Technetium-99m APD compared with technetium-99m MDP as a bone scanning agent.

Area of Science:

• Nuclear Medicine
• Radiopharmacology
• Diagnostic Imaging

Background:

• Bone scintigraphy is crucial for diagnosing bone metastases and primary bone diseases.
• Technetium-99m-labeled bisphosphonates are commonly used bone imaging agents.
• Evaluating novel radiopharmaceuticals for improved diagnostic accuracy and safety is ongoing.

Purpose of the Study:

• To compare the efficacy and safety of technetium-99m-(-3-aminohydroxypropylidene)-1-1-bisphosphonate ([99mTc]APD) with technetium-99m-methylene-bisphosphonate ([99mTc]MDP) as bone scanning agents.
• To assess pharmacokinetic properties and diagnostic performance in normal subjects and patients.

Main Methods:

• [99mTc]APD and [99mTc]MDP were synthesized using an electrolytic labeling method with <1% free pertechnetate.
• Plasma disappearance half-life (T1/2) and 24-hour whole-body retention (WBR) were measured in normal subjects.
• Bone-to-soft-tissue ratios (B/ST) and lesion-to-normal bone ratios were evaluated in patients with suspected bone disease.

Main Results:

• [99mTc]APD exhibited a significantly lower 24-hr WBR (17.6% ± 4.6) compared to [99mTc]MDP (28.6% ± 3.9, p < 0.001).
• Bone/soft-tissue ratios were comparable between [99mTc]APD and [99mTc]MDP.
• Both agents demonstrated similar findings and positive results in patients with suspected bone metastasis or primary bone disease, with comparable lesion/normal bone ratios.

Conclusions:

• [99mTc]APD is a suitable agent for bone scintigraphy, offering potentially improved pharmacokinetic profiles.
• The diagnostic performance of [99mTc]APD is comparable to that of [99mTc]MDP.
• No adverse reactions were observed with [99mTc]APD, even at doses significantly lower than therapeutic oral bisphosphonate doses.