Exposure of patients to ionising radiation during lung cancer diagnostic work-up.

We examined the dose of radiation received during diagnosis of lung cancer as this may add to the risk of a second primary cancer. Patients undergoing surgery (n=40) or (chemo)radiotherapy (n=40) received comparable doses (28.6 and 25.8 mSv, respectively), significantly higher than that for supportive care (n=40; 15.1 mSv). The effective dose of radiation received was higher for early stage disease than for those with metastatic disease. The mean lifetime attributable risk of malignancy for those receiving treatment with curative intent in our cohort was 0.059%, and lung-specific risk 0.019%.

CT pulmonary angiography versus ventilation-perfusion scintigraphy in pregnancy: implications from a UK survey of doctors' knowledge of radiation exposure.

PURPOSE: To prospectively investigate the fetal dosimetry knowledge of health care professionals involved in the management of pulmonary embolism. MATERIALS AND METHODS: One hundred sixty-one health care professionals consented to participate in this study, which had ethical board approval. The individuals surveyed were from 14 hospitals (seven university and seven community hospitals) in the United Kingdom, and 68 trainees were included. These health care professionals included 102 radiologists, 13 nuclear physicians, seven dual-accredited radiologist-nuclear medicine physicians, 16 medical physicists, and 23 pulmonologists. The interview included eight questions. Two questions asked which examination-computed tomographic (CT) pulmonary angiography or ventilation-perfusion (V/Q) scintigraphy-gave (a) the larger radiation exposure (effective dose) to an adult and (b) the larger fetal dose. Two questions assessed the magnitude of the dose differences between these two tests. Four questions asked for an estimate of the dose to both adult and fetus from CT pulmonary angiography and scintigraphy. Subgroup analysis was performed by using the Fisher exact test. RESULTS: Of the 161 professionals surveyed, 93 (58%) appreciated correctly that V/Q scintigraphy delivers a higher fetal dose than does CT pulmonary angiography. Three of 161 professionals were able to answer all eight questions correctly. In terms of the knowledge that V/Q scintigraphy has a higher fetal dose than does CT, there was no statistically significant difference in correct answers between specialties (P > .05), between university and community hospitals (P = .13), or between attending physicians and residents (P = .52). CONCLUSION: This survey reveals that there is a lack of knowledge of fetal dosimetry in the imaging of pregnant women suspected of having pulmonary embolism.

Irradiating cell samples in an x-ray radiation cabinet--the effect of tube filtration.

The cell irradiation cabinet described is used for creating DNA damage in cell samples in order to study tumourigenesis. The medical research laboratory involved was using the manufacturer's quoted dose rate (32.2 mGy s(-1)) to determine the required exposure time to impart a dose of 10 Gy. The x-ray output was investigated when the exposure failed to produce cell cycle arrest. The x-ray tube was fitted with only a 0.76 mm beryllium filter, and the spectrum therefore contained a high proportion of low energy photons which were being removed by the polystyrene sample flask as demonstrated by dose measurements in air and through the sample flask. Incorporation of a 0.5 mm aluminium filter removed most of these low energy photons but greatly reduced the dose rate to 3.8 mGy s(-1). The manufacturer's quoted dose rates from a lightly filtered tube are misleading: the contribution of the very low energy component of the spectrum to the dose is not relevant since it will be removed by a sample flask.