Hematologic malignancies, including leukemia, lymphoma, and multiple myeloma, continue to challenge clinicians with complex treatment regimens that often involve significant side effects and limited success, especially in advanced stages. Recent advancements in nuclear medicine have introduced theranostic strategies that merge diagnostic imaging with targeted therapeutic approaches, offering the potential for more precise and personalized treatment. A key area of progress lies in the development of alpha-emitting radiopharmaceuticals, such as Ac, At, or Pb, which can deliver potent radiation directly to tumor cells, sparing healthy tissue and minimizing collateral damage. In parallel with these therapeutic advancements, molecular imaging using radiolabeled agents enables better disease monitoring, assessment of treatment efficacy, and personalized management of patients with hematologic malignancies. The integration of diagnostic imaging with radiotherapy allows for a more tailored approach, where treatment can be adjusted based on real-time information about tumor progression and response. This review examines the recent strides made in both the development of radiopharmaceuticals and their applications in molecular imaging, with a focus on the potential to improve precision, reduce toxicity, and optimize patient outcomes. The synergy between targeted therapy and molecular imaging represents a transformative shift in the management of hematologic malignancies. As these technologies evolve, they are poised to redefine treatment paradigms, offering new hope for patients and potentially improving survival rates with more effective and less toxic treatment options.