Mr Gonzales was commenting on University of Otago research showing southern rural patients overall received fewer scans than people in Dunedin and Invercargill.
In Oamaru, where a scanner was installed in 2008, rates were found to be on par with Dunedin, after an initial spike in use.
Published in the journal Health Policy, the study was led by Dr Garry Nixon, a rural health researcher in the Dunedin School of Medicine.
The study's time period was before the CT scanner was installed at Dunstan in 2013, which might account for a much larger disparity in Dunstan and Queenstown.
CT rates for city dwellers were 14% higher than for rural patients in areas including Gore, Balclutha, and Western Southland.
They were 63% higher than patients in Queenstown and Dunstan.
Installed in 2008, the CT scanner in Oamaru was the second in a rural hospital in New Zealand.
The scanning rate for Oamaru residents almost doubled after the scanner was installed.
By 2010, the community had the highest scanning rate in the region, 1.2 times that of Dunedin.
By 2011 and 2012, rates were on par with those in Dunedin.
''The sharp rise in scanning rates and then levelling off suggest that the high rates seen in the first two years were the result of pent-up demand and not an indication of long-term over-servicing,'' Dr Nixon said.
When contacted, Mr Gonzales agreed, saying the spike simply reflected a large backlog of patients waiting for a scan.
Mr Gonzales said Oamaru Hospital had taken a close interest in the research, because of perceptions about its use of the scanner.
''We want to be able to allay concerns that we might be over-servicing our population.''
That rates were on par with Dunedin showed the value of locating scanners in rural areas.
''This is something that is quite significant to take note of. The local availability of a CT scanner really does make a difference in terms of primary access to diagnostic procedures.''
Over-use of CT scanners is potentially concerning because of the radiation dose received by patients.
