Is it lawful for a female patient to travel without a Mahram for treatment?

Q: I am a sick girl who has to visit a hospital in Riyadh regularly, as there is no therapy for my illness in my country. My father died a long time ago, which makes me very worried whenever I have to go to the hospital because I find no one to accompany me to Riyadh. I have two paternal half brothers but they have been refusing to take me there since four years. I take medication and go back for a checkup two or four months later. They only accompanied me three times. Even when one of them accompanies me, he leaves me alone for a week or more. My maternal uncle also refuses to accompany me. Please be informed that I have a work which I need because of my circumstances and my employers warned me against absence for more than two days. (Part No. 17; Page No. 319) Furthermore, my nephews are still young and their parents do not let them go with me. Having so far given a detailed account of my circumstances, what is the ruling on my traveling by plane without a Mahram (spouse or permanently unmarriageable relative)? I would like to add that I am a practicing Muslim woman and I wear full Hijab (veil), but I suffer from adverse circumstances.

A: It is not permissible for you to travel without a Mahram. The Prophet (peace be upon him) is authentically reported to have said: A woman should not travel except with a Mahram. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.