THE RELEVANCE OF DICOM-RT IN RADIOTHERAPY

INFORMATION SYSTEMS

Preliminary Results from a National Survey

Celeste Marques Oliveira

1,2,3

and Pedro Pereira Rodrigues

1,4

Faculty of Medicine of the University of Porto, Al. Prof. Hernâni Monteiro, 4200-319 Porto, Portugal

Faculty of Sciences of the University of Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal

Department of Radiotherapy, Portuguese Oncology Institute Francisco Gentil

Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal

LIAAD - INESC TEC & CINTESIS - Center for Research in Health Technologies and Information Systems

University of Porto, Porto, Portugal

Key

words: DICOM-RT, Radiotherapy, Information system, Interoperability.

Abstract: Currently, in radiotherapy (RT) departments, there are different manufacturers and stand-alone information

systems (IS) for single-purpose applications. These systems have most of the data distributed through

different IS. The DICOM-RT extension has six objects that provide a standardized way of transferring the

information circulating in the external beam RT. The aim of this study is to assess expert’s opinion about

DICOM-RT and IS interoperability in the RT context, through the characterization of Portuguese RT

facilities, in terms of equipment and IS with the identification of existing interoperability problems. This

study is cross-sectional, and the preliminary results presented in this paper are relative to the period May-

July 2011. All Portuguese RT departments (i.e. 20) were invited to cooperate in the survey; the response

rate was 40% (n=8), while 10% (n=2) of the institutions did not authorize the RT departments to participate.

The preliminary results show that the RT departments have some equipment and IS from different vendors

contributing for heterogeneity of RT workflows. The experts somehow attribute importance to

interoperability, but have low knowledge about their own IS integrations, and DICOM-RT. Compliance

with DICOM-RT is recommended when acquiring new RT IS to optimise the interoperability.

1 INTRODUCTION

In modern medicine, one of the most technologically

advanced fields is radiotherapy (RT), which is, after

surgery, the most successfully treatment modality

used for cancer (Schlegel et al., 2006). About 60%

of patients with cancer, will require RT during the

course of their illness and those who are cured, 80-

90% of the patients underwent RT (Perez and Brady,

1998).

RT is probably the earliest example of computer

programming application to the solution of clinical

treatment decision problems (Kalet, 2008). It is an

interdisciplinary field, based on physics, radiation

biology, mathematics, computer science, electrical

and mechanical engineering. Increasing

sophistication in computer-assisted treatment

planning and delivery has improved the accuracy

and distribution of radiation dose in patient leading

to a significant increase of tumor control and the

consequent probability of cure (Schlegel et al.,

2006); (Levitt et al., 2008).

1.1 Problem Setting

Currently, in RT departments, where the treatments

are based in the most technological advancements in

diagnostic imaging, image processing and high

computerization technology, such as the treatment

planning systems (TPS), there is an increase of the

complexity of storage and availability of RT data.

Often there are different manufacturers and stand-

alone information systems (IS) for single-purpose

applications (Liu et al., 2007); (Law et al., 2009).

These multiple IS, focused on the system instead of

being patient-centered, acquire the necessary

information during the RT treatment course, being

131

Marques Oliveira C. and Pereira Rodrigues P..

THE RELEVANCE OF DICOM-RT IN RADIOTHERAPY INFORMATION SYSTEMS - Preliminary Results from a National Survey.

DOI: 10.5220/0003711201310136

In Proceedings of the International Conference on Health Informatics (HEALTHINF-2012), pages 131-136

ISBN: 978-989-8425-88-1

 2012 SCITEPRESS (Science and Technology Publications, Lda.)

most of the data distributed through each IS. This

data isn’t immediately available due to

incompatibles formats between the equipment

workstations and the IS. This lack of interoperability

between the IS causes discontinuity in health care,

leading to redundant clinical evaluations and clinical

decisions based on incomplete information limiting

clinical trials and scientific investigations (Law,

2005).

Some attempts by collaborative groups to

improve workflow and integrate IS through the

standardization of data exchange formats, resulted in

two relevant formats in RT. The standard used by

North American Radiation Therapy Oncology Group

(RTOG) - format RTOG based on report nr. 10 of

the American Association of Physicists in Medicine

(AAPM), which was designed for the purpose of

transferring RT data to the Radiotherapy and

Oncology Group data centre so that quality

assurance of clinical trials could be performed. And

the standard digital imaging and communications in

medicine version 3.0 (DICOM v3.0) with the RT

extensions designated DICOM-RT resulted from the

working group 7 of the committee formed from

members of American College of Radiology (ACR)

and the National Electrical Manufactures

Association (NEMA) (Schlegel et al., 2006);

(Huang, 2010).

1.2 DICOM-RT Description

The DICOM-RT extension consists of six objects for

the external beam RT, which provide a standardized

way of transferring much of the information

circulating in the RT workflow. The six DICOM-RT

objects are (Dicom Standards Committee, 1997);

(Dicom Standards Committee, 1999):



RT Structure Set-

defines a set of structures of

significance in RT related to patient anatomy,

markers and isocenters;



RT Plan-

contains geometric and dosimetric data

specifying a course of treatment, including treatment

beam parameters (e.g field sizes, beam orientations

and modifiers), patient setup, fractionation

scheme,etc;



RT Dose-

includes the dose data generated by

TPS in various formats (e.g. 3-D distribution of

radiation dose, isodose curves, dose points);



RT Image-

specifies the attributes of RT images

that are “acquired or calculated on a conical imaging

geometry” giving additional information.



RT Beams Treatment Record-

treatment

session records during a RT treatment course.



RT Treatment Summary Record -

treatment

summaries indicating the cumulative state of a

treatment course.

1.3 DICOM-RT Benefits

The benefits of using DICOM-RT can be (Law and

Huang, 2003); (Law and Liu, 2009):



Transmission of the textual information and

images between IS of different vendors with

minimal effort from users providing communication

between isolated IS.



Full integration of IS with technologies from

different vendors helping save time and effort spent

in searching and minimize the loss of records and

images.



Monitoring and analysis of the RT workflow.



Integration of the treatment process into an

electronic patient record (ePR).



Platform for information sharing with hospital

information systems (HIS) and other IS allowing

cross-center clinical research and expert

consultation.



Development of decision support tools and a

knowledge base in the medical imaging informatics

research through the patient outcomes.

1.4 Aim

The purpose of this study is to know the RT expert’s

opinion about the DICOM compliance, the DICOM-

RT objects utilization and the interoperability

existing in the IS of Portuguese RT departments,

with the collection of data about treatment

equipment, imaging modalities and IS.

2 METHODS

A cross-sectional approach was used to achieve the

proposed target.

2.1 Study Participants

The target population of this study are all RT

departments in Portugal (i.e. 20). About 60% of

institutions are private hospitals and 30% of

departments belong to university hospitals or cancer

centers. In the scope of this study it was just

considered the facilities of external beam RT. All

RT departments which have agreed to participate

have been included in the present study.

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2.2 Design Study

This is a cross-sectional survey representing the

reality found in these RT departments, and the

preliminary results presented in this paper are

relative to the period May-July 2011.

2.3 Questionnaire

A structured questionnaire with five groups,

identified in Table 1, was created using expert

opinion.

Table 1: Structure of the questionnaire “DICOM-RT in the

radiotherapy information systems”.

Group Title

I Profile of the respondents

II Characterization of the RT department

- Survey of technological resources

- Survey of imaging modalities

- Survey of IS

III Characterization of picture archiving and

communication system (PACS)

IV Characterization of IS and the DICOM utilization

V Opinion about interoperability

The construction of questions of group II relative

to the survey of technological resources was based

on results from the Portuguese governmental

document “Development strategy for the

development of radiotherapy in Portugal for the next

decade” (Pereira et al., 2008), where it is described a

national survey of equipments and staff in all RT

facilities, and in some articles of national surveys

from other countries (Owen et al., 1997); (Wigg and

Morgan, 2001); (Teshima et al., 2008); (Jefferies et

al., 2009). The other groups were based on the

books: “PACS and imaging informatics: basic

principles and applications” (Huang, 2010) and

“Handbook of radiotherapy physics: theory and

practice” (Mayles et al., 2007). The questions of

group V, concerning the opinion about

interoperability, were constructed with positive

sentences using Likert scales (Mcdowell, 2006).

The questionnaire was constructed aiming to be

adapted to the Portuguese reality and was reviewed

by three experts (one medical physicist, one

radiation therapist, and one professor of

radiotherapy) that suggested some changes that were

made. The questionnaire was created with the web

technologie MedQuest (Gomes, 2009).

2.4 Data Collection

All the chiefs of RT departments were informed

about the survey and cooperation was asked to send

the questionnaire to the chief information officer or

the head of medical physics or the manager of

radiation therapist. For some institutions, a

requirement for authorization to conduct the survey

was requested and sent to the administrative councils

or ethics committee or research office. After their

support and multiple telephone calls with the

participants, an e-mail was sent to each department

with the URL of the questionnaire addressed to the

experts.

2.5 Variables Description

The main variables of the questionnaire can be

grouped into the reality existing inside the RT

departments and expert’s opinions.

2.5.1 Variables about RT National Survey

 Which existing techniques of external beam RT;

 Quantification of the staff;

 Which existing equipment of RT (commercial

designation, manufacturer, installation year):

 Treatment machines;

 Simulation equipments;

 Imaging equipments.

 Which IS exist RT (commercial designation,

manufacturer, version):

 TPS;

 Imaging systems;

 Record and Verify (R&V) systems;

 PACS:

 Which interfaces;

 Which functions;

 Compliance with DICOM v3.0.

2.5.2 Variables about DICOM-RT Expert’s

Opinion

 Profile of the respondent:

 Age group, sex;

 Academic qualification, professional

experience and position;

 If know DICOM standard (level of

knowledge);

 If know DICOM-RT extension (level of

knowledge).

 Characterization of IS:

 Compliance with DICOM v3.0;

 Compliance with DICOM-RT;

 Which DICOM-RT objects are in use;

THE RELEVANCE OF DICOM-RT IN RADIOTHERAPY INFORMATION SYSTEMS - Preliminary Results from a

National Survey

133

 Utilization of other communication standards.

 How to describe utilization of DICOM-RT in the

workflow of RT;

 How to describe the IS behaviour;

 When purchasing a new IS for the department, if

the interoperability issue is addressed:

 Which factors are more important;

 Who defines the integration of IS.

 For a good policy is it better one single vendor or

multiple vendors;

 Which procedures are more important, to achieve

IS interoperability with the DICOM-RT;

 Which factors are more important, for the

immaturity of the DICOM-RT implementation;

 Which benefits of DICOM-RT are more

important;

 If there are any interoperability problems

between the IS:

 If yes, identify the existing interoperability

problems, specifying the IS participants.

The data obtained from the questionnaires was

exported by MedQuest to the IBM® SPSS®

software version 19 for statistical analysis.

3 RESULTS

Until July 20 the response rate was 40% (n=8),

while 10% (n=2) of the institutions did not authorize

the RT departments to cooperate in the survey. The

institutions that answered the questionnaire are

widely separated geographically and of varying

departmental size (facilities with only 1 treatment

unit to 8 treatment units). The number of RT

professionals per institution varies between 9 and

68, with a median of 14.5. Per RT department, the

radiation oncologists with a median of 3.5, the

medical physicists with a median of 3, and the

radiation therapists with a median of 9. The nursing

staff, the assistants and the clerks were not

considered.

3.1 RT National Survey

All of the RT departments have 3-D conformal RT,

and 37% have intensity modulated RT. In terms of

treatment machines, all of the facilities have

exclusively linear accelerators with the median

installation year 1997, rather than cobalt units and

orthovoltage. 50% of the departments are multiple-

treatment units, and of these, only one department

has machines from different manufacturers.

Relatively to simulation, 50% have this equipment

and the other 50% have virtual simulation. The

simulators come from two vendors and the virtual

simulation comes from other three vendors.

Concerning imaging, the vast majority of the centers

(75%) have computed tomography (CT) department,

and only one department has a dedicated magnetic

resonance imaging (MRI) for RT planning purposes.

All this imaging equipment comes from three

vendors. All the departments use digital image,

including image registration carried out between

planning CT and MRI or positron emission

tomography. For the image guidance, all of the

institutions have portal images with megavoltage

and 37% with kilovoltage.

Regarding IS, all the departments have at least

one TPS and one institution has three systems from

different vendors. Imaging systems are from three

different vendors. About R&V systems, in

departments with single-treatment unit, this system

is from the same vendor of treatment machine. In

departments with multiple-treatment units, the R&V

system is from the same vendor of one of treatment

machine. Several departments (37%) have PACS,

which have interface with TC workstation, TPS,

simulator workstation and R&V systems, having as

mainly functions: storage, image reception, and

database update.

In terms of distribution of suppliers by country of

origin, Germany is the country with the highest

expression (43%), followed by United States of

America (29%), Sweden (14%) and Netherlands

(14%).

3.2 DICOM-RT Expert’s Opinion

The respondents were mainly medical physicists,

with a mean experience of 10,5 years, being 63%

Head of Medical Physics. All the participants knew

the DICOM standard and the RT extensions, and

63% of those consider their level of knowledge as

reasonable.

According to 63% of participants, RT IS are

DICOM-RT compliant. Although the RT plan and

RT structure set are implemented in all departments,

the RT dose is only in seven departments, and the

RT image and RT beam treatment record are only in

six departments. According the same 63% of

respondents, the imaging systems are in

conformance with DICOM v3.0 too. The use of

other communication standards is referred by 37%

of participants, but the only standard identified was

health level 7 (HL7).

Respecting expert opinion, 50% of respondents

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consider that the utilization of RT objects in the RT

workflow is very good, and the remaining thinks that

is good or reasonable. The behaviour of the IS,

according to most of the participants, is

interoperable because they integrate information

from different IS vendors.

When purchasing a new IS for the department,

75% respondents think that the interoperability issue

is addressed; the others have no knowledge about it.

The vast majority believes that the important factors,

by order of importance, in this issue are: 1st existing

IS integration problems, 2nd

IS need, 3rd

interoperability problems in the workflow, 4th

context of purchasing. The integration of the new IS

in the workflow, is commonly defined by the vendor

together with the informatics and the medical

physicist.

For a good policy, most experts assume that the

more sophisticated equipments and flexibility of IS

for the integration in multi-vendor context are more

important compared with context of one single

vendor. To achieve SI interoperability, with the

DICOM-RT, the procedures considered more

important are: replacement of analogue by digital

image, determination of workflows, frequent

updating versions of SI. The three most frequently

mentioned reasons to justify the immaturity of the

DICOM-RT implementation are: 1st inexistence of

DICOM-based database, 2nd lack of strategic

management of the department, 3rd low compliance

to standard by suppliers. Regarding DICOM-RT

benefits the experts classified by the following order

of importance: 1st transfer of information between

different IS vendors, 2nd integration of RT

technologies in IS multi-vendor context, 3rd

integration into the ePR, 4th communication with

other institutions, 5th communication with other

specialties, 6th workflow monitoring, 7th support for

computer-assisted decision, 8th helpful in clinical

research, 9th assistance for the knowledge base

creation.

For the open question about the existence of

interoperability problems between the IS of the RT

department, only two participants assume that have

problems. One specified that the problem lies in the

interface between the R&V system with three HIS.

The other identified that the problem is based on the

fact of having many different suppliers in the

department.

4 DISCUSSION

Currently in the RT departments, the question of

interoperability is considered as crucial for

achieving gains, by improving the quality and

continuity of care, allowing cost reduction by

minimizing repeated procedures or exams,

improvements in research, decision support, among

many others.

In RT context more important that achieve

connectivity “plug and exchange” between two

systems is to accomplish application interoperability

“plug and play”. The complexity of interoperability

in RT is greater compared with the radiology.

A limitation of this study is the inexistence of

other similar studies for comparison. It was found

national surveys of RT (Alto Comissariado Da

Saúde, 2008) but only focusing in the workforce,

workloads and equipment. None of none of them

focuses on IS, DICOM-RT and interoperability.

These preliminary results show that the RT

departments have some equipment and IS from

different vendors contributing for heterogeneity of

RT workflows. The experts somehow attribute

importance to interoperability, but have low

knowledge about their own IS and respective

integrations. The same happens about the

familiarity with DICOM, DICOM-RT and other

communication standards; in the questions about the

conformance with the DICOM v3.0 and DICOM-

RT, there are a significant percentage of respondents

that answered “I have no knowledge”.

Essential for the RT departments’ cooperation

has been the issue of confidentiality and anonymity

of participants. The data collection, in the majority

of the cases, was hard. This may be over due to the

lack of documentation regarding existing IS and

their integrations.

This survey has assessed the current status of RT

technologies and IS. This characterization is helpful

to understand the real RT workflows of each

department. The expert’s opinion about

interoperability and DICOM-RT reveals that they

trust in the standard but with lack of specific

information about this issue.

The questionnaire aimed to explore issues that

could help departments to optimise their IS in the

RT workflow. But as the participants think that have

no interoperability problems and those who think

that have, didn’t detailed with enough information.

Therefore, only general recommendations can be

suggested. Experts of this study believe in the

benefits of integration between the IS and

equipments but with few knowledge about this

pertinent issue. Information that can be drawn from

these opinions is that the RT professionals don’t

have sufficient training on issues such as: DICOM-

THE RELEVANCE OF DICOM-RT IN RADIOTHERAPY INFORMATION SYSTEMS - Preliminary Results from a

National Survey

135

RT, application interoperability, other

communication standards, etc.

General recommendations for RT professionals

to achieve or optimize the interoperability at the RT

departments:

 When purchasing a new IS for RT department

request a IS compliant with DICOM-RT with all RT

objects available.

 When purchasing new equipment for RT

department only buy a machine in conformance with

DICOM v3.0.

 When implementing the new device DICOM

conformant, specification and testing of the clinical

application capabilities and data flow needs to be

performed by the RT facility to ensure effective

integration.

 For a good policy in RT department, the strategy

must focus on reliable computer applications with a

high degree of built-in connectivity.

 Use the PACS model in the RT department,

whether departmental or institutional, with the

DICOM v3.0 and DICOM-RT.

 It is important to adapt the existing RT

workflows to those publicised by

integrating the healthcare enterprise (IHE) (I.H.E.,

2011) integration profiles and technical frameworks

providing a common platform to use DICOM and

HL7.

The implementation of these recommendations will

be essential to optimise the interoperability in the

RT context.

ACKNOWLEDGEMENTS

The authors acknowledge the RT departments that

participated in the study, the contribution provided

by the RT experts (António Gonçalves, Luís Cunha,

Ana Barros) and the help afforded by Jorge Gomes

in the MedQuest utilization.

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