Operational Concepts In

A Deployed Radiology Suite

Services Rendered

P.A.C.S.

Plain film and wet processing are a thing of the past in a deployed setting.  All of your images will be digital (computed radiography) and moving them around may be problematic.  Many of the sites will have a small DICOM printer on hand but some do not.  How then, do you send images to the E.D. physician or forward them to the next echelon of care?

The answer lies in digital transmission of images.  Each deployed unit will have an in-house computer network.  The imaging department is equiped with desktop computers to accommodate image acquisition, manipulation, and storage.  Each of the patient care areas will have a notebook computer with somewhat lower screen resolution.  An ideal network allows the technologist to acquire images in the radiology suite and network them to several locations.  The radiologist should have a reading area that is independent of the image acquisition area and access to word processing software to create radiologic reports.  In addition, your technologist should train the professional staff to retrieve images from the network and view them remotely.  Some sites have failed to implement the internal network in radiology at the expense of technologist productivity.  If providers and radiologists are reading from the image acquisition station, the technologist is not free to move on with other patient care.

This internal image network is relatively easy to accomplish.  There are no firewalls to overcome and the local systems office can help you establish the DICOM settings in your network profiles.  However, the on-site computer technicians are rarely medical imagers and they do not always have experience with DICOM imaging.  There are some things you can tell them that will help.  First; explain the problem in computer lingo.  Here are some definitions they will need:

         DICOM – Digital Imaging and Communications in Medicine

         AE Title – Application Entity Title, used to identify the DICOM nodes communicating between each other.  AE titles are case sensitive!!

         PACS- Picture Archive Communication System

Next, select the DICOM software you are going to use.  Each EMEDS comes with viewing software but it may be worth your time to review alternative sources.  Your CR reader will have DICOM software installed and may include licenses for on-site workstations.

Now that images are flowing internally, you need to decide how to move images to a remote location.  There are three options:

1.      Digital Transmission

2.      Hard Copy

3.      Digital images on CD ROM

Digital transmission via teleradiology is the most cost efficient and timely method of moving images between medical treatment facilities.  Unfortunately, it is also the most difficult method to establish.  Each military network is protected by firewalls that do not like DICOM transmissions.  Your deployed systems technicians will have to work with a central firewall administrator at Shaw AFB to configure the network settings.  The firewall administrator will need to know the IP address and transmission port of the originating system as well as the receiving system.  They will manually configure the firewalls at both bases to allow point-to-point communication between the two computers.  That’s the hard part!  Firewall administrators just don’t like to open ports in their networks.  Once the firewalls are open, you can send and receive images in near real time.  Configuring your system to send images to a remote location is exactly the same as setting it up for the E.D. or the O.R.  There are no additional settings for leaving the base.

Each software vendor configures the port settings differently, but they are all in DICOM format.  This means that you can send images from a Picker CT scanner to a Kodak workstation or a GE PACS without worry.  Check the software CD for a users manual.  All of the DICOM settings should be included in the manual.  You may also find the following links helpful:

A detailed explanation of system requirements

A primer on diagnostic imaging PACS configuration

Medical Physics

Expeditionary medical units are often pre-deployed and operational when you arrive.  However, it is entirely possible that you will arrive at a bare bones base and be expected to direct the deployment of your radiology equipment.  In either circumstance, the placement of your equipment will have a substantial impact on the operations and safety of the entire facility.  A good first step is to consult with the on site bioenvironmental officer and your deploying technologists.  Great care must go into proper placement to ensure the best possible radiation practices while addressing operational concerns of the other professional staff members.

Experience has shown that the radiology tent should be placed on an outside perimeter of the medical “facility” with a healthy space outside of the tent.  Ensure that the upright film stand is placed on an outside wall and the x-ray generator is pointed away from patients and staff when in operation.  This will reduce unintended radiation exposure to the hospital staff and their patients.

Once the equipment is deployed, the bioenvironmental officer will conduct a radiation survey of the site.  This should be accomplished before operations begin and whenever significant structural/equipment changes occur.  The site survey will identify areas around your equipment that exceed acceptable radiation levels during operations.  It is your responsibility to ensure the areas are cordoned off and appropriate warning signs are posted while radiation is present. 

The standard radiation symbol is the three-bladed design. Specifically, the crosshatched area is to be magenta, purple, or black, in a yellow background. Additional information to the contents of signs and labels may be provided to make individuals aware of potential radiation exposures.

1.      Portable X-Ray equipment:

o        Follow the principles of time, distance, and shielding

o        Always wear your lead apron when working around any portable x-ray equipment

o        Remain at least 6 feet away when doing portable x-rays

o        Beam orientation: Careful orientation of the beam is essential while performing oblique and lateral films so the CR will not inadvertently expose others.

o        Holding patients: Is permissible only after all options have been exhausted. Every effort should be made to have someone other than the x-ray technologist hold the patient or film. Anyone holding patients must wear lead aprons and lead gloves and be positioned so that no part of their body is exposed to the central ray. Pregnant females or persons under 18 years old are NOT PERMITTED to hold patients.

o        TLD's should always be worn.

o        Mobile equipment: The operator should avoid getting exposed to the central ray. Always wear your lead apron. Be aware of the orientation of the central ray and remain at least six feet from the tube during the exposure.

2.      X-Ray Rooms:

o        While x-rays are being performed everyone should leave the room except for the technologist, patient, or doctor (if needed).

o        Remain behind the portable shielding during exposure.

o        You should not routinely hold films during exposures.  If you are asked to hold the film make sure you are wearing a lead apron, and not in the direct path of the central ray. 

3.      Fluoroscopy:

o        During portable fluoroscopy (C-Arm), everyone should leave the room except the x-ray technologist, physician, and any other personnel required for the procedure.

o        Always wear your lead apron and maintain as much distance as possible while fluoro is on.

o        Protect others and repeat "Fluoro On" when you begin Fluoro.

o        kVp, mA relationship: Skin dose increases proportionally to the tube current (mA). X-Ray production and penetrability is also proportional to the tube voltage potential (kVp). Exposure to low dose rates are best achieved using high kVp and low mA settings.

o        Source to Image distance (SID): Always maximize the SID (as practical) and avoid any physical contact with the port on the tube. Some units are provided with spacers such as plastic cones and other devices. These spacers are designed to limit the tube to patient distance, removing the spacer creates a potentially dangerous situation and is NOT recommended.

o        X-Ray tube position: Under the table tube location is highly recommended. This tube orientation minimizes the amount of scatter radiation and consequently helps to minimize exposure to the operator.

o        Image intensifier to patient distance: Minimize the image intensifier to patient distance.  This reduces scatter radiation being emitted from the patient. In addition, the patient dose will be reduced as the image intensifier is positioned closer to the patient.

o        Image magnification: Minimize the use of this optional feature. Minimizing this feature will also help reduce the patient exposure.

o        Grid: This device helps to improve the overall image quality (contrast) by means of shielding the image intensifier from scattered X-Rays. Using the grid will increase the radiation exposure to the patient.  If the grid is removed, a reduction in exposure by a factor of two is possible at the expense of image quality.

o        Collimation: Collimate as tightly as practical to minimize patient exposure and carcinogenic risks. Collimation reduces scattered radiation and the volume of tissue exposed.

o        Beam ON Time: Patient exposure is directly related to beam on time which should be kept to a minimum. Any beam-on time in excess of 30 minutes should be documented in the patient's record.

o        Patient's History: Carefully review the patient's record for any evidence of multiple procedures involving ionizing radiation. Inspect the skin for possible evidence of radiation damage like, telangiectases, epidermal thinning, dermal atrophy, or skin pigment changes. Slight angulation may help minimize further damage to already affected areas.

o        TLD's: Individual exposure and collective exposure readings is one of the most effective ways of evaluating the radiation risks in your work area.