Medical3: command not found

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/Medical3 - from package: vtk-examples

You may install the required package with command yum install {package}

Error in other languages:
Medical3: bevel nie gevind nie
Medical3: comandă negăsită
Medical3: comando não encontrado
Medical3: commande introuvable
Medical3: command not found
Medical3: käsku ei ole
Medical3: không tìm thấy lệnh
Medical3: komanda nerasta
Medical3: Kommando nicht gefunden.
Medical3: kommandot finns inte
Medical3: komut yok
Medical3: nie znaleziono polecenia
Medical3: níor aimsíodh an t-ordú
Medical3: no se encontró la orden
Medical3: no s'ha trobat l'ordre
Medical3: opdracht niet gevonden
Medical3: parancs nem található
Medical3: perintah tidak ditemukan
Medical3: príkaz nenájdený
Medical3: příkaz nenalezen
Medical3: команда не найдена
Medical3: командата не е открита
Medical3: 命令找不到
Medical3: コマンドが見つかりません