DICOM Anonymization

DICOM Anonymization

DICOM (Digital Imaging and Communications in Medicine) files contain sensitive patient information that must be protected when sharing medical imaging data. Anonymization ensures that personally identifiable information (PII) is removed or modified while maintaining the integrity of the medical images.

Aspose.Medical.Dicom.Anonymization provides an API to anonymize DICOM files using predefined confidentiality profiles, ensuring compliance with privacy regulations such as HIPAA and GDPR.

Anonymizing a DICOM File (Basic Usage)

You can anonymize DICOM files in a few simple steps. The Aspose.Medical.Dicom.Anonymization.Anonymizer.Anonymize method removes or redacts sensitive patient and study information while preserving the structure of the DICOM dataset. To anonymize a DICOM file, please follow the steps below:

  1. Load an existing DICOM file using DicomFile.Open.
  2. Create an anonymizer instance (Aspose.Medical.Dicom.Anonymization.Anonymizer) with default settings.
  3. Use anonymizer.Anonymize(dicomFile) to remove sensitive attributes.
  4. Save the anonymized file for further use.
// Load a DICOM file
Aspose.Medical.Dicom.DicomFile dicomFile = DicomFile.Open("input.dcm");

// Create an anonymizer with the default profile
Aspose.Medical.Dicom.Anonymization.Anonymizer anonymizer = new();

// Anonymize the DICOM file
Aspose.Medical.Dicom.DicomFile anonymizedFile = anonymizer.Anonymize(dicomFile);

// Save the anonymized file
anonymizedFile.Save("anonymized_output.dcm");

Anonymization Profiles

Anonymization profiles allow customized redaction of DICOM metadata based on predefined rules. Profiles define how specific metadata fields should be handled. A confidentiality profile helps control what information gets anonymized or retained. The library supports loading profiles from various formats (CSV, JSON, XML).

To anonymize a DICOM file using a predefined specific Confidential Profile, please follow the steps below:

  1. Initializes the anonymization profile using ConfidentialityProfile.CreateDefault method with the specific options, e.g., ConfidentialityProfileOptions.CleanGraph.
  2. Create an anonymizer instance (Aspose.Medical.Dicom.Anonymization.Anonymizer) with these options.
  3. Use anonymizer.Anonymize(dicomFile) to remove sensitive attributes.
  4. Save the anonymized file for further use.
// Create a default confidentiality profile with basic anonymization rules
Aspose.Medical.Dicom.Anonymization.ConfidentialityProfile profile = ConfidentialityProfile.CreateDefault(ConfidentialityProfileOptions.CleanGraph);

// Create anonymizer using this profile
Aspose.Medical.Dicom.Anonymization.Anonymizer anonymizer = new(profile);

// Load a DICOM dataset
Aspose.Medical.Dicom.DicomFile dicomFile = DicomFile.Open("input.dcm");

// Anonymize the dataset using the profile
Aspose.Medical.Dicom.DicomFile anonymizedFile = anonymizer.Anonymize(dicomFile);

// Save result
anonymizedFile.Save("anonymized_output.dcm");

Confidentiality Profile options described in DICOM PS 3.15: https://dicom.nema.org/medical/dicom/current/output/chtml/part15/chapter_E.html#table_E.1-1 The relation between Aspose.Medical profiles and the ones defined in DICOM PS3.15:

  • BasicProfile - Basic Profile. XML/JSON column name is basic_profile.
  • RetainSafePrivate - Retain Safe Private Option Profile. XML/JSON column name is rtn_safe_priv_opt.
  • RetainUIDs - Retain UIDs Option Profile. XML/JSON column name is rtn_uids_opt.
  • RetainDeviceIdent - Retain Device Ident Option Profile. XML/JSON column name is rtn_dev_id_opt.
  • RetainInstitutionIdent - Retain Institution Ident Option Profile. XML/JSON column name is rtn_inst_id_opt.
  • RetainPatientChars - Retain Patient Chars Option Profile. XML/JSON column name is rtn_pat_chars_opt.
  • RetainLongFullDates - Retain Long Full Dates Option Profile. XML/JSON column name is rtn_long_full_dates_opt.
  • RetainLongModifDates - Retain Long Modif Dates Option Profile. XML/JSON column name is rtn_long_modif_dates_opt.
  • CleanDesc - Clean Desc Option Profile. XML/JSON column name is clean_desc_opt.
  • CleanStructdCont - Clean Structd Cont Option Profile. XML/JSON column name is clean_struct_cont_opt.
  • CleanGraph - Clean Graph Option Profile. XML/JSON column name is clean_graph_opt.

There is a virtual option All that is the union of all the listed options.

Confidentiality actions determine how sensitive data is processed.

  • D - Remove the data completely;
  • Z - Replace the value with a zero-length string;
  • X - Replace value with dummy data;
  • K - Keep the value unchanged;
  • C - Replace with a coded phrase;
  • U - Replace with universally unique identifier (UID).

Custom Anonymization Profiles

Aspose.Medical supports custom anonymization profiles that can be loaded from JSON, XML, CSV files.

Loading Custom Profiles from CSV

A CSV file can define anonymization rules for specific DICOM tags.

CSV Structure Example:

TagPattern;Action
0010,0010;Z  // Anonymize PatientName
0010,0020;D  // Remove PatientID
0020,000D;U  // Replace StudyInstanceUID

To load a profile from CSV file, please use the following code snippet:

// Load confidentiality profile from a CSV file
Aspose.Medical.Dicom.Anonymization.ConfidentialityProfile profile = ConfidentialityProfile.LoadFromCsvFile("profile.csv", ConfidentialityProfileOptions.All);

// Create anonymizer with custom profile
Aspose.Medical.Dicom.Anonymization.Anonymizer anonymizer = new(profile);

Loading Custom Profiles from JSON

A JSON file can define anonymization rules for specific DICOM tags.

JSON Structure Example:

[
    { "Tag": "0010,0010", "Action": "Z" },
    { "Tag": "0010,0020", "Action": "D" },
    { "Tag": "0020,000D", "Action": "U" }
]

To load a profile from JSON file, please use the following code snippet:

// Load confidentiality profile from a JSON file
Aspose.Medical.Dicom.Anonymization.ConfidentialityProfile profile = ConfidentialityProfile.LoadFromJsonFile("profile.json", ConfidentialityProfileOptions.All);

// Create anonymizer with custom profile
Aspose.Medical.Dicom.Anonymization.Anonymizer anonymizer = new(profile);

Loading Custom Profiles from XML

XML file can define anonymization rules for specific DICOM tags.

XML Structure Example:

<root>
  <item>
    <tag>0010,0010</tag>
    <action>Z</action>
  </item>
  <item>
    <tag>0010,0020</tag>
    <action>D</action>
  </item>
</root>

To load a profile from XML file, please use the following code snippet:

// Load confidentiality profile from an XML file
Aspose.Medical.Dicom.Anonymization.ConfidentialityProfile profile = ConfidentialityProfile.LoadFromXmlFile("profile.xml", ConfidentialityProfileOptions.All);

// Create an anonymizer with the custom profile
Aspose.Medical.Dicom.Anonymization.Anonymizer anonymizer = new(profile);

Advanced Anonymization

Certain scenarios require more control over how sensitive data is altered. You can manually specify how sensitive information (like patient names and IDs) should be replaced. To anonymize a DICOM file using custom settings for PatientName and PatientID tags, please follow the steps below:

  1. Initialize a new instance of the Aspose.Medical.Dicom.Anonymization.ConfidentialityProfile that replaces the PatientName and PatientId.
  2. Applying this profile anonymizes files while keeping certain identifiers intact.
  3. Save the anonymized file for further use.
// Load a DICOM file
Aspose.Medical.Dicom.DicomFile dicomFile = DicomFile.Open("input.dcm");

// Create a confidentiality profile and set custom values
Aspose.Medical.Dicom.Anonymization.ConfidentialityProfile profile = new()
{
    PatientName = "ANONYMOUS PATIENT",
    PatientId = "00000000"
};

// Create an anonymizer with this profile
Aspose.Medical.Dicom.Anonymization.Anonymizer anonymizer = new(profile);

// Anonymize the file
DicomFile anonymizedFile = anonymizer.Anonymize(dicomFile);

// Save the anonymized file
anonymizedFile.Save("custom_anonymized.dcm");

In-Place Anonymization

Instead of generating a new file, you may want to modify the DICOM file directly.To anonymize a DICOM file without generating a new file, please follow the steps below:

  1. Load an existing DICOM file using Aspose.Medical.Dicom.DicomFile.Open.
  2. Create an anonymizer instance (Aspose.Medical.Dicom.Anonymization.Anonymizer) with default settings.
  3. Use anonymizer.AnonymizeInPlace(dicomFile) to remove sensitive attributes.
  4. Save the anonymized file for further use.
// Load a DICOM file
Aspose.Medical.Dicom.DicomFile dicomFile = DicomFile.Open("input.dcm");

// Create anonymizer
Aspose.Medical.Dicom.Anonymization.Anonymizer anonymizer = new();

// Perform in-place anonymization
anonymizer.AnonymizeInPlace(dicomFile);

// Save the modified file
dicomFile.Save("inplace_anonymized.dcm");
Transcoding DICOM file DICOM Error Handling and Exceptions