Assignment 2

Question 1

List the four most common primary sites from which metastases can occur:

Answer 1

lung, prostate, breast, and kidney

Question 2

TD 5/5: bladder

Answer 2

6500 cGy

Question 3

TD 5/5: rectum

Answer 3

6000 cGy

Question 4

TD 5/5: testes

Answer 4

100 cGy

Question 5

TD 5/5: ovaries

Answer 5

200-300 cGy

Question 6

TD 5/5: prostate

Answer 6

7000 cGy

Question 7

TD 5/5: uterus

Answer 7

10000 cGy

Question 8

TD 5/5: vagina

Answer 8

9000 cGy

Question 9

TD 5/5: femoral head/neck

Answer 9

5200 cGy

Question 10

TD 5/5: small bowel

Answer 10

4000 cGy

Question 11

TD 5/5: colon

Answer 11

4500 cGy

Question 12

How can the patient be positioned during CT Sim so that the small bowel is minimized in the treatment field?

Answer 12

the patient can be positioned prone on a bellyboard with a full bladder

Question 13

when should the patient’s bladder be full or empty when treating the whole pelvis?

Answer 13

prostate: full
bladder: empty
ovarian: full

Question 14

how can the bladder be localized on imaging?

Answer 14

Use Cystografin contrast via a Foley catheter

Question 15

how can the rectum be localized on imaging?

Answer 15

Use a radiopaque rectal marker, or a rectal tube with barium

Question 16

how can the vagina be localized on imaging?

Answer 16

Use a radiopaque vaginal marker, or a tampon dipped in barium

Question 17

how can the prostate be localized on imaging?

Answer 17

use fiducials

Question 18

What is the cisterna chyli and why is it important?

Answer 18

• It is a sac-like lymphatic organ anterior to L1/2 thought to be the origin of the thoracic duct, which is the main duct that collects lymph from the lower part of the body.

Question 19

what is the vertebral level for the bifurcation of the abdominal aorta

Answer 19

L4

Question 20

where does the spinal cord start?

Answer 20

foramen magnum

Question 21

List the type of brachytherapy procedure used in the treatment of uterine cervix.

Answer 21

LDR or HDR using Tandem & Ovoid (aka. Colpostat) applicators (e.g. Fletcher Suite)

Question 22

What are the most common applicators used?

Answer 22

Tandem & Ovoid (aka. Colpostat) applicators (e.g. Fletcher Suite)

Question 23

What 2 radioactive materials are used in the treatment of the uterine cervix? What is the half life for each?

Answer 23

Cesium 137: 30 years (used in LDR)

Iridium 192: 74 days (used in HDR)

Question 24

What type of brachytherapy procedure is used in the treatment of prostate cancer?

Answer 24

• Interstitial – permanent seed implants

* Iridium 192 – temporary needles

Question 25

What 3 radioactive materials are used in prostate brachytherapy? List the half life of each.

Answer 25

* Iodine 125 (permanent) – 59.4 days * Palladium 103 (permanent) – 17 days * Iridium 192 (temporary) – 74 days * Gold 198 (permanent) – 2.7 days

Question 26

What is a Fletcher Applicator? How are they used?

Answer 26

• Tandem & Ovoids (aka. Colpostats). A tandem is inserted through the cervix into the uterus, and two ovoids are inserted into the lateral vaginal fornices. Both are stabilized with sterile gauze packing, which also serves to displace the rectum and bladder from the sources.

Question 27

What is Point A and Point B?

Answer 27

• The anatomic points used historically for cervical and uterine treatment are points A and B. Point A, where the prescription dose is specified, is located 2 cm superior to the top of the ovoids along the tandem and 2 cm lateral to the tandem in the plane of the applicator. It is approximately where the uterine arteries and the ureters intersect, and is chosen to ensure that the part of the cervix located between point A and the applicator receives the prescription dose (at a minimum). Point B, located 2 cm superior to the top of the ovoids and 5 cm lateral to the patient midline, represents where the parametrial nodes are.

Question 28

list the accompanying disease with the following tumor marker: CEA

Answer 28

colon, breast, SCLC, and rectum

Question 29

list the accompanying disease with the following tumor marker: serum acid phosphatase

Answer 29

prostate

Question 30

list the accompanying disease with the following tumor marker: AFP

Answer 30

testes, ovaries, and liver

Question 31

the histological type of cervix cancer is

Answer 31

squamous cell carcinoma

Question 32

what lymph nodes are at risk in cancer of the cervix?

Answer 32

Obturator, internal iliac, and external iliac

Question 33

what is the most radiosensitive organ in the female reproductive system?

Answer 33

ovaries

Question 34

what is the dose prescription for cervical cancer?

Answer 34

180 cGy/ fraction x 25 fx = 4500 cGy

Question 35

in ovarian cancer, how does the disease spread?

Answer 35

seeding via cells suspended in abdominal fluid (ascites)

Question 36

when treating ovarian cancer AP/PA, what critical organ (s) must be blocked in the field?

Answer 36

the kidneys

Question 37

what is the histolgical type of endometrial cancer?

Answer 37

adenocarcinoma