative group research model.
    Journal of the American College of Radiology: JACR 09/2015; DOI:10.1016/j.jacr.2015.06.036 · 2.84 Impact Factor
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    ABSTRACT: Low anterior resection or abdominoperineal resection are considered standard treatments for early rectal cancer but may be associated with morbidity in selected patients who are candidates for early distal lesions amenable to local excision (LE). The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. The panel recognizes the importance of accurate staging to identify patients who may be candidates for a LE approach. Patients who may be candidates for LE alone include those with small, low-lying T1 tumors, without adverse pathologic features. Several surgical approaches can be utilized for LE however none include lymph node evaluation. Adjuvant radiation±chemotherapy may be warranted depending on the risk of nodal metastases. Patients with high-risk T1 tumors, T2 tumors not amenable to radical surgery may also benefit from adjuvant treatment; however, patients with positive margins or T3 lesions should be offered abdominoperineal resection or low anterior resection. Neoadjuvant radiation±chemotherapy followed by LE in higher risk patients results in excellent local control, but it is not clear if this approach reduces recurrence rates over surgery alone.
    American journal of clinical oncology 09/2015; 38(5):520-5. DOI:10.1097/COC.0000000000000197 · 3.06 Impact Factor
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    Anuradha Roy · Clifton D Fuller · David I Rosenthal · Charles R Thomas
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    ABSTRACT: Comparison of imaging measurement devices in the absence of a gold-standard comparator remains a vexing problem; especially in scenarios where multiple, non-paired, replicated measurements occur, as in image-guided radiotherapy (IGRT). As the number of commercially available IGRT presents a challenge to determine whether different IGRT methods may be used interchangeably, an unmet need conceptually parsimonious and statistically robust method to evaluate the agreement between two methods with replicated observations. Consequently, we sought to determine, using an previously reported head and neck positional verification dataset, the feasibility and utility of a Comparison of Measurement Methods with the Mixed Effects Procedure Accounting for Replicated Evaluations (COM3PARE), a unified conceptual schema and analytic algorithm based upon Roy's linear mixed effects (LME) model with Kronecker product covariance structure in a doubly multivariate set-up, for IGRT method comparison. An anonymized dataset consisting of 100 paired coordinate (X/ measurements from a sequential series of head and neck cancer patients imaged near-simultaneously with cone beam CT (CBCT) and kilovoltage X-ray (KVX) imaging was used for model implementation. Software-suggested CBCT and KVX shifts for the lateral (X), vertical (Y) and longitudinal (Z) dimensions were evaluated for bias, inter-method (between-subject variation), intra-method (within-subject variation), and overall agreement using with a script implementing COM3PARE with the MIXED procedure of the statistical software package SAS (SAS Institute, Cary, NC, USA). COM3PARE showed statistically significant bias agreement and difference in inter-method between CBCT and KVX was observed in the Z-axis (both p - value<0.01). Intra-method and overall agreement differences were noted as statistically significant for both the X- and Z-axes (all p - value<0.01). Using pre-specified criteria, based on intra-method agreement, CBCT was deemed preferable for X-axis positional verification, with KVX preferred for superoinferior alignment. The COM3PARE methodology was validated as feasible and useful in this pilot head and neck cancer positional verification dataset. COM3PARE represents a flexible and robust standardized analytic methodology for IGRT comparison. The implemented SAS script is included to encourage other groups to implement COM3PARE in other anatomic sites or IGRT platforms.
    BMC Medical Imaging 08/2015; 15(1):35. DOI:10.1186/s12880-015-0074-z · 1.31 Impact Factor
  • JAMA Internal Medicine 08/2015; DOI:10.1001/jamainternmed.2015.4324 · 13.12 Impact Factor
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    ABSTRACT: For resectable gastric cancer, perioperative chemotherapy or adjuvant chemoradiation with chemotherapy are standards of care. The decision making for adjuvant therapeutic management can depend on the stage of the cancer, lymph node positivity, and extent of surgical resection. After gastric cancer resection, postoperative chemotherapy combined with chemoradiation should be incorporated in cases of D0 lymph node dissection, positive regional lymph nodes, poor clinical response to induction chemotherapy, or positive margins. In the setting of a D2 lymph node dissection, especially those with negative regional lymph nodes, adjuvant chemotherapy alone could be considered. The American College of Radiology (ACR) Appropriateness Criteria® are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review includes an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.
    Oncology (Williston Park, N.Y.) 08/2015; 29(8). · 2.32 Impact Factor
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    ABSTRACT: The role of adjuvant radiation for gallbladder carcinoma (GBC) is uncertain. We combine the experience of six National Cancer Institute-designated cancer centers to explore the impact of adjuvant radiation following oncologic resection of GBC. Patients who underwent extended surgery for GBC at Johns Hopkins, Mayo Clinic, Duke University, Oregon Health & Science University, University of Michigan, and University of Texas MD Anderson between 1985 and 2008 were reviewed. Patients with metastatic disease at surgery, gross residual disease, or missing pathologic information were excluded. Of the 112 patients identified, 61 % received adjuvant radiation, 93 % of whom received concurrent chemotherapy. Median follow-up of surviving patients was 47.3 (range 2.2-167.7) months. Patients who received adjuvant radiation had a higher rate of advanced T-stage (57 vs. 16 %, p < 0.01), lymph node involvement (63 vs. 18 %, p < 0.01), and positive microscopic margins (37 vs. 9 %, p < 0.01) compared with patients managed with surgery alone, but overall survival (OS) was comparable between the two cohorts (5-year OS: 49.7 vs. 52.5 %, p = 0.20). Lymph node involvement had the strongest association with poor OS (p < 0.01). Adjuvant radiation was associated with decreased isolated local failure (hazard ratio 0.17, 95 % confidence interval 0.05-0.63, p = 0.01). However, 71 % of recurrences included distant failure. Following oncologic resection for GBC, adjuvant radiation may offer improved local control compared with observation. The benefit of adjuvant radiation beyond chemotherapy alone should therefore be explored. Certainly, the high rate of distant failure highlights the need for more effective systemic therapy.
    Annals of Surgical Oncology 07/2015; DOI:10.1245/s10434-015-4685-y · 3.93 Impact Factor
  • International journal of radiation oncology, biology, physics 07/2015; 92(3):536-539. DOI:10.1016/j.ijrobp.2015.02.040 · 4.26 Impact Factor
  • International journal of radiation oncology, biology, physics 06/2015; 92(2):211-3. DOI:10.1016/j.ijrobp.2015.01.038 · 4.26 Impact Factor
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    ABSTRACT: The role of postoperative therapy in extrahepatic cholangiocarcinoma (EHCC) or gallbladder carcinoma (GBCA) is unknown. S0809 was designed to estimate 2-year survival (overall and after R0 or R1 resection), pattern of relapse, and toxicity in patients treated with this adjuvant regimen. Eligibility criteria included diagnosis of EHCC or GBCA after radical resection, stage pT2-4 or N+ or positive resection margins, M0, and performance status 0 to 1. Patients received four cycles of gemcitabine (1,000 mg/m(2) intravenously on days 1 and 8) and capecitabine (1,500 mg/m(2) per day on days 1 to 14) every 21 days followed by concurrent capecitabine (1,330 mg/m(2) per day) and radiotherapy (45 Gy to regional lymphatics; 54 to 59.4 Gy to tumor bed). With 80 evaluable patients, results would be promising if 2-year survival 95% CI were > 45% and R0 and R1 survival estimates were ≥ 65% and 45%, respectively. A total of 79 eligible patients (R0, n = 54; R1, n = 25; EHCC, 68%; GBCA, 32%) were treated (86% completed). For all patients, 2-year survival was 65% (95% CI, 53% to 74%); it was 67% and 60% in R0 and R1 patients, respectively. Median overall survival was 35 months (R0, 34 months; R1, 35 months). Local, distant, and combined relapse occurred in 14, 24, and nine patients. Grade 3 and 4 adverse effects were observed in 52% and 11% of patients, respectively. The most common grade 3 to 4 adverse effects were neutropenia (44%), hand-foot syndrome (11%), diarrhea (8%), lymphopenia (8%), and leukopenia (6%). There was one death resulting from GI hemorrhage. This combination was well tolerated, has promising efficacy, and provides clinicians with a well-supported regimen. Our trial establishes the feasibility of conducting national adjuvant trials in EHCC and GBCA and provides baseline data for planning future phase III trials. © 2015 by American Society of Clinical Oncology.
    Journal of Clinical Oncology 05/2015; 33(24). DOI:10.1200/JCO.2014.60.2219 · 18.43 Impact Factor
  • Emma B Holliday · Charles R Thomas · Aaron S Kusano
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    ABSTRACT: The aim of this study was to examine the experiences of radiation oncology applicants and to evaluate the prevalence of behaviors that may be in conflict with established ethical standards. An anonymous survey was sent to all 2013 applicants to a single domestic radiation oncology residency program through the National Resident Matching Program (NRMP). Questions included demographics, survey of observed behaviors, and opinions regarding the interview and matching process. Descriptive statistics were presented. Characteristics and experiences of respondents who matched were compared with those who did not match. Questionnaires were returned by 87 of 171 applicants for a 51% response rate. Eighty-two questionnaires were complete and included for analysis. Seventy-eight respondents (95.1%) reported being asked at least 1 question in conflict with the NRMP code of conduct. When asked where else they were interviewing, 64% stated that this query made them uncomfortable. Forty-five respondents (54.9%) reported unsolicited post-interview contact by programs, and 31 (37.8%) felt pressured to give assurances. Fifteen respondents (18.3%) reported being told their rank position or that they were "ranked to match" prior to Match day, with 27% of those individuals indicating this information influenced how they ranked programs. Half of respondents felt applicants often made dishonest or misleading assurances, one-third reported that they believed their desired match outcome could be improved by deliberately misleading programs, and more than two-thirds felt their rank position could be improved by having faculty from their home institutions directly contact programs on their behalf. Radiation oncology applicants report a high prevalence of behaviors in conflict with written NRMP policies. Post-interview communication should be discouraged in order to enhance fairness and support the professional development of future radiation oncologists. Copyright © 2015 Elsevier Inc. All rights reserved.
    International journal of radiation oncology, biology, physics 04/2015; 92(3). DOI:10.1016/j.ijrobp.2015.02.032 · 4.26 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate the effects of neoadjuvant therapy on lymph node harvest (LNH), lymph node ratio (LNR), and overall survival rates after esophagectomy. A retrospective analysis of 111 patients who underwent esophagectomy for esophageal adenocarcinoma from 2001 to 2010 was performed. Patients were divided into two groups: neoadjuvant chemoradiotherapy prior to surgery (NEOSURG) versus surgery alone (SURG). There were 83 patients (75 %) in the NEOSURG group and 28 (25 %) in the SURG group with a mean age of 66 and 67 years, respectively. The median LNH in the NEOSURG group and SURG group was 16.0 and 15.5, respectively (p = 0.57). Within the NEOSURG group, the median LNH was 16 for complete responders, 14 for partial responders, 16 for nonresponders, and 18 in those who were pathologically upstaged (p = 0.434). The median LNR was 0, 0, 0.1, and 0.2, respectively (p < 0.001). Complete response after neoadjuvant therapy demonstrated a trend toward improved survival (p = 0.056). The LNH was not significantly influenced by neoadjuvant treatment or pathologic response. The LNR was inversely related to pathologic response after neoadjuvant therapy. Complete pathologic response to neoadjuvant therapy trends to improve survival rates.
    Journal of Gastrointestinal Surgery 04/2015; 19(7). DOI:10.1007/s11605-015-2821-4 · 2.80 Impact Factor
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    ABSTRACT: In this study we examined the effects of non-myeloablative total body irradiation (TBI) in combination with immunosuppressive chemotherapy on immune homeostasis in rhesus macaques. Our results show administration of cyclosporine A or tacrolimus without radiotherapy did not result in lymphopenia. The addition of TBI to the regimen resulted in lymphopenia as well as alterations in the memory/naïve ratio following reconstitution of lymphocyte populations. Dendritic cell (DC) numbers in whole blood were largely unaffected while the monocyte population was altered by immunosuppressive treatment. Irradiation also resulted in increased levels of circulating cytokines and chemokines that correlated with T cell proliferative bursts and with the shift toward memory T cells. We also report that Anti-thymocyte globulin (ATG) treatment and CD3 immunotoxin administration resulted in a selective and rapid depletion of naïve CD4 and CD8 T cells and increased frequency of memory T cells. We also examined the impact of these treatments on reactivation of latent simian varicella virus (SVV) infection as a model of varicella zoster virus (VZV) infection of humans. None of the treatments resulted in overt SVV reactivation; however, select animals had transient increases in SVV-specific T cell responses following immunosuppression suggestive of subclinical reactivation. Overall, we provide detailed observations into immune modulation by TBI and chemotherapeutic agents in rhesus macaques, an important research model of human disease. This article is protected by copyright. All rights reserved. © 2015 British Society for Immunology.
    Clinical & Experimental Immunology 04/2015; 181(3). DOI:10.1111/cei.12646 · 3.04 Impact Factor
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    ABSTRACT: Medical training spans nearly a decade, during which many physicians traditionally begin families. Although childrearing responsibilities are shared by men and women in the modern era, differences in time allocated to child care by sex and its potential impact on residency experience merit discussion. An anonymous, voluntary, 102-item survey was distributed to 540 current radiation oncology residents and 2014 graduates that asked about marital and parental status, pregnancy during residency, publication productivity, career aspirations, and experiences working with pregnant co-residents. Respondents with children were asked about childcare arrangements, and women who were pregnant during residency were asked about radiation safety, maternity leave, and breastfeeding experiences. A total of 190 respondents completed the survey, 107 men (56.3%) and 84 women (43.7%). Ninety-seven respondents (51.1%) were parents, and 84 (44.2%) reported a pregnancy during residency. Respondents with children more often were male (65% vs 47.3%; P=.014), in a higher level of training (79.3% vs 54.8% were PGY4 or higher; P=.001), were older (median age of 32, interquartile range [IQR]:31-35] vs age 30 [IQR: 29-33]; P<.001), had a PhD (33% vs 19.3%, respectively; P=.033), were married (99% vs 43%, respectively; P<.001), and had a partner who did not work (24.7% vs 1.9%, respectively; <.001). There were no differences in the number of manuscripts published or the number of residents who expressed likelihood of pursing an academic career by parental status. Among parents, men more frequently had partners who did not work (38.1% vs 0%, respectively; P<.001) and reported that their partner performed a greater percentage of childcare duties (70% [IQR: 60%-80%] vs 35% [IQR: 20%-50%], respectively; P<.001). Pregnancy and parenthood are common during residency. Female residents are frequently responsible for more childcare duties than males but have similar research productivity and career aspirations. Further investigation is critical to elucidate gender disparities in parenthood and career development. Copyright © 2015 Elsevier Inc. All rights reserved.
    International journal of radiation oncology, biology, physics 04/2015; 92(3). DOI:10.1016/j.ijrobp.2015.02.024 · 4.26 Impact Factor
  • Timur Mitin · John G Hunter · Charles R Thomas
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    ABSTRACT: To the Editor: In their review of esophageal carcinoma, Rustgi and El-Serag (Dec. 25 issue)(1) do not recommend chemoradiotherapy for the treatment of unresectable disease on the basis of low efficacy and high rates of complications. However, we would like to note that the landmark Radiation Therapy Oncology Group (RTOG) 85-01 trial, which used definitive chemoradiotherapy with fluorouracil and cisplatin, was associated with a median survival of 14 months and a 5-year survival of 27%.(2) So it is not surprising to find that all guidelines recommend definitive chemoradiotherapy for patients with nonmetastatic unresectable disease and those not amenable for surgery. . . .
    New England Journal of Medicine 04/2015; 372(15):1470-1473. DOI:10.1056/NEJMc1500692#SA3 · 55.87 Impact Factor
  • Timur Mitin · C Kristian Enestvedt · Charles R Thomas
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    ABSTRACT: Twenty percent of patients with rectal cancer present with synchronous liver metastases at the time of initial diagnosis. These patients can be treated with a curative intent, although the choice and sequence of treatment modalities are not well established and are commonly debated in multi-disciplinary tumor boards. In this article we review clinical evidence for various treatment approaches and attempt to formulate a pathway for clinicians to use in evaluating and managing these patients.
    Journal of gastrointestinal oncology 04/2015; 6(2):201-7. DOI:10.3978/j.issn.2078-6891.2014.086
  • Gastroenterology 04/2015; 148(4):S-151. DOI:10.1016/S0016-5085(15)30512-6 · 16.72 Impact Factor
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    Ravi Shridhar · David Shibata · Emily Chan · Charles R. Thomas
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    ABSTRACT: Answer questions and earn CME/CNEThe management of squamous cell carcinomas of the anal canal has evolved from surgery as first-line treatment to curative chemoradiation, with surgery reserved for salvage. Significant progress has been made in understanding how to most effectively deliver chemotherapy and reduce toxicity through advancements in radiation delivery. The purpose of this article is to review the multimodality approach to the diagnosis and management of anal cancer based on a review of the published data and in light of available guidelines. CA Cancer J Clin 2015. © 2015 American Cancer Society.
    CA A Cancer Journal for Clinicians 01/2015; 65(2). DOI:10.3322/caac.21259 · 115.84 Impact Factor
  • James A. Tanyi · Charles R. Thomas
    Cancer Epidemiology Biomarkers & Prevention 11/2014; 23(11 Supplement):A61-A61. DOI:10.1158/1538-7755.DISP13-A61 · 4.13 Impact Factor
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    ABSTRACT: The management of rectal cancer in patients with metastatic disease at presentation is highly variable. There are no phase III trials addressing therapeutic approaches, and the optimal sequencing of chemotherapy, radiation therapy, and surgery remains unresolved. Although chemoradiation is standard for patients with stage II/III rectal cancer, its role in the metastatic setting is controversial. Omitting chemoradiation may not be appropriate in all stage IV patients, particularly those with symptomatic primary tumors. Moreover, outcomes in this setting are vastly different, as some treatments carry the potential for cure in selected patients, while others are purely palliative. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application, by the panel, of a well-established consensus methodology (Modified Delphi) to rate the appropriateness of imaging and treatment procedures. In instances in which evidence is lacking or not definitive, expert opinion may be used as the basis for recommending imaging or treatment.
    Oncology (Williston Park, N.Y.) 10/2014; 28(10). · 2.32 Impact Factor
  • Archie Bleyer · Charles R. Thomas · Cornelia Baines · Anthony B. Miller
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    ABSTRACT: Exaggerating the current benefit of screening mammography and minimizing its harms are readily accomplished by the application of assumptions based on data one‐quarter to half of a century old, and they are neither reliable for predicting what is happening today nor appropriate for the treatment advances that have happened since. Helvie and colleagues are culpable of this conduct.
    Cancer 09/2014; 121(2). DOI:10.1002/cncr.29021 · 4.89 Impact Factor

Publication Stats

3k Citations
1,132.81 Total Impact Points


  • 2005–2015
    • Oregon Health and Science University
      • Department of Radiation Medicine
      Portland, Oregon, United States
    • University of Texas Health Science Center at Tyler
      Tyler, Texas, United States
  • 2014
    • University of Michigan
      Ann Arbor, Michigan, United States
  • 2013
    • Mayo Clinic - Scottsdale
      Scottsdale, Arizona, United States
  • 2007–2013
    • University of Portland
      Portland, Oregon, United States
    • Indiana University-Purdue University Indianapolis
      • Department of Radiation Oncology
      Indianapolis, Indiana, United States
  • 2012
    • University of Washington Seattle
      • Department of Radiation Oncology
      Seattle, Washington, United States
  • 2011
    • Portland State University
      Portland, Oregon, United States
  • 2002–2011
    • University of Texas Health Science Center at San Antonio
      • • Department of Radiation Oncology
      • • Department of Radiology
      San Antonio, TX, United States
  • 2010
    • University of Pittsburgh
      • Department of Biostatistics
      Pittsburgh, PA, United States
  • 2007–2010
    • Roswell Park Cancer Institute
      • Department of Radiation Medicine
      Buffalo, New York, United States
  • 2009
    • Rush University Medical Center
      • Department of Radiation Oncology
      Chicago, Illinois, United States
    • University of Texas MD Anderson Cancer Center
      Houston, Texas, United States
  • 2002–2007
    • University of Texas at San Antonio
      San Antonio, Texas, United States
  • 2006
    • University of Chicago
      Chicago, Illinois, United States
  • 2003
    • Emory University
      • Department of Radiation Oncology
      Atlanta, GA, United States
  • 1997–2001
    • Medical University of South Carolina
      • • Hollings Cancer Center
      • • Department of Radiation Oncology
      Charleston, South Carolina, United States