 The study evaluated the functionality and usability of a mobile app called Amor Mama, which guides and monitors patients with breast cancer undergoing radiation therapy. Only one item of the evaluation tool obtained a concordance index less than 80%, suggesting that the app is suitable for use in an educational health technology to guide and monitor patients with breast cancer undergoing radiation therapy. More studies should be conducted to assess the performance and quality of the mobile app during its use. This article was authored by Flavia Oliveira de Almeida Marquez de Cruz, Edison Tostfaria, Pablo Cardolino-Gobad and others.