Afterwards, he received further specialist training in interstitial brachytherapy for head and neck cancers and sarcoma in Institut Gustave Roussy in Paris, France and novel radiation techniques like stereotactic radiosurgery and stereotactic ablative radiotherapy in Stanford University USA. In 2013, he received further training on stereotactic body radiation therapy for liver tumors at Princess Margaret Hospital, Toronto, Canada. More recently in 2015 he was awarded HKCR 15A Traveling Fellowship and pursued subspecialty training in image-guided brachytherapy for cervical cancer and pediatric oncology. His current interests include clinical and genetic studies on nasopharyngeal cancer, head and neck cancers, lung cancers, liver cancers and gastrointestinal cancers. He has published extensively in these respects. In addition, he has special interest in dosimetric studies on intensity-modulated radiation therapy, stereotactic radiosurgery and selective internal radiation therapy with Yttrium-90 microspheres for liver tumors.