The present disclosure relates generally to positioning elongate members at a target site within a body lumen, such as for acquiring a biopsy from a peripheral airway. Some embodiments are particularly directed to an elongate member with an embedded transducer positioned at a predefined rotational angle with respect to a projected position of an instrument extended out of a distal opening of a first lumen in the elongate member. In many such embodiments, a rotational transducer may be positioned within a second lumen in the elongate member to generate a radial image including indicia of the embedded transducer. Accordingly, an operator may determine a projected position of the instrument prior to extending the instrument out of the lumen. In several embodiments, the embedded transducer may include a forward imaging transducer, such as a fiber optic.