British photographer Andy Whelan has routinely shared photos of his daughter Jessica during her 13-month fight against stage four neuroblastoma on this Facebook page.
But he described the black-and-white photo of his daughter writhing in pain, with tears streaming down her face as "the hardest photograph I have ever made."
"This is the true face of cancer, my baby girl's blood vessels protruding from beneath her skin, a solitary tear running down her cheek, her body stiffened and her face contorted in pain," Whelan wrote on Facebook.
Whelan said he shared the painful photo not to upset anyone, but to bring awareness to childhood cancer.
"Please I beg of you, as a heartbroken father, it is too late for my daughter, but childhood cancer needs to be cured. No family should have to go through this hell," Whelan wrote.
Read his full Facebook post below.