Open research protocol
A prespecified national study of how far Australians live by road from registered X-ray, ultrasound, CT, MRI, nuclear medicine and PET practices.
This page contains methods, not findings. The destination audit, population inputs and road-network analysis will be frozen before any result is added. Empty charts and illustrative values are deliberately absent.
Research question
How far is the scan people need?
Among people living in Australia, what is potential geographic access by road to registered diagnostic-imaging locations, separately for each major modality, at a frozen study date?
The study measures registered physical proximity. It does not measure appointments, waiting time, scanner or workforce capacity, affordability, clinical eligibility, service quality, utilisation or health outcomes.
Figure 1
From population grid to access estimates
The study is a cross-sectional ecological spatial-access analysis. Every input and transformation will be versioned so the published numbers can be reproduced.
Population origins
Populated one-kilometre 2021 ABS Population Grid cells, with Mesh Blocks for classifications and a sensitivity analysis.
Imaging destinations
A dated LSPN-derived inventory, deduplicated into physical practices and independently audited by modality, jurisdiction and remoteness.
Road routing
A frozen OpenStreetMap extract and routing-engine profile. Failed routes stay missing; straight-line distance never silently replaces them.
Access outcomes
Nearest, second and third site; travel-time distributions; provider choice; and stratification by remoteness, IRSD and jurisdiction.
Table 1
Outcomes fixed before analysis
Thresholds are descriptive reporting bands, not definitions of adequate access.
| Outcome family | Measures | Reported for |
|---|---|---|
| Nearest physical site | Road time and distance; population-weighted median, 75th and 90th percentiles | Each modality nationally and by remoteness, IRSD and jurisdiction |
| Descriptive access bands | Population within 15, 30, 60 and 120 minutes | Each modality, with denominator and missing routes |
| Alternative physical sites | Time to the second and third site; time penalty from first to second | Each modality |
| Provider choice | Physical sites and distinct provider groups within 30, 60 and 120 minutes | Each modality; unknown ownership remains unknown |
| Conditional MRI analysis | Road time to a location on the dated government MRI-location list | Only if linkage validation succeeds; never presented as a rebate guarantee |
Table 2
What earlier Australian studies answer—and what they do not
The contribution is deliberately narrow. Earlier work already covers national imaging use, regional cardiac-imaging utilisation, mammography clinic access and national BreastScreen drive times.
| Source | What it measured | Remaining question |
|---|---|---|
| Lu et al., 2024 | National Medicare-funded imaging utilisation, 2000–2021 | Did not measure clinic locations or patient road access |
| Fonseca et al., 2015 | Regional variation in reimbursed outpatient cardiac imaging across Medicare Locals | Utilisation is not branch-level physical access |
| Hyndman and Holman, 2000 | Population-weighted road distance to seven mammography clinics in metropolitan Perth | Not national, current or multi-modality |
| AIHW, 2024 | National drive time to permanent and visiting BreastScreen services | Screening mammography is not general diagnostic imaging |
| Filipcikova et al., 2026 | National road travel to hospitals, emergency departments, GPs and pharmacies | Radiology practices and imaging modalities were not included |
| This protocol | Contemporary registered non-screening practices, national population origins and six modalities | Potential geographic access only—not realised access, capacity, cost or quality |
Publication plan
Figures and tables that will carry the findings
The completed report will pair accessible web figures with vector publication exports and downloadable aggregate data. Every value will come from the same frozen result table.
- Six aligned national access mapsOne shared travel-time legend across X-ray, ultrasound, CT, MRI, nuclear medicine and PET.
- Cumulative population access curvesThe share of Australians within each road-time threshold, with missing routes shown.
- Remoteness and IRSD gradientsWeighted medians, tails and access bands without disguising ecological limits.
- Alternative-site and provider-choice gapsHow much farther the second physical site or distinct provider group is.
- Destination validation tableRaw records, physical sites, audited errors and uncertainty by modality.
- Reproducible sensitivity figureThe effect of deduplication, origin, route and uncertain-destination decisions.
No result graphic will be published until its source table, caption, accessible summary and downloadable CSV all agree.
Cite this protocol
This permanent URL identifies the public protocol. The version and date make clear that it precedes the outcome analysis.
Verified full texts
References used on this page
- Lu P, Mian M, Yii M, et al. Rising use of diagnostic imaging in Australia: An analysis of Medicare-funded radiology services between 2000 and 2021. J Med Imaging Radiat Oncol. 2024;68:50–56. doi:10.1111/1754-9485.13591
- Fonseca R, Otahal P, Wiggins N, Marwick TH. Growth and geographical variation in the use of cardiac imaging in Australia. Intern Med J. 2015;45:1115–1127. doi:10.1111/imj.12867
- Hyndman JCG, Holman CDJ. Differential effects on socioeconomic groups of modelling the location of mammography screening clinics using Geographic Information Systems. Aust N Z J Public Health. 2000;24:281–286. doi:10.1111/j.1467-842X.2000.tb01569.x
- Australian Institute of Health and Welfare. Access to BreastScreen Australia screening services. Canberra: AIHW; 2024. Cat. no. CAN 158. Report
- Filipcikova M, Jorm L, Barbieri S. Travel times and distances to health services in Australia. Sci Data. 2026. doi:10.1038/s41597-025-06381-y
- Wood SM, Alston L, Beks H, et al. The application of spatial measures to analyse health service accessibility in Australia: a systematic review and recommendations for future practice. BMC Health Serv Res. 2023;23:330. doi:10.1186/s12913-023-09342-6