Effective depth of spermatogonia in man I. Measurement of scrotal thickness

Abstract

Dosimetry for sperm cells irradiated by high-energy betas requires precise knowledge of the effective depth of the spermatogonia, and hence the thickness of overlying tissues (scrotum plus tunics), because beta dose rate changes very rapidly with depth. Measurements were made on 25 volunteers and surgical patients by mechanical caliper during surgery (2), by ultrasound (14), or by both (9), all at 20 degrees C air temperature. The tunica albuginea (TA) measured 0.1 mm. The surgical results (TA excluded) were 2.0 mm, sigma = 0.3 mm (n = 11). The ultrasound results (TA included) were 2.2 mm, sigma = 0.6 mm (n = 23). There was no correlation of scrotal thickness with age (24-83 years) and only a very weak correlation (r = 0.3) with body mass. There was no decrease in scrotal thickness (at 20 degrees C) with further warming but there was an increase (to 3.3 mm from 2.3 mm) with chilling before measurement. Ultrasound is shown to be valid for such measurements.

Hanford External Dosimetry Technical Basis Manual PNL-MA-842

“…Because whole body tissues of interest are primarily located at depths greater than 1 cm, significant effective dose from external sources typically requires radiation with a substantial X-ray or gamma ray component. However, the human testes are a special case because the tissues at risk lie at depths between 0.2 and 0.8 cm (Casey et al 1982;Facey 1982, Charles 1986) and can potentially receive beta dose (e.g. from 90 Y) as well as gamma dose from contamination on skin or clothing.…”