(1)
University of Miami Sylvester Cancer Center, Miami, Florida, USA
In some institutions, dosimetrists are responsible for high-dose brachytherapy (HDR) planning followed by a physics check and signature. Dose delivery procedures for HDR, however, are always handled by certified medical physicists because special training is required.
There is no significant difference in dosimetry between low-dose rate (LDR) and HDR brachytherapy planning, but there are biological differences in terms of the dose delivery.
5.1 General Concepts on Brachytherapy (Questions)
Quiz-1 (Level 2)
1.
Which of the following statements are true about brachytherapy?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Sources may be left in place for a limited period of time to irradiate the tissues.
II.
Brachytherapy delivers fractionated doses of 120–400 cGy multiple times separated by many hours or days.
III.
Brachytherapy uses sealed sources of ionizing radiation placed within the patient.
IV.
Brachytherapy is an external beam radiation therapy.
2.
Methods used in brachytherapy are:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Interstitial
II.
Intracavitary
III.
Surface application
IV.
Intravascular
3.
A procedure where a radioactive source is implanted and then left for several days before being removed describes:
A.
HDR brachytherapy
B.
LDR brachytherapy
C.
Permanent brachytherapy
D.
Local brachytherapy
4.
Which of the following is/are the advantages of the remote afterloading technique in HDR brachytherapy?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Reducing unnecessary exposure to personnel.
II.
Plan in advance.
III.
Prepare needed apparatus in advance.
IV.
Facilitate optimal loading of an implant after the apparatus is inserted but before the radioactivity is actually loaded.
5.
Packing material (gauze, etc.) is commonly used along with intracavitary applicators like a vaginal cylinder. What is the function of the packing in these implants?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Keep the applicator sterilized in the body
II.
Hold the applicator firmly in position
III.
Avoidbody fluids in contact with the applicator
IV.
Pushe normal tissues away from the source, reducing the dose to healthy tissue
6.
Which of the following is the best approach to reduce personnel exposure during a brachytherapy treatment?
A.
Hot implant technique
B.
Using dummy wires while treatment
C.
Remote afterloading technique
D.
Manual afterloading technique
7.
In 2D brachytherapy planning, to aid dose calculations and precise localization of the sources, which of the following is/are correct?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
At least two radiographs are necessary.
II.
Orthogonal films are taken at right angles (90°).
III.
Magnification factors are carefully determined for each film.
IV.
Two posterior oblique films at 120° are required.
8.
Modern remote afterloading units consist of:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Lead-shielded storage area for radioactive source
II.
Several channels for source transport
III.
A remote loading and unloading system
IV.
A variety of applicators that are inserted into the patient
9.
Which of the following are examples of applicator types with which remote afterloading systems can be used?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Interstitial brachytherapy
II.
Skin applicators
III.
Gynecologic intracavitary brachytherapy applicator
IV.
Endobronchial catheters
10.
The film magnification factor used in brachytherapy is given by:
A.
SFD/SAD
B.
SFD × SAD
C.
0.693/HVL
D.
F = [(SSD2 + d m)/(SSD1 + d m) × (SSD1 + d)/(SSD2 + d)]2
11.
In 2D brachytherapy planning, three-dimensional reconstruction of the source geometry is usually accomplished by using:
A.
Isodose curves
B.
Tandem and ovoid method
C.
Manchester system
D.
Orthogonal imaging or the stereo-shift method
12.
When planning an HDR treatment using a remote afterloader unit, the desired isodose distributions can be obtained by:
A.
Programming dwell position and dwell time of the source
B.
Using MLC to control dwell position and time
C.
Using compensators to control source position
D.
Programming how far the source travels
13.
Disadvantages of remote afterloader units include:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Quality assurance requirements are significantly greater.
II.
The units are expensive and require a substantial capital expenditure.
III.
Additional costs must be considered for room shielding.
IV.
Increase exposure to medical personnel.
14.
Which of the following are advantages of remote afterloading units?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Provide the capability of optimizing dose distributions beyond what is possible with manual afterloading.
II.
Treatment techniques can be made more consistent and reproducible.
III.
HDR remote afterloading permits treatment on an outpatient basis.
IV.
HDR remote afterloading is suited for treating large patient populations.
15.
According to the ICRU, the dose rate criteria at the dose specification point(s) for an LDR brachytherapy treatment is:
A.
0.4–2 Gy/h
B.
2–12 Gy/h
C.
>12 Gy/h
D.
>1,200 cGy/h
16.
The advantage(s) of using HDR systems over LDR systems is/are:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Optimization of dose distribution
II.
Outpatient treatments
III.
Elimination of staff radiation exposure
IV.
Minimum QA
17.
Disadvantages of HDR systems include:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Uncertainty in biological effectiveness
II.
Potential for accidental high exposures and serious errors
III.
Increased staff commitment
IV.
Inpatient treatment
18.
What are the differences between LDR and HDR system?
A.
LDR uses multiple sources together with inactive spacers to achieve typical treatment dose rates of about 0.4–2 Gy/h. HDR uses a single source, with a typical activity of 10–20 Ci.
B.
LDR uses a single source with a typical activity of 0.4–2 Gy/h. HDR uses multiple sources together with inactive spacers to achieve typical treatment dose rates of about 10–20 Ci.
C.
LDR uses multiple sources together with inactive spacers to achieve typical treatment dose rates of about 0.4–12 Gy/h; HDR uses a single source with a typical activity of 0.4–2 Gy/h.
D.
LDR uses a single source with a typical activity of 0.4–12 cGy/h. HDR uses multiple sources together with inactive spacers to achieve typical treatment dose rates of about 0.4–2 cGy/h.
19.
Which of the following are essential components of remote afterloading system?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Safe to house the radioactive source
II.
A local or remote operating console
III.
A source control and drive mechanism
IV.
Source transfer guide tubes and treatment applicators
5.2 Radioactive Source Characteristics (Questions)
Quiz-1 (Level 2)
1.
Which of the following radioisotopes is most commonly used in remote afterloader units?
A.
137Cs
B.
60Co
C.
192Ir
D.
226Ra
2.
Which of the following particles emitted in the radium decay series is of importance for clinical use?
A.
Alpha particles
B.
Beta particles
C.
Electrons
D.
Gamma rays
3.
Match the following radionuclides with their corresponding half-life:
A. | 226Ra | I. | (30.0 years) |
B. | 222Rn | II. | (73.8 days) |
C. | 60Co | III. | (3.83 days) |
D. | 137Cs | IV. | (59.4 days) |
E. | 192Ir | V. | (1,600 years) |
F. | 198Au | VI. | (17 days) |
G. | 125I | VII. | (2.7 days) |
H. | 103Pd | VIII. | (5.26 years) |
E. | 90Sr | IX. | (14.0 days) |
F. | 90Y | X. | (64 h) |
G. | 32P | XI. | (28 years) |
4.
Match the following radionuclides with their corresponding exposure rate constant Γ (Rcm2/mg-h):
A. | 226Ra | I. | (13.07) |
B. | 222Rn | II. | (4.69) |
C. | 60Co | III. | (10.15) |
D. | 137Cs | IV. | (2.38) |
E. | 192Ir | V. | (1.48) |
F. | 198Au | VI. | (8.25) |
G. | 125I | VII. | (1.45) |
H. | 103Pd | VIII. | (3.28) |
5.
Match the following radionuclides with their corresponding effective photon energy (MeV):
A. | 226Ra | I. | (1.25) |
B. | 222Rn | II. | (0.42) |
C. | 60Co | III. | (0.37) |
D. | 137Cs | IV. | (0.83 avg) |
E. | 192Ir | V. | (0.02) |
F. | 198Au | VI. | (0.028) |
G. | 125I | VII. | (0.83 avg) |
H. | 103Pd | VIII. | (0.66) |
6.
Match the following radionuclides with their corresponding decay rate:
A. | 226Ra | I. | (4 % daily) |
B. | 222Rn | II. | (18 % daily) |
C. | 60Co | III. | (1 % yearly) |
D. | 137Cs | IV. | (2.3 % yearly) |
E. | 192Ir | V. | (1 % monthly) |
F. | 198Au | VI. | (25 % daily) |
G. | 125I | VII. | (1 % daily) |
H. | 103Pd | VIII. | (>1 % yearly) |
7.
What do 131I, 32P, 90Y, and 90Sr have in common?
A.
They all emit gamma rays.
B.
They all emit β−.
C.
They all emit β+.
D.
They all have a very long T 1/2.
8.
Radium-226 (226Ra) has been replaced by other radioactive nuclides because:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Any leakage from a 226Ra source can result in deposition of a high radiation dose in bone.
II.
226Ra high average gamma ray energy can result in high exposures to medical personnel.
III.
Radon gas leakage represents a significant hazard if source is broken.
IV.
226Ra has a very short T 1/2 which makes the radionuclide impractical for brachytherapy treatments.
9.
Which of the following statements are true about 226Ra?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
226Ra is a decay product of 238U and decays to stable form of lead, 206Pb.
II.
Radium T 1/2 is 1,622 years.
III.
226Ra emits alpha particles, beta particles, and gamma rays.
IV.
226Ra sources are manufactured as needles or tubes in a variety of lengths and activities.
10.
What is the active length of a radium source?
A.
The distance between the actual ends of the source
B.
Milligrams of radium content
C.
The distance between the ends of the radioactive material
D.
Transverse thickness of the capsule wall, usually expressed in terms of millimeters of platinum
11.
How does one obtain the uniformity of activity distribution of a radioactive source?
A.
Taking orthogonal images (90°) apart of the source in the simulation room
B.
Placing the source on an unexposed x-ray film for a time long enough to obtain reasonable darkening of the film
C.
Doing a leak test to determine how much uniform activity the source has
D.
Using a well-type ion chamber
12.
Historically, what was characteristic of an Indian club radium needle?
A.
The amount of radium activity was uniformly spread throughout the active length.
B.
The amount of radium activity was uniform, but with higher activity at one end of the needle.
C.
The amount of radium activity was uniform, but with higher activity at both ends of the needle.
D.
Are usually furnished in multiples of 5 mg of radium filtered by 1 mm platinum.
13.
Which is the exposure rate constant of radium (226Ra)?
A.
3.27 R-cm2/mg-h
B.
8.25 R-cm2/mg-h
C.
13.07 R-cm2/mg-h
D.
8.25 R-cm2/mg-h
14.
The activity of radioactive nuclide-emitting photons is related to the exposure rate by:
A.
The exposure rate constant (Γ)
B.
The source construction
C.
The physical length of the source
D.
The half-life (T 1/2)
15.
The exposure rate constant of radium (226Ra) is measured:
A.
At a distance of 1 cm from a 1 mCi point source filtered by 0.5 mm platinum
B.
At a distance of 1 cm from a 1 mg point source filtered by 0.5 mm platinum
C.
At a distance of 1 mm from a 1 mCi point source filtered by 0.5 mm platinum
D.
At a distance of 1 cm from a 1 mg point source filtered by 0.5 mm lead
16.
Brachytherapy treatment sources are chosen based on:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
The half-life (T 1/2) of the source
II.
The photon energy (MeV) of the source
III.
The activity of the source
IV.
The half-value layer of the source
17.
Advantages of cesium-137 (137Cs) over radium include:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
137Cs requires less shielding than radium (226Ra).
II.
137Cs has a longer T 1/2 than radium (226Ra).
III.
137Cs is less hazardous in the microsphere form than radium (226Ra).
IV.
137Cs can be used clinically for 1,000 years without replacement.
18.
Match the following radionuclides with their form used. Answers can be used more than once:
A. | 226Ra | I. | Wire |
B. | 103Pd | II. | Needles |
C. | 60Co | III. | Powder |
D. | 137Cs | IV. | Seeds |
E. | 192Ir | V. | Grains |
F. | 198Au | VI. | Tubes |
G. | 125I |
19.
Which of the following radionuclides emit gamma (γ) rays for radiotherapy?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Radium-226 (226Ra)
II.
Cobalt-60 (60Co)
III.
Cesium-137 (137Cs)
IV.
Gold-198 (198Au)
20.
The main advantage of cobalt-60 (60Co) is:
A.
It is an inexpensive source.
B.
It has a very long T 1/2.
C.
60Co inventory system is simple.
D.
It has a high specific activity.
21.
60Co can be used to replace which of the following sources on an intracavitary application?
A.
Radium-226 (226Ra)
B.
Gold-198 (198Au)
C.
Iodine-125 (125I)
D.
Palladium-103 (103Pd)
22.
Which of the following statements are true about iridium-192 (192Ir)?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
192Ir is composed of 30 % alloy Ir and 70 % Pt.
II.
Because of the low energy, these sources require less shielding for personnel protection.
III.
The half-life is relatively short requiring frequent source replacement.
IV.
The source can be used in nonpermanent implants similar to radium and cesium.
23.
Gold-198 is used for:
A.
Intracavitary implant
B.
Surface molds implants
C.
Temporal implant
D.
Permanent implant
24.
Which are the advantages of iodine-125 (125I) when used for permanent implants over radon and gold-198 (198Au)?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Its encapsulation in titanium
II.
Its longer half-life (T 1/2)
III.
Its simple dosimetry
IV.
Its low photon energy
25.
The anisotropic dose distribution around iodine-125 (125I) sources creates:
A.
Hot spots near the source ends
B.
Cold spots near the source ends
C.
A change on its exposure rate constant
D.
Cold spots at the center of the source
26.
The advantage of palladium-103 (103Pd) over iodine-125 (125I) for permanent implants is:
A.
There are not any advantages; both are the same.
B.
103Pd is not encapsulated.
C.
103Pd can deliver a much faster dose rate.
D.
103Pd photon fluence distribution around the source is not anisotropic.
27.
The source strength for any radionuclide may be specified in terms of:
A.
Millicurie (mCi)
B.
Kilovoltage potential (kVp)
C.
Sievert (Sv)
D.
rem
28.
The exposure rate of a radionuclide at any particular point is:
A.
Proportional to the product of its mass and its exposure rate constant
B.
Proportional to the product of its activity and its exposure rate constant
C.
Proportional to its milligram of radium equivalent
D.
Proportional to the air kerma strength
29.
The National Council on Radiation Protection and Measurements (NCRP) recommends that the strength of any γ-emitter should be specified directly in terms of:
A.
Exposure rate in air at a specified distance such as 1 m
B.
Exposure rate in tissue at a specified distance such as 1 m
C.
Exposure rate in tissue at Dmax
D.
Exposure rate in air at Dmax
30.
Historically, brachytherapy sources are specified in terms of the equivalent mass of radium because:
A.
It is an accurate measurement.
B.
This is the only method used for source specification.
C.
Some users accustomed to radium sources continue to use mg-Ra eq.
D.
The best way to specify brachytherapy sources is in terms of mg-Ra eq.
31.
Apparent activity is defined as:
A.
The product of air kerma rate in free space and the square of the distance of the calibration point from the source center along the perpendicular bisector
B.
The activity of a bare point source of the same nuclide that produces the same exposure rate at 1 m as the source to be specified
C.
The thickness of material necessary to reduce the number of photons in a beam or intensity to 50 % of its initial value
D.
The activity of a source that produces different exposure rate at 1 m as the source to be specified
32.
1 mg-Ra eq is equal to:
A.
8.25 × 10−4 mR/h at 1 m
B.
8.25 × 10−4 R/h at 1 m
C.
8.25 × 10−2 R/h at 1 m
D.
8.25 × 10 R/h at 1 m
33.
The rapid falloff of radium-226 (226Ra), cobalt-60 (Co60), and cesium-137 (137Cs) at a distance of about 5 cm in tissue is due to:
A.
Inverse square law
B.
Tissue attenuation
C.
Double encapsulation of the isotopes
D.
Apparent activity
34.
A dosimeter used to calibrate brachytherapy source is:
A.
Thimble ionization chamber
B.
Extrapolation chamber
C.
Parallel-plate chamber
D.
Well-type ion chamber
35.
The dose rate constant of a radionuclide depends on:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
The type of source
II.
Its construction
III.
Its encapsulation
IV.
Its physical length
36.
Which of the following is true about radium sources?
A.
Because the half-life for radioactive decay is much longer for radium-226 than for any of its daughter products, radium achieves secular equilibrium with its daughters.
B.
Because the half-life for radioactive decay is not much longer for radium-226 than for any of its daughter products, radium achieves transient equilibrium with its daughters.
C.
Because the half-life for radioactive decay is much longer for radium-226 than for any of its daughter products, radium achieves transient equilibrium with its daughters.
D.
Because the half-life for radioactive decay is not much longer for radium-226 than for any of its daughter products, radium achieves secular equilibrium with its daughters.
37.
According to the AAPM and ICRU, the strength of a brachytherapy source must be specified in terms of:
A.
Air kerma rate K air(d ref)
B.
Activity
C.
Number of disintegrations per unit time
D.
Exposure rate produced at a given distance from the source
38.
Air kerma strength is defined as:
A.
The sum of the products of the reference air kerma rate and the duration of the application of each source.
B.
The product of air kerma rate in “free space” and the square of the distance of the calibration point from the source center along the perpendicular bisector
C.
The activity of a bare point source of the same nuclide that produces the same exposure rate at 1 m as the source to be specified
D.
Kinetic energy released in matter, measured in gray or rad
39.
The SI unit of the reference air kerma rate is:
A.
Gy/s
B.
cGy/Ci
C.
Curie (Ci)
D.
Becquerel (Bq)
40.
Brachytherapy source encapsulation:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Contains the radioactivity
II.
Provides source rigidity
III.
Absorbs any (α) alpha and, for photon-emitting sources, (β) beta radiation produced through the source decay
IV.
Allows for handling of the source without any complications.
41.
The useful radiation fluence from a brachytherapy source generally consists of:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Gamma (γ) rays
II.
Characteristic x-rays
III.
Bremsstrahlung radiation
IV.
Alpha (α) rays
42.
The choice of an appropriate photon-emitting radionuclide for a specific brachytherapy treatment depends on:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Photon energies and penetration
II.
Half-life and half-value layer (HVL)
III.
Specific activity and source strength
IV.
Encapsulation
43.
Some brachytherapy sources are doubly encapsulated in order to provide adequate shielding against:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Beta (β) particles
II.
Alpha (α) particles
III.
Leakage of radioactive material
IV.
Gamma (γ) rays
44.
Some of the radioactive isotopes used in liquid form include:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
131I
II.
32P
III.
198Au
IV.
90Y
5.3 Implant Methods (Questions)
Quiz-1 (Level 2)
1.
The Paterson-Parker or Manchester system of implant dosimetry:
A.
Uses uniform strength sources implanted in parallel lines or in an array
B.
Uses uniform strength sources to achieve a nonuniform dose distribution, higher in the central region of treatment
C.
Uses nonuniform strength sources to archive uniform dose distribution (within ±10 %) to a plane or volume
D.
Uses uniform strength sources spaced 1 cm apart
2.
Some methods used to provide optimal brachytherapy dose distributions in the irradiated volume are:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
The Paterson-Parker system
II.
The Memorial system
III.
The Paris system
IV.
The MLC system
3.
The implant types used in the Manchester system are:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Planar implant
II.
Circular implant
III.
Volume implant
IV.
Triangular implant
4.
In the case of planar implants for the Paterson-Parker or Manchester system:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
The prescribed dose is 10 % higher than the minimum dose.
II.
The prescribed dose is 10 % lower than the minimum dose.
III.
The maximum dose should not exceed 110 % of the prescribed dose.
IV.
The maximum dose should exceed 110 % of the prescribed dose.
5.
In the case of planar implants with the Paterson-Parker or Manchester system, if the size of the implant is 50 cm2, what fraction of radium is used in the periphery and what fraction is used in the center?
A.
1/3 in the center, 2/3 in the periphery.
B.
2/3 in the center, 1/3 in the periphery.
C.
The distribution is even throughout the area.
D.
½ in the center, ½ in the periphery.
6.
Which of the following statements are true about planar implants with the Paterson-Parker or Manchester system?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
The spacing of the needles should not exceed 1 cm from each other or from the crossing ends.
II.
If the ends cannot be crossed, reduce the activity by 10 % from the area for each uncrossed end.
III.
One needle should touch the end of the next around the periphery, while in the central area, they should be spread out uniformly.
IV.
The needles should lie parallel to each other within the plane.
7.
If it is impossible to cross both ends on a single-plane Paterson-Parker or Manchester system implant, then:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
The treatment area should be considered as 90 % of the length of the implant.
II.
The treatment area should be considered as 80 % of the length of the implant.
III.
Use of Indian club needles eliminates the need for crossing needles at both ends.
IV.
Use of dumbbell needles eliminates the need for crossing needles at both ends.
8.
A volume implant is required if the lesion is:
A.
Less than 2.5 cm thick.
B.
More than 2.5 cm thick.
C.
Less than 2 cm thick.
D.
It could be perform at any lesion thickness.
9.
Which of the following are types of volume implants used in the Paterson-Parker or Manchester system?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Cylinder volume shape
II.
Sphere volume shape
III.
Cuboid volume shape
IV.
Octagon volume shape
10.
Which of the following statements are true about the distribution of sources in a volume implant using the Paterson-Parker or Manchester system?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
The amount of radium is divided into eight parts for all the volume types.
II.
The cylinder is composed of a belt (four parts), a core (two parts), and each end (one part).
III.
The sphere is made up of a shell (six parts) and a core (two parts).
IV.
The cuboid consists of each side (one part), each end (one part), and a core (two parts).
11.
Which of the following statements are true about volume implants used in Paterson-Parker or Manchester system?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
The needles should be spaced as uniformly as possible, not more than 1 cm apart.
II.
The prescribed dose is stated 10 % higher than the minimum dose within the implanted volume.
III.
There should be at least eight needles in the belt and four in the core.
IV.
If the ends of the volume implant are uncrossed, 7.5 % is deducted from the volume for uncrossed end.
12.
In the case of an implant using the Quimby system:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
For the planar implant, the stated dose is the maximum dose in the plane of treatment.
II.
For the planar implant, the stated dose is the minimum dose in the plane of treatment.
III.
For the volume implant, the stated dose is the minimum dose within the implant volume.
IV.
For the volume implant, the stated dose is the maximum dose within the implant volume.
13.
Which of the following is an extension of the Quimby system?
A.
The Paris system
B.
The Paterson-Parker system
C.
The Memorial system
D.
The Manchester system
14.
The Paris system:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Uses sources of uniform linear activity.
II.
The line source spacing must be constant, but the space is selected according to implant dimensions.
III.
Uses sources implanted in parallel lines.
IV.
Crossing needles are not used.
15.
What is the minimum and maximum source separation according to implant dimensions allowed using the Paris system?
A.
Minimum of 1 cm, maximum of 2 cm
B.
Minimum of 8 mm, maximum of 2 cm
C.
Minimum of 8 mm, maximum of 1.5 cm
D.
Minimum of 1 cm, maximum of 15 mm
16.
The reference isodose in the Paris system is fixed at:
A.
85 % of the basal dose
B.
50 % of the basal dose
C.
95 % of the prescribed dose
D.
95 % of the volume to receive 100 % of the dose
17.
The basal dose is defined as:
A.
The average of the maximum dose between sources
B.
The average of the minimum dose between sources
C.
The maximum dose in the plane of treatment
D.
The total dose contribution from each point
18.
Mach the following types of brachytherapy implants with its corresponding description.
A.
Intracavitary
B.
Interstitial
C.
Surface (mold)
D.
Intraluminal
E.
Intraoperative
F.
Intravascular
G.
Temporal
H.
Permanent
I.
Dose is delivered over the lifetime of the source until completely decayed.
II.
A single source is placed into small or large arteries.
III.
Sources are placed into body cavities close to the tumor volume.
IV.
Dose is delivered over a short period of time, and the sources are removed after the prescribed dose has been reached.
V.
Sources are placed over the tissue to be treated.
VI.
Sources are implanted surgically within the tumor volume.
VII.
Sources are implanted into the target tissue during surgery.
VIII.
Sources are placed in a lumen.
19.
The brachytherapy hot loading method is defined as:
A.
The applicator is placed first into the target position and the radioactive sources are loaded later, either by hand or by a machine.
B.
The applicator is preloaded and contains radioactive sources at the time of placement into the patient.
C.
The applicator is hot, so it cannot be inserted directly into the patient.
D.
The applicator contains hot sources, so it cannot be inserted directly into the patient.
20.
Match the following applicators with its corresponding definition.
A.
Fletcher-Suit
B.
Vaginal cylinder
C.
Rectal applicator
D.
Intraluminal catheter
E.
Nasopharyngeal applicator
F.
Interstitial implant
I.
Used for treatments of prostate gland, gyn malignancies, breast, and some head and neck tumors. Hollow needles are implanted into the tumor, and the source is introduced into the needle.
II.
Used for treatment of endobronchial carcinoma. Suitable diameter catheters of various lengths.
III.
Used for treatment of nasopharyngeal tumors with HDR. The applicator set includes tracheal tube, catheter, and a nasopharyngeal connector.
IV.
Used for treatment of gynecological malignancies of the uterus, cervix, and pelvic side walls. Consists of rigid intrauterine tandems with curvatures of 15°, 30°, and 45° and a pair of ovoids.
V.
Used for treatment of vaginal wall. Consists of acrylic cylinders having a variety of diameters and an axially drilled hole to accommodate a catheter.
VI.
Used for treatment of superficial tumors of the rectum. Consists of acrylic cylinders of different diameters. Selected shielding is incorporated to spare normal tissue.
5.4 Temporary Implant Procedures (Questions)
Tandem and ovoids (LDR, HDR), vaginal cylinder (HDR), and eye plaque (LDR)
Quiz-1 (Level 2)
1.
Which of the following are considered surface applicators?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Sr-90 applicator
II.
COMS eye plaque
III.
Molds applicator
IV.
Tandem and ovoid
2.
A Sr-90 applicator is used to treat:
A.
Choroidal melanoma
B.
Pterygium
C.
Ocular melanoma
D.
Skin lesions
3.
Sr-90 is a:
A.
Gamma (γ) emitter
B.
Alpha emitter
C.
Beta-minus emitter
D.
Neutron emitter
4.
The sources typically used for COMS eye plaques are:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Radium-226 (226Ra)
II.
Iodine-125 (125I)
III.
Gold-198 (198Au)
IV.
Palladium-103 (103Pd)
5.
For a volume implant using the Manchester system, the radioactive material is distributed on the belt, the core, and the ends. Which part of the implant is the belt?
A.
The inner needles
B.
The crossing needles
C.
The periphery
D.
The uncrossing end
6.
What does the acronym COMS stand for?
A.
Cornea obstruction melanoma study
B.
Choroidal ocular melanoma study
C.
Concave obstructive melanoma study
D.
Custom ocular mold study
7.
The two major parts of a COMS eye plaque are:
A.
Gold backing and Silastic seed insert
B.
Tungsten backing and Silastic seed insert
C.
Lead backing and silicone
D.
Wax backing and plaster of Paris
8.
Surface molds can be used to treat:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Superficial skin lesions
II.
Lesions of the oral and nasal cavity
III.
Lesions of the hard palate
IV.
Lesions to the prostate
9.
In interstitial therapy, the radioactive sources are fabricated in the form of:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Needles
II.
Wires
III.
Seeds
IV.
Grains
10.
Which of the following sources are used in a temporal interstitial implant?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Radium needles
II.
Gold (198Au) seeds
III.
Iridium wires or seeds
IV.
Iodine-125 (125I) seeds
11.
Intracavitary therapy is mostly used for cancers of the:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Vagina
II.
Cervix
III.
Uterine body
IV.
Bladder
12.
The most common method of intracavitary brachytherapy is:
A.
COMS eye plaque applicator
B.
Needles using the Paris system
C.
Fletcher tandem and ovoid applicator
D.
Henschke applicator
13.
Which of the following systems of dose specification for cervix treatment is the most extensively used?
A.
Milligram-Hours
B.
The Manchester system
C.
The International Commission on Radiation Units and Measurements System
D.
The Quimby system
14.
The Milligram-Hours system is not used because:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
It lacks information on source arrangement.
II.
It lacks information for the position of the tandem relative to the ovoids.
III.
It lacks information of packing for the applicators.
IV.
It lacks information of tumor size and patient anatomy.
15.
The Manchester system used for treatment of the cervix is characterized by dose to?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Point A and B
II.
Rectum point
III.
Bladder point
IV.
Bowel point
16.
The duration of the implant for a brachytherapy treatment of the cervix using the Manchester system is based on:
A.
Dose rate calculated at point B
B.
Dose rate calculated at the bladder point
C.
Dose rate calculated at the rectum point
D.
Dose rate calculated at point A
17.
The point of prescription for a brachytherapy treatment of the cervix using the Manchester system is:
A.
Point A
B.
Point B
C.
Bladder point
D.
Rectum point
18.
On a brachytherapy treatment of the cervix, point A is defined as:
A.
2 cm superior to the lateral vaginal fornix and 2 cm lateral to the cervical canal
B.
2 cm superior to the external cervical os and 2 cm lateral to the cervical canal
C.
2 cm superior to the internal cervical os and 2 cm lateral to the cervical canal
D.
2 cm inferior to the lateral vaginal fornix and 2 cm lateral to the cervical canal
19.
On a brachytherapy treatment of the cervix, point B is defined as:
A.
2 cm superior to the external cervical os or head of the ovoids and 5 cm lateral to point A if the uterus is tipped
B.
3 cm superior to the external cervical os or head of the ovoids and 2 cm lateral to point A if the uterus is not tipped
C.
2 cm superior to the external cervical os or head of the ovoids and 3 cm lateral to point A if the uterus is not tipped
D.
5 cm superior to the external cervical os or head of the ovoids and 4 cm lateral to point A if the uterus is tipped
20.
On a brachytherapy treatment of the cervix, point A represents:
A.
The location where the uterine vessels cross the ureter
B.
The location of the obturator nodes
C.
The location of the bladder
D.
The location of the rectum
21.
Limitations to using point A as a prescription point on a brachytherapy treatment of the cervix include:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
It relates to the position of the sources and not to a specific anatomic structure.
II.
Dose to point A is very sensitive to the position of the ovoid sources relative to the tandem sources.
III.
Depending on the size of the cervix, it may lie inside the tumor or outside.
IV.
Dose prescription at point A could risk underdosage of large cervical cancers or overdosage of small ones.
22.
Recently, for an intracavitary treatment, the ICRU has recommended a system of dose specification that relates the dose distribution to:
A.
Point A
B.
Point B
C.
Target volume
D.
Bladder and rectum points
23.
Get Clinical Tree app for offline access
Tandem and ovoid applicators are used for:
A.
Cervical cancer patients after a hysterectomy has been performed
B.
Cervical cancer patients when no hysterectomy has been performed
C.
Any patient who has cervical cancer
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