POSTER ON SPECT CT radiation dose from SIEMENS Symbia T16 presented at SKMCH&RC symposium on November, 2015, Lahore, Pakistan.

1. 7-A Block R III, Johar Town, Lahore, Pakistan
www.shaukatkhanum.org.pk
SHAUKAT KHANUM MEMORIAL
CANCER HOSPITAL & RESEARCH CENTRE
ReferencesConclusion
MATERIALS & METHODS
We analyzed 151 patients injected with 99mTc-MDP for bone scan, 20 patients for stress 99mTc-MIBI, 6 patients for 99mTc-
MIBI para-thyroid, 21 patients 99mTc HSA Sentinel, 45 patients Iodine whole-body post therapy. The CT and radiotracer
doses were calculated using ICRP conversion factors. The CT portion of SYMBIA T16 system has variable tube current
ranges from 20–345 mA.
Shahid Younas1, Syed Haris Ali1, Dr. Khalid Nawaz1, Humayun Bashir Dr1 , Sahar Shahid1, Asma Nisar1,
Dr. Maimoona Siddiqui1, Muhammad Bilal2, Ashfaq Zaman2, Madeeha Khalid3,
1- Nuclear Medicine department, Shaukat Khanum Memorial Cancer Hospital and Research Center, Lahore, Pakistan
2- Department of Physics, PIEAS, Islamabad.
3- Department of Physics, The Islamia University of Bahawalpur, Pakistan.
SPECT-CT: HOW MUCH RADIATION DOSE CT CONSTITUTE
CONCLUSION
The risk factor in our case is 0.016% with the addition of diagnostic CT for SPECT/CT. Considering the benefit to the patient in
comparison to conventional diagnostic CT the induced radiation doses by SPECT/CT are quite low in our calculations However,
effective dose of CT may be balanced further by decreasing the injected nuclear medicine activity at the cost of increased patient
scanning time.
RESULTS
The maximum dose for bone patients (%
increase with respect to radiotracer) is
1.99 mSv (45.76%) for 99mTc trunk
patients and least for head which bears
0.1 mSv (1.79%). The CT dose for
abdomen & Pelvis, Chest, Head & neck
is 0.78, 0.64, 0.18 mSv respectively.
However, chest dose in case 99mTc-MIBI
is 3.56 mSv in one phase of the
myocardial perfusion imaging. The
calculated neck CT dose for 99mTc
parathyroid is 0.8 mSv where as it
decreased to 0.75 mSv for the 99mTc
Sentinel chest patients. The negligible
dose rise is observed in case of Iodine-
131 post therapy patients with an
average CT dose of 1.02 mSv for trunk
areas against 1976 mSv dose from
radioactive Iodine.
OBJECTIVE:
Effective dose (E) is a single parameter to reflect the relative risk from exposure to ionizing radiation in term of
detrimental biologic effects on whole-body exposure. SPECT with multi-slice CT systems has been employed for better
attenuation correction and localization. The study was conducted to calculate effective radiation dose both from
radiotracer and the CT component of SPECT CT to patients scanned from August, 2014, to August, 2015, on SYMBIA T16
SPECT CT in the department of Nuclear Medicine.
REFERENCES
1. AAPM Task Group Report # 108
2. Pakistan Nuclear Regulatory Authority , PNRA, Regulation: Pak/904: Radiation Protection
3. Dose Record from Pakistan Institute of Nuclear Sciences and Technology (PINSTECH), Islamabad, Pakistan.
Sr. Primary Scan Radiation Induce Dose in SYMBIA T16 SPECT/CT
CT Dose
(mSv)
Radiopharmaceutical Dose
(mSv)
Accumulative
Dose
% increase
1
99m
Tc-MDP Bone
Chest 0.65
4.95
5.6 13.13
Abdomen & Pelvis 0.87 5.75 16.17
Trunk 10.45 15.4 211.11
Neck 0.29 5.24 5.85
2
99m
Tc-MIBI Myocardial Perfusion
Chest 3.67 6.96 10.62 52.72
3
99m
Tc-MIBI Parathyroid
Neck 0.8 7.58 8.37 10.55
4
99m
Tc-Sentinal
Chest 1.03 -
5
99m
Tc-Thyriod
Neck 0.01 2.15 2.16 0.46
6 131
NaI Post Therapy 0.43 2790 2790.43 0.015