Method and system for imaging, diagnosing, and/or treating an area of interest in a patient's body

A method of using a manually steered rapid exchange catheter to image, diagnose, and/or treat an area of interest in a patient's body, comprising:

• introducing a guidewire to an area of interest in a patient's body;
• loading the manually steered rapid exchange catheter on the guidewire, the manually steered rapid exchange catheter comprising:
• a proximal portion;
• a distal portion including a guidewire passage having both an entry and exit;
• an imaging, diagnosing, and/or treating device positioned within the proximal portion, the device being manually rotated to affect steering of energy emitted by the device;
• and
• a rotational joint that couples the distal portion and the proximal portion
• advancing the manually steered rapid exchange catheter along the guidewire to the area of interest;
• and
• manually steering the manually steered rapid exchange catheter by rotating the imaging, diagnosing and/or treating device contained within the proximal portion of the manually steered rapid exchange catheter, while maintaining the distal portion rotationally stationary, to image, diagnose, and/or treat the area of interest.