LM317A: LM317A Thermal Dissipation

LM317A SOT-223 package TJA is 59.6,  Tj= Ta+ (Rja*Power). Power=(Vin-Vout)I
So, if I use LM317A in TA= 85C, I=1.5A design, Vin-Vout shoud less than (TJ-TA)/Rja=(125C-85C)/59.6=0.67V? am I right

Is there any solution to improve heat dissipation without  adding additional heat sinks. in order to get I=1.5A , Vin-Vout> 4V using conditions

thanks!