(CNN) President Donald Trump's travel ban is throwing up road blocks for a US citizen who needs a bone marrow transplant that could save his life.

Maziar Hashemi, 60, was diagnosed with myelodysplastic syndrome, a type of blood cancer, in September. His doctors say the only treatment that can cure his cancer is a bone marrow transplant. Maziar Hashemi's brother, Kamiar Hashemi, is a 100% bone marrow match to Maziar, but he lives in Iran.

Iran is one of eight countries subject to restrictions on their citizens entering the United States as part of a Trump administration policy implemented in December . Under this policy, people from Iran -- both immigrants and visitors -- are prevented from entering the United States unless they are students, scholars or have an exchange visitor visa. Iranians can still apply for visas, but many have been denied since the ban took effect, although waivers can be granted.

Maziar Hashemi came to the United States to study civil engineering in 1975 and he is a naturalized citizen. He works as a civil engineer, but has not been working since October because he has been in and out of the hospital. His brother and sister still live in Iran.

Kamiar Hashemi applied for a visa to come to the United States in February so he could have the bone marrow transplant surgery at the hospital in Massachusetts where his brother is being treated. His visa was denied the same day he had a visa application interview at a US Embassy in Armenia. After he received the rejection, he submitted an application for a visa waiver.

Read More