Abby Besemer, PhD

Assistant Professor

Abby Besemer, PhD

Abby Besemer, PhD (she/her)

twitterlogo.png @AbbyBesemerPhD

Residency in Medical Physics; University of Wisconsin - Madison; 2018 
PhD in Medical Physics; University of Wisconsin - Madison; 2016 
MS in Medical Physics; University of Wisconsin - Madison; 2013
BS in Physics; Indiana University - Bloomington; 2010
BS in Astronomy/Astrophysics; Indiana University - Bloomington; 2010
BS in Mathematics; Indiana University - Bloomington; 2010

American Board of Radiology - Therapeutic Radiological Physics (2019)

Professional Memberships:
American Association of Physicists in Medicine (AAPM)
Society of Director of Academic Medical Physics Programs (SDAMPP)
American Board of Radiology (ABR)
American Brachytherapy Society (ABS)
Medical Physics for World Benefit

Clinical & Research Interests:
Patient-Specific Dosimetry for Radiopharmaceutical Therapy
Stereotactic Radiosurgery
Safety, Quality Assurance, Standardization of Procedures
Motion Management
Image Guided Radiation Therapy
Monte Carlo

Selected Clinical and Research Projects:

HDR Prostate Brachytherapy
Role: PI (resident involvement)
Here at UNMC, we have recently transitioned from LDR to HDR Brachytherapy for the treatment of prostate cancer. This procedure utilizes Oncentra Prostate which is a real-time planning software that can optimize the implant and needle geometry using ultrasound guidance while the patient is in the operating room. This research involved investigating the dosimetric uncertainties of a variety of aspects of the treatment planning workflow, especially the localization of needles. Additionally, we have developed a real time data tracking system that tracks patient plan and dosimetric statistics of each case so that period reports can be generated and our planning techniques can be adapted and improved over time. Residents working on this project are helping to automate this data collection and reporting process. We have also been collecting data on timing and efficiency to identify aspects of the workflow that can be better streamlined. 

Portal Dosimetry
Role: PI (resident involvement)
UNMC transitioned to using Varian Portal Dosimetry for IMRT QA a couple years ago. This study will present a quantitative and qualitative longitudinal initial experience transitioning from ArcCheck to Varian Portal Dosimetry for a large number of plans and a wide variety of treatment sites. This work will involve the quantitative analysis of our portal dosimetry gamma passing rate results compared to those measured by the traditional ArcCheck detector array. Additionally, it will try to determine which plan parameters correlate with the passing rate of the QA measurements and if any of the parameters may lead to failing QA. Lastly, there are no current publications summarizing a "first-year-experience" after commissioning and transitioning to using portal dosimetry with EPIDs. This will be valuable information for other clinics transitioning to portal dosimetry to learn about various tips, tricks, and pitfalls that we experienced when implementing this new technology. Residents have been heavily involved in this research and presented some of their work at the annual AAPM meeting on this topic. 

Role: PI (resident involvement)
One of the things that I am very passionate about is the standardization of policies and procedures. I am currently in charge of managing a departmental wiki page for internal documentation and procedures. The goal is to have a single location to store information that is easily accessible and editable by everyone in the department. Additionally, the beauty of a wiki is that it allows pages to be interlinked and is also searchable. This is a great resource and educational tool for students and residents and they are actively involved in writing new procedures.

Incident Learning
Role: PI 
We are exploring the use of sending out monthly individualized incident leaning reports to staff to better stay on top of incidents and identify areas of improvement in our clinical workflows. The effectiveness and satisfaction with this process is being evaluated through surveys. 

Role: PI & Co-investigator (resident involvement)
The faculty and UNMC are very passionate about medical physics education and there are numerous educational projects underway. Medical physics resident education is the primary focus of our faculty and there are always ongoing projects to improve the curriculum. Several faculty members and residents have received grants for the development of eLearning projects designed to convert existing lectures or other educational material into interactive eLearning modules. We also completely converted our medical physics course for radiation therapy students to a flipped classroom model which leaves class time open for discussions and problem solving. Additionally, we have also started a peer-review program where faculty members evaluate other's lectures on an annual basis. 

Radiopharmaceutical Therapy
Role: Co-investigator
Radiopharmaceutical therapy is an attractive treatment option for a broad spectrum of tumor types because it has the potential to simultaneously eradicate both the primary tumor site as well as the metastatic disease throughout the body. Like external beam radiation therapy, accurate dosimetry calculations are essential for establishing dose-response relationships during radiopharmaceutical clinical trials and important for reducing the risk of normal tissue complications and optimizing tumor response during targeted radionuclide therapy. However, dosimetry calculations and treatment planning in radiopharmaceutical therapy are performed in a very different way than external beam dose calculations. Thus, the goal of my work has been to develop a Monte Carlo internal dosimetry platform and utilize it to provide patient-specific voxelized dose distributions for radiopharmaceutical pre-clinical and clinical trials. This work is in collaboration with Bryan Bednarz’s research group at the University of Wisconsin.



  1. Besemer A, Grudzinski J, Hall L and Bednarz B, 2018 “Pre-treatment 124I-CLR1404 PET accurately predicts 131I-CLR1404 dosimetry in triple negative breast cancer patient” Cancer Biotherapy and Radiopharmaceuticals.
  2. Besemer A, Yang YM, Grudzinski J, Hall L and Bednarz B, 2018 “Development and validation of RAPID: A patient-specific Monte Carlo 3D internal dosimetry platform” Cancer Biotherapy and Radiopharmaceuticals 33(4), 155-165.
  3. Labby ZE, Barraclough BA, Bayliss RA, Besemer A, Dunkerley DAP, Howard SP, 2018 “Radiation treatment planning and delivery strategies for a pregnant brain tumor patient” Journal of Applied Clinical Medical Physics 19(5), 368-374.
  4. Bednarz B., Grudzinski J., Marsh I., Besemer A., Baiu D., Weichert J., & Otto M. 2018 “Murine-specific Internal Dosimetry for Preclinical Investigations of Imaging and Therapeutic Agents” Health physics114(4), 450-45.
  5. Besemer A, Titz B, Grudzinski J, Weichert4 JP, Kuo JS, Robins HI, Hall LT, and Bednarz BP 2017 “Impact of PET and MRI threshold-based tumor volume segmentation on patient-specific targeted radionuclide therapy dosimetry using CLR1404” Med. Biol. 62.15 6008-602.  
  6. Morris ZS, Weichert JP, Saker J, Armstrong EA, Besemer A, Bednarz BP, Kimple RJ, and Harari PM 2015 "Therapeutic combination of radiolabeled CLR1404 with external beam radiation in head and neck cancer model systems" Radiotherapy and Oncology116 (3) 504-9.
  7. Besemer A, Paganetti H, and Bednarz B 2013“The clinical impact of uncertainties in the mean excitation energy of human tissues during proton therapy” Med. Biol. 58 (4) 887-902.
  8. Buchsbaum JC,Besemer A, Simmons J, Hoene T, Simoneaux V, Sandefur A, Wolanski M, Li Z, Cheng CW  2013 “Supine proton beam craniospinal radiotherapy using a novel tabletop adapter” Med Dosim 38 (1) 70–
  9. Bednarz B and Besemer A 2017 Radiation-Induced Second Cancer Risk Estimates from Radionuclide Therapy. In EPJ Web of Conferences (Vol. 153, p. 04020). EDP Sciences.
  10. Wu H, Besemer A, and Lu M 2014 "Dynamic Correlation of Synchronized Internal Tumor and External Skin Respiratory Motion for Image Guided Lung Cancer Radiation Treatment" International Journal of Computers and their Applications 21 (1) 14-23. 

Conference Publications

  1. Wong JWisnoskie SNie W, Lei Y, Besemer A, "Initial Experience with Varian Portal Dosimetry Patient-Specific QA", AAPM Abstract, 2021
  2. Hyun M, Besemer A, Wisnoskie S, Lei Y, Li S, Schott D, Wang S, Zheng D, Koth J, Bartenhagen L, "Development of a Flipped-Classroom Style Medical Physics Course for Radiation Therapist Students" , AAPM Abstract, 2021
  3. Wong J, Lei Y, Wisnoskie S, Granatowicz A, Wang S, Besemer A, Hyun M, Zhou S, Enke C, Fan Q, "Validation of ClearCalc Photon Secondary Check Dose Calculation Algorithm", AAPM Abstract, 202
  4. Besemer A, “Are patient‐specific QA measurements needed for TomoTherapy 3D conformal plans?, NCC AAPM Chapter Meeting, La Crosse, Wisconsin, November 10, 2017.
  5. Adam D, A Besemer A, Marsh I, Kloepping K, Hall L, Grudzinski J, Weichert J, Otto M, “Towards Patient-Specific Treatment Planning of External Beam Radiotherapy Involving Radiosensitizers Using Nuclear Medicine Imaging”, AAPM Annual Meeting, Denver Colorado, July 30–Aug 4, 2017 [John R. Cameron Young Investigator Symposium Finalist].
  6. Marsh I, Grudzinski J, Besemer A, Weichert J, Harari P, Bednarz B, “Towards Integrated Treatment Planning of Combined External Beam Radiotherapy and Targeted “Radionuclide Therapy”, AAPM Annual Meeting, Denver Colorado, July 30–Aug 4, 2017.
  7. Besemer A, Grudzinski J, Titz B, and Bednarz B “Evaluation of dosimetric uncertainties in individualized targeted radionuclide therapy (TRT) treatment planning using pre-clinical data, AAPM Annual Meeting, Anaheim, California, July 12-16, 2015.
  8. Besemer A, Wikre P, Grudzinski J, and Bednarz B “RAPID: Radiopharmaceutical Assessment Platform for Internal Dosimetry, Society of Nuclear Medicine and Molecular Imaging (SNMMI) Meeting – MIRD Dosimetry Symposium, Baltimore, Maryland, June 3-10, 2015.
  9. Besemer A, Titz B, Grudzinski J, Kozak K, Hall L, Weichert J, and Bednarz B “Impact of PET and MRI Threshold-Based Tumor Volume Segmentation on Targeted Radionuclide Therapy Dosimetry using CLR1404, Society for Brain Mapping and Therapeutics (SBT) Meeting, Sydney, Australia, March 17-20, 2014.
  10. Shepard A, Fowler T, Besemer A, Bednarz B “A Highly Focused Small Animal Irradiator for Preclinical Trials of Low Energy Sources” American Nuclear Society (ANS) National Winter Meeting, Washington, DC, November 10-14, 2013.
  11. Besemer A, Wu H, and Lu M “Dynamic Adaptive Correlation over Synchronous Streaming Time Series”, 26th International Conference on Computer Applications in Industry and Engineering (CAINE-2013), Los Angeles, California, September 25 -27, 2013.
  12. Besemer A, Grudzinski J Titz B, P Wickre, Hall L, Weichert J, and Bednarz B “Towards Personalized Dosimetry using Diapeutic Radiopharmaceuticals”, AAPM Annual Meeting, Indianapolis, Indiana, August 4-8, 2013 [John R. Cameron Young Investigator Symposium Finalist].
  13. Besemer A, Grudzinski J Titz B, Hall L, Weichert J, and Bednarz B, “Monte Carlo-based Radiation Dosimetry for Preclinical Trials of Radiohalogenated Pharmaceuticals”, American Nuclear Society (ANS) Annual Meeting, Atlanta, Georgia, June 16-20, 2013.
  14. Besemer A, Paganetti H, Bednarz B, “Clinical impact of uncertainties in the mean excitation energy of human tissues during proton therapy”, AAPM Annual Meeting, Charlotte, North Carolina, August 1-6, 2013.
  15. Bednarz B, Besemer A, and Yang YM, “A Monte Carlo-based small animal dosimetry platform for pre-clinical trials: proof of concept”, AAPM Annual Meeting, Charlotte, North Carolina, August 1-6, 2013.
  16. Besemer A and Wu H, “Static and Dynamic Polynomial Correlations of Internal/External Marker Positions in Radiotherapy”, Ohio River Valley Chapter 2011 Spring Symposium, Cincinnati, Ohio, March 4-5, 2011.
  17. Besemer A, J Smilowitz, M Geurts, “Is Patient-Specific IMRT QA Needed for TomoTherapy 3D Conformal Radiation Therapy (3D-CRT) Treatment Plans?”, AAPM Annual Meeting, Denver Colorado, July 30–Aug 4, 2017.
  18. Jacqmin D, Labby Z, Besemer A, Schaefer K,“Dose Rate Constancy, MU Linearity and Profile Stability of the TrueBeam Radiotherapy System”, AAPM Annual Meeting, Denver Colorado, July 30–Aug 4, 2017.
  19. Jacqmin D, Huang J, Besemer A, Schaefer K, “Characterization of Spatial Drift for the AlignRT 3D Surface Imaging System Under Multiple Warm-Up Scenarios”, AAPM Annual Meeting, Denver Colorado, July 30–Aug 4, 2017.
  20. Besemer A, Hall L, Bednarz B “In-human validation of the use of pre-treatment molecular imaging for the prediction of patient-specific dosimetry in targeted radionuclide therapy (TRT)”, World Molecular Imaging Congress (WMIC), Honolulu, Hawaii Sept 2-5 2015.
  21. Besemer A and Bednarz B, “Validation of a patient-specific Monte Carlo targeted radionuclide therapy dosimetry platform”, AAPM Annual Meeting, Austin, Texas, July 20 -24, 2014.
  22. Besemer A, Titz B, Grudzinski J, Weichert J, Hall L, and Bednarz B, “Optimizing the combination of targeted radionuclide therapy agents using a multi-scale patient-specific Monte Carlo dosimetry platform”, AAPM Annual Meeting, Austin, Texas, July 20 -24, 2014.
  23. Saker J, Armstrong E, Bednarz B, Besemer A, Farhoud M, Weichert J, and Harari P, “Combination external beam and internal radiation via 131I-CLR1404 in the treatment of head and neck squamous cell carcinoma xenografts”, American Association for Cancer Research (AACR) Annual Meeting, Washington, DC, April 6-10, 2013.