Element most commonly used in brachytherapy of carcinoma cervix: March 2005
**Core Concept**
Brachytherapy is a form of radiation therapy where a radioactive source is placed inside or near the tumor to deliver a high dose of radiation to the target area. In the treatment of carcinoma cervix, the radioactive source is typically placed inside the uterus or in close proximity to the tumor.
**Why the Correct Answer is Right**
The most commonly used element in brachytherapy for carcinoma cervix is **Iodine-192**. This is because Iodine-192 emits beta and gamma radiation, which can be precisely controlled and delivered to the tumor site. The beta radiation has a short range and can be used to treat small tumors, while the gamma radiation has a longer range and can be used to treat larger tumors. The use of Iodine-192 in brachytherapy for carcinoma cervix has been well established and is a standard treatment modality.
**Why Each Wrong Option is Incorrect**
* **Option A:** This is not the correct answer, as Iodine-192 is the most commonly used element in brachytherapy for carcinoma cervix. Other elements like Iridium-192 are also used, but Iodine-192 is more commonly used.
* **Option B:** This option is incorrect, as Cesium-137 is used in brachytherapy, but it is not the most commonly used element for carcinoma cervix. Cesium-137 has a longer half-life than Iodine-192 and is often used for external beam radiation therapy.
* **Option C:** This option is incorrect, as Gold-198 is not commonly used in brachytherapy for carcinoma cervix. Gold-198 has been used in the past for brachytherapy, but it has largely been replaced by Iodine-192.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the choice of radioactive source in brachytherapy depends on the type and location of the tumor, as well as the desired radiation dose. Iodine-192 is a popular choice for carcinoma cervix due to its precise control and delivery of radiation.
**Correct Answer:** C.