Indications and Referrals for PET Scans

*ARVC/AIC

Indication: Patients with ventricular arrythmias in the setting of unexplained cardiomyopathy.

• Eligibility criteria: Ventricular arrhythmias in the setting of unexplained, non ischemic cardiomyopathy. Electrophysiology investigations and consults required.

*Device Infections

Indication: PET for the diagnosis and clinical management of patients with suspected infection of pacemaker, implantable cardioverter-defibrillator (ICD), cardiac resynchronization therapy (CRT), or left ventricular assist devices (LVAD).

• Eligibility criteria: High clinical suspicion and/or laboratory evidence of infection of generator pocket and/or endovascular lead infection. Clinical signs of infection of the ICD pocket or suspected extra-cardiac complications (septic emboli) with abnormal findings on echocardiogram.

*Graft Infection

Indication: PET for the diagnosis and clinical management of patients where there is a high clinical suspicion and/or laboratory evidence of infection of aortic and iliac grafts.

• Eligibility criteria: Definite graft infection with suspicion of extra-cardiac complications (septic emboli) or cardiac complications (perivalvular abscess). High clinical suspicion for infected graft (including positive blood culture).

*Pericarditis

Indication: PET for the diagnosis and clinical management of patients where there is a high clinical suspicion or lab evidence of pericarditis.

• Eligibility criteria: Persistent symptoms despite two weeks of adequate therapy. Recurrent pericarditis/symptoms despite adequate treatment of the initial episode. To assess response to therapy four weeks after therapy initiation.

*Myocarditis

Indication: PET for the diagnosis and clinical management of patients where there is a high clinical suspicion and/or laboratory evidence of myocarditis.

• Eligibility criteria: Recurrent symptoms or lack of LV function recovery despite adequate treatment of the initial episode. Persistent elevated troponin levels. Chest pain or shortness of breath, signs and symptoms of myocarditis post mRNA vaccine where knowledge of extent of inflammation would change management.

*Vasculitis/Aortitis

Indication: PET for the diagnosis and determination of clinical management of patients where there is a high clinical suspicion and/or laboratory evidence of vasculitis/aortitis.

• Eligibility criteria: Large vessel vasculitis (LVV) or similar with or without polymyalgia rheumatica (PMR) with high clinical suspicion including elevated inflammatory biomarkers with negative or equivocal imaging or biopsy workup. Patients with previous history of treated aortitis/vasculitis with new symptoms or elevation of inflammatory biomarkers.

*Other

Indication: Cardiac Special Access Program will consider other cardiovascular infection or inflammation processes on a case-by-case basis.

• Eligibility criteria: Other cardiovascular infection or inflammation processes, not listed above, may be considered such as assessment of cardiac masses, rheumatologic disorders or systemic multiple differential inflammatory diagnoses based on MRI/CT imaging. Compelling evidence demonstrating the need for FDG PET imaging should be provided for review.

Referral information: Download the Infection and Inflammation (Cardiac Special Access) Requisition Form.

*Case-by-Case Review Indication – Ontario Health collects data from these indications through the Cardiac Special Access Program to strengthen the evidence supporting the use of PET scans in Ontario.

Indication: PET for patients with definite diagnosis of IE, based on:

• Eligibility criteria: Duke International Society of Cardiovascular Infectious Diseases (ISCVID) criteria, to assess septic embolization.
  • Requirements: 2 major criteria or 1 major and 3 minor criteria or 4 minor criteria.

Indication: PET for patients with possible diagnosis of IE, based on:

• Eligibility criteria: Duke ISCVID criteria, to detect valvular/cardiac uptake (to confirm diagnosis) and septic embolization.
  • Requirements: criteria based on 2023 Duke criteria and European Society of Cardiology (ESC) guidelines.

Major criteria include:

• Positive blood cultures or positive polymerase chain reaction (PCR) for specific bacteria
• Echocardiography findings suggestive of IE (new vegetation valvular perforation or aneurysm, new significant valvular regurgitation or partial dehiscence of prosthetic valve)

Minor criteria include:

• Predisposition factors (previous history of IE, prosthetic valve previous valve repair or cardiac implantable electronic device (CIED) congenital heart disease or drug use)
• Fever >38 degrees Celsius
• Septic emboli
• Blood cultures or PCR positive for bacteria other than the one under major criteria

Referral information: Download the Infective Endocarditis Requisition Form.

For patients who do not meet the above infective endocarditis indications, apply for a PET scan through the Cardiac Special Access Program for the eligibility criteria listed below.

*Special Access – Infective Endocarditis

• Eligibility criteria: Rejected infective endocarditis with high clinical suspicion, concerns about extra-cardiac complications or perivalvular abscess.
• Cases that do not meet the specific Duke/ESC criteria as outlined above.

Referral information: Download the Infection and Inflammation (Cardiac Special Access) Requisition Form for details.

*Case-by-Case Review Indication – Ontario Health collects data from these indications through the Cardiac Special Access Program to strengthen the evidence supporting the use of PET scans in Ontario.

Eligibility criteria:

• Stress PET for the assessment of patients with known or suspected coronary artery disease (CAD) with an intermediate (10% to 90%) pre-test likelihood of significant ischemia secondary to coronary stenosis where:
  • there is a high likelihood of attenuation artifact with SPECT imaging or
  • a high degree of functional accuracy or quantitative flow measurements is required or
  • functional imaging is required and a low radiation dose is preferable (such as younger patients) or
  • the results of prior non-invasive imaging are equivocal or inconclusive or
  • in patients with known CAD where the need for intervention is uncertain

• Quantitative PET flow imaging may be particularly helpful when there is a need for absolute MBF measurements, such as:
  • patients without known CAD who present with symptoms suspect for ischemia
  • patients with known CAD, where specific physiological assessment is desired
  • identifying patients with an increased suspicion for multivessel CAD
  • to assess possible microvascular dysfunction
  • heart transplant patients when there is a question of vasculopathy

Referral information: Contact one of the following locations directly to refer your patient for a PET scan related to this indication.

• University of Ottawa Heart Institute
• St. Joseph's Health Care in Hamilton
• University Health Network in Toronto
• Health Sciences North in Sudbury

Indication: PET for myocardial viability assessment.

• Eligibility criteria: PET in a patient being considered for cardiac revascularization, cardiac transplantation, or other cardiac procedures with either: moderate to severe ischemic left ventricular dysfunction (left ventricular ejection fraction of 40% or less) despite maximal therapy; or moderate to severe persistent perfusion abnormality without significant (moderate or severe) ischemia.

Referral information: Download the Myocardial Viability Assessment Form

For patients who do not meet the above indication for myocardial viability assessment, apply for a PET scan through the Cardiac Special Access Program for the eligibility criteria listed below.

*Special Access – Myocardial Viability Assessment

• Eligibility criteria: PET in a patient being considered for cardiac revascularization, cardiac transplantation, or other cardiac procedures with either: moderate to severe ischemic left ventricular dysfunction (left ventricular ejection fraction of greater than 40%) despite maximal therapy; or moderate to severe persistent perfusion abnormality without significant (moderate or severe) ischemia.

Referral information: Download the Myocardial Viability Assessment (Cardiac Special Access) Requisition Form.

*Case-by-Case Review Indication – Ontario Health collects data from these indications through the Cardiac Special Access Program to strengthen the evidence supporting the use of PET scans in Ontario.

Eligibility Criteria: Amyloid PET for patients with a diagnosis of mild cognitive impairment (MCI) or dementia, according to DSM IV and/or National Institutes of Aging Alzheimer’s Association criteria, verified by a dementia specialist within the past 24 months.

Special Considerations: Amyloid PET imaging should only be considered in patients with clear, measurable cognitive deficits when Alzheimer’s disease is a consideration and in whom knowledge of amyloid status is expected to change management.

Note: A dementia specialist can include a neurologist, geriatrician, geriatric psychiatrist, and/or primary care physician in a memory clinic.

Referral Information: Download the Amyloid PET Registry Requisition Form and the Amyloid PET Registry Pre-PET Patient Questionnaire 

*Registry Indication – Ontario Health collects data from these indications to strengthen the evidence supporting the use of PET scans in Ontario.

Esophageal or Gastroesophageal (GE) Junction
Eligibility criteria: PET for baseline staging assessment of those patients diagnosed with esophageal/GE Junction cancer being considered for curative therapy and/or repeat PET/CT scan on completion of pre-operative/neoadjuvant therapy, prior to surgery; or for re-staging of patients with locoregional recurrence, after primary treatment, being considered for definitive salvage therapy.

Colorectal (apparent limited metastatic)
Eligibility criteria: PET for the staging or re-staging of patients with apparent limited metastatic disease (for example, organ-restricted liver or lung metastases) or limited local recurrence, who are being considered for radical intent therapy.

As chemotherapy may affect the sensitivity of the PET scan, it is strongly recommended to schedule PET at least six weeks after last chemotherapy, if possible.

Colorectal (recurrent)
Eligibility criteria: PET where recurrent disease is suspected on the basis of an elevated and/or rising carcinoembryonic antigen (CEA) level(s) during follow-up after surgical resection but standard imaging tests are negative or equivocal.

Anal canal (staging or re-staging)
Eligibility criteria: PET for the initial staging of patients with stages II (two) to IV (four) squamous cell carcinoma of the anal canal or when conventional imaging is equivocal for a specific stage; or for re-staging of patients with limited recurrence, after primary treatment, being considered for definitive salvage therapy.

Referral Information: Download the Gastrointestinal Requisition Form.

Bladder (muscle invasive)

Eligibility criteria: PET for the staging of patients with newly diagnosed muscle-invasive urothelial carcinoma of the bladder being considered for curative intent treatment with either radical cystectomy or radiation-based bladder preservation therapy; TNM stage T2a-T4a, N0-3, M0.

Referral information: Download the Genitourinary Requisition Form.

Note: For patients with M1a or M1b disease, apply for a PET scan through the PET Access Program.

Penile

Eligibility criteria: 

• PET for baseline staging assessment of patients diagnosed with penile cancer and clinically node positive disease, being considered for curative therapy;
• PET for re-staging of patients with locoregional recurrence, after primary treatment, being considered for definitive salvage therapy; TNM stage T1b-T4, N1-3, M0.

Referral information: Download the Genitourinary Requisition Form.

Note: For patients with M1a or M1b disease, apply for a PET scan through the PET Access Program.

Germ cell tumours (recurrent/persistent disease)

• Eligibility criteria:
  • PET where recurrent disease is suspected on the basis of elevated tumour marker(s) - (beta human chorionic gonadotrophin (HCG) and/or alpha fetoprotein) and standard imaging tests are negative or
  • Where persistent disease is suspected on the basis of the presence of a residual mass after primary treatment for seminoma when curative surgical resection is being considered

Referral information: Download the Genitourinary Requisition Form .

Prostate (PSMA PET)

• Eligibility criteria: Prostate Specific Membrane Antigen (PSMA) PET in the following patient populations:
  • Initial staging of patients with unfavourable intermediate risk OR high-risk prostate cancer when radical radiotherapy is being considered or
  • Staging of patients with recurrent prostate cancer who fall into one of the following pre-defined indications:
    • Post-prostatectomy node positive disease or persistently detectable PSA
    • Biochemical failure post-prostatectomy
    • Biochemical failure following radical prostatectomy followed by adjuvant or salvage radiotherapy
    • Biochemical failure while on salvage androgen deprivation therapy after radical prostatectomy (with or without adjuvant or salvage radiotherapy)
    • Biochemical failure after treatment for PSMA PET/CT-identified disease
    • Biochemical failure following primary radiotherapy
    • Rising PSA and/or progression on conventional imaging despite prior androgen receptor pathway inhibitors and chemotherapy for castrate resistant prostate cancer, being considered for publicly funded radioligand therapy.

Referral information: Download the Ga-68 PSMA PET for Prostate Cancer Requisition Form (pdf).

Note: Apply for a PSMA PET scan for case-by-case review through the PET Access Program, for when the PET scan is a problem-solving tool, where the confirmation of the site of disease and/or disease extent may impact clinical management over and above the information provided by conventional imaging.

Cervical cancer (staging)

• Eligibility criteria: PET for the staging of locally advanced cervical cancer when:
  • CT/MRI shows positive or indeterminate pelvic nodes (greater than 7 millimetres and/or suspicious morphology) or
  • CT/MRI shows borderline or suspicious para-aortic or
  • CT/MRI shows suspicious or indeterminate distant metastases (for example, chest nodules)

Gynecology (recurrent, prior to salvage therapy)
Eligibility criteria: PET for re-staging of patients with recurrent gynecologic malignancies under consideration for radical salvage surgery (for example, pelvic exenteration)

Referral Information: Download the Gynecology Requisition Form.

Unknown primary
Eligibility criteria: PET for the evaluation of metastatic squamous cell carcinoma in neck nodes when the primary disease site is unknown after standard radiologic and clinical investigation.

A panendoscopy is not required prior to the PET scan.

Nasopharyngeal (baseline staging)
Eligibility criteria: PET for the staging of nasopharyngeal cancer.

For cervical esophageal cancer, refer to Gastrointestinal Cancers.

Head and Neck node positive (baseline staging)
Eligibility criteria: PET for the baseline staging of node positive (N1-N3) head and neck cancer where PET will impact radiation therapy (for example, radiation volume or dose)

Head and Neck (re-staging after chemoradiotherapy)
Eligibility criteria: PET to assess patients with N1-N3 metastatic squamous-cell carcinoma of the head and neck after chemoradiation (HPV negative); or who have residual neck nodes equal to or greater than 1.5 centimetres on re-staging CT performed 10 to 12 weeks post therapy (HPV positive).

Thyroid (recurrent)
Eligibility criteria: PET where recurrent or persistent disease is suspected on the basis of elevated and/or rising tumour markers (for example, thyroglobulin) with negative or equivocal conventional imaging work-up.

Anaplastic Thyroid (staging)
Eligibility criteria: PET for the staging of histologically proven anaplastic thyroid cancer with negative or equivocal conventional imaging work-up.

Medullary Thyroid (staging and recurrent)
Eligibility criteria: PET for the baseline staging of histologically proven medullary thyroid cancer being considered for curative intent therapy or where recurrent disease is suspected on the basis of elevated and/or rising tumour markers (for example, calcitonin) with negative or equivocal conventional imaging work-up.
Complete the Ga68-DOTATATE PET Requisition Form if you’d prefer your patient receive a Ga68DOTATATE PET scan instead of an FDG PET scan

Esophageal or Gastroesophageal (GE) Junction
Eligibility criteria: PET for baseline staging assessment of those patients diagnosed with esophageal/GE Junction cancer being considered for curative therapy and/or repeat PET/CT scan on completion of pre-operative/ neoadjuvant therapy, prior to surgery; or for re-staging of patients with locoregional recurrence, after primary treatment, being considered for definitive salvage therapy.

Referral Information: Download the Head and Neck PET Requisition Form.

Histiocytic

• Eligibility criteria:
  • Baseline staging FDG PET for histiocytic disorders
  • Interim response assessment FDG PET: After three to six months of therapy
  • End of therapy response assessment FDG PET: For the evaluation of residual mass(es) or lesion(s) (e.g., bone) following therapy in patients with histiocytic disorders
  • Restaging FDG PET for histiocytic disorders – clinical suspicion of relapse

Referral Information: Download the Histiocytic Disorder Requisition Form.

 

Lymphoma

• Eligibility criteria:
  • Staging: PET for the baseline staging of patients with lymphoproliferative disorders (adults and pediatrics)
  • Interim response assessment for Hodgkin lymphoma: PET for the assessment of response in Hodgkin lymphoma following two or three cycles of chemotherapy when curative therapy is being considered (adults and pediatrics)
  • *Interim response assessment for stage 1 or 2 non-Hodgkin lymphoma after three cycles of chemotherapy for patients being considered for de-escalation of therapy (adults and pediatrics)
  • Interim response assessment for non-Hodgkin lymphoma (pediatrics only, under 18 years old; or 18 to 20 years old and treated at a pediatric centre): PET for the assessment of response in non-Hodgkin lymphoma after a minimum of two cycles of chemotherapy when curative therapy is being considered
  • End of therapy response assessment (adults and pediatrics):
    • PET for the evaluation of residual mass(es) or lesion(s) (for example, bone) following chemotherapy in patients with lymphoproliferative disorders when further potentially curative therapy (such as radiation or stem cell transplantation) is being considered; or
    • PET to assess response to chimeric antigen receptor (CAR) T-cell therapy, thirty (30) days or ninety (90) days post transfusion.

Referral information: Download the Lymphoma Requisition Form.

*Registry Indication – Ontario Health collects data from these indications to strengthen the evidence supporting the use of PET scans in Ontario.

 

*Myeloma or plasmacytoma

• Eligibility criteria: To evaluate the impact of PET on the management of patients with plasmacytoma or myeloma for the following indications:
  • Solitary plasmacytoma: For patients with presumed solitary plasmacytoma who are candidates for curative intent radiotherapy (to determine whether solitary or multifocal/extensive disease)
  • Smoldering myeloma: Workup of patients with smoldering myeloma (to determine whether smoldering or active myeloma)
  • Nonsecretory myeloma, oligosecretory myeloma, or POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes): Baseline staging and response assessment
  • Newly-Diagnosed Secretory Multiple Myeloma: Workup of patients with newly-diagnosed secretory multiple myeloma

Referral information: Download the Multiple Myeloma/Plasmacytoma Requisition Form.

*Registry Indication – Ontario Health collects data from these indications to strengthen the evidence supporting the use of PET scans in Ontario.

• Eligibility criteria:
  Diagnosis:
  • PET for the evaluation of a pancreatic, small bowel or mesenteric mass with findings suggestive of a NET (for example, hypervascular pancreatic mass, desmoplastic mesenteric mass) on conventional imaging
  • PET for the evaluation of extra-adrenal mass (for example, carotid body nodule), with conventional imaging and/or elevated biomarkers suggestive of a pheochromocytoma/paraganglioma (PPGL)
  • PET for a patient with a genetic syndrome predisposing to NETs and a biochemical and/or morphological suspicion of a NET in whom PET results would measurably impact management

  Special considerations for diagnosis:

  • Patients with a suspicious mass in another anatomical location (for example, lung) without elevated biochemical markers should be considered for further workup and/or biopsy before the PET. PET could be considered after a failed biopsy or if a biopsy is not feasible.
  • Patients with a pancreatic tail mass suggestive of a NET should have a Tc-99m Sulpha Colloid or Red Blood Cell scan to exclude intrapancreatic accessory spleen as both can present Ga-68 DOTATATE avid.

  Initial staging (initial staging PET scans should be requested within one year from the initial diagnosis):

  • PET for a histologically proven well-differentiated NET (G1-G3), including unknown primary, or pheochromocytoma/paraganglioma (PPGL)
  • PET for a histologically proven medullary thyroid cancer being considered for curative intent therapy

  Special considerations for initial staging:

  • PET is not appropriate for patients with Type 1 Gastric NET, neuroendocrine carcinomas (NEC) and adenocarcinomas with NET features.
  • Unless there are unique clinical and/or structural concerns, PET is not routinely appropriate for patients with Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH).
  • PET for the initial staging of a patient with an appendiceal NET should be considered when there are positive lymph nodes, the tumour is greater than 1 centimetre, and/or the tumour is invading through the serosa into the mesoappendix.

• PET for the initial staging of a patient with medullary thyroid cancer should be considered when the patient has yet to have a thyroidectomy or following it when biomarkers are positive with negative or equivocal structural imaging.

  Re-staging:

  • PET for a patient with progressive NETs disease and is being considered for publicly funded Peptide Receptor Radionuclide Therapy (PRRT).
    For PRRT consideration, a PET scan should be completed within 12 months. However, a more recent PET scan should be considered if there are concerning clinical features (for example, de-differentiation).
  • New baseline PET scan for patients with new metastatic disease on conventional imaging and/or clinical suspicion of de-differentiation.
  • PET for a patient with medullary thyroid cancer when recurrent disease is suspected on the basis of elevated and/or rising tumour markers (e.g., calcitonin), with negative or equivocal conventional imaging work-up

  • The following are preliminary indications and are likely to be refined:

  • PET for a patient with NETs disease when surgery (for example, de-bulking, focal ablation, liver-directed therapy) is being considered.
  • PET for a patient with NETs disease where conventional imaging is negative or equivocal at the time of clinical and/or biochemical progression.

  Special considerations for routine surveillance:

  • Requests for routine surveillance when there is no clinical or biochemical suspicion of recurrence or progression are not eligible.

Referral information: Download the Ga68-DOTATATE PET Requisition Form.

Sarcoma (initial staging/re-staging)
Eligibility criteria: PET for the initial staging of patients with histologically confirmed high grade (equal to or greater than grade 2), or ungradable, soft tissue or bone sarcomas, when conventional workup is negative or equivocal for metastatic disease, prior to curative intent therapy; or for re-staging of patients with suspicion of, or histologically confirmed, recurrent sarcoma (local recurrence of limited metastatic disease) when radical salvage therapy is being considered.

Plexiform Neurofibromas (diagnosis)
Eligibility criteria: PET for patients with suspicion of malignant transformation of plexiform neurofibromas.

Referral Information: Download the Sarcoma Requisition Form.

Esophageal or Gastroesophageal (GE) Junction
Eligibility criteria: PET for baseline staging assessment of those patients diagnosed with esophageal/GE Junction cancer being considered for curative therapy and/or repeat PET/CT scan on completion of pre-operative/ neoadjuvant therapy, prior to surgery; or for re-staging of patients with locoregional recurrence, after primary treatment, being considered for definitive salvage therapy.

Lung - non-small cell lung cancer (NSCLC; clinical stage 1 to 4)
Eligibility criteria:

• PET for initial staging of patients with NSCLC  being considered for potentially curative therapy or
• For re-staging of patients with locoregional recurrence, after primary treatment, being considered for definitive salvage therapy
• for staging of patients with oligometastatic NSCLC being considered for definitive local therapy.

Histological proof is not required prior to PET if there is high clinical suspicion for NSCLC (for example, based on patient history and/or prior imaging).

PET is appropriate for patients with either histological proof of locoregional recurrence or strong clinical and radiological suspicion of recurrence who are being considered for definitive salvage therapy.

Lung - small cell lung cancer (SCLC; clinical stage 1 to 3)

• Eligibility criteria: PET for initial staging of patients with limited disease SCLC where combined modality therapy with chemotherapy and radiotherapy is being considered.

Lung - solitary pulmonary nodule (SPN)

• Eligibility criteria: PET for a semi-solid or solid lung nodule for which a diagnosis could not be established by a needle biopsy due to unsuccessful attempted needle biopsy; the SPN is inaccessible to needle biopsy; or the existence of a contra-indication to the use of needle biopsy.

Lung - mesothelioma

• Eligibility criteria: PET for the staging of patients with histologic confirmation of malignant mesothelioma.

Referral Information: Download the Thoracic Requisition Form.

*Pediatric Oncology Registry

• Eligibility criteria: Pediatric Registry Indications (data collection/partnership with the Pediatric Oncology Group of Ontario):
  • For the following cancer types (ICCC - International Classification of Childhood Cancer):
    • Bone/cartilage - osteosarcoma, Ewing sarcoma
    • Connective/other soft tissue - rhabdomyosarcoma, other
    • Kidney - renal tumour
    • Liver - hepatic tumour
    • Primary brain - astrocytoma, medulloblastoma, ependymoma, other
    • Reproductive - germ cell tumour
    • Sympathetic nervous system - neuroblastoma MIBG negative
    • Other - LCH, melanoma of the skin, thyroid
  • For the following indications:
    • Initial staging
    • Monitoring response during treatment or determine response-based therapy
    • Rule out progression prior to further therapy
    • Suspected recurrence or relapse
    • Rule out persistent disease
    • Select optimal biopsy site

Referral information: To submit Pediatric Oncology Registry referrals, you must log in to the PET Scans Ontario E-Tool.

*Registry Indication – Ontario Health collects data from these indications to strengthen the evidence supporting the use of PET scans in Ontario.