Medical1: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/Medical1 - from package: vtk-examples

You may install the required package with command yum install {package}
Error in other languages:
Medical1: bevel nie gevind nie
Medical1: comandă negăsită
Medical1: comando não encontrado
Medical1: commande introuvable
Medical1: command not found
Medical1: käsku ei ole
Medical1: không tìm thấy lệnh
Medical1: komanda nerasta
Medical1: Kommando nicht gefunden.
Medical1: kommandot finns inte
Medical1: komut yok
Medical1: nie znaleziono polecenia
Medical1: níor aimsíodh an t-ordú
Medical1: no se encontró la orden
Medical1: no s'ha trobat l'ordre
Medical1: opdracht niet gevonden
Medical1: parancs nem található
Medical1: perintah tidak ditemukan
Medical1: príkaz nenájdený
Medical1: příkaz nenalezen
Medical1: команда не найдена
Medical1: командата не е открита
Medical1: 命令找不到
Medical1: コマンドが見つかりません