Kenneth R. Hogstrom, Ph.D.

Kenneth R. Hogstrom, PhD
Professor and director, medical physics and Health Physics
DR. CHARLES M. SMITH PROFESSOR OF MEDICAL PHYSICS

Ph.D., 1976 - Rice University

Louisiana State University
Department of Physics & Astronomy
437 Nicholson Hall, Tower Dr.
Baton Rouge, LA 70803-4001
(225) 578-0590-Office

Research Interests

Medical and Health Physics - Radiation Physics

My areas of primary research interest are electron beam radiotherapy, TomoTherapy for superficial cancers, image-guided radiotherapy, and Auger electron therapy using monochromatic x-rays. Research is conducted at Mary Bird Perkins Cancer Center (MBPCC) and the LSU CAMD synchrotron. Electron Beam Therapy: My primary focus is electron conformal therapy (ECT) using both segmented field ECT and bolus ECT. Segmented field ECT utilizes multiple abutted fields of differing energy. Dose uniformity at the borders of abutted fields was recently studied using energy-dependent source-to-collimator distances of the lead-alloy inserts (Richert et al 2007), and currently the potential of using an electron multileaf collimator (eMLC) (Hogstrom et al 2006) to feather the borders is being investigated. Another issue under investigation is a forward planning algorithm for segmented field ECT. We also plan to investigate the improved utility of segmented field ECT for decreased energy spacing on radiotherapy linacs and how that compares with bolus ECT. TomoTherapy for Superficial Cancers: TomoTherapy can offer advantages over electron or mixed beam therapy in the treatment of superficial cancers in that it can easily treat longer fields (head to foot) and can eliminate issues of abutment dosimetry. Essential to its use is proper understanding of superficial dose (0-1 cm depth). The MBPCC research group has investigated superficial dose and the accuracy of the TomoTherapy treatment planning dose algorithm (Smith et al 2008 and Cheek et al 2008). Early research showed the potential for using TomoTherapy in lieu of electron for post mastectomy irradiation of the chest wall and regional lymph nodes (Ashenafi et al 2008). Current studies are focusing on issues of TomoTherapy delivery (bolus and Intrafraction motion). Research comparing TomoTherapy with electron and mixed beam treatment plans in the head is currently under investigation. Image Guided Radiotherapy: Image-guided radiotherapy is particularly useful for irradiation of brain and other small tumors of the head. We have developed a measurement technique with 0.3-mm accuracy to assess IGRT using the BrainLab Novalis ExacTrac System in the brain (Vinci et al 2008). Future studies will use this system to study other sites in the head and to study other modalities such as TomoTherapy. Auger Electron Therapy: The utility of using monochromatic x-rays (CAMD synchrotron light source) to initiate Auger electron therapy via iododeoxyuridine (IUdR) in cellular DNA is under investigation. A radiation therapy experimental beam line (FS= 3x3 cm² and E< 40 keV) has been configured and dosimetry methods established (Dugas et al 2008 and Oves et al 2008). Current research is studying the increased biological effect of this therapy relative to conventional photon therapy on CHO cells as a function of energy and % IUdR. Future experiments will involve small animals and study the ability of using a free-electron laser in lieu of the synchrotron.

Current and Selected Publications

• Hogstrom, K.R., Boyd, R.A., Antolak, J.A., Svatos, M.M., Faddegon B.A., and Rosenman, J.G., "Dosimetry of retractable eMLC for fixed-beam electron therapy," Medical Physics 31, 443-462, 2004.

• K. Hogstrom and P. Almond, "Review of electron beam therapy physics," Phys. Med. Biol. 51, R455 (2006).

• J. Richert, K. Hogstrom, R. Fields, K. Matthews, and R. Boyd, "Improvement of field matching in segmented field electron conformal therapy using a variable SCD application," Phys. Med. Biol. 52, 2459 (2007).

• Smith, K.S., Gibbons, J.P., Gerbi B.J., and Hogstrom, K.R., "Measurement of superficial dose from a static tomotherapy beam," Medical Physics 35, 769-774, 2008.

• Vinci, J., Hogstrom, K.R., and Neck, D., "Accuracy of cranial coplanar beam therapy with BrainLab ExacTrac image guidance," Medical Physics 35, 3809-19, 2008.

• Cheek, D., Gibbons J.P., Rosen I.I., and Hogstrom, K.R., "Accuracy of TomoTherapy treatments for superficial target volumes," Medical Physics 35, 3565-73, 2008.

• Dugas, J.P., Oves, S., Sajo, E., Matthews, K.L., Ham, K., Hogstrom, K.R., "Monochromatic beam characterization for Auger electron dosimetry and radiotherapy," European Journal of Radiology (on-line 2008, in press).

• Oves, S., Hogstrom, K.R., Ham, K., Sajo, E., and Dugas, J.P., "Dosimetry intercomparison using a 35-keV x-ray synchrotron beam," European Journal of Radiology (on-line 2008, in press).

• Ashenafi, M., Boyd, R.A., Lee, T.K., Lo, L.K., Gibbons, J.P., and Hogstrom, K.R., "Comparison of post-mastectomy dose plans for TomoTherapy and conventional mixed-beam therapy," (submitted for publication; thesis at http://etd.lsu.edu/docs/available/etd-08302006-123936/).