Ga68 PET Scan
The Gallium 68 scan, used with functional PET imaging, is another nuclear medicine scan that relies on the over-expression of somatostatin receptors to visualize tumours. NETs typically express several somatostatin receptor subtypes in a unique pattern based on tumour type, origin and grade of differentiation. Ga68 scans offer the advantages of improved image resolution and higher sensitivity.
Tumours that may be visualized with a Ga68 scan include: gastroenteropancreatic (GEP) tumours; pheochromocytoma, paraganglioma, neuroblastoma, medullary thyroid carcinoma and others.
Prior to receiving a Ga68 scan ask your doctor whether or not you should discontinue somatostatin analog therapy. The radiopharmaceutical will be administered intravenously and the scan will be performed. The substances used to perform the Ga68 scan are rapidly cleared from the blood; therefore, no radioactivity is detectable in the blood or urine within four hours.
Why Ga68 PET for Neuroendocrine Cancer Patients?
Ga-68-labeled somatostatin analogs are important imaging agents to detect and manage neuroendocrine tumors (NETs). The Gallium 68 scan, used with functional PET imaging, is a nuclear medicine scan that relies on the over-expression of somatostatin receptors to visualize tumours. NETs typically express several somatostatin receptor subtypes in a unique pattern based on tumour type, origin and grade of differentiation. Ga68 scans offer the advantages of improved image resolution and higher sensitivity.
- Offers high quality images that provide information that exceeds what is available from conventional imaging (111In-Octreotide, contrast enhanced CT).
- Can detect tumors as small as 4 millimeters.
- Has different roles depending on what the tumour is doing.
- May be used for diagnosis, staging and restaging, deciding best form of treatment and monitoring the effect of treatment.
- Identifies patients who are viable candidates for PRRT therapy.
- Cost of scan is currently comparable to Octreotide and therefore no further burden on provincial funding agencies.
Change in Patient Management:
Ga68 has the potential to delineate the extent of disease accurately for proper management:
- Different studies found that Ga68 PET led to change in management in 36% to 56% of patients.
- Could spare patients from invasive futile surgery.
- Offers the ability to tailor treatments for patients based on a more accurate assessment of tumor burden.
- Potential to find unknown primary. Important for NET patients who have had surgery to remove metastases but have an unknown primary tumor.
- Earlier diagnosis for symptomatic patients.
- May also provide additional information, such as if a tumor is well or poorly differentiated. Poorly differentiated tumors are more aggressive and with the GA-68 scan the likelihood of a tumor’s growth may be determined.
- In one trial, patients who were previously considered to be inoperable went on to have surgery, and patients with previously unknown and extensive cancer who were originally slated for surgery were found to be inoperable.
- No significant toxicity
- Lower radiation exposure
- Shorter examination time
- Fewer visits to hospital with scan completed in one day as opposed to multiple days for Octreoscan
Access to Ga68 scan in Canada
Applying for Ga68 Scan in Sherbrooke, Quebec.
Ensure the referring physician indicates how the Ga68 PET scan may influence the clinical management of the patient.
Requests for elective medical services such as PET scans, provided in other provinces and territories that are not covered under the Interprovincial Reciprocal Billing Agreements, require prior approval by the British Columbia Ministry of Health. The Ministry requires and relies on the referring specialists and the appropriate authorities at various agencies and health authorities to confirm that an application for funding is appropriate.
If a specialist wants to refer a patient to Sherbrooke for a PET scan, the appropriateness of the request based on the established criteria for approving funding requests.
A referring specialist who is seeking pre-approval to send a patient to Sherbrooke for a PET scan, can submit their request to PCR@gov.bc.ca, and it will be considered for pre-approval.
Dr. Zeljko Bolesnikov
PO Box 5100
Fredericton, NB E3B 5G8
Fax: (506) 457-7671
Steps for the Process For Obtaining Approval for Ga-68 DOTATATE Scanning in Sherbrooke:
- The treating physician needs to confirm that the patient is eligible under the Sherbrooke CTA.
- If the patient is eligible, the referring physician contacts CCO’s PET Access Program for an application form, completes and submits to CCO (via online submission or secure fax) with supporting clinical documentation.
- The application package is screened and redacted by the PET Access Program and sent to a panel of three specialists (including imaging and NET treating physicians) for review.
- The panel may ask for additional documentation from the referring physician.
- The panel makes a recommendation.
- If they recommend approval, the PET Access Program notifies the referring physician to contact Sherbrooke to set up the appointment.
- The PET Access Program also contacts Sherbrooke to let them know that the request was approved.
- Turnaround times for this process are very quick – usually within 1-2 weeks (frequently sooner as long as the application package is complete).
PET Access Program
The Ontario PET Access Program considers, on a case-by-case basis, requests from physicians for the provision of PET scans for patients who may benefit, but who do not meet the eligibility criteria to receive PET scans under one of these other categories: insured services , the PET Registry or clinical trials .
Referring physicians need to confirm in the application that other diagnostic tests do not provide the clinical information needed, and indicate how a PET scan may influence the clinical management of the patient.
The Sherbrooke Study
Phase-II, prospective, open label, no control group to assess the safety of 68Ga-DOTA-TATE injection in patients with suspected or diagnosed with tumors expressing somatostatin receptors. Each included patient will receive an administered dose of 50 mcg or less of the peptide (DOTA-TATE) and a range of activity between 100 – 200 MBq of 68Ga-DOTA-TATE.
The efficacy of 68Ga-DOTA-TATE in assessing this kind of tumors has been proved by numerous studies.
• Patients with suspected or proven tumors expressing Somatostatin receptors
• Informed consent by patient (or parents if patient is less than 18 years of age)
• Pregnancy (confirmed). In the case of a diagnostic procedure in a patient who is or may be pregnant, a clinical decision is necessary considering the benefits against the possible harm of carrying out any procedure.
• Patient refusal to participate.
• Impossibility to tolerate a decubitus position for 25 minutes
• Prior allergic reaction to DOTA-TATE or somatostatin analogs
Centre hospitalier universitaire de Sherbrooke
Sherbrooke, Quebec, Canada, J1H 5N4