Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Thermal applicators
Reexamination Certificate
2000-04-13
2002-10-22
Gibson, Roy D. (Department: 3739)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Thermal applicators
C607S098000, C607S102000
Reexamination Certificate
active
06470217
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to a minimally invasive method for administering focused energy such as adaptive microwave phased array hyperthermia for treating ductal and glandular carcinomas and intraductal hyperplasia as well as benign lesions such as fibroadenomas and cysts in compressed breast tissue. In addition, the method according to the invention may be used to treat healthy tissue containing undetected microscopic pathologically altered cells of high-water content to prevent the occurrence of or the recurrence of cancerous, pre-cancerous or benign breast lesions.
In order to treat primary breast cancer with hyperthermia, it is necessary to heat large volumes of tissue such as a quadrant or more of the breast. It is well known that approximately 90% of all breast cancers originate within the lactiferous ductal tissues (milk ducts) with much of the remaining cancers originating in the glandular tissue lobules (milk sacks) (Harris et al., The New England Journal of Medicine, Vol. 327, pp. 390-398, 1992). Breast carcinomas often involve large regions of the breast for which current conservative treatments have a significant risk of local failure. Schnitt et al., Cancer, Vol. 74 (6) pp. 1746-1751, 1994. With early-stage breast cancer, known as T1 (0-2 cm), T2 (2-5 cm) cancers, the entire breast is at risk and often is treated with breast-conserving surgery combined with full-breast irradiation to destroy any possible microscopic (not visible to the human eye without the aid of a microscope or mammography) cancer cells in the breast tissue (Winchester et al., CA-A Cancer Journal for Clinicians, Vol. 42, No. 3, pp. 134-162, 1992). The successful treatment of invasive ductal carcinomas with an extensive intraductal component (EIC) where the carcinomas have spread throughout the ducts is particularly difficult, since large portions of the breast must be treated. Over 800,000 breast needle biopsies of suspicious lesions are performed annually in the United States with approximately 180,000 cases of cancer detected, the rest being nonmalignant such as fibroadenomas and cysts.
The use of heat to treat breast carcinomas can be effective in a number of ways, and in most cases the heat treatment must be capable of reaching, simultaneously, widely separated areas within the breast. Heating large volumes of the breast can destroy many or all of the microscopic carcinoma cells in the breast, and reduce or prevent the recurrence of cancer—the same approach is used in radiation therapy where the entire breast is irradiated with x-rays to kill all the microscopic cancer cells. Heating the tumor and killing a large percentage or all of the tumor cells prior to lumpectomy may reduce the possibility of inadvertently seeding viable cancer cells during the lumpectomy procedure, thus reducing local recurrences of the breast. Sometimes, the affected breast contains two or more tumor masses distributed within the breast, known as multi-focal cancer, and again the heating field must reach widely separated regions of the breast. Locally advanced breast carcinomas (known as T3) (Smart et al., A Cancer Journal for Clinicians, Vol. 47, pp. 134-139, 1997) can be 5 cm or more in size and are often treated with mastectomy. Pre-operative hyperthermia treatment of locally advanced breast cancer may shrink the tumor sufficiently to allow a surgical lumpectomy procedure to be performed—similar to the way pre-operative chemotherapy is currently used. Pre-operative hyperthermia treatment of locally advanced breast cancer may destroy the tumor completely, eliminating the need of any surgery.
It is well known that microwave energy can preferentially heat high-water content tissues such as breast tumors and cysts, compared to the heating that occurs in low-water content tissue such as fatty breast tissue. Many clinical studies have established that hyperthermia (elevated temperature) induced by electromagnetic energy absorption in the microwave band, significantly enhances the effect of radiation therapy in the treatment of malignant tumors in the human body (Valdagni, et al., International Journal of Radiation Oncology Biology Physics, Vol. 28, pp. 163-169, 1993; Overgaard et al., International Journal of Hyperthermia, Vol. 12, No. 1, pp. 3-20, 1996; Vernon et al., International Journal of Radiation Oncology Biology Physics, Vol. 35, pp. 731-744, 1996; van der Zee et al, Proceedings of the 7
th
International Congress on Hyperthermic Oncology, Rome, Italy, April 9-13, Vol. 11, pp. 215-217, 1996). Radio-resistant cells such as S-phase cells can be killed directly by elevated temperature (Hall, Radiobiology for the Radiologist, 4
th
Edition, JB Lippincott Company, Philadelphia, pp. 262-263, 1994; Perez and Brady, Principles and Practice of Radiation Oncology, Second Edition, JB Lippincott Company, Philadelphia, pp. 396-397, 1994). Hyperthermia treatments with microwave radiating devices are usually administered in several treatment sessions, in which the malignant tumor is heated to about 430° C. for about 60 minutes. It is known that the amount of time to kill tumor cells decreases by a factor of two for each degree increase in temperature above about 43° C. (Sapareto, et al., International Journal of Radiation Oncology Biology Physics, Vol. 10, pp. 787-800, 1984). Thus, a 60-minute treatment at 43° C. can be reduced to only about 15 minutes at 45° C., which is often referred to as an equivalent dose (t
43° C.
equivalent minutes). During treatments with noninvasive microwave applicators, it has proven difficult to heat semi-deep tumors adequately while preventing surrounding superficial healthy tissues from incurring pain or damage due to undesired hot spots. The specific absorption rate (SAR) in tissue is a common parameter used to characterize the heating of tissue. The SAR is proportional to the rise in temperature over a given time intenval times the specific heat of the tissue and for microwave energy the SAR is also proportional to the electric field squared times the tissue electrical conductivity. The units of absolute SAR are watts per kilogram.
Incoherent-array or non-adaptive phased array hyperthermia treatment systems typically are restricted in their use for heating deep tissue, because they tend to overheat intervening superficial tissues, which can cause pain and/or burning. The first published report describing a non-adaptive phased array for deep tissue hyperthermia was a theoretical study (von Hippel, et al., Massachusetts Institute of Technology, Laboratory for Insulation Research, Technical Report 13, AD-769 843, pp. 16-19, 1973). U.S. Pat. No. 3,895,639 to Rodler describes two-channel and four-channel non-adaptive phased away hyperthermia circuits. Recent developments in hyperthermia systems effectively targets the delivery of heat to deep tissue using adaptive phased array technology originally developed for microwave radar systems (Skohuk, Introduction to Radar Systems, Second Edition, McGraw-Hill Book Company, 1980 pp. 332-333; Compton, Adaptive Antennas, Concepts and Performance, Prentice Hall, New Jersey, p. 1 1988; Fenn, IEEE Transactions on Antennas and Propagation, Vol. 38, number 2, pp. 173-185, 1990; U.S. Pat. Nos. 5,251,645; 5,441,532; 5,540,737; 5,810,888).
Bassen et al., Radio Science, Vol. 12, No. 6(5), November-December 1977, pp. 15-25, shows that an electric-field probe can be used to measure the electric-field pattern in tissue, and in particular, shows several examples in which the measured electric-field has a focal peak in the central tissue. This paper also discusses a concept for real-time measurements of the electric-field in living specimens. However, Bassen et al. did not develop the concept of measuring an electric field using real-time with an electric-probe to adaptively focus a phased array.
An adaptive phased array hyperthermia system uses E-field feedback measurements to focus its microwave energy on deep tissue while simultaneously nullifying any energy that might overheat surrounding healthy body tissue. Pre-clinical s
Fenn Alan J.
Mon John
Celsion Corporation
Gibson Roy D.
Venable
Voorhees Catherine M.
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