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Home , Bone scintigraphy, Scintigraphy

Society of Procedure Guideline for version 3.0, approved June 20, 2003

Authors: Kevin J. Donohoe, MD (Beth Israel Deaconess Medical Center, Boston, MA); Manuel L. Brown, MD (Henry Ford Hospital, Detroit, MI); B. David Collier, MD (Faculty of Medicine, Kuwait University, Kuwait); Robert F. Carretta, MD (Amersham Health, Princeton, NJ); Robert E. Henkin, MD (Loyola University Medical Center, Maywood, IL); Robert E. O’Mara (University of Rochester School of Medicine and Dentistry, Rochester, NY); and Henry D. Royal, MD (Mallinck- rodt Institute of , St. Louis, MO).

I. Purpose III. Common Indications The purpose of this guideline is to assist nuclear A. Neoplastic disease medicine practitioners in recommending, perform- B. ing, interpreting, and reporting the results of bone C. Osteomyelitis scintigraphy. D. Stress reaction/ E. F. Arthritides II. Background Information and Definitions G. Reflex sympathetic dystrophy A. is a diagnostic study used to H. Bone infarcts evaluate the distribution of active bone forma- I. Bone graft viability tion in the body. J. Otherwise unexplained bone pain B. Whole-body bone scintigraphy produces planar K. Distribution of osteoblastic activity before ra- images of the skeleton, including anterior and dionuclide therapy for bone pain posterior views of the axial skeleton. Anterior and/or posterior views of the appendicular IV. Procedure skeleton also are obtained. Additional views are obtained as needed. A. Patient Preparation C. Limited bone scintigraphy records images of 1. The rationale for performing the procedure only a portion of the skeleton. and the details of the procedure itself should D. Bone single-photon emission computed tomog- be explained to the patient in advance. Unless raphy (SPECT) produces a tomographic image of contraindicated, patients should be well hy- a portion of the skeleton. drated and instructed to drink 2 or more 8-oz E. Multiphase bone scintigraphy usually includes glasses of water between the time of injection blood flow images, immediate images, and de- and the time of delayed imaging. The patient layed images. The blood flow images are a dy- should be asked to urinate immediately be- namic sequence of planar images of the area of fore delayed imaging and to drink plenty of greatest interest obtained as the tracer is injected. fluids for at least 24 h after radiopharmaceuti- The immediate (blood pool or soft tissue phase) cal administration. images include 1 or more static planar images of B. Information Pertinent to Performing the Proce- the areas of interest, obtained immediately after dure the flow portion of the study and completed 1 . Question(s) to be answered by bone scintig- within 10 min after injection of the tracer. De- r a p h y layed images may be limited to the areas of in- 2. History of fractures, trauma, osteomyelitis, cel- terest or may include the whole body, may be lulitis, edema, arthritis, , metabolic planar or tomographic, and are usually acquired bone disease, or limitation of function 2–5 h after injection. If necessary, additional de- 3. Current symptoms, physical findings layed images may be obtained up to 24 h after 4. History of recent scintigraphy, especially with tracer injection. 131I, 67Ga, or 111In 206 • BONE SCINTIGRAPHY

5. Results of prior bone scintigraphy of ). 6. Results of prior imaging studies, such as con- E. Image Acquisition ventional radiographs, computed tomogra- 1. Flow images phy, and magnetic resonance imaging If flow images are acquired, the camera 7. History of therapy that might affect the re- should be positioned over the region of inter- sults of bone scintigraphy (e.g., antibiotics, est before tracer injection. The acquisition steroids, chemotherapy, , computer should be programmed to acquire diphosphonates, or iron therapy) approximately 30 frames. When digital im- 8. History of orthopedic (e.g., presence and loca- ages are acquired, blood flow images may be tion of prosthetic implants) and nonorthope- obtained in a 64 × 64 × 16 or greater matrix at dic (e.g., ileal conduit) surgery that might af- 1–3 s/frame. If film is used, 3–5 s/frame may fect the results of bone scintigraphy be used. 9. Relevant laboratory results (e.g., -spe- 2. Blood pool (tissue phase) images cific antigen in patients with ) Blood pool images should be acquired imme- 10. History of anatomic or functional renal abnor- diately after the flow portion of the study and malities completed within 10 min of tracer injection, C. Precautions for approximately 3–5 min/image. After 10 None min, some activity may be apparent in the D. skeleton. Blood pool images are usually ob- Several 99mTc-labeled radiopharmaceuticals (e.g. tained in a 128 × 128 × 16 or greater matrix, diphosphonates) are available for bone scintigra- with count density of approximately 300,000 phy. The usual administered activity for adult counts/image (150,000–200,000 counts/im- patients is 740–1,110 MBq (20–30 mCi) injected age may be adequate for extremities). intravenously. For markedly obese adult pa- 3. Delayed (skeletal phase) images tients, the administered activity may be in- Routine delayed images are usually obtained creased to 11–13 MBq/kg (300–350 µCi/kg). For from 2–5 h after injection. pediatric patients, the administered activity is Whole-body bone scintigraphy can be ac- 9–11 MBq/kg (250–300 µCi/kg), with a mini- complished with multiple overlapping im- mum of 20–40 MBq (.05–1.0 mCi). The maximum ages (i.e., spot imaging) or with continuous administered activity for pediatric patients images (i.e., whole-body scan) obtained in an- should not exceed the administered activity for terior and posterior views with a high-resolu- an adult. tion or ultrahigh-resolution collimator. When Bone radiopharmaceuticals are subject to oxi- spot views are used as the primary method of dation. Care should be taken to avoid introduc- acquiring bone images, the areas of bony ing air into the multidose vial. Quality control skeleton covered by the spot views must over- should be performed before administration of lap to avoid missing regions of the skeleton. the radiopharmaceutical (see the Society of Nu- The first spot view of the axial skeleton, clear Medicine [SNM] Procedure Guideline for Use usually the chest, is acquired for approxi-

Radiation Dosimetry in Adults

Ra d i o p h a r m a c e u t i c a l s Administered Organ Receiving the Effective Activity Largest Radiation Dose* Dose MBq mGy/MBq mSv/MBq (mCi) (rad/mCi) (rem/mCi)

99mTc-phosphates 740Ð1110 Bone 0.0080 and phosphonates (20Ð30) 0.063 (0.030) Intravenously (0.23)

*International Commission on Radiological Protection. Radiation Dose to Patients from Radiopharmaceuticals. ICRP re- port 53. London, UK: ICRP; 1988:215. Values for normal bone uptake and normal renal function. See also Medical Internal Radiation Dose Committee dose estimate report No. 13: radiation absorbed dose for 99mTc-labeled bone imaging agents. J Nucl Med. 1989;30:1117–1122. SOCIETY OF NUCLEAR MEDICINE PROCEDURE GUIDELINES MANUAL AUGUST 2003 • 207

Radiation Dosimetry in Children (5 Years Old)

Ra d i o p h a r m a c e u t i c a l s Administered Organ Receiving the Effective Activity Largest Radiation Dose* Dose MBq/kg mGy/MBq mSv/MBq (mCi/kg) (rad/mCi) (rem/mCi)

99mTc-phosphates 9Ð11 Bone 0.025 and phosphonates (0.20Ð0.30) 0.22 (0.093) Intravenously (0.81) Min: 0.50 mCi Max: 30 mCi

*International Commission on Radiological Protection. Radiation Dose to Patients from Radiopharmaceuticals. ICRP report 53. London, UK: ICRP; 1988:215. Values for normal bone uptake and normal renal function. See also Medical Internal Radiation Dose Committee dose estimate report No. 13: radiation absorbed dose for 99mTc-labeled bone imaging agents. J Nucl Med. 1989;30:1117–1122.

mately 500,000–1 million counts. The remain- 60–120 stops, 64 × 64 × 16 or greater matrix, ing spot views are then acquired for the same and 10–40 s/stop. An equivalent total number time as the first view. Spot images may be ob- of counts should be acquired if continuous ac- tained using a 128 × 128 × 16 or 256 × 256 × 16 quisition is used. matrix. Whole-body views are usually ob- 5. Other imaging tained in a 256 × 1024 × 16 or greater matrix. Additional delayed (6–24-h) images will re- Computer acquisition, processing, and dis- sult in a higher target-to-background ratio play of images are very helpful and particu- and may permit better evaluation of the pelvis larly so in pediatric populations because of if it was obscured by bladder activity on the extreme ranges of normal uptake. Films of routine delayed images. Six- to twenty-four-h scintigrams photographed with different in- delayed imaging may be particularly helpful tensities also may be helpful when digital pro- in patients with renal insufficiency or urinary cessing and review are not available. retention. When whole-body scanning is used, the A pinhole collimator may be used if very count rate (usually of the anterior chest) high-resolution images of a specific area are should be determined before image acquisi- necessary. Approximately 75,000–100,000 tion. The scanning speed should be adjusted counts should be obtained for pinhole colli- so that routine delayed (obtained 2–5 h after mator views. Zoom magnification or a con- injection) anterior or posterior whole-body verging collimator also may be used to im- images contain >1.5 million counts. If the prove resolution, particularly when small scanner electronically joins multiple passes, structures or pediatric patients are being im- care must be taken to avoid having the “zip- aged. The physician interpreting the image per” superimposed on the spine. should be notified when collimators that in- When the probability of disseminated dis- troduce distortion (e.g., a pinhole collimator) ease is small, a limited study is reasonable. are used. When disseminated disease is more likely, Other views (e.g., lateral, oblique, or tan- spot views limited to the area of interest may gential) and special views (e.g., frog-leg views be a source of error if distant disease is pre- of the hips or sitting-on-detector [caudal] sent. views of the pelvis) may be obtained when 4. SPECT imaging necessary. In some patients, SPECT imaging is helpful to F. Interventions better characterize the presence, location, and The pelvis can be difficult to evaluate when extent of disease. SPECT imaging should be there is overlying bladder activity. In patients performed as recommended by the camera with pelvic symptoms, 1 or more of the follow- manufacturer. Typical acquisition and pro- ing additional views may better evaluate the cessing parameters are 360° circular orbit, pelvis. 208 • BONE SCINTIGRAPHY

1. Repeat images immediately after voiding 3. Soft tissues 2. Sitting-on-detector (caudal) or oblique views a. Normal structures should be noted: 3. Lateral views i. Kidneys 4. 24-hr–delayed images ii. Bladder 5. SPECT acquisition. Single or multiple rapid iii. Generalized interstitial uptake com- (5–10 min/acquisition) SPECT acquisition(s) pared with normal bone are preferred to avoid artifacts caused by (a) Increased changing activity in the bladder. Bladder arti- (1) Renal failure facts are exaggerated in the plane in which the (2) Dehydration SPECT acquisition begins and ends. Begin- (3) Shortened interval between in- ning SPECT acquisition with the camera jection and imaging heads in the left and right lateral positions (for (b) Decreased dual-head camera) or posterior position (for (1) Superscan single-head camera) will help reduce bladder- (2) Prolonged interval between in- filling artifact. jection and imaging 6. Image immediately after catheterization of b. Focal tracer uptake the bladder. (Note: Bladder catheterization c. Diffuse tracer uptake should be reserved for patients in whom visu- 4. Bone scans are very sensitive for disease, but alization of the pelvis is essential.) specificity of findings is low and must be in- G. Processing terpreted in of other information Generally no special processing of planar imag- a. History ing is required. For general SPECT image pro- b. Physical exam cessing guidelines, refer to the SNM P r o c e d u r e c. Other test results Guideline for General Imaging. d. Comparison with previous studies H. Interpretation Criteria I. Reporting 1. Increased (decreased) tracer activity in the 1. Description of technique bone compared with normal bone. a. Flow images a. Focal b. Blood pool images b. Diffuse c. Delayed images c. Indicates increased (decreased) osteoblas- d. Injection site tic activity e. SPECT (if applicable) d. Differential diagnosis is long, but can be 2. Description of abnormal tracer uptake narrowed in light of: a. Increased i. Configuration of the abnormality or ab- b. Decreased normalities c. Pattern of abnormal uptake ii. Location and number of abnormalities d. Bone findings e. Focal decrease without adjacent increase in e. Soft tissue findings tracer uptake is: 3. Correlation with other studies i. Less common than focally increased ac- 4. Comparison with previous studies tivity 5. Interpretation ii. Often caused by benign conditions: a. Narrow differential as much as possible (a)Attenuation b. Recommend further, more definitive (b) Artifact study(ies), if differential diagnosis is broad (c) Absence of bone (e.g., surgical resec- J. Quality Control tion) See the SNM Procedure Guideline for General 2. Change in focal abnormalities compared with I m a g i n g. previous study K. Sources of Error a. Decrease in intensity of tracer uptake and 1. Urine contamination or a urinary diversion number of abnormalities: reservoir i. Often indicates improvement 2. Injection artifacts ii. May be secondary to focal therapy (e.g., 3. Prosthetic implants, radiographic contrast radiation therapy) materials, or other attenuating artifacts that b. Increase in intensity of tracer uptake and in might obscure normal structures number of abnormalities may indicate: 4. Homogeneously increased bony activity (e.g., i. Progression of disease “superscan”) ii. Flare response to therapy 5. Patient motion SOCIETY OF NUCLEAR MEDICINE PROCEDURE GUIDELINES MANUAL AUGUST 2003 • 209

6. Greater than necessary collimator-to-patient clear Medicine. New York, NY: Mosby; 1996. distance Cook, GJ, Fogelman I. Skeletal metastases from breast 7. Imaging too soon after injection, before the ra- cancer: imaging with nuclear medicine. Semin Nucl diopharmaceutical has been optimally Med. 1999;29:69–79. cleared from the soft tissues Fogelman I, Collier BD, Brown ML. Bone scintigraphy: 8. Restraint artifacts caused by soft-tissue com- part 3. Bone scanning in metabolic bone disease. J pression Nucl Med. 1993;34:2247–2252. 9. Prior administration of a higher energy ra- Gates, GF. SPECT bone scanning of the spine. Semin dionuclide (131I, 67Ga, 111In) or of a 99mTc ra- Nucl Med. 1998;27:291–305. diopharmaceutical that accumulates in an or- Holder LE. Bone scintigraphy in skeletal trauma. Radiol gan that could obscure or confound the Clin North Am. 1993;31:739–781. skeletal activity Pomeranz SJ, Pretorius HT, Ramsingh PS. Bone scintig- 10. Radioactivity extraneous to the patient raphy and multimodality imaging in bone neopla- 11. Significant findings outside the area of inter- sia: strategies for imaging in the new health care cli- est that may be missed if a limited study is mate. Semin Nucl Med. 1994;24:188–207. performed Ryan, PJ, Fogelman I. Bone scintigraphy in metabolic 12. Radiopharmaceutical degradation bone disease. Semin Nucl Med. 1997;27:291–305. 13. Changing bladder activity during SPECT of pelvic region VII. Disclaimer 14. Purely lytic lesions 15. Pubic lesions obscured by underlying bladder The Society of Nuclear Medicine has written and ap- activity proved guidelines to promote the cost-effective use of 16. Renal failure high-quality nuclear medicine procedures. These generic recommendations cannot be applied to all pa- tients in all practice settings. The guidelines should not V. Issues Requiring Further Clarification be deemed inclusive of all proper procedures or exclu- None sive of other procedures reasonably directed to obtain- ing the same results. The spectrum of patients seen in a specialized practice setting may be quite different from VI. Concise Bibliography the spectrum of patients seen in a more general practice Brown ML, Collier BD, Fogelman I. Bone scintigraphy: setting. The appropriateness of a procedure will de- part 1. Oncology and . J Nucl Med. pend in part on the prevalence of disease in the patient 1993;34:2236–2240. population. In addition, the resources available to care Brown ML, O’Connor MK, Hung JC, et al. Technical as- for patients may vary greatly from one medical facility pects of bone scintigraphy. Radiol Clin North Am. to another. For these reasons, guidelines cannot be 1993;31:721–730. rigidly applied. Collier BD, Fogelman I, Brown ML. Bone scintigraphy: Advances in medicine occur at a rapid rate. The date part 2. Orthopedic bone scanning. J Nucl Med. of a guideline should always be considered in deter- 1993;34:2241–2246. mining its current applicability. Collier BD, Fogelman I, Rosenthall L, eds. Skeletal Nu-