Offline Studies

Introduced by : Mohammadnour Alzaareer

Hospital Workflow – Radiology

HIS

RIS\PACS

EHR

Radiology Workflow

Requesting / Appointment

Imaging

Reporting and Image

Distribution

Workflow in radiology department

Admitted Patient Dataflow:- Visit referring Physician.

-Order for Radiology Procedure.-Patient arrived to Radiology Reception Desk.-Create of Radiology Request for immediate exam.-Create of Appointment for planned exams.-Study request sending to modality through DICOM W/L-Patient Arrived .-Patient examined, study send to archive node (PACS).-New exams store action into Short Term Storage (STS).

HIS-RIS-PACS

What is PACS?

P : picture, images and reports.

A: archiving; online, near line ,offline.

C: communication, networking , transfer protocol.

S: system infrastructure , components

architecture.

PACS Storage Levels

Short Term Storage (STS) Online Caches. Online Storage. Fast Access storage.

Near Line Storage /Archive (NLS/A) Archive of STS. Reasonable retrieve access/speed. DR (Disaster Recovery)

PACS Storage Levels

Long Term Storage (LTS) Online or Offline media. Tapes / DVD’s / Blue Ray DVD’s (if it is ISO certified). Output of NLS/A. User intervention needed for offline media

( Challenge)

PACS Storage Hardware

1. STS ( Online caches): DAS (Direct Attached Storage). NAS (Network Attached Storage). SAN (Storage Area Network).

2. NLS/A ( Near Line caches): NAS (Network Attached Storage). SAN (Storage Area Network). Tape Library (LTO3/LTO4/LTO5/…) Medical CD/DVD Archive ( Juke Box).

3. LTS ( Could be Online / Offline): Tape Library (LTO3/LTO4/LTO5/…) Medical CD/DVD Archive .

STS & NLS Storage size parameters

STS (Online Caches):- Site / Hospital size (No. of Beds).-Number of DICOM Modalities.-Type of Modalities (CT/MRI/X-Ray/Mammogram).-Number of Exams per modality per day.-Growth factor.NLS/A(Near-line Caches):-STS storage size.-Number of daily archive and growth factor.-Requested retrievals speed /time

PACS Standard Requirements

1. The standard recommendation for Radiology exams storage coverage period on STS is 5 years.

2. For NLS/A computation should cover at least double of STS period.

3. LTS will be dependent on the used hardware and media capacity … it could be online (Automated retrievals ) or offline ( system admin intervention is required).

Field example / Study

- Site : King Hussein Medical Centre (KHMC) .- STS (SAN) Size : Coverage of 5 years. (24.4 TB Net DICOM storage).-NLS/A (Tape Library) : Net of 67.0 TB (168 Tapes)-LTS (Tapes) : 100 Offline and 68 online.

Online Tapes are fully automated (read / write)

Offline Tapes , System Admin intervention is needed when requested.

When to request LTS on Offline

- For long term patient treatments.-For staged studies comparisons.-CA patients & Follow up.-Legal cases assessment and tracking.-Research / keyword.

For all the above ,,, time and automation is of high importance.

Theoretical aspects

The Theoretically solution is to increase the size of storage for multi Terabyte's but this will increase the cost of the system, and the new Terabyte’s will filled in data again.

and because of rarely needs of offline images; we have to find a suitable way to make them available when needed at a glance such as online image .

Suggestions & proposed solutions

1. NLS/A archives storage size increment (Cost).2. STS Storage size increment (Cost & Capacity

limitation).3. Activation of patient study priors over the night

one day before visit date based on day appointment list. By that all needed exams will be transferred automatically from LTS to NLS then to STS and the Radiologist will have seamless interpretation on the level of retrieval time and speed.

4. Implement new storage technologies like storage clouds or VNA’s

Thank you