[1] What are
the differences (disadvantages and advantages) between LINACS and Cobalt-60
machines e.g. doserate?
[2] Sketch the
main components of a linear accelerator.
[3] Describe the theory of beam production and the part each component plays in the production of a clincally useful beam:
·
Modulator
·
Klystrons & Magnetron
·
Electron Gun
·
Accelerator Waveguide
·
Bending Magnet
·
Target
·
Flattening Filter
·
Collimation (primary & secondary)
·
Monitor Ionisation Chambers
·
Wedges (physical/flying/dynamic)
[4] What
changes are made to change the Linac from photon to electron mode?
[5] What are
the differences between the Varian 600C and the Siemens KD2?
Orthovoltage (Conventional) X-ray
Machines
[6] Describe
the operation of a standard therapy x-ray machine.
[7] What is
the purpose of the beryllium window (how thick)?
[8] How is
most of the energy lost?
[9] Describe
how and why full wave rectification of the high voltage supply is necessary.
[10] Sketch the
radiation spectrum seen, with and without the effect of target filtration and
additional filtration.
[11] Explain
the need for external filters.
[12] What
materials are used?
[13] Why do
applicators for x-rays (>150kVp) have a closed perspex end?
[14] What is
the ‘Heel Effect’?
[15] Sketch
depth dose curves for 300, 100 and 50kV x-rays.
[16] What are
the approximate 90% depths for low and medium energies?
Ionisation Chambers
[17] Sketch a
free air ionisation chamber set-up.
[18] What is
the definition of exposure?
[19] How does
this affect the design of the free-air ionisation chamber?
[20] What
thickness of surrounding air is required at 200kV? 300kV?
[21] Sketch a
simple thimble chamber.
[22] What is
the air equivalent wall?
[23] What is
the calibration chain for ionisation chambers at your training hospital?
[24] Describe
the consistency checks using Strontium-90.
Photon/Electron Interactions &
Depth Dose Characteristics
[25] Describe
the main photon interaction processes, their energy and atomic number
dependence and threshold for domination using a graph.
[26] Describe
the main electron interaction processes.
[27] Sketch
depth dose curves and isodose distributions for kilovoltage, megavoltage and
electron beams.
[28] What is
the ‘rule of thumb’ describing the relationship between dMAX and the
photon/electron energy?
[29] What are
the advantages in terms of treatment planning of each of these types of
radiation?
Exposure, Absorbed Dose and Air
Kerma
[30] Give the
definitions and units of each of the above quantities.
[31] How are
the three related?
[32] What
calculations must be made to change dose in air to dose in water?
[33] Sketch
graphs indicating the differences at increasing energy for bone and tissue.
[34] Under what
conditions can air kerma and dose be considered identical, when not?
Brachytherapy: Intracavity
[35] What is
intracavity brachytherapy?
[36] What are
the advantages of this type of treatment?
[37] Describe the properties of an ideal source and relate to currently used Cs-137 & Ra-226.
[38] What are
the advantages of afterloading brachytherapy devices?
[39] What are
the approximate dose rates for LDR, MDR & HDR afterloading systems?
[40] What are
biological effects of using a LDR or MDR machine?
[41] Describe
the Selectron suite and afterloading machine (plus applicators) at your
training hospital.
[42] What
radiation protection devices are in place?
[43] What is
the purpose of catheterisation?
[44] What are
the anatomical origins and geometrical positions of points A & B in the
Manchester system?
[45] What are
the dose limits to the rectal and bladder points?
Brachytherapy: Interstitial
[46] What are
the major features of the Paris system of dosimetry (9 Rules)?
[47] How does
this differ from the Manchester system?
[48] What are
the properties of Ir-192?
[49] In dose
calculations what are the basal doserate, the reference doserate and the
treatment volume.
[50] What is
the effective length of the hairpin taken to be?
Unsealed Source Therapy
[51] What are
the properties of I-131?
[52] How is it
used therapeutically?
[53] What are
the administered activities for ablation and overactive thyroid treatment?
[54] Describe
the procedure in each case.
QA Procedures (Megavoltage)
[55] List the
daily checks performed and the tolerances for each result.
[56] What
additional checks are performed weekly?
[57] List the
checks performed monthly on the Linac (8).
[58] What codes
of practice are used?
[59] Describe
the experimental set-up including the field size, MU, build-up material,
tolerances, etc. for each check.
[60] What is
the definition of TMR?
QA Procedures (Kilovoltage)
[61] What is
the code of practice relating to kilovoltage output measurements?
[62] How has
this changed since the previous document?
[63] How are
the three energy ranges categorised?
[64] Describe
the procedure for checking the output reading.
[65] What is
the backscatter factor?
[66] What
corrections must be applied to the instrument reading? After multiplication by
chamber calibration factor, mass absorption coefficient, ratio water/air, etc.
[67] What are
the differences between the measurement/calculation made for outputs at 90, 135
and 300kV?
[68] What other
QC procedures might be carried out on the kilovoltage unit (5)?
[69] Describe
the calibration chain for ionisation chambers & dosemeters.
[70] Describe
the procedure for consistency checks with Sr-90.
[71] Briefly
describe QC checks performed on the Selectron.