Whole-Body Counting Systems

Whole-Body Counting

Reliable Results for Critical Data . . .

chair1.jpg (45873 bytes) Whether it is an upgrade to your current system or a completely new installation, rely on ORTEC systems for your Whole-Body Counting needs.

As a leading supplier of Whole-Body Counting (WBC) systems, ORTEC engineers continue to develop new techniques, solve new problems, and provide the best data results and handling capabilities on detector instrumentation. ORTEC systems are built upon a solid, technical foundation providing a variety of measurement technologies, software options, and complete solutions for every analysis need.

NaI Systems
The ORTEC StandFAST^Ž II is the industry leader in detection capability. The StandFAST II has a remarkably large interior dimension compared to other counter systems.

standfast.jpg (157237 bytes) The large 4" x 4" x 16" NaI(Tl) detectors in the center column of the StandFAST II give an ideal geometry and high efficiency for a walk-through counter. The combination of large detectors with superior shield design ensure very low detection capability (see Table 1).

The StandFAST II system includes detectors, electronics, a computer with Windows^Ž 2000/XP, and RENAISSANCE^Ž1 analysis software. The single cable connection from the detectors to the electronics provides ease of installation, service, and maintenance. The entire system, including the shield, is modular for installation and easy maintenance. The use of the standard PC for data acquisition allows for low lifetime maintenance fees.

An alternative to the stand-up counter is the whole-body chairs. They are a popular alternative due to their small size, comfortable arrangement, and reproducible geometry. A variety of chairs using NaI detectors are in common use chair2.jpg (53065 bytes) throughout the nuclear industry. This ORTEC model uses a single, large (5" x 4") crystal in a collimated shield to provide excellent analysis results.

The swivel chair makes entry and exit of this system easy for the person being counted. The simple design offers many advantages over complex positioning mechanisms. Lower maintenance costs, increased safety, and fixed geometry for calibration and assessment are a few of the features. The large shield and collimator surrounding the detector along with the shadow shield behind the individual being counted deliver low-background capabilities to this unique system design.

chair3.jpg (36596 bytes) HPGe-Based Systems
High-Purity Germanium detector systems offer many advantages over their NaI counter parts which include:

More robust analysis algorithms
Greater stability over long periods of use
Superior identification capabilities for individual nuclide peaks
Advanced peak deconvolution, peak background subtraction, and peak interference corrections

Several styles of the traditional counting chair geometry are available for whole-body counting installations. The system pictured to the right includes the capability to localize the activity to a specific region of the body (stomach vs. lungs). The collimated detector shields provide ideal counting geometry for the region-of-interest. This particular system also incorporates a separate, adjustable NaI detector for thyroid inspection for potential uptakes of radioiodine species.

bed.jpg (45992 bytes) The chair example at the top depicts a general measurement system much like the NaI-based chair shown in the upper right photo. This system combines all the advantages of the NaI system with the improvements offered by the HPGe analysis.

Whole-body counters using bed scanners and fixed position installations are quite common in many facilities. ORTEC detector systems, scanning mechanisms, and bed arrangements are designed for such installations. These types of systems often incorporate a number of HPGe detectors positioned above or below the subject. Putting several detectors in a small space for this type of analysis can be a challenging engineering feat. ORTEC systems have been successfully designed and installed for these applications throughout the world!

The system shown to the right depicts a combination of detectors for localizing potential radioactive contaminants in the body. The two groups of detectors can be moved individually allowing for unique positioning over the subject when necessary. The upper detectors can be located over the lung region or the thyroid (as shown) depending on the analysis being made.

For facilities or locations where liquid nitrogen is unavailable, the ORTEC product line offers mechanical cooling techniques. Today's coolers offer spectacular cooling capacity with little degradation to resolution and peak shape performance. For whole-body counting applications, these are ideal solutions.

Thyroid Counter
ORTEC engineers have specially designed a system for analyzing the uptake of radioiodine in the thyroid.

Each system is integrated and tested at the facility in Oak Ridge, Tennessee, prior to shipment. This ensures plug-and-play use at the customer’s site. The NaI detector is sized to provide optimal efficiency for the 125 I and 131 I isotopes in the human thyroid including a thin, aluminum entrance window for the low-energy photons. The system includes a lead shield/collimator assembly that tilts easily and locks into place. The shield can be angled to make analysis as comfortable as possible for the worker being counted.

The thyroid counting detector can also be incorporated into a whole-body counter arrangement as shown in the HPGe chair geometry.

Specialized HPGe Detectors

ACTINIDE-85
ACTINIDE-85 is a high-resolution, high-purity germanium detector designed specifically for lung burden and whole-body counting applications. The unique detector design allows for the detection of small amounts of actinides such as uranium, plutonium, and americium, as well as higher energy fission products and naturally-occurring radioisotopes, in a distributed source such as the human lung. The detector is based on the PROFILE-FX detector, which employs a proprietary thin entrance window in order to improve low energy efficiency. The ACTINIDE-85 has been optimized to provide high detection efficiency and resolution performance in the energy range of actinides such as Pu, Am and U, which span the 13-200 keV energy range, while the excellent warranted energy resolution at 1.33 MeV means that the ACTINIDE-85 is equally well suited for analysis of fission products as well. It is therefore ideal for monitoring radiation workers - for lung burden, body burden and wounds.

LLD-W
As the leader in HPGe detector technology, the ORTEC research and development team has recently completed work on a new detector for lung-burden applications: the LLD-W. This segmented detector technology is exclusively available only in the ORTEC product line. By combining the advantages of thin LO-AX-51 detectors with those of the ACTINIDE-85, ORTEC engineers have created an ideal detector for lung-burden analysis. Previously, the choice of which detector to use was either a planar or coaxial detector, the planar detector has poor peak-to-Compton and carries high sample-induced background characteristics and the coaxial detector has poor resolution.

No longer is there a need for compromise! The LLD-W minimizes cosmic interference by minimizing its depth (~25 mm) and maximizing the surface area (diameter ł70 mm; area >3850 mm² ) while maintaining excellent peak-to-Compton performance. By performing anticoincidence timing between the front and rear segments, the LLD-W can reduce the background continuum from sample-induced photons by 37% in the region of 5–300 keV.² Because the LLD-W is of N-type coaxial material, this detector offers excellent transmission of low-energy photons (<60 keV) from ALL angles, not just through the front! This is vital for the geometry where (1) the surface area of the lung extends beyond the diameter of the endcap and (2) where ⁴⁰K in other parts of the GI tract, legs, etc., infuences the Compton continuum.

Low-Background WBC Detectors
Whole-body counting with HPGe detectors requires high efficiency, superb resolution, low background, and excellent peak-to-Compton performance. ORTEC's series of GEM, P-type detectors with low background cryostats are ideally suited for this application. The ORTEC line has been manufacturing high efficiency detectors (>120%) for 15 years. Current state of the art is 200% relative efficiency.3 Using these high performance detectors in conjunction with low-background materials and excellent peak shape performance ensures lower detection limits and higher throughput for any WBC system.

² Ratio of suppressed spectrum to unsuppressed spectrum in the energy region of 5-300 keV measurement with ⁶⁰Co source.
³ Measured using the IEEE-325-1996 standard procedure.

phantom.jpg (19912 bytes) Calibration Phantoms
The ORTEC Calibration Phantom is ideally suited for use in a variety of counting systems. The phantom consists of two polyethylene blocks constructed to model the 95% man, a cylindrical block for the thyroid, and an appropriate selection of calibration sources. The sources are chosen based on the type of counter being used (HPGe or NaI) and the energy range of interest. An optional stand is available for placing the calibration phantom in a reproducible geometry in stand-up counters.

The modular design allows the calibration to be tailored for specific applications or areas of research. For instance, to calibrate the response of a chair system to radioactive emissions from the lungs, the operator can simply remove the calibration source from the lower chamber and leave the two sources remaining for the lungs.

RENAISSANCE-32
screen1.jpg (38118 bytes) RENAISSANCE is another software package built upon the ORTEC product lines unique CONNECTIONS-32 architecture. It allows the software to connect to ANY HARDWARE, ANYWHERE on the facility-wide network! With CONNECTIONS-32, there are no limitations to location and specification of hardware for your Whole-Body Counting system. RENAISSANCE uses a simple combination of Supervisor and Operator interfaces. This method separates the duties of the person doing the setup and calibration, from the routine measurement process in a unique and intuitive way. One to four detectors can be used depending on the system.

Upgrading Systems
RENAISSANCE software is also the core component of upgrading Whole-Body Counter systems. Many facilities already have a variety of counting equipment, shields, and detectors. With investments made in a whole-body counter at the time of initial purchase, upgrades need to be as simple and low-cost as possible. RENAISSANCE software is designed to operate not only the new systems being developed today, but also those existing counters already in the facility.

Here are just a few of the reasons for considering an upgrade:

Move to personal computers
Built-in quality assurance
Microsoft Access database output of all results and personnel information
Electronics/detectors need replacement
Robust 32-bit Windows networking support

IMBA Professional Plus now available for Renaissance
The IMBA Professional Plus software supercedes the IMBA Expert software developed for the U.S. Department of Energy, by the Radiation Protection Division of the UK Health Protection Agency (formerly the UK National Radiological Protection Board) and ACJ & Associates, Inc. (Richland, WA, USA).

This software provides a user-friendly interface with the (HPA's) proprietary suite of Integrated Modules for Bioassay Analysis (IMBA), to analyze measurements of activity in the body and/or excreta and calculate the resulting doses. The software implements the International Commission on Radiological Protection's (ICRP's) currently recommended respiratory tract, tissue dosimetry, and biokinetic models for the reference worker, for 75 radionuclides. IMBA Professional Plus consists of a base unit and various Add-Ons which increase the functionality of the software. Users can thus customize the software to meet their individual requirements.

IMBA Professional Plus can be ordered directly from HPA at www.ImbaProfessional.com or can be supplied by ORTEC as part of a complete system.

The ORTEC technical development team has been upgrading whole-body counters for all of these reasons and more. Many customers have adopted the ORTEC CONNECTIONS-32 strategy for their counting laboratories and now for their whole-body counters as well. The combination of personal computers, Microsoft Windows 32-bit operating systems, and full networking support in addition to the high-quality electronics and RENAISSANCE software interface make an upgrade simple and straightforward.

Contact your local sales office to see how economical an upgrade can be!

Installation
ORTEC technical specialists can install, calibrate, and verify the system upgrade or software anywhere in the world. Installation consists of software setup on the PC, assistance in calibrating the system, verification of the system operation, and assembly of shield (where appropriate).

Training
ORTEC technical specialists can train your personnel in the use of the system at your facility or at the ORTEC Training Facility in Oak Ridge, Tennessee. Training includes theory of operation, hands-on software instruction, calibration of the system, Quality Assurance, and other customer-specified assistance.

Mechanical Specifications
StandFAST II Dimensions: 106.68 x 106.68 x 220.98 cm (42 x 42 x 87 in.)
Computer Requirements: Any PC capable of running Windows 2000/XP.

Table 1. Typical Detection Limits

	CI FastScan* 60 sec Std Man (nCi)	StandFAST II 60 sec Std Man (nCi)	StandFast II 60 sec Std Man CI Fastscan Method (nCi)	StandFast II 60 sec Empty (nCi)
⁶⁰Co	4.0 [148 Bq]	4.9 [181 Bq]	2.7 [100 Bq]	4.0 [148 Bq]
¹³⁷Cs	5.6 [207 Bq]	3.9 [144 Bq]	2.2 [81 Bq]	3.7 [137 Bq]
¹³⁴Cs	4.8 [178 Bq]	3.2 [118 Bq]	1.8 [67 Bq]	3.0 [111 Bq]
*From Canberra Systems Catalog, Edition 9