The emergence of hyperthermia as a cancer therapy has been an exciting clinical development even though its full potential is still unknown. One of the main problems has been correlating the observed tumor response with the temperature distributions achieved during treatment. Lack of knowledge of complete SAR and temperature distributions within the target tissue volume has led to confusing and conflicting results which will ultimately be used to draw conclusions about hyperthermia as a clinical cancer therapy if the gap in existing knowledge is not closed. The principal hypothesis of the proposed work for addressing this clinical need is that the utilization of treatment measurements in conjunction with computational models as an integrated prognostic tool is of significantly higher clinical value than either measurement or computation used alone. To this end, electrical inverse profiling techniques will be used to estimate both SAR and temperature distributions. In the latter case, differential changes in reconstructed complex permittivity profiles will be correlated to temperature rise through empirical relationships and directly measured temperature data. The primary strengths of this approach are that the underlying physics are well-represented mathematically by the Maxwell equations, changes in the complex permittivities of tissues have established correlations with physiological effects of interest in hyperthermia, and the required measurement techniques and hardware are largely available. The proposed techniques will also incorporate invasive measurements -- a major advantage over completely noninvasive imaging and temperature sensing technologies where electrical inverse profiling has been used. Since clinical hyperthermia treatments already involve invasive measurements and some even utilize invasive heating sources, the demand for internal measurements does not represent a significant departure from the norm. However, when coupled with electrical inverse profiling, internal measurements may provide the information necessary to overcome limitations in noninvasive methodologies, thus offering a technique for accurately estimating complete SAR and temperature distributions during hyperthermia. With knowledge of complete temperature distributions, relationships between therapeutic outcome and variation in tumor temperatures can be determined. Then, the sensitivity of the desired temperature profile to controllable treatment parameters can be systematically studied and treatment protocols which maintain a high likelihood of achieving the desired response can be developed.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA055034-03
Application #
2096266
Study Section
Radiation Study Section (RAD)
Project Start
1992-08-07
Project End
1996-07-31
Budget Start
1994-08-01
Budget End
1995-07-31
Support Year
3
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Dartmouth College
Department
Type
Schools of Engineering
DUNS #
041027822
City
Hanover
State
NH
Country
United States
Zip Code
03755
Meaney, Paul M; Raynolds, Timothy; Potwin, Lincoln et al. (2007) 3-Point support mechanical steering system for high intensity focused ultrasound. Phys Med Biol 52:3045-56
Fang, Qianqian; Meaney, Paul M; Geimer, Shireen D et al. (2004) Microwave image reconstruction from 3-D fields coupled to 2-D parameter estimation. IEEE Trans Med Imaging 23:475-84
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Meaney, Paul M; Paulsen, Keith D; Geimer, Shireen D et al. (2002) Quantification of 3-D field effects during 2-D microwave imaging. IEEE Trans Biomed Eng 49:708-20
Meaney, P M; Paulsen, K D; Pogue, B W et al. (2001) Microwave image reconstruction utilizing log-magnitude and unwrapped phase to improve high-contrast object recovery. IEEE Trans Med Imaging 20:104-16
Paulsen, K D; Meaney, P M (1999) Nonactive antenna compensation for fixed-array microwave imaging--Part I: Model development. IEEE Trans Med Imaging 18:496-507
Meaney, P M; Paulsen, K D; Chang, J T et al. (1999) Nonactive antenna compensation for fixed-array microwave imaging: Part II--Imaging results. IEEE Trans Med Imaging 18:508-18
Chang, J T; Paulsen, K; Meaney, P et al. (1998) Non-invasive thermal assessment of tissue phantoms using an active near field microwave imaging technique. Int J Hyperthermia 14:513-34
Meaney, P M; Paulsen, K D; Hartov, A et al. (1996) Microwave imaging for tissue assessment: initial evaluation in multitarget tissue-equivalent phantoms. IEEE Trans Biomed Eng 43:878-90

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