Medical Policy



Subject: PET Scanning Using Gamma Cameras
Document #: RAD.00040 Current Effective Date:    06/28/2017
Status: Reviewed Last Review Date:    05/04/2017

Description/Scope

This document addresses positron emission tomography (PET) scanning using a gamma camera.  This technique uses a PET radiotracer, (for example, radio-labeled 2-fluoro-2 deoxy-D-glucose [FDG]), in conjunction with a single photon emission computed tomography (SPECT) gamma camera, instead of a dedicated PET scanner. A dedicated PET scanner consists of multiple detectors arranged in a full or partial ring around the individual, permitting the simultaneous detection of the high-energy paired positrons that are emitted at 180 degrees from one another. SPECT gamma cameras are conventionally used to provide scintigraphic studies, such as bone scans or cardiac thallium studies. When used in conjunction with FDG, specially equipped SPECT cameras can provide images reflecting the metabolic activity of tissues, similar to PET scanning.  

Note: This document describes a variant to a PET scan and does not address conventional SPECT scanning, which is addressed separately in RAD.00023 Single Photon Emission Computed Tomography (SPECT) Scans for Noncardiovascular Indications.

For additional indications for conventional PET and PET/computed tomography (CT) fusion testing, see:

Position Statement

Investigational and Not Medically Necessary:

All applications of PET scanning with a gamma camera are considered investigational and not medically necessary.

Rationale

A key consideration in the evaluation of PET scans using gamma cameras is the fact that the lower number of detectors in the SPECT approach, compared to the full or partial ring of detectors used in PET imaging, will result in a relative loss of sensitivity and resolution. Both oncologic and cardiac applications of this technology have been investigated.

Oncologic Applications
A variety of studies, focusing on the oncologic applications of PET scanning using gamma cameras, have consistently reported a decreased sensitivity for smaller lesions (less than 2 cm in diameter), compared to conventional PET scanning. There is inadequate data comparing the diagnostic performance of PET scanning using gamma cameras to either CT scans or magnetic resonance imaging (MRI).

A study of clinical management, based on results of fluorine-18 fluorodeoxyglucose PET scan (PET-I) compared to dual-head coincidence gamma camera (CGC-I), included 151 individuals with cancer (Andrieux, 2006). Multidisciplinary sessions were convened to determine theoretical management which included curative or palliative intent and treatment modalities based on the scan results. Clinical follow-up and retrospective analyses were determined to be either "appropriate" or "inappropriate" initially based on PET-I and CGC-I images.  A total of 125 participants were assessable. The investigators determined that theoretical management was significant in 86% of the cases after PET-I, as compared to 70% in the CGC-I group.  The authors concluded that PET-I is superior to CGC-I, and PET-I "remains the standard."

In 2001, the Centers for Medicaid and Medicare Services (CMS) published an analysis of the data regarding oncologic applications of PET scans using gamma cameras which offered the following conclusion:

There are no clear, comparative, broad indication studies, and only very small, indication-specific studies to compare camera-based PET to full-ring PET. Further, these studies are designed to focus mainly on the intrinsic performance of the scanners, not the evaluation of reconstruction and processing algorithms on the sensitivity and specificity of different systems under conditions of actual clinical use. In other words, after an exhaustive search for empirical data, there is no body of evidence that attests to the medical benefit associated with use of camera-based PET that is comparable to the literature used to arrive at the December 15, 2000 decision memorandum for full-ring PET. The extension of that decision memorandum to camera-based systems, while anecdotally supported by nuclear medicine experts, cannot be clearly justified, based on existing clinical and scientific data.

In fact, review of the existing literature on camera-based PET leads to the conclusion, present in several articles, that these systems miss a significant number of small and medium-sized malignant lesions. Because of the limited size of the studies and other methodologic weaknesses, it is not possible to make confident estimates of the frequency with which these different systems produce false positive or false negative results. Furthermore, it is not possible to determine the clinical significance of diagnostic errors that might result from use of these PET technologies. However, given the intended diagnostic role for oncologic uses of PET, it is likely that inaccurate results provided by these imaging systems could lead to errors in treatment, such as early termination of chemotherapy or unnecessary surgical intervention. Without better studies that provide more confident estimates of the sensitivity and specificity from camera-based PET systems, it may not be possible for clinicians to properly interpret the findings from these imaging studies.

Cardiac Applications
There is inadequate data regarding the use of PET scanning with gamma cameras in the evaluation of coronary perfusion defects. The use of this imaging modality to assess myocardial viability has been reported by two studies. Srinivasan and colleagues reported on a case series of 28 subjects with chronic coronary artery disease and left ventricular dysfunction. All subjects underwent PET scanning using a gamma camera, conventional PET, and thallium SPECT studies. Conventional PET served as the gold standard. Hasegawa and colleagues compared PET scanning with a gamma camera and conventional PET scanning, as techniques to evaluate myocardial viability in 25 subjects. Both studies suggested some utility for gamma-camera PET scanning for the narrow indication of assessment of myocardial viability. However, the small sample size in these studies does not allow for definitive conclusions (Hasegawa, 1999; Srinivasan, 1998). Since these studies were published, very little additional published evidence has added to the current thinking about this technology in the clinical practice community.

Neurologic Disorders
PET scans have been widely used in the evaluation of neurological disorders, ranging from epilepsy to dementias. There is inadequate data to compare conventional PET with PET scanning with a gamma camera for neurological disorders.

The Society of Nuclear Medicine (SNM) Procedure Guidelines for FDG-PET Brain Imaging refers to gamma cameras as alternatives to PET scanners with 511 keV collimators imaging single scintillations as "not recommended" and dual-head gamma cameras for coincidence imaging (with no collimators) as having "extremely limited performance characteristics" (Waxman, 2009). A search of additional SNM guidance papers did not locate any further comments on PET imaging with gamma cameras.

Background/Overview

Dedicated PET scanners consist of multiple detectors arranged in a full or partial ring around the individual, permitting the simultaneous detection of high-energy paired photons emitted at 180 degrees from one another. The clinical value of PET scans is related both to the ability to image the relative metabolic activity of target tissues and the resolution associated with PET scanners. Earlier, the requirement of on-site manufacture of the FDG and the expense of the dedicated PET scanner limited the widespread availability of PET scanning. However, radiolabeled FDG has a relatively long half-life of 110 minutes, permitting off-site manufacture at distribution centers with transport to nearby facilities. Researchers have investigated whether the more readily available SPECT cameras, routinely used to detect low-energy photons, could be adapted for use to detect higher energy photons emitted from positrons. An additional technical challenge is the use of sodium iodide crystals, which scintillate in response to bombardment by photons. In SPECT cameras, these crystals have been optimized to detect lower energy photons, used in routine nuclear medicine studies and not the high-energy photons associated with FDG. These technical issues raise questions regarding the diagnostic performance of FDG-SPECT, in comparison to conventional PET scanning. Oncologic and cardiac applications have been the most thoroughly studied.

Definitions

Positron emission tomography (PET): An imaging technique that measures the concentration of chemicals injected into the body, and provides images of the chemical function of body parts of interest.

Scintigraphy: A diagnostic procedure that produces pictures (scans) of radiation sources within structures inside the body, including areas where there are cancer cells. Scintigraphy is used to diagnose, stage, and monitor disease. A small amount of a radioactive chemical (radionuclide) is injected into a vein or swallowed, and different radionuclides travel through the blood to different organs. A machine with a special camera moves over the person lying on a table and detects the type of radiation given off by the radionuclides, forming a computer image of the areas where the radionuclide builds up.

Coding

The following codes for treatments and procedures applicable to this document are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services are Investigational and Not Medically Necessary:
For the procedure code listed below in all instances, or when the code describes a procedure indicated in the Position Statement section as investigational and not medically necessary.

CPT  
78999 Unlisted miscellaneous procedure, diagnostic nuclear medicine [when specified as fluorine-18 fluorodeoxyglucose (F-18 FDG) imaging using dual-head coincidence detection system (non-dedicated PET scan)]
   
HCPCS  
S8085 Fluorine-18 fluorodeoxyglucose (F-18 FDG) imaging using dual-head coincidence detection system (non-dedicated PET scan)
   
ICD-10 Diagnosis  
  All diagnoses
   
References

Peer Reviewed Publications:

  1. Andrieux A, Switsers O, Chajari MH, et al. Clinical impact of fluorine-18 fluorodeoxyglucose positron emission tomography in cancer patients. A comparative study between dedicated camera and dual-head coincidence gamma camera. Q J Nucl Med Mol Imaging. 2006; 50(1):68-77.
  2. Beller GA1, Heede RC. SPECT imaging for detecting coronary artery disease and determining prognosis by noninvasive assessment of myocardial perfusion and myocardial viability. J Cardiovasc Transl Res. 2011; 4(4):416-424.
  3. Eschmann SM, Bitzer M, Paulsen F, et al. The benefit of functional-anatomical imaging with [18F]fluorodeoxyglucose utilizing a dual-head coincidence gamma camera with an integrated X-ray transmission system in non-small cell lung cancer. Nucl Med Commun. 2004; 25(9):909-915.
  4. Even-Sapir E, Metser U, Mishani E, et al. The detection of bone metastases in patients with high-risk prostate cancer: 99mTc-MDP Planar bone scintigraphy, single- and multi-field-of-view SPECT, 18F-fluoride PET, and 18F-fluoride PET/CT. J Nucl Med. 2006; 47(2):287-297.
  5. Goldstein D, Tan BS, Rossleigh M, et al. Gastrointestinal stromal tumors: correlation of F-FDG gamma camera-based coincidence positron emission tomography with CT for the assessment of treatment response – an AGITG Study. Oncology. 2005; 69(4):326-332.
  6. Hasegawa S, Uehara T, Yamaguchi H, et al. Validity of 18F-fluorodeoxyglucose imaging with a dual-head coincidence gamma camera for detection of myocardial viability. J Nucl Med. 1999; 40(11):1884-1892.
  7. Meller J, Koster G, Liersch T, et al. Chronic bacterial osteomyelitis: prospective comparison of 18F-FDG imaging with a dual-head coincidence camera and 111In-labeled autologous leukocyte scintigraphy. Eur J Nucl Med Mol Imaging. 2002; 29(1):53-60.
  8. Srinivasan G, Kitsiou AN, Bachrach SL, et al. [18F] fluorodeoxyglucose single photon emission computed tomography: can it replace PET and thallium SPECT for the assessment of myocardial viability? Circulation. 1998; 97(9):843-850.
  9. Wintermark M, Sesay M, Barbier E, et al. Comparative overview of brain perfusion imaging techniques. J Neuroradiol. 2005; 32(5):294-314. 

Government Agency, Medical Society, and Other Authoritative Publications:

  1. American College of Radiology (ACR). Diagnostic Radiology: Nuclear Medicine Practice Parameters and Technical Standards. Available at: https://www.acr.org/Quality-Safety/Standards-Guidelines/Practice-Guidelines-by-Modality/Nuclear-Medicine . Accessed on March 17, 2017.
  2. Centers for Medicare and Medicaid Services. National Coverage Determination for PET Scans. NCD #220.6. Effective March 7, 2013. Available at: http://www.cms.gov/medicare-coverage-database/details/ncd-details.aspx?NCDId=211&ncdver=5&NCAId=92&ver=19&NcaName=Positron+Emission+Tomography+&bc=BEAAAAAAIEAAAA%3d%3d&. Accessed on March 17, 2017.
  3. Centers for Medicare and Medicaid Services. National Coverage Determination for Single Photon Emission Computed Tomography (SPECT). NCD #220.12. Effective October 1, 2002. Available at: http://www.cms.gov/medicare-coverage-database/details/ncd-details.aspx?&NCDId=271&ncdver=1&NCDSect=220.12&bc=BEAAAAAAIEAAAA==&. Accessed on March 17, 2017.
  4. Patel MR, Picard M, Shaw LJ, et al. 2013 ACCF/ACR/ASE/ASNC/SCCT/SCMR Appropriate Utilization of Cardiovascular Imaging in Heart Failure. A Joint Report of the American College of Radiology Appropriateness Criteria® Committee and the American College of Cardiology Foundation Appropriate Use Criteria Task Force.
  5. Waxman AD, Herholz K, Lewis DH, et al. Society of Nuclear Medicine (SNM) Procedure Guideline for FDG PET Brain Imaging. 2009; Version 1.0. Available at:  http://interactive.snm.org/docs/Society%20of%20Nuclear%20Medicine%20Procedure%20Guideline%20for%20FDG%20PET%20Brain%20Imaging.pdf. Accessed on March 17, 2017.
Index

Camera Based PET Scans
FDG-SPECT
Gamma Cameras, PET Scanning Using
SPECT, Metabolic
PET Scanning Using Gamma Cameras

The use of specific product names is illustrative only.  It is not intended to be a recommendation of one product over another, and is not intended to represent a complete listing of all products available.

Document History

Status

Date

Action

Reviewed 05/04/2017 Medical Policy & Technology Assessment Committee (MPTAC) review.
Reviewed 05/03/2017 Hematology/Oncology Subcommittee review. References were updated.
Reviewed 05/05/2016 MPTAC review.
Reviewed 05/04/2016 Hematology/Oncology Subcommittee review. References were updated. Removed ICD-9 codes from Coding section.
Reviewed 05/07/2015 MPTAC review.
Reviewed 05/06/2015 Hematology/Oncology Subcommittee review. References were updated.
Reviewed 05/15/2014 MPTAC review.
Reviewed 05/14/2014 Hematology/Oncology Subcommittee review. References were updated.
Reviewed 05/09/2013 MPTAC review.
Reviewed 05/08/2013 Hematology/Oncology Subcommittee review. References were updated.
Reviewed 05/10/2012 MPTAC review.
Reviewed 05/09/2012 Hematology/Oncology Subcommittee review. References were updated.
Reviewed 05/19/2011 MPTAC review.
Reviewed 05/18/2011 Hematology/Oncology Subcommittee review. Updated the Rationale, References and Websites.
Reviewed 05/13/2010 MPTAC review. Rationale and References were updated.
Reviewed 05/12/2010 Hematology/Oncology Subcommittee review.
Reviewed 05/21/2009 MPTAC review. Rationale and References were updated.
Reviewed 05/20/2009 Hematology/Oncology Subcommittee review.
Reviewed 05/15/2008 MPTAC review.
  02/21/2008 The phrase "investigational/not medically necessary" was clarified to read "investigational and not medically necessary." This change was approved at the November 29, 2007 MPTAC meeting.
Reviewed 05/17/2007 MPTAC review. References were updated. Coding updated; removed HCPCS G0231, G0232, G0233, G0234 deleted 03/31/2005.
Reviewed 06/08/2006 MPTAC review. Updated literature search performed with no substantive information found. 
Revised 07/14/2005 MPTAC review. Revision based on Pre-merger Anthem and Pre-merger WellPoint Harmonization.
Pre-Merger Organizations & Relevant Harmonization History

Last Review Date

Document Number

Title

 

WellPoint, Inc.

04/28/2005

RAD.00002 Positron Emission Tomography
 

04/28/2005

RAD.00023 Single Photon Emission Computed Tomography (SPECT) and Scintimammography
Anthem, Inc.

07/27/2004

RAD.00002 Positron Emission Tomography
 

04/27/2004

RAD.00023 Single Photon Emission Computed Tomography (SPECT) and Scintimammography
WellPoint Health Networks, Inc.

09/23/2004

4.01.17 Pet Scanning Using Gamma Cameras