The part of the sentence "twice every week" is correct and usable in written English.
It can be used when referring to something that happens on a regular basis. For example, "I exercise twice every week."
I estimate that I talk to my wife daily and my two children at least twice every week.
Twice every week, she rode two trains and a bus to the hospital for exhausting blood transfusions.
A neuroscientist is getting a brain scan twice every week for a year to try to see how neural networks behave over time.
"Shells have been falling once or twice every week.
Each student was required to post at least twice every week and advised to post one new post and one response to other's posts.
Use platforms like Buffer to schedule valuable content once or twice every week before you launch your campaign.
Mice were intraperitoneally injected with 2.5x10 OT-1 CD8+ T cells twice, every other week.
The implanted pumps were replaced twice every 4 weeks; thus, the total experimental period was 12 weeks.
Either 1 × 105 or 5 × 105 cells were injected into the mice twice every 2 weeks, and then the mice were sacrificed 3 weeks after the last injection to evaluate the pathological changes.
Cultured Treg cells and CCR2-Treg cells (1 × 105 or 5 × 105 cells) were transferred through retro-orbital venous plexus into 12-week-old MRL/lpr mice (at the early stage of sialadenitis and pneumonitis) twice every 2 weeks.
Paclitaxel (120 mg/body) was administered weekly, twice every 4 weeks for four courses, after which it was replaced by S-1 because of difficulty in securing vascular access.
