2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/222224We present a family of closed form inversion formulas in thermoacoustic tomography in the case of a constant sound speed. The formulas are presented in both time-domain and frequency-domain versions. As special cases, they imply most of the previously known filtered backprojection type formulas.27 pages, no figure, thanks addedAnalysis of PDEs92C55; 35L05; 35R30 (Primary); 44A99; 45Q05 (Secondary)text