(89)Sr bremsstrahlung single photon emission computed tomography using a gamma camera for bone metastases

Area of Science:

• Nuclear Medicine
• Radiopharmaceutical Imaging
• Oncology

Background:

• Strontium-89 chloride (89Sr) is a radiopharmaceutical used for palliative treatment of bone metastases.
• Assessing the detailed distribution of 89Sr is crucial for understanding its efficacy and potential side effects.
• Current imaging methods like planar imaging may not provide sufficient detail for whole-body 89Sr distribution.

Purpose of the Study:

• To evaluate Strontium-89 chloride (89Sr) bremsstrahlung single photon emission computed tomography (SPECT) imaging for detecting more detailed whole-body 89Sr distribution.
• To compare the efficacy of 89Sr SPECT with planar imaging in detecting bone metastases.
• To assess the incidence of extra-osseous uptake, specifically in the intestine.

Main Methods:

• Acquired whole-body planar and merged SPECT images using a two-detector SPECT system with specific energy windows for 89Sr bremsstrahlung.
• Evaluated thirteen patients with multiple bone metastases, comparing 89Sr imaging with 99mTc-HMDP imaging as a reference standard.
• Quantified hot spot detection in 35 defined bone regions and assessed intestinal 89Sr accumulation on planar images.

Main Results:

• Merged 89Sr SPECT imaging detected 66% of metastatic lesions compared to 56% with planar imaging, based on 99mTc-HMDP reference.
• A total of 195 bone metastatic lesions were identified across both imaging modalities.
• Intestinal 89Sr accumulation was observed in 38% of patients (5 out of 13).

Conclusions:

• Strontium-89 chloride (89Sr) bremsstrahlung-merged SPECT imaging provides more detailed whole-body distribution information than planar imaging.
• SPECT imaging enhances the detection of bone metastases treated with 89Sr.
• Physiologic excretion of 89Sr in the intestine was confirmed, with accumulation detected for up to 4 days post-injection.