A medical device (100) for disrupting substances in a body lumen faces a rotatable tubular drive shaft (114) and a treatment member (102) connected to the drive shaft (114). A tubular member (160) having a distal end and a proximal end, the tubular member (160) having an axially extending lumen for passage of a guidewire. The tubular member (160) is disposed within the lumen tip of the treatment member (102). The tubular member (160) has an axial length from the most proximal end of the tubular member (160) to the most distal end of the tubular member (160). The axial length of the tubular member (160) is shorter than the axial length of the treatment member (102), and the treatment member (102) and the tubular member (160) are relatively rotatable.身体の内腔内の物質を粉砕するための医療用デバイス（１００）は、回転可能な管状の駆動シャフト（１１４）と、駆動シャフト（１１４）に接続された処置部材（１０２）と、対向する最先端部および最基端部を有する管状部材（１６０）とを含み、管状部材（１６０）は、ガイドワイヤを通せるように軸方向に延在するルーメンを有する。管状部材（１６０）は、処置部材（１０２）のルーメンの先端部内に配置される。管状部材（１６０）は、管状部材（１６０）の最基端部から管状部材（１６０）の最先端部までの軸方向長さを有する。管状部材（１６０）の軸方向長さは、処置部材（１０２）の軸方向長さよりも短く、処置部材（１０２）および管状部材（１６０）は、相対的に回転可能である。
