Introduction to Radiotherapy

Question 1

A medical specialist certified in the
practice of radiation oncology in
the Philippine Board of Radiation
Oncology and is at least responsible for consultations, dose prescriptions, on-treatment supervision and evaluations,
treatment summary reports, follow-up monitoring and evaluation of treatment outcome
and morbidity.

Answer 1

Radiation Oncologists

Question 2

An individual who has PhD or
Masters Degree in Medical Physics
with the appropriate clinical
training in radiation oncology
medical physics.

Answer 2

Medical Physicist

Question 3

Performs Dosimetry works,
calibration, and design treatment
plans by means of computer or
manual computation of radiation
doses.

Answer 3

Medical Physicist

Question 4

performs Dosimetry works, calibration, and design treatment plans by means of computer or manual computation of radiation doses

Answer 4

Medical Physicist

Question 5

A _____ duly licensed by the PRC, who is
practicing radiotherapy technology
and is responsible for operating
simulators, computed tomography
(CT) scanners, treatment units etc;
for accurate patient set-up and
delivery of a planned course of
radiation therapy prescribed by a
radiation oncologist; and for
documentation of treatment.

Answer 5

radiologic technologist

Question 6

Radiation Therapy team

Answer 6

RADIATION ONCOLOGISTS
MEDICAL PHYSICIST
RADIOTHERAPY TECHNOLOGIST
ONCOLOGY NURSE

Question 7

is performed by a group of team members, including the radiation oncologist, radiation physicist,
radiotherapist, dosimetrist, nurse, psychologist, and/or social workers.

Answer 7

Radiotherapy

Question 8

The treatment success in radiotherapy is _____ on adequate technical equipment.

Answer 8

highly dependent

Question 9

the first step in radiotherapy

Answer 9

simulation

Question 10

is radiotherapy field determination using a diagnostic X-ray machine with similar physical and geometrical features to the actual teletherapy machine.

Answer 10

Simulation

Question 11

The simulation can be performed by ____, or rarely by ____

Answer 11

CT, MRI

PET–CT

Question 12

The simulation performed by a
_____ is a real- time simulation procedure, since it is done directly in the patient.

Question 13

the simulation performed
by a ____ is a virtual simulation
since the tumor is localized
digitally.

Question 14

BASIC STEPS OF RADIOTHERAPY PROCEDURE

Answer 14

Immobilization
Imaging
Tumor Localization
Treatment Planning
Set-up
Treatment
Quality Control

Question 15

desired SSD value is usually

Answer 15

80–100 cm

Question 16

Parameters that Should Be Written on the Simulation Film:

Answer 16

Simulation date
Field size
Gantry angle
Collimator angle
Depth
Magnification factor
Physician name
Technician name
SSD
SAD
Patient position
Right and left signs

Question 17

Reference points are determined
by _____ located at the cross-sections of the lasers

Answer 17

radiopaque markers

Question 18

three reference points for CT Simulation:

Answer 18

craniocaudal
right and left lateral sides

Question 19

The region of interest (that for
which serial CT slices are to be
taken) is determined by the

Answer 19

radiation oncologist

Question 20

The patient should then rest for ____ after CT to check for any possible adverse reactions.

Answer 20

20 min

Question 21

defined as visible tumor volume in images

Answer 21

GTV: gross tumor volume

Question 22

defined as GTV + subclinical/invisible invasion

Answer 22

CTV: clinical target volume

Question 23

defined as CTV + IM (internal margin for organ motion)

Answer 23

ITV: internal target volume

Question 24

defined as ITV + SM (setup margin for setup error)

Answer 24

PTV: planning target volume

Question 25

Conventional Simulation Steps

Answer 25

Immobilization Patient Positioning Imaging and tumor localization

Question 26

Various types of apparatus are used for immobilization. The most frequently used apparatus is the

Answer 26

thermoplastic mask

Question 27

are predetermined locations for each region of the body.

Answer 27

Reference points

Question 28

The ____ has published many reports that are used to determine treatment parameters and define target volumes so that radiotherapy can be accurately planned.

Answer 28

International Commission on Radiation Units and Measurements (ICRU)

Question 29

The International Commission on Radiation Units and Measurements (ICRU) has published many reports including

Answer 29

•ICRU 50 and 62 on photon ener- gies of external treatments •ICRU 71 on electron energies •ICRU 38 (1985), ICRU 58 (1958), and ICRU 72 (2004) on brachytherapy treatment •ICRU 78 on proton therapy in 2007

Question 30

The _____ reports define the target volumes and organs at risk.

Answer 30

ICRU 50 and 62

Question 31

• is the macroscopic volume of the tumor • defines the tumor volume determined by clinical exam and imaging modalities (visible, palpable).

Answer 31

gross tumor volume (GTV)

Question 32

Visible or palpable tumor volume, clinical volume

Answer 32

GTV

Question 33

The _____ encompasses the possible regions into which the microscopic disease may extend, or regions with a high risk of involvement based on clinical experience (invisible tumor).

Answer 33

clinical target volume (CTV)

Question 34

• Subclinical volume and clinical volume

Answer 34

clinical target volume (CTV)

Question 35

The ____ defines the volume formed when the CTV is extended due to physiological organ movements or technical reasons.

Answer 35

planning target volume (PTV)

Question 36

The ____ is the volume, including the reference isodose, that has the minimum probability of incurring complications.

Answer 36

treatment volume (TV)

Question 37

is the volume that receives a significant dose, based on normal tissue tolerance doses.

Answer 37

irradiated volume (IV)

Question 38

Volume Definitions According to ICRU 50

Answer 38

GTV CTV PTV TV IV

Question 39

Volume Definitions According to ICRU 62

Answer 39

•internal target volume (ITV) •planning organs at risk volume (PRV) •Internal margin (IM) •setup margin (SM) •organ at risk (OAR) •conformity index (CI)

Question 40

In addition to the volumes defined by the ICRU 50 report, two new volumes termed the ____ were added.

Answer 40

•internal target volume (ITV) •planning organs at risk volume (PRV)

Question 41

defines physiological organ movements.

Answer 41

internal margin (IM)

Question 42

defines movements relating to the treatment and technique, and daily changes in setup position.

Answer 42

setup margin (SM)

Question 43

is an organ that may remain in the treatment field, and can cause changes to treatment plans and doses (spinal cord, heart, lungs, kidney, eye, etc.).

Answer 43

OAR

Question 44

The _____ is the combined volume of the CTV and IM.

Answer 44

internal target volume (ITV)

Question 45

The ____ defines the volume of the OAR that may reside in the PTV during treatment.

Answer 45

planning organ at risk volume (PRV)

Question 46

The _____ is a point outside the rapid dose change region that determines the PTV; it is easy to define and is dose-definable physically.

Answer 46

ICRU reference point and dose

Question 47

Focalized blocks are made up of

Answer 47

lead or Cerrobend

Question 48

Cerrobend is a mixture of _____ that melts at ____ and has an HVL of ____

Answer 48

lead (26.7%), bismuth (50%), zinc (13.3%), and cadmium (10%) 70 °C 1.3 cm

Question 49

are selected for deeply seated tumors

Answer 49

High energies

Question 50

are selected for superficially located tumors

Answer 50

lower energies or electron beams

Question 51

Advantages of Cerrobend

Answer 51

low melting point high density ease of shaping low cost

Question 52

Factors of energy selection

Answer 52

Organs at risk Target volume Depth