Bioelectromagnetics 21:432 ^438 (2000)
A M agnetic Fi e ld Exposure Faci lity for
Eval uatio n of An i m al Carcinoge n icity
P.S. Maruvada,
1
S.M. Harvey,
2
P. Jutras,
1
D. Goulet,
3
* and R. Mandeville
4
1
PS M Consulting, Bouch ervill e, Qu e
¨
bec , Canada
2
SAIC Canada, Brampton , Ontario, Canada
3
Tr a n s E
¨
nerg ie, Mo ntre
¨
al, Que
¨
bec , Canada
4
B iophage I nc ., Montre
¨
al, Que
¨
bec , Canada
Several animal studies have been carried out at the Institut Armand Frappier (IAF) to determine
whether chronic exposure to 60 Hz linearly polarized sinusoidal magnetic fields might increase the
risk of cancer development of female Fisher rats. The magnetic field exposure facility was
developed to meet the requirements of the study protocol for chronic exposure of large number of
animals to field intensities of sham < 0.2 mT, 2 mT, 20 mT, 200 mT, and 2000 mT. At each exposure
level, including sham, the animals are distributed in a group of four exposure units. Each exposure
unit contains two exposure volumes having uniform distribution of magnetic fields for the animals,
while the magnetic field external to the unit falls off rapidly due to the ``figure-eight'' coil
topography used. A program of ``shake down'' tests, followed by verification and calibration of the
exposure facility, was carried out prior to starting the animal experiments. Continuous monitoring
of the magnetic field and other environmental parameters was an important part in the overall
quality assurance program adopted. Bioelectromagnetics 21:432±438, 2000.
ß 2000 Wiley-Liss, Inc.
Key words: laboratory study; animal carcinogenicity; magnetic fields; 60 Hz
INTRODUCTION
Following Wertheimer and Leeper [1979], a
number of epidemiological studies have been carried
out to determine whether exposure to power±fre-
quency magnetic ®elds (MFs) is associated with the
occurrence of certain types of cancer, particularly
leukemia, brain tumors, and breast cancer in men and
women. The results obtained so far show, however, that
the indices supporting any hypothesis that exposure
to MFs may cause cancer are very weak. Inherent
dif®culties in the methodology, such as dosimetry for
exposure assessment, absence of dose±response rela-
tionship and the small number of cases studied, limit
the interpretation of results obtained from epidemio-
logical studies. In order to obtain de®nitive informa-
tion on cause-and-effect relationships, there is a need
for carefully designed animal studies that would offer
the possibility of exposing large number of inbred
animals to graded intensities of power±frequency MFs
in a carefully controlled environment.
One of the ®rst such studies has been carried
out at the Institut Armand-Frappier (IAF), Montreal,
Quebec, with the objective of determining whether
chronic exposure to 60 Hz linearly polarized sinusoidal
MFs of different intensities might increase the risk of
leukemia and solid tumor development in female F344
rats [Mandeville et al., 1993, 1997, 1999; Tremblay,
1996]. The study design required exposure of ®ve
groups of 50 rats each for 20 h/day to MFs at intensities
of < 0.2 (sham controls), 2, 20, 200, and 2000 mTovera
period of 104 weeks. The study protocol also required
careful control of MF intensities and other environ-
mental parameters as well as double-blind operation of
the exposure facility. The design, operation, veri®ca-
tion, monitoring, and maintenance of a high quality
exposure system developed for this study is described
in this paper.
MATERIALS AND METHODS
Tec hnical Specifications for the
Exposure Facility
In order to meet the requirements of the study
design and the experimental protocol, technical
ß 2000 Wiley-Liss,Inc.
ÐÐÐÐÐÐ
*Correspondence to: Dr. Daniel Goulet, Direction Expertise et
Support technique de transport; TRANSENERGIE, 800 boul. De
Maisonneuve est, 21e e
Â
tage, Montreal, P.Q.; Canada H2L 4M8.
E-mail: goulet.daniel@hydro.qc.ca
Received 1 March 1999; Final revision received 10 November
1999.