When monitoring blood oxygen levels in a patient during a magnetic resonance scan, detachable and reusable fiber optic cable heads (16, 18, 98, 131, 132) are coupled to an SpO2 monitor and to a hinged finger clip (40, 70, 90, 110, 190) on a patient. The finger clip (40, 70, 90, 110, 190) includes apertures (94, 196) and a retaining structure (44, 95, 198) to which a coupling portion of the fiber heads (16, 18, 98, 131, 132) are releasable attached. The retaining structure includes retaining clips (44, 198), slots (95), or the like that flexibly receive and align the fiber heads (16, 18, 98, 131, 132). The retaining structure (44, 95, 198) may be deformable, such that detachment of the fiber heads (16, 18, 98, 131, 132) at the end of the MR scan renders the finger clip (40, 70, 90, 110, 190) unusable to ensure that the clip is not reused, thereby preventing cross-infection between patients. Alternatively, the finger clip (40, 70, 90, 110, 190) may be reusable and the retaining clips may be designed to withstand repeated attachment and detachment of the fiber heads (16, 18, 98, 131, 132). A compressible foam or plastic layer is coupled to the interior of the clip portions to provide a snug fit. A transparent layer (54) attached to the foam or plastic layer permits light to pass through the foam/plastic aperture while preventing the fiber heads (16, 18, 98, 131, 132) from contacting the patient's skin.