Mammography facilities are required to provide patients with a “lay report” - what is it? - when does it need to be provided?

- written results of the mammogram in language that is easy to understand. - within 30 DAYS of the study (MUST).

Physics Flashcards by Stephen Malutich

Appropriate target range for medical audit:

Recall rate?

4-7%

My note: Prometheus says 4-7 in one place, 5-7 in another, and “less than 10%” in another.

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Appropriate target range for medical audit:

Cancers/1000 screened?

3-8

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How often:

Processor QC

Daily

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How often:

Darkroom Cleanliness

Daily

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How often:

Viewbox Conditions?

Weekly

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How often:

Phantom Evaluation?

Weekly

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How often:

Repeat Analysis?

Quarterly

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How often:

Compression Test?

Semi-Annually

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How often:

Darkroom Fog?

Semi-Annually

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How often:

Screen-Film Contrast?

Semi-Annually

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Places that do mammo have to be “accredited and certified”…..and pay money…. every _________.

3 years

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_______ is the evil overlord begins the MQSA.

The FDA

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Gaining the privilege to read mammograms: 3 criteria you must meet

1) read 240 mammography exams over 6 months during last 2 years of training, under direct supervision,
2) 3 months of mammography in residency,
3) 60 documented hours of mammo education

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Spatial Resolution (mammo):

LP/mm in Anode-Cathode Direction ?

13 LP/mm

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Spatial Resolution (mammo):

LP/mm in left-right Direction ?

11 LP/mm

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Spatial Resolution (mammo):

MQSA resolution for screen-film: _____

12 LP/mm

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Spatial Resolution (mammo):

MQSA resolution for digital: _____

Manufacturer specs (~ 7 LP/mm)

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What is the MQSA breast dose phantom?

MQSA has breast phantom which is supposed to be an “average breast.”

4.2 cm of compressed breast
50% adipose, 50% glandular.

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Dose for MQSA phantom

Phantom limit (per image)=

3 mGy (300 millirads) WITH GRID

1 mGy WITHOUT GRID.

Note: Dose limit ONLY for phantom!!! There is no regulation for dose to real human breast.

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How Often:

Localization/Accuracy (for Stereotactic Biopsy)?

Daily before patient exams

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Mammography facilities are required to provide patients with a “lay report”

what is it?
when does it need to be provided?

written results of the mammogram in language that is easy to understand.
within 30 DAYS of the study (MUST).

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Consumer complaint mechanism is required to be established in mammography facilities to provide patients with a process for addressing their concerns.

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Patients can have their ORIGINAL mammograms (not just copies) when they are needed.

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If a facilities mammograms are determined to be substandard and a risk to public health, what happens?

Those FACILITIES will notify patients and their doctors and suggest an appropriate plan of action.

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Who is ultimately responsible for the Quality Control program?

The “INTERPRETING PHYSICIAN” | Not the techs.

To make it (the phantom?) pass image quality, must show: _____(4 distinct things)

- 4 fibers - 3 microcalcification clusters, - 3 masses - only “acceptable artifacts”

Patient dose limit in mammography

THERE IS NONE! Only a dose limit for phantom (3 mGy/view). But a denser real breast could require more than 3 mGy/view.

Typical patient and phantom doses (not limits).

~2 mGy/view | ~4 mGy for a two-view screening exam

Typical (average) compressed breast is _______ cm, _______ % glandularity.

6cm, 15-20%

Digital systems generally use higher beam quality, which results in ______ doses.

Lower

Digital mammography does NOT use fixed dose (screen-film). Can use as much or as little radiation as deem appropriate.

Nukes QC: how often to check... Constancy (And “Dose should be within ___% of computed activity.”)

Daily | 5% of computed activity Checked with reference sources

Nukes QC: how often to check... Linearity

Quarterly

Nukes QC: how often to check... Accuracy

At installation of device AND | Annually

Nukes QC: how often to check... Geometry

At installation of device AND | Any time you move device

Does it affect Spatial resolution or Contrast resolution?: Focal spot

Spatial | Smaller spot= better

Does it affect Spatial resolution or Contrast resolution?: Detector Width

Spatial | Smaller detector = better

Does it affect Spatial resolution or Contrast resolution?: Nyquist Limitations “Sampling”

Spatial | Oversampling = better

Does it affect Spatial resolution or Contrast resolution?: Reconstruction Filter

Spatial | Ex: bone “sharp” algorithm gives a higher spatial resolution.

Does it affect Spatial resolution or Contrast resolution?: Number of x-rays (mAs, kV, pitch)

Contrast | More dose—less mottle—will improve contrast resolution

Does it affect Spatial resolution or Contrast resolution?: Slice thickness

Contrast | Thicker = more x-ray quanta = less noise

Does it affect Spatial resolution or Contrast resolution?: Reconstruction Method

Contrast | Iterative > Filtered Back

Does it affect Spatial resolution or Contrast resolution?: Reconstruction Filter

Contrast | Soft tissue > bone

# Choose Increase or Decrease for all: Holding matrix size constant and DECREASING FOV will _______ pixel size. This will _______ spatial resolution, and _______ contrast resolution.

DECREASE pixel size INCREASE spatial resolution DECREASE contrast resolution (Less photons per box)

# Choose Increase or Decrease for all: Holding matrix size constant and INCREASING FOV will _______ pixel size. This will _______ spatial resolution, and _______ contrast resolution.

INCREASE pixel size DECREASE spatial resolution INCREASE contrast resolution (More photons per box)

Will it improve Axial, Lateral, or Elevation Resolution?: Shorter pulses

Axial | Smaller spatial pulse length

Will it improve Axial, Lateral, or Elevation Resolution?: Greater Damping “Low Q”

Axial | Shorter pulses

Will it improve Axial, Lateral, or Elevation Resolution?: Higher frequency

Axial | Shorter wavelength

Will it improve Axial, Lateral, or Elevation Resolution?: Narrowing the beam in the proximal field (adding an acoustic lens). Minimal necessary gain (gain widens the beam). I.e. “Put the thing you want to look at in the focal zone.”

Lateral

Will it improve Axial, Lateral, or Elevation Resolution?: Phased array with multiple focal zones

Lateral

Will it improve Axial, Lateral, or Elevation Resolution?: Increasing the “line density” or lines per cm

Lateral

Will it improve Axial, Lateral, or Elevation Resolution?: Use fixed focal length across the entire surface of the array (downside is partial volume effects)

Elevation

Will it improve Axial, Lateral, or Elevation Resolution?: Minimize slice thickness— done by phase excitation of the outer to inner arrays

Elevation

Axial Resolution is dependent on ________

Spatial Pulse Length

Lateral Resolution is dependent on ________

Transducer Element WIDTH

Elevation Resolution is dependent on ________

Transducer element HEIGHT

Artifacts: Reverberation—what causes it?

Two parallel highly reflective surfaces | My note: looks like description might have been cut off. May want to double check not missing something

Artifacts: Comet tail—what causes it?

Two parallel highly reflective surfaces —closer together (<1/2 SPL)

Artifacts: Ring Down Artifact —what causes it?

Fluid trapped between tetrahedron of air bubbles

Artifacts: Mirror Image—what causes it?

Trapped behind a strong reflector | My note: not sure this is complete...

Artifacts: Reverberation—what does it look like?

Multiple equidistantly spaced linear reflections.

Artifacts: Comet tail—what does it look like?

Triangle (comet) shaped...

Artifacts: Ring Down Artifact—what does it look like?

Parallel band extending posterior to a collection of gas

Artifacts: Mirror image—what does it look like?

This is almost always shown with the liver on lung.

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification: Thicker Slices - Signal to Noise - Spatial Resolution - Duration of Exam

INCREASED signal to noise, DECREASED spatial resolution, NO EFFECT on duration of exam

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification: Larger Field of View - Signal to Noise - Spatial Resolution - Duration of Exam

INCREASED signal to noise, DECREASED spatial resolution, NO EFFECT on duration of exam

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification: Larger Matrix - Signal to Noise - Spatial Resolution - Duration of Exam

DECREASED signal to noise, INCREASED spatial resolution, INCREASED duration of exam

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification: Greater Field Strength - Signal to Noise - Spatial Resolution - Duration of Exam

INCREASED signal to noise NO EFFECT on spatial resolution NO EFFECT on duration of exam

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification: Greater Receiver Bandwidth - Signal to Noise - Spatial Resolution - Duration of Exam

DECREASED signal to noise NO EFFECT on spatial Resolution DECREASED duration of exam

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification: Greater Transmit Bandwidth - Signal to Noise - Spatial Resolution - Duration of Exam

INCREASED signal to noise, DECREASED spatial resolution, NO EFFECT on duration of exam

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification: More Excitations per Slice - Signal to Noise - Spatial Resolution - Duration of Exam

INCREASED signal to noise, NO EFFECT spatial resolution, INCREASED duration of exam

MRI: Choose Increased, Decreased, or No Effect for each category when you have the following modification: Utilizing Partial K Space Sampling - Signal to Noise - Spatial Resolution - Duration of Exam

DECREASED signal to noise NO EFFECT on spatial resolution DECREASED duration of exam

Artifact: Aliasing Direction?

Phase encoding

Artifact: Chemical Shift Direction?

Frequency encoding

Artifact: Gibbs/Truncation Direction?

Both phase AND frequency encoding

Artifact: Motion Artifact Direction?

Phase encoding

Artifact: Zipper Direction?

Phase encoding

Artifact: Aliasing Does it make it better or worse if you Increase the field of view?

Better

Artifact: Aliasing Does it make it better or worse if you Change the phase encoding direction

Better

Artifact: Aliasing Does it make it better or worse if you Smaller FOVs

Worse!

Artifact: Chemical Shift Does it make it better or worse if you Bigger Pixels

Better

Artifact: Chemical Shift Does it make it better or worse if you Fat suppression

Better

Artifact: Chemical Shift Does it make it better or worse if you Increase Receiver Bandwidth

Better

Artifact: Chemical Shift Does it make it better or worse if you Stronger magnetic field

Worse!

Artifact: Chemical Shift Does it make it better or worse if you Lower receiver bandwidth

Worse!

Artifact: Gibbs/Truncation Does it make it better or worse if you Bigger matrix

Better

Artifact: Gibbs/Truncation Does it make it better or worse if you Decrease bandwidth

Better

Artifact: Gibbs/Truncation Does it make it better or worse if you Decrease pixel size (increase PE Steps, decrease FOV)

Better

Artifact: Partial Volume Does it make it better or worse if you Decrease pixel size (increase PE Steps, decrease FOV)

Better

Artifact: Partial Volume Does it make it better or worse if you Thicker slices

Worse!

Artifact: Motion Artifact Does it make it better or worse if you Saturation pulses

Better

Artifact: Motion Artifact Does it make it better or worse if you Respiratory gating

Better

Artifact: Motion Artifact Does it make it better or worse if you Faster sequences (BLADE, PROPELLER)

Better

Artifact: Cross Talk Does it make it better or worse if you Increase slice gap

Better

Artifact: Cross Talk Does it make it better or worse if you Interleave slices

Better

Artifact: Field Inhomogeneity Does it make it better or worse if you Shimming

Better

Artifact: Field Inhomogeneity Does it make it better or worse if you GRE Sequences

Worse!

Artifact: Susceptibility Does it make it better or worse if you GRE Sequences

Worse!

Artifact: Eddy Current Does it make it better or worse if you Optimize sequence of gradient pulses

Better

Artifact: Eddy Current Does it make it better or worse if you DWI-large gradient changes

Worse!

Artifact: Dielectric Effects Does it make it better or worse if you Parallel transmit

Better

Artifact: Dielectric Effects Does it make it better or worse if you Use 1.5T

Better

Artifact: Dielectric Effects Does it make it better or worse if you 3T

Worse!

Artifact: Magic Angle Does it make it better or worse if you T2

Better

Artifact: Magic Angle Does it make it better or worse if you T1, PD

Worse!

Artifact: Magic Angle Cause?

Occurs at 55 degrees

Artifact: Dielectric effects Cause?

Standing waves created as radiowave approaches length of body part (My note: unclear if this is a cause or just trivia...they share a box in chart.)

Artifact: Eddy Current Cause?

Caused by geometric distortion or non-uniformity

Artifact: Susceptibility Cause?

Augmentation of magnetic field. | Trivia: very bad in EPI

Artifact: Field Inhomogeneity Cause?

Geometric distortion

Artifact: Zipper Cause?

Poor shielding

Artifact: Cross Talk Cause?

Overlap of slices

Artifact: Gibbs/Truncation Cause?

Limited sample of FID

Artifact: Gibbs/Truncation Classic location?

Spinal cord

Artifact: Chemical Shift Cause?

Differences in resonance frequencies

Artifact: Aliasing Cause?

A small FOV

Major spill, how much is it?: Tc-99m

100 mCi [100 mCi : Tc99m, Tl-201; 10 mCi: In-111, Ga-67; 1 mCi: I-131 ]

Major spill, how much is it?: Tl-201

100 mCi [100 mCi : Tc99m, Tl-201; 10 mCi: In-111, Ga-67; 1 mCi: I-131 ]

Major spill, how much is it?: In-111

10 mCi [100 mCi : Tc99m, Tl-201; 10 mCi: In-111, Ga-67; 1 mCi: I-131 ]

Major spill, how much is it?: Ga-67

10 mCi [100 mCi : Tc99m, Tl-201; 10 mCi: In-111, Ga-67; 1 mCi: I-131 ]

Major spill, how much is it?: I-131

1 mCi [100 mCi : Tc99m, Tl-201; 10 mCi: In-111, Ga-67; 1 mCi: I-131 ]

Radionuclide Purity (Tc): - what is it? - how is it tested?

What: “How much Mo in the Tc?” Tested: in a dose calibrator with lead shields

Chemical Purity (Tc): - what is it? - how is it tested?

What: how much Al in the Tc? Tested: with pH paper

Radiochemical Purity (Tc): - what is it? - how is it tested?

What: How much free Tc? Tested: thin layer chromatography

Acute Radiation Syndrome: Bone marrow—dose needed?

>2 Gy [ Bone Marrow: >2 Gy, 1-6 wk latent period, Can live.]

Acute Radiation Syndrome: Bone marrow—latent period?

1-6 weeks [Bone Marrow: >2 Gy, 1-6 wk latent period, Can live.]

Acute Radiation Syndrome: Bone marrow—outcome?

Worse with higher dose. It’s possible to survive. [Bone Marrow: >2 Gy, 1-6 wk latent period, Can live.]

Acute Radiation Syndrome: GI—dose needed?

> 8 Gy [GI: > 8 Gy, 5-7 day latent period, death within 2 weeks.]

Acute Radiation Syndrome: GI—latent period?

5-7 days [GI: > 8 Gy, 5-7 day latent period, death within 2 weeks.]

Acute Radiation Syndrome: GI—outcome?

Death with 2 weeks [GI: > 8 Gy, 5-7 day latent period, death within 2 weeks.]

Acute Radiation Syndrome: CNS—dose needed?

> 20-50 Gy [CNS: > 20-50 Gy, 4-6 hour latent period, death within 3 days.]

Acute Radiation Syndrome: CNS—latent period?

4-6 hours [CNS: > 20-50 Gy, 4-6 hour latent period, death within 3 days.]

Acute Radiation Syndrome: CNS—outcome?

Death within 3 days [CNS: > 20-50 Gy, 4-6 hour latent period, death within 3 days.]

Acute Radiation sickness: WB Dose: < 1 Gy - Effect on GI - Effect on skin - Action needed

GI: no vomiting Skin: no redness Action: surveillance for 5 weeks

Acute Radiation sickness: WB Dose: 1-2 Gy - Effect on GI - Effect on skin - Action needed

GI: vomiting 2-3 hours after exposure Skin: redness 12-24 hours after Action: surveillance for 3 weeks, consider general hospital

Acute Radiation sickness: WB Dose: 2-4 Gy - Effect on GI - Effect on skin - Action needed

GI: vomiting 1-2 hours after Skin: redness 8-15 hours after Action: hospitalize - burn center

Acute Radiation sickness: WB Dose: > 4 Gy - Effect on GI - Effect on skin - Action needed

GI: vomiting < 1 hour after Skin: redness 1-6 hours after Action: hospitalize - Specialized radiation center

Transient equilibrium: What is it? Classic example? How long until achieved? (In half lives)

Equilibrium that occurs when half life of the daughter is shorter than the parent (but not by a lot). Classic example: Moly-99 generator making Tc-99. A transient equilibrium happens after 4 half lives (usually).

Routine premedication: 2 methods - drugs - doses - routes - frequencies

``` Method 1: -prednisone, 50 mg, PO -13 hours, 7 hours, 1 hour (before contrast) -diphen (50 mg IV) 1 hour before (can PO) ``` ``` Method 2: -methylprednisolone, 32 mg, PO -12 hours, 2 hours (before contrast) -diphen (50 mg IV) 1 hour before (can PO) ``` [NOTE: diphen present and EXACTLY same for ALL premeds.]

Emergent Premedication: 3 methods: - drugs - doses - route - frequency

``` Method 1: -methylprednisolone, 40 mg, IV OR hydrocortisone sod. succ., 200 mg, IV -q4 until contrast -diphen (50 mg IV) 1 hour before ``` ``` Method 2: *If NSAID allergy or history asthma -dexamethasone sodium, 7.5 mg, IV OR Betamethasone, 6 mg, IV -Q4 until contrast -diphen (50 mg IV) 1 hour before ``` Method 3: * If can’t give steroids—infection, risk of bowel perforation - just diphen (50 mg IV) 1 hour before [NOTE: diphen is present and EXACTLY same for all!]

Exposure Dose Limits: Occupational workers: Minimal age?

18 years

Exposure Dose Limits: Occupational workers: Lens?

150 mSv/yr | “(Some new papers say 20 mSv)”

Exposure Dose Limits: Occupational workers: Radiation worker?

50 mSv /yr

Exposure Dose Limits: Occupational workers: Extremity?

500 mSv/yr

Exposure Dose Limits: Public Exposure: Infrequent?

5 mSv/yr

Exposure Dose Limits: Public Exposure: Continuous ?

1 mSv/yr

Exposure Dose Limits: Public Exposure: Embryo/fetus via MOTHER?

5 mSv/yr (1 mSv to fetus directly)

Exposure Dose Limits: Public Exposure: Embryo Fetus (post declared pregnancy)?

0.5 mSv/MONTH

Exposure Dose Limits: Public Exposure: Controlled areas?

50 mSv/yr

Exposure Dose Limits: Public Exposure: Uncontrolled areas?

5 mSv/yr

Exposure Dose Limits: Public Exposure: Genetically Significant Dose?

0.25 mSv

Exposure Dose Limits: Public Exposure: Effective dose from background radiation in US?

3 mSv/yr

Package labels: what does it mean?? WHITE 1 - special handling? - surface dose rate? - 1 meter dose rate?

no special handling Surface: < 0.5 mrem/hr 1 meter: 0 mrem/hr

Package labels: what does it mean?? YELLOW 2 - special handling? - surface dose rate? - 1 meter dose rate?

-special handling, yes Surface: < 50 mrem/hr 1 meter: < 1 mrem/hr

Package labels: what does it mean?? YELLOW 3 *bc the assholes couldn’t choose another color - special handling? - surface dose rate? - 1 meter dose rate?

Special handling, yes Surface: < 200 mrem/hr 1 meter: < 10 mrem/hr

MRI 2D Table Time formula

Time=TR x Phase Matrix x NEX TR: time between each RF pulse (usu in milliseconds) Phase Matrix: data the system collects from each phase encoding step NEX: number of times each set of phase encoding steps is repeated (Number of EXcitations)

MRI 3D Table Time Formula (Note: unless they specify 3D in question, you should assume it’s 2D).

Time=TR x Phase Matrix x NEX x # Slices!!! [slices # is what’s different from 2D!] TR: time between each RF pulse (usu in milliseconds) Phase Matrix: data the system collects from each phase encoding step NEX: number of times each set of phase encoding steps is repeated (Number of EXcitations)

MRI Better Spatial Resolution if: Small or Large VOXEL?

SMALL voxel

MRI Better Spatial Resolution if: Small or Large FIELD OF VIEW?

SMALL Field of view

MRI Better Spatial Resolution if: Smaller or Larger MATRIX?

LARGER matrix

MRI Better Spatial Resolution if: Thinner or Thicker SLICES?

THINNER slices

MRI Better Spatial Resolution if: “Steep (Large) Slice Selection Gradient, and Thin Transmit Bandwidth”

MRI Better SNR if: Weaker or Stronger magnet?

STRONGER magnet

MRI Better SNR if: Short or Long TR?

LONG TR

MRI Better SNR if: Small or Big FOV?

BIG FOV

MRI Better SNR if: Small or Large SLICES?

LARGE slices

MRI Better SNR if: Less or More NEX?

MORE NEX

MRI Better SNR if: Short or Long TE

SHORT TE

MRI Better SNR if: Small or Large Matrix?

SMALL Matrix

MRI Better SNR if: Small or Large Receiver Bandwidth?

SMALL Receiver Bandwidth

MRI Better SNR if: _______ COIL SIZE

Appropriate

MRI Better SNR if: “Shallow (small) slice selection gradient, and Thick transmit bandwidth”

MRI, Potential Fuckery: Terms that sound very similar! Fat *Receiver* Bandwidth = _____ SNR Fat *TRANSMIT* Bandwidth = _____ SNR (Small or Large slice?)

Fat *Receiver* Bandwidth =DECREASE SNR Fat TRANSMIT Bandwidth = Large slice= Increased SNR

MRI, Potential Fuckery: Terms that sound very similar! Narrow *Receiver* Bandwidth = _____ SNR Narrow *TRANSMIT* Bandwidth = _____ SNR (Small or Large slice?)

Narrow *Receiver* Bandwidth = INCREASED SNR Narrow TRANSMIT Bandwidth = Small/Thin slice = DECREASED SNR