Resumen: Psychophysiological arousal was observed in cancer patients during the application of relaxation techniques prior to a diagnostic scan (PET-CT). The aim of the study is twofold: firstly, it is sought to establish whether such techniques can minimize patient arousal before diagnostic screening begins, and secondly to measure which of them are most effective. The dependent variable is electrodermal activity, recording the attentional level and emotional response, and the independent variable comprises the relaxation techniques used, namely Jacobson, breathing and visualization. The 39 patients were split into experimental groups to whom the relaxation techniques (Jacobson, breathing exercises, and visualization) were applied before they went for the PET-CT. An activity-module procedure was applied to track electrodermal activity during the relaxation sessions, consisting of instructions, timeout; wait, task; relaxation and end of the recording session. The control group received no relaxation techniques before the PET-CT. Session-end results show that patients who perform relaxation techniques achieve greater attentional focus using Jacobson''s technique (M = .212) and enhanced emotional containment using visualization (M = .206). It is concluded that relaxation techniques minimize the state of activation during the waiting period before a diagnostic scan. Idioma: Español DOI: 10.1016/j.sumpsi.2016.06.002 Año: 2016 Publicado en: Suma Psicologica 23, 2 (2016), 133-140 ISSN: 0121-4381 Factor impacto SCIMAGO: 0.234 - Psychology (miscellaneous) (Q3)