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IAEA Training Material on Radiation Protection in Nuclear Medicine. Part 6. Medical Exposure Protection of the Patient. Objective.

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slide1

IAEA Training Material on Radiation Protection in Nuclear Medicine

Part 6

Medical Exposure

Protection of the Patient

objective
Objective

To become familiar with the BSS detailed requirement for medical exposure in nuclear medicine: responsibilities, justification, optimization, guidance level, dose constraints accidental exposure and medical records

Part 6. Medical Exposure

contents
Contents
  • Introduction
  • Responsibilities
  • Justification
  • Optimization of examination
  • Guidance levels of activity
  • Dose constraints
  • Examination of children, pregnant women and lactating women
  • Records
  • Local rules

Part 6. Medical Exposure

part 6 medical exposure protection of the patient

Part 6. Medical ExposureProtection of the Patient

IAEA Training Material on Radiation Protection in Nuclear Medicine

Module 6.1. Introduction

medical exposure definition
Medical Exposure(Definition)

“Exposure incurred by patients as part of their own medical or

dental diagnosis or treatment; by persons, other than those

occupationally exposed, knowingly while voluntarily helping in

the support and comfort of patients; and by volunteers in a

programme of biomedical research involving their exposure.”

Part 6. Medical Exposure

slide6

Protection of

the patient

Part 6. Medical Exposure

slide7

Protection of

comforters

and visitors

Part 6. Medical Exposure

protection from what
Protection from What?
  • Unnecessary examination or treatment (justification)
  • Unnecessary exposure (optimization)
  • Inadequate examinations, which can lead to incorrect or incomplete diagnosis (optimization)

Part 6. Medical Exposure

slide9
Mr. Sharp, I am given to understand that 2 bone scans and a cardiac study done on me have given me 22 mSv whereas 20 mSv is the safe dose. I want to file legal suit against the doctor. What do you feel??

Part 6. Medical Exposure

slide10
Medical Exposure

versus

Occupational

Part 6. Medical Exposure

slide11

My resident doctor has got 12 mSv in her last badge report as she was wearing the badge while getting her barium study. She wants off from radiation work.

?????

Part 6. Medical Exposure

slide12

Medical Exposure

versus

Occupational Exposure

Part 6. Medical Exposure

slide13

While caring for his spouse Mr. Joseph got 2 mSv.

As a member of the public with 1 mSv dose limit, he can not get any radiation dose this year.

???????

Part 6. Medical Exposure

medical exposure bss interim edition
MedicalExposure(BSS: InterimEdition)
  • Responsibilities
  • Justification of medical exposure
  • Optimization of protection for medical exposure
  • Guidance levels
  • Dose constraints
  • Maximum activity for patients in therapy on discharge from hospital
  • Investigation of accidental medical exposures
  • Records

Part 6. Medical Exposure

part 6 medical exposure protection of the patient1

Part 6. Medical ExposureProtection of the Patient

IAEA Training Material on Radiation Protection in Nuclear Medicine

Module 6.2. Responsibilities

responsibilities bss 2011
Responsibilities: BSS (2011)
  • “3.149. The regulatory body shall ensure that the authorization for medical exposures to be performed at a particular medical radiation facility allows personnel (radiological medical practitioners, medical physicists, medical radiation technologists and any other health professionals with specific duties in relation to the radiation protection of patients) to take on the responsibilities specified in these Standards only if they:
    • (a) are specialized in the appropriate area;
    • (b) meet the respective requirements for education, training and competence in radiation protection,
    • (c) are named in a list maintained up to date by the registrant or licensee.”

Part 6. Medical Exposure

responsibilities bss 2011 contd
Responsibilities: BSS (2011) contd.
  • “3.150. Registrants and licensees shall ensure that no patient, whether symptomatic or asymptomatic, undergoes a medical exposure unless:
    • The radiological procedure has been requested by a referring medical practitioner and information on the clinical context has been provided, or it is part of an approved health screening programme;
    • (b) The medical exposure has been justified through consultation between the radiological medical practitioner and the referring medical practitioner, as appropriate, or it is part of an approved health screening programme;
    • (c) A radiological medical practitioner has assumed responsibility for protection and safety in the planning and delivery of the medical exposure;
    • (d) The patient or the patient’s legal authorized representative has been informed, as appropriate, of the expected diagnostic or therapeutic benefits of the radiological procedure as well as the radiation risks.”

Part 6. Medical Exposure

responsibilities bss 2011 contd1
Responsibilities: BSS (2011) contd.
  • “3.153. Registrants and licensees shall ensure that:
    • (a) The radiological medical practitioner performing or overseeing the radiological procedure has assumed responsibility for ensuring overall protection and safety for patients during the planning and delivery of the medical exposure, including the justification of the procedure as required in paras 3.154–3.160 and the optimization of protection and safety, in cooperation with the medical physicist and the medical radiation technologist as required in paras 3.161–3.176;
    • (b) Radiological medical practitioners, medical physicists, medical radiation technologists and other health professionals with specific duties in relation to protection and safety for patients in a given radiological procedure have the appropriate specialization;
    • (c) Sufficient medical personnel and paramedical personnel are available as specified by the health authority;”
    • . *Interim version of revised BSS

Part 6. Medical Exposure

responsibilities bss 2011 contd2
Responsibilities: BSS (2011) contd.
  • “(d) For therapeutic uses of radiation, the requirements of these Standards for calibration, dosimetry and quality assurance, including the acceptance and commissioning of medical radiological equipment, as specified in paras 3.166, 3.167(c), 3.169 and 3.170, are fulfilled by or under the supervision of a medical physicist;
  • (e) For diagnostic radiological procedures and image guided interventional procedures, the requirements of these Standards for medical imaging, calibration, dosimetry and quality assurance, including the acceptance and commissioning of medical radiological equipment, as specified in paras 3.166, 3.167(a), 3.167(b), 3.168, 3.169 and 3.170, are fulfilled by or under the supervision of or with the documented advice of a medical physicist, whose degree of involvement is determined by the complexity of the radiological procedures and the associated radiation risks;
  • (f) Any delegation of responsibilities by a principal party is documented.”

Part 6. Medical Exposure

slide20

How to apply this

in nuclear medicine?

Part 6. Medical Exposure

factors affecting medical exposure
FACTORS AFFECTINGMEDICAL EXPOSURE

Request

Examination or treatment

Biomedical research

Patient identification

and information

Administration of

radiopharmaceutical

Examination

Treatment

Child ?

Lactating woman ?

Pregnant woman ?

Safe preparation of

prescribed radio-

pharmaceutical and

activity

Dose constraints

Method

Quality of equip-ment

Correct use of equipment

Dose constraints to comforters and visitors

Accidental medical exposure

Who is responsible?

Part 6. Medical Exposure

responsibility structure
RESPONSIBILITY STRUCTURE

Licensee/Hospital management

Optimization of medical exposure

through

organization and resources

Nuclear Medicine Department

Referring physician

Optimization of medical exposure

through well educated personnel

with clearly defined responsibilities

NM specialist

Qualified expert

NM technologist

Nurse

Engineer

Radiopharmacist

Justification

of medical exposure

Part 6. Medical Exposure

referring physician
Referring Physician
  • Prescribe and justify diagnostic procedures and therapy in writing in co-operation with the nuclear medicine specialist

Part 6. Medical Exposure

administrative manager
Administrative Manager
  • Appoint the necessary personnel and ensure the individuals
  • have the necessary education to perform their duties.
  • Establish a radiation protection programme and provide the
  • necessary resources.
  • Assign clear responsibilities for personnel.
  • Appoint a Radiation Protection Officer.
  • Establish a comprehensive QA programme.
  • Support education and training of personnel.

Part 6. Medical Exposure

nuclear medicine staff
Nuclear Medicine Staff
  • Individuals with key positions, i.e., responsibilities for protection and safety and those who could substantially affect protection and safety by virtue of tasks involving operation or manipulation of sources, or equipment which could lead to an accidental exposure should have documented evidence of education and training. The objective is to ensure that only qualified personnel fill such positions. In nuclear medicine, these individuals are:
  • Nuclear medicine physicians
  • Qualified experts in nuclear medicine physics (medical physicists)
  • Other health professionals in nuclear medicine (radiopharmacists,

nuclear medicine technologists, nurses,…)

  • Radiation Protection Officer

Part 6. Medical Exposure

personal authorization
Personal Authorization
  • To obtain the personal authorization, the nuclear medicine staff should comply with the following requirements:
    • university degree or equivalent relevant to the profession by

the competent education authorities as required in the

country;

    • accreditation to exercise the profession granted by the

competent authorities or institutions as required in the

country;

    • course on radiation protection for which the contents, the

methodology and the teaching institution are approved by

the Regulatory Authority. This course may be integrated in

the curricula of the professional education; and

    • on the job training supervised by professionals with

authorization by the Regulatory Authority.

Part 6. Medical Exposure

nuclear medicine specialist
Nuclear Medicine Specialist
  • Ensure overall patient protection and safety;
  • provide consultation and clinical evaluation of patients
  • ensure that the exposure of patients be the minimum required to achieve the intended objective;
  • take into account relevant information from previous examinations in order to avoid unnecessary additional examinations;
  • take into account the relevant guidance levels for medical exposure;
  • determine dose prescription for therapy in consultation with the medical physicist; and
  • provide evaluation of any radiation incident and accident from medical point of view.

Part 6. Medical Exposure

medical physicist
Medical Physicist
  • Participate in continuing review of the nuclear medicine practice’s resources (including budget, equipment, and staffing), operations, and policies and procedures;
  • Develop requirements and specifications for the purchase of appropriate equipment assuring radiation safety;
  • Plan in conjunction with the nuclear medicine physician the facilities for nuclear medicine practice;
  • Carry out acceptance testing;
  • Establish dose calculation procedures in nuclear medicine therapy;
  • Establish and implement QA procedures in nuclear medicine;
  • Supervise equipment maintenance;
  • Investigate and evaluate incidents and accidents.

Part 6. Medical Exposure

nuclear medicine technologist
Nuclear Medicine Technologist
  • Patient identification;
  • Patient information;
  • Information to accompanying persons and staff nursing a patient after a nuclear medicine examination or therapy;
  • Verifying that the female patient is non-pregnant;
  • Assure that a mother in lactation is given information about discontinuation of nursing;
  • Make the calculation of administered activity to a child according to the local rules;
  • Verify the administered radiopharmaceutical and its activity;
  • Perform regular quality control of activity meter and other relevant equipment;
  • Perform regular workplace monitoring;
  • Correct handling of the equipment and safety accessories;
  • Inform the RPO in the case of accident or incident;
  • Inform the Nuclear Medicine Physician in the case of misadministrations;
  • Participate in education and training of new personnel.

Part 6. Medical Exposure

part 6 medical exposure protection of the patient2

Part 6. Medical ExposureProtection of the Patient

IAEA Training Material on Radiation Protection in Nuclear Medicine

Module 6.3. Justification

justification
Justification

Although Nuclear Medicine is a justified diagnostic tool

a case-by-case justification shall be applied.

This is the responsibility of the referring physician in

co-operation with the nuclear medicine specialist and

other specialists in diagnostic imaging, taking relevant

guidelines into account.

Part 6. Medical Exposure

justification bss 2011
Justification :BSS (2011)

Relevant parties shall ensure that medical exposures are justified:

“3.154. Medical exposures shall be justified by weighing the expected diagnostic or therapeutic benefits that they yield against the radiation detriment that they might cause, with account taken of the benefits and the risks of available alternative techniques that do not involve medical exposure.

3.155. Generic justification of a radiological procedure shall be carried out by the health authority in conjunction with appropriate professional bodies, and shall be reviewed from time to time, with account taken of advances in knowledge and technological developments.”

Part 6. Medical Exposure

justification bss 2011 contd
Justification: BSS (2011) Contd…
  • “3.156. The justification of medical exposure for an individual patient shall be carried out through consultation between the radiological medical practitioner and the referring medical practitioner, as appropriate, with account taken, in particular for patients who are pregnant or breast-feeding or paediatric, of:
    • (a) The appropriateness of the request;
    • (b) The urgency of the procedure;
    • (c) The characteristics of the medical exposure;
    • (d) The characteristics of the individual patient;
    • Relevant information from the patient’s previous radiological procedures.
  • 3.157. Relevant national or international referral guidelines shall be taken into account for the justification of the medical exposure of an individual patient in a radiological procedure.”

Part 6. Medical Exposure

justification bss 2011 contd1
Justification: BSS (2011) contd..

“3.158. Justification for radiological procedures to be performed as part of a health screening programme for asymptomatic populations shall be carried out by the health authority in conjunction with appropriate professional bodies.

3.159. Any radiological procedure on an asymptomatic individual that is intended to be performed for the early detection of disease, but not as part of an approved health screening programme, shall require specific justification for that individual by the radiological medical practitioner and the referring medical practitioner, in accordance with the guidelines of relevant professional bodies or the health authority. As part of this process, the individual shall be informed in advance of the expected benefits, risks and limitations of the procedure.”

Part 6. Medical Exposure

justification bss 2011 contd2
Justification: BSS (2011) contd…

“ 3.160. The medical exposure of volunteers as part of a programme of biomedical research is deemed to be not justified unless:

  • (a) It is in accordance with the provisions of the Helsinki Declaration [20] and takes into account the guidelines published by the Council for International Organizations of Medical Sciences [21], together with the recommendations of the ICRP [22];
  • (b) It is subject to approval by an ethics committee (or other institutional body that has been assigned similar functions by the relevant authority), subject to any dose constraints that may be specified (as required in paras 3.148(a)(ii) and 3.173), and subject to applicable national regulations and local regulations.”

Part 6. Medical Exposure

part 6 medical exposure protection of the patient3

Part 6. Medical ExposureProtection of the Patient

IAEA Training Material on Radiation Protection in Nuclear Medicine

Module 6.4. Optimization of Examination

otimization of patient examination
Otimization ofPatient Examination

Diagnostic Objective Medical Exposure

Part 6. Medical Exposure

optimization of medical exposure in nuclear medicine
Optimization of Medical Exposure in Nuclear Medicine

“3.162. For diagnostic radiological procedures and image guided interventional procedures, the radiological medical practitioner, in cooperation with the medical radiation technologist and the medical physicist, and if appropriate with the radiopharmacist or radiochemist , shall ensure that the following are used:

  • (a) Appropriate medical radiological equipment and software and also, for nuclear medicine, appropriate radiopharmaceuticals;
  • (b) Appropriate techniques and parameters to deliver a medical exposure of the patient that is the minimum necessary to fulfil the clinical purpose of the procedure, with account taken of relevant norms of acceptable image quality established by relevant professional bodies and relevant diagnostic reference levels established in accordance with paras 3.147 and 3.168.”

Part 6. Medical Exposure

optimization contd
Optimization contd...

“3.163. For therapeutic radiological procedures, the radiological medical practitioner, in cooperation with the medical physicist and the medical radiation technologist, shall ensure that for each patient the exposure of volumes other than the planning target volume is kept as low as reasonably achievable consistent with delivery of the prescribed dose to the planning target volume within the required tolerances.

3.164. For therapeutic radiological procedures in which radiopharmaceuticals are administered, the radiological medical practitioner, in cooperation with the medical physicist and the medical radiation technologist, and if appropriate with the radiopharmacist or radiochemist, shall ensure that for each patient the appropriate radiopharmaceutical with the appropriate activity is selected and administered so that the radioactivity is primarily localized in the organ(s) of interest, while the radioactivity in the rest of the body is kept as low as reasonably achievable.”

Part 6. Medical Exposure

optimization contd1
Optimization contd...

“3.165. Registrants and licensees shall ensure that the particular aspects of medical exposures are considered in the optimization process for:

  • (a) Paediatric patients subject to medical exposure;
  • (b) Individuals subject to medical exposure as part of a health screening programme;
  • (c) Volunteers subject to medical exposure as part of a programme of biomedical research;
  • (d) Relatively high doses to the patient;
  • (e) Exposure of the embryo or fetus, in particular for radiological procedures in which the abdomen or pelvis of the pregnant woman is exposed to the useful radiation beam or could otherwise receive a significant dose;
  • (f) Exposure of a breast-fed infant as a result of a female patient undergoing a radiological procedure with radiopharmaceuticals.

Part 6. Medical Exposure

optimization of medical exposure
Optimization of Medical Exposure

Radionuclide

Biokinetics

Patient

Administered

activity

Effective

dose

Quality of

equipment etc

Radiation risk

Image quality

Part 6. Medical Exposure

radiopharmaceuticals
Radiopharmaceuticals
  • Considering that, according to the BSS, the activities listed below also require authorization, regulatory authorities may require the licensee of a nuclear medicine practice to contract any of the following services only to enterprises authorized by the Regulatory Authority:
      • production, import, distribution, sale or transfer of

radioactive sources

      • personal monitoring
      • installation, maintenance of nuclear medicine

equipment

      • disposal of radioactive sources

Use only radiopharmaceuticals from an authorized

manufacturer!

Part 6. Medical Exposure

radiopharmaceuticals1
Radiopharmaceuticals

If more than one radiopharmaceutical can be used for a procedure consideration should be given to physical, chemical and biological properties.

Example: Leucocytes labelled with

In-111Tc-99m

0.36 mSv/MBq 0.011 mSv/MBq

20 MBq 7.2 mSv 200 MBq  2.2 mSv

T1/2 = 2.8 days T1/2 = 6 hours

Part 6. Medical Exposure

radiopharmaceuticals2
Radiopharmaceuticals

Tl-201 Tc-99m

25 mSv 8 mSv

Part 6. Medical Exposure

optimization of image quality
Optimization of Image Quality

Image quality depends on:

  • Administered activity
  • Technical factors - equipment used - acquisition protocol - image processing & evaluation - noise - spatial resolution

- scatter

  • Patient factors - size

- age

- disease - movement

Part 6. Medical Exposure

optimization of administered activity
Optimization of Administered Activity

In general, doses should be maintained as low as reasonable

achievable but high enough to obtain the desired diagnostic

information. This means that exposures above clinically

acceptable maximum doses must be avoided as well as doses

below clinically acceptable minimum doses

Part 6. Medical Exposure

optimization of administered activity1
Optimization of Administered Activity

Value of diagnostic information

There is a threshold below

which no useful information

can be expected

Above this threshold the

diagnostic quality increases

steeply with the administered

activity

Once an acceptable level has

been reached further increase

of activity will not improve

the result

(ICRP 52)

Administered activity

Part 6. Medical Exposure

slide48

Administered Activity to Children

Optimization is Necessary!

Administered activity to children referred to DMSA scan in Swedish hospitals

Part 6. Medical Exposure

noting the special requirements for patients with impairment of organ function
…..noting the special requirements for patients with impairment of Organ Function

normal partially obstructed totally obstructed

function outflow outflow

Part 6. Medical Exposure

optimization
Optimization
  • (ii) use of methods for blocking the uptake in organs not under study and for accelerated excretion when applicable;
  • Blocking agents for thyroid
  • Hydration and frequent voiding of the urinary bladder
  • Laxatives
  • Catheterisation to empty the bladder???
  • Cholecystokinin (fatty meal) for gallbladder emptying

Part 6. Medical Exposure

optimization1
Optimization

(iii) appropriate image acquisition and processing;

  • Equipment used:
  • Single head/dual head camera
  • Collimator used

Part 6. Medical Exposure

aquisition protocol
Aquisition Protocol

Static? Tomographic?

Dynamic?

Part 6. Medical Exposure

acquisition protocol
Acquisition Protocol

Static imaging - matrix size

- number of counts

- projections, zoom

Dynamic imaging - matrix size

- time/frame

- number of groups

Tomographic imaging - 180o or 360o

- matrix size

- number of angles

- time/angle

Part 6. Medical Exposure

image processing evaluation
Image Processing & Evaluation

Static - smoothing

- image filtering

- quantification

- applications programme

Dynamic - regions of interest (ROI)

- time-activity curves

- application programme

Tomographic - attenuation correction

- reconstruction method

- image filtering

- slices displayed

- application programme

Part 6. Medical Exposure

noise
Noise
  • Random variations in the number of counts (N) in a pixel, ROI or in a point in a time-activity curve
    • true uptakes may not be seen
    • false uptakes may occur
    • uncertainty in quantitative values
  • Lower noise requires more administered activity or longer acquisition times
  • Noise SD %

Part 6. Medical Exposure

noise1
Noise

1000000 counts 100000 counts

Part 6. Medical Exposure

phantom different number of counts
Phantom: Different number of counts

50 k 250 k 1000 k

Part 6. Medical Exposure

thyroid scintigraphy different acquisition times
Thyroid Scintigraphy,different acquisition times

1 min

2 min

4 min

8 min

Part 6. Medical Exposure

the noise level versus activity levels for an adult cbf
The noise level versus activity levels for an adult, CBF

Eleonor Westergren

Part 6. Medical Exposure

spatial resolution
Spatial Resolution
  • Describes how a point source is reproduced
    • small details are not seen
    • uptakes seem to be lower
  • Improved spatial resolution can be achieved by changing to a collimator with higher resolution but:
    • lower sensitivity requires more administered activity or longer acquisition times

Part 6. Medical Exposure

appropriate image acquisition
Appropriate Image Acquisition

Close 15 cm Wrong setting

of energy window

Part 6. Medical Exposure

patient factors
Patient Factors

Size increased scatter

spatial resolution

Age & Disease radiopharmaceutical distribution

movement artifacts

Part 6. Medical Exposure

image quality patient movement
Image QualityPatient Movement

Movement

Corrected

Part 6. Medical Exposure

staff and procedures
Staff and Procedures
  • Well trained staff with access to manuals
  • and other documentation.
  • Quality control program.
  • Regular maintenance of equipment

Part 6. Medical Exposure

part 6 medical exposure protection of the patient4

Part 6. Medical ExposureProtection of the Patient

IAEA Training Material on Radiation Protection in Nuclear Medicine

Module 6.5. Reference Levels of Activity

diagnostic reference levels bss
Diagnostic Reference Levels (BSS)
  • “3.168. Registrants and licensees shall ensure that:
    • (a) Local assessments, on the basis of the measurements required in para. 3.167, are made at approved intervals for those radiological procedures for which diagnostic reference levels have been established (para. 3.147);
    • (b) A review is conducted to determine whether the optimization of protection and safety for patients is adequate, or whether corrective action is required if, for a given radiological procedure:
    • (i) typical doses or activities exceed the relevant diagnostic reference level; or
    • (ii) typical doses or activities fall substantially below the relevant diagnostic reference level and the exposures do not provide useful diagnostic information or do not yield the expected medical benefit to the patient.”

Part 6. Medical Exposure

reference levels of activity
Reference Levels of Activity

Part 6. Medical Exposure

reference levels
Reference Levels

How to establish:

1. Elimination of outliers

2. State-of-the practice (good practice)

3. State-of-the art (optimal practice)

Part 6. Medical Exposure

slide70

Distribution of Administered Activities

Log-normal distributions

Number of patients

Activity

Optimized?

Guidance level

Part 6. Medical Exposure

slide71

Activity, MBq

Max

IAEA guidance level

Mean and range of mean (Sweden, 1995)

Optimized?

Bone scintigraphy

Part 6. Medical Exposure

part 6 medical exposure protection of the patient5

Part 6. Medical ExposureProtection of the Patient

IAEA Training Material on Radiation Protection in Nuclear Medicine

Module 6.6. Dose Constraints: Volunteers and Comforters

dose constraints
Dose Constraints

“3.151. Registrants and licensees shall ensure that no individual incurs a medical exposure as part of a programme of biomedical research unless the exposure has been approved by an ethics committee (or other institutional body that has been assigned similar functions by the relevant authority) as required in para. 3.160 and a radiological medical practitioner has assumed responsibility as specified in para. 3.153(a). Registrants and licensees shall ensure that the requirements specified in para. 3.173 are met for the optimization of protection and safety for persons subject to exposure as part of a programme of biomedical research.”

Part 6. Medical Exposure

biomedical research

Level of Risk:

Trivial

Minor to

Intermediate

Moderate

Risk Category:

I

I.A.

I.

III

Total detriment

~ 10-6 or less

~ 10-5

~ 10-4

~ 10-3 or more

Range of effective doses (adults), mSv

< 0.1

0.1 - 1

1 - 10

> 10a

Anticipated level of benefit to Society

Minor

Intermediate to

moderate

Substantial

Biomedical Research

ICRP and WHO categorization of risk

aTo be kept below deterministic thresholds except for therapeutic experiments.

Part 6. Medical Exposure

research on pregnant patients
Research on Pregnant Patients
  • Radiation research involving pregnant patients should be discouraged

Part 6. Medical Exposure

dose constraints1
Dose Constraints

“3.152. Registrants and licensees shall ensure that no individual incurs a medical exposure as a carer or comforter unless he or she has received, and has indicated an understanding of, relevant information on radiation protection and information on the radiation risks prior to providing care and comfort to an individual undergoing a radiological procedure. Registrants and licensees shall ensure that the requirements specified in para. 3.172 are met for the optimization of protection and safety for any procedure in which an individual acts as a carer or comforter.”

Part 6. Medical Exposure

dose constraints2
Dose Constraints

..The dose shall be constrained so that it is unlikely that his or

her dose will exceed 5 mSv during the period of a patient’s

diagnostic examination or treatment. The dose to children

visiting patients who have ingested radioactive materials should

be similarly constrained to less than 1 mSv

Part 6. Medical Exposure

nm patient with pregnant family member at home
NM patient with pregnant family member at home

For most diagnostic nuclear medicine procedures, the total decay dose at 0.5 meter from the patient ranges from .02-0.25 mGy and at 1 meter from the patient the dose is 0.05-0.10 mGy. This poses no significant risk to pregnant family members.

Part 6. Medical Exposure

part 6 medical exposure protection of the patient6

Part 6. Medical ExposureProtection of the Patient

IAEA Training Material on Radiation Protection in Nuclear Medicine

Module 6.7. Examination of Children, Pregnant and Lactating Women

optimization2
Optimization

“3.165. Registrants and licensees shall ensure that the particular aspects of medical exposures are considered in the optimization process for:

  • (a) Paediatric patients subject to medical exposure;
  • ……..
  • (e) Exposure of the embryo or fetus, in particular for radiological procedures in which the abdomen or pelvis of the pregnant woman is exposed to the useful radiation beam or could otherwise receive a significant dose;
  • (f) Exposure of a breast-fed infant as a result of a female patient undergoing a radiological procedure with radiopharmaceuticals.”

Part 6. Medical Exposure

radiation risks
Radiation Risks

Part 6. Medical Exposure

activity to children
Activity to Children

The amount of activity administered to an adult can for children be reduced by one of the following methods:

  • body weight/70 kg
  • body surface area/1.73 m2
  • height/174 cm

Part 6. Medical Exposure

fraction of the adult activity
Fraction of the Adult Activity

Part 6. Medical Exposure

children

…...noting the special requirements for

Children

Local rules for administered activities to children should be available. Recommendations from international professional organizations should be followed.

Part 6. Medical Exposure

pregnancy
Pregnancy

Part 6. Medical Exposure

slide88

ribs

Fetal skull

Blood outside uterus

Fetal dose 20 mGy

Example of justified use of CT in a pregnant female who was in a motor vehicle accident

Part 6. Medical Exposure

slide89

Free blood

Kidney ripped off aorta (no contrast in it)

Splenic laceration

3 minute CT exam and taken to the operating room. She and the child survived

Part 6. Medical Exposure

introduction
Introduction
  • Thousands of pregnant women are exposed to ionizing radiation each year
  • Lack of knowledge is responsible for great anxiety and probably unnecessary termination of pregnancies
  • For most patients, radiation exposure is medically appropriate and the radiation risk is minimal

Part 6. Medical Exposure

slide91
In some circumstances, the exposure is inappropriate and the unborn child may be at increased risk.
  • Prenatal doses from most properly done diagnostic procedures present no measurably increased risk of prenatal death, malformation, mental impairment.
  • Higher doses such as those from therapeutic procedures can result in significant fetal harm.

Part 6. Medical Exposure

slide92

An example of media nonsense

Part 6. Medical Exposure

pregnant women
Pregnant Women

“3.175. Registrants and licensees shall ensure that there are procedures in place for ascertaining the pregnancy status of a female patient of reproductive capacity before the performance of any radiological procedure that could result in a significant dose to the embryo or fetus, so that this information can be considered in the justification for the radiological procedure (para. 3.154) and in the optimization of protection and safety (para. 3.165).”

Part 6. Medical Exposure

situation analysis
Situation Analysis
  • Number of females getting exposed every week without knowing that they are pregnant:Inadvertentradiation exposure of early conceptus
  • Planned Exposures:
    • patients needing nuclear medicine examinations or even therapy while pregnant
  • Accidentalexposure in pregnancy
  • Occupational exposures in pregnancy
  • Exposure of female of reproductive capacity

Part 6. Medical Exposure

how sensitive is early c onceptus
How Sensitive is Early Conceptus?

Threshold dose

deterministic effects 100 - 200 mSv

Mental retardation 40 % /Sv

Cancer and leukemia

before 10 years of age 2 % /Sv

lifetime 15 % /Sv

Hereditary effects 1 % /Sv

Part 6. Medical Exposure

irradiation of fetus results from
Irradiation of Fetus Results from:
  • Placental transfer
    • distribution of activity in fetal organs
      • not much data available
      • I-131 as iodide Tc-99m pertechnetate
  • External radiation from activity present in the mothers organs and tissues
    • radiopharmaceuticals eliminated via the kidneys

Part 6. Medical Exposure

absorbed dose to the fetus
Absorbed Dose to the Fetus

Examination Activity Dose to fetus

(MBq) (mSv)

Bone (Tc99m) 600 4

Brain (CBF) 500 4

Lung (Tc99m-MAA) 160 0.4

Kidneys (MAG3) 100 2

Tumour or abscess (Ga-67 citrate) 300 28

Heart (Tc99m-MIBI) 300 5

Heart (Tl-201) 100 10

Thyroid (Tc99m) 100 1

Thyroid (I-131) 100 7

Kidney clearance (Cr-51-EDTA) 4 0.02

(Data from Russell, Stabin et al Radiation dose to the embryo/fetus from radiopharmaceuticals Draft, 1997

Part 6. Medical Exposure

absorbed dose to the fetus1
Absorbed Dose to the Fetus

(Data from Russell, Stabin et al Radiation dose to the embryo/fetus from radiopharmaceuticals Draft, 1997

Part 6. Medical Exposure

risk of childhood cancer from mother s diagnostic procedure in nm
Risk of childhood cancer from mother’s diagnostic procedure in NM
  • The risk to an embryo or fetus from absorbing 1 mSv of radiation dose - an increased risk of developing childhood cancer of 6 in 100,000 (3 of which would be fatal)
  • Natural risk of complications of pregnancy or of birth anomalies is approximately 4,000 in 100,000
  • Natural risk of the incidence of childhood cancer – 150 in 100,000
  • Fetal doses from diagnostic procedures in NM – max. tens of mSv ( 67Ga, 131I)

Part 6. Medical Exposure

prevention of inadvertent e xposure in pregnancy
Prevention of Inadvertent Exposure in Pregnancy

When a female of reproductive age presents for an examinationask:

  • Is she likely to be pregnant? Is period over-due?
  • This should be recorded at appropriate place in the form
  • Females under 16?

Depending upon answer

  • No possibility of pregnancy
  • Proceed with the examination

Part 6. Medical Exposure

if you think that you might be pregnant notify staff before treatment
IF YOU THINK THAT YOU MIGHT BE PREGNANT , NOTIFY STAFF BEFORE TREATMENT

Part 6. Medical Exposure

before examination is performed
Before Examination is Performed
  • Many patients incorrectly assume that irradiation from a nuclear medicine examination begins when the gamma camera begins imaging,
  • Therefore, before radiopharmaceutical administration, it is necessary to
  • consider as pregnant any woman of reproductive age presenting for a nuclear medicine examination at a time when a menstrual period is overdue or missed, unless
  • there is information that precludes pregnancy (e.g., hysterectomy or tubal ligation).
  • If the menstrual cycle is irregular, and a non-technetium or therapeutic radiopharmaceutical is being administered, a pregnancy test may be indicated before proceeding.

Part 6. Medical Exposure

informed consent and understanding
Informed Consent and Understanding
  • The pregnant patient has a right to know the magnitude and type of potential radiation effects that might result from in-utero exposure
  • Communication should be related to the level of risk. Verbal communication may be adequate for low dose procedures.
  • If fetal doses are above 1 mGy, usually a more detailed explanation is given

Part 6. Medical Exposure

if an examination of a pregnant woman is judged to be necessary
If an examination of a pregnant woman is judged to be necessary
  • Choice of radiopharmaceutical
  • Is it possible to reduce the administered activity?
  • Prolonged acquisition times?
  • For radiopharmaceuticals eliminated via the kidneys:
    • Partially filled urinary bladder at the time of administration
    • Hydration and frequent voiding

Part 6. Medical Exposure

during the examination
During the Examination

Using smaller administered activities and longer imaging times can reduce the absorbed dose to the fetus. This is feasible if the patient is not too sick and is able to remain still

Part 6. Medical Exposure

during the examination1
During the Examination
  • The sequence of the examinations can be adjusted to reduce radiation dose.
  • e.g. a ventilation-perfusion lung scan ordered on a pregnant patient to exclude a pulmonary embolus.
  • Many laboratories will perform the ventilation scan first and then do the perfusion scan.
  • In the specific case of a suspected pulmonary embolus, the perfusion scan can be performed first, and if it is normal, a ventilation scan is not needed at all.

Part 6. Medical Exposure

during the examination contd
During the Examination (contd.)
  • There will be much smaller fetal dose with Xenon-133
  • If one does ventilation scans using 99mTc-DTPA aerosol, this will be absorbed and excreted via the kidneys, and while in the bladder it will contribute to fetal dose

Part 6. Medical Exposure

dose reduction after procedure has been performed
Dose reduction after procedure has been performed

Can the dose be reduced after the procedure has been performed?

  • Yes, by accelerating voiding, bladder dose
  • Not possible in radiology and RT

Part 6. Medical Exposure

termination of pregnancy
Termination of Pregnancy
  • Termination of pregnancy at fetal doses of less than 100 mGy is NOT justified based upon radiation risk
  • At fetal doses in excess of 100 mGy, there can be fetal damage, the magnitude and type of which is a function of dose and stage of pregnancy
  • In these cases decisions should be based upon individual circumstances

Part 6. Medical Exposure

becoming pregnant after irradiation
Becoming Pregnant after Irradiation
  • ICRP has recommended that a woman not become pregnant until the potential fetal dose fromremaining radionuclides is less than 1 mGy.
  • This is not usually a considerationexcept for radiopharmaceuticals labelled with 59Fe (formetabolism studies) or 75Se (for adrenal imaging).
  • As a result of the long physicalhalf-lives of these radionuclides and their long residence times in the body, it is recommended that pregnancy be avoided for 6 and 12 months respectively.

Part 6. Medical Exposure

mothers in lactation
Mothers in Lactation

Part 6. Medical Exposure

optimization breast feeding
Optimization: Breast Feeding

“3.176. Registrants and licensees shall ensure that there are arrangements in place for establishing that a female patient is not breast-feeding before the performance of any radiological procedure involving the administration of a radiopharmaceutical that could result in a significant dose to an infant being breast-fed, so that this information can be considered in the justification for the radiological procedure (para. 3.154 and 3.156 ) and in the optimization of protection and safety (para. 3.165).”

Part 6. Medical Exposure

irradiation of breastfed child results from
Irradiation of breastfed child results from:
  • Activity in milk
  • External radiation from the mother
  • Possible contamination

Part 6. Medical Exposure

recommendations for cessation of breast feeding

Radiopharmaceutical

Administered activity

Counseling?

Advice

(MBq)

Tc

-

99m DTPA

740

no

Tc

-

99m MAA

148

yes

12 hr

Tc

-

99m Pertechnetate

185

yes

4 hr

Tc

-

99m DISIDA

300

no

Tc

-

99m glucoheptonate

740

no

Tc

-

99m HAM

300

no

Tc

-

99m MIBI

1110

no

Tc

-

99m MD

P

740

no

Recommendations for Cessation of Breast Feeding

Tc

-

99m PYP

740

no

Tc

-

99m RBC\'s in vivo

740

yes

12 hr

labelling

Tc

-

99m RBC\'s in vitro

740

no

labelling

Tc

-

99m Sulphur Colloid

444

no

Tc

-

99m DTPA Aerosol

37

no

Tc

-

99m WBC\'s

185

yes

48 hr

Tc

-

99m MAG3

370

no

Part 6. Medical Exposure

recommendations for cessation of breast feeding1

Radiopharmaceutical

Adminis

tered activity

Counseling?

Advice

(MBq)

Ga

-

67 Citrate

185

yes

Cessation

I

-

131 NaI

5550

yes

Cessation

Cr

-

51 EDTA

1.85

no

In

-

111 WBC\'s

20

n

o

I

-

123 NaI

15

y

es

Cessation

I

-

123 OIH

74

n

o

I

-

123 mIBG

370

y

es

48 hr

I

-

125 OIH

0.37

Recommendations for Cessation of Breast Feeding

n

o

I

-

131 OIH

11.1

n

o

Tl

-

201

111

y

es

96 hr

Xe

-

133 gas

n

o

Part 6. Medical Exposure

part 6 medical exposure protection of the patient7

Part 6. Medical ExposureProtection of the Patient

IAEA Training Material on Radiation Protection in Nuclear Medicine

Module 6.8. Records

records
Records
  • “3.182. Registrants and licensees shall maintain for a period as specified by the regulatory body and shall make available, as required, the following personnel records:
    • (a) Records of any delegation of responsibilities by principal parties (as required in para. 3.153(f));
    • Records of training of personnel in radiation protection (as required in para. 3.149(b)).
  • 3.183. Registrants and licensees shall maintain for a period as specified by the regulatory body and shall make available, as required, the following records of calibration, dosimetry and quality assurance:
    • (a) Records of the results of the calibrations and periodic checks of the relevant physical and clinical parameters selected during treatment of patients;
    • (b) Records of dosimetry of patients, as required in para. 3.167;
    • (c) Records of local assessments and reviews made with regard to diagnostic reference levels, as required in para. 3.168;
    • (d) Records associated with the quality assurance programme, as required in para. 3.170(d).”

Part 6. Medical Exposure

records1
Records
  • “3.184. Registrants and licensees shall maintain for a period as specified by the regulatory body and shall make available, as required, the following records for medical exposure:
    • …….
    • (c) For nuclear medicine, the types of radiopharmaceutical administered and their activity;
    • …….
    • (e) Exposure records for volunteers subject to medical exposure as part of a programme of biomedical research;
    • (f) Reports on investigations of unintended and accidental medical exposures (as required in para. 3.180(d).”

Part 6. Medical Exposure

records and documents medical exposures
Records and Documents:Medical Exposures
  • Administered radiopharmaceutical
  • and activity (each patient)
  • Route of administration (each patient)
  • Incident and accident investigation reports
  • Absorbed doses to patients
  • Calibration certificate (activity meter)
  • Quality control of equipment
  • (gamma camera & activity meter)
  • Maintenance and repair work
  • Audits and reviews of radiation safety programme
  • Training provided:
  • initial
  • refresher

Part 6. Medical Exposure

part 6 medical exposure protection of the patient8

Part 6. Medical ExposureProtection of the Patient

IAEA Training Material on Radiation Protection in Nuclear Medicine

Module 6.9. Local Rules

local rules medical exposures
Local Rules:Medical Exposures

Activity to adults in nuclear medicine examinations

Activity to children in nuclear medicine examinations

Rules for pregnant women

Rules for lactating women

Preparation and dispensation of radiopharmaceuticals

Procedure manual, activity meter

Patient identification and information

Administration of radiopharmaceuticals

Procedure manual, gamma camera examinations

Procedures in case of misadministrations

Procedures in case of accidents

Records

Part 6. Medical Exposure

local rules
Local Rules

Department of Nuclear Medicine

Radiation Protection Manual

PROTECTION OF THE PATIENT

Activity to Adults

Children & Young people

Pregnant women

Lactating women

Radiopharmaceuticals

Activity measurement

Misadministration

Examination

Proceedure Manuals

Patient Identification

Part 6. Medical Exposure

slide125

Questions?

Part 6. Medical Exposure

disccussion
Disccussion
  • Increase the activity for elderly patients and patients with pain to reduce the examination time?
  • Increase the activity for all patients in order to increase the throughput of patients?
  • Increase the activity for paediatric patients in order to avoid sedation or general anaesthesia?
  • Increase the activity to cancer patients who are nevertheless going to receive radiotherapy?

Part 6. Medical Exposure

discussion
Discussion

A patient is referred to a bone scan. It is obvious from the information on the request that this is the wrong type of examination to get the right diagnosis. The examination is done anyway. Who is responsible for this non justified exposure?

Part 6. Medical Exposure

discussion1
Discussion

Discuss how to handle the problem when it isnecessary to to examine or treat a woman who is pregnant.

Part 6. Medical Exposure

where to get more information
Where to Get More Information
  • Other sessions
    • Part 7 Optimization of protection in Nuclear Medicine Examinations
    • Part 8 Optimization of protection in Nuclear Medicine therapy
    • Part 11 Potential exposure and accidental medical exposure
  • Further readings
    • IAEA Basic Safety Standards: Interim Edition (2011)
    • IAEA Safety Guide on Radiological Protection for Medical Exposure
    • IAEA Model regulations on radiation safety in nuclear medicine
    • WHO. Manual on Radiation Protection in Hospitals and General Practices. Volume 4: Nuclear Medicine
    • ICRP publication 84
  • Practical session
    • Simulated inspection

Part 6. Medical Exposure

local rules 1
Local Rules 1

Department of Nuclear Medicine

Radiation Protection Manual

PROTECTION OF THE PATIENT

ADULTS

Note: For not listed examinations consult the nuclear medicine specialist

Part 6. Medical Exposure

local rules 2
Local Rules 2

Department of Nuclear Medicine

Radiation Protection Manual

PROTECTION OF THE PATIENT

CHILDREN & YOUNG PEOPLE

Note: For not listed examinations consult the nuclear medicine specialist

Part 6. Medical Exposure

local rules 3
Local Rules 3

Department of Nuclear Medicine

Radiation Protection Manual

PROTECTION OF THE PATIENT

PREGNANT WOMEN

  • If a female patient is pregnant or think that she might be, the responsible physician shall always make a decision whether the examination shall be done or shall be postponed either until after delivery or to the latter half of the pregnancy, carefully considering the use of other diagnostic methods.
  • If there is uncertainty concerning pregnancy, either because the period is known to be overdue or for other reasons, the woman shall be treated as pregnant until otherwise proved.
  • The administered activity shall be in proportion to body weight using 70% of the normal adult activity for the required examination

Part 6. Medical Exposure

local rules 4
Local Rules 4

Department of Nuclear Medicine

Radiation Protection Manual

PROTECTION OF THE PATIENT

LACTATING WOMEN

No counseling of breastfeeding for the following radiopharmaceuticals:

51Cr-EDTA, 99mTc-DMSA, 99mTc-DTPA, 99mTc-MDP, 99mTc-glycoheptonate

99mTc-HMPAO, 99mTc-MIBI, 99mTc-colloids, 99mTc-MAG3(<100MBq),

201Tl-chloride (<80MBq) and 111In-leucocytes (<20MBq).

For other radiopharmaceuticals, see attached

For not listed radiopharmaceuticals, consult the nuclear medicine specialist

table

Part 6. Medical Exposure

local rules 4 1
Local Rules 4:1

Department of Nuclear Medicine

Radiation Protection Manual

PROTECTION OF THE PATIENT

LACTATING WOMEN

Counseling of breastfeeding

Part 6. Medical Exposure

local rules 5
Local Rules 5

Department of Nuclear Medicine

Radiation Protection Manual

PROTECTION OF THE PATIENT

RADIOPHARMACEUTICALS

Preparation

Dispensing

Injection

Part 6. Medical Exposure

local rules 5 1
Local Rules 5:1

Department of Nuclear Medicine

Radiation Protection Manual

PROTECTION OF THE PATIENT

PREPARATION OF RADIOPHARMACEUTICALS

Name: DPD (CIS bio)

Composition13 mg 3,3-diphosphono-1,2-propanedicarboxylic acid, tetrasodium salt (DPD) 0.23 mg

tin(II)oxide

Usage: Bone scintigraphy

Preparation: Use a transparent vial shield. Put the kit vial in the shield. Dispense 5 ml pertechnetate

(3000 MBq) in a shielded syringe. Add the solution to the vial containing the freeze dried

kit.

Remove an equal volume of gas to equalize the pressure. Shake the vial gently for 10 s.

Store the preparation for 5 min. Temporarily remove the vial from the shield and measure

the activity.

Use a forceps when moving thevial. Put a label on the shield. The label shall contain: Name

of radiopharmaceutical, activity andactivity concentration as well as date and time. Check

the label against the vial. Same radiopharmaceutical? Record the preparation and sign.

The preparation can be used for 5 patientexaminations within 6 h from time of

preparation.  

Storage: Kit in fridge

Radiopharmaceutical in the shielded container and protected from light

Part 6. Medical Exposure

local rules 5 2
Local Rules 5:2

Department of Nuclear Medicine

Radiation Protection Manual

PROTECTION OF THE PATIENT

DISPENSING RADIOPHARMACEUTICALS

  • Check the label on the vial shield. Is it the required radiopharmaceutical?
  • Calculate the volume to dispense from the decay corrected activity concentration and the requested activity for the intended examination.
  • Dispense the calculated volume using a shielded syringe.
  • Temporarily remove the syringe shield and measure the activity.
  • Write a label and put it on the syringe shield. The label shall contain patient name and id number, radiopharmaceutical, activity, date and time. The label shall be signed.

Part 6. Medical Exposure

local rules 5 3
Local Rules 5:3

Department of Nuclear Medicine

Radiation Protection Manual

PROTECTION OF THE PATIENT

IDENTIFICATION OF PATIENT

INJECTION OF RADIOPHARMACEUTICALS

  • Ask the patient about name and birth date or identification number.
  • Ask a female patient about pregnancy.
  • Ask a female patient if she is breastfeeding a child.
  • If necessary, inform the patient about any restrictions according to the local rules.
  • Read the request
  • Check the label on the syringe shield.
  • Is it the correct radiopharmaceutical and activity for the requested examination?
  • Inject according to the local rules for intravenous injections
  • The radiopharmaceutical and the injected activity.shall be recorded

Part 6. Medical Exposure

local rules 6
Local Rules 6

Department of Nuclear Medicine

Radiation Protection Manual

PROTECTION OF THE PATIENT

ACTIVITY MEASUREMENT

  • The activity of the radiopharmaceutical shall always be measured after
  • preparation and before and after injection.
  • Select the isotope
  • Check the background reading and make a background adjustment
  • Put the syringe or the vial in the holder using a forceps
  • Put the holder into the chamber
  • Read the activity
  • Remove the holder and put the syringe or vial back into the shield

Part 6. Medical Exposure

local rules 7
Local Rules 7

Department of Nuclear Medicine

Radiation Protection Manual

PROTECTION OF THE PATIENT

MISADMINISTRATION

The following are defined as misadministrations: Administration to the wrong patient, administration of the wrong radiopharmaceutical, administration of wrong activity (>15% from prescribed activity in therapy and >75% in diagnostic examinations) and wrong route of administration.

  • In case of misadministration:
  • Inform the nuclear medicine specialist
  • Inform the patient and the referring physician
  • Inform the medical physicist (phone ……), who shall calculate and report the patient dose
  • The responsible technician shall write a report about the event and try to explain the causes.
  • The nuclear medicine specialist shall send the report to the Head of the Department who shall decide if the event shall be reported to the authorities.
  • All members of the staff shall be informed

Part 6. Medical Exposure

local rules 8
Local Rules 8

Department of Nuclear Medicine

Radiation Protection Manual

PROTECTION OF THE PATIENT

Study name: Bone scan

Preparation of patient: Empty bladder

Radiopharmaceutical: Tc99m-DPD

Route of administration: iv injection

Activity: 400 MBq

Start of measurement: 3h post injection

Type of examination: Whole body scan

Views: AP, PA

Scanning speed: 10 cm/min

Collimator: LEHR

Window setting: 140+/-20% keV

Positioning of patient: Supine

Presentation of result: Images in BW on film.

Part 6. Medical Exposure

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