LDRs, or light-dependent resistors, can detect X-rays, but their sensitivity is low, making them inefficient for this purpose. The discussion highlights that while LDRs, typically made of CdS, respond to X-rays, they are not ideal for accurate detection. Alternatives like semiconductor crystals are mentioned, which can form electron-hole pairs and provide better sensitivity. The conversation also suggests exploring phosphor coatings used in fluorescent lights or CRTs for improved detection capabilities. Overall, while LDRs can detect X-rays, their effectiveness is limited compared to other methods.