Preparation and Imaging Guidelines for Pediatric Neuroblastoma MIBG Scans

Thyroid Blockade (Mandatory)

• The European Association of Nuclear Medicine (EANM) recommends initiating thyroid protection with saturated potassium iodide (SSKI) or Lugol’s solution at least 24 hours before ¹²I‑MIBG injection and continuing for 1–2 weeks afterward to prevent free radioactive iodide uptake by the thyroid gland【1】【2】.
• Verification of patient compliance with the thyroid‑blocking regimen during the pre‑procedure check‑in is identified as a critical safety step to avoid thyroid radiation exposure【2】.

Hydration and Bladder Management

• Adequate hydration is essential for optimal image quality; oral fluids (e.g., breast milk, formula, water, or non‑caffeinated drinks) are sufficient for most children, while intravenous hydration should be used for debilitated or fasting patients【1】【2】.
• Emptying the bladder immediately before image acquisition reduces pelvic artifacts, improves patient comfort, and lowers radiation dose to pelvic organs; strategies include stimulating urination with running water, upright positioning, or encouraging ambulation in young children【1】【2】.
• For infants and toddlers, diaper changes should be performed before scanning, and pelvic‑centered images should be obtained first when multiple body regions are imaged【1】【2】.

Pre‑Procedure Assessment

• The EANM advises collecting baseline data (weight, height, medical history, current medications, and existing intravenous access) and confirming thyroid‑blockade compliance prior to radiotracer administration【2】.
• In adolescent females of reproductive age, pregnancy testing must be performed to avoid fetal radiation exposure【2】.
• Review of concomitant medications that could interfere with ¹²I‑MIBG uptake is required, with specific drug‑interaction checks referenced in institutional nuclear‑medicine protocols【2】.

Injection Preparation

• Pre‑planning of intravenous access—preferably using an existing peripheral catheter and flushing with adequate saline—minimizes trauma and improves cooperation in children【1】【2】.
• Application of a topical anesthetic cream (e.g., lidocaine/prilocaine) 1 hour before venipuncture reduces procedural pain and facilitates successful IV placement【1】.
• Securing the peripheral IV catheter is recommended to prevent extravasation and avoid additional punctures in young patients【1】.
• Use of distraction techniques (e.g., stickers, badges) and positive reinforcement enhances patient cooperation during the procedure【1】.

Imaging Protocol and Staging

• The National Comprehensive Cancer Network (NCCN) guideline designates ¹²I‑MIBG as the preferred tracer for neuroblastoma imaging, achieving uptake in up to 90 % of tumors, reflecting high specificity and sensitivity【3】.
• SPECT or SPECT/CT should be performed at sites of known or suspected disease to improve lesion detection and anatomic localization【3】.
• When MIBG‑non‑avid disease is suspected or confirmed, ¹⁸F‑FDG‑PET is recommended (except in infants < 6 months with small L1 adrenal tumors) to assess metabolically active lesions【3】.
• Imaging must be obtained promptly for International Neuroblastoma Risk Group (INRG) staging but should not delay emergent therapy when clinically indicated【3】.

Common Pitfalls to Avoid

• Failure to confirm thyroid‑blockade compliance is the most frequent error and should be systematically checked before tracer administration【2】.
• Inadequate hydration leads to suboptimal image quality and increased radiation exposure; ensure appropriate fluid intake or IV support as needed【1】【2】.
• Not emptying the bladder prior to scanning results in pelvic artifacts and unnecessary radiation to pelvic organs; incorporate bladder‑voiding protocols into the workflow【1】【2】.
• Delaying the MIBG scan for staging can postpone INRG risk assessment; schedule imaging as early as possible in the diagnostic pathway【3】.

Guidelines for Preparing Pediatric Patients for ¹²³I‑MIBG Scans

Thyroid Blockade

• Ensuring thyroid protection is the most critical preparation step to prevent uptake of free radioactive iodide in children undergoing ¹²³I‑MIBG imaging. 4, 5
• Systematic verification of patient compliance with thyroid blockade during the pre‑procedure check‑in is the single most important safety measure and the most frequently missed error; confirming compliance before tracer administration avoids preventable thyroid radiation exposure. 4

Hydration Protocol

• Adequate hydration is essential to achieve optimal image quality and to reduce radiation dose to non‑target tissues in pediatric patients. 5
• For most children, oral hydration with appropriate fluids (e.g., breast milk, formula, plain water, or non‑caffeinated soft drinks) is sufficient. 5
• Intravenous hydration should be provided for debilitated children or those who are fasting to ensure adequate fluid status. 5
• Sugar‑containing liquids should be avoided when a child is fasting for other clinical reasons. 5

Bladder Management

• Emptying the bladder immediately before image acquisition is mandatory to reduce pelvic artifacts, improve patient comfort, and lower radiation dose to pelvic organs. 5
• Effective techniques for young children include playing the sound of running water, holding the child in an upright position, and encouraging ambulation. 5
• For infants, diapers should be changed immediately before scanning, and pelvic‑centered imaging should be performed first when multiple body regions are imaged. 5
• Routine bladder catheterization is rarely indicated because of infection risk and increased patient distress. 5

Pre‑Procedure Assessment

• Prior to tracer administration, collect baseline information including weight and height for dose calculation, a complete medical history, current treatment regimen, availability of intravenous access, and pregnancy testing for adolescent females of reproductive age. 4, 5

Intravenous Access Preparation

• Pre‑planning intravenous (IV) access minimizes procedural trauma and improves cooperation for subsequent imaging steps. 4
• Apply a topical anesthetic cream (e.g., lidocaine/prilocaine) one hour before venipuncture to reduce pain. 4
• Use an existing peripheral or central catheter when available to avoid unnecessary needle sticks. 4
• After tracer injection, flush the IV line with an adequate volume of saline to ensure complete delivery of the radiotracer. 4
• Employ distraction techniques such as favorite toys, stickers, or badges to ease anxiety. 5
• Maintain continuous conversation with the child throughout the procedure to provide reassurance. 4
• Allow a caregiver to remain present for the duration of the preparation and imaging process. 4, 5