Radiation Passport aims to fulfill an important need: to quantify the cancer risk for the various diagnostic imaging studies and to add up the cumulative exposure and cancer risk for one patient. The app makers explicitly invite lay persons to track their own cumulative dose (thus the monicker “passport”) but the design and vocabulary appear to be targeted more toward physicians.

While the diagnostic benefits of modern imaging techniques are easily appreciated, the risk of exposure to ionizing radiation is less well understood. This question has become more acute as recently published studies attempting to quantify cancer risk from diagnostic radiation were widely picked up by media outlets. I can attest that, in recent months, many of my patients have brought up this coverage when I ordered scans. At the same time, I have also decreased orders for CT scans and even x-rays in my pediatric patients.

Radiation Passport (iTunes link) was designed and built by a team of two brothers, one of whom is a radiologist – and is priced at $3.99. The application includes a well written “background” section which deals early-on with the vexing dilemma of calculating cancer risk – that much of of the data on cancer risk is extrapolated from atomic bomb data – by simply stating it is the best information available. Much of the background section of the app is drawn from an accompanying article in the Journal of American College of Radiology, in which the brothers describe the application’s methodology.
risk comparison graph

What is not controversial is that usage of diagnostic imaging has increased dramatically over the last two decades. For example, in the background section of the app, it quotes an article stating that the number of CT scans performed has doubled every two years since the mid 1980s. Another quoted article (Brenner and Hall, 2007) apparently claims that up to 1.5-2% of ALL cancers in the US may become attributable to radiation from CT scans alone, if current usage rates continue. These numbers make it clear that mitigating this risk is an increasingly important goal for patients and physicians alike.

The application has two main functions. One is a straightforward “calculator” of radiation exposure. Studies are sorted into categories such as “cardiology”, “dental”, “GI”, “CT”, etc. The other is a personal repository of cumulative radiation exposure. The application takes into account the age of the patient and the age at the time of radiation exposure. This is important since radiation induced cancers usually take many years to develop and therefore, exposure at young age is considered higher risk than later in life. The app automatically enters the average amount of radiation exposure for each type of study (in milli-Sieverts), although this default can be overridden.
risk pie chart

Once the studies have been entered, the app displays a pie chart of the different modalities’ contribution to cumulative lifetime radiation exposure and cancer risk. It is interesting to see that background earth radiation is actually a large proportion to the cumulative dose, that is until one gets a few CT scans under the belt !

What I liked about this app:

  • it addresses an important need for physicians and patients
  • it is well referenced and thoughtfully designed
  • provides rich functionality, both in the range of parameters that can be entered and the types of studies and also in ways the resulting risk can be displayed

What I thought could be improved

  • the application navigation is somewhat confusing, in particular the cumulative dose information and the individual study information are in the same view while the dose & risk information are separated across two application tabs
  • it would seem more logical to separate the cumulative dose and individual study information apart into two tabs while keeping dose and risk information for studies vs. patients together
  • background settings

  • if lay person use is to be encouraged (which I agree is very useful), extensive purging is needed of as much medical jargon as possible from the app, especially in study selection controls
  • it would also be helpful to have a few prompts on first launch to guide the user, rather than just showing a blank list
  • the slider switch for list vs. graph display is too small and often results in inadvertent pressing of the nearby “background” tab
  • it would be helpful to have a “duplicate” feature for studies entered into personal repository since many patients are on a regular surveillance schedule and repeatedly undergo a set of studies over many years (it is nice that adding a new study at least duplicates the last one entered)
  • chest-abdomen-pelvis CT is missing as an option
  • the ability to send emails and view web pages could easily be incorporated into the app instead of requiring quitting the application
  • finally, the name “Radiation Passport” is a slightly confusing since a passport is primarily used for entry across borders, while this app is more of a log or journal
  • Conclusion

    background information
    Radiation Passport is a very well thought-out application that addresses an important need. It is well documented and comes at a time of increasing attention to the cancer risk of diagnostic imaging by physicians and patients. In order to achieve its potential the application interface should be streamlined and the confusing use of medical jargon mitigated to allow for better usage by lay persons.

    Tidal Pool Software (www.tidalpool.ca), the makers of Radiation Passport, has announced a partnership with Clario Imaging to integrate their dose and risk cumulative logging functions directly into Clario zVision radiology and picture archiving information system (RIS/PACS). This will be helpful for physicians to inform them, at the point of order entry, the cumulative dose and risk for their patients.