# Cybersecurity and Medical Imaging: A Simulation-Based Approach to DICOM Communication
## 5 Simulation Results and Analysis
### Setting Up Orthanc to Accept Data from the Modality Simulator
\begin{split}\text{\sc{MODALITY}}\xrightarrow{\text{\sc{P-DATA, Command ID=1 (Success)}}}PACS\quad\text{at time $T_{9}$}\end{split}  \tag{11}\]

**P-DATA, C-STORE-RQ I. ** The P-DATA message is used to transfer DICOM data between the MODALITY and Orthanc entities; in this case, it is a C-STORE request (C-STORE-RQ) sent by MODALITY to Orthanc. Here, _\"ID=1\"_ indicates that this is the first C-STORE request in the communication session. This request (Listing 12) includes information about the data to be stored, such as the DICOM object or image. A C-STORE request (C-STORE-RQ) is a DICOM message used to request the storage of DICOM objects, such as medical images, in a destination device or system. It contains information about the object to be stored, including its unique identifier and transfer syntax; C-STORE-RQ enables the standardized and reliable transfer of DICOM objects in healthcare environments. **P-DATA, X-ray Angiog (reassembled fragment). ** This message (Listing 12) represents a fragment of the X-ray Angiographic Image Storage data. The message continues as long as the transmission of the X-ray Angiographic Image Storage data continues, and is reassembled in a final P-DATA network packet. This signifies that the data transmission is ongoing and more fragments are being sent to complete the image or object. **PDATA, Command ID=1 (Success). ** This message (Listing 12) represents a complete DICOM P-DATA message containing the entire X-ray Angiographic Image Storage. It indicates that the data transmission for this particular object or image is complete. #### 5.4.4 Association Termination

To conclude the communication, MODALITY initiates the termination process by sending an A-RELEASE request to Orthanc at time \(T_{10}\), as expressed in Equation (12). \[ \begin{split}\text{\sc{MODALITY}}\xrightarrow{\text{\sc{A-RELEASE request}}}PACS\quad\text{at time $T_{10}$}\end{split}  \tag{12}\]

PACS responds by acknowledging the request with an A-RELEASE response, which is received by MODALITY at time \(T_{11}\), as presented in Equation (13). \[ \begin{split}\text{\sc{MODALITY}}\xrightarrow{\text{\sc{A-RELEASE response}}}PACS\quad\text{at time $T_{11}$}\end{split}  \tag{13}\]

**A-RELEASE Request. ** The A-RELEASE request is sent by MODALITY to initiate the termination (Listing 13) of the DICOM association between MODALITY and Orthanc. This indicates the intention to close the connection gracefully. A-RELEASE is a message used in the DICOM protocol to initiate the termination of a DICOM association between two devices or systems. The A-RELEASE message is sent by one entity to the other to indicate an intention to gracefully close the connection. Upon receiving the A-RELEASE message, the recipient entity acknowledges the request by sending an A-RELEASE response. The A-RELEASE process allows for the orderly termination of the DICOM association, ensuring the proper release of resources and connections associated with the session. This is an essential step in maintaining the integrity and efficiency of DICOM communication between devices or systems in healthcare environments. **A-RELEASE Response. ** The A-RELEASE response is sent by Orthanc in response to the A-RELEASE request from MODALITY. It acknowledges the termination request and signifies the successful termination of the DICOM association. ### Discussion

The simulated environment for DICOM communication serves as a platform for testing and addressing essential aspects of network security and related cybersecurity issues. The environment is designed to replicate DICOM communication scenarios, and facilitates a comprehensive understanding of potential threats as well as the actions needed to mitigate them. DICOM communication is susceptible to several cyberthreats, and the presented simulation can assist in conducting security assessments as well as in implementation and testing of mitigation actions in an isolated and realistic environment. Cyberthreats selected as important can be replicated within the simulation, including the following:

1.