The present disclosure provides an apparatus for determining a location of a wireless marker for a tumor, the apparatus comprising: a phased array antenna, and a processor, wherein the processor is configured to control the phased array antenna to transmit a wireless signal to the wireless marker, receive a wireless signal transmitted by the wireless marker in response to the transmitted wireless signal, and analyze the wireless signals transmitted and received by the phased array antenna to determine a location of the wireless marker. The present disclosure also provides a method for determining a location of a wireless marker for a tumor, wherein the method comprises: transmitting, using a phased antenna array, a wireless signal to the wireless marker, receiving, at the phased antenna array, a wireless signal transmitted by the wireless marker in response to the transmitted wireless signal, and analyzing the wireless signals transmitted and received by the phased array antenna to determine a location of the wireless marker.