得知UIImageView中那个cell被点击

请问，我创建了tableView，用到自定义单元，用图片定义复选框（UIImageView），如下：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *CellIdentifier = @"cellIdentifier";
    StandardCellWithImage *cell = (StandardCellWithImage *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if(cell == nil) {
        cell = [[StandardCellWithImage alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
        cell.selectionStyle = UITableViewCellSeparatorStyleNone;
    }

    cell.checkbox.tag = indexPath.row;
    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(didSelectedImageAtIndexPath:)];
    tapGesture.numberOfTapsRequired = 1;
    tapGesture.delegate = self;
    [cell.checkbox addGestureRecognizer:tapGesture];
    cell.checkbox.userInteractionEnabled = YES;

    return cell;
}


在didSelectedImageAtIndexPath方法中：
- (void) didSelectedImageAtIndexPath:(id) sender {
    UITapGestureRecognizer *gesture = (UITapGestureRecognizer *) sender;
    NSIndexPath *indexPath = [NSIndexPath indexPathForRow:gesture.view.tag inSection:0];
}

目前我只能知道用户点击了哪行，我想知道用户点击的具体位置，不知道应该怎么实现？