Mass Mobile Radiography Service Dr. Summerskill asked the Secretary of State for Social Services for which particular groups of people the Mass Mobile Radiography Service continues to be needed. Mr. Alison The Service will continue to be needed for those population groups who are known to have a higher incidence of respiratory tuberculosis than the general population, for example, the inmates of prisons and borstals; for other groups at risk such as people who have been in contact with an infected person; and for people living in areas where direct referral to hospital is not practicable.