Slides to IAEA Nuclear Medicine Physics Handbook

Slides to IAEA Nuclear Medicine Physics Handbook

Chapter 9: Physics in the Radiopharmacy Slide set of 107 slides based on the chapter authored by R. C. Smart of the IAEA publication (ISBN 9789201438102): Review of Nuclear Medicine Physics: A Handbook for Teachers and Students Objective: To familiarize the student with the basic physics of the radiopharmacy laboratory. Slide set prepared in 2015 by R. Fraxedas (INEF, Havana, Cuba) IAEA International Atomic Energy Agency

CHAPTER 9 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9 9.10 9.11 TABLE OF CONTENTS

The modern radionuclide calibrator Dose calibrator acceptance testing and quality control Standards applying to dose calibrators National activity intercomparisons Dispensing radiopharmaceuticals for individual patients Radiation safety in the radiopharmacy Product containment enclosures Shielding for radionuclides Designing a radiopharmacy Security of the radiopharmacy Record keeping IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 2/107

9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.1 Construction of dose calibrators IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 3/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.1 Construction of dose calibrators Commercial systems comprise A typical dose calibrator (e.g. CRC 25R). a cylindrical well ionization chamber connected to a

microprocessor-controlled electrometer, providing calibrated measurements for a range of common radionuclides. The chamber is usually constructed of aluminium filled with argon under pressure (typically 12 MPa or 1020 atm). IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 4/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.1 Construction of dose calibrators

The chamber is typically shielded by the manufacturer with 6 mm of lead to ensure low background readings. If additional shielding is used, the dose calibrator should be recalibrated or correction factors determined to ensure that the activity readings remain correct. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 5/107

9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.1 Construction of dose calibrators SPECIFICATIONS OF TWO COMMERCIAL DOSE CALIBRATORS IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 6/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.2 Calibration of dose calibrators IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 7/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.2 Calibration of dose calibrators

A dose calibrator can be calibrated in terms of activity by comparison with an appropriate activity standard that is directly traceable to a national primary standard. The nuclide efficiency N can be expressed as the sum of two components: where pi(Ei) is the emission probability per decay of photons of energy Ei; i(Ei) is the energy dependent photon efficiency of the ionization chamber. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 8/107

9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.2 Calibration of dose calibrators Thin-walled aluminium Efficiency curve as a function of photon energy. chambers show a strong peak in efficiency at photon energies around 50 keV. Knowing the energy dependent photon efficiency curve for a specific ionization chamber will enable the nuclide efficiency for any radionuclide to be

determined from the photon emission probability for each photon in its decay. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 9/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.3 Uncertainty of activity measurements IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 10/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.3 Uncertainty of activity measurements

Major sources of uncertainty in dose calibrator measurements Calibration factor Electronics Statistical considerations Ion recombination Background radiation

Source container and volume effects Source position Source adsorption IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 11/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.3 Uncertainty of activity measurements 9.1.3.1 Calibration factor For Tc and 131I, the uncertainty of national standards is typically in

the range of 13%. 99m The calibration factor for different containers and/or a different volume may vary from the established calibration by a significant amount. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 12/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR

9.1.3 Uncertainty of activity measurements 9.1.3.2 Electronics Electrometers measure the current output from the ionization chamber ranging from tens of femtoamperes up to microamperes a dynamic range of 108. The potential for different linearity characteristics for each range may result in discontinuities when the range Electrometer inaccuracies (National Physical Laboratory Guide 2.1 ). is changed.

IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 13/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.3 Uncertainty of activity measurements 9.1.3.4 Ion recombination As the activity of the source increases, the probability of recombination of the positive ions with electrons increases. At high source activities, this can become significant and lead to a

reduction in the measured current. For most modern calibrators, the effects of recombination should be less than 1% when measuring 100 GBq of 99mTc. Effects of recombination (National Physical Laboratory Guide 2.2 ). IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 14/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.3 Uncertainty of activity measurements 9.1.3.6 Source container and volume effects

Variations in the composition and thickness of the source container will give rise to corresponding variations in the measured activity. These effects will be most noticeable for low energy photon emitters and pure beta emitters. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 15/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.3 Uncertainty of activity measurements 9.1.3.6 Source container and volume effects REDUCTION IN DOSE CALIBRATOR RESPONSE DUE TO INCREASES IN GLASS WALL THICKNESS OF 0.08 AND 0.2 mm Radionuclide

Reduction in response with increase in vial wall thickness of 0.08 mm 0.2 mm 125 I 3% 7% 123

I 0.6% 1.5% In 0.2% 0.4% I 0.1%

0.25% 111 131 IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 16/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.3 Uncertainty of activity measurements Variations in source geometry When the activity is drawn into a syringe, the source geometry will be different from that in a vial. Composition of the container, thickness and distribution

will affect the measurement. Self-absorption of the emitted radiation will change as the source volume changes. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 17/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.3 Uncertainty of activity measurements Activity measurements variation due to container type and size. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 18/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR

9.1.3 Uncertainty of activity measurements 9.1.3.7 Source position The manufacturers source holder is designed to keep the source at the area of maximum response on the vertical axis of the well. Variations in response due to changes in vertical height or horizontal position of a few millimetres are usually insignificant. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 19/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR

9.1.3 Uncertainty of activity measurements 9.1.3.8 Source adsorption Certain radiopharmaceuticals have been observed to adsorb to the surface of the container. Adsorbed activity can be a significant percentage of the total. The possibility of activity adsorption should be considered whenever the facility uses syringes from a different manufacturer. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 20/107

9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.4 Measuring pure beta emitters IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 21/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.4 Measuring pure beta emitters Characteristics of beta emitters measurement The detection efficiency of ionization chambers for beta radiation is low. The dose calibrator response from beta particles will be

almost entirely from bremsstrahlung radiation. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 22/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.4 Measuring pure beta emitters Measured activities of beta emitters In argon-filled ionization chambers, significant activities are required in order to obtain a precise estimate of the activity. However, as substantial activities of radionuclides are required to be used therapeutically, reliable measurements

are possible using pure beta emitters used clinically such as 90Y, 89Sr and 32P. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 23/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.4 Measuring pure beta emitters Dose calibrators efficiency The intrinsic efficiencies of dose calibrators can vary widely. Data from five different manufacturers showed that all systems had:

a good calibration for 32P. a reduction in efficiency of approximately 1020% for 89 Sr. a wide divergence in efficiency for 90Y. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 24/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.4 Measuring pure beta emitters 90 Y measurements The results obtained using the calibration factors supplied

by the manufacturers ranged from 64 to 144% of the true value. This re-emphasizes the need for the calibration to be confirmed within the nuclear medicine department. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 25/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.4 Measuring pure beta emitters 153 Sm and 186Re measurements

Sm (103 keV, 28% abundance) and 186Re (137 keV, 9.5% abundance) are gamma-beta emitting radionuclides. 153 For these radionuclides the ionization chamber efficiency is primarily determined by the gamma contribution and the manufacturers supplied calibrations will usually be accurate to within 10%. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 26/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR

9.1.5 Problems arising from radionuclide contaminants IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 27/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.5 Problems arising from radionuclide contaminants Radionuclide purity The proportion of the total radioactivity that is present as a specific radionuclide is defined as the radionuclide purity. National and international pharmacopoeia specify the radionuclidic purity of a radiopharmaceutical.

IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 28/107 9.1 THE MODERN RADIONUCLIDE CALIBRATOR 9.1.5 Problems arising from radionuclide contaminants Effects of contaminants The presence of contaminants, even when less than 1% of the total activity, can have a marked effect on the ionization chamber current and, thus, on the measured activity. The presence of high energy contaminants will have an adverse effect on image quality due to increased septal penetration and will also lead to an increased radiation

dose to the patient. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 29/107 9.2 DOSE CALIBRATOR ACCEPTANCE TESTING AND QC 9.2.1 Acceptance tests IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 30/107 9.2 DOSE CALIBRATOR ACCEPTANCE TESTING AND QC 9.2.1 Acceptance tests Acceptance tests for dose calibrators

Accuracy and reproducibility Linearity Geometry response IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 31/107 9.2 DOSE CALIBRATOR ACCEPTANCE TESTING AND QC 9.2.1 Acceptance tests 9.2.1.1 Accuracy and reproducibility The accuracy is determined by comparing activity measurements using a traceable calibrated standard with the suppliers stated activity, corrected for radioactive decay.

The reproducibility, or constancy, can be assessed by taking repeated measurements of the same source. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 32/107 9.2 DOSE CALIBRATOR ACCEPTANCE TESTING AND QC 9.2.1 Acceptance tests 9.2.1.2 Linearity Methods for assessment of linearity of dose response: Decaying source method Multiple dilutions method Graded attenuators method

IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 33/107 9.2 DOSE CALIBRATOR ACCEPTANCE TESTING AND QC 9.2.1 Acceptance tests 9.2.1.3 Geometry response The measured activity may vary with: the position of the source within the ionization chamber the composition of the vial or syringe the volume of liquid within the vial or syringe Correction factors can be determined for the different volumes or containers used.

IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 34/107 9.2 DOSE CALIBRATOR ACCEPTANCE TESTING AND QC 9.2.2 Quality control IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 35/107 9.2 DOSE CALIBRATOR ACCEPTANCE TESTING AND QC 9.2.2 Quality control 9.2.2.1 Background check Even if the source holder is empty, the dose calibrator will

still record an activity due to background radiation. At a minimum, the background should be determined each morning before the dose calibrator is used, and recorded. The technologist should also confirm the absence of any additional background before all activity measurements during the day. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 36/107 9.2 DOSE CALIBRATOR ACCEPTANCE TESTING AND QC 9.2.2 Quality control 9.2.2.2 Check source reproducibility

A long lived check source should be used on a daily basis to confirm the constancy of the response of the dose calibrator. Sealed radioactive sources of 57Co and 137Cs, shaped to mimic a vial, are available commercially for this purpose. The check source should be measured on all radionuclide settings that are used clinically. A reading outside of that expected from previous results may indicate a faulty dose calibrator or a change in calibration factor. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 37/107 9.3 STANDARDS APPLYING TO DOSE CALIBRATORS

IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 38/107 9.3 STANDARDS APPLYING TO DOSE CALIBRATORS International and national standards The International Electrotechnical Commission (IEC) has published two standards and a technical report relating to dose calibrators. IEC standards are often adopted by national standards organizations. There should also be national standards covering dose calibrators. The American National Standards Institute publication ANSI N42.13-2004 is often referenced by US

manufacturers. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 39/107 9.4 NATIONAL ACTIVITY INTERCOMPARISONS IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 40/107 9.4 NATIONAL ACTIVITY INTERCOMPARISONS National metrology institutes are responsible for the development and maintenance of standards, including activity standards and have undertaken national comparisons of the accuracy of the dose calibrators used

in clinical practice. Such comparisons have used, where possible, the clinical radionuclides 67Ga, 123I, 131I, 99mTc and 201Tl. In some countries they are voluntary, while in others it is mandatory. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 41/107 9.4 NATIONAL ACTIVITY INTERCOMPARISONS SUMMARY OF THE RESULTS OF THE DOSE CALIBRATOR SURVEY UNDERTAKEN IN AUSTRALIA IN 2007 IAEA

Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 42/107 9.5 DISPENSING RADIOPHARMACEUTICALS FOR INDIVIDUAL PATIENTS 9.5.1 Adjusting the activity for differences in patient size and weight IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 43/107 9.5 DISPENSING RADIOPHARMACEUTICALS FOR INDIVIDUAL PATIENTS 9.5.1 Adjusting the activity for differences in patient size and weight Protocols

Protocols used in nuclear medicine practices should specify the usual activity of the radiopharmaceutical to be administered to a standard patient. If a fixed activity is used for all patients, this will lead to an unnecessarily high radiation exposure to an underweight patient and may lead to images of unacceptable quality or very long imaging times in obese patients. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 44/107 9.5 DISPENSING RADIOPHARMACEUTICALS FOR INDIVIDUAL PATIENTS 9.5.1 Adjusting the activity for differences in patient size and weight Scaling factors

Scaling factors for the activity, to give a constant effective dose, can be derived from the expression (W/70)a where W represents the weight of the person and the power factor a is specific for the radiopharmaceutical (ICRP 53,80,106). IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 45/107 9.5 DISPENSING RADIOPHARMACEUTICALS FOR INDIVIDUAL PATIENTS 9.5.1 Adjusting the activity for differences in patient size and weight THE POWER FACTOR a RELATING BODY WEIGHT TO A CONSTANT EFFECTIVE DOSE ACCORDING TO THE EXPRESSION (W/70)a FOR 14 COMMON RADIOPHARMACEUTICALS

Radiopharmaceutical a value 99m Tc-DMSA 0.706 99m Tc-DTPA 0.801

99m Tc-MAG3 0.520 99m Tc-HMPAO 0.849 99m Tc-MAA

0.842 99m Tc-sestamibi 0.871 99m Tc-phosphonates 0.763 Radiopharmaceutical Tc-IDA

0.840 Tc-tetrafosmin 0.834 Tc-red cells 0.859 Tc-white cells 0.869 F-FDG

0.782 Ga-citrate 0.931 I or 131I iodide 1.11 99m 99m a value

99m 99m 18 67 123 IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 46/107 9.5 DISPENSING RADIOPHARMACEUTICALS FOR INDIVIDUAL PATIENTS 9.5.2 Paediatric dosage charts IAEA

Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 47/107 9.5 DISPENSING RADIOPHARMACEUTICALS FOR INDIVIDUAL PATIENTS 9.5.2 Paediatric dosage charts Paediatric dose considerations Children are approximately three times more radiosensitive than adults, so determining the appropriate activity to be administered for paediatric procedures is essential. In addition to the scaling factor to be applied to the adult activity, a minimum activity must be specified in order to ensure adequate image quality. IAEA

Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 48/107 9.5 DISPENSING RADIOPHARMACEUTICALS FOR INDIVIDUAL PATIENTS 9.5.2 Paediatric dosage charts Dose scaling factors In the past, the scaling factors were assessed using weight alone or body surface area obtained from both height and weight. Recently, the European Association of Nuclear Medicine (EANM) Dosimetry and Paediatric Committees have prepared a dosage card which recognizes that a single scaling factor is not optimal for all radiopharmaceuticals. Radiopharmaceuticals could be grouped into three classes (renal, thyroid and others), with different scaling factors for

each class. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 49/107 9.5 DISPENSING RADIOPHARMACEUTICALS FOR INDIVIDUAL PATIENTS 9.5.2 Paediatric dosage charts A dosage card is available on the EANM web site that gives the minimum recommended activity and a weight dependent scaling factor for each radiopharmaceutical. It was determined to give weight independent

effective doses. An app for iOs and Android devices featuring the chart is now available. IAEA Dosage card can be accessed online: http://www.eanm.org/docs/EANM_Dosage_Card_040214.pdf? PHPSESSID=sf56mg9ehjv5r9t4v50mre3375 Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 50/107 9.5 DISPENSING RADIOPHARMACEUTICALS FOR INDIVIDUAL PATIENTS 9.5.3 Diagnostic reference levels in

nuclear medicine IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 51/107 9.5 DISPENSING RADIOPHARMACEUTICALS FOR INDIVIDUAL PATIENTS 9.5.3 Diagnostic reference levels in nuclear medicine Diagnostic reference levels The ICRP introduced in 1996 the term diagnostic reference level (DRL) for patients. DRLs are investigation levels and are based on an easily measured quantity, usually the entrance surface dose in the case of diagnostic radiology, or the administered activity in the case of nuclear medicine. DRLs are referred to by the IAEA as guidance levels in

Safety Report Series No. 40. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 52/107 9.6 RADIATION SAFETY IN THE RADIOPHARMACY 9.6.1 Surface contamination limits IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 53/107 9.6 RADIATION SAFETY IN THE RADIOPHARMACY 9.6.1 Surface contamination limits External and internal contamination

Surface contamination with radioactivity could lead to: contamination of a radiation worker external irradiation of the skin of the worker Internal contamination could arise from inhalation of the radionuclide ingestion of the radionuclide IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 54/107 9.6 RADIATION SAFETY IN THE RADIOPHARMACY 9.6.1 Surface contamination limits

DERIVED LIMITS FOR SURFACE CONTAMINATION The surface contamination limits given in this table were derived based on a committed effective dose limit of 20 mSv/a and the models for inhalation and ingestion given in ICRP publications IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 55/107 9.6 RADIATION SAFETY IN THE RADIOPHARMACY 9.6.2 Wipe tests and daily surveys IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 56/107

9.6 RADIATION SAFETY IN THE RADIOPHARMACY 9.6.2 Wipe tests and daily surveys Surveys of the radiopharmacy areas To ensure that contamination limits are not exceeded, surveys of radiopharmacy areas should be routinely done. Logical sequence of surveys Use survey meter to find unexpected exposed sources. Check surfaces with contamination meter with appropriate probe, according to the radionuclides used. Use wipe tests for areas of high background or for low energy beta emitters. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 57/107

9.6 RADIATION SAFETY IN THE RADIOPHARMACY 9.6.2 Wipe tests and daily surveys Wipe tests A minimum area of 100 cm2 should be wiped. Activity can be assessed using a pancake probe, or more accurately in a well counter. For low energy beta emitters such as 3H or 14C, liquid scintillation counting must be used. When quantifying the surface contamination, it is generally assumed that a wipe test using a dry wipe will remove one tenth of the contamination. It is assumed that a wet wipe will remove one fifth of the contamination. IAEA

Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 58/107 9.6 RADIATION SAFETY IN THE RADIOPHARMACY 9.6.3 Monitoring of staff finger doses during dispensing IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 59/107 9.6 RADIATION SAFETY IN THE RADIOPHARMACY 9.6.3 Monitoring of staff finger doses during dispensing Hand and finger doses The most exposed parts of the hands are likely to be the tips of the

index and middle fingers, and the thumb of the dominant hand. Finger doses may approach or exceed the annual dose limit of 500 mSv to the extremities. A practical way to monitor hands is to wear a ring monitor at the base of the finger. The ICRP recommends that the ring monitor be worn on the middle finger with the element positioned on the palm side, and that a factor of three should be applied to derive an estimate of the dose to the tip. The dose to the fingers is critically dependent on the dispensing technique used and the skill of the operator. IAEA

Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 60/107 9.7 PRODUCT CONTAINMENT ENCLOSURES 9.7.1 Fume cupboards IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 61/107 9.7 PRODUCT CONTAINMENT ENCLOSURES 9.7.1 Fume cupboards A fume cupboard is an enclosed Fume cupboard suitable for use with radioactive materials

workplace designed to prevent the spread of fumes to the operator and other persons. The fume cupboard is designed to provide operator protection rather than protection for the product within the cabinet. The most common type of fume cupboard is known as a variable exhaust air volume fume cupboard which maintains a constant velocity of air into the cabinet (the face velocity). IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 62/107

9.7 PRODUCT CONTAINMENT ENCLOSURES 9.7.1 Fume cupboards Cupboard air discharge Air discharge type Direct (or through filter) to the atmosphere. Recirculating, after filtration or absorption (normally not applicable in radiopharmacies). Air discharged must meet local regulatory requirements. Smoke tests should be performed as part of QC schedule. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 63/107 9.7 PRODUCT CONTAINMENT

ENCLOSURES 9.7.2 LAMINAR FLOW CABINETS IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 64/107 9.7 PRODUCT CONTAINMENT ENCLOSURES 9.7.2 Laminar flow cabinets Laminar flow cabinets characteristics Laminar flow cabinets provide a non-turbulent airstream of near constant velocity, which has a substantially uniform flow cross-section and with a variation in velocity of not more than 20%. Laminar flow cabinets provide product protection while a fume cupboard is designed to provide operator protection. The air supplied to the cabinet is usually passed through a high

efficiency particulate air filter (99.999%). Operator protection cannot be ensured if airflow is disturbed during radiopharmaceutical manipulation. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 65/107 9.7 PRODUCT CONTAINMENT ENCLOSURES 9.7.3 Isolator cabinets IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 66/107 9.7 PRODUCT CONTAINMENT ENCLOSURES 9.7.3 Isolator cabinets

Isolator cabinets characteristics Isolator cabinets provide both operator and product protection, used frequently for cell labelling. The product is manipulated through glove ports so that the interior of the cabinet is maintained totally sterile and full operator protection is provided. The isolator incorporates timed interlocks on the vacuum door seals to ensure that the product remains sterile. IAEA

Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 67/107 9.8 SHIELDING FOR RADIONUCLIDES 9.8.1 Shielding for gamma, beta and positron emitters IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 68/107 9.8 SHIELDING FOR RADIONUCLIDES 9.8.1 Shielding for gamma, beta and positron emitters Shielding requirements and materials Shielding is required

in the walls of the radiopharmacy. in any containment enclosures. in a body shield to protect the operator at the dispensing station around individual vials and syringes containing radionuclides. Shielding materials for different purposes Lead and concrete in walls. Lead or tungsten in local shielding for gamma emitting radionuclides. Aluminium or Perspex for pure beta emitters (to minimize bremsstrahlung radiation). IAEA

Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 69/107 9.8 SHIELDING FOR RADIONUCLIDES 9.8.1 Shielding for gamma, beta and positron emitters Shielding for beta emitters For beta emitters, the thickness of the shielding must be greater than its range to ensure that all betas are absorbed. Polymethyl methacrylate (Perspex or lucite) has a density of 1.19 g/cm3, similar to the density of tissue and water, and is highly suitable for absorbing betas. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 70/107

9.8 SHIELDING FOR RADIONUCLIDES 9.8.1 Shielding for gamma, beta and positron emitters MAXIMUM BETA ENERGY AND THE RANGE IN WATER FOR FOUR BETA EMITTERS USED CLINICALLY IN NUCLEAR MEDICINE Radionuclide Emax (MeV) Range in water (mm) 14 C 0.156

0.30 32 P 1.709 8.2 89 Sr 1.463

6.8 90 Y 2.274 11 IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 71/107 9.8 SHIELDING FOR RADIONUCLIDES 9.8.1 Shielding for gamma, beta and positron emitters

Doses due to generators The highest surface dose rates encountered in the radiopharmacy are likely to be from 99Mo/99mTc generators. It requires several centimetres of lead shielding to reduce the dose rates to an acceptable level. The generator as supplied will already contain substantial shielding but additional shielding will usually be required.

IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 72/107 9.8 SHIELDING FOR RADIONUCLIDES 9.8.1 Shielding for gamma, beta and positron emitters Manipulation of vials Vials of radiopharmaceuticals must be kept shielded. The shields are usually constructed so that only the rubber septum of the vial is accessible, thereby protecting the hands of the operator during dispensing.

IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 73/107 9.8 SHIELDING FOR RADIONUCLIDES 9.8.1 Shielding for gamma, beta and positron emitters Manipulation of vials Measurements in calibrators are done with the unshielded vials, increasing the exposure to the operator. Long forceps should always be used to manipulate radioactive vials. IAEA

Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 74/107 9.8 SHIELDING FOR RADIONUCLIDES 9.8.1 Shielding for gamma, beta and positron emitters Manipulation of syringes Syringe shields must be used whenever possible. These must be made of Perspex for the pure beta emitters and of lead or tungsten for the gamma emitters. A leadglass window is necessary to permit observation of the

contents of the syringe. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 75/107 9.8 SHIELDING FOR RADIONUCLIDES 9.8.2 Transmission factors for lead and concrete IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 76/107 9.8 SHIELDING FOR RADIONUCLIDES 9.8.2 Transmission factors for lead and concrete Transmission factors characteristics The attenuation of monoenergetic photons through

materials such as lead or concrete will be exponential, characterized by the linear attenuation coefficient or the half-value layer (HVL). This is only true for narrow beam geometries. Moreover, non-monoenergetic radionuclides emit more than one gamma photon and their attenuation cannot be expressed as a simple HVL. Measured broad-beam transmission factors are available for lead and concrete, two of the most common shielding materials. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 77/107 9.8 SHIELDING FOR RADIONUCLIDES 9.8.2 Transmission factors for lead and concrete MEASURED TRANSMISION FACTORS FOR LEAD

IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 78/107 9.8 SHIELDING FOR RADIONUCLIDES 9.8.2 Transmission factors for lead and concrete MEASURED TRANSMISSION FACTORS FOR CONCRETE (DENSITY: 2.35 g/cm3) IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 79/107 9.9 DESIGNING A RADIOPHARMACY IAEA

Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 80/107 9.9 DESIGNING A RADIOPHARMACY Location of a radiopharmacy The radiopharmacy should be located in an area that is not accessible to members of the public. There should be easy access from the radiopharmacy to the injection rooms and imaging rooms to minimize the distance that radioactive materials need to be transported. The radiopharmacy should not be adjacent to areas that require a low and constant radiation background such as a counting room. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 81/107

9.9 DESIGNING A RADIOPHARMACY Storage needs for the radiopharmacy A refrigerator will be required for the storage of lyophilized radiopharmaceutical kits. A storage area will be required for reconstituted radiopharmaceuticals, in shielded containers, together with radiopharmaceuticals purchased ready for dispensing such as 67Ga-citrate and 201Tl-chloride. The radiopharmacy must contain facilities for radioactive waste disposal. In addition, there must be shielded containers for sharps, such as

syringes with needles. A separate shielded storage bin may be required if a large number of bulky items, such as aerosol or Technegas kits, need to be stored . IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 82/107 9.9 DESIGNING A RADIOPHARMACY Areas of the radiopharmacy There should be an area within the radiopharmacy designated as a non-active area that is used for record keeping and/or computer entry . A dedicated dispensing area with a body shield and leadglass viewing window will be required. If a Mo/Tc generator is used, this should be positioned away from the

dispensing area to minimize the dose received by the person dispensing the radiopharmaceuticals. Labelling areas are dependent of the type of radiopharmaceutical that will be prepared, generally requiring specialized equipment. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 83/107 9.9 DESIGNING A RADIOPHARMACY Dedicated equipment for specific labelling techniques If cell labelling procedures are to be performed, a dedicated area with a laminar flow cabinet or isolator will be required to ensure that the product remains sterile during the labelling procedure. A fume cupboard, together with an activated charcoal filter on the exhaust, will be required if radio-iodination procedures are to be

performed. Some radiopharmaceuticals require a heating step in their preparation. This is often performed using a temperature controlled heating block. This must be in a dedicated separately shielded area,. Similarly, the radiolabelling of blood samples may require local shielding of mixers and centrifuges. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 84/107 9.9 DESIGNING A RADIOPHARMACY Characteristics of surfaces Wall, floor and ceiling surfaces should be smooth, impervious and durable, and free of externally mounted features such as

pipes or ducts to facilitate any radioactive decontamination. Bench surfaces should be constructed of plastic laminate or resin composites or stainless steel, and benches must be able to safely withstand the weight of any required lead shielding. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 85/107 9.9 DESIGNING A RADIOPHARMACY Contamination monitoring A contamination monitor must be

available in a readily accessible location. A wall-mounted monitor to check for any hand contamination should be mounted near the exit from the radiopharmacy. A model which can be removed and used as a general contamination monitor is useful. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 86/107 9.9 DESIGNING A RADIOPHARMACY Decontamination facilities

Hand washing facilities must be available which can be operated without the use of the operators hands to prevent the spread of any contamination. An eye-wash should also be available. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 87/107 9.10 SECURITY OF THE RADIOPHARMACY IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 88/107 9.10 SECURITY OF THE RADIOPHARMACY

Category of radioactive sources The IAEA has categorized radioactive sources on a scale of 1 to 5, based on activity and nuclide, where category 1 is potentially the most hazardous. Sources categorized as 1, 2 or 3 are known as security-enhanced sources. The security measures in place for safety purposes are considered adequate to ensure the physical security of category 4 and 5 sources. A Mo/Tc generator with an activity of greater than 300 GBq is a category 3 source. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 89/107 9.10 SECURITY OF THE RADIOPHARMACY

Physical security of radioactive sources Radioactive materials are at most risk of being stolen or lost when they are being transported to and from the facility. It is essential that all consignments of radioactive materials to the nuclear medicine facility are left in a secure area and not left, for example, on a loading dock. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 90/107 9.10 SECURITY OF THE RADIOPHARMACY Radiopharmacy access Whether secure access (such as electronic card access) to the radiopharmacy during working hours is required will depend on local requirements and the layout of the nuclear medicine department.

It is essential that only trained nuclear medicine staff have access to the radiopharmacy. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 91/107 9.11 RECORD KEEPING IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 92/107 9.11 RECORD KEEPING Record generation and keeping Records can be generated as part of the quality assurance (QA) programme.

for the receipt and subsequent administration of a radiopharmaceutical to a patient. for waste disposal. The local regulations may specify the form in which these must be kept (paper and/or electronic). the minimum records that must be kept at the facility. the time for which the records must be kept. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 93/107 9.11 RECORD KEEPING 9.11.1 Quality control records IAEA

Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 94/107 9.11 RECORD KEEPING 9.11.1 Quality control records Records should at the very least include details of: Acceptance testing of the dose calibrator All constancy tests Radiopharmaceutical testing IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 95/107 9.11 RECORD KEEPING 9.11.1 Quality control records

Record of failures and malfunctions Failures identified at acceptance testing. Failures of constancy testing. Failures of radiopharmaceutical testing. The actions taken to remedy those failures. All these should be documented and these records kept for the lifetime of the equipment. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 96/107 9.11 RECORD KEEPING 9.11.1 Quality control records Generator elutions records

The following records should be kept for all generator elutions: Time of elution Volume of eluate 99m 99 Tc activity Mo activity

Radionuclidic purity IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 97/107 9.11 RECORD KEEPING 9.11.2 Records of receipt of radioactive materials IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 98/107 9.11 RECORD KEEPING 9.11.2 Records of receipt of radioactive materials Radioactive materials records Complete records should be kept of:

The radionuclide Activity Chemical form Supplier Suppliers batch number Purchase date On arrival, if a package containing radioactive material is suspected of being damaged, the package should be:

Monitored for leakage with a wipe test; Checked with a survey meter for unexpectedly high external radiation levels. If a package is damaged or suspected of being damaged, the supplier should be contacted immediately, and the details recorded IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 99/107 9.11 RECORD KEEPING 9.11.3 Records of radiopharmaceutical preparation and dispensing IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 100/107 9.11 RECORD KEEPING

9.11.3 Records of radiopharmaceutical preparation and dispensing Radiopharmaceutical preparations records Records of each preparation should include the: Name of the radiopharmaceutical Cold kit batch number Date of manufacture Batch number of final product Radiochemical purity results Expiry date IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 101/107 9.11 RECORD KEEPING 9.11.3 Records of radiopharmaceutical preparation and dispensing

Patient dose dispensed records A record for each patient dose dispensed must be kept with the: Name of the patient Name of the radiopharmaceutical Measured radioactivity Time and date of measurement IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 102/107 9.11 RECORD KEEPING 9.11.4 Radioactive waste records IAEA

Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 103/107 9.11 RECORD KEEPING 9.11.4 Radioactive waste records Characteristics of Nuclear Medicine radioactive wastes Radioactive waste generated within a nuclear medicine facility usually consists of radionuclides with half-lives of less than one month. This waste will normally be stored on-site, be allowed to decay to background radiation levels. After decay, it can then be disposed of as normal waste or biologically contaminated waste. IAEA

Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 104/107 9.11 RECORD KEEPING 9.11.4 Radioactive waste records Radioactive waste packages labelling Each package of waste (bag, sharps container, wheeled bin) must be marked with the: Radionuclide, if known. Maximum dose rate at the surface of the container or at a fixed distance (e.g. 1 m). Date of storage. IAEA

Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 105/107 9.11 RECORD KEEPING 9.11.4 Radioactive waste records Records information and update The wastes information should be recorded, together with information identifying the location of the container within the store, and the likely release date (e.g. ten half-lives of the longest lived radionuclide in the container). When the package is finally released for disposal, the record should be updated to record the dose rate at that time, which should be at background levels, the date of disposal, and the identification of the person authorizing its disposal.

IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 106/107 9.11 RECORD KEEPING 9.11.4 Radioactive waste records Disposal of old sealed sources Old sealed sources, previously used for quality control or transmission scans, such as 137Cs 57Co 153Gd 68Ge should be kept in a secure store until the activity has decayed to a level permitted for disposal, or the source can be disposed of by a

method approved by the regulatory authority. IAEA Nuclear Medicine Physics: A Handbook for Teachers and Students Chapter 9 Slide 107/107

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