Lindsay BryantLindsay Bryant

Nuclear MedicineNuclear Medicine

Radiopharmaceutical administered to Radiopharmaceutical administered to the patient and subsequently the patient and subsequently recording its distribution in the body recording its distribution in the body over a defined period of time. over a defined period of time.

Used to detect pathologyUsed to detect pathology• Very sensitiveVery sensitive• NonspecificNonspecific

RadiopharmaceuticalsRadiopharmaceuticals

No physiologic response when No physiologic response when administered for diagnostic or therapeutic administered for diagnostic or therapeutic purposes. Selective uptake of these purposes. Selective uptake of these compounds by various organs forms the compounds by various organs forms the basis for nuclear imagingbasis for nuclear imaging

Two components: Two components: • main component - distributedmain component - distributed• radionuclide tagged to this componentradionuclide tagged to this component

Emits gamma rays which permit detection of the Emits gamma rays which permit detection of the compound compound

Components localize by active transport, Components localize by active transport, phagocytosis, etc. phagocytosis, etc.

Physiologic function can be assessed, but Physiologic function can be assessed, but spatial resolution is relatively poorspatial resolution is relatively poor

Common Nuclear ProceduresCommon Nuclear Procedures

1.1. Cardiac studies Cardiac studies 2.2. Skeletal studies Skeletal studies 3.3. Renograms and renal scans Renograms and renal scans 4.4. Ventilation-Perfusion studies Ventilation-Perfusion studies 5.5. PET studies PET studies 6.6. Evaluation of neurodegenerative Evaluation of neurodegenerative

disorders, brain tumor recurrence, disorders, brain tumor recurrence, and myocardial viability. and myocardial viability.

Less Common Nuclear Less Common Nuclear ProceduresProcedures

1.1. Diagnostic thyroid studiesDiagnostic thyroid studies2.2. Hepatobiliary studiesHepatobiliary studies3.3. Brain imaging Brain imaging 4.4. White blood cell studies White blood cell studies 5.5. Gastrointestinal bleeding studies Gastrointestinal bleeding studies 6.6. Lymphoscintigraphy Lymphoscintigraphy 7.7. Parathyroid scans Parathyroid scans

99m99mTc bone scintigraphyTc bone scintigraphy

Effective method for screening the Effective method for screening the whole body for bone metastaseswhole body for bone metastases

99m99mTc methylene diphosphonate Tc methylene diphosphonate (MDP) is the most frequently used (MDP) is the most frequently used isotope. isotope.

99m99mTc planar bone scintiscans help Tc planar bone scintiscans help identify tumors by detecting the identify tumors by detecting the increased osteoblastic activity. increased osteoblastic activity.

Scintigraphy IndicationsScintigraphy Indications

1.1. Staging in asymptomatic patientsStaging in asymptomatic patients2.2. Evaluation of persistent pain (with Evaluation of persistent pain (with

negative radiograph findings)negative radiograph findings)3.3. Determining the extent of bone Determining the extent of bone

metastases ( with positive metastases ( with positive radiograph findings)radiograph findings)

4.4. Differentiating metastatic from Differentiating metastatic from traumatic fractures traumatic fractures

Indications continuedIndications continued

Routinely done as part of initial Routinely done as part of initial staging of LUNG and BREAST cancerstaging of LUNG and BREAST cancer• The risk of presenting with metastatic The risk of presenting with metastatic

brain or bone disease is sufficiently highbrain or bone disease is sufficiently high Not routinely done as part of initial Not routinely done as part of initial

staging of COLON cancerstaging of COLON cancer• The risk is relatively low for metastases The risk is relatively low for metastases

to bone or brain and bone scans are not to bone or brain and bone scans are not done unless symptoms or other findings done unless symptoms or other findings indicate a potential problem. indicate a potential problem.

Scintigraphy Scintigraphy

The classic The classic pattern appears pattern appears as the presence as the presence of multiple of multiple randomly randomly distributed distributed focal lesions focal lesions throughout the throughout the skeletonskeleton

Bone MetastasesBone Metastases

A 99mTc-MDP bone scan in the anterior and posterior projections demonstrates multiple foci of increased radiopharmaceutical accumulation (spine, ribs, pelvis, and left clavicle) with the typical appearance of bone metastases

AdvantagesAdvantages

Low costLow cost Widely availableWidely available Useful in imaging entire skeletonUseful in imaging entire skeleton SensitiveSensitive

• 90% for FDG-PET (18- 90% for FDG-PET (18- fluorodeoxyglucose )fluorodeoxyglucose )

• 82% for whole-body MRI82% for whole-body MRI• 71% for 71% for 99m99mTc bone scintiscanningTc bone scintiscanning

Continues to be used as initial Continues to be used as initial screening investigation screening investigation

DisadvantagesDisadvantages

FiFindings are nonspecific in ndings are nonspecific in determining the cause of increased determining the cause of increased uptake, particularly in solitary uptake, particularly in solitary lesions. lesions.

Poor spatial and contrast resolution. Poor spatial and contrast resolution. Further imaging is required to Further imaging is required to

characterize regions of disseminated characterize regions of disseminated abnormality. abnormality. • CT or MRI is required to localize an area CT or MRI is required to localize an area

of increased glucose metabolismof increased glucose metabolism

False Positives of of False Positives of of 99m99mTc bone Tc bone scintiscans scintiscans

Sensitivities are reportedly 62-89%. Sensitivities are reportedly 62-89%. Many benign processes and normal Many benign processes and normal

variants can produce an area of variants can produce an area of increased isotope uptake that increased isotope uptake that mimics a metastatic deposit.mimics a metastatic deposit.

Solitary areas of abnormal uptake Solitary areas of abnormal uptake benign processes occur in benign processes occur in approximately one third of patients approximately one third of patients with malignant disease. with malignant disease.

Differential Diagnosis of multiple Differential Diagnosis of multiple scintigraphic abnormalities scintigraphic abnormalities

• Metabolic problems (eg, Cushing Metabolic problems (eg, Cushing syndrome) syndrome)

• Osteomalacia Osteomalacia • TraumaTrauma• ArthritisArthritis• OsteomyelitisOsteomyelitis• Paget disease Paget disease • InfarctionsInfarctions

False Negatives of False Negatives of 99m99mTc bone Tc bone scintiscans scintiscans

Some metastases may produce Some metastases may produce normal scintiscan findings.normal scintiscan findings.

Cold or photopenic metastases may Cold or photopenic metastases may be found in association with lesions be found in association with lesions of highly aggressive anaplastic of highly aggressive anaplastic carcinomascarcinomas

SUMMARYSUMMARY

Nuclear Imaging has an important Nuclear Imaging has an important role in the detection, diagnosis, role in the detection, diagnosis, prognostication, treatment planning, prognostication, treatment planning, and follow-up monitoring of bone and follow-up monitoring of bone metastases. Further imaging or metastases. Further imaging or imaging-guided techniques may be imaging-guided techniques may be required to confirm the diagnosis, to required to confirm the diagnosis, to establish the extent of the disease, establish the extent of the disease, and to find the primary tumor.and to find the primary tumor.

ReferencesReferences

Thomas, MB, Hoff, PM, Wolffe, RA. Thomas, MB, Hoff, PM, Wolffe, RA. Gastrointestinal Carcinomas in: Gastrointestinal Carcinomas in: The The MD Anderson Manual of Medical MD Anderson Manual of Medical OncologyOncology. McGraw-Hill Companies. . McGraw-Hill Companies. 20062006

Wilfred, CG. Wilfred, CG. Bone MetastasesBone Metastases. . www.emedicine.com www.emedicine.com