Dosimetry: Final Exam

Name that fractionation:
Irradiating a patient twice daily with a smaller than normal daily dose, making it possible to deliver 15-20% more dose over the same period of time.

Name that fractionation:
Delivering the same dose over a shorter period of time.

When did Wilhelm Conrad Roentgen discover x-rays?

Who discovered radioactivity?

What are the 3 most important factors in radiation protection?
describe the relationship of each to reduction in exposure

What is the half-life of Cobalt-60

The gross palpable extent and location of malignant growth:

The tissue volume that contains the GTV and subclinical microscopic malignant disease:

Contains the tumor and adjacent tissues:

To calculate the energy needed to treat along 90% isodose line for electrons multiply the depth by ______.

To calculate the energy needed to treat along 80% isodose line for electrons multiply the depth by ______.

What is the formula used to calculate the MU for electrons?

What is the formula used to calculate the wedge angle?

Rule of Thumb:

When in doubt when calculating energy to for an electron treatment the energy (MeV) should be ____ the maximum depth of the tumor.

The energy of a photon beam divided by four will give you the depth of the beam's _______ in most cases.

What does the RT (T) stand for?

The purpose of this machine is to duplicate the geometry & mechanical movements of radiation therapy machine, what is it?

What is the ratio of the absorbed dose at a given depth to the absorbed dose at a fixed reference point, usually D_max ?

What is the ratio of the absorbed dose at a given depth in tissue to the dose at the same point when it is at D_max ?

The region near the edge of the field margin where the dose falls rapidly:

The angle through which an isodose curve is tilted at the central axis of the beam at a specified depth.

What is the ratio of the dose rate of a given field size to the dose rate of the reference field size?

A sheet of Lucite placed in the beam to reduce it's depth of D_max is called a ___________.

The dose delivered to a patient is dependent upon these six factors:

Radiation therapy units operating at approx 50-120 kVp are:

Orthovoltage units usually operate at ______ SSD.

Orthovoltage units usually operate in the energy range of :

LINACs produce high energy beams by accelerating CHARGED particles in a ___________

A collimator _____ the beam.

The photon beam from a LINAC is intercepted by:

A flattening filter reduces the __________ in the center of the unfiltered beam

The average energy of a Cobalt 60 beam is:

The half-life of Cobalt 60 is:

Dose rates ________ with increased field size & ________ with increased distance.

The TAR at 5 cm depth for a 10x10 field minus the TAR at 5 cm depth for a 0x0 field gives the:

In a fixed SSD technique, the dose is usually normalized (or weighted) at ________. 

In an isocentric technique, the dose is usually normalized (or weighted) at _________.

In an electron beam, the _____ isodose curve bulges and the _____ isodose curve constricts.

When parallel opposed 6 mV photon beams are used in a 20 cm thick patient, the maximum dose will occur at:

To minimize the risk of hot or cold spots in the junction between photon fields, the gap should be:

The three planes in a patient are across the body, along the body in a lateral view & along the body in an anterior view. Respectfully, these are referred to as:

☆The Abdomen is defined as the portion of the body that lies between the _______ & the ________ and that contains the __________.

☆Generally speaking, the kidney tolerance dose to irradiation in the adult is:

☆The most common site of pancreatic tumors is the ______ of the pancreas.

☆Wilms' tumor is a tumor originating in the _______.

☆Neuroblastoma is a tumor most often originating in the __________.

☆When pelvic irradiation is delivered in an obese patient in the supine position, the concern is that uncertainty of dose due to variations in patient _________ would be caused when attempts were made to eliminate skin folds.

☆To reduce the volume of __________ within a pelvic field, the patient's position should be prone on a belly board.

☆The primary purpose of a testicular shield is to reduce the amount of _________ dose in the testes.

☆Of gynecological tumors treated with radiation therapy, the most common type is:

☆The depth of the deep inguinal nodes can vary from _____ to _____cm depending on the patient's size.

The dose under a 5-HVT kidney block is approximately ______ to ______% of the dose delivered at mid-depth on the central axis.

When a three field technique (anterior and lateral opposed fields) is used in the treatment of pancreatic tumors, the best dose distribution is achieved with wedge(s) in the ________ field(s) and more weighting on the ________ field(s).

How much of the kidney should be excluded from the treatment field in order to preserve proper function?

When patients with advanced cervical carcinoma are treated, the majority is delivered via ________.

Insertion of a 1-HVT block in both fields during the entire course of treatment would deliver approx ______ of the dose in the shielded organs and the dose distribution under the shields would be similar to that of using ______ shields only during a portion of the treatment.

What are the three methods of kidney blocking?

☆The 10-year survival for patients with all stages of Hodgkin's disease is approximately:

☆The patient position for treatment of a mantle field in Hodgkin's disease is usually supine with the ________ extended and the arms __________.

☆It is always important to align the patient with the ________ laser every day because if it is not, the field is rotated with respect to the patient's body.

☆Tattoos made in the patient's skin indicating irradiated areas can shift due to _______ and ________.

☆The advantages of ________ therapy are that it provides superior normal-tissue sparing and improved precision.

☆High- and low- dose total body irradiation is used in the preparation for a _________ and in the treatment of ____________.

☆The most common position for patients receiving total-skin electron irradiation is ___________.

☆The main goal of radiation therapy in patients with bone metastasis is to prevent ________ and reduce _________.

☆In patients treated for a spinal cord compression, the treatment field should include approximately two ____________ in each direction beyond demonstrable disease.

What is the average depth of the spinal cord?

The average dose and fractionation schedule for multifocal brain metastasis treatment is _____ cGy in ____ week
or
_____ cGy in ____ weeks

A typical treatment regimen of the cervix would include:

DICOM (Digital Imaging and Communications in Medicine)  is an established standard format for the use and exchange of medical ________, media and ________ across a computer network. (a LAN or a WAN)

Where is Point A located?

An off axis point is any point not on the ____________. The off axis point is used as a __________ point to tell the Dr what the dosage and effect on the tissue at that point will be as well as to find the __________.

The iliac crest is at the level of ______ in the spine.

A _______________ is a computer generated 2D radiograph displaying skeletal anatomy rendered from a three dimensional data set, such as CT or MRI.

What is the most common intracranial tumor?

The attenuation of Cerrobend is about _______ less than lead.

What is make-up of Cerrobend?

(percentage of each material)

Secondary scatter in the metal-tissue interface can cause high dose in the adjacent tissues but can be reduced by placing ___________ over the teeth.

When a lip lesion is treated, it is possible to reduce the mucosal reaction by placing an internal shield _______ to the tumor and covering the shield with ________.

If a 30° wedge is left out of the treatment during two of five treatments, the central axis dose is ________ (increased/decreased) and the isodose distribution ______ (is/is not)  affected.

Treatment fields should be labeled in the chart with reference to:
(2)

The most commonly used beam energy to treat head & neck cancer is:

The majority of cancer in the head & neck region is:

Xerostomia is caused by irradiation of the

In the treatment of head & neck cancer, immobilization is particularly important because of:
(2)

Retinoblastoma is a tumor of the eye that usually occurs in:
(what age group?)

Parotid tumors are often treated using:
(what type of energy)

What is a common treatment technique of pituitary lesions?

The disadvantages of a vertex field is that it often exits in the _________ and the ___________.

In a typical CSI setup, to avoid having the caudal margin of the lateral brain fields diverge into the cephalad aspect of the posterior spinal field, the foot of the couch is turned:

Of all childhood brain tumors, medulloblastoma represents about ______%

The most commonly occurring cancer in the US is ________ cancer.

A lung boost is often delivered via:

Tumors in the lower two-thirds of the esophagus can be boosted via a _______ and two _________ oblique fields.

The number of US women who will develop breast cancer is approximately:

The regional lymph nodes in breast cancer are the:
(3)

To avoid beam divergence from the tangential fields into the supraclavicular field, the foot of the couch is turned (kicked) ________ from the collimator/gantry.

To avoid beam divergence into the lung by the tangential fields, the central axes of the tangential fields can be separated by slightly more than ______ until the deep margins become _________.

The most important considerations to avoid radiation-induced pneumonitis are:
(3)

What is the most common type of glioma?

What is the origin of gliomas?

What is the formula used to determine how many degrees the table will need to be kicked?

What are the 3 traditional whole brain set-ups?

What are the borders of a generic whole brain set-up?

Craniospinal fields are often used to treat:
(2)

Other than transverse myelitis, name another radiation induced spinal injury:

The gantry angles for tangent fields are usually separated by _______°.

When treating the supraclavicular LN of a breast cancer patient, the gantry is angled _____° away from the side of the cancer.

A ________ is a plot of target or normal structure volume as a function of dose.
Represents the amount of dose (an absolute value) received by a percentage or fraction of a structure like an organ (a relative value) 

What are the 3 classic phases of lung cancer treatment?

Name that fractionation:
Irradiating a patient twice daily with a smaller than normal daily dose, making it possible to deliver 15-20% more dose over the same period of time.

Name that fractionation:
Delivering the same dose over a shorter period of time.

What are the two most important factors for immobilization with head & neck cancer?

The average depth of lymph nodes is ______ to ______ cm.

The tissue to air ratio (TAR) at Dmax is also known as the _________.

Identify & describe each whole brain set-up (including borders)

The _______ is defined as the ratio of dose at a specified point in tissue (or in a phantom) to the dose at the same distance in the beam at a reference depth, usually 5 cm.

When using a SCV field to treat breast cancer the gantry is angled 15° to avoid inclusion of the:
(3)