Nuclear Medicine Imaging Techniques
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Questions and Answers

What is the primary purpose of calibration in CT imaging systems?

  • To evaluate the accuracy of Hounsfield units within 5 units (correct)
  • To perform quality checks on patient imaging
  • To adjust system configurations based on user preference
  • To ensure uniform response throughout the field of view

    • Which component is NOT typically included in the quality control of a combined SPECT/CT system?

  • Daily sensitivity monitoring (correct)
  • Calibration checks for accuracy
  • Attenuation correction accuracy
  • Registration for spatial alignment

    • Which radionuclide parent-daughter system is mentioned in the context of PET/CT generators?

  • Iodine-131 / Xenon-133
  • Technetium-99m / Molybdenum-99
  • Gallium-67 / Gallium-68
  • Strontium-82 / Rubidium-82 (correct)

    • What quality control test is recommended to be performed annually for PET imaging?

    <p>Transverse resolution</p> Signup and view all the answers

    In the context of PET/CT imaging quality control, what aspect needs to be ensured regarding the CT portion?

    <p>It includes additional registration and attenuation correction accuracy tests</p> Signup and view all the answers

    Which collimator type is recommended for planar imaging with 201Tl?

    <p>Low-energy, medium-resolution collimator</p> Signup and view all the answers

    What is the standard energy window percentage when using 99mTc?

    <p>20%</p> Signup and view all the answers

    In SPECT imaging, what is the preferred detector separation for a 180° orbit?

    <p>90°</p> Signup and view all the answers

    Which is NOT a commonly used crystal type in PET cameras?

    <p>Gadolinium Calcium Silicate (GCS)</p> Signup and view all the answers

    What effect does adding additional detectors in SPECT imaging have on acquired counts?

    <p>Doubles acquired counts</p> Signup and view all the answers

    What is the benefit of using an elliptical orbit in SPECT imaging?

    <p>Improves spatial resolution</p> Signup and view all the answers

    Which type of attenuation correction do PET scanners rely on primarily?

    <p>Computed tomography (CT)</p> Signup and view all the answers

    What is a critical factor in determining the suitability of a collimator in nuclear cardiology?

    <p>The energy range of the radiopharmaceutical</p> Signup and view all the answers

    Which of the following stress testing protocols is considered most effective for myocardial perfusion imaging?

    <p>Dipyridamole infusion with immediate imaging</p> Signup and view all the answers

    What image processing method is commonly used in nuclear cardiology for enhancing image quality?

    <p>Convolution Filtering</p> Signup and view all the answers

    In nuclear cardiology, which gating technique is primarily used to synchronize imaging with the cardiac cycle?

    <p>Phase Analysis Gating</p> Signup and view all the answers

    In calculating ejection fraction using gated SPECT imaging, which phase of the cardiac cycle is most critical?

    <p>End-diastolic phase</p> Signup and view all the answers

    Which type of collimator is typically recommended for high-resolution planar imaging in nuclear cardiology?

    <p>Parallel-hole collimator</p> Signup and view all the answers

    What is the primary objective of using a stress testing protocol in nuclear cardiology?

    <p>To provoke ischemia for diagnosis</p> Signup and view all the answers

    What specific attribute does pixel spacing influence in SPECT myocardial perfusion imaging?

    <p>Resolution of the final image</p> Signup and view all the answers

    Which of the following factors is NOT considered when performing quality assurance for imaging equipment in nuclear cardiology?

    <p>Evaluating patient compliance during imaging</p> Signup and view all the answers

    Which of the following radiopharmaceuticals is primarily used in MIBG imaging?

    <p>Iodine-123</p> Signup and view all the answers

    Which of the following practices is recommended to reduce scatter counts during dose calibration for 123I-MIBG?

    <p>Using a commercial copper sleeve or tube</p> Signup and view all the answers

    What specific characteristic of the dose calibrator is crucial for accurate measurement of 123I-MIBG?

    <p>A specific setting for 123I and a correction factor</p> Signup and view all the answers

    In the context of myocardial perfusion imaging, which imaging acquisition method is typically employed to ensure adequate counting statistics?

    <p>10-minute anterior acquisition in a 128 x 128 x 16 matrix</p> Signup and view all the answers

    Which condition should be monitored when administering 123I-MIBG to ensure patient safety and efficacy?

    <p>Potential interactions with prescribed thyroid medications</p> Signup and view all the answers

    Which technique is crucial when setting up imaging sequences before the day of administering 123I-MIBG to enhance the precision of acquired images?

    <p>Testing and configuring the imaging sequence in advance</p> Signup and view all the answers

    What is the correct storage temperature range for 123I-MIBG after calibration?

    <p>68°F to 77°F</p> Signup and view all the answers

    Which of the following is an essential component of the aseptic technique during 123I-MIBG injection?

    <p>Flushing the intravenous line with saline</p> Signup and view all the answers

    How does kidney disease potentially impact the administration of 123I-MIBG?

    <p>It can cause increased radiation exposure to healthy tissues.</p> Signup and view all the answers

    Which factor is crucial to verify before injecting 123I-MIBG into a patient?

    <p>The timing of the calibration</p> Signup and view all the answers

    What procedure should be followed for radiation safety regarding the 123I-MIBG dose after its calibration time?

    <p>It should be discarded after 36 hours.</p> Signup and view all the answers

    What is the recommended method to draw 123I-MIBG for administration to the patient?

    <p>Employing a shielded syringe and aseptic technique.</p> Signup and view all the answers

    What potential risk is associated with administering 123I-MIBG to patients with a history of thyroid cancer?

    <p>Risk of metastasis to other areas due to iodine.</p> Signup and view all the answers

    What is a primary consideration when administering 123I-MIBG to patients with renal insufficiency?

    <p>Potential for impaired clearance of the drug</p> Signup and view all the answers

    Which practice is recommended to mitigate thyroid cancer risk during 123I-MIBG administration?

    <p>Pretreatment with potassium iodide</p> Signup and view all the answers

    What specific action should be taken to ensure patient safety during the administration of 123I-MIBG?

    <p>Ensure the patient is well informed about the procedure</p> Signup and view all the answers

    How is radiation dosimetry relevant in the context of 123I-MIBG testing?

    <p>It informs about the radiation dose received by the patient</p> Signup and view all the answers

    What timing is critical for the acquisition of images after the administration of 123I-MIBG?

    <p>15 minutes after injection for early imaging</p> Signup and view all the answers

    Which patients may be considered for potassium iodide pretreatment before 123I-MIBG administration?

    <p>Patients at increased risk for thyroid cancer</p> Signup and view all the answers

    Why is hydration important before the 123I-MIBG test, especially for certain patients?

    <p>To prevent dehydration-related complications in those with heart failure</p> Signup and view all the answers

    What should be monitored in patients during and after the administration of 123I-MIBG?

    <p>Presence of adverse reactions to the medication</p> Signup and view all the answers

    What is the consequence of not ensuring the camera is unoccupied before administering 123I-MIBG?

    <p>Exposure of the staff to unnecessary radiation</p> Signup and view all the answers

    What timing interval follows the late imaging session after 123I-MIBG injection?

    <p>3 hours and 50 minutes post-injection</p> Signup and view all the answers

    What imaging characteristic distinguishes 99mTc-HMDP and 99mTc-DPD from 99mTc-pyrophosphate?

    <p>They demonstrate soft-tissue uptake.</p> Signup and view all the answers

    Which imaging method is best for calculating the heart-to-contralateral-lung ratio?

    <p>SPECT imaging with a focus on the ribcage.</p> Signup and view all the answers

    What positioning should patients maintain during imaging to visualize the entire ribcage?

    <p>Supine with arms overhead.</p> Signup and view all the answers

    What is a notable feature of the imaging parameters used in different camera systems?

    <p>Variability exists, but general recommendations can guide most systems.</p> Signup and view all the answers

    In the context of 99mTc imaging, which of the following aspects should not be a concern for patient preparation?

    <p>Collecting serum and urine samples prior to imaging.</p> Signup and view all the answers

    What is the primary reason for using 99mTc-pyrophosphate in the United States instead of other radiopharmaceuticals?

    <p>Other alternatives are not FDA approved.</p> Signup and view all the answers

    Which imaging technique is typically used to obtain images of a patient's chest after administering 99mTc-pyrophosphate?

    <p>Planar and SPECT imaging</p> Signup and view all the answers

    What is the typical dose range for administering 99mTc-pyrophosphate intravenously?

    <p>370–740 MBq</p> Signup and view all the answers

    What is the approximate radiation exposure from a 555-MBq dose of 99mTc-pyrophosphate?

    <p>3 mSv</p> Signup and view all the answers

    Why is 99mTc-methylene diphosphonate not recommended for cardiac amyloid imaging?

    <p>It has significantly lower sensitivity.</p> Signup and view all the answers

    What imaging configuration is typically utilized when obtaining images after the administration of 99mTc-pyrophosphate?

    <p>Standard dual-head g-camera with 90° configuration</p> Signup and view all the answers

    What process occurs three hours after the intravenous injection of 99mTc-pyrophosphate?

    <p>Imaging of the chest</p> Signup and view all the answers

    Which condition can 99mTc-pyrophosphate imaging help differentiate in patients with a family history of amyloidosis?

    <p>Variant cardiac ATTR</p> Signup and view all the answers

    What is an essential indication for 99mTc-pyrophosphate imaging in cardiac amyloidosis?

    <p>Patients with negative serum and urine studies for AL</p> Signup and view all the answers

    Which of the following radiopharmaceuticals is associated with nuclear medicine imaging for cardiac amyloidosis?

    <p>99mTc-pyrophosphate</p> Signup and view all the answers

    What is a contraindication for cardiac MRI that makes patients candidates for 99mTc-pyrophosphate imaging?

    <p>Presence of an implantable device</p> Signup and view all the answers

    Which of the following patient preparation protocols is necessary before undergoing 99mTc-pyrophosphate imaging?

    <p>No specific restrictions on diet or medications</p> Signup and view all the answers

    What is the primary utility of the serum free light-chain ratio in the diagnostic process?

    <p>To rule out cardiac ATTR</p> Signup and view all the answers

    What aspect of the 99mTc-pyrophosphate imaging process presents no specific contraindications?

    <p>General nuclear medicine procedure cautions</p> Signup and view all the answers

    In terms of imaging results, what indicates strong myocardial uptake in 99mTc-pyrophosphate scans?

    <p>Diffuse myocardial uptake</p> Signup and view all the answers

    Which imaging technique is considered diagnostic of ATTR cardiomyopathy upon meeting specific criteria?

    <p>99mTc-pyrophosphate imaging with negative serum and urine studies for AL</p> Signup and view all the answers

    What types of examinations can 99mTc-pyrophosphate imaging replace for patients with specific contraindications?

    <p>Cardiac MRIs</p> Signup and view all the answers

    What is the radiopharmaceutical used for adrenal imaging that is taken up by chromaffin cells?

    <p>Metaiodobenzylguanidine (MIBG)</p> Signup and view all the answers

    What is the main challenge in differentiating metastatic adrenal masses from benign lesions using PET/CT?

    <p>False negatives due to small lesions</p> Signup and view all the answers

    What is the standardized uptake value (SUV) threshold indicating positive adrenal uptake?

    <p>Greater than or equal to 3.1</p> Signup and view all the answers

    In imaging suspected pheochromocytomas, what is the sensitivity and specificity of MIBG?

    <p>90% sensitivity, 90% specificity</p> Signup and view all the answers

    What is a notable characteristic of the uptake pattern of radioiodinated MIBG in normal tissues?

    <p>Faint activity in the heart and thyroid gland</p> Signup and view all the answers

    What percentage of adrenal adenomas are classified as hypermetabolic?

    <p>5%</p> Signup and view all the answers

    What is the typical method of excretion for MIBG after administration?

    <p>Mostly excreted unchanged by the kidneys</p> Signup and view all the answers

    What is generally observed in patients with nonprimary adrenal malignancies regarding adrenal masses?

    <p>Up to 50% may be benign</p> Signup and view all the answers

    What is the primary rationale for using a specific radiopharmaceutical labeled with iodine-123 in MIBG imaging?

    <p>High radioactivity and short half-life</p> Signup and view all the answers

    Which other neuroendocrine tumors may be localized to a lesser degree by MIBG apart from pheochromocytoma?

    <p>Medullary thyroid carcinoma</p> Signup and view all the answers

    What percentage of patients may visualize the normal adrenal medulla on delayed images?

    <p>30% to 50%</p> Signup and view all the answers

    Pheochromocytomas are often referred to as 'ten-percent tumors' for several reasons. Which of the following is NOT one of those reasons?

    <p>Approximately 10% are ectopic.</p> Signup and view all the answers

    What is the primary imaging method of choice for detecting pheochromocytomas?

    <p>Whole-body imaging with SPECT or SPECT/CT with 123I-MIBG</p> Signup and view all the answers

    Which substance may interfere with the localization of radioiodinated MIBG and should be withheld before imaging?

    <p>Antidepressants</p> Signup and view all the answers

    What is the sensitivity of MIBG in detecting adrenal neuroblastoma and its metastases in affected neonates and children?

    <p>More than 90%</p> Signup and view all the answers

    Which form of imaging is often utilized to visualize skeletal and marrow metastases associated with neuroblastomas?

    <p>Whole-body imaging at 24 and 48 hours post-injection</p> Signup and view all the answers

    What potential effect does aggressive chemotherapy have on imaging for metastases in neuroblastoma?

    <p>Reduces radiopharmaceutical uptake</p> Signup and view all the answers

    Which type of neuroendocrine tumors may result in excessive catecholamine production without secretion into circulation?

    <p>Paragangliomas</p> Signup and view all the answers

    How is the adrenal medullary tissue typically characterized in size compared to the adrenal cortex?

    <p>Small and relatively less extensive</p> Signup and view all the answers

    What imaging technique is particularly sensitive in detecting ectopic lesions in pheochromocytomas?

    <p>Whole-body planar imaging</p> Signup and view all the answers

    What is the primary advantage of using 123I-MIBG over 131I-MIBG in clinical settings?

    <p>Commercial availability makes it easier to obtain</p> Signup and view all the answers

    Which of the following conditions is least likely to influence the administration of 123I-MIBG?

    <p>Patient's weight and height measurements</p> Signup and view all the answers

    Which imaging method is most suitable for distinguishing between neuroendocrine tumors during diagnostic evaluations?

    <p>Iodine-123–metaiodobenzylguanidine (MIBG)</p> Signup and view all the answers

    In preparing a patient for an MIBG scan, which of the following is a mandatory intervention?

    <p>Initiation of potassium iodide or Lugol solution</p> Signup and view all the answers

    What is the key reason MIBG is incorporated into presynaptic adrenergic storage granules?

    <p>Its chemical structure is similar to norepinephrine.</p> Signup and view all the answers

    Which imaging parameter is pivotal when acquiring static images for MIBG?

    <p>Acquiring pelvic images before bladder filling</p> Signup and view all the answers

    What is a common misconception about the pharmacological effects of MIBG?

    <p>It has little or no pharmacological effect.</p> Signup and view all the answers

    For what purpose is SPECT imaging primarily used in conjunction with MIBG?

    <p>To provide clarification of whole-body and static images</p> Signup and view all the answers

    What is the expected imaging speed during a whole-body MIBG scan?

    <p>5 cm/s</p> Signup and view all the answers

    What is the main limitation of using 131I-MIBG compared to its counterpart?

    <p>Its gamma emission is of higher energy and less manageable.</p> Signup and view all the answers

    What is the purpose of 99mTc sestamibi in breast tumor imaging?

    <p>Imaging without uptake in normal breast tissue</p> Signup and view all the answers

    Which of the following is NOT true regarding the characteristics of 111In pentetreotide?

    <p>It interacts poorly with human antibodies</p> Signup and view all the answers

    Which statement about HAMA response is accurate?

    <p>It is linked to the immunogenicity of mouse-derived monoclonal antibodies</p> Signup and view all the answers

    Regarding the use of 67Ga citrate, what is the optimal scanning time for accurate neoplasm imaging?

    <p>24 hours after administration</p> Signup and view all the answers

    What is a key advantage of using 201Tl chloride compared to 67Ga citrate?

    <p>Lower sensitivity to inflammatory conditions</p> Signup and view all the answers

    How should 99mTc sestamibi be administered when used for breast tumor imaging? Select all

    <p>(c ) Via intravenous injection in the arm contralateral to involved breast</p> Signup and view all the answers

    Lymphoscintigraphy is used to:

    <p>All of the above</p> Signup and view all the answers

    111In pentetreotide is a:

    <p>Somatostatin analog</p> Signup and view all the answers

    A HAMA response occurs because:

    <p>Monoclonal antibodies are produced from mouse cells which the human body recognizes as a foreign protein.</p> Signup and view all the answers

    Advantages of 201Tl chloride over 67Ga citrate include:

    <p>All of the above.</p> Signup and view all the answers

    It is possible to use 99mTc sestamibi for breast tumor imaging because there is no uptake of sestamibi in the normal breast.

    <p>False</p> Signup and view all the answers

    A monoclonal antibody is developed which displays cross- reaction. This means:

    <p>The antibody will bind antigens other than the one it was formed with.</p> Signup and view all the answers

    Examples of neuroendocrine tumor include:

    <p>All of the above</p> Signup and view all the answers

    Visualization of kidneys at 48 h is _____on a scan using 111In pentetreotide and _____on a 67Ga citrate scan.

    <p>Normal, abnormal</p> Signup and view all the answers

    18FDG can be used to image tumors because the glycolyticrate is higher in tumor than in normal tissues.

    <p>True</p> Signup and view all the answers

    Which of the following are true regarding 18FDG tumor imaging?

    <p>PET scanning is required.</p> Signup and view all the answers

    Pheochromocytomas are imaged using:

    <p>131I MIBG</p> Signup and view all the answers

    The use of PET imaging in oncology takes advantage of the _____differences between normal and neoplastic tissue.

    <p>Metabolic</p> Signup and view all the answers

    Hodgkin’s disease is a type of:

    <p>Lymphoma</p> Signup and view all the answers

    F-18 fluciclovine is currently an FDA-approved imaging agent for what type of cancer?

    <p>Prostate Cancer</p> Signup and view all the answers

    Recommended dose for imaging with Ga-68 dotatate?

    <p>0.054 mCi/kg up to 5.4 mCi</p> Signup and view all the answers

    Gallium-68 is:

    <p>Generator Produced</p> Signup and view all the answers

    Gallium-68 dotatate is indicated for imaging what type of can- cers utilizing PET?

    <p>Neuroendocrine Tumors</p> Signup and view all the answers

    Recommended dose for imaging with F-18 fluciclovine?

    <p>10 mCi</p> Signup and view all the answers

    Thyrotropin is also known as:

    <p>TSH</p> Signup and view all the answers

    Most people have four parathyroid glands.

    <p>True</p> Signup and view all the answers

    The salivary glands include:

    <p>Sublingual salivary glands</p> Signup and view all the answers

    Which of the following are used to image the parathyroid?

    <p>Tc99 Sestamibi</p> Signup and view all the answers

    Which organ has the highest radiation dosimetry from 67Ga-Citrate when administered in a dose of 5 mCi?

    <p>Bone marrow</p> Signup and view all the answers

    What is the primary method for labeling white blood cells in the context of preparing for imaging?

    <p>Using 99mTc-HMPAO</p> Signup and view all the answers

    In radiation dosimetry for 67Ga-Citrate, which organ has the lowest dosimetry value listed?

    <p>Stomach</p> Signup and view all the answers

    Which step is recommended immediately after labeling blood for imaging procedures?

    <p>Correctly identify the patient before reinjection</p> Signup and view all the answers

    Which imaging protocol may follow the initial whole-body image protocol?

    <p>SPECT or SPECT/CT of the selected area</p> Signup and view all the answers

    What is a primary concern when patients are prepared for imaging after receiving 67Ga-Citrate?

    <p>Removing metallic objects to prevent artifacts</p> Signup and view all the answers

    When assessing radiation dosimetry, which organ is likely to have dosimetry values closer to those of the liver?

    <p>Spleen</p> Signup and view all the answers

    What is the typical half-life of In-111?

    <p>67.4 hours</p> Signup and view all the answers

    Which organ receives the highest dose from 111In-labeled white blood cells?

    <p>Spleen</p> Signup and view all the answers

    What is the recommended adult administered dose of 99mTc-Exametazime?

    <p>7 to 25 mCi</p> Signup and view all the answers

    Which imaging technique is suggested to enhance low count rates during delayed imaging?

    <p>Low-energy, all-purpose collimator</p> Signup and view all the answers

    What is a key benefit of using SPECT or SPECT/CT imaging in diagnostic procedures?

    <p>Enhanced imaging resolution</p> Signup and view all the answers

    What is the energy peak (keV) for the principal radiation of In-111?

    <p>171 keV</p> Signup and view all the answers

    Which parameter does the timing of image acquisition post-dose administration primarily influence?

    <p>Image clarity and detail</p> Signup and view all the answers

    Why is the use of additional static images beneficial in imaging protocols?

    <p>They enhance diagnostic interpretation of images.</p> Signup and view all the answers

    How should the acquired images be processed in SPECT or SPECT/CT imaging?

    <p>Following institution-specific protocol</p> Signup and view all the answers

    What is the average adult dose of 99mTc-sestamibi used for parathyroid imaging?

    <p>20 mCi (740 MBq)</p> Signup and view all the answers

    Which radionuclide is used for imaging recurrent or metastatic colorectal cancer?

    <p>Technetium-99m</p> Signup and view all the answers

    What is the effective dose of 185 MBq of 99mTc-exametazime administered to adults?

    <p>0.15 mSv/MBq</p> Signup and view all the answers

    How long after the injection of Indium-111-capromab pendetide should imaging be ideally performed?

    <p>96 to 120 hours</p> Signup and view all the answers

    Which is the primary organ receiving the largest radiation dose from 99mTc-exametazime in adults?

    <p>Spleen</p> Signup and view all the answers

    For what purpose is 99mTc-exametazime primarily used in imaging?

    <p>Leukocyte labeling in infection imaging</p> Signup and view all the answers

    What is the effective dose in mSv for 3.7 MBq of 99mTc-exametazime administered to children?

    <p>0.054</p> Signup and view all the answers

    What phase begins 15 to 20 minutes after the injection of 99mTc-sestamibi during a parathyroid flow study?

    <p>Thyroid phase</p> Signup and view all the answers

    What is the lowest administered activity of 99mTc-exametazime for children (5 years old) in MBq?

    <p>0.1 MBq</p> Signup and view all the answers

    What should be considered for a patient who is pregnant before proceeding with a breast examination?

    <p>Radiation safety recommendations must be issued.</p> Signup and view all the answers

    What is the recommended delay for breast scintigraphy after a core biopsy?

    <p>4–6 weeks</p> Signup and view all the answers

    Why should the arms of the patient be raised during breast imaging?

    <p>To expose the axilla and minimize normal activity interference.</p> Signup and view all the answers

    What is the purpose of compressing the contralateral breast against the table during the examination?

    <p>To prevent cross-talk of activity.</p> Signup and view all the answers

    What specific assessment should the nuclear medicine physician be aware of prior to the examination?

    <p>Physical signs and symptoms related to previous therapies.</p> Signup and view all the answers

    What should be considered the primary reason for reviewing prior mammograms before performing a new diagnostic procedure?

    <p>To assess changes in breast tissue over time.</p> Signup and view all the answers

    What is a significant caution noted regarding the use of the guidelines for breast cancer evaluation?

    <p>They may not account for individual patient circumstances.</p> Signup and view all the answers

    What element is essential for ensuring effective and safe medical care according to the guidelines?

    <p>Making reasonable judgments based on current knowledge and resources.</p> Signup and view all the answers

    How do the guidelines intend to balance cost-effectiveness and the quality of nuclear medicine procedures?

    <p>By providing a framework that can be adapted based on resources.</p> Signup and view all the answers

    In which circumstance might a practitioner choose to deviate from the established guidelines?

    <p>When resources are limited or conditions have changed.</p> Signup and view all the answers

    What is the recommended patient position to assess feasibility before the breast scintigraphy procedure?

    <p>Prone with arms extended</p> Signup and view all the answers

    What is NOT required for patient preparation prior to undergoing breast scintigraphy?

    <p>Wearing protective lead shielding</p> Signup and view all the answers

    What is the main purpose of the 99mTc-sestamibi breast scintigraphy?

    <p>To assist in determining the effectiveness of chemotherapy for breast carcinoma</p> Signup and view all the answers

    Which imaging techniques are included in the breast scintigraphy procedure using 99mTc-sestamibi?

    <p>Planar imaging and SPECT</p> Signup and view all the answers

    Which professional is mentioned as one of the authors contributing to the guideline on breast scintigraphy?

    <p>Christophe Van de Wiele</p> Signup and view all the answers

    What is the main goal of the guidelines provided by the EANM and SNMMI in the context of breast cancer?

    <p>To optimize the use of nuclear medicine procedures</p> Signup and view all the answers

    Which factors do the guidelines emphasize about the resources available for patient care?

    <p>They vary across different facilities</p> Signup and view all the answers

    What should not be inferred from the guidelines regarding nuclear medicine modalities?

    <p>They are comprehensive of all possible techniques</p> Signup and view all the answers

    What is indicated as an important component of the procedures for sentinel lymph node detection?

    <p>Cross-specialty collaboration</p> Signup and view all the answers

    Which statement reflects a misconception about the guidelines for lymphoscintigraphy and sentinel node localization?

    <p>The guidelines promote the exclusion of other modalities</p> Signup and view all the answers

    Which of the following substances has the highest general injected dose range for surgical applications?

    <p>Antimony trisulphide</p> Signup and view all the answers

    What is the preferred volume range for injections to avoid interference with normal lymphatic flow?

    <p>0.05–0.5 mL</p> Signup and view all the answers

    What is a common practice after injection to improve tracer drainage?

    <p>Gentle massaging of the injection site</p> Signup and view all the answers

    Which radiolabelled colloid has the largest activity range for usage?

    <p>Nanocolloidal albumin</p> Signup and view all the answers

    When is a total injected dose of up to 150 MBq generally considered sufficient?

    <p>For injections done the afternoon prior to surgery</p> Signup and view all the answers

    What is a major concern when performing superficial injections for sentinel lymph node detection?

    <p>They may not accurately identify all relevant nodes.</p> Signup and view all the answers

    What is the benefit of adding pH-balanced 1% lidocaine to radiopharmaceuticals during injection?

    <p>It improves patient comfort without affecting SLN identification.</p> Signup and view all the answers

    Which injection technique reportedly results in higher pain levels for the patient?

    <p>Subareolar injections</p> Signup and view all the answers

    Which imaging method is suggested to potentially improve the identification of sentinel lymph nodes prior to surgery?

    <p>Ultrasound guidance for placement of injections</p> Signup and view all the answers

    What should be a routine practice concerning the imaging systems used in sentinel lymph node procedures?

    <p>Quality control should be routinely performed.</p> Signup and view all the answers

    What is the primary purpose of performing whole-body scans following the administration of sodium iodide?

    <p>To detect areas of radioiodine concentration</p> Signup and view all the answers

    What scanning method is utilized to capture images after the administration of sodium iodide?

    <p>Rectilinear scanning</p> Signup and view all the answers

    How long after administration is it typical to perform whole-body scans with sodium iodide?

    <p>48 to 72 hours</p> Signup and view all the answers

    Which component is excluded from the imaging process during whole-body scans?

    <p>Lower distal extremities</p> Signup and view all the answers

    What is typically requested of a patient after the scan images are captured?

    <p>Remain until images are reviewed</p> Signup and view all the answers

    What is the total elapsed time for the whole-body scan procedure described?

    <p>40 minutes</p> Signup and view all the answers

    Which feature of the scanner allows for the detection of all areas of radioiodine concentration?

    <p>Lack of background erase and contrast enhancement</p> Signup and view all the answers

    What is one primary reason for performing whole-body metastatic surveys in patients with thyroid cancer?

    <p>To minimize patient scheduling disruptions</p> Signup and view all the answers

    Why is it important to assume little or no accumulation of radioiodine by remaining thyroid tissue?

    <p>To ensure that radioiodine therapy is effective</p> Signup and view all the answers

    What is one benefit of using a dual-probe rectilinear scanner for metastatic surveys?

    <p>It helps achieve lower body background levels</p> Signup and view all the answers

    Following surgery for thyroid carcinoma, why should radioiodine therapy be delayed?

    <p>To ensure a large tumor specimen is available for pathology</p> Signup and view all the answers

    What monitoring aspect is crucial when evaluating the effectiveness of radioiodine therapy?

    <p>The success in reducing radioactive iodine uptake by the thyroid</p> Signup and view all the answers

    What is expected regarding the excretion of 1-131 in relation to thyroid tissue activity?

    <p>Little to no excretion suggests less functional tissue</p> Signup and view all the answers

    What does the dual-probe rectilinear scanner allow in the context of thyroid cancer metastasis detection?

    <p>Detection of both metastatic and focal lesions</p> Signup and view all the answers

    How does surgical removal of thyroid tissue affect radioiodine therapy outcomes?

    <p>It limits the amount of iodine absorbed by any cancer left</p> Signup and view all the answers

    Study Notes

    Energy Windows

    • Energy windows around the photopeak should be symmetric.
    • Energy peak and window settings are camera-specific and should be established for each individual camera.
    • A 20% window is standard when using 99mTc.
    • For 201Tl a 30% window around the 70 keV peak and a 15% window around the 167 keV peak are sufficient.

    Collimation

    • It is recommended that a parallel-hole collimator be used for planar imaging.
    • For 99mTc, the low-energy, high-resolution collimator is usually best.
    • When using 201Tl, a low-energy, medium-resolution (all-purpose) collimator is best since the counting statistics become limited with a high-resolution collimator.

    SPECT Imaging

    • Single-head cameras are widely used.
    • Adding additional detectors doubles the acquired counts, reducing acquisition time.
    • Traditional orbits include circular, step-and-shoot motion using a rotational range of 180° or 360°.
    • For a 180° orbit, two detectors separated by 90° are ideal.
    • A 360° orbit ideally uses three detectors separated by 120°.
    • Elliptical orbits, common in modern SPECT systems, improve spatial resolution.
    • SPECT and CT integration offers potential benefits.
    • SPECT apparatus typically has a large FOV and dual detectors.
    • CT apparatus provides anatomical location, attenuation correction, and may include multi-slice units for standalone diagnostic scans.

    Positron Emission Tomography (PET) Imaging

    • Most dedicated PET cameras consist of rings of small detectors.
    • Commonly used crystal types include bismuth germinate (BGO), gadolinium oxyorthosilicate (GSO), lutetium oxyorthosilicate (LSO), and lutetium yttrium orthosilicate (LYSO).
    • PET scanners rely mainly on CT scans for attenuation correction, but can also use rotating-rod sources of germanium-68/gallium-68.

    Nuclear Cardiology

    • It has become a major component of nuclear medicine.
    • Technologists focused solely on performing cardiac studies may be eligible to sit for the nuclear cardiology specialty board exam.
    • It is essential to review topics such as instrumentation, quality control, patient care, the cardiovascular system, pathology, electrocardiogram (ECG), emergency care, radiopharmaceuticals, and interventional drugs.

    Planar Imaging

    • While no longer the standard approach for myocardial perfusion imaging, it can be an alternative for patients unable to have SPECT imaging due to body habitus or inability to remain in position.
    • A small field of view scintillation camera is practical for cardiac imaging.
    • Using a 10 in. field of view (FOV) with a matrix of 128 x 128 results in about 2 mm of pixel spacing.
    • A 15 in. FOV camera should be zoomed using a magnification of 1.2-1.5 to achieve pixel size close to 2 mm.

    Combined SPECT/CT Quality Control

    • Includes all SPECT and CT imaging quality control tests.
    • The CT portion must additionally perform registration, attenuation correction accuracy, and mis-registration consequences.

    Dedicated PET Imaging Quality Control

    • Suggested quality controls include acceptance testing, sensitivity, transverse resolution, scatter fraction, accuracy of attenuation correction, and any other test recommended by the manufacturer.
    • Sensitivity should be performed daily or at least weekly.
    • Transverse resolution should be performed annually using a point source or rod source.
    • It is also recommended that scatter fraction and accuracy of attenuation correction be performed annually.

    PET/CT Imaging Quality Control

    • The quality control of the PET portion of PET/CT includes all of the suggested quality controls for PET imaging.
    • The quality control of the CT portion of PET/CT also includes calibration and feild uniformity.

    Combined PET/CT Quality Control

    • Includes individual PET and CT portions as mentioned above, as well as registration and attenuation correction accuracy.

    Radionuclide PET/CT Generator

    • Radionuclide generators provide a convenient source of short-lived radionuclides.
    • In a radionuclide generator, a longer-lived radionuclide (parent) decays to a shorter-lived radionuclide (daughter).
    • The daughter can be removed periodically since it is replenished by decay of the parent.
    • Examples of parent-daughter systems used in radionuclide PET/CT generators are strontium-82 (82Sr)/rubidium-82 (82Rb).
    • These systems are commercially available as sterile, shielded, automatically operated devices.

    99mTc-Pyrophosphate

    • 99mTc-Pyrophosphate is used for cardiac amyloid imaging in Europe due to unavailability of other, more readily accessible radiopharmaceuticals like 99mTc-DPD
    • In the United States, 99mTc-methylene diphosphonate (99mTc-HMDP) is widely available but has lower sensitivity and is not recommended for cardiac amyloid imaging.

    Administration and Imaging

    • Recommended dose: 370-740 MBq (10-20 mCi) administered intravenously
    • Total radiation exposure from 555-MBq (15-mCi) dose: approximately 3 mSv
    • Imaging is performed 3 hours after intravenous injection, using planar and SPECT images of the patient's chest
    • Imaging typically utilizes a standard dual-head gamma camera with a 90" detector configuration
    • Recent research suggests feasibility of semiquantitative analysis of 3-dimensional images using cadmium-zinc-telluride cameras

    Indications

    • 99mTc-Pyrophosphate imaging is used to differentiate variant from wild-type cardiac ATTR in patients with suspected or known family history of amyloidosis
    • Also indicated for patients suspected of cardiac ATTR but with contraindications to cardiac MRI, such as implantable devices or renal insufficiency
    • In such cases, a negative serum and urine study for AL amyloidosis supports a diagnosis of ATTR cardiomyopathy

    Contraindications

    • No known specific contraindications other than general nuclear medicine procedure cautions regarding pregnancy, breastfeeding, and recent nuclear medicine scans

    Patient Preparation

    • No specific patient restrictions before 99mTc-pyrophosphate imaging
    • Patients can eat, drink, and take medications as usual
    • Patients are imaged supine with arms above their head, ensuring the entire ribcage is visualized

    Imaging Parameters

    • Planar images include anterior and left lateral projections
    • Imaging parameters vary among equipment but the parameters outlined in the 2021 addendum to the recommendations generally work well for most camera systems.

    Whole-Body Imaging

    • Whole-body imaging is not useful for 99mTc-pyrophosphate
    • However, whole-body imaging with 99mTc-HMDP or 99mTc-DPD demonstrates soft-tissue uptake
    • This is because the heart-to-contralateral-lung ratio is calculated to assess cardiac uptake
    • The camera should be large enough to image the complete chest to visualize rib uptake and enable this calculation

    Adrenal Gland Imaging

    • Adrenal lesions can have clinical signs and symptoms of endocrine hyperfunction or be discovered as masses or adrenal enlargement on cross-sectional imaging.
    • Incidental adrenal masses found on CT or MRI are common.
    • Nuclear medicine studies allow for selection of patients needing biopsy or surgical intervention, when clinically necessary.
    • FDG is poorly accumulated in normal adrenal glands, making PET/CT helpful in assessing and characterizing adrenal masses with increased activity.
    • This includes cancer patients and those with "incidentalomas" found on 5% of CT scans done for other reasons.
    • Up to 50% of adrenal masses in patients with a nonprimary adrenal malignancy may be benign.
    • Adrenal uptake is usually considered positive if it's greater than or equal to that in the liver or has a standardized uptake value (SUV) greater than 3.1.
    • PET/CT has about 90% accuracy in differentiating metastatic adrenal masses from benign lesions.
    • False negatives can occur due to small lesions, hemorrhage, and necrosis.
    • Approximately 5% of adrenal adenomas are hypermetabolic.

    Adrenal Medullary Imaging

    • Metaiodobenzylguanidine (MIBG) is a guanethidine analog similar to norepinephrine.
    • It's taken up by chromaffin cells, making it useful for imaging normal and abnormal sympathetic adrenergic tissue, especially pheochromocytomas and neuroblastomas.
    • MIBG is localized in other neuroendocrine tumors, including carcinoid, medullary thyroid carcinoma, and paraganglioma, but to a lesser degree.
    • In cases of pheochromocytoma and neuroblastoma, MIBG has high sensitivity and specificity, approaching 90%.
    • The specific radiopharmaceutical used is radioiodinated MIBG labeled with 3 to 10 mCi (81 to 370 MBq) of iodine-123 (123I).
    • Iodinated MIBG is slowly metabolized, with 75% to 90% excreted by the kidneys as unaltered MIBG.
    • Whole-body planar images or selected spot images of the regions of interest are obtained serially over 24 to 72 hours, depending on the suspected pathology.
    • Radioiodinated MIBG appears normally in the salivary glands and liver, with faint activity in the heart and thyroid gland.
    • Due to renal excretion, there is renal and bladder activity.
    • Nasal, neck muscle, diffuse lung activity, and bowel activity can be noted in some patients.
    • Normal adrenal medulla is visualized on delayed images in about 30% to 50% of patients, which can lead to false-positive results.
    • However, the intensity is usually less than the adjacent liver and needs to be distinguished from the more intense abnormal accumulation seen in pheochromocytoma or neuroblastoma, which is greater than the liver in 80% to 90% of patients.

    Clinical Applications

    • Pheochromocytomas are known as the "ten-percent tumors" because approximately 10% are bilateral, 10% occur in children, 10% are extraadrenal, and 10% are malignant.
    • Whole-body imaging augmented by SPECT or SPECT/CT with 123I-MIBG has been the method of choice for pheochromocytomas.
    • 18FDG and 68Ga DOTATATE PET/CT are also useful.
    • MIBG scans for pheochromocytomas are especially helpful in diseases with a high incidence of neoplasm, including multiple endocrine neoplasms types 2A and 2B, neurofibromatosis, von Hippel-Lindau disease, Carney triad, and familial pheochromocytoma.
    • The technique is sensitive in both adults and children.
    • Posterior adrenal images are obtained at 24, 48, or 72 hours, as needed.
    • Whole-body planar imaging is useful if ectopic lesions are suspected.
    • Pheochromocytomas imaged with radioiodinated MIBG present as focally increased activity, whether the tumor is located in the adrenal medulla or ectopically.
    • Radiopharmaceutical uptake is greater in well-differentiated tumors than in less well-differentiated tumors.
    • Occasionally, some large tumors are not visualized due to extensive tumor necrosis.
    • Imipramine, insulin, reserpine, tricyclic antidepressants, and amphetamine-like drugs may inhibit localization of radioiodinated MIBG, interfering with tumor imaging.
    • These should be withheld before imaging when practical.

    Neuroblastoma

    • MIBG can be used to detect adrenal medullary neuroblastoma and its metastases in more than 90% of affected neonates and children.
    • Whole-body imaging with or without SPECT or SPECT/CT is performed 24 and 48 hours after administration.
    • In normal subjects, the adrenal medulla can be seen on more delayed images, and diffuse lung and gut activity can be prominent.
    • Neuroblastomas & any metastases detected with MIBG present as foci of increased activity.
    • Skeletal and marrow metastases are usually best seen on 48-hour images.
    • Aggressive chemotherapy may hinder the detection of some metastases.
    • Imaging of neuroblastomas and pheochromocytomas using 111In-pentetreotide (a radiolabeled somatostatin analog) and 18F-FDG is discussed elsewhere.
    • 111In-pentetreotide may be limited for detecting adrenal lesions due to intense normal activity in nearby kidneys.

    Adrenal Glands

    • The adrenal glands consist of an outer adrenal cortex and an interior neurosecretory adrenal medulla.
    • Located in the retroperitoneum, superior to the kidneys (suprarenal), they lie approximately below the eleventh rib.
    • The right adrenal gland is higher and more posterior than the left, even though the left kidney is often higher than the right.
    • The right adrenal gland is triangular, sitting astride the upper pole of the right kidney.
    • The left adrenal gland is more crescent shaped and lies anteromedial to the upper pole of the left kidney.

    Adrenal Medulla

    • The adrenal medulla is typically located within the adrenal gland surrounded by the adrenal cortex.
    • Medullary tissue is quite small, with a cortex-to-medulla area ratio of approximately 10:1.
    • The adrenal medulla tissue synthesizes and secretes the catecholamines epinephrine and norepinephrine.
    • These hormones maintain (or increase) smooth muscle tone, heart rate and force of contraction, and other physiological responses associated with stress.

    Adrenal Medulla Clinical Aspects

    • Benign or malignant functioning tumors of adrenal medulla tissue are known as pheochromocytomas, which are hyperplastic nodules 1 cm in diameter or larger.
    • Smaller tumors are considered macronodular hyperplasia.
    • Despite their small size, these tumors can produce excessive amounts of epinephrine or norepinephrine, leading to undesirable symptoms.
    • These symptoms typically include hypertension and other consequences of excessive catecholamine production.
    • Pheochromocytomas can occur as apparently spontaneous benign or malignant tumors, but they may arise from any site of autonomic nervous tissue.
    • These tumors are frequent components of the hereditary syndrome multiple endocrine neoplasia (MEN) types IIa and IIb.
    • While advances in clinical chemistry have made direct assay of catecholamines and even specific assays of plasma and urinary epinephrine and norepinephrine more readily available, the disease is often a clinical enigma, frequently not diagnosed until postmortem examination.
    • Some tumors produce excessive amounts of catecholamines, but they do not secrete these products into the circulation, so patients may not present with typical clinical symptoms.
    • These nonsecretory tumors are called paragangliomas.
    • They can become malignant, invading surrounding tissue, metastasizing throughout the body, or both.
    • The small size of the adrenal medullary tissue and a propensity for ectopic sites make diagnosis even by CT and MRI unreliable.
    • 24 of 107 pheochromocytomas were found outside the adrenal glands in one large surgical series.

    Radionuclides

    • After many years of research, 131I-MIBG was approved by the FDA in the 1970s for clinical use as a diagnostic imaging agent.
    • Although cumbersome to work with, 131I-MIBG became the imaging agent of choice to identify normal, ectopic, or hyperfunctioning adrenal medullary tissue.
    • Subsequently, 123I-MIBG was synthesized, but the short half-life of 123I initially limited availability.
    • 123I-MIBG is now commercially accessible for routine use in nuclear medicine departments.
    • MIBG labeled with 123I or 131I can identify the extent of disease in patients with neuroblastoma, a malignant tumor of childhood that can be widely disseminated in the abdomen and bone marrow.
    • After secretion at the synapse, a portion of the norepinephrine is reabsorbed and stored in granules at the presynaptic site through a presynaptic reuptake mechanism.
    • MIBG has little or no pharmacological effect and does not significantly bind at postsynaptic receptors.
    • It's incorporated into the presynaptic adrenergic storage granules due to structural similarities to norepinephrine, providing the basis for visualization of adrenergic tissue in general and pheochromocytomas and paragangliomas in particular.

    99mTc Sestamibi for Breast Tumor Imaging

    • Administration: Intravenous injection in the arm contralateral to the involved breast
    • Reason for contralateral arm: To avoid potential radiation exposure to normal breast tissue

    Optimal Scanning Time for Neoplasm with 67Ga Citrate

    • Optimal time for 67Ga citrate imaging: 24 hours after injection

    Lymphoscintigraphy

    • Purpose: Mapping lymphatic channels, determining drainage pathways from malignant neoplasms, identifying the sentinel node

    111In Pentetreotide

    • Type: Somatostatin analog

    HAMA Response

    • Cause: Occurs when monoclonal antibodies, which are produced from mouse cells, are recognized as foreign proteins by the human body, triggering an immune response.

    111In Satumomab Pendetide Administration

    • Pre-Injection: Should be shielded and assayed

    111In Satumomab Pendetide Use

    • Target: Imaging of extrahepatic metastases from colorectal and ovarian cancer

    Advantages of 201Tl Chloride over 67Ga Citrate

    • Shorter half-life: Allows for imaging to be performed sooner
    • Less uptake in inflammatory processes: Improved specificity for detecting tumor

    99mTc Sestamibi for Breast Tumor Imaging

    • Specificity: Sestamibi has preferential uptake in breast tumors, allowing for distinct imaging

    Cross-Reaction with Monoclonal Antibodies

    • Definition: Monoclonal antibody binds to antigens other than the one it was originally designed for which can lead to off-target effects

    Neuroendocrine Tumor Examples

    • Examples: Pituitary adenomas, small-cell lung cancer, neuroblastomas

    Kidney Visualization with 111In Pentetreotide and 67Ga Citrate

    • 111In pentetreotide: Normal kidney visualization at 48 hours
    • 67Ga citrate: Abnormal kidney visualization at 48 hours

    18FDG for Tumor Imaging

    • Mechanism: 18FDG utilizes the higher glycolytic rate in tumors compared to normal tissues for imaging

    18FDG Tumor Imaging Considerations

    • Requirements: PET scanning, patient fasting prior to the exam
    • Target: 18FDG can detect a wide variety of tumors, not just brain tumors

    Pheochromocytomas

    • Imaging agent: 131I MIBG

    PET Imaging in Oncology

    • Advantage: Exploits metabolic differences between normal and neoplastic tissue

    Hodgkin's Disease

    • Type: Lymphoma

    Normal 67Ga Citrate Uptake Sites

    • Uptake locations: Intestinal mucosa, liver
    • Excluded location: Parathyroid glands

    F-18 Fluciclovine

    • FDA-approved indication: Imaging of prostate cancer

    Ga-68 Dotatate

    • Half-life: 68 minutes
    • Recommended dose: 0.054 mCi/kg up to 5.4 mCi
    • Production method: Cyclotron
    • Target: Neuroendocrine tumors

    Radiation Dosimetry for 67Ga-Citrate

    • Whole body radiation dose: 1.3 rad/5 mCi
    • Skeleton radiation dose: 2.2 rad/5 mCi
    • Liver radiation dose: 2.3 rad/5 mCi
    • Bone marrow radiation dose: 2.9 rad/5 mCi
    • Spleen radiation dose: 2.65 rad/5 mCi
    • Kidney radiation dose (calyx): 2.05 rad/5 mCi
    • Ovary radiation dose: 1.4 rad/5 mCi
    • Testes radiation dose: 1.2 rad/5 mCi
    • Stomach radiation dose: 1.1 rad/5 mCi
    • Small intestine radiation dose: 1.8 rad/5 mCi
    • Upper colon radiation dose: 4.5 rad/5 mCi

    111In-Oxine–Labeled White Blood Cells

    • Patient assessment before procedure is essential, including clinical history, current medications, laboratory tests, and recent imaging procedures.
    • Explain the blood labeling technique to the patient, including time requirements for imaging and physical requirements during the imaging procedure.
    • Blood labeling may be performed by a local radiopharmacy or in-house.
    • A minimum of 50 ml of blood should be withdrawn using an 18 to 20 gauge needle.
    • Label the blood sample and complete appropriate paperwork before sending to radiopharmacy or labeling in-house.
    • If labeling is done in-house, follow the approved protocol for 111In-oxine or 99mTc-HMPAO.
    • Correctly identify the patient before reinjecting the labeled blood product using a large bore needle (18 to 20 gauge, if possible).
    • Ask the patient to void and remove any clothing or metal objects that may cause attenuation artifacts on the images.
    • Perform an initial whole-body and/or static image protocol followed by a SPECT or SPECT/CT of the selected area. Imaging parameters depend on the radiopharmaceutical used for labeling.
    • Perform the delayed imaging protocol as per the interpreting physician's request.

    Radiation Dosimetry for 99mTc Leukocytes

    • Adult dose: 185 to 370 MBq (5 to 10 mCi) of 99mTc-exametazime (HMPAO) leukocytes
    • Largest Radiation Dose: Spleen receiving 0.56 mGy/MBq (0.063 rad/mCi)
    • Effective Dose: 0.017 mSv/MBq (0.063 rem/mCi)
    • Child (5 years old) dose: 3.7 MBq (0.1 to 0.2 mCi) of 99mTc-exametazime (HMPAO) leukocytes
    • Largest Radiation dose: Spleen receiving 1.8 mGy/MBq (0.020 rad/mCi)
    • Effective dose: 0.054 mSv/MBq (0.020 rem/mCi)

    Tumor Imaging

    • Parathyroid
    • Prostate cancer
    • Colorectal cancer
    • Neuroendocrine tumors
    • Pheochromocytoma and neuroblastoma
    • Breast cancer
    • Lung cancer

    Parathyroid Imaging

    • Radionuclide: 99mTc-sestamibi
    • Average adult dose: 20 mCi (740 MBq)
    • Flow study: acquired immediately after injection
    • First (thyroid) phase: begins 15 to 20 minutes post injection
    • Second (parathyroid) phase: 2 hours post injection

    Prostate Cancer Imaging

    • Radionuclide: Indium-111–capromab pendetide (ProstaScint)
    • Procedure performed over 96 to 120 hours
    • Day 1: 5 mCi (185 MBq) of 111In–capromab pendetide infused over 3 to 5 minutes
    • Blood pool activity can be imaged 30 minutes to 4 hours
    • For optimal targeting and minimal blood pool activity, imaging should be performed at 96 to 120 hours post injection

    Colorectal Cancer Imaging

    • Radionuclide: Technetium-99m-arcitumomab (CEA-Scan)

    111In Radionuclide Characteristics

    • Half-Life: 67.4 hours
    • Principal Radiations: 171 keV (90.0%) and 247 keV (94.2%)

    Radiation Dosimetry for 111In-Labeled White Blood Cells

    • Whole Body: 0.50 to 0.53 rad/mCi
    • Liver: 1 to 5 rad/mCi
    • Spleen: 18 to 20.4 rad/mCi

    99mTc-Exametazime (Ceretec)

    • Requires withdrawal of 40 to 50 ml of patient's blood
    • Adult dose: 7 to 25 mCi (259 to 925 MBq)
    • Anterior and posterior whole-body images are acquired after a delay of 4 to 24 hours
    • High-resolution, low-energy collimator is recommended. Low count rate on delayed images may benefit from the use of a low-energy, all-purpose collimator.
    • Additional static images and SPECT or SPECT/CT imaging can be helpful

    67Ga-Citrate

    • Initial imaging sequence: Whole body scan with static images or SPECT or SPECT/CT of the area of interest using a medium- or high-energy collimator
    • Count rate for WB images should be in the range of 1 to 2 million counts
    • Static images: 800,000 to 1 million counts
    • SPECT images: 64 × 64 or 128 × 128 matrix, 360-degree rotation with 3- to 6-degree sampling for 40 to 50 seconds/stop
    • Obtain CT images as per manufacturer’s protocol.
    • Repeat imaging sequence as directed by the interpreting physician for all subsequent imaging sets.
    • Process images as per institution's protocol for filtration and display.

    67Ga Radionuclide Characteristics

    • Production: 67Zn(p,n)67Ga or 68Zn(p,2n)67Ga
    • Half-Life: 78 hours
    • Principal Radiations: 0.093 MeV (40%), 0.184 MeV (24%), 0.296 MeV (22%), 0.388 MeV (7%)

    Purpose

    • The purpose of this document is to guide practitioners with performing, interpreting, and reporting results of 99mTc-sestamibi breast scintigraphy.

    Background Information and Definitions

    • Breast scintigraphy is performed after intravenous administration of 99mTc-sestamibi and includes planar and/or single-photon emission computed tomography (SPECT).

    Clinical or Research Applications

    • Evaluation of breast cancer in patients with nondiagnostic, equivocal, or difficult to interpret mammograms.
    • Identification of multicentric and multifocal carcinomas in patients with breast cancer tissue diagnosis.
    • Evaluation of neoadjuvant chemotherapy effectiveness for breast carcinoma.

    Procedure

    • Patient Preparation: No special preparation needed, but a thorough explanation of the test should be provided.
    • Information Pertinent to Performing the Procedure:
      • Obtain prior mammograms, ultrasounds, and MRIs if available.
      • A breast physical examination must be performed.
      • Determine the patient's last menses, pregnancy status, and lactating status.
      • Delay scintigraphy at least 2 weeks after cyst aspiration or fine needle aspiration, and 4–6 weeks after core or excisional biopsy.
      • The nuclear medicine physician should acknowledge any previous surgical procedures or therapy.
    • Precautions:
      • Inform patients about radiopharmaceutical infiltration and potential false-positive uptake in axillary lymph nodes.
    • Radiation Dosimetry: For adults, the gallbladder receives the largest radiation dose.
    • Image Acquisition:
      • Use a standard scintillation camera equipped with a low-energy, high-resolution collimator.
      • The patient lies prone with the breast to be imaged dependent from the imaging table.
      • A breast-positioning device should be used to minimize patient motion.
      • Images are acquired in different positions including prone, prone posterior oblique, prone lateral, posterior oblique, and anterior supine or upright chest.
    • Image Interpretation:
      • Focal increased uptake of the radiopharmaceutical is suspicious for malignancy.
      • Mild homogeneous uptake is consistent with a normal study.
      • Patchy or diffuse increased uptake is probably not malignant.
      • Interpret images from the computer monitor to adjust contrast.
    • Quality Control and Radiation Safety: Follow Society of Nuclear Medicine Procedure Guideline for Use of Radiopharmaceuticals.
    • Sources of Error:
      • Radiopharmaceutical infiltration may cause false-positive uptake in axillary lymph nodes.
      • Patient positioning that does not allow the breast to be fully dependent decreases test accuracy.
      • Patient motion decreases test accuracy.
      • Cross-talk of activity can lead to false-positive results.
      • Sensitivity, specificity, and accuracy depend on the size of the breast tumor.

    Issues Requiring Further Clarification

    • None provided in the document.

    Lymphoscintigraphy and Sentinel Node Localization in Breast Cancer

    • The accurate harvest of a sentinel node (SLN) in breast cancer involves a sequence of procedures with components from different medical specialties, such as nuclear medicine, radiology, surgical oncology and pathology.
    • These guidelines aim to promote the use of nuclear medicine procedures with high quality, by providing information about SLN detection in breast cancer patients.

    Radiopharmaceutical Administration

    • Activities as low as 3.7 MBq (0.1 mCi) and as high as 370 MBq (10 mCi) have been used for SLN procedures.
    • A total injected dose of 5 to 30 MBq is generally considered sufficient for surgery planned on the same day.
    • When injection is done the afternoon prior to surgery, up to 150 MBq is considered sufficient.
    • Small injection volumes (0.05-0.5 mL) are preferred with superficial injections (periareolar, subdermal, intradermal, or subareolar) due to the potential interference with normal lymphatic flow.
    • Larger volumes (0.5-1.0 mL) are used with peritumoral injections.
    • Gently rotate a syringe containing radiolabelled colloid particles immediately prior to administration to ensure good mixing. Avoid aggressive agitation.

    Injection Procedure

    • Popular injection techniques include peritumoral, subdermal, periareolar, intradermal, and subareolar injections.
    • All techniques have shown satisfactory SLN detection rates.
    • Superficial injections are easy to perform but may be more painful.
    • Peritumoral injections require thorough investigation of a patient's prior imaging and medical records, especially for non-palpable tumors.
    • Ultrasound guidance may assist in peritumoral injection placement.
    • Adding pH-balanced 1% lidocaine to the radiopharmaceutical can improve patient comfort.

    Blue Dye

    • Commonly used blue dyes for SLN procedures include patent blue V, isosulfan blue, and methylene blue.
    • Blue dye can be injected around the primary tumor, similar to radiopharmaceuticals, 10–20 minutes prior to surgery.
    • Administer 2–5 mL of blue dye.
    • Avoid injection into the dead space of a seroma.

    Imaging

    • Imaging is recommended before surgery to assess patient variability in lymphatic drainage.
    • The detector should be constructed to offer high shielding against radiation hitting the sides of the probe assembly.
    • The whole system should be designed and constructed for intraoperative use.

    SLN Nonvisualization

    • Most patients with preoperative lymphoscintigraphic SLN nonvisualization will have at least one SLN detected intraoperatively, either by gamma probe alone or by gamma probe combined with blue dye.
    • A second radiotracer injection may be beneficial for visualizing previously nonvisualized SLNs.
    • In approximately 1-2% of patients, SLNs will not be detected preoperatively or intraoperatively, and the status of the axillary nodes cannot be determined.
    • Old age, obesity, tumor location other than the upper outer quadrant, and nonvisualization of SLNs on preoperative LS may be associated with failed SLN localization.
    • The significance of preoperative scintigraphic nonvisualization is not yet known.

    Key Facts:

    • The final result of these guidelines has been discussed by distinguished experts from the EANM Oncology Committee, SNMMI, and ESSO.
    • These guidelines describe protocols currently used, but do not include all existing procedures.
    • It is important to remember that resources and facilities for patient care may vary.
    • Using the images and skin markings as guides, the probe can be used to select the optimum location for incision.
    • Remove the SLNs and check the wound site for remaining activity. Nodes closer than 15–20 mm may appear as one spot.
    • The current use of SPECT/CT can reveal the presence of a cluster of lymph nodes on CT images.
    • Radioactive waste in the operating room and pathology should be collected according to institutional radiation safety procedures.
    • Ensure all medical equipment has CE certification in the European Union and FDA approval in the USA.
    • Educational programs for surgical suite personnel and pathologists are valuable for establishing appropriate handling of radioactive materials.

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    Description

    This quiz covers essential concepts in nuclear medicine imaging, focusing specifically on energy windows, collimation, and SPECT imaging. Understand the camera-specific settings for energy peaks and window sizes as well as the recommended collimators for different isotopes like 99mTc and 201Tl. Test your knowledge on the methodologies used in SPECT imaging.

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