## **Core Concept**
The question tests knowledge of radioisotopes used in nuclear medicine, specifically those administered systemically for therapeutic purposes. Systemic radionuclides are used to treat various conditions, including certain types of cancer and bone pain. These radioisotopes emit radiation that can kill cancer cells or alleviate symptoms.

## **Why the Correct Answer is Right**
Strontium-89 (Sr-89) and Samarium-153 (Sm-153) are examples of radioisotopes used systemically for the treatment of bone pain associated with metastatic bone disease. Radium-223 (Ra-223) is used for the treatment of bone metastases in prostate cancer. However, Yttrium-90 (Y-90) microspheres are primarily used for selective internal radiation therapy (SIRT) directly into the liver via the hepatic artery to treat liver tumors and certain types of liver metastases, not typically considered a systemic administration in the traditional sense like the others.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Not provided, as the option details are missing.
- **Option B:** Not provided, as the option details are missing.
- **Option C:** Not provided, as the option details are missing.
- **Option D:** This option corresponds to the correct answer but without details on the radioisotope, it's challenging to provide a specific reason.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that systemic radionuclides are often used for their ability to target specific diseases like bone metastases (e.g., Sr-89, Sm-153) or certain cancers (e.g., Ra-223 for prostate cancer). These treatments can help alleviate symptoms such as bone pain.

## **Correct Answer:** D.