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The Brigham and Women's Hospital is an ~700 bed broad-scope licensed facility with a vigorous fluoroscopy service. Concomitant with this service is an equally robust quality management program to safeguard both patient and personnel from excessive radiation doses. The FDA, in an attempt to avoid serious skin injury for certain fluoroscopically guided procedures, issued a Public Health Advisory in 1994. Four years later the institutional Radiation Safety Committee voted to expand an existing fluoroscopic safety course to include a more formal credentialing/safety requirement. The specific parameters associated with this program follow.

The Brigham and Women's Hospital is an approximately 700 bed broad-scope licensed facility with a vigorous fluoroscopy service. Concomitant with this service is an equally robust quality management program to safeguard both patient and personnel from excessive radiation doses. The FDA, in an attempt to avoid serious skin injury for certain fluoroscopically guided procedures, issued a Public Health Advisory in 1994. Four years later the institutional Radiation Safety Committee voted to expand an existing fluoroscopic safety course to include a more formal credentialing/safety requirement. The specific parameters associated with this program follow.

The concentration of 111In in breast milk in a 10 weeks postpartum woman was measured at daily intervals up to 72 h post-injection of 5.3 mCi (196 MBq) of 111In-octreotide (OctreoScan). Radiation surveys were also performed at the breast surface. The disappearance of 111In from the breast milk exhibited a bi-exponential pattern with a maximum concentration of 14.2 nCi (0.54 kBq) per 125 ml feeding at 4 h, with lower values thereafter. External surveys at the breast surface also showed a bi-exponential decrease with time. The maximum reading was 8.3 mrem x h(-1) (0.83 mSv x h(-1)) immediately after administration. This rapidly decreased due to 85% urinary excretion by 24 h. Breast milk tracer content and external surveys at the breast surface were determined at 3 h intervals for up to 10 days. If a newborn is nursed for the first 10 days, the internal and external dose equivalents would be 22.97 mrem (0.23 mSv) and 27.86 mrem (0.28 mSv), respectively, for a total of 50.83 mrem (0.5 mSv). The patient was instructed to resume breast-feeding on day 10, when the newborn received a total dose equivalent of 1.55 mrem (0.016 mSv). This dosimetry is based on a very conservative assumption, whereby 100% of the ingested 111In becomes systemic and follows adult bio-behaviour. Oral indium has been shown to be poorly absorbed from the gastrointestinal tract (approximately 0.15%), which suggests the infant's dose could be considerably less. Based on this case report, mathematical relationships are presented for determining the nursing infant's dose equivalent from internal and external exposures relative to time after the maternal administration of 111In-octreotide (OctreoScan).

Rationale and Objectives: Little is known about the time-related biologic behavior of radiopharmaceutical misinjections. Such inadvertent tissue infiltration of such injections may not only adversely affect a scheduled test or cause some discomfort, but potentially could produce tissue damage. Radiopharmaceutical infiltrations were assessed in a rat model., Methods: Particulate and nonparticulate radiopharmaceuticals were injected subcutaneously or intradermally into an anesthetized shaved rat model. The rate of release of the nine infiltrations per radiopharmaceutical per injection type were measured from computer data acquired with a gamma camera up to 24 hours after administration. These data were used for dosimetry determinations., Results: When injected subcutaneously, the particulate radiopharmaceutical, technetium 99m (99mTc) albumin microspheres, exhibited essentially no movement, and the soluble agents showed a biexponential release pattern. The rate of release was similar for 99mTc methylene diphosphonate (99mTc MDP) and for 67Ga citrate (67Ga), whereas thallous chloride (201Tl) exhibited the slowest release pattern. The average effective half-lives (T1/2 av-eff) were 78.3 minutes, 76.1 minutes, and 268.4 minutes, respectively. When injected intradermally, the nonparticulates exhibited a triexponential release pattern; MDP showed a more rapid release (T1/2 av-eff, 50 minutes) and 201Tl showed the slowest (T1/2 av-eff, 491.2 minutes). Absorbed doses were calculated using conventional medical internal radiation dose (MIRD) methodology for small unit density spheres. The absorbed dose was greatest for a 201Tl infiltration. A 201Tl infiltrate of 1 mCi per gm of tissue is capable of producing radiation-absorbed doses greater than 500 rads. Additional studies were performed with heat, hyaluronidase, and volume dilution in an attempt to accelerate the rate of release of 201Tl. Local heat application proved to be more efficient than volume change or hyaluronidase application., Conclusion: These data indicate an insignificant skin radiation burden from the majority of nonparticulate infiltrated radiodiagnostic agents. Thallium 201, however, has the potential to produce significant radiation burdens when infiltrated at high specific activity. Actual human infiltration release rates may differ because of variants in blood flow and assumed infiltration volume relative to the animal model.

Rationale and Objectives: The communication of a suitable radiation risk consent form statement to a potential research subject has always been difficult to formulate. Concomitant with this is the equally problematic task of ensuring that subjects understand the true risks of the study. In an effort to document how other Institutional Review Boards (IRBs) express radiation risk associated with participating in a research investigation, a questionnaire was developed and was sent to 23 large medical-research institutions., Methods: Questions pertained to the manner of comparing risk, units for expressing radiation dose, patient population differentiation, and statements for given situations. In addition, each institution was asked to provide examples of radiation-related in-house consent form statements. Thereafter, the examples were forwarded to the responding institutions for grading., Results: Fourteen responses were received and summarized. The majority compared the study test to a similar radioactivity study, Nuclear Regulatory Commission (NRC) occupational limits and/or Radioactive Drug Radiation Committee (RDRC) limits. There was an equal distribution of radiation units used; absorbed dose, dose equivalent, and effective dose equivalent. The majority of respondents did not differentiate between normal individuals and patient volunteers. Included in the 14 responses were 46 in-house generated radiation-related consent form statements. The latter were assembled and forwarded to the 14 responding institutions with instructions to "approve" or "disapprove" each. Nine statements obtained an 80% or greater acceptance rating, with three > 90%. The remaining were overwhelmingly rejected as suitable radiation risk statements., Conclusions: Based on the submitted material and statement grading results, recommendations were formulated toward producing a standard format for expressing radiation risk in the consent form. Effective dose equivalent in comparison to annual natural environmental radiation or occupational radiation dose limits were recommended based on these data. While an "optimum" radiation risk consent form statement may not be attainable, these results nevertheless provide recommendations based on a consensus of practitioners in the field.

A review of the literature pertaining to the human dosimetry of 201Tl-labelled thallous chloride provides a spectrum of organ absorbed doses associated with this radiopharmaceutical. A more recent article details human quantitative studies up to 216 h postadministration. This multiorgan radiopharmacological study, however, reports the kidney dosimetry to be significantly lower than previous values; 0.0647 mGy MBq1 (0.238 rad mCi-1) compared to 0.326 mGy MBq-1 (1.2 rad mCi-1). Because of the latter discrepancy the dosimetry was recalculated using the reported pharmacodynamic data. This recalculation resulted in a kidney radiation dose comparable to previously published reports of 0.514 mGy MBq-1 (1.89 rad mCi-1). Also, revised absorbed doses to the various segments of the gastrointestinal tract (GIT) were significantly higher.

Efficient control over the purchase and receipt of radioactive material is a necessary part of any radiation safety program. We describe a novel computerized method for monitoring the flow of radioactive material within a large broad-licensed medical research complex. The Local Area Network (LAN) described interfaces the radiation safety office with radionuclide receiving, the authorized user, grants and contracts, special accounts, and purchasing. Task-specific software enables the authorized user to place an order and allows the monitoring of possession/ordering limits, personnel, date of order, and time of receipt via the screen. The resultant data base is easily annexed for specific information. The system is user-friendly and adaptable to any set of circumstances.

The concentration of 125I-phenylphosphate (I phi PA), a long-lived bone-seeking radio-pharmaceutical (T1/2 biol = 962 days) that localizes in acute infarction (MI), was studied in 30 rats after ligation of the anterior descending coronary artery. At 23 h postMI, I phi PA was given intravenously to all animals, and five of this group received 99Tcm-pyrophosphate (99Tcm-pyro) intravenously. These five rats were sacrificed 2 h later and the content of I phi PA and 99Tcm-pyro activities was determined for normal and infarcted (INF) heart segments. There is a zone of INF that contains residual I phi PA which also concentrates 99Tcm-pyro consistently after MI. This zone may represent jeopardized myocardium which has not undergone complete necrosis.