When reviewing internal hospital policies, we often find ourselves exploring interesting terrain that is not charted in a typical corporate transactional law practice.  An example is a policy regarding the receipt and opening of packages delivered to the hospital that contain radioactive materials.

The typical use for such materials is for diagnostic imaging in nuclear medicine that finds details in bones and organs not available with standard X-rays.  A tiny amount of a radioisotope is put into the body, and, once absorbed; tends to concentrate in certain targeted places depending upon the radionuclide used.  The isotope emits gamma rays or positrons that can be detected by a scanner in various forms of tomography.  Radioisotopes are also used in treatment for certain tumors.

These issues are covered by regulations of the Nuclear Regulatory Commission as set forth in 10 CFR § 20.1906 that can be found here.  If the package is expected to contain quantities of radioactive materials in excess of a Type A quantity, the staff is instructed to perform certain tasks as soon as possible but no later than 3 hours after receipt.

Among those tasks are:

• making arrangements to receive the package when delivered,
• conducting a radiation survey of the external surface of packages for contamination that are labeled with certain radioactive symbols,
• wipe testing the exterior surface, and
• notifying the carrier and the NRC Operations Center (301) 816-5100 if the wipe test or the radiation survey reveal contamination above certain levels.

Those certain levels are referenced in 10 CFR § 71.87 and set forth in 49 CFR § 173.443. Many policies specify that the wipe test is to be conducted using a 1” patch to wipe an area of 100cm².  However, the regulations expressly require a wipe covering an area of 300 cm² (about 7” x 7”).  The objective of the wipe test is to discover if there is non-fixed surface contamination (after subtracting the background radiation) that exceeds 220 dpm/cm² (disintegrations or decays per minute). 

The limits of the radiation survey are set forth in 10 CFR § 71.47 and the results must not exceed 200 mR/hr (milli-Roentgens) which is about the normal exposure of a human being to background radiation in a year.

Readings in excess of either of these amounts require certain actions in addition to the call to the NRC Operation Center.

The exceptions are if the radioactive materials are in the form of a gas or in a special form, which is defined in 10 CFR § 71.4 as a solid piece of material or is contained in a sealed capsule that can only be opened by destroying the capsule.

If the package shows signs of potential contamination such as being wet, crushed or damaged, the wipe test and external radiation survey must be performed regardless of the amount of materials that are expected to be delivered.

In a typical hospital or nuclear pharmacy, most packages of radioactive materials used in clinical nuclear medicine will not contain materials in a special form or in quantities greater than Type A quantities.  The issue is: what are Type A quantities?  That’s where things get tricky for the reviewing attorney who is not also a physicist.

      Type A quantities are defined in 10 CFR § 71.4 as follows:

Type A quantity means a quantity of radioactive material, the aggregate radioactivity of which does not exceed A1 for special form radioactive material, or A2, for normal form radioactive material, where A1 and A2 are given in Table A-1 of this part, or may be determined by procedures described in Appendix A of this part.

Let’s unpack that text (without a wipe test).  Since, in this context, we’re not generally interested in special form materials, we need to know the A2 values.  Those can be found in Table A-1 of the Appendix A to Part 71 here.  The problem arises in converting the regulatory and International System of Units standard of radioactivity of Terabecquerel (TBq) units to curie (Ci) units which are deemed by the NRC to be merely “informational”.  However, the methodology employed in the typical sophisticated university teaching hospital or nuclear pharmacy will often produce measurements in curies.

This is the part where we get into the weeds.

One Ci is defined as 3.7 x 10¹⁰ decays per second, roughly equal to the behavior of 1 gram of radium.  One Becquerel (Bq) is defined as one decay per second.  So one Ci is equal to 3.7 x 10¹⁰ Bq.  The inverse is that one Bq is equal to 2.703 x 10^-11.

Let’s jack it up.  One Terabecquerel is equal to one trillion Bq or 1 x 10¹².  Therefore, one Ci is equal to 0.037 TBq.  And one TBq is equal to 27.027 Ci.  For those who are calculus-challenged, here’s a dandy conversion tool.  However, even the tool will not help with the scientific notation, so the decimal points have to be counted correctly.

With all that established, let’s discover the relevance.  Hospital policies must reflect the correct math when determining the Type A quantities for various radionuclides that may be expected in a package at the receiving dock and accurately detail the techniques and evaluation of the wipe test and survey, the results of which control the behavior of the employees under the NRC regulations.

Here is a table of the typical radionuclides that would be delivered to the hospital pharmacy and the correct A2 values that meet the Type A quantity threshold.

 

Radionuclide	A2 TBq	A2 Ci
Mo-99 (see note 1)	.6	16
Tc-99m	4	108
I-131	.7	19
Cs-137	.6	16
Ir-192	.6	16
I-125	3	81

 

Note 1:  While the NRC table shows these values, the daughter nuclides produced by the disintegration in the decay process, which has a half-life of less than 10 days, is included in the number along with the parent.  The Type A amount for domestic use is 20 Ci.

A correctly written hospital pharmacy policy would include an accurate description of the process, including the requirements of a log, as well as correct statements of the radioactive limits in units of measurements that are likely to be employed in that facility followed by precise instructions for action depending upon the results. 

Tags: hospital, policies, radionuclides