Diffuse optical tomography of breast cancer during neoadjuvant chemotherapy: A case study with comparison to MRI Regine Choe, a Alper Corlu, Kijoon Lee, Turgut Durduran, Soren D. Konecky, and Monika Grosicka-Koptyra Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19104-6396 Simon R. Arridge Department of Computer Science, University College London, London, WC1E 6BT, United Kingdom Brian J. Czerniecki and Douglas L. Fraker Department of Surgery, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, Pennsylvania 19104 Angela DeMichele Department of Medicine (Heme/Onc), Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, Pennsylvania 19104 Britton Chance Department of Biochemistry and Biophysics, University of Pennsylvania, 3620 Hamilton Walk, Philadelphia, Pennsylvania 19104 Mark A. Rosen Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, Pennsylvania 19104 Arjun G. Yodh Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, Pennsylvania 19104-6396 Received 17 November 2004; revised 13 January 2005; accepted for publication 14 January 2005; published 29 March 2005 We employ diffuse optical tomography DOT to track treatment progress in a female subject presenting with locally advanced invasive carcinoma of the breast during neoadjuvant chemo- therapy. Three-dimensional images of total hemoglobin concentration and scattering identified the tumor. Our measurements reveal tumor shrinkage during the course of chemotherapy, in reasonable agreement with magnetic resonance images of the same subject. A decrease in total hemoglobin concentration contrast between tumor and normal tissue was also observed over time. The results demonstrate the potential of DOT for measuring physiological parameters of breast lesions during chemotherapy. © 2005 American Association of Physicists in Medicine. DOI: 10.1118/1.1869612 Key words: diffuse optical tomography, neoadjuvant chemotherapy, breast cancer, near infrared imaging, breast imaging I. INTRODUCTION Neoadjuvant chemotherapy i.e., preoperative chemotherapy is an important therapeutic approach for women with locally advanced breast cancer LABC. LABC generally refers to lesions larger than 5 cm that may or may not have spread beyond the breast and axillary lymph nodes. If the patient responds to neoadjuvant chemotherapy, the size of the pri- mary tumor decreases, facilitating better control through sur- gery while potentially eradicating micrometastatic disease. 1 Neoadjuvant chemotherapy enables a higher percentage of patients to undergo breast conservation therapy without negatively impacting local recurrence rates or long-term out- come when compared with adjuvant chemotherapy. 2 Addi- tionally, the neoadjuvant setting provides a means to monitor the effectiveness of chemotherapy by observing its effects on the primary tumor in vivo. Information about tumor response during chemotherapy may be useful for treatment optimization. Physical examina- tion, as well as mammographic and ultrasonographic evalu- ations sometimes have limited utility for assessing tumor re- sponse due to chemotherapy-induced fibrosis. 3–5 While magnetic resonance imaging MRI has proved useful for defining the extent of residual disease when compared with pathology, 6,7 and while dynamic contrast-enhanced magnetic resonance imaging DCE-MRI has demonstrated ability to monitor tumor size and vascularity during neoadjuvant che- motherapy using gadolinium contrast agents, 7–9 the high cost and invasiveness of these methods render them impractical for frequent e.g., daily monitoring. Frequent monitoring of vascularity is important. Indeed a reduction of tumor angio- genesis from neoadjuvant chemotherapy in combination with hormone therapy has been confirmed by pathologic 1128 1128 Med. Phys. 32 „4…, April 2005 0094-2405/2005/32„4…/1128/12/$22.50 © 2005 Am. Assoc. Phys. Med.