4D scan at Dr. Tsang's clinic costs HK$600 with VHS or $700 with DVD, this fee also includes medicine.
Just book as usual is fine. That is I didn't specify that I would like to do a 4D scan when made the appointment with the nurse.
I don't think Dr. Tsang will do the scan 求其 after working hours. I had my 4D scan on weekday after work, he did the scan for me very carefully. The recording time of the DVD is over 30 mins.