How do I write a referral for a Positron Emission Tomography (PET) scan for a patient who needs to undergo the scan at a different location?

Writing a PET Scan Referral for a Different Location

When writing a new referral for a PET scan at a different location, you must provide comprehensive clinical information including the patient's diagnosis, specific clinical question to be answered, relevant medical history, current medications, recent imaging results, and treatment history to justify the examination.

Essential Components of the PET Scan Referral

Patient Demographics and Identification

• Include full patient name, date of birth, medical record number, height, and weight (weight is mandatory for standardized uptake value [SUV] measurements) 1
• Document contact information for both patient and referring provider 1

Clinical Information Required

Diagnosis and Clinical Question:

• State the specific diagnosis clearly 1
• Define the explicit clinical question(s) that the PET/CT examination needs to answer 1
• Specify the reason for referral and what clinical decision depends on the imaging results 1

Medical History:

• Document oncological history including known tumor sites and any extramedullary disease 1
• Include relevant co-morbidities: chronic kidney disease, allergies, thyroid dysfunction, infectious or inflammatory diseases, other tumors 1
• Note any history of trauma or fractures 1

Treatment History (Critical for Interpretation)

Recent Therapeutic Interventions:

• Type and date of last treatment (chemotherapy, immunotherapy, radiation, surgery) 1
• Current medications, especially antidiabetic medications, corticosteroids, growth factors, and sedatives 1
• Important timing consideration: A minimum delay of 1 month after radiotherapy or surgery is recommended before PET imaging to reduce false positive results from inflammation 1
• For post-surgical patients, delay PET/CT for at least 6 weeks if assessing the surgical field 1

Prior Imaging Documentation

Previous Studies:

• Provide dates and comprehensive reports from prior imaging (X-rays, CT, MRI, bone scans, previous PET/CTs) 1
• When feasible, include DICOM information from previous studies for comparison purposes 1
• Specifically note the previous PET scan order and why it needs to be performed at the new location 1

Clinical Symptoms and Physical Findings

Current Presentation:

• Document specific symptoms: pain location, fractures, night sweats, fatigue, fever 1
• Note any recent epileptic seizures (can cause false positive results on amino acid PET scans) 1
• Include relevant physical examination findings that prompted the imaging request 1

Laboratory Values

Required Lab Data:

• Recent serum glucose level (fasting status if known) 1
• Serum creatinine and estimated glomerular filtration rate if contrast may be used 1
• Other relevant labs: calcium, alkaline phosphatase (for bone involvement), liver function tests 1

Specific Considerations by Clinical Indication

For Staging or Restaging

• Specify the stage of disease if known 1
• Indicate whether this is initial staging, restaging after treatment, or evaluation for recurrence 1
• Note any suspicious findings on conventional imaging that require PET correlation 1

For Treatment Response Assessment

• Document the treatment regimen and dates of administration 1
• Provide baseline imaging for comparison 1
• Note the clinical question regarding response versus progression 1

Practical Referral Format

Your referral letter should include:

1. Header: Patient demographics, referring provider information, receiving facility details
2. Clinical summary: Brief diagnosis and reason for PET scan at new location
3. Relevant history: Oncological history, treatment timeline, prior imaging dates
4. Current status: Symptoms, physical findings, recent labs (especially glucose)
5. Specific clinical question: What decision will this scan inform?
6. Justification: Why the scan is medically necessary at this time 1
7. Reimbursement information: Include any insurance pre-authorization details 1

Common Pitfalls to Avoid

• Insufficient clinical information: Vague referrals like "PET scan for cancer staging" without specific diagnosis or clinical question may delay scheduling 1
• Missing timing considerations: Not accounting for the 4-6 week delay needed after surgery or radiation can result in false positive scans 1
• Incomplete medication list: Failing to document antidiabetic medications or recent corticosteroids affects scan interpretation 1
• No prior imaging documentation: Without comparison studies, the interpreting physician cannot assess interval changes 1

The key is treating this as a new patient referral with complete information rather than assuming the new facility has access to previous records, even though a prior order exists elsewhere 2.