It is hoped the technique will encourage cells damaged by the disease to grow again, Sky News reported.
The protein, known as glial cell line-derived neurotrophic factor (GDNF), is injected once a month through a port just behind the ear and pushed through the tubes and catheters by an external pump.
Doctors at Frenchay Hospital, Bristol, have trialled the system on six patients and are now looking for another 36 to continue the research.
"For years, the potential of GDNF as a treatment for Parkinson's has remained one of the great unanswered research questions," Dr Kieran Breen, director of research and innovation at Parkinson's UK, said.
"This new study will take us one step closer to finally answering this question once and for all."
"We believe GDNF could have the potential to unlock a new approach for treating Parkinson's that may be able to slow down and ultimately stop the progression of the condition all together," Breen said.