Advanced Validation

Overview

In this section, we go through a few checkpoints through a system administrator's lens, to ensure the system is functional and correctly configured.

Server Validation

Now we SSH to the server as ec2-user, as instructed above. Once connected, we can check cloud init log:

sudo tail -F /var/log/cloud-init-output.log

In the log, each container should say Orthanc has started. The configuration files related to Orthanc deployment are in directory /home/ec2-user/orthanc-config. Refer to the orthanc-config repository for how the configuration automation works.

DICOM communication (TLS)

To emulate DICOM activity, we use dcmtk, with TLS options. We use the echoscu executable to issue C-ECHO DIMSE command, and the storescu executable to issue C-STORE commands. For example:

echoscu -aet TESTER -aec ORTHANC -d +tls client.key client.crt -rc +cf ca.crt ec2-35-183-66-248.ca-central-1.compute.amazonaws.com 11112

The files client.key, client.crt and ca.crt can all be obtained from the /tmp/ directory on the server.

The output should read Status code 0 in C-ECHO-RSP, followed by C-ECHO-RQ. Here is an example of the output from storescu:

I: Association Accepted (Max Send PDV: 16372)
I: Sending Echo Request (MsgID 1)
D: DcmDataset::read() TransferSyntax="Little Endian Implicit"
I: Received Echo Response (Success)
I: Releasing Association

Further, we can store some DICOM part 10 file (usually .dcm extension containing images) to Orthanc server, using storescu executable:

storescu -aet TESTER -aec ORTHANC -d +tls client.key client.crt -rc +cf ca.crt ec2-35-183-66-248.ca-central-1.compute.amazonaws.com 11112 DICOM_Images/COVID/56364823.dcm

Below is an example of what the output from storescu should look like:

D: ===================== OUTGOING DIMSE MESSAGE ====================
D: Message Type                  : C-STORE RQ
D: Message ID                    : 427
D: Affected SOP Class UID        : CTImageStorage
D: Affected SOP Instance UID     : 1.3.6.1.4.1.9590.100.1.2.227776817313443872620744441692571990763
D: Data Set                      : present
D: Priority                      : medium
D: ======================= END DIMSE MESSAGE =======================
D: DcmDataset::read() TransferSyntax="Little Endian Implicit"
I: Received Store Response
D: ===================== INCOMING DIMSE MESSAGE ====================
D: Message Type                  : C-STORE RSP
D: Presentation Context ID       : 41
D: Message ID Being Responded To : 427
D: Affected SOP Class UID        : CTImageStorage
D: Affected SOP Instance UID     : 1.3.6.1.4.1.9590.100.1.2.227776817313443872620744441692571990763
D: Data Set                      : none
D: DIMSE Status                  : 0x0000: Success
D: ======================= END DIMSE MESSAGE =======================
I: Releasing Association

C-STORE-RSP status 0 indicates successful image transfer, and the image should viewable from the Orthanc site address.

DICOM communication (without TLS)

Caution: turn off TLS only if the images are transferred over private connection or encrypted connection. Refer to device connectivity for how to set up.

To turn off TLS, locate the server configuration in the nginx configuration file for DICOM port, and remove the SSL options. For exmaple, here is what the snippet looks like with TLS encryption:

stream {
    server {
        listen                11112 ssl;
        proxy_pass            orthanc-service:4242;
        ssl_certificate       /usr/local/nginx/conf/site.pem;
        ssl_certificate_key   /usr/local/nginx/conf/site.pem;
        ssl_protocols         SSLv3 TLSv1 TLSv1.2 TLSv1.3;
        ssl_ciphers           HIGH:!aNULL:!MD5:ECDH+AESGCM;
        ssl_session_cache     shared:SSL:20m;
        ssl_session_timeout   4h;
        ssl_handshake_timeout 30s;
    }
}

Here is what it looks like after removing TLS encryption:

stream {
    server {
        listen                11112;
        proxy_pass            orthanc-service:4242;
    }
}

When using dcmtk utility for DICOM Ping or C-STORE, also remove the arguments related to tls.