Pegylated fluoroalkoxybenzamide compounds which selectively bind Sigma-2 receptors are disclosed. These compounds, when labeled with a positron-emitting radioisotope such as 18F, can be used as radiotracers for medical imaging such as imaging of tumors by positron emission tomography (PET). In addition, these compounds, when labeled with 123I, can be used as radiotracers for imaging of tumors by single photon emission computed tomography (SPECT). Methods for synthesis of these compounds are also disclosed.