Assessing Leakage Workloads of Medical Linear Accelerators

ASSESSING LEAKAGE WORKLOADS OF MEDICAL LINEAR

ACCELERATORS FOR IMRT AND TBI TECHNIQUES

A Thesis

submitted to the Faculty of the

Graduate School of Arts and Sciences

of Georgetown University

in partial fulfillment of the requirements for the

degree of

Master of Science

in Health Physics

By

James R. Jordan, B.S.

Washington, DC

December 10, 2007

ii

Thanks to all people and institutions that provided data for this thesis specifically:

Brad Murray of Cross Cancer Institute

Ralph Young of Martin Memorial Cancer Center

Kathryn Wall and Cara Sullivan of Rock Hill Radiation Therapy Centre

Richard Emery and Dr. Anthony Berson of St. Vincent’s Comprehensive Cancer Center

Julius V. Turian of University of Illinois Medical Center

Allan Caggiano of Holy Name Hospital

Marc S. Miner of Hughes Cancer Center of Pocono Medical Center

St. Joseph Hospital of Orange, California

Wolfgang Tomé and Bhudatt Paliwal of University of Wisconsin Hospital

And all other people and institutions that wished to remain nameless.

Many thanks,

James R. Jordan

iii

ASSESSING LEAKAGE WORKLOADS OF MEDICAL LINEAR

ACCELERATORS FOR IMRT AND TBI TECHNIQUES

James R. Jordan, B.S.

Thesis Advisor: James E. Rodgers, Ph.D.

ABSTRACT

Current estimates for leakage workloads are not well quantified for Intensity Modulated

Radiation Therapy (IMRT) and Total Body Irradiation (TBI) treatments. When analyzed

on a large scale, using a large sample, a well defined leakage workload may be

established. A database of 17 cancer treatment centers and 73 linear accelerators were

used to make the assessment. There were 374,003 total treatments, with 213,757 low

energy (4 and 6 MV) treatments, 106,343 of which were IMRT and 149,730 high energy

(15, 16, 18, and 20 MV) treatments, 64,138 of which were IMRT. There were 184 TBI

treatments, with 98 being low energy and 86 being high energy. The numbers are too

scant to make any statements about the contribution TBI makes to workload, there is

more than enough data to estimate the IMRT contribution to leakage workload. An

IMRT factor, CI, of 5.1 may be used for low energy photon calculations, and a CI of 4.4

may be used for high energy photon calculations, where CI is:

conv

IMRT

IMU

MUC =

.

iv

TABLE OF CONTENTS

Introduction …………………………………………………………………………...... 1

Chapter I: Material and Methods ..……………………………………………………... 4

Chapter II: Results …………………………………………………………………..…. 9

Chapter III: Discussion ……………………………………………………………….. 15

Appendix ………………………………………………………………………………. 26

Bibliography ………………………………………………………………………… 122

1

INTRODUCTION

Due to its smaller field sizes and the number of segments used per field, Intensity

Modulated Radiation Therapy (IMRT) uses many more monitor units (MU) per delivered

dose (usually measured in centigray abbreviated cGy) than does conventional external

beam radiation treatment. This does not have an effect on the IMRT workload for the

primary barrier or for scatter as demonstrated by Rodgers (8), but the increased beam-on

time can greatly increase the leakage of radiation from the head of the medical linear

accelerator and secondary barrier thickness requirements. Thus, the primary barrier

IMRT Workload (WIMRT) alone, in dose per week, is not sufficient to determine the

contribution of IMRT to the total leakage-radiation workload. WIMRT must be multiplied

by some factor in order to account for its increased MU per cGy in order to calculate its

full contribution to the leakage workload (WL). To find this factor, which the National

Council on Radiation Protection and Measurements (NCRP) in NCRP Report Number

151 calls the IMRT factor or CI, a ratio is taken of the of the MU per cGy of prescribed

dose for IMRT and the MU per cGy for conventional treatments (6):

∑=i

ipre

i

IMRTD

MUMU

)(

so,

conv

IMRT

IMU

MUC =

.

2

Where MUIMRT is measured in MU/cGy, and CI is a dimensionless quantity. Since

MUconv is conservatively defined as 1 MU/cGy, in most cases CI is the same value as

MUIMRT.

Just as IMRT disproportionately affects WL, Total Body Irradiation (TBI) does as

well, due to the inverse square law. Conventional workloads (Wconv) are calculated at a

distance of one meter from x-ray target to the patient, and TBI is treated at much greater

distances, up to five meters, with the TBI workload (WTBI) normalized to one meter (6).

This will greatly increase the leakage radiation contribution of TBI, since the amount of

MU per delivered dose is increased by a power of two for any increase in distance

between the x-ray target and patient.

Followill et al. calculated an IMRT factor of 3.4 MU/cGy for Varian Multi-leaf

Collimators (MLC) at 6 Megavolts (MV) and 2.8 MU/cGy at 18 and 25 MV. For Nomos

Tomotherapy an IMRT factor of 9.7 MU/cGy at 6 MV and 8.1 MU/cGy at 18 and 25 MV

was calculated. These calculations fall in line with the NCRP value of 2 to 10 (1, 6);

however, their study was limited to four patients using conventional unwedged

treatments, who were also planned using the MLC and tomotherapy IMRT techniques.

Mechalakos et al. also examined the workload for IMRT. They found an increase

in MU per week on their Varian 2100C machine with photon energies of 6 and 18 MV

using IMRT compared to two other machines (a Siemens Mevatron KD with photon

energies of 6 and 15 MV and a Varian 600C with photon energy of 6 MV), which were

limited to conventional treatments only. Their IMRT factor was between 2.2 to 2.5 (4).

3

This study was conducted with one year of data, but was limited in scope with only a

single machine performing IMRT.

Since an increased WL may translate into an increased amount of secondary

shielding needed to protect radiation workers and the public, it is very important to

carefully ascertain the CI and find the increase in leakage due to IMRT. Other studies

have found increases in workload from IMRT and TBI, but the scope of these studies was

not very broad. In this study, with a wide range of accelerators and treatment types, I

hope to more firmly establish the contributions of IMRT and TBI to the total leakage

workload.

This paper will set values for the CI contribution to the WL for the increased

leakage radiation in IMRT and TBI. I hypothesize that current estimates for leakage

workloads are not well quantified for IMRT and TBI treatments, but when analyzed on a

large scale, using a large sample, a well defined CI may be established.

4

CHAPTER I: MATERIALS AND METHODS

In this study, data was collected from seventeen radiation treatment centers,

which included 71 Varian accelerators (which included CL 6/100, 600C, 600C/D, CL

1800, 2100C, 2100C/D, 21EX, 2300C/D, and 23EX) and almost 375,000 treatment fields

of a combination of conventional unwedged, conventional wedged, IMRT, and TBI

treatments at energies of 4, 6, 15, 16, 18, and 20MV. The data was organized by Varian

using an InfoMaker report to collect the data from the treatment planning systems and

entered into Excel spreadsheets where it could be analyzed. The data that was collected

included the field, treatment time, gantry angle, energy mode, MU, dose, and accessory

used (wedge, cone, etc.).

The collected data was separated by hospital system and by individual machine.

Individual treatments that were IMRT or TBI were identified. It was then analyzed by

energy mode for the conventional MU per cGy, IMRT MU per cGy, TBI MU per cGy,

and the fraction of treatments that were IMRT was noted.

The data was analyzed by multiple methods. First, for all categories a simple

mean was computed by:

n

n

i i∑ == 1µ

µ

with the standard deviation being:

5

( )

n

n

i i

2

1∑ =−

=µµ

σ.

For an unbiased estimator of the standard deviation for a small sample n-1 is used in the

denominator. However, with the large sample sizes involved in this study, n-1 is not

significantly different than n.

The mean MU/cGy was calculated for each gantry angle used in the treatment for

conventional treatments with and without wedges, IMRT, and TBI at each individual

energy for all 73 machines in which the treatment applied. This was done simply by

summing all MU/cGy and dividing by the total number of occurrences. The IMRT, TBI,

and conventional (which includes wedges) means are displayed in Tables 2.46 through

2.58 in the appendix for machines that conducted IMRT or TBI treatments. Machines

that were not used for IMRT or TBI had means calculated for their individual energies

treated, but they are not represented in this report.

Second, the MU/cGy data for IMRT treatments was placed into value bins in

order to be able to graph the results. To do this, bins of different MU/cGy values were

created. The total number of these occurrences were created and then normalized to 100.

The width of each bin was charted for its relative weight, and the mid-point of each bin

was noted. An example of the collected data is shown in Table 1.1.

6

Delta 0.5

Bin Unit 1 6X IMRT

Unit 1 6X IMRT

0 n Ni wi b'i Ni*wi*b'i Ni*wi Ni*wi*(b'i-mean(0-15))^2

0.5 0 0.0 1.00 0.25 0.00 0.00 0.00

1 0 0.0 1.00 0.75 0.00 0.00 0.00

1.5 0 0.0 1.00 1.25 0.00 0.00 0.00

2 20 2.4 1.00 1.75 4.16 2.38 14.62

2.5 174 20.7 1.00 2.25 46.50 20.67 81.10

3 124 14.7 1.00 2.75 40.50 14.73 32.30

3.5 74 8.8 1.00 3.25 28.56 8.79 8.46

4 116 13.8 1.00 3.75 51.66 13.78 3.19

4.5 75 8.9 1.00 4.25 37.86 8.91 0.00

5 24 2.9 1.00 4.75 13.54 2.85 0.77

Table 1.1. Chart of collected data.

The first bin is all occurrences that are greater than or equal to 0 MU/cGy through

all occurrences less than 0.5 MU/cGy. The second bin is from 0.5 to less than 1.0. Delta

is the smallest bin size. The number of occurrences is denoted by n. Ni is the number of

occurrences normalized to 100 total occurences. The bin weight calculated by

subtracting the bottom of the bin from the top of the bin and dividing by the smallest bin

width is wi. The midpoint of each bin is b’i. The unit number (Unit 1 in Table 1.1) is the

tracking number for the machine at the facility being analyzed. Each facility has a unique

hospital serial number (HSN) and each machine analyzed in a facility has a number

assigned as a resource serial number (RSN) starting at one for each facility, e.g., HSN 1,

RSN 1. A table on page 12 shows each machine that conducted IMRT treatments, the

energies at which the machine conducted IMRTs, and the page where the data is located.

These results were then graphed. The abscissa is the value of mid-point of the

bin, and the ordinate is the number of occurrences for that bin. This can be seen in Figure

7

1.1.

RSN 1 6X IMRT

0.0

5.0

10.0

15.0

20.0

25.0

0 1 2 3 4 5

bins of MU/cGy

Nu

mb

er

of

Occu

rren

ces,

N

RSN 1 6X IMRT

Figure 1.1. Frequency distribution of MU/cGy plotted versus bin mid-point value.

A table was also created of means and standard deviations with differing

maximum cutoffs. Since the means and standard deviations are greatly affected by

outliers, this will give the ability to disregard higher numbers for anomalous high values.

An example of this table is shown in Table 1.2.

The mean becomes:

∑

∑

=

=′

=n

i

n

i

wiNi

ibwiNi

1

1

*

**µ

and the standard deviation becomes:

8

( )

∑

∑

=

=−′

=n

i

n

i

wiNi

ibwiNi

1

2

1

*

** µσ

.

mean for indicated range RSN 1 6X IMRT

mean(0-15)= 4.23

mean(0-25)= 4.23

mean(0-50)= 4.94

mean(0-200)= 4.94

mean(0-1500)= 4.94

stdev(0-15)= 2.33

stdev(0-25)= 2.33

stdev(0-50)= 4.76

stdev(0-200)= 4.76

stdev(0-1500)= 4.76

Table 1.2. Table of means and standard deviations at different cutoffs of MU/cGy.

As mentioned in the introduction, I set out to analyze CI on a large sample group. I

believe I have achieved this by using a database of 17 cancer treatment centers and 73

linear accelerators. There were 374,003 total treatments, with 213,757 low energy (4 and

6 MV) treatments, 106,343 of which were IMRT and 149,730 high energy (15, 16, 18,

and 20 MV) treatments, 64,138 of which were IMRT. There were 184 TBI treatments,

with 98 being low energy and 86 being high energy. All 374,003 treatments have several

data recorded besides MU and dose, these include machine model, accessories used

(wedge, cone, et cetera), field identification and name, reference identification and name,

gantry angle, energy mode, patient and session serial number, treatment technique, and

treatment date and time.

9

CHAPTER II: RESULTS

Figures 2.1 through 2.44 in the appendix show the graphs of all machines that

performed IMRTs. Each figure has a corresponding table of means and standard

deviations at MU/cGy cutoffs of 15, 25, 50, 200, and 1500 MU/cGy. These cutoffs are

useful for determining the most useful data to use. For example, if IMRT set-up fields

were included with the data, then the extremely low dose (nominally zero assessed to

these fields) causes the MU/cGy value to be inordinately high and these numbers may be

discarded since they are fictitiously high. The data in the tables below represent the

number of MU/cGy of IMRT treatments which represents the MUIMRT. The IMRT factor

or CI may be found by dividing the MUIMRT by the MUconv. A MUconv of 1 may be used

for conservative values of CI which also makes MUIMRT equal to CI for conservative

estimates.

The overwhelming majority of data, before being analyzed whether there is a

need to restrict the ranges to lower cutoffs, show an IMRT factor within the NCRP

suggested value range of between 2 and 10. All values above the range noted in NCRP

151 will be discussed here.

The first elevated values, as seen in Tables 2.4 and 2.5, are from HSN 2, a

hospital cancer center, RSN 4 at 15 MV and 7 at 6 MV. The computed mean with a

cutoff of 1500 MU/cGy was 36.52 and 9.17 with a standard deviation 77.39 and 7.71 for

RSN 4 and 7 respectively. For RSN 4 these numbers are representative of only three

patients, so the numbers are easily skewed, and for RSN 7 the IMRT data was for a single

10

head and neck patient. Two of the three patients for RSN 4 are eight field head and neck

patients. The last is an eight field plan with an unrecorded reference point. All contain

split fields. Since the dose calculation point is taken from isocenter, if isocenter is

blocked off by MLCs then the dose becomes very small, making the MU/cGy become

extremely high and really meaningless. In this case it causes RSN 7 to have an outlier at

25.81, which has a dose which is an order of magnitude less than any other field, when all

the rest of the field doses are below 10. Using the cutoff of 25 MU/cGy the mean and

standard deviation become more acceptable values of 5.85 and 2.29. As for RSN 4, its

values range from 46.15 to a little over 323 MU/cGy. If the data is analyzed for

treatments of less than 46 MU/cGy then the mean becomes 3.14 and the standard

deviation 1.10. In both cases the numbers are now well within the NCRP recommended

value range.

HSN 3, another hospital center, RSN 5 at 6 MV (Table 2.8) has a mean and

standard deviation of 7.36 and 6.72. This number is a decent value since the IMRT

treatments performed on the machine are primarily head and necks which call for many

small fields with more MU/cGy. As mentioned in the introduction MUconv is usually

defined to be 1 MU/cGy, this creates a conservative value for CI, however, vaults are

currently shielded for a conventional MU/cGy which exceeds this number due to

differing techniques and wedge use. It is then practical, to examine higher MUIMRT in

this light. Therefore, when the value of the MUIMRT mean is divided by the mean of the

machine’s conventional treatments (Table 2.46) the CI becomes 4.74.

11

HSN 6, a stand alone cancer center, RSN 2 at 6 MV (Table 2.12) has a mean and

standard deviation of 6.29 and 7.12. Just like the previous machine if the MUIMRT mean

is divided by the conventional mean, the CI become 5.11, but also like HSN 2 it contains

a few fields which contain doses of an order of magnitude less than other fields in a

patient’s treatment. If these fields are thrown out then a cutoff of 25 MU/cGy may be

used to yield a mean and standard deviation of 5.04 and 3.25.

HSN 8, a hospital center, RSN 1 (Table 2.14) has a mean and standard deviation

of 8.33 and 17.96 and RSN 2 has 10.15 and 18.85, both at 6 MV. When fields are

removed that again are less in dose by an order of magnitude than other fields in a patient

treatment then values of MU/cGy between 55 and 440 drop out and the 25 MU/cGy

cutoff may be used, which brings the mean and standard deviation down to 7.15 and 2.80

for RSN 1 and 7.35 and 2.96 for RSN 2.

Table 2.17 for HSN 10, a hospital center, RSN 3 shows its 6 MV mode has a

mean and standard deviation of 11.52 and 7.62 and its 15 MV mode has 14.14 and 8.34.

The field doses are uniform throughout and there is no reason to use a cutoff. Head and

necks and brains are treated with 6MVs driving up the MU/cGy. When both treatment

modes are compared to the conventional means, then the CI drops to 5.35 for 6MV and

9.48 for 15MV. The 15 MV is still a little high in comparison to the NCRP

recommended value.

A lower cutoff may be used for HSN 12, a hospital center, RSN 1 (Table 2.19) at

6 MV which has a mean and standard deviation of 5.87 and 6.85. When values that are

derived from field doses that are an order of magnitude less than the other field doses in a

12

patient treatment, then the 25 MU/cGy cutoff may be used and the mean and standard

deviation becomes 4.93 and 2.88.

For HSN 13, a hospital cancer center, RSN 1 (Table 2.21) in 6MV mode some

MU/cGy are almost as high as 800 MU/cGy due to the low doses assigned to fields where

the isocenter is blocked. If these high values are disallowed then the 50 MU/cGy cutoff

may be used which brings the mean to 10.76. When divided by the conventional mean

the CI becomes 6.15. Its 18MV treatment mode has a mean and standard deviation of

7.37 and 6.91. Since 2% of the treatments are above 25 MU/cGy and these are split

fields around critical structures, i.e., with blocked isocenter, a cutoff of 25 MU/cGy may

be used for the 18 MV mode. This brings the mean and standard deviation down to 6.49

and 3.40.

HSN 15, a university hospital center, RSN 3 (Table 2.24) at 4 MV has a mean and

standard deviation of 8.01 and 2.89. Again, when divided by the conventional mean, the

CI drops to 4.67.

When the 600 MU/cGy IMRT setup fields are removed from HSN 16, a

university hospital center, RSN 3 (Table 2.28) at 6MV, the mean and standard deviation

fall from 4.25 and 13.26 to 3.96 and 1.48. This is the same for HSN 17, another

university hospital center, RSN 4 (Table 2.31) at 6 MV which sees its mean and standard

deviation drop from 6.44 and 32.48 to 6.43 and 3.05 when the setup fields that are greater

than 50 MU/cGy are removed.

Unrestricted values for IMRT MU/cGy means can be seen in tables 2.46 to 2.51

of the appendix for different photon energies. For these tables the IMRT MU/cGy is a

13

simple mean. The value, C, is the MU/cGy factor for conventional treatments, which do

not include any IMRT or TBI treatments, but does include wedges. The value C differs

from MUconv in that C is a mean of all conventional treatments, and MUconv is defined as

the MU required to deliver the same dose as MUIMRT to a phantom at a 10 cm depth at

100 source-to-axis distance with a 10cm by 10cm field (6). FI is the fraction of

treatments that are IMRT.

A conservative value of the IMRT factor can be ascertained by simply using the

IMRT MU/cGy. To get a number that more closely resembles the reality of clinical

operation, the IMRT MU/cGy can be divided by conventional MU/cGy (C). When tables

2.46 and 2.47 are examined, it can be seen that three out of 44 machines using low energy

photons have an IMRT MU/cGy value that is above the conservative CI of 2 to 10. When

the IMRT MU/cGy is divided by the conventional MU/cGy this falls to one out of 44. In

four cases the IMRT MU/cGy is lower than the conventional MU/cGy.

For machines performing IMRT at energies greater than 6 MV, only two out of 24

had a value greater than 10 MU/cGy. When IMRT MU/cGy was divided by the

conventional MU/cGy, one outlier disappeared and the other will disappear when a cutoff

is used. The tables were also recreated for only IMRT MU/cGy using cutoffs and can be

seen in the appendix in Tables 2.52 to Table 2.57.

TBI has been presented the same as IMRT. Even with the volume of fields in this

study. There were only a total of nine patients divided between four centers using four

treatment machines and three different energies. This makes it difficult to draw any

14

definitive numbers for a TBI Workload. The treatments may be seen table 2.58 in the

appendix.

15

CHAPTER III: DISCUSSION AND CONCLUSION

The NCRP estimate for the IMRT factor of 2-10 is sufficient, based on the data

from the reporting centers. These results were independent of energy. For low energy

beams, 4 or 6 MV, there were only three deviations from the range suggested in NCRP

151 for 44 different machines. For high energy beam, 10 MV or greater, there were two

values of CI above the NCRP range for 24 machines.

All of the above mentioned deviations disappear when a reasonable cutoff is

applied or the IMRT MU/cGy is divided by the conventional MU/cGy. Also, the

deviations were almost exclusively from head and neck treatments which usually contain

many small fields which cause IMRT treatments to have a larger amount of monitor units

per centigray.

If we look first strictly at only removing outliers at a reasonable cutoff, the only

outliers that remain with a combined mean plus one standard deviation over 10 are seen

in table 3.1. The cutoffs were established by either removing extraneous high numbers

caused either by the insertion of IMRT set-up fields or by removing fields with

uncharacteristically low dose. The low dose numbers are caused by isocenter being

blocked for the majority of the segments delivered in the treatment field.

HSN RSN Energy Mean Standard Deviation

3 5 6X 7.36 6.72

8 2 6X 7.35 2.96

10 3 6X 11.52 7.62

10 3 15X 14.14 8.34

13 1 6X 10.76 9.99

15 3 4X 8.01 2.89

20 2 6X 8.57 1.87

Table 3.1. Mean and standard deviations above NCRP suggested range after cutoff.

16

If we take these remaining deviations and divide their means by their respective

conventional mean, then we see that all of the outliers now disappear. Although using a

strict IMRT mean gives a more conservative answer, dividing the IMRT mean by the

conventional mean yields a number that is closer to reality, since secondary shielding in

vaults are already designed to handle this conventional workload. The results of

performing this operation can be seen in table 3.2. Only HSN 10, RSN 3 still hovers near

10. This machine represents 526 of 34,059 or 1.5% of IMRT treatments at 15 MV.

HSN RSN Energy IMRT Mean Conventional Mean IMRT/Conventional

3 5 6X 7.36 1.55 4.75

8 2 6X 7.35 1.20 6.13

10 3 6X 11.52 2.15 5.36

10 3 15X 14.14 1.49 9.49

13 1 6X 10.76 1.75 6.15

15 3 4X 8.01 1.72 4.66

20 2 6X 8.57 1.68 5.10

Table 3.2. IMRT mean divided by Conventional mean.

A chart of the mean values of CI for each MV, in the above table, gives:

CI

0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20 25

MV

CI

IMRT/C

Linear (IMRT/C)

Figure 3.1. Mean values of CI for each MV.

17

If charts are created for all IMRT machines the trend appears first without a cutoff as:

Total IMRT Treatments without Cutoff

0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20 25

MV

CI

Total IMRT Treatments without

Cutoff

Linear (Total IMRT Treatments

without Cutoff)

Figure 3.2. Mean values of CI for each MV for total treatments without cutoff.

Energy Sample Size Mean Standard Deviation

4 1 8.01 0.00

6 43 5.44 3.07

15 15 7.04 8.56

16 2 3.85 0.06

18 6 3.77 2.03

20 1 3.59 0.00

Low Energy 44 5.50 3.06

High Energy 24 5.81 6.96

Table 3.3. IMRT mean and standard deviation for total treatments without cutoff.

Low energy is defined as 4 or 6 MV x-rays and high energy treatments are any treatments

above 10 MV.

Next the trend is plotted with the cutoffs discussed in section two:

18

Total IMRT Treatments

0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20 25

MV

CI

Total

Linear (Total)

Figure 3.3. Mean values of CI for each MV for total treatments with cutoff.


4 1 8.01 0.00

6 43 5.02 2.14

15 15 4.81 2.75

16 2 3.85 0.06

18 6 3.62 1.72

20 1 3.59 0.00

Low Energy 44 5.09 2.16


Table 3.4. IMRT mean and standard deviation for total treatments with cutoff.

It is interesting to note that with or without a cutoff both low and high energy means are

very similar. The low energy mean is 5.50 with a standard deviation of 3.06 without a

cutoff and 5.09 and 2.16 with a cutoff. The high energy mean and standard deviation

without a cutoff are greatly affected by the 36.52 MU/cGy outlier. Without a cutoff the

19

high energy mean and standard deviation are 5.81 and 6.96, with a cutoff they are 4.38

and 2.36.

The remainder of the plots uses the data with the cutoffs. The next couple is for

mono and dual energy machines. A mono energy machine is defined as a machine that is

used for only one photon energy. Likewise, a dual energy machine uses two photon

energies.

Mono Energy Machines

0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20 25

MV

CI

Mono Energy Machines

Linear (Mono Energy Machines)

Figure 3.4. Mean values of CI for each MV for mono energy machines.


4 1 8.01 0

6 4 4.885 1.824582144

15 1 5.23 0

16 0 0 0

18 0 0 0

20 0 0 0

Low Energy 5 5.51 5.92


Table 3.5. IMRT mean and standard deviation for mono energy machines.

20

Dual Energy Machines

0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20 25

MV

CI

Dual Energy Machines

Linear (Dual Energy Machines)

Figure 3.5. Mean values of CI for each MV for dual energy machines.


4 0 0.00 0.00

6 39 5.04 2.19

15 14 4.78 2.86

16 2 3.85 0.06

18 6 3.62 1.72

20 1 3.59 0.00

Low Energy 39 5.04 2.19


Table 3.6. IMRT mean and standard deviation for dual energy machines.

With a small sample for mono energy machines, five low energy machines and one high

energy machine the numbers are easily skewed, and are very similar to the numbers

without a cutoff. The dual energy machine results are very close to the mean and

standard deviation of the total with cutoff.

21

The next pair is for mono and dual use machines. Use refers to how the machine

treats IMRT. A mono use machine only uses one energy for IMRT, and a dual use

machine treats IMRT patients at both of its photon energies.

Mono Use Machines

0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20 25

MV

CI

Mono Use Machines

Linear (Mono Use Machines)

Figure 3.6. Mean values of CI for each MV for mono use machines.


4 1 8.01 0.00

6 23 5.11 1.25

15 1 5.23 0.00

16 1 3.80 0.00

18 1 3.37 0.00

20 0 0.00 0.00

Low Energy 24 5.24 2.65


Table 3.7. IMRT mean and standard deviation for mono use machines.

22

Dual Use Machines

0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20 25

MV

CI

Dual Use Machines

Linear (Dual Use Machines)

Figure 3.7. Mean values of CI for each MV for dual use machines.


4 0 0.00 0.00

6 20 4.92 2.88

15 14 4.78 2.86

16 1 3.89 0.00

18 5 3.67 1.92

20 1 3.59 0.00

Low Energy 20 4.92 2.88


Table 3.8. IMRT mean and standard deviation for dual use machines.

In this case the low energy sample was almost evenly split with 24 mono use and 20 dual

use and it can be seen that their numbers are very close and well within a standard

deviation of the total. The high energy sample has only three for mono energy and 21 for

dual energy, yet the results are still within a standard deviation of the total.

23

The next two plots divide the data between large and small facilities. A small

facility is defined as only having one or two machines. A large facility has three or more

and would thus require a larger staff with more than a single doctor.

Large Facilities

0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20 25

MV

CI

Large Facilities

Linear (Large Facilities)

Figure 3.8. Mean values of CI for each MV for large facilities.


4 1 8.01 0.00

6 34 4.80 1.49

15 14 4.81 2.86

16 2 3.85 0.06

18 3 3.82 0.42

20 1 3.59 0.00

Low Energy 35 4.90 2.10


Table 3.9. IMRT mean and standard deviation for large facilities.

24

Small Facilities

0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20 25

MV

CI

Small Facilities

Linear (Small Facilities)

Figure 3.9. Mean values of CI for each MV for small facilities.


4 0 0.00 0.00

6 9 5.85 2.55

15 1 4.82 0.00

16 0 0.00 0.00

18 3 3.43 2.67

20 0 0.00 0.00

Low Energy 9 5.85 2.55


Table 3.10. IMRT mean and standard deviation for small facilities.

The large facility sample group is much larger than the small facility group, with 35 low

energy and 20 high energy samples. The small facility group has 9 low energy and 4

high energy samples.

The trend of interest is that in all cases, besides the group computed without a

cutoff where a single point was greatly skewing the results, is that the numbers are

25

consistently lower, in MU/cGy, for high energy treatments, but still close (within a

standard deviation). Also there is no significant difference for machine type or use or

facility size. For low energy calculations for WL a CI of 5.1 may be used, this number

may be increased by its standard deviation if the facility engages in procedures such as

head and necks which use many more MU/cGy than other procedures. For high energy

calculations of WL a CI of 4.4 may be used. Again this number may be increased if a

machine is specialized in procedures that use more MU/cGy. It is interesting to note that

in both cases the mean plus two standard deviations for the calculated value of the CI, are

less than the maximum value of ten for the range discussed in NCRP Report 151.

The low amount of TBI treatments, a total of nine patients for 184 out of 374,003

total exposures, makes any conclusions drawn tenuous at best. In all cases the workload

in MU/cGy was much higher than conventional treatments, as would be expected. For 6

and 15 MV treatments the mean MU/cGy hovered around 20, and for 18 MV TBI

treatments the number increased to a little over 30.

In conclusion, although the numbers are too scant to make any statements about

the contribution TBI makes to workload, there is more than enough data to estimate the

IMRT contribution to leakage workload. An IMRT factor, CI, of 5.1 may be used for low

energy photon calculations, and a CI of 4.4 may be used for high energy photon

calculations. These numbers are higher than the studies of Followill and Mechalakos, but

except in the case of low energy IMRT for Mechalakos are within a standard deviation.

26

APPENDIX: FIGURES AND TABLES FROM RESULTS

HSN RSN MV of IMRT Table Number page

1 1 6 and 18 2.2 29

1 2 6 2.3 31

2 4 15 2.4 33

2 7 6 and 15 2.5 35

3 2 6 2.6 37

3 4 6 2.7 39

3 5 6 2.8 41

3 6 6 2.9 43

5 2 6 and 18 2.10 45

5 3 6 and 20 2.11 47

6 2 6 2.12 49

7 1 6 and 15 2.13 51

8 1 6 2.14 53

8 2 6 2.14 53

9 1 6 2.15 55

10 2 15 2.16 57

10 3 6 and 15 2.17 59

11 1 6 and 18 2.18 61

12 1 6 2.19 63

12 2 6 and 18 2.20 65

13 1 6 and 18 2.21 67

14 1 6 2.22 69

15 2 6 and 15 2.23 71

15 3 4 2.24 73

15 4 6 and 15 2.25 75

16 1 6 2.26 77

16 2 6 2.27 79

16 3 6 2.28 81

17 1 6 2.29 83

17 2 6 2.30 85

17 4 6 2.31 87

17 5 6 2.32 89

17 6 6 2.32 91

17 7 6 2.32 91

17 8 6 2.32 91

27

18 1 6 2.33 91

18 2 6 and 15 2.34 93

18 3 6 and 15 2.35 95

18 4 6 and 15 2.36 97

18 5 6 and 15 2.37 99

18 6 6 2.38 101

19 1 6 and 15 2.39 103

19 2 6 and 15 2.40 105

20 1 16 2.41 107

20 2 6 and 16 2.42 109

21 1 18 2.43 111

22 1 6 and 15 2.44 113

22 2 6 and 15 2.45 115

Table 2.1. Page location of machines by HSN, RSN, and MV combination.

28

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

0 2 4 6 8 10 12

MU/cGy

N

RSN 1 6X IMRT

RSN 1 6X

RSN 1 18X IMRT

RSN 1 18X

RSN 1 All IMRT

RSN 1 All Energies

Figure 2.1. HSN 1, RSN 1 Frequency distribution of MU/cGy, plotted versus bin mid-

point value. The different x-ray beams and combinations are indicated on the graph.

29

RSN 1 6X IMRT

RSN 1 6X

RSN 1 18X IMRT

RSN 1 18X

RSN 1 All IMRT

RSN 1 All Energies

mean(0-15)= 4.23 2.66 1.58 1.35 4.08 2.18

mean(0-25)= 4.23 2.66 1.58 1.35 4.08 2.18

mean(0-50)= 4.94 2.97 1.58 1.35 4.76 2.38

mean(0-200)= 4.94 2.97 1.58 1.35 4.76 2.38

mean(0-1500)= 4.94 2.97 1.58 1.35 4.76 2.38

stdev(0-15)= 2.33 1.98 0.24 0.28 2.34 1.71

stdev(0-25)= 2.33 1.98 0.24 0.28 2.34 1.71

stdev(0-50)= 4.76 3.47 0.24 0.28 4.69 2.88

stdev(0-200)= 4.76 3.47 0.24 0.28 4.69 2.88

stdev(0-1500)= 4.76 3.47 0.24 0.28 4.69 2.88

Table 2.2. HSN 1, RSN 1 mean and standard deviation at different cutoffs of MU/cGy.

30

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

0 5 10 15 20

MU/cGy

N

RSN 2 6X IMRT

RSN 2 6X



31

RSN 2 6X IMRT RSN 2 6X

mean(0-15)= 3.17 2.06

mean(0-25)= 4.95 2.58

mean(0-50)= 4.95 2.58

mean(0-200)= 4.95 2.58

mean(0-1500)= 4.95 2.58

stdev(0-15)= 0.77 0.93

stdev(0-25)= 5.11 3.10

stdev(0-50)= 5.11 3.10

stdev(0-200)= 5.11 3.10

stdev(0-1500)= 5.11 3.10


32

0.0

10.0

20.0

30.0

40.0

50.0

60.0

0 2 4 6 8 10

MU/cGy

N

RSN 4 15X IMRT

RSN 4 15X



33


mean(0-15)= 3.14 1.72

mean(0-25)= 3.14 1.72

mean(0-50)= 5.63 2.20

mean(0-200)= 17.68 4.83

mean(0-1500)= 36.52 9.24

stdev(0-15)= 1.10 0.85

stdev(0-25)= 1.10 0.85

stdev(0-50)= 10.11 4.66

stdev(0-200)= 31.11 15.73

stdev(0-1500)= 77.39 38.58


34

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

0 2 4 6 8 10

MU/cGy

N

RSN 7 6X IMRT

RSN 7 6X

RSN 7 15X IMRT

RSN 7 15X

RSN 7 All IMRT

RSN 7 All Energies



35

RSN 7 6X IMRT

RSN 7 6X

RSN 7 15X IMRT

RSN 7 15X

RSN 7 All IMRT

RSN 7 All Energies

mean(0-15)= 5.85 1.89 3.00 1.53 5.04 1.67

mean(0-25)= 5.85 1.89 3.00 1.53 5.04 1.67

mean(0-50)= 9.17 2.46 3.00 1.53 7.63 1.91

mean(0-200)= 9.17 2.46 3.00 1.53 7.63 1.91

mean(0-1500)= 9.17 2.46 3.00 1.53 7.63 1.91

stdev(0-15)= 2.29 1.75 0.75 0.53 2.36 1.20

stdev(0-25)= 2.29 1.75 0.75 0.53 2.36 1.20

stdev(0-50)= 7.71 4.04 0.75 0.53 7.20 2.68

stdev(0-200)= 7.71 4.04 0.75 0.53 7.20 2.68

stdev(0-1500)= 7.71 4.04 0.75 0.53 7.20 2.68


36

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

0 2 4 6 8 10 12 14

MU/cGy

N

RSN 2 6X IMRT

RSN 2 6X



37


mean(0-15)= 4.88 4.61

mean(0-25)= 4.89 4.63

mean(0-50)= 4.89 4.63

mean(0-200)= 4.89 4.87

mean(0-1500)= 4.89 4.87

stdev(0-15)= 1.85 2.02

stdev(0-25)= 1.9 2.06

stdev(0-50)= 1.9 2.06

stdev(0-200)= 1.9 5.7

stdev(0-1500)= 1.9 5.7


38

0.0

5.0

10.0

15.0

20.0

25.0

30.0

0 2 4 6 8 10 12 14

MU/cGy

N

RSN 4 6X IMRT

RSN 4 6X



39


mean(0-15)= 4.54 2.77

mean(0-25)= 4.54 2.77

mean(0-50)= 4.54 2.77

mean(0-200)= 4.54 2.77

mean(0-1500)= 4.54 2.77

stdev(0-15)= 1.18 1.65

stdev(0-25)= 1.18 1.65

stdev(0-50)= 1.18 1.65

stdev(0-200)= 1.18 1.65

stdev(0-1500)= 1.18 1.65


40

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

0 2 4 6 8 10 12 14

MU/cGy

N

RSN 5 6X IMRT

RSN 5 6X



41


mean(0-15)= 5.78 4.49

mean(0-25)= 6.04 4.69

mean(0-50)= 7.36 5.67

mean(0-200)= 7.36 5.67

mean(0-1500)= 7.36 5.67

stdev(0-15)= 3.00 3.18

stdev(0-25)= 3.69 3.72

stdev(0-50)= 6.72 6.25

stdev(0-200)= 6.72 6.25

stdev(0-1500)= 6.72 6.25


42

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

0 2 4 6 8 10 12 14

MU/cGy

N

RSN 6 6X IMRT

RSN 6 6X



43


mean(0-15)= 4.53 2.76

mean(0-25)= 4.53 2.76

mean(0-50)= 4.53 2.76

mean(0-200)= 4.53 4.75

mean(0-1500)= 4.53 4.75

stdev(0-15)= 1.43 1.52

stdev(0-25)= 1.43 1.52

stdev(0-50)= 1.43 1.52

stdev(0-200)= 1.43 16.19

stdev(0-1500)= 1.43 16.19


44

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

0 1 2 3 4 5 6 7

MU/cGy

N

RSN 2 6X IMRT

RSN 2 6X

RSN 2 18X IMRT

RSN 2 18X

RSN 2 All IMRT

RSN 2 All Energies



45

RSN 2 6X IMRT

RSN 2 6X

RSN 2 18X IMRT

RSN 2 18X

RSN 2 All IMRT

RSN 2 All Energies

mean(0-15)= 3.19 1.44 3.87 3.20 3.86 2.73

mean(0-25)= 3.19 1.44 3.87 3.20 3.86 2.73

mean(0-50)= 3.19 1.44 3.87 3.20 3.86 2.73

mean(0-200)= 3.19 27.81 3.87 13.83 3.86 17.86

mean(0-1500)= 3.19 27.81 3.87 13.83 3.86 17.86

stdev(0-15)= 0.77 0.47 1.82 1.95 1.81 1.86

stdev(0-25)= 0.77 0.47 1.82 1.95 1.81 1.86

stdev(0-50)= 0.77 0.47 1.82 1.95 1.81 1.86

stdev(0-200)= 0.77 55.99 1.82 37.75 1.81 44.25

stdev(0-1500)= 0.77 55.99 1.82 37.75 1.81 44.25


46

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

0 2 4 6 8

MU/cGy

N

RSN 3 6X IMRT

RSN 3 6X

RSN 3 20X IMRT

RSN 3 20X

RSN 3 All IMRT

RSN 3 All Energies



47

RSN 3 6X IMRT

RSN 3 6X

RSN 3 20X IMRT

RSN 3 20X

RSN 3 All IMRT

RSN 3 All Energies

mean(0-15)= 3.55 1.58 3.59 2.95 3.59 2.52

mean(0-25)= 3.55 1.58 3.59 2.95 3.59 2.52

mean(0-50)= 3.55 1.58 3.59 2.95 3.59 2.52

mean(0-200)= 3.55 25.65 3.59 13.72 3.59 17.67

mean(0-1500)= 3.55 25.65 3.59 13.72 3.59 17.67

stdev(0-15)= 0.40 0.62 0.99 1.39 0.97 1.36

stdev(0-25)= 0.40 0.62 0.99 1.39 0.97 1.36

stdev(0-50)= 0.40 0.62 0.99 1.39 0.97 1.36

stdev(0-200)= 0.40 54.23 0.99 37.98 0.97 44.40

stdev(0-1500)= 0.40 54.23 0.99 37.98 0.97 44.40


48

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

0 10 20 30 40 50

MU/cGy

N

RSN 2 6X IMRT

RSN 2 6X



49


mean(0-15)= 4.64 4.45

mean(0-25)= 5.04 4.85

mean(0-50)= 6.29 6.03

mean(0-200)= 6.29 6.03

mean(0-1500)= 6.29 6.03

stdev(0-15)= 2.27 2.34

stdev(0-25)= 3.25 3.28

stdev(0-50)= 7.12 7.03

stdev(0-200)= 7.12 7.03

stdev(0-1500)= 7.12 7.03


50

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

0 2 4 6 8 10 12 14

MU/cGy

N

RSN 1 6X IMRT

RSN 1 6X

RSN 1 15X IMRT

RSN 1 15X

RSN 1 All IMRT

RSN 1 All Energies



51

RSN 1 6X IMRT

RSN 1 6X

RSN 1 15X IMRT

RSN 1 15X

RSN 1 All IMRT

RSN 1 All Energies

mean(0-15)= 6.51 4.21 4.77 4.07 5.28 4.12

mean(0-25)= 6.73 4.37 4.82 4.11 5.39 4.21

mean(0-50)= 6.77 4.39 4.82 4.15 5.40 4.24

mean(0-200)= 6.77 4.39 4.82 4.47 5.40 4.44

mean(0-1500)= 6.77 4.39 4.82 191.22 5.40 126.72

stdev(0-15)= 2.26 2.99 2.64 2.74 2.65 2.84

stdev(0-25)= 2.74 3.31 2.74 2.83 2.88 3.03

stdev(0-50)= 2.87 3.38 2.74 3.08 2.92 3.20

stdev(0-200)= 2.87 3.38 2.74 5.79 2.92 5.01

stdev(0-1500)= 2.87 3.38 2.74 623.21 2.92 512.06


52

0.0

2.0

4.0

6.0

8.0

10.0

12.0

0 5 10 15 20

MU/cGy

N

RSN 1 6X IMRT

RSN 1 6X

RSN 2 6X IMRT

RSN 2 6X

Figure 2.13. HSN 8, RSN 1 and 2 Frequency distribution of MU/cGy, plotted versus bin

mid-point value. The different x-ray beams and combinations are indicated on the graph.

53

RSN 1 6X IMRT

RSN 1 6X

RSN 2 6X IMRT

RSN 2 6X

mean(0-15)= 6.95 6.40 7.15 6.57

mean(0-25)= 7.15 6.58 7.35 6.76

mean(0-50)= 7.22 6.65 7.82 7.19

mean(0-200)= 7.39 6.81 9.87 9.05

mean(0-1500)= 8.33 7.66 10.15 9.31

stdev(0-15)= 2.34 2.79 2.51 2.97

stdev(0-25)= 2.80 3.18 2.96 3.34

stdev(0-50)= 3.12 3.44 4.89 5.04

stdev(0-200)= 5.02 5.11 17.19 16.55

stdev(0-1500)= 17.96 17.22 18.85 18.13

Table 2.14. HSN 8, RSN 1 and 2 mean and standard deviation at different cutoffs of

MU/cGy.

54

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

0 2 4 6 8 10

MU/cGy

N

RSN 1 6X IMRT

RSN 1 6X



55


mean(0-15)= 3.86 2.61

mean(0-25)= 3.86 2.61

mean(0-50)= 3.86 2.61

mean(0-200)= 3.86 2.61

mean(0-1500)= 3.86 2.61

stdev(0-15)= 1.57 1.60

stdev(0-25)= 1.57 1.60

stdev(0-50)= 1.57 1.60

stdev(0-200)= 1.57 1.60

stdev(0-1500)= 1.57 1.60


56

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

0 5 10 15 20

MU/cGy

N

RSN 2 15X IMRT

RSN 2 15X



57


mean(0-15)= 5.23 5.23

mean(0-25)= 5.23 5.23

mean(0-50)= 5.23 5.23

mean(0-200)= 5.23 5.23

mean(0-1500)= 5.23 5.23

stdev(0-15)= 1.78 1.78

stdev(0-25)= 1.78 1.78

stdev(0-50)= 1.78 1.78

stdev(0-200)= 1.78 1.78

stdev(0-1500)= 1.78 1.78


58

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

0 5 10 15 20 25 30 35 40

MU/cGy

N

RSN 3 6X IMRT

RSN 3 6X

RSN 3 15X IMRT

RSN 3 All IMRT

RSN 3 All Energies

RSN 3 15X



59

RSN 3 6X IMRT

RSN 3 6X

RSN 3 15X IMRT

RSN 3 15X

RSN 3 All IMRT

RSN 3 All Energies

mean(0-15)= 7.82 5.22 10.69 5.62 8.82 5.38

mean(0-25)= 10.91 7.66 11.37 6.15 11.04 7.11

mean(0-50)= 11.52 8.18 14.14 7.95 12.37 8.10

mean(0-200)= 11.52 8.18 14.14 7.95 12.37 8.10

mean(0-1500)= 11.52 8.18 14.14 7.95 12.37 8.10

stdev(0-15)= 3.26 3.81 2.45 4.86 3.30 4.26

stdev(0-25)= 6.58 6.78 3.30 5.44 5.65 6.30

stdev(0-50)= 7.62 7.76 8.34 8.65 7.92 8.09

stdev(0-200)= 7.62 7.76 8.34 8.65 7.92 8.09

stdev(0-1500)= 7.62 7.76 8.34 8.65 7.92 8.09


60

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

0 2 4 6 8 10 12 14

MU/cGy

N

RSN 1 6X IMRT

RSN 1 6X

RSN 1 18X IMRT

RSN 1 18X

RSN 1 All IMRT

RSN 1 All Energies



61


RSN 1 6X IMRT

RSN 1 6X

RSN 1 18X IMRT

RSN 1 18X

RSN 1 All IMRT

RSN 1 All Energies

mean(0-15)= 1.70 1.90 2.22 1.68 2.14 1.79

mean(0-25)= 1.70 1.90 2.22 1.68 2.14 1.79

mean(0-50)= 1.70 1.90 2.22 1.68 2.14 1.79

mean(0-200)= 1.70 1.90 2.22 17.93 2.14 10.49

mean(0-1500)= 1.70 1.90 2.22 17.93 2.14 10.49

stdev(0-15)= 0.56 0.65 1.19 1.38 1.13 1.09

stdev(0-25)= 0.56 0.65 1.19 1.38 1.13 1.09

stdev(0-50)= 0.56 0.65 1.19 1.38 1.13 1.09

stdev(0-200)= 0.56 0.65 1.19 45.91 1.13 34.56

stdev(0-1500)= 0.56 0.65 1.19 45.91 1.13 34.56

62

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

0 2 4 6 8 10

MU/cGy

N

RSN 1 6X IMRT

RSN 1 6X



63


mean(0-15)= 4.72 2.23

mean(0-25)= 4.93 2.29

mean(0-50)= 5.41 2.41

mean(0-200)= 5.87 2.48

mean(0-1500)= 5.87 2.48

stdev(0-15)= 2.15 1.49

stdev(0-25)= 2.88 1.81

stdev(0-50)= 4.66 2.67

stdev(0-200)= 6.85 3.30

stdev(0-1500)= 6.85 3.30


64

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

0 2 4 6 8 10

MU/cGy

N

RSN 2 6X IMRT

RSN 2 6X

RSN 2 18X IMRT

RSN 2 18X

RSN 2 All IMRT

RSN 2 All Energies



65


RSN 2 6X IMRT

RSN 2 6X

RSN 2 18X IMRT

RSN 2 18X

RSN 2 All IMRT

RSN 2 All Energies

mean(0-15)= 4.90 2.02 3.87 2.65 3.88 2.58

mean(0-25)= 4.90 2.02 4.00 2.73 4.01 2.66

mean(0-50)= 4.90 2.08 4.21 2.85 4.22 2.77

mean(0-200)= 4.90 2.08 4.21 2.85 4.22 2.77

mean(0-1500)= 4.90 2.08 4.21 2.85 4.22 2.77

stdev(0-15)= 1.18 1.24 2.10 2.05 2.10 1.99

stdev(0-25)= 1.18 1.24 2.56 2.36 2.55 2.28

stdev(0-50)= 1.18 2.02 3.46 2.97 3.44 2.90

stdev(0-200)= 1.18 2.02 3.46 2.97 3.44 2.90

stdev(0-1500)= 1.18 2.02 3.46 2.97 3.44 2.90

66

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

0 5 10 15 20 25

MU/cGy

N

RSN 1 6X IMRT

RSN 1 6X

RSN 1 18X IMRT

RSN 1 18X

RSN 1 All IMRT

RSN 1 All Energies



67


RSN 1 6X IMRT

RSN 1 6X

RSN 1 18X IMRT

RSN 1 18X

RSN 1 All IMRT

RSN 1 All Energies

mean(0-15)= 6.37 5.56 6.00 3.81 6.22 4.63

mean(0-25)= 8.21 7.22 6.49 4.23 7.59 5.70

mean(0-50)= 10.76 9.48 7.10 4.76 9.49 7.16

mean(0-200)= 13.60 11.97 7.37 4.89 11.48 8.53

mean(0-1500)= 19.08 16.72 7.37 4.89 15.14 11.01

stdev(0-15)= 3.38 3.57 2.37 2.97 3.03 3.38

stdev(0-25)= 5.54 5.62 3.40 3.84 4.94 5.03

stdev(0-50)= 9.99 9.78 6.00 5.98 8.99 8.47

stdev(0-200)= 19.81 18.85 6.91 6.47 16.85 14.69

stdev(0-1500)= 60.42 56.46 6.91 6.47 49.67 41.28

68

0.0

10.0

20.0

30.0

40.0

50.0

60.0

0 5 10 15 20 25

MU/cGy

N

RSN 1 6X IMRT

RSN 1 6X



69


mean(0-15)= 3.70 2.19

mean(0-25)= 3.95 3.06

mean(0-50)= 3.95 3.06

mean(0-200)= 3.95 3.06

mean(0-1500)= 3.95 3.06

stdev(0-15)= 1.36 1.45

stdev(0-25)= 2.46 4.11

stdev(0-50)= 2.46 4.11

stdev(0-200)= 2.46 4.11

stdev(0-1500)= 2.46 4.11


70

0.0

10.0

20.0

30.0

40.0

50.0

60.0

0 2 4 6 8 10

MU/cGy

N

RSN 2 6X IMRT

RSN 2 6X

RSN 2 15X IMRT

RSN 2 15X

RSN 2 All IMRT

RSN 2 All Energies



71


RSN 2 6X IMRT

RSN 2 6X

RSN 2 15X IMRT

RSN 2 15X

RSN 2 All IMRT

RSN 2 All Energies

mean(0-15)= 5.66 2.86 4.40 3.57 4.53 3.43

mean(0-25)= 5.66 2.86 4.40 3.57 4.53 3.43

mean(0-50)= 5.66 2.86 4.40 3.57 4.53 3.43

mean(0-200)= 5.66 2.86 4.40 3.57 4.53 3.43

mean(0-1500)= 5.66 2.86 4.40 3.57 4.53 3.43

stdev(0-15)= 1.08 2.12 1.79 2.06 1.78 2.10

stdev(0-25)= 1.08 2.12 1.79 2.06 1.78 2.10

stdev(0-50)= 1.08 2.12 1.79 2.06 1.78 2.10

stdev(0-200)= 1.08 2.12 1.79 2.06 1.78 2.10

stdev(0-1500)= 1.08 2.12 1.79 2.06 1.78 2.10

72

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

0 5 10 15 20

MU/cGy

N

RSN 3 4X IMRT

RSN 3 4X



73


mean(0-15)= 7.91 3.97

mean(0-25)= 8.01 4.09

mean(0-50)= 8.01 4.09

mean(0-200)= 8.01 4.09

mean(0-1500)= 8.01 4.09

stdev(0-15)= 2.76 3.53

stdev(0-25)= 2.89 3.72

stdev(0-50)= 2.89 3.72

stdev(0-200)= 2.89 3.72

stdev(0-1500)= 2.89 3.72


74

0.0

10.0

20.0

30.0

40.0

50.0

60.0

0 2 4 6 8 10 12 14

MU/cGy

N

RSN 4 6X IMRT

RSN 4 6X

RSN 4 15X IMRT

RSN 4 15X

RSN 4 All IMRT

RSN 4 All Energies



75


RSN 4 6X IMRT

RSN 4 6X

RSN 4 15X IMRT

RSN 4 15X

RSN 4 All IMRT

RSN 4 All Energies

mean(0-15)= 6.57 2.64 6.67 4.22 6.66 3.80

mean(0-25)= 6.57 2.64 6.67 4.22 6.66 3.80

mean(0-50)= 6.57 2.64 6.67 4.22 6.66 3.80

mean(0-200)= 6.57 2.64 6.67 4.22 6.66 3.80

mean(0-1500)= 6.57 2.64 6.67 4.22 6.66 3.80

stdev(0-15)= 2.35 2.48 2.75 3.33 2.70 3.20

stdev(0-25)= 2.35 2.48 2.75 3.33 2.70 3.20

stdev(0-50)= 2.35 2.48 2.75 3.33 2.70 3.20

stdev(0-200)= 2.35 2.48 2.75 3.33 2.70 3.20

stdev(0-1500)= 2.35 2.48 2.75 3.33 2.70 3.20

76

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

0 2 4 6 8 10

MU/cGy

N

RSN 1 6X IMRT

RSN 1 6X



77


mean(0-15)= 3.82 3.28

mean(0-25)= 3.89 3.33

mean(0-50)= 3.96 3.39

mean(0-200)= 3.96 3.39

mean(0-1500)= 3.96 3.39

stdev(0-15)= 1.58 1.73

stdev(0-25)= 1.85 1.95

stdev(0-50)= 2.25 2.26

stdev(0-200)= 2.25 2.26

stdev(0-1500)= 2.25 2.26


78

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

0 2 4 6 8 10

MU/cGy

N

RSN 2 6X IMRT

RSN 2 6X



79


mean(0-15)= 3.81 3.20

mean(0-25)= 3.81 3.20

mean(0-50)= 3.81 3.20

mean(0-200)= 3.81 3.20

mean(0-1500)= 3.81 3.20

stdev(0-15)= 1.38 1.61

stdev(0-25)= 1.38 1.61

stdev(0-50)= 1.38 1.61

stdev(0-200)= 1.38 1.61

stdev(0-1500)= 1.38 1.61


80

0.0

5.0

10.0

15.0

20.0

25.0

30.0

0 2 4 6 8 10

MU/cGy

N

RSN 3 6X IMRT

RSN 3 6X



81


mean(0-15)= 3.96 2.92

mean(0-25)= 3.96 2.92

mean(0-50)= 3.96 2.92

mean(0-200)= 3.96 2.92

mean(0-1500)= 4.25 3.10

stdev(0-15)= 1.48 1.73

stdev(0-25)= 1.48 1.73

stdev(0-50)= 1.48 1.73

stdev(0-200)= 1.48 1.73

stdev(0-1500)= 13.26 10.38


82

0.0

5.0

10.0

15.0

20.0

25.0

0 2 4 6 8 10 12 14

MU/cGy

N

RSN 1 6X IMRT

RSN 1 6X



83


mean(0-15)= 4.79 3.35

mean(0-25)= 5.17 3.58

mean(0-50)= 5.44 3.74

mean(0-200)= 5.71 3.89

mean(0-1500)= 5.71 3.89

stdev(0-15)= 2.25 2.27

stdev(0-25)= 3.32 2.99

stdev(0-50)= 4.19 3.60

stdev(0-200)= 5.51 4.52

stdev(0-1500)= 5.51 4.52


84

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

0 2 4 6 8 10 12 14

MU/cGy

N

RSN 2 6X IMRT

RSN 2 6X



85


mean(0-15)= 7.08 6.01

mean(0-25)= 7.18 6.1

mean(0-50)= 7.25 6.16

mean(0-200)= 7.25 6.16

mean(0-1500)= 7.25 6.16

stdev(0-15)= 2.34 3.01

stdev(0-25)= 2.58 3.18

stdev(0-50)= 2.97 3.46

stdev(0-200)= 2.97 3.46

stdev(0-1500)= 2.97 3.46


86

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

0 5 10 15 20

MU/cGy

N

RSN 4 6X IMRT

RSN 4 6X



87


mean(0-15)= 6.32 4.21

mean(0-25)= 6.37 4.32

mean(0-50)= 6.43 4.39

mean(0-200)= 6.43 4.42

mean(0-1500)= 6.44 4.43

stdev(0-15)= 2.11 2.77

stdev(0-25)= 2.31 3.1

stdev(0-50)= 3.05 3.71

stdev(0-200)= 4.95 8.34

stdev(0-1500)= 32.48 24.18

Table 2.31. HSN 17, RSN 4 mean and standard deviation at different cutoffs of

MU/cGy.

88

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

0 5 10 15 20

MU/cGy

N

RSN 5 6X IMRT

RSN 6 6X IMRT

RSN 7 6X IMRT

RSN 8 6X IMRT

Figure 2.31. HSN 17, RSN 5, 6, 7, and 8 Frequency distribution of MU/cGy, plotted

versus bin mid-point value. The different x-ray beams and combinations are indicated on

the graph.

89

RSN 5 6X IMRT

RSN 6 6X IMRT

RSN 7 6X IMRT

RSN 8 6X IMRT

mean(0-15)= 4.54 5.44 5.27 5.26

mean(0-25)= 4.55 5.46 5.27 5.38

mean(0-50)= 4.60 5.46 5.27 5.38

mean(0-200)= 4.60 5.46 5.27 5.38

mean(0-1500)= 4.60 5.46 5.27 5.38

stdev(0-15)= 2.13 2.23 2.40 2.30

stdev(0-25)= 2.24 2.33 2.40 2.70

stdev(0-50)= 2.86 2.33 2.40 2.70

stdev(0-200)= 2.86 2.33 2.40 2.70

stdev(0-1500)= 2.86 2.33 2.40 2.70

Table 2.32. HSN 17, RSN 5, 6, 7, and 8 mean and standard deviation at different cutoffs

of MU/cGy.

90

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

0 2 4 6 8 10 12

MU/cGy

N

RSN 1 6X IMRT

RSN 1 6X



91


mean(0-15)= 4.21 3.83

mean(0-25)= 4.21 3.83

mean(0-50)= 4.21 3.83

mean(0-200)= 4.21 3.83

mean(0-1500)= 4.21 3.83

stdev(0-15)= 1.96 2.06

stdev(0-25)= 1.96 2.06

stdev(0-50)= 1.96 2.06

stdev(0-200)= 1.96 2.06

stdev(0-1500)= 1.96 2.06


92

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

0 3 6 9 12 15

MU/cGy

NRSN 2 6X IMRT

RSN 2 6X

RSN 2 15X IMRT

RSN 2 15X

RSN 2 All IMRT

RSN 2 All Energies



93

RSN 2 6X IMRT

RSN 2 6X

RSN 2 15X IMRT

RSN 2 15X

RSN 2 All IMRT

RSN 2 All Energies

mean(0-15)= 3.68 2.75 3.53 3.02 3.55 2.89

mean(0-25)= 3.68 2.75 3.53 3.02 3.55 2.89

mean(0-50)= 3.68 2.75 3.53 3.02 3.55 2.89

mean(0-200)= 3.68 2.75 3.53 3.02 3.55 2.89

mean(0-1500)= 3.68 2.75 3.53 3.02 3.55 2.89

stdev(0-15)= 1.76 1.76 0.84 1.13 0.99 1.27

stdev(0-25)= 1.76 1.76 0.84 1.13 0.99 1.27

stdev(0-50)= 1.76 1.76 0.84 1.13 0.99 1.27

stdev(0-200)= 1.76 1.76 0.84 1.13 0.99 1.27

stdev(0-1500)= 1.76 1.76 0.84 1.13 0.99 1.27


94

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

0 2 4 6 8

MU/cGy

NRSN 3 6X IMRT

RSN 3 6X

RSN 3 15X IMRT

RSN 3 15X

RSN 3 All IMRT

RSN 3 All Energies



95

RSN 3 6X IMRT

RSN 3 6X

RSN 3 15X IMRT

RSN 3 15X

RSN 3 All IMRT

RSN 3 All Energies

mean(0-15)= 6.18 3.90 3.54 3.10 3.61 3.10

mean(0-25)= 6.18 3.90 3.54 3.10 3.61 3.10

mean(0-50)= 6.18 3.90 3.54 3.10 3.61 3.10

mean(0-200)= 6.18 3.90 3.54 3.10 3.61 3.10

mean(0-1500)= 6.18 3.90 3.54 3.10 3.61 3.10

stdev(0-15)= 0.98 2.40 0.60 1.06 0.73 1.16

stdev(0-25)= 0.98 2.40 0.60 1.06 0.73 1.16

stdev(0-50)= 0.98 2.40 0.60 1.06 0.73 1.16

stdev(0-200)= 0.98 2.40 0.60 1.06 0.73 1.16

stdev(0-1500)= 0.98 2.40 0.60 1.06 0.73 1.16


96

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

0 2 4 6 8 10

MU/cGy

N

RSN 4 6X IMRT

RSN 4 6X

RSN 4 15X IMRT

RSN 4 15X

RSN 4 All IMRT

RSN 4 All Energies



97

RSN 4 6X IMRT

RSN 4 6X

RSN 4 15X IMRT

RSN 4 15X

RSN 4 All IMRT

RSN 4 All Energies

mean(0-15)= 3.48 2.64 3.81 3.10 3.74 2.90

mean(0-25)= 3.48 2.64 3.81 3.10 3.74 2.90

mean(0-50)= 3.48 2.64 3.81 3.10 3.74 2.90

mean(0-200)= 3.48 2.64 3.81 3.10 3.74 2.90

mean(0-1500)= 3.48 2.64 3.81 3.10 3.74 2.90

stdev(0-15)= 0.78 1.25 0.84 3.31 0.84 1.33

stdev(0-25)= 0.78 1.25 0.84 3.31 0.84 1.33

stdev(0-50)= 0.78 1.25 0.84 3.31 0.84 1.33

stdev(0-200)= 0.78 1.25 0.84 3.31 0.84 1.33

stdev(0-1500)= 0.78 1.25 0.84 3.31 0.84 1.33


98

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0 1 2 3 4 5 6 7 8 9 10

MU/cGy

N

RSN 5 6X IMRT

RSN 5 6X

RSN 5 15X IMRT

RSN 5 15X

RSN 5 All IMRT

RSN 5 All Energies



99

RSN 5 6X IMRT

RSN 5 6X

RSN 5 15X IMRT

RSN 5 15X

RSN 5 All IMRT

RSN 5 All Energies

mean(0-15)= 1.75 1.51 3.36 2.74 3.26 2.40

mean(0-25)= 1.75 1.51 3.36 3.26 3.26 2.80

mean(0-50)= 1.75 1.51 3.36 3.26 3.26 2.80

mean(0-200)= 1.75 1.51 3.36 3.26 3.26 2.80

mean(0-1500)= 1.75 1.51 3.36 3.26 3.26 2.80

stdev(0-15)= 0.00 0.40 1.07 1.29 1.10 1.27

stdev(0-25)= 0.00 0.40 1.07 1.29 1.10 1.27

stdev(0-50)= 0.00 0.40 1.07 1.29 1.10 1.27

stdev(0-200)= 0.00 0.40 1.07 1.29 1.10 1.27

stdev(0-1500)= 0.00 0.40 1.07 1.29 1.10 1.27


100

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

0 2 4 6 8 10

MU/cGy

N

RSN 6 6X IMRT

RSN 6 6X



101



mean(0-15)= 3.04 2.78

mean(0-25)= 3.04 2.78

mean(0-50)= 3.04 2.78

mean(0-200)= 3.04 2.78

mean(0-1500)= 3.04 2.78

stdev(0-15)= 1.53 1.54

stdev(0-25)= 1.53 1.54

stdev(0-50)= 1.53 1.54

stdev(0-200)= 1.53 1.54

stdev(0-1500)= 1.53 1.54

102

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

0 2 4 6 8 10

MU/cGy

N

RSN 1 6X IMRT

RSN 1 6X

RSN 1 15X IMRT

RSN 1 15X

RSN 1 All IMRT

RSN 1 All Energies



103

RSN 1 6X IMRT

RSN 1 6X

RSN 1 15X IMRT

RSN 1 15X

RSN 1 All IMRT

RSN 1 All Energies

mean(0-15)= 3.02 2.44 3.95 3.59 3.35 2.64

mean(0-25)= 3.02 2.44 3.95 3.59 3.35 2.64

mean(0-50)= 3.02 2.44 3.95 3.59 3.35 2.64

mean(0-200)= 3.02 2.44 3.95 3.59 3.35 2.64

mean(0-1500)= 3.02 2.44 3.95 3.59 3.35 2.64

stdev(0-15)= 1.47 1.40 0.74 1.11 1.34 1.41

stdev(0-25)= 1.47 1.40 0.74 1.11 1.34 1.41

stdev(0-50)= 1.47 1.40 0.74 1.11 1.34 1.41

stdev(0-200)= 1.47 1.40 0.74 1.11 1.34 1.41

stdev(0-1500)= 1.47 1.40 0.74 1.11 1.34 1.41


104

0.0

10.0

20.0

30.0

40.0

50.0

60.0

0 2 4 6 8 10

MU/cGy

N

RSN 2 6X IMRT

RSN 2 6X

RSN 2 15X IMRT

RSN 2 15X

RSN 2 All IMRT

RSN 2 All Energies



105

RSN 2 6X IMRT

RSN 2 6X

RSN 2 15X IMRT

RSN 2 15X

RSN 2 All IMRT

RSN 2 All Energies

mean(0-15)= 2.50 1.83 5.01 3.91 4.76 3.44

mean(0-25)= 2.50 1.83 5.01 3.91 4.76 3.44

mean(0-50)= 2.50 1.83 5.01 3.91 4.76 3.44

mean(0-200)= 2.50 1.83 5.01 3.91 4.76 3.44

mean(0-1500)= 2.50 1.83 5.01 3.91 4.76 3.44

stdev(0-15)= 0.25 0.52 1.96 2.28 2.00 2.22

stdev(0-25)= 0.25 0.52 1.96 2.28 2.00 2.22

stdev(0-50)= 0.25 0.52 1.96 2.28 2.00 2.22

stdev(0-200)= 0.25 0.52 1.96 2.28 2.00 2.22

stdev(0-1500)= 0.25 0.52 1.96 2.28 2.00 2.22


106

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

0 2 4 6 8 10

MU/cGy

N

RSN 1 16X IMRT

RSN 1 16X



107


mean(0-15)= 3.80 2.60

mean(0-25)= 3.80 2.60

mean(0-50)= 3.80 2.60

mean(0-200)= 3.80 2.60

mean(0-1500)= 3.80 2.60

stdev(0-15)= 0.82 1.33

stdev(0-25)= 0.82 1.33

stdev(0-50)= 0.82 1.33

stdev(0-200)= 0.82 1.33

stdev(0-1500)= 0.82 1.33


108

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

0 2 4 6 8 10 12 14

MU/cGy

N

RSN 2 6X IMRT

RSN 2 6X

RSN 2 16X IMRT

RSN 2 16X

RSN 2 All IMRT

RSN 2 All Energies



109

RSN 2 6X IMRT

RSN 2 6X

RSN 2 16X IMRT

RSN 2 16X

RSN 2 All IMRT

RSN 2 All Energies

mean(0-15)= 8.57 4.73 3.89 3.18 5.82 3.91

mean(0-25)= 8.57 4.73 3.89 3.18 5.82 3.91

mean(0-50)= 8.57 4.73 3.89 3.18 5.82 3.91

mean(0-200)= 8.57 4.73 3.89 3.18 5.82 3.91

mean(0-1500)= 8.57 4.73 3.89 3.18 5.82 3.91

stdev(0-15)= 1.87 3.68 1.62 1.77 2.88 18.92

stdev(0-25)= 1.87 3.68 1.62 1.77 2.88 18.92

stdev(0-50)= 1.87 3.68 1.62 1.77 2.88 18.92

stdev(0-200)= 1.87 3.68 1.62 1.77 2.88 18.92

stdev(0-1500)= 1.87 3.68 1.62 1.77 2.88 18.92


110

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

0 1 2 3 4 5 6 7 8

MU/cGy

N

RSN 1 18X IMRT

RSN 1 18X



111


mean(0-15)= 3.37 3.08

mean(0-25)= 3.37 3.08

mean(0-50)= 3.37 3.08

mean(0-200)= 3.37 3.08

mean(0-1500)= 3.37 3.08

stdev(0-15)= 0.68 0.95

stdev(0-25)= 0.68 0.95

stdev(0-50)= 0.68 0.95

stdev(0-200)= 0.68 0.95

stdev(0-1500)= 0.68 0.95


112

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0 1 2 3 4 5

MU/cGy

N

RSN 1 6X IMRT

RSN 1 6X

RSN 1 15X IMRT

RSN 1 15X

RSN 1 All IMRT

RSN 1 All Energies



113


RSN 1 6X IMRT

RSN 1 6X

RSN 1 15X IMRT

RSN 1 15X

RSN 1 All IMRT

RSN 1 All Energies

mean(0-15)= 1.96 1.64 3.53 2.93 2.83 1.99

mean(0-25)= 1.96 1.64 3.53 2.93 2.83 1.99

mean(0-50)= 1.96 1.64 3.53 2.93 2.83 1.99

mean(0-200)= 1.96 1.64 3.53 2.93 2.83 1.99

mean(0-1500)= 1.96 1.64 3.53 2.93 2.83 1.99

stdev(0-15)= 0.63 0.54 0.40 0.92 0.94 0.89

stdev(0-25)= 0.63 0.54 0.40 0.92 0.94 0.89

stdev(0-50)= 0.63 0.54 0.40 0.92 0.94 0.89

stdev(0-200)= 0.63 0.54 0.40 0.92 0.94 0.89

stdev(0-1500)= 0.63 0.54 0.40 0.92 0.94 0.89

114

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0 1 2 3 4 5 6 7 8

MU/cGy

N

RSN 2 6X IMRT

RSN 2 6X

RSN 2 15X IMRT

RSN 2 15X

RSN 2 All IMRT

RSN 2 All Energies



115

RSN 2 6X IMRT

RSN 2 6X

RSN 2 15X IMRT

RSN 2 15X

RSN 2 All IMRT

RSN 2 All Energies

mean(0-15)= 1.75 1.70 4.08 3.53 3.66 2.96

mean(0-25)= 1.75 1.70 4.08 3.53 3.66 2.96

mean(0-50)= 1.75 1.70 4.08 3.53 3.66 2.96

mean(0-200)= 1.75 1.70 4.08 3.53 3.66 2.96

mean(0-1500)= 1.75 1.70 4.08 3.53 3.66 2.96

stdev(0-15)= 0.00 0.72 1.35 1.57 1.51 1.61

stdev(0-25)= 0.00 0.72 1.35 1.57 1.51 1.61

stdev(0-50)= 0.00 0.72 1.35 1.57 1.51 1.61

stdev(0-200)= 0.00 0.72 1.35 1.57 1.51 1.61

stdev(0-1500)= 0.00 0.72 1.35 1.57 1.51 1.61


116

4X

HSN RSN IMRT MU/cGy C IMRT/C FI

Total Treatments

IMRT Treatments

15 3 8.03 1.72 4.66 0.38 2364 892

Table 2.46. 4 MV MU/cGy with unrestricted values.

6X IMRT Total IMRT

HSN RSN MU/cGy C IMRT/C FI Treatments Treatments

1 1 4.96 1.57 3.15 0.41 2062 842

1 2 5.04 1.65 3.05 0.28 1963 540

2 7 9.22 1.28 7.21 0.14 790 114

3 2 4.91 1.72 2.86 0.92 6174 5702

3 4 4.59 1.56 2.94 0.40 1705 679

3 5 7.37 1.55 4.74 0.71 1678 1193

3 6 4.51 1.94 2.32 0.31 577 178

5 2 3.11 1.47 2.11 0.03 1883 56

5 3 3.58 1.42 2.53 0.06 2381 141

6 2 6.33 1.24 5.11 0.95 1215 1154

7 1 6.78 1.62 4.19 0.53 2943 1567

8 1 8.34 1.25 6.67 0.90 6934 6271

8 2 10.17 1.20 8.47 0.91 4925 4459

9 1 3.88 1.75 2.22 0.41 2615 1067

10 3 11.52 2.15 5.35 0.64 1720 1104

11 1 1.68 1.90 0.88 0.08 2871 226

12 1 5.67 1.76 3.23 0.13 12608 1679

12 2 4.51 1.65 2.73 0.06 2672 169

13 1 19.11 1.75 10.93 0.86 10117 8738

14 1 3.96 1.21 3.28 0.36 2236 816

15 2 5.65 1.46 3.87 0.34 618 208

15 4 6.56 1.42 4.62 0.23 630 148

16 1 3.99 1.36 2.93 0.78 9035 7036

16 2 3.84 1.32 2.90 0.75 8780 6574

16 3 4.27 1.37 3.11 0.60 6797 4089

17 1 5.72 1.68 3.41 0.54 5669 3056

17 2 5.43 1.74 3.12 0.80 8260 6625

17 4 7.58 2.74 2.77 0.52 15330 7915

17 5 4.70 1.77 2.65 0.75 8871 6632

17 6 5.48 3.61 1.52 0.61 8005 4867

17 7 5.29 6.16 0.86 0.82 6731 5517

17 8 5.44 5.78 0.94 0.87 10120 8822

18 1 4.22 1.45 2.91 0.86 3603 3106

18 2 3.67 1.42 2.58 0.56 662 372

117

18 3 6.27 1.58 3.96 0.50 168 84

18 4 3.47 1.37 2.53 0.61 751 455

18 5 1.67 1.33 1.25 0.27 286 78

18 6 3.01 1.37 2.20 0.85 2416 2063

19 1 2.87 1.28 2.25 0.39 458 178

19 2 2.43 1.52 1.61 0.29 304 88

20 2 8.59 1.68 5.11 0.44 1160 514

22 1 1.85 1.52 1.22 0.22 653 143

22 2 1.65 1.71 0.96 0.42 448 186


15X

HSN RSN IMRT MU/cGy C IMRT/C FI Total Treatments IMRT Treatments

2 4 36.58 1.38 26.56 0.22 1759 392

2 7 2.91 1.45 2.01 0.03 1107 38

7 1 4.84 1.34 3.62 0.77 4746 3658

10 2 5.24 1 5.24 1.00 14943 14943

10 3 14.14 1.49 9.48 0.51 1030 526

15 2 4.43 1.30 3.41 0.73 2487 1814

15 4 6.69 1.34 4.98 0.54 1711 918

18 2 3.54 1.57 2.26 0.73 3769 2769

18 3 3.55 1.38 2.58 0.80 4317 3453

18 4 3.83 1.54 2.49 0.70 2604 1830

18 5 3.39 1.38 2.46 0.67 1693 1140

19 1 4.08 1.75 2.34 0.79 925 733

19 2 4.98 1.59 3.14 0.68 1201 816

22 1 3.46 1.88 1.85 0.64 274 176

22 2 4.12 1.71 2.41 0.77 1111 853


118

16X

HSN RSN IMRT MU/cGy C IMRT/C FI

Total Treatments

IMRT Treatments

20 1 3.84 1.43 2.68 0.49 973 475

20 2 3.91 1.47 2.66 0.71 1038 733


18X

HSN RSN IMRT

MU/cGy C IMRT/C FI Total

Treatments IMRT

Treatments

1 1 1.65 1.33 1.24 0.04 1185 50

5 2 3.88 1.18 3.30 0.74 5195 3836

11 1 2.21 1.17 1.90 0.41 2987 1232

12 2 4.23 1.21 3.50 0.54 23604 12859

13 1 7.40 2.67 2.77 0.47 9440 4439

21 1 3.39 1.49 2.28 0.85 3070 2605


20X

HSN RSN IMRT

MU/cGy C IMRT/C FI Total

Treatments IMRT

Treatments

5 3 3.57 1.42 2.52 0.73 5259 3850


119

4X

HSN RSN IMRT MU/cGy

15 3 8.01

Table 2.52. 4 MV MU/cGy with cutoffs

6X

HSN RSN IMRT MU/cGy HSN RSN IMRT MU/cGy

1 1 4.94 16 1 3.96

1 2 4.95 16 2 3.81

2 7 5.85 16 3 3.96

3 2 4.89 17 1 5.71

3 4 4.54 17 2 7.25

3 5 7.36 17 4 6.43

3 6 4.53 17 5 4.60

5 2 3.19 17 6 5.46

5 3 3.55 17 7 5.27

6 2 5.04 17 8 5.38

7 1 6.77 18 1 4.21

8 1 7.15 18 2 3.68

8 2 7.35 18 3 6.18

9 1 3.86 18 4 3.48

10 3 11.52 18 5 1.75

11 1 1.7 18 6 3.04

12 1 4.93 19 1 3.02

120

12 2 4.90 19 2 2.50

13 1 10.76 20 2 8.57

14 1 3.95 22 1 1.96

15 2 5.66 22 2 1.75

15 4 6.57

Table 2.53. 6 MV MU/cGy with cutoffs.

15X


2 4 3.14 18 3 3.54

2 7 3.00 18 4 3.81

7 1 4.82 18 5 3.36

10 2 5.23 19 1 3,95

10 3 14.14 19 2 5.01

15 2 4.40 22 1 3.53

15 4 6.67 22 2 4.08

18 2 3.53


121

16X


20 1 3.80 20 2 3.89


18X


1 1 1.58 12 2 4.21

5 2 3.87 13 1 6.49

11 1 2.22 21 1 3.37


20X

HSN RSN IMRT MU/cGy

5 3 3.59


TBI

HSN RSN TBI MU/cGy C TBI/C FI Total

Treatments TBI Treatments

9 1 35.65 1.39 25.57 0.02 1368 33

18X

14 1 19.89 1.21 16.48 0.04 2236 98

6X

16 2 23.71 1.31 18.16 0.01 2182 28

18X

18 5 20.89 1.38 15.13 0.01 1693 25

15X

Table 2.58. TBI MU/cGy with unrestricted values and different energies.

122

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164.

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Assessing Leakage Workloads of Medical Linear Accelerators