Quiz 4 Flashcards
RT is used in head and neck (H&N) treatments because _____ of the body’s LNs are in the H&N but sensitive organs are also in this area
1/3
2 clinical presentations of H&N disease
Endophytic
Exophytic
Growth pattern that invades within, more aggressive
Endophytic
Noninvasive neoplasm that projects out from epithelium, usually presents with raised borders on skin
Exophytic
4 diagnosis tools for H&N disease
Laryngoscopy
Palpation
Fiberoptic endoscopy
Biopsy
Gingiva
Gums
Triangular-shaped area behind molars
Retromolar trigone
7 parts of the oral cavity
Lips Buccal mucosa Gingiva Retromolar trigone Hard palate Floor of mouth Anterior two thirds of tongue
3 lymphatic drainage sites of the lips
Submandibular nodes
Preauricular
Facial nodes
2 lymphatic drainage sites of the buccal mucosa
Submaxillary nodes
Submental nodes
2 lymphatic drainage sites of the gingiva and retromolar trigone
Submaxillary nodes
Jugulodigastric nodes
2 lymphatic drainage sites of the hard palate and anterior two thirds of the tongue
Submaxillary nodes
Upper jugular nodes
2 lymphatic drainage sites of the floor of the mouth
Submaxillary nodes
Middle and upper jugular nodes
4 parts of the oropharynx
Base of the tongue
Tonsillar fossa
Soft palate
Pharyngeal walls
3 lymphatic drainage sites of the base of the tongue
Jugulodigastric nodes
Low cervical
Retropharyngeal nodes
2 lymphatic drainage sites of the tonsillar fossa
Jugulodigastric nodes
Submaxillary nodes
3 lymphatic drainage sites of the soft palate
Jugulodigastric nodes
Submaxillary
Spinal accessory nodes
3 lymphatic drainage sites of the pharyngeal walls
Retropharyngeal nodes
Pharyngeal
Jugulodigastric nodes
2 lymphatic drainage sites of the retropharyngeal nodes of the nasopharynx
Superior jugular nodes
Posterior cervical nodes
2 lymphatic drainage sites of the sinuses
Retropharyngeal nodes
Superior cervical nodes
3 parts of the larynx/voice box
Glottis
Subglottis
Supraglottis
2 lymphatic drainage sites of the subglottis
Peritracheal nodes
Low cervical nodes
3 lymphatic drainage sites of the supraglottis
Peritracheal nodes
Cervical submental
Submaxillary nodes
Ear pain
Otaglia
Don’t know where cancer (CA) arose from, undifferentiated; treat like nasopharynx
Unknown primary
Pillar
Arch
Taste buds at back of tongue
Circumvallate papilla
“Spit trap”
Vallecula
4 H&N position and immobilization devices
Immobilization aquaplast mask: nose and zygomatic arches fit tightly but not on eyes; have minimal bolus effect and increase surface dose
Bite block
Arm stretcher
Neck sponge: B or C head sponge
Keep tongue still or out of field
Bite block
Spinal cord of great concern at 4500 cGy; electrons posterior and photons anterior
Anterior triangles
2 H&N interstitial sources
Iridium
Iodine
Average head diameter and SSD
Diameter: 15 cm
SSD: 92.5 cm
___-___ MV photons for oral cavity treatment
4-6 MV
Most common aerodigestive tract carcinomas
Oral cavity
Combined organs and tissues of respiratory tract and upper digestive tract including lips, mouth, tongue, nose, throat, vocal cords, and part of esophagus and windpipe
Aerodigestive tract
4 oral cavity maligancies
Tongue disease usually in lateral borders near middle or posterior 1/3 of tongue
Floor of mouth or anterior surface any side of midline
Lips and gum treated similar to skin CA
Retromolar trigone, hard palate (rare), buccal mucosa, and gingival ridge
Gingival ridge
Gumline
Oral cavity superior and lower borders
Superior = skin-vermillion junction to posterior border of hard palate
Down to circumvallate papillae/base of tongue
Where lips and skin connect
Skin-vermillion junction
Oral cavity opposed lateral and boost dose
Lateral: 4500 cGy
Boost: 65-70 Gy
Oral cavity T3-T4 dose
Up to 80 Gy
Oral cavity IMRT dose to primary lesion
Over 2 Gy
Oral cavity superclav field dose
45-5000 cGy
Parotid TD5/5
3200 cGy
Level of oropharynx
C2-C3
5 disease sites of the oropharynx
Tonsils most common Base of tongue Lateropharyngeal walls Soft palate Uvula
Upper, anterior, inferior and posterior oropharynx borders
Upper: zygomatic arch, shield ear
Anterior: clinically 2 cm beyond tumor
Inferior: thyroid notch
Posterior: cover cervical LNs
Initial dose, dose with posterior triangles, and dose with final boost for the oropharynx
Initial: 4500 cGy
Posterior triangles: 6000 cGy
Boost: 65-75 Gy
Higher dose per fraction to reduce number of weeks patient has to be treated
Accelerated
C3-C6, epiglottis to cricoid cartilage
Lower posterior pharyngeal wall, posterior cricoid area, and pyriform sinuses
IMRT and arcing field VMAT
Hypopharynx
Sinuses on either side of larynx
Pyriform sinuses
Preop and postop hypopharynx dose
Preop: 40-4500 cGy
Postop: 60-65 Gy
Doesn’t have direct drainage to LN chain and doesn’t commonly metastasize
Larynx
Space between vocal cords, 65% of larynx CAs here
Glottis
Above vocal cords
Supraglottis
Below vocal cords
Subglottis
Treat larynx with ___x___ or ___x___ lateral or anterior oblique fields for early stage disease
5x5 or 6x6
Treat larynx with ___-___MV, ___cm of flash anteriorly
4-6MV
1cm
Less than 200 cGy per fraction to larynx results in greater risk of recurrence; treat with over ___-___ cGy per fraction
200-225 cGy
BID larynx treatment dose and dose per fraction
7440-7900 cGy
240 cGy per fraction
T1, T2, and T3 larynx disease dose
T1: 66 Gy
T2: 70 Gy
T3: 6850-7075 cGy (advanced disease)
Larynx superclav dose
46-50 Gy
Early stage larynx port superior, inferior, anterior, and posterior borders
Superior: top of hyoid bone
Inferior: cricoid cartilage/lower border of C6
Anterior: 1-1.5cm flash/shine
Posterior: early no LN cervical, anterior to vertebral body
Arytenoid
Cartilage
Lies at zygomatic arch to EAM, extends inferiorly down to mastoid tip behind nasal cavity above level of soft palate
3D and IMRT
Nasopharynx
Initial dose and boost dose for T1 and T2 nasopharynx disease
Initial: 5000 cGy
T1: 6500 cGy
T2: 70-75 Gy
Take similar skin to replace skin where disease caused it to be removed
Interoplation flap
Doesn’t repair/regrow
Don’t often metastasize but are locally invasive and can create significant problems for patient
Combined modality treatments: surgery, RT, and lipid soluble chemo to pass blood-brain barrier (BBB)
Central nervous system (CNS) malignancy
4 CNS treatment techniques
Radical surgery is the best chance for a good outcome
Debulking surgery followed by RT to residual tumor that can’t be completely excised, positive margins, or inaccessible tumor and metastatic lesions
RT
Stereotactic radiosurgery-Gamma knife
4 things RT dose for CNS disease depends on
Tumor type
Grade
Patterns of recurrence
Radio-responsiveness
2 reasons whole-brain irradiation for CNS disease is done, setup like H&N treatments
Mets
Meningeal disease
3 layers of the meninges from inside out
Pia
Arachnoid
Dura mater
Curative CNS dose and palliative dose and number of treatments
Curative: 50-60 Gy
Palliative: 30-3750 cGy in 10-15 treatments
Brain TD5/5
4500 cGy
Brainstem and posterior fossa dose and dose in fractions
5500-6000 cGy in fractions less than 200 cGy
Precision very important because high dose to small area, less fractions than SRT
Stereotactic radiosurgery (SRS)
SRS brain mets dose and fractions for small number of lesions (less than 4)
20-30 Gy in 1 fraction
SRS astrocytoma dose and fractions
1600-5000 cGy in 1-2 fractions
Usually nonmalignant bundle of vessels in brain, can cause strokes and is the leading cause of stroke in yound people
Arteriovenous malformation (AVM)
SRS AVM dose, radiation clogs vessels and they begin to deteriorate
20-25 Gy up to 12000 cGy
Cobalt and photon SRS without linac
Cobalt: gamma knife
Photon: cyberknife
2 diseases craniospinal irradiations (CSI) are commonly used for in kids
Pediatric germinomas
Astroblastomas
Two opposed lateral fields for whole brain with spinal fields (1-2 depending on how long patient is)
Prone and tilt chin up to avoid oral mucosa from PA spine field divergence
Craniospinal irradiation (CSI)
Overlapping spine field with whole brain treatments require us to do ______ and _______ rotation to match angle of divergence; overlapping PA spine fields require us to do __________ to avoid over radiating spinal cord
Couch, collimator Gap calculation (calc)
Rotate cranial field to match divergence from PA spinal field (SSD)
Collimator rotation
Rotate PA spine field to account for divergence from cranial fields (SAD)
Couch kick
CSI dose, dose for high risk recurrence patients, and boost to primary brain site
Dose: 3000 cGy
High risk: 3600 cGy
Boost: 5400-5580 cGy
Gap calc
(1/2)(L1)(d/SSD) + (1/2)(L2)(d/SSD)
Opposite over adjacent
Inverse tangent function (tan^-1)
Collimator angle formula
tan^-1(L1/SSD)
Couch kick formula
tan^-1(L1/SAD)
Migration of gap between treatment fields through treatment course; move junction on neck to reduce areas receiving radiation from overlap
Feathering
How far, at what dose, and what is the total dose that a CSI should be feathered?
Move 1 cm every 1000 cGy, total of 3000 cGy
5 CNS malignancies
Gliomas Medulloblastoma Craniopharyngioma Meningioma Lymphoma of the CNS
Pituitary gland dose and dose for tumors over 2cm
Dose: 45-5400 cGy
>2cm: up to 5400 cGy
2 digestive system malignancies
Colorectal
Pancreatic
Most common gastrointestinal malignancy, best prognosis
Colorectal
4 colorectal treatment techniques
Surgery: treatment of choice
Adjuvant or neoadjuvant RT in conjunction with chemo
Endocavitary RT/sphincter-preserving method/technique
Chemo
Curative for patients with low to middle third rectal CAs, early stage disease confined to bowel wall
Lidocaine relaxes sphincter, proctoscope inserted for doctor to see lesion; hose inserted and electrons administered
Don’t get deep dose with electrons
Endocavitary RT
Sphincter-preserving method/technique
Number of electron treatments with probe, dose per treatment, total dose, and time between treatments for endocavitary RT/sphincter-preserving method/technique
4 electron treatments at 3000 cGy = 12000 cGy total, treatments separated for 2 weeks
2 colorectal chemo regimens
5FU and leucovorin
FOLFOX
FOLFOX
5FU
Leucovorin
Oxiplatin
EBRT ___-___ weeks before endocavitary RT/sphincter-preserving method/technique which is given as a boost
7-8 weeks
___ colorectal cure rate with endocavitary RT/sphincter-preserving method/technique
90%
Colorectal dose and coned down dose
Dose: 4500 cGy
Coned: 50-55 Gy
Small bowel (SB) TD5/5
40 Gy
Colorectal IMRT and VMAT dose for microscopic and gross residual disease (give higher dose because it’s more conformal)
Microscopic: 60 Gy or more
Gross residual: 70 Gy or more
Colorectal treatment fields encompass ______________ and ______ with _______ field techniques or IMRT/VMAT
Primary tumor volume, LNs
Shrinking
2 LNs encompassed by colorectal treatment fields
Internal iliacs
Pre-sacrals
2 colorectal field arrangements determined by anterior structures and if they need dose (wedge with toes to AP and heels to PA)
AP/PA and 2 laterals
PA and 2 laterals
3 ways to get SB out of treatment field
Full bladder
Stomach/belly board
False tabletop
Linac in surgery, treat are with disease
Mobile accelerators that provide high energy electrons
Intraoperative RT (IORT) Precision therapy
IORT dose in single fraction to tumor bed
1000-1200 cGy
With 4 field colorectal treatments, _______ structures (bladder, etc.) receive more dose
Anterior
2 multimodality esophageal CA treatment techniques
Surgery: superior/upper connected to oral cavity leading to decreased quality of life (QOL)
Radiation and chemo: non-surgical treatment of choice; IMRT and VMAT boost
2 most common sites of esophageal disease
Middle esophagus
Distal esophagus
Most patients have locally advanced or metastatic esophageal disease leading to the use of ______ fields/portals because of potential for longitudinal spread
Large
Can see lesions 5cm from primary
Skip lesions
Upper esophageal treatment fields
2 anterior obliques
______ position is more comfortable but gravity can pull esophagus closer to spinal cord, ______ less comfortable but allows more distance between esophagus and spine
Supine, prone
Initial dose and dose per day to esophagus with AP/PA and obliques and first and second boost dose
Initial: 4500 cGy
Per day: 180-200 cGy
1st: 5000 cGy
2nd: 60-70 Gy
Esophageal dose for just RT and no chemo and dose with RT and chemo
RT: 65 Gy
Chemo: 50 Gy
Esophageal tumor infiltrates at tracheobronchial tree can lead to a fistula close to aorta that can rupture so we must lower the fractionated dose to _____cGy per day and use more fractions to still get close to total dose
150 cGy
2 pancreatic CA techniques
Surgery
RT and chemo preferred treatment for locally advanced or unresectable disease
Treatment of choice for pancreatic cancer
Remove head of pancreas, duodenum, gallbladder, common bile duct, distal stomach, and possible vagotomy
Can double median survival but most tumors are unresectable due to advanced disease
Whipple procedure
Most important diagnostic tool of pancreatic CA
CT
4 field technique for pancreatic cancer; supine, arms above head
AP/PA and 2 laterals
6 dose limiting structures contained in the area of the pancreatic treamtent field
Liver Kidneys Heart Spinal cord SB Stomach
Liver, kidneys, heard, spinal cord, and stomach TD5/5
Liver: 3000 cGy Kidneys: 2300 cGy Heart: 4000 cGy Spinal cord: 4700 cGy Stomach: 5000 cGy
Pancreatic dose and dose per fraction; worry about kidneys on laterals
45-50 Gy at 180 cGy per fraction
AP and inferior pancreatic margins
AP: T11-L3, adequate margin; T12-L1 vessels
Inferior: L2-L3, block kidneys
Pancreatic EBRT and IORT dose
EBRT first: 5040 cGy
IORT: 10-25 Gy (20 Gy)
3 gynecological malignancy
Uterine
Cervix
Endometrial
Fields for gynecological malignancies
4 field AP/PA and 2 laterals
Primary tumor and regional LNs
Distal end of anal canal forming a transitional zone between the epithelium of the anal canal and perianal skin
Anal verge
7 structures to worry about during the treatment of gynecological malignancies
Fleshy portion over pubis bone Clitoris Urethra meatus Labia major and minor Ovaries Cervix Endometrium
Obese patients whose large abdomen marks move a lot, stomach creates _______ and skin breakdown occurs under fold
Bolus
Will not treat over ______cGy if SB is in field
5000 cGy
Treatment for early stage (carcinoma in situ, 0, IA2) cervix disease based on involvement and treatment for childbearing
Total abdominal hysterectomy (TAH) and vaginal cuff
Conization
Inoperable early stage cervical disease in one implant with tandem and ovoids dose
45-55 Gy
Inoperable early stage cervical disease in one or two implants with tandem and ovoids dose for stage IA2
60-75 Gy
Initial EBRT dose for bulky/later stage cervix disease IIB3 and 4A; brachytherapy implant dose to low volume disease and bulky disease
EBRT: 40-50 Gy (45 Gy)
Low volume: 70 Gy
Bulky: 85-90 Gy
Ensure outer dose to cervical area with this block mounted in middle of AP/PA field allows dose to peripheral structures like LNs
Pogo
Step wedge
Midline block
Cervix superior, inferior, lateral, anterior, and posterior borders
Superior: AP/PA L4-L5
Inferior: BIT, BOF, or 4 cm below lowest extent of disease
Lateral: 1.5-2 cm lateral of bony pelvis
Anterior: lateral field anterior to symphysis pubis
Posterior: transect sacrum at S3-S4
2 cm lateral to tandem and 2 cm superior to cervical oss or end of tandem, point where uterine vessels cross ureters (dose-limiting structure)
Point A
3 cm lateral to point A
Point B
1 cm lateral to point B
Point P
At point of foley catheter
Bladder
5 mm posterior to vaginal wall
Rectum
Lining of uterus
Endometrium
Stage IA, grade I (early stage) endometrial disease treatment
Hysterectomy only, encompassed in removed area
Stage IB, grade I, II endometrial disease post TAH brachytherapy dose
60-70 Gy or 5-7 Gy to 0.5 cm in three applications
Stage IC or higher, grade III endometrial disease post TAH external and implant dose
External: 45-50 Gy
Implant: 80 Gy
Stage IC or higher, grade III endometrial disease post TAH 4 field dose, boost dose for gross involvement, and brachytherapy boost to endometrial cavity with Heyman capsules and tandem
4 field: 50-60 Gy
Boost: 65 Gy
Brachytherapy: 75-90 Gy
If hysterectomy, no tandem or Heyman capsules, use ______ and ________
Ovoids
Vaginal cylinder
Bladder and rectum TD5/5
Bladder: 6500 cGy
Rectum: 6000 cGy
When treating endometrium, keep badder and rectum at this lower dose
60-75 Gy
Stage III, IV endometrial disease EBRT dose, brachytherapy dose, and bulky disease dose with shield
EBRT: 50 Gy
Brachy: 75 Gy
Bulky: 100 Gy
2 structures wing blocks during endometrial treatments decrease dose to
Bone marrow
Femoral heads
Post op whole abdomen EBRT dose and boost to paraaortic and pelvic LNs for ovarian disease
EBRT: 2550-3000 cGy
Boost: 40-50 Gy
7 ways to increase anterior dose when treating vulva to minimize dose to femoral heads and rectum
Anterior weighting pulls dose anteriorly
Lower anterior energy and high posterior energy pushes dose anteriorly
Anterior electron field
Anterior bolus
Partial transmission blocks
Narrow PA fields to protect femoral head and neck by closing in beam but may need to supplement inguinal LNs
IMRT spares healthy tissue
External, treat with wide excision and EBRT
Primary site and pelvic LNs
Frog-leg to reduce bolus from folds and skin breakdown
Wire scars/palpable nodes for gross disease and bolus over scar
RT, surgery for recurrence
Vulva CA
Brachytherapy alone dose and EBRT first and brachytherapy dose for primary or macrodisease for vulva CA
Brachy: 60 Gy
EBRT: 45-50 Gy, brachy: 65-80 Gy
Midline block when treating vulva after ___Gy for early invasive disease and after ___Gy for stages IIB or higher to get tumor dose to critical structures as close as possible
20 Gy, 40 Gy