From the study, the upper bound of dose measured was 9.64 Gy which is lower than the tolerance dose. Results indicate that the percentage of both lens of eye for total treatment over the prescribe dose for the patients was ranged between 2.58% to

29.83% within the period of study which is the lowest percentage of dose was categorized in pediatrics and the highest percentage was in adults. The average doses obtained for the pediatric and adults patients were 2.57 Gy and 4.15 Gy

respectively. This result shows that average dose for pediatric patients was lower than adults which is contribute about 25% and 42% compared to tolerance dose. Meanwhile, the deviation of dose between left and right lens of eye obtained for the

pediatric and adult patients were 0.27 Gy and 0.49 Gy respectively.

RADIATION DOSE TO THE LENS OF THE PATIENT UNDERGOING CRANIAL AND CSI CASES

AT HOSPITAL KUALA LUMPURMusa M. A., Sidi Ahmad N. A., Mansor M. F., Ibrahim S., Abdullah M. K.

Department of Radiotherapy and Oncology , Hospital Kuala Lumpur, Malaysia

RESULTS

A retrospective study was performed for 46 patients consisting of pediatric patients (1.5-18 years) and adults (› 19 years) who received treatment in either Cranium Cases or Cranial Spinal Irradiation (CSI) between 2013 and 2014 at Radiotherapy & Oncology Department, Hospital Kuala Lumpur. The dose was measured using Thermoluminance Detector (TLD) chips.

METHOD

DISCUSSION

Figure 3: Dose Comparison Between Left and Right Lens for Pediatrics Patient

CONCLUSION

REFERENCES

INTRODUCTIONThe purpose of this study is to analyzed the dose to the lens of patients undergoing cranial and cranial spinal irradiation (CSI) in Hospital Kuala Lumpur. Normally the indications for this treatment is Medulloblastoma, Ependymoma, Germinoma and Pineal Gland. The target volume of the cranial cases is whole brain only while for CSI is included whole brain, spinal and posterior fossa. Since the treated area is around the whole brain and eye, and the dose tolerance of the lens is the lowest which is 10Gy, so we considered to measured the lens dose even though we already shield the lens during the planning process. So that we can minimized the risk of cataract when exceed the dose tolerance for lens.

Figure 4: Dose Comparison Between Left and Right Lens for Adults Patient

Table 1 : Total Dose Delivered From The Prescribed Dose For Lens

Figure 1: Total Dose Delivered for Different Group

Figure 2: Dose Comparison Between Adults and Pediatrics Patient

The average doses obtained for the pediatric and adults patients were 2.57 Gy and 4.15 Gy, respectively. This is because the separation of both eyes for adult patient much more bigger which contribute to higher doses. Besides, most of pediatrics patients are planned with shielded eyes to reduce the risk of cataract effect to the eyes.

The deviation of dose between left and right lens of eye obtained for the pediatric and adult patients were 0.27 Gy and 0.49 Gy, respectively.

Results indicate that the percentage of both lens of eye for total treatment over the prescribe dose for the patients was ranged between 2.58% to 29.83% within the period of study which is the lowest percentage of dose was categorized in pediatrics and the highest percentage was in adults.

This result shows that average dose for pediatric patients was lower than adults which is contribute about 25% and 42% compared to tolerance dose.

1. Practical radiotherapy planning, j. Dobbs Table 4.1 , pg 49