Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
2001-04-26
2003-01-28
Walberg, Teresa (Department: 3742)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C604S022000, C606S027000, C601S002000, C601S003000
Reexamination Certificate
active
06511428
ABSTRACT:
TECHNICAL FIELD
The present invention is related to an ultrasound therapy system for irradiating focused ultrasound used in medical treatments, and more specifically, is directed to such an ultrasound therapy system equipped with an intraluminal catheter functioning as a supplementary role of medical treatments.
BACKGROUND ART
Various therapeutical methods are known in the field so s to execute minimally invasive tissue treatments by irradiating ultrasound from an outside of a body, or in an intraluminal manner. For instance, there is such a therapeutical method for a prostate by employing an ultrasound generator which is arranged inside a rectum.
As an example of ultrasonic therapy applicable to a disease related to a prostate, a prostatomegaly may be cited. A prostatomegaly implies such a disease that since at least a portion of a prostate becomes a hypertrophy, a urethra is bent, so that a patient must conspicuously have an obstruction of a urinary stream, an urgency of voiding, and a frequent urination. As therapeutical methods, the following methods have been proposed, namely, a method for removing a disease portion by a surgical operation, and a method for burning out a disease portion by irradiating a laser thereto. In contrast with these methods, when the ultrasound therapy apparatus disclosed in U.S. Pat. No. 5,676,692 is employed, medical operations can be carried out in a simpler manner, and also an early recovery from the medical operation could be expected. This ultrasound therapy apparatus is arranged by the therapeutical probe, the ultrasonic diagnostic apparatus connected to the therapeutical probe, the power supply used to generate the focused ultrasound, and also the urethral catheter for reflecting the ultrasound. This therapeutical probe contains the focused ultrasound generating source having the two roles, namely, the generation of the continuous wave for therapeutical purposes, and also the generation of the pulse wave used to acquire the ultrasound tomographic image. As the therapeutical method, under such a condition that the catheter is firstly inserted from a urethra to a bladder, the ultrasonic tomographic apparatus probe is inserted into a rectum so as to acquire an ultrasonic tomographic image of a region in the vicinity of the urethra. Thus, a target region for medical treatment is previously determined. Next, the therapeutical probe is inserted into the rectum, and the ultrasonic tomographic image of the region in the vicinity of the prostate is acquired from the ultrasonic pulse signal derived from the therapeutical probe. In this ultrasound therapy apparatus, the ultrasound-generating source for ultrasonic tomographic images may have another function of the therapeutical ultrasound generating source capable of irradiating the continuous wave, it is practically difficult to optimize this ultrasound generating source in order to generate such a pulse wave used to produce the diagnostic tomographic image. That is, it is practically difficult to obtain tomographic images having better image qualities. As a consequence, in this therapy apparatus, while the catheter having the function capable of reflecting the ultrasound is employed, this apparatus is arranged in such a manner that the reflection signals having the strong strengths can be obtained from the catheter. Since the position of the catheter within the tomographic image is confirmed, such a confirmation is made of the position of the target region for treatment within the tomographic image obtained by employing this therapy apparatus. This treatment target region is indicated in such a tomographic image which has been previously acquired by using the ultrasonic tomographic apparatus probe. After the above-described operations have been carried out, the ultrasound for therapeutical purposes is irradiated from the therapeutical probe to the treatment target region. Normally, a time duration required for irradiating ultrasound one time is approximated to several seconds. In the case that a plurality of target regions are medically treated, normally, intervals of approximately 15 seconds are induced. The therapeutical effects may be conceived by the following reason. That is, since the ultrasound is irradiated onto a tissue, this tissue is heated at such a temperature higher than, or equal to the temperature at which this tissue is brought into the thermo-coagulation.
On the other hand, in the case that ultrasound is irradiated onto a living body, it is known that such a cavitation phenomenon may occur other than the heating effect. In this cavitation phenomenon, bubbles called as “cavitation” are produced and will collasp after being grown. Since both the chemical effect and the mechanical effect can be obtained by this cavitation phenomenon, also in the therapeutical operation using the ultrasound, therapeutical effects may be achieved by actively producing the cavitation and by solely utilizing the chemical effect and/or the mechanical effect achieved by this cavitation, or by combining these chemical/mechanical effects with the heating effect by the ultrasound. In such a case that ultrasound is irradiated from an inrectum portion toward a prostate and the like, this ultrasound may constitute a progressive wave condition. However, usually, cavitation can be hardly produced under such a progressive wave condition. To easily produce such a cavitation, the following fact is known. That is, while a substance and the like, which may reflect ultrasound, are employed, the ultrasound is advantageously irradiated under a standing wave condition. In the therapeutical method described in the above-explained U.S. Pat. No. 5,676,692, the reason why the catheter having the feature of reflecting the ultrasound is employed is intended to this cavitation effect. In other words, on the side of the ultrasound generating source for therapeutical purposes from the catheter, the ultrasound directly reached from the ultrasound generating source for therapeutical purposes is overlapped with the reflection wave from the catheter, so that the temperature increase can be effectively achieved. In addition thereto, since the progressive wave produced from the ultrasound generating source for therapeutical purposes and the reflection wave from the catheter may produce the standing wave, the cavitation effect can be promoted.
As previously disclosed in U.S. Pat. No. 5,523,058, with respect to this cavitation technique, the following fact is known. That is, since one frequency component is superimposed on a doubled frequency component, such ultrasound having a waveform suitable for this cavitation may be obtained even under the progressive wave condition.
DISCLOSURE OF INVENTION
Roughly speaking, there are three problems in the conventional therapeutical methods for the prostatomegaly with employment of the focused ultrasound.
As a first problem, the conditions of the prostate cannot be confirmed during medical treatments. In the case that the prostate is brought into the prostatomegaly state, even if the prostatomegaly portion is cut out, since this cut prostate will normally recur after a predetermined time period has passed, such a medical treatment must be carried out many times. To extend a treatment interval, it is desirable to remove such a prostatomegaly portion having a permittably wide area within a single medical treatment. On the other hand, in order to improve a quality of life after medical operation, it is desirable to avoid such irradiation of ultrasound onto a sphincter:muscle and an outlet of seminal vesicle. In the conventional therapy apparatus, since the energy of the focused ultrasound for therapeutic purposes is considerably larger than the energy of the ultrasound used to acquire the diagnostic image, the tissue tomographic image could not be acquired while the therapeutical ultrasound is irradiated, because of the reflection waves and the scattering waves caused by the therapeutical ultrasound. As a result, while the conventional therapy apparatus is employed, the suddenly-occurring positional sh
Azuma Takashi
Ishida Kazunari
Kawabata Ken-ichi
Kubota Jun
Kuroda Katsuhiro
Fuqua Shawntina T.
Mattingly Stanger & Malur, P.C.
Walberg Teresa
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