Mechanical and imaging properties of a clinical-grade kidney phantom based on polydimethylsiloxane and elastomer by Kamal, Izdihar, Abdul Razak, Hairil Rashmizal, Abdul Karim, Muhammad Khalis, Mashohor, Syamsiah, Ying, Josephine Chyi Liew, Low, Yiin Jian, Zaaba, Nur Atiqah, Mazlan, Norkhairunnisa, Mohd Rafi, Nur Athirah Syima