Treatment method and medical device

A treatment method comprising:

• introducing a sheath of a catheter into a biological lumen of a living body and in a direction toward a stenosed site in the biological lumen;
• advancing a distal tip of the sheath from a proximal side of the stenosed site in the biological lumen through the stenosed site to a distal side of the stenosed site in the biological lumen;
• positioning, while a portion of the sheath is disposed in the stenosed site, a shaft disposed inside a lumen of the sheath at a postion of the stenosed site;
• withdrawing the sheath from the stenosed site while maintaining the shaft in the position of the stenosed site, wherein withdrawing the sheath exposes a portion of the shaft form the lumen of the sheath such that i) a dilation balloon portion of the shaft is arranged in the stenosed site, ii) a removal portion of the shaft comprising a plurality of protruding portuions is disposed on the distal side of the stenosed site, and iii) the sheath is disposed on the proximal side of the stenosed site, and wherein the plurality of protruding portions are capable of removing a secretion secreted from the biological lumen in the stenosed site;
• widening the stenosed site by dilating the dilation balloon portion of the shaft while arranged in the stenosed site;
• deflating the dilation balloon portion of the shaft while arranged in the stenosed site;
• and
• removing the secretion from the biological lumen by moving the plurality of protruding portions from the distal side of the stenosed site into contact with the secretion in the stenosed site entrapping the secretion in the plurality of protruding portions and then moving the plurality of protruding portions and the secretion entrapped therein from the stenosed site to the proximal side of the stenosed site.