Medical device

An image-acquiring medical device insertable into a body lumen to acquire images inside the body lumen, the image-acquiring medical device comprising:

• a shaft main body portion possessing a distal end at one end of the shaft main body portion and a proximal end at an opposite end of the shaft main body portion, the shaft main body including two lumens extending throughout a length of the shaft main body portion from the distal end of the shaft main body portion to the proximal end of the shaft main body portion, the two lumens of the shaft main body being separated from one another along the length of the shaft main body portion by a wall, the two lumens in the shaft main body comprising an image acquiring lumen for acquiring images and a guide wire lumen for receiving a guide wire;
• a proximal portion of the shaft main body including a first shaft proximal portion, in which a portion of the image acquiring is disposed, and a second shaft proximal portion, in which a portion of the guide wire lumen is disposed, the first shaft proximal portion and the second shaft proximal portion being bifurcated;
• a shaft distal portion connected to the distal end of the shaft main body, the shaft distal portion possessing an open distal end and an open proximal end, the shaft distal portion including a lumen that extends from the open proximal end of the shaft distal portion to the open distal end of the shaft distal portion, the open proximal end of the shaft main body communicating with both the guide wire lumen and the image acquiring lumen so that a guide wire is guidable along the lumen in the shaft main body and along the lumen in the shaft distal portion while extending distally beyond the open distal end of the shaft distal portion and proximally beyond a proximal end of the second shaft proximal portion;
• a hub that includes a first hub portion interlocked with the first shaft proximal portion and a second hub portion interlocked with the second shaft proximal portion the first hub portion possessing a central axis and the second hub portion possessing a central axis;
• a drive shaft rotatably positioned in the image acquiring lumen and axially movable in the image acquiring lumen, the drive shaft possessing a distal end;
• a transducer unit configured to acquire images, the transducer unit being fixed to the distal end of the drive shaft so that axial and rotational movement of the drive shaft results in axial and rotational movement respectively of the transducer unit;
• and
• the shaft main body portion possessing an axis line constituting a reference line, an inclination of the central axis of the first hub portion with respect to the reference line being represented by an angle θ1, an inclination of the central axis of the second hub portion with respect to the reference line being represented by θ2, and a relationship of |θ1|>|θ2| being satisfied.

A method of fabricating a medical device comprising:

• linearly stretching a first tube made of plastic material to produce a stretched first tube;
• heating a portion of the stretched first tube as well as a portion of a second plastic tube positioned adjacent the stretched first tube while pressing the portion of the stretched first tube and the portion of the second plastic tube against each other to heat-welded the portion of the stretched first tube and the portion of the second plastic tube to one another to integrate the portion of the stretched first tube and the portion of the second plastic tube to thereby produce a shaft main body portion;
• the heating of the portion of the stretched first tube as well as the portion of a second plastic tube also including not heating a proximal portion of the stretched first tube and not heating a proximal portion of the second plastic tube so that the proximal portion of the stretched first tube is not heat-welded to the proximal portion of the second plastic tube, the proximal portion of the stretched first tube that is not heated including a transducer lumen configured to receive a transducer for acquiring images in a living body, the proximal portion of the second tube that is not heated including a guide wire lumen configured to receive a guide wire;
• interlocking a first hub portion to the proximal portion of the stretched first tube in an airtight manner, and interlocking a second hub portion with the proximal portion of the second plastic tube, the first hub portion possessing a central axis and the second hub portion possessing a central axis different from the central axis of the first hub portion;
• covering the first hub and the second hub portion with a hub casing so that the proximal portion of the stretched first tube that is not heated and the proximal portion of the second tube that is not heated are bifurcated;
• and
• an axis line of the shaft main body portion is a reference line, θ1 represents an angle of inclination of the central axis of the first hub portion with respect to the reference line and θ2 represents an angle of inclination of the central axis of the second hub portion with respect to the reference line, and a relationship of |θ1|>|θ2| is satisfied.