How to add options for radius? (Google Places API)

Question

Here is my code for obtaining addresses using Google Places API.

It returns matching addresses too far afield. I need to restrict it by radius how would I add my starting location to this code?

<script type="text/javascript" src="https://maps.googleapis.com/maps/api/js? 
key=XXXXXXX&libraries=places"></script>

<script type="text/javascript">  
var options = {

    componentRestrictions: { country: "uk" } 

 };

google.maps.event.addDomListener(window, 'load', function () {
    var places = new 
google.maps.places.Autocomplete(document.getElementById('<%=txtLocation.ClientID %>'), 
options);
google.maps.event.addListener(places, 'place_changed', function () {

        var place = places.getPlace();
        var latitude = place.geometry.location.lat();
        var longitude = place.geometry.location.lng();
         hf1.Set("FullDestination", place.formatted_address);
        hf1.Set("Latitude", latitude);
        hf1.Set("Longitude", longitude);
        
        document.getElementById('<%=txtLocation.ClientID %>').value = 
        place.formatted_address;

        }); 
        });
        </script>