Mobile X-ray for TB prevalence studies and outreach screening

A (semi-)mobile diagnostic TB container commonly consists of an X-ray and reception room, batteries, inverters, solar panels and/or a portable power generator, UV light, air-conditioning and a complete work station. At this station patient data can be entered and images can be read and stored digitally; all integrated in a lead shielded 20 foot container for easy transport by a standard truck. A mini-lab in the container allows for microscopy and/or GeneXpert machines.

Fit for easy & safe Transport: As a standard sized 20 foot container, the unit is transportable by any truck locally available and is optimised for large scale prevalence studies or systematic screening programs in high risk groups such as people living in overcrowded areas, prisoners, mineworkers, PLWH etc. With a sophisticated - yet simple to operate - lifting device, the relatively low weight container is off-loaded from the truck and the X-ray system can be up and running in less than 1.5 hours. The truck is normally not integrated in the mobile unit, so the unit can after the prevalence survey is completed for instance be operational in a fixed setting for TB screening at a prison site, mine or hospital.

Energy supply: With the latest technology in batteries and inverters, the single phase (220 V) X-ray unit is capable of making, storing and sending approximately 200 images without the need for external power. Solar panels on the roof or a portable power generator that can be stored in the container can also be used to generate energy at remote sites. A refrigerator, climate control or a fan can be integrated in the container.

The reception room contains the diagnostic viewer and PC and is separated from the camera room by led protected walls and door. The X-ray room contains the digital X-ray system that is fixed in the container floor.

Solar panel truck

Impression of a solar powered TB screening unit

CIDRZ based in Lusaka, Zambia operates the mobile "One Stop TB" container concept with a (single phase) Direct Digital Radiographic system and a small laboratory for TB prevalence surveys in high risk groups, like inmates. This diagnostic container was awarded in 2010 a grant under the WHO TB Reach call for innovative TB case detection proposals and ranked in 2011 first place on the impact analysis (presentation at UNION Conference in Lille 2011).

The NTP of Rwanda operates a 2 compartment diagnostic container with Direct Digital X-ray to support its TB prevalence survey. A central archive and PACS software allows the NTP of Rwanda to forward all digital Chest X-rays including participant data over the mobile phone network as one compacted electronic file to a central database in Kigali for second reading and back-up. Data transmission per participant over the mobile phone network typically take 35 seconds. Similar operational experience was reported from Ghana.

In an innovative TB project co-funded by the Governments of Ghana and the Netherlands the Ghana Health Service/NTP implemented a nationwide tele-radiology network with 50 solar powered digital X-ray systems of which 2 are used in vans for outreach TB screening services (see below picture). The TB case detection rate in Ghana at the time the project implementation started - June 2016 - was estimated by WHO at 32% only. This project - including eHealth innovations such as CAD4TB - is expected to empower the NTP of Dr Bonsu in more effectively finding the missing TB cases nationwide in support of the END TB Strategy.

The NTP of Malawi has with Global Fund support since March 2018 7 “one Stop TB” screening units operational for active case finding using dCXR/CAD as rapid triage before Xpert MTB/RIF. On average about 100 people are being screened for active TB per day per unit (see picture below) with, based on the first results, a high yield of finding the missing cases of which most never visited a health facility for their illness. As next steps in the services to be provided by these “fast track” mobile screening units Malawi considers to integrate HIV counseling and testing services (Training, Supplies of HIV test kits, reporting and recording tool, screening for hypertension and diabetes and targeting other towns and hot spot areas in the country. These solar powered screening units are considered an essential and high impact intervention in support of the END TB Strategy in Malawi.

Wellness on Wheels (WoW) truck - used in Nigeria in support of finding the missing people with TB - includes: digital X-Ray/CAD and GeneXpert, to bring high-quality “one Stop TB” diagnosis directly to densely populated areas.

Occupational health screening with digital chest X-ray and CAD in South Africa

The Zero TB Initiative (ZTBI) is working across the world to create islands of elimination with strong local partners in high-burden areas. Screening for presumptive TB cases in e.g. Pakistan is done by IRD with support from mobile digital X-ray and CAD as a rapid triage before Xpert MTB/RIF with a high impact on case notification.

Portable X-ray systems

"Also lower cost portable digital X-ray systems are available for reaching the most remote areas with digital radiology. These systems can be transported in the back of for instance a SUV like a Landcruiser or Landrover. Images taken in remote locations where mobile phone network is available can be sent instantly to the central database in for instance the capital city”. Batteries can be incorporated in the SUV to enable self sufficient power supply in the field. The MRC of The Gambia, the NTPs of Kenya, Zimbabwe and Ghana operated these using portable dCXR systems for the TB prevalence survey. Also as a result of smart image compacting software up to 300 digital X-rays per day could be made, viewed and stored with one system without the need for consumables.

These portable digital X-ray systems for medical use are to be specifically designed for use in areas with high ambient temperatures and eleva­ted humidity like Africa or South East Asia. Such systems come with a more powerful (6-8kW) X-ray generator, allowing for high daily throughput and quality X-ray images at the lowest possible patient dose by minimizing exposure time. Since this year also a very compact portable system is available on the market that can be carried in a back-pack and operates reliably on batteries.

To avoid having to adjust both the X-ray tube and the detector for every different patient height, both columns with tube and detector can be height synchronized and motor driven. Such construction and a 6-8 kW X-ray tube are critical for high productivity in the field and avoidance of overheating of the X-ray generator. Foldability of aluminum columns allow for easy transportation in any 4x4 using roller wheels and sturdy flight cases.