Lymphoma
Melanoma
Head and Neck Cancer
Thyroid Cancer
Esophageal Cancer

Lymphoma

In a patient with Hodgkins lymphoma, the choice, whether to use radiation or chemotherapy, would generally be based on CT scans, which might not detect all sites of tumor. After therapy, a residual mass could represent scar or living tumor, but this is difficult to determine with CT.

Whole-body PET scans can locate lymphoma anywhere in the body. After treatment, PET can often determine with high reliability whether additional treatment is needed or if observation is appropriate.

This case shows intense tracer uptake in left chest nodes and pelvic nodes consistent with recurrence of Hodgkins disease.

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Melanoma

When a melanoma recurs, removal of the recurrent tumor can be curative. CT or MRI is often used to make this determination, but they may fail to detect all the lesions. Surgery may be performed and fail to remove the tumors that were not detected.

Using PET to survey the entire body, a precise delineation of the location of tumor masses in soft tissues can be achieved, allowing a more informed choice as to whether the tumor can be removed for cure.

This case shows a large right axillary focus of melanoma. Multiple metastases are also seen which were unexpected.

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Head and Neck Cancer

After this type of tumor is treated with surgery and/or radiation, the neck is quite distorted and it can be very difficult to determine by CT or MRI whether tumor has recurred, or if there is just scarring present.

With PET, the high metabolic activity of recurrent tumor can be detected non-invasively. Patients with recurrent tumor can be diagnosed. Recent direct comparative studies have shown PET to be significantly more accurate than MRI in this setting. PET is also a very useful tool in staging this tumor at the time of initial diagnosis.

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Thyroid Cancer

I-131 scans have been used for many years, but some tumors have low iodine uptake and are hard to detect. Patients can present with high serum markers indicating that the tumor has recurred, but it may not be localized by imaging.

Using FDG PET, thyroid cancers that don't accumulate iodine can be detected. In some instances, local recurrences can be surgically resected.

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Esophageal Cancer

This tumor is becoming more common. Upon diagnosis, the oncologist must determine how extensive the spread of the cancer may be to make the appropriate therapy decision.

Conventional anatomic methods such as CT or MRI may not completely identify all the sites. Recent studies have definitively shown that PET is more sensitive and more accurate than CT scans in detecting widespread esophageal tumors. MRI is also not particularly reliable in this setting. A PET scan translates into more accurate tumor staging for these patients.

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