Fluke 37-040 User Manual

Nuclear Associates

37-040 (HD-810) and 37-041 (MD-55)

GAFCHROMIC® Therapy Dosimetry Media

Users Manual

Fluke Biomedical

Radiation Management Services

6045 Cochran Road Cleveland, Ohio 44139

440.498.2564

www.flukebiomedical.com/rms

Table of Contents

Section 1: Introduction................................................................................................ 1-1

1.1 GAFCHROMIC Dosimetry Media ................................................................ 1-1

1.2 Description................................................................................................... 1-1

1.3 Labeling ....................................................................................................... 1-2

1.4 Handling....................................................................................................... 1-2

1.5 Storage of unexposed Dosimeters/Dosimetry Media................................... 1-2

1.5.1 Temperature........................................................................................... 1-2

1.5.2 Relative Humidity.................................................................................... 1-2

1.5.3 Visible Light ............................................................................................ 1-2

1.5.4 Ultraviolet Light....................................................................................... 1-3

1.5.5 Microwave Radiation .............................................................................. 1-3

1.5.6 Solvents.................................................................................................. 1-3

1.6 Storage of Exposed Dosimeters/Dosimetry Media ...................................... 1-3

1.6.1 Temperature........................................................................................... 1-3

1.6.2 Relative Humidity.................................................................................... 1-3

1.6.3 Visible Light ............................................................................................ 1-3

1.6.4 Ultraviolet Light....................................................................................... 1-4

1.6.5 Microwave Radiation .............................................................................. 1-4

1.6.6 Solvents.................................................................................................. 1-4

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1.1 GAFCHROMIC™ Dosimetry Media

• Sensitive to Gamma, Electron, X-ray, Deep

uv and Ionizing Radiation

• Self developing - no processing

• White light insensitive

• Dose rate independent

• Easy to use

Introduction

GAFCHROMIC Dosimetry Media

Section 1

Introduction

1.2 Description

GAFCHROMIC Dosimetry Media has been developed for use with ionizing radiation. The indicating film does not require any processing to develop or fix the image; the image is available for use immediately after the exposure has been completed.

The GAFCHROMIC Dosimetry Media is particularly useful for routine dosimetry, dose mapping, beam profiling and high-resolution radiography.

Exposed and unexposed dosimetry media has remarkable stability. Nevertheless, since there is no step analogous to the fixing step whereby unexposed silver halide is removed from conventional film, the film remains active indefinitely.

GAFCHROMIC dosimetry media have a 7-micron radiation sensitive layer on a 4-mil polyester base. It is colorless, grainless and transparent before exposure. The color is a function of the radiation exposure; higher exposures result in progressively darker blue. This change can be measured accurately (with a spectrophotometer or other device that measures optical density or absorbance) to calculate applied dosage.

GAFCHROMIC dosimetry media is composed of materials with low atomic numbers and will not alter the radiation fields of most products. Further, the material is insensitive to normal room light.

GAFCHROMIC dosimetry media may be used over a wide range of absorbed doses. Typical dose calibration tables are provided in Tables 1-1 and 1-2 for measurement with a spectrophotometer at 400, 500 and 580 nanometers. (When using a device other than a spectrophotometer the device should be calibrated using reference dosimeters.) Since there is some post-exposure darkening and changes in dose/density response at elevated temperatures, care should be taken to adjust readings using Table 1-

4. It is recommended that measurements be taken 24 hours after the end of irradiation. However, Table

1-5 allows for readings made at other times.

These instructions deal with the precautions that should be exercised when using or storing exposed or unexposed dosimeters/dosimetry film. When optimum storage conditions are maintained, it is believed

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Nuclear Associates 37-040 & 37-041

Operators Manual

that the exposed dosimetry media are likely to have archival qualities. This manual also contains specific directions for the labeling of all dosimetry media samples.

1.3 Labeling

Unexposed dosimetry media should always be labeled with the batch number of the product. In addition, a user label to identify the exposure conditions, date, time, etc., should always be used in conjunction with an exposed dosimeter. The batch numbers provide an audit trail whereby process conditions and raw materials can be identified and traced if a problem occurs.

The batch number is to be found printed on the package containing sheets of dosimetry media.

1.4 Handling

Unexposed and exposed dosimetry media should be handled only by the edges. It is recommended that the paper covering the coated side be left on, until immediately prior to reading the dosimeters, to protect the active coating. When writing on the media be careful not to exert pressure on the active area of other sheets of dosimetry media.

Prior to reading the dosimetry media, visually inspect the reading area to ensure that there are no flaws or marks, which might affect the reading. Remove loose particles by light rubbing with a lint-free paper or cloth. If flaws or marks cannot be removed and readings cannot be taken in other areas of the dosimeter, discard the dosimeter.

Unexposed dosimetry media should be handled by the edges or corners, taking care not to place fingerprints in areas of the film that are to be imaged. Wearing cotton gloves while handling film is recommended as the best way to avoid fingerprinting or scratching the film.

1.5 Storage of Unexposed Dosimeters/Dosimetry Media

1.5.1 Temperature

Where possible, store below 25°C (77°F). Although experiments have consistently shown that GAFCHROMIC dosimetry media suffer no ill effects at temperatures up to 50°C (122°F), adherence to a maximum storage temperature of 25°C (77°F) will provide the longest life. Never expose dosimetry media to temperatures exceeding 65°C (149°F).

1.5.2 Relative Humidity

When the dosimetry media are kept below 25°C (77°F), they should be unaffected by any humidity below 100%. However, a dry storage location at 50% RH, or less, is preferred.

1.5.3 Visible Light

Unopened boxes of dosimeters/dosimetry media are adequately protected against all visible light conditions. Although the dosimetry media have almost insignificant sensitivity towards visible light, it is recommended that opened packages of the media be kept away from all unnecessary exposure to light, particularly because visible light sources sometimes have an ultraviolet component that can be deleterious to the dosimeters. Therefore, store unexposed dosimeters/dosimetry media in their packages, with the covers closed.

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