Fig. 1. Diagram of the vein and its surrounding tissues, including blood (zone Ⅰ), venous wall (zone Ⅱ), and perivenous tissue (zone Ⅲ)

Fig. 2. The radial 2ring fiber. (a) Photomicrogragh of the tip of the radial 2ring fiber^[11]; (b) simulation model for estimation

Fig. 3. Change of maximal temperature that is higher than initial temperature, λ=1470nm. (a) P=4.8W; (b) P=12.8W

Fig. 4. Temperature change at each probe location, λ=1470nm, P=5W, v=1m/s, E_d =50J/cm. (a) Radial fiber; (b) radial 2ring fiber

Fig. 5. The proportion of necrotic tissue in the vein and its surrounding tissues, λ=1470m, P=5W, v=1m/s, E_d=50J/cm.(a) Radial fiber, yz medium section, x=0; (b) radial fiber, xy medium section, z=40m; (c) radial 2ring fiber, yz medium section, x=0; (d) radial 2ring fiber, xy medium section, z=40m

Fig. 6. The proportion of necrotic tissue in vein and surrounding tissues under radial 2ring fiber irradiation,λ=1470nm, v=2mm/s. (a) P=5W, yz middle section, x=0, E_d = 25J/cm; (b) P=5W, xy medium section, z=40mm, E_d =25J/cm; (c) P=10W, yz middle section, x=0, E_d =50J/cm; (d) P=10W, xy medium section, z=40mm, E_d =50J/cm

Fig. 7. Temperature changes at each probe location, λ=1470nm, v=2mm/s. (a) P=5W, E_d=25J/cm; (b) P=10W, E_d =50J/cm

Fig. 8. Dynamic and static thermophysical parameters numerical simulation of radial 2ring fiber irradiation,λ=1470nm, P=5W, v=1mm/s

Fig. 9. The proportion of necrotic tissue in the vein and its surrounding tissues. The inner diameter of the vein is 5mm, λ=1470nm, P=10W, v=1mm/s, E_d=100J/cm. (a) yz medium section, x=0; (b) xy medium section, z=40mm