Melanoma Lymphoscintigraphy: The Immediate Image
Provided clinical image
Question
This melanoma lymphoscintigraphy shows two images side by side: an immediate image taken right after the peritumoral injection and an anterior 45-minute delayed image. What is the PRIMARY purpose of obtaining the IMMEDIATE image?
- ATo measure leftover activity in the syringe and calculate the exact dose administered to the patient
- BTo image the blood flow phase of the radiotracer as it enters the lymphatic system from the injection site
- CTo check that the patient is properly positioned in the field of view before the delayed images are acquired
- DTo confirm the injection was successful and mark the primary tumor site so it can be distinguished from sentinel nodes on delayed images
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D. To confirm the injection was successful and mark the primary tumor site so it can be distinguished from sentinel nodes on delayed images
The immediate image in lymphoscintigraphy serves as documentation that the tracer was successfully injected at the correct site (around the melanoma or biopsy scar). It establishes the baseline injection site location so that when sentinel nodes appear on delayed images, the technologist and surgeon can clearly distinguish nodes from the injection site. It also helps the surgeon understand the anatomical relationship between the primary tumor and the draining sentinel nodes.
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