Medical treatment device

1. A medical treatment device comprising:

an ultrasonic endoscope comprising an observation window, an illumination window, a treatment instrument opening and an ultrasonic transducer capable of transmitting and receiving an ultrasonic wave at a distal end portion of an insertion portion configured to be inserted into a body cavity, wherein a treatment instrument insertion channel is in communication with the treatment instrument opening provided in the insertion portion;

a guide tube inserted into the treatment instrument insertion channel of the ultrasonic endoscope and configured to be introduced into the body cavity;

a hollow needle pipe inserted into the guide tube;

a stylet, the stylet adapted to be inserted through the hollow needle pipe;

the hollow needle pipe, having an outer diameter, capable of being inserted into and removed from the guide tube, the hollow needle pipe capable of forming a puncture hole in a lesion;

a treatment probe having an electrode portion having an outer diameter larger than the outer diameter of the hollow needle pipe inserted into the guide tube, the treatment probe capable of being inserted into the puncture hole, the electrode portion including a first electrode and a second electrode insulated and separated from each other by an insulation portion for a radio-frequency cautery treatment for the lesion; and

an ultrasonic reflection portion for reflecting an ultrasonic signal emitted from the ultrasonic transducer of the ultrasonic endoscope toward the ultrasonic transducer, the ultrasonic reflection portion being formed on surfaces of the first electrode and the second electrode of the treatment probe,

wherein the hollow needle pipe comprises an ultrasonic reflective surface, the ultrasonic reflective surface having about the same length as a length of the electrode portion formed at the treatment probe and is arranged at a position corresponding to a position of the electrode portion,

wherein the ultrasonic reflective surface of the hollow needle pipe comprises a first reflection portion, a second reflection portion and a low reflection portion, an ultrasonic reflectivity of which is lower than an ultrasonic reflectivity of the first reflection portion and an ultrasonic reflectivity of the second reflection portion, the low reflection portion is provided between the first reflection portion and the second reflection portion, and a length of the first reflection portion, a length of the low reflection portion and a length of the second reflection portion are set to be about the same as a length of the first electrode, a length of the insulation portion and a length of the second electrode of the electrode portion of the treatment probe, respectively,

wherein the hollow needle pipe includes on the ultrasonic reflective surface thereof the ultrasonic portion for reflecting the ultrasonic signal emitted from the ultrasonic transducer of the ultrasonic endoscope toward the ultrasonic transducer, and

wherein the ultrasonic reflection portion is a recess and projection portion or a rough-surfaced potion.

2. The medical treatment device according to claim 1 , wherein a length from a distal-most end of a distal-end needle portion of the hollow needle pipe to a hollow needle pipe base is about the same as a length from a distal end of the first electrode to a base of a grasping portion.

3. The medical treatment device according to claim 1 , wherein the recess and projection portion of the ultrasonic reflection portion is a sucker-state, V-shaped groove or rectangular groove.