{Reference Type}: Journal Article {Title}: Addressing challenges in low-income and middle-income countries through novel radiotherapy research opportunities. {Author}: Abdel-Wahab M;Coleman CN;Eriksen JG;Lee P;Kraus R;Harsdorf E;Lee B;Dicker A;Hahn E;Agarwal JP;Prasanna PGS;MacManus M;Keall P;Mayr NA;Jereczek-Fossa BA;Giammarile F;Kim IA;Aggarwal A;Lewison G;Lu JJ;Guedes de Castro D;Kong FS;Afifi H;Sharp H;Vanderpuye V;Olasinde T;Atrash F;Goethals L;Corn BW; {Journal}: Lancet Oncol {Volume}: 25 {Issue}: 6 {Year}: 2024 Jun {Factor}: 54.433 {DOI}: 10.1016/S1470-2045(24)00038-X {Abstract}: Although radiotherapy continues to evolve as a mainstay of the oncological armamentarium, research and innovation in radiotherapy in low-income and middle-income countries (LMICs) faces challenges. This third Series paper examines the current state of LMIC radiotherapy research and provides new data from a 2022 survey undertaken by the International Atomic Energy Agency and new data on funding. In the context of LMIC-related challenges and impediments, we explore several developments and advances-such as deep phenotyping, real-time targeting, and artificial intelligence-to flag specific opportunities with applicability and relevance for resource-constrained settings. Given the pressing nature of cancer in LMICs, we also highlight some best practices and address the broader need to develop the research workforce of the future. This Series paper thereby serves as a resource for radiation professionals.