Quantitative Assessment of Tissue Toxicity in Breast Cancer Radiation Therapy Using Ultrasonic Tissue Characterization Imaging

Tian Liu,¹ Shermian A. Woodhouse,¹ Peter B. Schiff, ¹ Sabiha Islam.,¹ Zhengfeng Lu,² Gerald J Kutcher¹

¹Department of Radiation Oncology, Columbia University, New York, NY

²Department of Radioolgy, Columbia University, New York, NY

For women with early stage breast cancer, breast-conservation surgery in combination with radiation therapy is an effective treatment. However, there is currently no objective means of measuring breast tissue injury/toxicity in the clinic. We have developed an ultrasonic tissue characterization technique (UTC) to quantitatively evaluate radiation toxicity (e.g. fibrosis and edema). Our UTC technique utilizes the ultrasonic radio-frequency echo signals and measures the physical properties (e.g. size, shape and stiffness) of tissue microstructures.

UTC studies were performed on two structurally different beef muscle fibers with variable collagen density, water content and muscle fiber thickness (related to fibrosis and edema). Muscle fibers were scanned with a 40-MHz ultrasound transducer. Ultrasonic parameters which include radially-integrated spectral power and angularly-integrated spectral power were computed for each muscle group. UTC demonstrated a significant separation between parameters measured for these two different muscle fibers (T test p < 0.05). We are conducting an IRB approved study to monitor breast radiation toxicity. All patients will receive an ultrasound scan for the treated breast and the contra-lateral breast prior to treatment, at weekly intervals during treatment; and at one month, six months and one-year post radiation treatment. The radiation oncologist will assess toxicity using the RTOG breast toxicity criteria at the time of ultrasound scanning.

UTC technique provides a basis from which to explore the quantitative assessment of radiation toxicity. As radiation treatment techniques advance, e.g. partial breast IMRT, this diagnostic information will become indispensable for monitoring and evaluation of treatment regiments and for better management of acute and late toxicity.