{ brain-pain:de } P-RDSR

Patient Radiation Dose Structured Report (P‑RDSR)

Executive summary

The Patient Radiation Dose Structured Report (P‑RDSR) is a DICOM Structured Report (SR) object and associated set of templates designed to encode estimated patient and organ doses, together with the underlying methodology, for ionizing radiation procedures such as CT, projection X‑ray, and radiopharmaceutical administrations. P‑RDSR complements, rather than replaces, the existing Radiation Dose Structured Report (RDSR), which primarily captures equipment‑reported output metrics (e.g., CTDIvol, DLP, DAP) and irradiation geometry.

P‑RDSR has been standardized as DICOM Supplement 191, finalized in 2017 and incorporated into the main DICOM Standard, particularly PS3.3 (Information Object Definitions) and PS3.16 (Content Mapping Resource, templates TID 10030–10034). Clinical and vendor adoption is ongoing and currently concentrated in radiation dose management systems and research settings, with broader deployment expected as regulatory and professional requirements for patient‑specific dosimetry continue to evolve.

1. General explanation of the importance of P‑RDSR

1.1 Motivation: from equipment output to patient dose

Existing DICOM dose mechanisms such as the RDSR encode detailed information about irradiation events, including tube potential, exposure parameters, geometry, and summary metrics like CTDIvol, DLP, and DAP. These objects describe the radiation output of the equipment and basic procedural context, but they do not encode the resulting absorbed or equivalent dose to patient organs or tissues.

As dose management practices matured, it became clear that a standardized way to store patient‑specific dose estimates—not just equipment output—was needed. Multiple methodologies and models (Monte‑Carlo, analytical models, anatomical or stylized phantoms, voxel phantoms) can derive organ doses from RDSR data, but prior to P‑RDSR there was no DICOM object dedicated to persisting these results along with information about the models and assumptions used.

1.2 Scope and clinical relevance

P‑RDSR is intended to record estimates of radiation dose to a patient from diagnostic and interventional CT, projection X‑ray, and radiopharmaceutical administrations, both diagnostic and therapeutic. Occupational exposure and dose from external beam therapy, ion beam therapy, and brachytherapy are explicitly out of scope because those domains are addressed by other DICOM IODs (e.g., RT Dose) and regulatory frameworks.

By encoding organ‑specific absorbed or equivalent doses and associated uncertainties, P‑RDSR enables several clinically and regulatory relevant use cases: longitudinal tracking of cumulative dose to radiosensitive organs, population‑level dose registries, optimization and justification analyses, and support for patient‑specific risk communication. Because P‑RDSR can aggregate contributions from multiple modalities and procedures, it also supports more complete patient dose assessments over an episode of care or across the patient’s imaging history.

1.3 Relation to body structures and anatomical context

A key design goal of P‑RDSR is to relate dose not merely to study‑level metrics but to specific organs and anatomical regions. The central template TID 10031 “Radiation Dose Estimate” defines content items for organ dose estimates, including coded identification of each organ, the type of dose metric (e.g., mean absorbed dose, maximum skin dose), and the numerical value and units.

In addition, TID 10032 “Radiation Dose Estimate Representation” allows linking dose estimates to spatial representations such as surface segmentation IODs (e.g., skin dose maps) or parametric maps, as well as point clouds representing dose distributions within the patient. This design enables mapping dose estimates onto patient images or computational models, which is essential for organ‑level risk estimation and visual analysis of dose distributions in complex interventional procedures.

2. Key differences between P‑RDSR and RDSR

2.1 Conceptual roles

RDSR and P‑RDSR occupy complementary positions in the DICOM ecosystem:

• RDSR captures what the equipment did during irradiation events—output metrics, technique factors, and geometry—sufficient to reconstruct or estimate dose but not the dose estimates themselves.
• P‑RDSR captures the estimated dose to the patient (organs, whole body, phantoms) and the methodology used, using RDSR or other sources as inputs.

This separation avoids duplication of raw technique data while allowing independent workflows for image management, output logging, and dose estimation and reporting.

2.2 Structural and template differences

Both RDSR and P‑RDSR are realized as DICOM SR IODs, but they are based on distinct template families:

• RDSR uses modality‑specific templates such as TID 10001 (Projection X‑Ray Radiation Dose), TID 10011/10012 (Irradiation Event Data), and CT dose templates.
• P‑RDSR introduces a new family of templates (TID 10030–10034) specifically for patient dose estimation and reporting.

Key P‑RDSR templates include:

• TID 10030 – Patient Radiation Dose: Root container aggregating patient dose estimates from one or more sources of radiation.

• TID 10031 – Radiation Dose Estimate: Contains individual organ or whole‑body dose estimates, specifying organ, dose quantity (absorbed or equivalent), metric type (mean, max, etc.), uncertainty, and reference conditions.

• TID 10032 – Radiation Dose Estimate Representation: Links estimates to spatial models or images, e.g., skin dose maps encoded as surface segmentation or parametric maps

• TID 10033 – Radiation Dose Estimate Methodology: Encodes the calculation method, including references to RDSR instances, model assumptions, phantom types, Monte‑Carlo codes, and input parameter selections.

• TID 10034 – Radiation Dose Estimate Context (procedure phase): Associates dose estimates and methodology with specific procedure phases that share common estimation parameters.

These templates together allow P‑RDSR to represent not only numerical dose values but also the provenance and spatial context of those values.

2.3 Dose content and metrics

The RDSR content is restricted to quantities describing equipment output and simple derived metrics such as CTDIvol, DLP, and DAP, along with accumulated values per series or study. RDSR does not include patient‑specific organ dose values or effective dose; any such quantities must be computed externally.

In contrast, P‑RDSR explicitly encodes organ doses and related metrics:

• Only absorbed dose and equivalent dose are allowed dose quantity types, in line with radiation protection concepts.
• A single value per organ per estimate is required, with a coded attribute indicating whether this value represents, for example, mean organ dose, maximum, minimum, or another metric.
• Whole‑body or phantom doses can be recorded for quality control or simplified estimation scenarios.[^6]

Optional support exists for expressing uncertainty, reference conditions, and links to models, which are crucial for interpreting and comparing dose estimates derived using different methods.

2.4 Relation to anatomical structures and spatial mapping

RDSR can encode the imaged anatomical region using coded entries for body parts (e.g., “Abdomen”, “Chest”) and procedure type, but it does not natively support organ dose distributions or spatial dose maps.

P‑RDSR, by contrast, is explicitly designed to relate dose to organs and, where available, to mapped anatomical structures and dose distributions: organ codes, references to segmentation objects, and registration information allow dose estimates to be overlaid on specific anatomical models or patient images. This makes P‑RDSR the key vehicle for moving from study‑level dose metrics to organ‑level and regional dose assessment.

2.5 Workflow and actor differences

RDSR instances are typically generated automatically by imaging modalities at the time of acquisition and transferred to PACS, RIS, or dedicated dose management systems. P‑RDSR instances, in contrast, are usually created by a “Dose Information Reporter” or similar actor, which may be a standalone dose management system, a PACS/RIS component, or a specialized dosimetry workstation.

The P‑RDSR design deliberately decouples dose estimation from image acquisition, allowing dose estimation to occur asynchronously, potentially using updated models, patient habitus information, or cross‑modality data, and then recorded as a separate SR object that references the original RDSR and related imaging objects.

3. Status of the current P‑RDSR standard and implementation

3.1 Standardization status in DICOM

The concept of a dedicated Patient Radiation Dose SR arose from the recognition that none of the existing non‑image DICOM objects (RDSR, MPPS, header) provided a template for persistent patient‑specific dose estimates. A DICOM working item (2012‑11‑C) tasked WG‑28 (Physics), in collaboration with WG‑02 and other groups, to develop a Patient Dose SR, including support for skin dose mapping.

This work resulted in DICOM Supplement 191 “Patient Radiation Dose Structured Report (P‑RDSR)”, which defines a new SR object and SOP Class for patient dose reporting. The supplement’s final text was approved in May 2017, and its content has since been integrated into the main DICOM Standard (e.g., PS3.3 for the Patient Radiation Dose SR IOD and PS3.16 for templates TID 10030–10034).

The DICOM standard’s public description confirms that P‑RDSR “adds support for creating a structured report to contain the information concerning the recording of the estimated radiation dose to a patient,” covering CT, projection X‑ray, and radiopharmaceutical administration, while excluding occupational and radiotherapy dose

3.2 Relationship to other DICOM dose standards

P‑RDSR complements existing RDSR templates for X‑ray and CT dose reporting, which remain the primary mechanism for recording equipment output and per‑event dose metrics. Informative annexes in PS3.17 continue to describe the use of RDSR for radiation dose reporting, explicitly excluding radiopharmaceutical and patient dose SRs, which are documented separately.

In addition, DICOM working groups have coordinated with IEC projects (e.g., IEC PT 61910‑1) and IHE profiles (notably IHE Radiation Exposure Monitoring, REM) to ensure consistency between DICOM dose reporting objects (including P‑RDSR) and external standards and integration profiles.

3.3 Implementation and deployment status

Published literature and professional reports indicate that RDSR is widely used as the primary standardized input for radiation dose management systems (DMS) in CT and X‑ray, allowing automated collection and analysis of dose‑related parameters. These systems support optimization, DRL compliance, and quality assurance workflows and rely heavily on RDSR for accurate and structured dose data.

For P‑RDSR, adoption is more recent and currently less ubiquitous than RDSR. The AAPM newsletter announced P‑RDSR as part of the DICOM standard and highlighted its template structure and use for organ dose estimates and dose representation objects. Initial implementations are reported mainly in research and advanced clinical environments, where organ‑dose modeling (for example using Monte‑Carlo or hybrid computational phantoms) is integrated with DMS or dosimetry workstations that can produce P‑RDSR objects.

There is limited publicly available quantitative data on how many commercial systems fully implement P‑RDSR, and uptake appears heterogeneous across vendors and regions. Nonetheless, ongoing interest in patient‑specific dosimetry within the radiology and medical physics communities, as reflected in standards and EuroSafe Imaging recommendations, suggests that P‑RDSR support will expand as organ‑dose estimation becomes a routine expectation in dose management.

3.4 Ongoing and future work items

DICOM working group materials list ongoing goals to ensure consistency between DICOM dose reporting objects and IEC specifications, to monitor and align with IHE Dose Reporting profiles, and to extend dose reporting capabilities for skin dose in interventional procedures. WG‑02 and WG‑28 hold joint meetings to refine the structure of Patient Dose SR, indicating that P‑RDSR is expected to evolve as new clinical requirements and modeling techniques emerge.

Potential areas for future refinement include improved support for:

• Detailed skin dose maps for complex interventional procedures.
• Harmonized coding of organ definitions and anatomical regions (e.g., alignment with SNOMED CT and ICRP reference organs).
• Representation of uncertainties and model validation data.
• Aggregation of multi‑modality dose contributions at the patient level over long time spans.

These directions are consistent with the flexible, extensible nature of the P‑RDSR template family.

4. Estimated completion and official introduction

4.1 Standardization milestones

From a standards perspective, P‑RDSR can already be considered “completed” in the sense that Supplement 191 reached Final Text status in 2017 and has been incorporated into the current DICOM Standard editions. The DICOM web description of P‑RDSR confirms its role as the object for recording estimated patient radiation dose, alongside existing RDSR objects.

Accordingly, there is no separate, pending “official introduction” date; P‑RDSR became part of the normative DICOM standard when Supplement 191 was integrated (e.g., PS3.16 2017c and subsequent releases). Any further changes will occur through the usual DICOM change proposal (CP) or supplemental processes and will be versioned as part of future standard revisions.

4.2 Implementation and adoption timelines

While the standard is stable, the practical “completion” of P‑RDSR in clinical practice depends on vendor implementation and institutional deployment. Radiation dose management systems are already widely deployed and rely heavily on RDSR, and they form the natural technical foundation for P‑RDSR support. However, organ‑dose estimation requires additional modeling capabilities, patient‑specific data, and validation, which slows uniform adoption compared to simpler RDSR logging.

Published recommendations from European and international initiatives emphasize the importance of robust dose management, including organ and patient dose assessment, but they do not mandate a specific DICOM object or timeline for P‑RDSR adoption. As a result, broader uptake of P‑RDSR is expected to be gradual and driven by a combination of regulatory developments, professional guidelines, and the maturation of commercial and open‑source dosimetry solutions.

4.3 Outlook for future evolution

Given the extensible structure of the P‑RDSR templates and ongoing WG‑02/WG‑28 activities, P‑RDSR should be viewed as a stable yet evolving framework for patient dose reporting rather than a one‑off, frozen specification. Future change proposals may refine organ coding, uncertainty representation, and spatial mapping capabilities as clinical and research communities gain experience with large‑scale organ‑dose data.

In the medium term, it is reasonable to expect that P‑RDSR, together with RDSR and related standards, will become the backbone for integrated patient dose registries and advanced dose analytics, enabling more accurate organ‑specific risk assessment and optimization across imaging modalities. The timing and extent of this evolution will depend on active collaboration between modality vendors, DMS providers, and medical physics and radiology stakeholders.