Thresholds for thermal damage to normal tissues: An update

Abstract

The purpose of this review is to summarise a literature survey on thermal thresholds for tissue damage. This review covers published literature for the consecutive years from 2002–2009. The first review on this subject was published in 2003. It included an extensive discussion of how to use thermal dosimetric principles to normalise all time-temperature data histories to a common format. This review utilises those same principles to address sensitivity of a variety of tissues, but with particular emphasis on brain and testis. The review includes new data on tissues that were not included in the original review. Several important observations have come from this review. First, a large proportion of the papers examined for this review were discarded because time–temperature history at the site of thermal damage assessment was not recorded. It is strongly recommended that future research on this subject include such data. Second, very little data is available examining chronic consequences of thermal exposure. On a related point, the time of assessment of damage after exposure is critically important for assessing whether damage is transient or permanent. Additionally, virtually no data are available for repeated thermal exposures which may occur in certain recreational or occupational activities. For purposes of regulatory guidelines, both acute and lasting effects of thermal damage should be considered.

Thermal aspects of exposure to radiofrequency energy: Report of a workshop

“…The lack of a threshold, if real, would introduce an element of acceptable risk into the setting of exposure limits. In practice, the very large scatter in thermal damage data, evident in [7], is probably a more important source of uncertainty in identifying thresholds for clinically significant thermal damage to tissue.…”

“…In their article elsewhere in this volume [7], Dewhirst et al pointed to numerous shortcomings in the present data, which to a large extent result from inadequate thermal dosimetry. 'Most of the recent publications we found do not provide enough data for an accurate assessment of thermal tissue damage.…”

“…While the data are complex, an approximate lower boundary to the thermal injury data summarised by Dewhirst corresponds to a CEM43 of 1 min; much higher values of CEM43 are required to cause significant thermal injury to most tissues [7].…”

“…In his opening technical presentation and accompanying article [7], Mark Dewhirst reviewed the time-temperature thresholds for thermal damage to tissue. He updated his earlier (2003) review on thermal damage to tissues [8], including data from an additional 117 papers and also considering a wider range of biological endpoints.…”

Influence of hyperthermal regimes on experimental teratoma development in vitro

“…It is also important to avoid normal tissue damage that can or cannot be caused by different thermal exposures 4. To calculate a thermal isoeffect dose, the cumulative equivalent minutes at 43°C (CEM43°C) was introduced and used in studying the thermal damage in various systems 4, 5, 6.…”