Florida Chapter of the Health Physics SocietySpring 2016 Technical Meeting01 April 2016

RADIOACTIVE PATIENT RELEASEGlenn M. Sturchio, PhD, CHPMayo Clinic in Jacksonville[Jeffrey J. Brunette, CHP; Mayo Clinic in Rochester]

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Today’s Journey

©2011 MFME

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NCRP Program Area Committee 2: Operational Radiation Safety

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Background Radiation

NCRP Report 160

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Adult Effective Doses for Various CT Procedures

Radiology: Vol 248: Number 1 – July 2008

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Adult Effective Doses for Various Interventional Radiology Procedures

Radiology: Vol 248: Number 1 – July 2008

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Effective Doses for Adults from Various Nuclear Medicine Examinations

Radiology: Vol 248: Number 1 – July 2008

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Effective Doses for Adults from Various Nuclear Medicine Examinations

Radiology: Vol 248: Number 1 – July 2008

= 20 mCi

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Effective Doses for Adults from Various Nuclear Medicine Examinations

Radiology: Vol 248: Number 1 – July 2008

= 20 mCi

= 30 mCi

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Effective Doses for Adults from Various Nuclear Medicine Examinations

Radiology: Vol 248: Number 1 – July 2008

= 20 mCi

= 30 mCi

= 30 mCi

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10 CFR 35.75, Release of Individuals …

Outpatient or Inpatient

Patient-Specific

Dose Calculation

Measured Dose Rate

Administered Activity

NUREG-1556, Vol 9, Rev 2

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Activities and Dose Rates for Patient Release

RadionuclideActivity At or Below

Which Patient may BeReleased (mCi)

Dose Rate @ 1mAt or Below Which

Patient may BeReleased (mrem/h)

I-131 33 7Tc-99m 760 58

F-18 330 185Y-90 ** **

NUREG-1556, Vol 9, Rev 2

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Effective Doses for Adults from Various Nuclear Medicine Examinations

Radiology: Vol 248: Number 1 – July 2008

= 20 mCi

= 30 mCi

= 30 mCi

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Mayo Clinic in RochesterWhere Radioiodine Patients Come From?

52% within 100 miles.

15% within 100 - 250 miles21% within 250 – 500 miles 9% could drive, > 500 miles, and

3% international

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So How Do We Get These People Home?

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Wheel of Fortune?

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Eligibility

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Retained 131I

Med Phys 42(4), April 2015

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10 CFR 35.75, Release of Individuals …

Outpatient or Inpatient

Patient-Specific

Dose Calculation

Measured Dose Rate

Administered Activity

NUREG-1556, Vol 9, Rev 2

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Our Approach• Start with the NRC calculation model

• Add a number of improvements

• Revise equations to “compartmentalize” calculation

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NRC Calculation Model • From NUREG 1556, vol. 9, Appendix U:

• where, Fi, Ti are uptake and effective half-lives, Γ is the gamma constant, Q0 is administered activity, d is the distance, and Tp is physical half-life.

𝐃𝐃 ∞

=𝟑𝟑𝟑𝟑.𝟔𝟔 𝚪𝚪 𝐐𝐐𝟎𝟎

𝐝𝐝𝟐𝟐�𝐄𝐄𝟏𝟏𝐓𝐓𝐏𝐏(𝟎𝟎.𝟖𝟖) 𝟏𝟏 − 𝐞𝐞−𝟎𝟎.𝟔𝟔𝟔𝟔𝟑𝟑 𝐓𝐓𝐍𝐍𝐍𝐍 /𝐓𝐓𝐏𝐏

+ 𝐄𝐄𝟐𝟐𝐞𝐞−𝟎𝟎.𝟔𝟔𝟔𝟔𝟑𝟑(𝐓𝐓𝐍𝐍𝐍𝐍)/𝐓𝐓𝐏𝐏�𝐅𝐅𝟏𝟏𝐓𝐓𝟏𝟏 𝟏𝟏 − 𝐞𝐞−𝟎𝟎.𝟔𝟔𝟔𝟔𝟑𝟑(𝐭𝐭−𝐓𝐓𝐍𝐍𝐍𝐍)/𝐓𝐓𝟏𝟏

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Revisions to NRC Calculations• Account for self-shielding

In post-thyroidectomy thyroid carcinoma, self-shielding: Γ = 1.7 R-cm2/mCi-hr1

• Non-voiding time NRC uses 8 hours. NCRP uses rapid uptake and 3.5 hour voiding in

dosimetry calculations. Others suggest using 1 hour. We chose 3.5 hours and eliminated the “0.8” factor

that the NRC uses.

1 K. Nelson measurements and Carey JE, et. al., Release of Patients Containing Therapeutic Doses of Iodine-131 from Hospitals. J Nucl Med Technol 23:144-149; 1995.

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Revisions to NRC Calculations• Occupancy

E = 1 while in transit E = 0.25 at all other times

• Distance d = 1 meter most of the time (instructions), Car distances measured, d = 1 meter in car

(instructions to sit as far apart as possible)2, Air travel distances, d = 0.6 meter.

2 J. Brunette measurements in a variety of vehicle types. Excludes motorcycles and mini-vehicles (Smart Car / 2-seater vehicles)..

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Revisions to NRC Calculations• Limit on radiation dose:

5 mSv (0.5 rem) to adult care-giver accompanying patient on travel home, and

1 mSv (0.1 rem) to others encountered during travel home.

• Equations split into components for: Dose during “pre-travel phase”, Dose during “travel phase”, and Dose during “post-travel phase”.

.

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Revised Equations• Example (assumes immediate travel home by car):

• where,

.

𝐃𝐃 ∞ = 𝐃𝐃 𝐫𝐫𝐫𝐫𝐝𝐝𝐫𝐫𝐫𝐫𝐫𝐫 𝐫𝐫𝐫𝐫 𝐜𝐜𝐜𝐜𝐫𝐫 + 𝐃𝐃(𝐩𝐩𝐩𝐩𝐩𝐩𝐭𝐭 𝐭𝐭𝐫𝐫𝐜𝐜𝐭𝐭𝐞𝐞𝐭𝐭 / 𝐜𝐜𝐭𝐭 𝐡𝐡𝐩𝐩𝐡𝐡𝐞𝐞)

𝐃𝐃 𝐫𝐫𝐫𝐫𝐝𝐝𝐫𝐫𝐫𝐫𝐫𝐫 𝐫𝐫𝐫𝐫 𝐜𝐜𝐜𝐜𝐫𝐫

=𝟑𝟑𝟑𝟑.𝟔𝟔 𝚪𝚪 𝐐𝐐𝟎𝟎

𝐝𝐝𝟐𝟐�𝐄𝐄𝐓𝐓𝐓𝐓𝐏𝐏 𝟏𝟏 − 𝐞𝐞−𝟎𝟎.𝟔𝟔𝟔𝟔𝟑𝟑 𝐓𝐓𝐍𝐍𝐍𝐍 /𝐓𝐓𝐏𝐏

+ 𝐄𝐄𝐓𝐓𝐞𝐞−𝟎𝟎.𝟔𝟔𝟔𝟔𝟑𝟑(𝐓𝐓𝐍𝐍𝐍𝐍)/𝐓𝐓𝐏𝐏�𝐅𝐅𝟏𝟏𝐓𝐓𝟏𝟏 𝟏𝟏 − 𝐞𝐞−𝟎𝟎.𝟔𝟔𝟔𝟔𝟑𝟑(𝐭𝐭−𝐓𝐓𝐍𝐍𝐍𝐍)/𝐓𝐓𝟏𝟏

𝐃𝐃 𝐩𝐩𝐩𝐩𝐩𝐩𝐭𝐭 𝐭𝐭𝐫𝐫𝐜𝐜𝐭𝐭𝐞𝐞𝐭𝐭/𝐜𝐜𝐭𝐭 𝐡𝐡𝐩𝐩𝐡𝐡𝐞𝐞

=𝟑𝟑𝟑𝟑.𝟔𝟔 𝚪𝚪 𝐐𝐐𝟎𝟎

𝐝𝐝𝟐𝟐�𝐄𝐄𝟐𝟐𝐞𝐞−𝟎𝟎.𝟔𝟔𝟔𝟔𝟑𝟑(𝐓𝐓𝐍𝐍𝐍𝐍)/𝐓𝐓𝐏𝐏�𝐅𝐅𝟏𝟏𝐓𝐓𝟏𝟏 𝐞𝐞−𝟎𝟎.𝟔𝟔𝟔𝟔𝟑𝟑(𝐭𝐭−𝐓𝐓𝐍𝐍𝐍𝐍)/𝐓𝐓𝟏𝟏

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You possessed of sturdy intellects, observe the teaching that is hidden here beneath the veil of verses so obscure

- Dante, Inferno, Canto IX, 61-64

©2011 MFMER |

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Picano E BMJ 2004;329:849-851

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Results of EvaluationCar Travel Time to Reach 5 mSv doseCondition Max Activity Max Car Travel Time

Hyperthyroidism Up to 33 mCi 72 hours*

Post-thyroidectomy thyroid carcinoma

150 mCi 24 hours

160 mCi 17 hours

170 mCi 13 hours

180 mCi 10 hours

190 mCi 8 hours

200 mCi 7 hours

* We only allow up to 24 hour car travel.

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ResultsAir Travel Hyperthyroidism – 1 mSv External Dose

Maximum Air Travel Time Permissible With:

Max Activity No Delay One Day Delay Two Days Delay

10 mCi > 24 hours NA NA

15 mCi 15 hours 20 hours >24 hours

20 mCi 11 hours 15 hours 17 hours

25 mCi 8 hours 12 hours 14 hours

33 mCi 9 hours 10 hours 12 hours

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ResultsAir Travel Post-thyroidectomy Thyroid Carcinoma – 1 mSv External Dose

Maximum Air Travel Time Permissible With:

Max Activity No Delay One Day Delay Two Days Delay

150 mCi 1 hour 9 hours >24 hours

160 mCi 1 hour 9 hours >24 hours

170 mCi 1 hour 8 hours >24 hours

180 mCi 1 hour 7 hours >24 hours

190 mCi 1 hour 7 hours >24 hours

200 mCi 1 hour 6 hours 23 hours

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Patient Instructions (>33 mCi 131I)

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HPS PS027-0

RELEASE OF PATIENTS TREATED WITH

THERAPEUTIC QUANTITIES OF

RADIOPHARMACEUTICALS AND SEALED SOURCES

POSITION STATEMENT OF THE HEALTH

PHYSICS SOCIETY

March 2012

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HPS PS027-0

Algorithms recommended in NRC guidance … are conservative in overestimating those doses

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HPS PS027-0

Studies measuring dose to family members … have demonstrated that actual doses received are small and well below the patient release dose criteria.

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HPS PS027-0

The Health Physics Society maintains that release of patients … poses no discernible risk to the public … and provides significant benefits to patients, their families, and society.

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SAFETY©2011 MFMER |

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